000
FXUS65 KFGZ 200411
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
910 PM MST FRI SEP 19 2008

.SYNOPSIS...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
DIMINISH THIS EVENING. DRIER AND BREEZY CONDITIONS WILL DEVELOP OVER
THE WEEKEND. THESE DRY CONDITIONS WILL CONTINUE INTO NEXT WEEK ALONG
WITH SLIGHTLY WARMER TEMPERATURES.

&&

.DISCUSSION...GRIDDED FORECAST HAVE BEEN UPDATED TO TAKE INTO
ACCOUNT THE PERSISTENT SHOWER AND ISOLATED THUNDERSTORM ACTIVITY
THIS EVENING OVER THE LITTLE COLORADO RIVER VALLEY (LCR)...PRECIP
CHANCES WERE INCREASED FROM 10 TO 20 PERCENT AROUND THE PETRIFIED
FOREST NM.

A WESTWARD PROPAGATING OUTFLOW BOUNDARY APPEARS TO BE AIDING IN THE
WEAK LIFT OVER THE LCR...ALONG WITH STEEPER LAPSE RATES BETWEEN THE
700 TO 500 MB LAYER...ALONG WITH AN INCREASE IN LOW LEVEL MOISTURE
ASSOCIATED WITH THE OUTFLOW BOUNDARY. THE SHOWER ACTIVITY ASSOCIATED
WITH THIS FEATURE IS EXPECTED TO LAST THROUGH 1100 PM MST THIS
EVENING BEFORE DIMINISHING.

NO UPDATES ARE PLANNED TO THE FORECAST ZONES...THE CHANGES THAT WERE
MADE WILL NOT WARRANT A ZONE UPDATE.

&&

.PREVIOUS DISCUSSION /318 PM MST/...ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS DEVELOPED BY LATE MORNING ACROSS NORTHERN ARIZONA.
MOST STORMS HAVE BEEN WEAK TO MODERATE IN INTENSITY WITH VERY SMALL
HAIL AND GUSTY WINDS AT BEST. EXPECT MOST ACTIVITY TO DIMINISH
QUICKLY AFTER SUNSET.

FOR THE WEEKEND...IT APPEARS THAT SOME MOISTURE MAY LINGER ACROSS
NORTHERN ARIZONA ON SATURDAY...BUT MODELS ARE SHOWING CONDITIONS
BECOMING MORE STABLE THAN THE LAST TWO DAYS. OVERALL...IT LOOKS AS
IF THERE SHOULD BE LESS COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS
THE AREA TOMORROW. A WEST TO SOUTHWEST FLOW WILL BEGIN DRYING THINGS
OUT ON SUNDAY WITH LITTLE TO NO PRECIPITATION EXPECTED.
ADDITIONALLY...PRESSURE GRADIENTS WILL STRENGTHEN THIS WEEKEND AHEAD
OF A LOW PRESSURE SYSTEM PASSING BY TO THE NORTH. THIS SHOULD RESULT
IN BREEZY SOUTHWEST WINDS THROUGHOUT THE WEEKEND.

FOR THE COMING WEEK...A WEST TO SOUTHWEST FLOW WILL CONTINUE TO
SCOUR OUT MOISTURE DURING THE FIRST PART OF NEXT WEEK WITH BREEZY
CONDITIONS EXPECTED THROUGH AT LEAST MONDAY. MODELS ARE IN FAIRLY
GOOD AGREEMENT THAT HIGH PRESSURE WILL SET UP OVER THE SOUTHWEST
UNITED STATES BY MIDWEEK...BRINGING CONTINUED DRY CONDITIONS ALONG
WITH LIGHTER WINDS AND SLIGHTLY WARMER TEMPERATURES THROUGH THE REST
OF THE WEEK.

&&

.AVIATION...FOR THE 06Z PACKAGE...EXPECT ISOLATED SHOWER AND
THUNDERSTORMS TO CONTINUE ACROSS NRN AZ BEFORE DIMINISHING AFTER
06Z...WITH CONTINUED CLEARING CONDITIONS AFTERWARD. AFT 18Z
SAT...ISOLATED STORMS ARE FORECAST FOR THE HIGHER TERRAIN FROM THE
KAIBAB PLATEAU TO THE NORTHEAST PLATEAUS. AVIATION DISCUSSION NOT
UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.

MONDAY THROUGH WEDNESDAY...SOUTHWEST FLOW ALOFT WILL INCREASE ON
MONDAY AS A WEAK DISTURBANCE MOVES THROUGH THE GREAT BASIN. LOOK FOR
AFTERNOON WINDS AT OF 15-25 MPH. FOR TUESDAY AND WEDNESDAY...A
SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE MOUNTAINS WILL
CONTINUE....OTHERWISE EXPECT NEAR NORMAL TEMPERATURES AND DAYTIME
HUMIDITIES IN THE 15-30 PERCENT RANGE.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...............TC
AVIATION/FIRE WX.....TC

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

000
FXUS65 KTWC 200332
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
832 PM MST FRI SEP 19 2008

.SYNOPSIS...DRY WESTERLY FLOW WILL PROVIDE SOUTHEAST ARIZONA WITH
MOSTLY SUNNY DAYS AND CLEAR NIGHTS THROUGH THE WEEKEND INTO NEXT
WEEK. AFTERNOON HIGH TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HIGH PRESSURE ALOFT WILL BUILD OVER THE DESERT SOUTHWEST
NEXT WEEK...RESULTING IN A WARMING TREND WITH TEMPERATURES WELL
ABOVE NORMAL.

&&

.DISCUSSION...SATELLITE IMAGERY SHOWS A FEW CUMULUS CLOUDS ERODING
ACROSS PORTIONS OF THE STATE SINCE SUNSET. SHOULD HAVE MOSTLY CLEAR
SKIES OVERNIGHT ACROSS MOST OF MY FORECAST AREA. LIGHTNING DETECTION
AND RADAR MOSAIC STILL SHOW ISOLATED THUNDERSTORMS MAINLY OVER THE
HIGHER TERRAIN OF NORTHERN ARIZONA...AS WELL AS WEST CENTRAL NEW
MEXICO. I INHERITED A 20 PERCENT CHANCE OF SHOWERS OR THUNDERSTORMS
FOR THE WHITE MOUNTAINS OF NORTHERN GREENLEE COUNTY FOR THIS
EVENING. GIVEN THE CLOSE PROXIMITY OF THE SHOWERS AND STORMS TO THE
NORTH AND EAST WILL JUST LEAVE THE MENTION IN THE ZONES FOR THE
REMAINDER OF THE EVENING FOR ZONE 19. AFTER MIDNIGHT THE THREAT
SHOULD BE MINIMAL.

HIGH TEMPERATURES ACROSS MY FORECAST AREA THIS AFTERNOON RANGED FROM
81 DEGS AT BISBEE IN SOUTHERN COCHISE COUNTY...TO 99 DEGS AT PICACHO
PEAK STATE PARK IN SOUTHERN PINAL COUNTY. THE TUCSON INTL AIRPORT
RECORDED A HIGH OF 97 DEGS WHICH IS 4 DEGS ABOVE NORMAL FOR THIS
DATE. AS OF 03Z (8 PM MST)... TEMPS RANGED FROM THE LOWER 70S TO THE
MID 80S WITH TUCSON REPORTING A TEMP OF 86 DEGS. THE CURRENT TEMPS
SEEM TO BE ON TRACK WITH THE EXPECTED OVERNIGHT LOWS...SO NO CHANGES
ARE PLANNED AT THIS TIME. IN FACT...THE FORECAST FOR THE REMAINDER
OF TONIGHT LOOKS GOOD...SO NO UPDATES REQUIRED.

&&

.AVIATION...MOSTLY CLEAR SKIES OVERNIGHT AND EARLY SATURDAY WITH VFR
CONDITIONS EXPECTED. A FEW CUMULUS CLOUDS OVER THE HIGHER TERRAIN
SATURDAY AFTERNOON. LIGHT DIURNALLY DRIVEN WINDS AT 5-10 KTS THROUGH
SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.PREV DISCUSSION...LOW PRESSURE NEAR EUREKA CALIFORNIA THIS
AFTERNOON WILL DO LITTLE TO AFFECT US THIS FAR SOUTH IN SOUTHEAST
ARIZONA...AS IT SWINGS INTO THE NORTHERN ROCKIES. THEREFORE...EXPECT
MORE OF THE SAME THIS WEEKEND WITH HIGHS IN THE MID 90S FOR THE
VALLEYS AND DESERTS BOTH DAYS. 12Z ECMWF SHOWS HEIGHTS BEGINNING TO
BUILD ACROSS ARIZONA ABOUT TUESDAY...SO IF ANYTHING IT WILL GET
HOTTER NEXT WEEK. 12Z MEX GUIDANCE SHOWS THIS WITH HIGHS IN THE
UPPER 90S TO NEAR 100 FOR TUCSON...WELL ABOVE NORMAL FOR LATE
SEPTEMBER...AND OUR TEMPERATURE GRIDS HEAD THIS WAY WITH A WARMING
TREND BEGINNING WEDNESDAY.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

DISCUSSION...MOLLERE
PREVIOUS DISCUSSION...TURNER

WEATHER.GOV/TUCSON

000
FXUS65 KPSR 200319
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST FRI SEP 19 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...DRIER AIR WILL MOVE INTO THE REGION THROUGH THE WEEKEND
AS AN AREA OF LOW PRESSURE SETTLES ACROSS THE PACIFIC NORTHWEST. THE
DRY CONDITIONS WILL CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR RAIN
ACROSS THE REGION. HIGH TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY
ABOVE NORMAL WITH TEMPERATURES AT OR SLIGHTLY BELOW NORMAL.

&&

.DISCUSSION...
SKIES WERE MOSTLY CLEAR ACROSS THE FORECAST AREA (SOUTHEAST CA TO
SOUTH CENTRAL AZ) AT 03Z. THERE WERE VERY ISOLATED THUNDERSTORMS
OVER THE MOUNTAINS OF SOUTHWEST AZ FRIDAY AFTERNOON...AN INDICATION
THAT REMNANT MOISTURE CONTINUES IN THE AREA. MODELS FORECAST THIS
MOISTURE TO REMAIN OVER PORTIONS OF SOUTHWEST AND SOUTH CENTRAL AZ
THIS WEEKEND...HOWEVER THE ATMOSPHERE BECOMES A LITTLE MORE STABLE
FOR ANY AFTERNOON CONVECTION.  CURRENT FORECASTS LOOK OK. NO UPDATES
PLANNED. PREVIOUS DISCUSSION BELOW FROM THE DAY SHIFT STILL APPLIES.

PREVIOUS DISCUSSION...
FOR SATURDAY...AN UPPER LEVEL JET WILL APPROACH FROM THE NW WHICH
WILL CAUSE THE MID-LEVEL BAROTROPIC ZONE TO TIGHTEN. IN ADDITION A
VORT MAX WILL BE MOVING ALONG THIS MID-LEVEL FRONT. WHILE THIS
INITIALLY WOULD MAKE ONE THINK THERE WILL BE MORE THUNDERSTORM
ACTIVITY THE BOUNDARY LAYER WILL BE STRONGLY DRYING AND THE TIMING
OF THE VORT MAX APPEARS THAT IT/S MAIN FORCING WILL NOT COINCIDE
WITH MAX DAYTIME HEATING OVER OUR CWA. THEREFORE WILL CONTINUE WITH
LITTLE TO NO POPS SATURDAY. TEMPERATURES WILL SHOW LITTLE CHANGE
SATURDAY FROM FRIDAY.

MODELS REMAIN IN GOOD AGREEMENT ON THE FORECAST EVOLUTION THROUGH
THE WORK WEEK. A LARGE/SPRAWLING ANTI-CYCLONE WILL DEVELOP OVER THE
SOUTHWEST STATES BY MID-WEEK. LITTLE TO NO BOUNDARY LAYER MOISTURE
EXPECTED AS WELL SO LOOKING AT A DRY FORECAST THROUGH THE WEEK.
TEMPERATURES WILL SHOW SOME MINOR FLUCTUATIONS BUT OVERALL WILL
FEATURE MAX TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL WITH LOW
TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL.

PREVIOUS DISCUSSION...
MOST SIGNIFICANT ELEMENT IN TERMS OF IMPACT/SENSIBLE WX WILL BE THE
INCREASED THREAT FOR EARLY EVENING WIND GUSTS SUN-MON. GRADIENT WILL
TIGHTEN AHEAD OF THE TROUGH...PRODUCING WINDS 25-30 KT AT 700
MB...SO THE POTENTIAL IS THERE FOR THESE WINDS TO MIX DOWN IN THE
FORM OF GUSTS. THE PERSISTENT SOUTHWESTERLY FLOW WILL MAINTAIN THE
DRY CONDITIONS WITH NEGLIGIBLE POPS.

&&

.AVIATION...
SOUTHEAST CA...AND SOUTHWEST AND SOUTH CENTRAL AZ...INCLUDING KPHX...
KIWA...KNYL...KIPL...AND KBLH.    MOSTLY CLEAR SKIES AND LIGHT WIND
CAN BE EXPECTED THROUGH AT LEAST 03Z SUN.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MOSTLY CLEAR SKIES WITH DRY CONDITIONS ARE EXPECTED THROUGH THE
EXTENDED. WINDS WILL INCREASE SUNDAY EVENING AND AGAIN
MONDAY...AHEAD OF A LOW PRESSURE SYSTEM MOVING THROUGH THE PAC NW.
RH VALUES ARE EXPECTED TO DIP BELOW CRITICAL LEVELS ACROSS THE
SOUTHEAST CALIFORNIA DESERTS BY SUNDAY AFTERNOON...BUT SHOULD REMAIN
ABOVE CRITICAL LEVELS ELSEWHERE.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...VASQUEZ/INIGUEZ/HIRSCH
AVIATION...VASQUEZ
FIRE WEATHER...WANEK

000
FXUS65 KFGZ 192218
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
318 PM MST FRI SEP 19 2008

.SYNOPSIS...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
QUICKLY DIMINISH AFTER SUNSET THIS EVENING. DRIER AND BREEZY
CONDITIONS WILL DEVELOP OVER THE WEEKEND. THESE DRY CONDITIONS WILL
CONTINUE INTO NEXT WEEK ALONG WITH SLIGHTLY WARMER TEMPERATURES.

&&

.DISCUSSION...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPED BY LATE MORNING ACROSS NORTHERN ARIZONA. MOST STORMS HAVE
BEEN WEAK TO MODERATE IN INTENSITY WITH VERY SMALL HAIL AND GUSTY
WINDS AT BEST. EXPECT MOST ACTIVITY TO DIMINISH QUICKLY AFTER SUNSET.

FOR THE WEEKEND...IT APPEARS THAT SOME MOISTURE MAY LINGER ACROSS
NORTHERN ARIZONA ON SATURDAY...BUT MODELS ARE SHOWING CONDITIONS
BECOMING MORE STABLE THAN THE LAST TWO DAYS. OVERALL...IT LOOKS AS
IF THERE SHOULD BE LESS COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS
THE AREA TOMORROW. A WEST TO SOUTHWEST FLOW WILL BEGIN DRYING THINGS
OUT ON SUNDAY WITH LITTLE TO NO PRECIPITATION EXPECTED.
ADDITIONALLY...PRESSURE GRADIENTS WILL STRENGTHEN THIS WEEKEND AHEAD
OF A LOW PRESSURE SYSTEM PASSING BY TO THE NORTH. THIS SHOULD RESULT
IN BREEZY SOUTHWEST WINDS THROUGHOUT THE WEEKEND.

FOR THE COMING WEEK...A WEST TO SOUTHWEST FLOW WILL CONTINUE TO
SCOUR OUT MOISTURE DURING THE FIRST PART OF NEXT WEEK WITH BREEZY
CONDITIONS EXPECTED THROUGH AT LEAST MONDAY. MODELS ARE IN FAIRLY
GOOD AGREEMENT THAT HIGH PRESSURE WILL SET UP OVER THE SOUTHWEST
UNITED STATES BY MIDWEEK...BRINGING CONTINUED DRY CONDITIONS ALONG
WITH LIGHTER WINDS AND SLIGHTLY WARMER TEMPERATURES THROUGH THE REST
OF THE WEEK.

&&

.AVIATION...FOR THE 00Z PACKAGE...EXPECT SCATTERED THUNDERSTORMS TO
CONTINUE ACROSS NRN AZ THROUGH 02Z SAT...WITH CLEARING CONDITIONS
AFTERWARD. AFT 18Z SAT...ISOLATED STORMS ARE FORECAST FOR THE HIGHER
TERRAIN ALONG AND NORTH OF THE MOGOLLON RIM. AVIATION DISCUSSION NOT
UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.

MONDAY THROUGH WEDNESDAY...SOUTHWEST FLOW ALOFT WILL INCREASE ON
MONDAY AS A WEAK DISTURBANCE MOVES THROUGH THE GREAT BASIN. LOOK FOR
AFTERNOON WINDS AT OF 15-25 MPH. FOR TUESDAY AND WEDNESDAY...A
SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE MOUNTAINS WILL
CONTINUE....OTHERWISE EXPECT NEAR NORMAL TEMPERATURES AND DAYTIME
HUMIDITIES IN THE 15-30 PERCENT RANGE.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...............DDV
AVIATION/FIRE WX.....41

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

000
FXUS65 KPSR 192110
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
210 PM MST FRI SEP 19 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...DRIER AIR WILL MOVE INTO THE REGION THROUGH THE WEEKEND
AS AN AREA OF LOW PRESSURE SETTLES ACROSS THE PACIFIC NORTHWEST. THE
DRY CONDITIONS WILL CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR RAIN
ACROSS THE REGION. HIGH TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY
ABOVE NORMAL WITH TEMPERATURES AT OR SLIGHTLY BELOW NORMAL.

&&

.DISCUSSION...
NOT SURPRISINGLY WE/RE SEEING SOME MOUNTAIN-TOP THUNDERSTORMS
DEVELOPING ACROSS OUR CWA THIS AFTERNOON...MAINLY OVER THE MOUNTAINS
OF LA PAZ/YUMA/WRN MARICOPA COUNTIES. OBVIOUSLY NOT A LOT OF
INSTABILITY OR MOISTURE TO FEED THESE STORMS BASED ON THEIR OVERALL
WEAK STRUCTURE. IN ADDITION COVERAGE IS VERY LOW...FIVE PERCENT OR
LESS. SHWRS/STORMS WILL CONTINUE INTO THE EARLY EVENING BEFORE
DISSIPATING WITH LOSS OF SOLAR INSOLATION. WILL GO WITH COVERAGE
WORDING FOR AREAS WEST OF PHOENIX AND CHANCE WORDING FOR THE
MOUNTAINS OF SRN GILA COUNTY.

FOR SATURDAY...AN UPPER LEVEL JET WILL APPROACH FROM THE NW WHICH
WILL CAUSE THE MID-LEVEL BAROTROPIC ZONE TO TIGHTEN. IN ADDITION A
VORT MAX WILL BE MOVING ALONG THIS MID-LEVEL FRONT. WHILE THIS
INITIALLY WOULD MAKE ONE THINK THERE WILL BE MORE THUNDERSTORM
ACTIVITY THE BOUNDARY LAYER WILL BE STRONGLY DRYING AND THE TIMING
OF THE VORT MAX APPEARS THAT IT/S MAIN FORCING WILL NOT COINCIDE
WITH MAX DAYTIME HEATING OVER OUR CWA. THEREFORE WILL CONTINUE WITH
LITTLE TO NO POPS SATURDAY. TEMPERATURES WILL SHOW LITTLE CHANGE
SATURDAY FROM FRIDAY.

MODELS REMAIN IN GOOD AGREEMENT ON THE FORECAST EVOLUTION THROUGH
THE WORK WEEK. A LARGE/SPRAWLING ANTI-CYCLONE WILL DEVELOP OVER THE
SOUTHWEST STATES BY MID-WEEK. LITTLE TO NO BOUNDARY LAYER MOISTURE
EXPECTED AS WELL SO LOOKING AT A DRY FORECAST THROUGH THE WEEK.
TEMPERATURES WILL SHOW SOME MINOR FLUCTUATIONS BUT OVERALL WILL
FEATURE MAX TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL WITH LOW
TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL.

PREVIOUS DISCUSSION...
MOST SIGNIFICANT ELEMENT IN TERMS OF IMPACT/SENSIBLE WX WILL BE THE
INCREASED THREAT FOR EARLY EVENING WIND GUSTS SUN-MON. GRADIENT WILL
TIGHTEN AHEAD OF THE TROUGH...PRODUCING WINDS 25-30 KT AT 700
MB...SO THE POTENTIAL IS THERE FOR THESE WINDS TO MIX DOWN IN THE
FORM OF GUSTS. THE PERSISTENT SOUTHWESTERLY FLOW WILL MAINTAIN THE
DRY CONDITIONS WITH NEGLIGIBLE POPS.

&&

.AVIATION...
NO AVIATION CONCERNS EXPECTED THROUGH AT LEAST 18 UTC SATURDAY UNDER
MOSTLY CLEAR SKIES AND TYPICAL DIURNAL WIND FLUCTUATIONS.
CONVECTIVE ACTIVITY WILL BE LIMITED TODAY...WITH ONLY A SLIGHT
CHANCE OF A THUNDERSTORM OR TWO IN THE HIGHER TERRAIN EAST OF
PHOENIX. WINDS WILL INCREASE SUNDAY AFTERNOON AND AGAIN
MONDAY...AHEAD OF A LOW PRESSURE SYSTEM MOVING THROUGH THE PAC
NORTHWEST.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MOSTLY CLEAR SKIES WITH DRY CONDITIONS ARE EXPECTED THROUGH THE
EXTENDED. WINDS WILL INCREASE SUNDAY EVENING AND AGAIN
MONDAY...AHEAD OF A LOW PRESSURE SYSTEM MOVING THROUGH THE PAC NW.
RH VALUES ARE EXPECTED TO DIP BELOW CRITICAL LEVELS ACROSS THE
SOUTHEAST CALIFORNIA DESERTS BY SUNDAY AFTERNOON...BUT SHOULD REMAIN
ABOVE CRITICAL LEVELS ELSEWHERE.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...INIGUEZ/HIRSCH
AVIATION...ROGERS/WANEK
FIRE WEATHER...WANEK

000
FXUS65 KTWC 192040
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
140 PM MST FRI SEP 19 2008

.SYNOPSIS...DRY WESTERLY FLOW WILL PROVIDE SOUTHEAST ARIZONA WITH
MOSTLY SUNNY DAYS AND CLEAR NIGHTS THROUGH THE WEEKEND INTO NEXT
WEEK. AFTERNOON HIGH TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL. HIGH PRESSURE ALOFT WILL BUILD OVER THE DESERT SOUTHWEST
NEXT WEEK...RESULTING IN A WARMING TREND WITH TEMPERATURES WELL
ABOVE NORMAL.

&&

.DISCUSSION...RESIDUAL MOISTURE HAS BEEN ENOUGH TO GET A RATHER
EXPANSIVE CUMULUS FIELD GOING ACROSS SOUTHEAST ARIZONA THIS
AFTERNOON...WITH EVEN A FEW SMALL SHOWERS IN WESTERN PIMA AND PINAL
COUNTIES...AND OVER SONORA SOUTH OF NOGALES. LOW GRADE POPS ARE IN
THE FORECAST FOR ONE MORE EVENING FOR THE WHITE MOUNTAINS OF THE
NORTHERN CWA...BUT CERTAINLY NOT EXPECTING MUCH WITH VERY LITTLE
INSTABILITY AND STRONG CAPPING NEAR 550 MB ON THE 12Z KTWC SOUNDING.
CUMULUS ARE QUITE FLAT LOOKING OUT THE WINDOW HERE IN TUCSON...SO
ANY RAINFALL WILL BE VERY HARD TO COME BY THIS EVENING.

LOW PRESSURE NEAR EUREKA CALIFORNIA THIS AFTERNOON WILL DO LITTLE TO
AFFECT US THIS FAR SOUTH IN SOUTHEAST ARIZONA...AS IT SWINGS INTO
THE NORTHERN ROCKIES. THEREFORE...EXPECT MORE OF THE SAME THIS
WEEKEND WITH HIGHS IN THE MID 90S FOR THE VALLEYS AND DESERTS BOTH
DAYS. 12Z ECMWF SHOWS HEIGHTS BEGINNING TO BUILD ACROSS ARIZONA
ABOUT TUESDAY...SO IF ANYTHING IT WILL GET HOTTER NEXT WEEK. 12Z MEX
GUIDANCE SHOWS THIS WITH HIGHS IN THE UPPER 90S TO NEAR 100 FOR
TUCSON...WELL ABOVE NORMAL FOR LATE SEPTEMBER...AND OUR TEMPERATURE
GRIDS HEAD THIS WAY WITH A WARMING TREND BEGINNING WEDNESDAY.

&&

.AVIATION...CUMULUS CLOUDS AND VERY ISOLATED SHOWERS DISSIPATING AT
SUNSET THIS EVENING...WITH CLEAR SKIES AND VFR CONDITIONS EXPECTED
AT 12Z SATURDAY. MOSTLY CLEAR SKIES SATURDAY...WITH A FEW CUMULUS ON
THE HIGHER TERRAIN. LIGHT DIURNALLY DRIVEN WINDS AT 5-10 KTS THROUGH
SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

TURNER

WEATHER.GOV/TUCSON

000
FXUS65 KPSR 191729 AAA
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1030 AM MST FRI SEP 19 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.UPDATE...UPDATED AVIATION DISCUSSION.

&&

.SYNOPSIS...DRIER AIR WILL MOVE INTO THE REGION THROUGH THE WEEKEND
AS AN AREA OF LOW PRESSURE SETTLES ACROSS THE PACIFIC NORTHWEST. THE
DRY CONDITIONS WILL CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR
RAIN...EVEN ACROSS THE HIGHER TERRAIN EAST OF PHOENIX. TEMPERATURES
WILL REMAIN NEAR OR SLIGHTLY BELOW NORMAL.

&&

.DISCUSSION...
WATER VAPOR CLEARLY SHOWS A STRONG SHORTWAVE MOVING INTO NRN CA/SRN
OR THIS MORNING WITH TWO VORT MAXES ON THE SRN PERIPHERY...ONE
MOVING INTO AZ AND THE OTHER INTO CNTRL/SRN CA. THE MORE SIGNIFICANT
DYNAMICS ASSOCIATED WITH THIS SYSTEM WILL REMAIN WELL NORTH OF OUR
FORECAST AREA...THOUGH THE PVA ASSOCIATED WITH THE TWO VORT MAXES
WILL WARRANT THE MENTION OF LOW-END POPS OVER OUR MOUNTAINS. STILL
SOME MID-LEVEL MOISTURE OUT THERE AS EVIDENT BY THE CLOUDS THIS
MORNING. MODELS AGREE THAT THE BOUNDARY LAYER MOISTURE WILL BEGIN TO
DECREASE IN THE WAKE OF THE FIRST VORT LOBE. WITH A SHORTWAVE RIDGE
MOVING IN THIS EVENING EXPECT CONVECTIVE CLOUDS TO QUICKLY
DISSIPATE. SECOND VORT LOBE MOVING IN SATURDAY WILL GET A LITTLE
MORE DYNAMIC HELP AS A UL JET NOSES IN FROM THE NW BUT WILL BE
HINDERED BY A DECREASE IN MOISTURE AND THEREFORE THE VERY LOW POPS
FOR SATURDAY LOOK GOOD. TEMPERATURES CURRENTLY ON TRACK.

PREVIOUS DISCUSSION...
SAT-MON...MODELS IN GOOD AGREEMENT THAT A BROAD TROUGH WILL MOVE
EASTWARD OFF THE PACIFIC AND INTO THE NORTHERN ROCKIES. AHEAD OF
THIS SYSTEM...TEMPERATURES WILL PEAK SAT BEFORE A GRADUAL COOLING
TREND BEGINS SUN-MON. MOST SIGNIFICANT ELEMENT IN TERMS OF
IMPACT/SENSIBLE WX WILL BE THE INCREASED THREAT FOR EARLY EVENING
WIND GUSTS SUN-MON. GRADIENT WILL TIGHTEN AHEAD OF THE
TROUGH...PRODUCING WINDS 25-30 KT AT 700 MB...SO THE POTENTIAL IS
THERE FOR THESE WINDS TO MIX DOWN IN THE FORM OF GUSTS. THE
PERSISTENT SOUTHWESTERLY FLOW WILL MAINTAIN THE DRY CONDITIONS WITH
NEGLIGIBLE POPS.

EXTENDED...LONGWAVE PATTERN EXPECTED TO FEATURE A TROUGH ACROSS THE
NORTHERN LATITUDES AND A RIDGE ACROSS THE SUBTROPICS...YIELDING A
ZONAL FLOW ACROSS THE DESERT SOUTHWEST. TEMPS MAY INITIALLY FALL
BELOW AVERAGE BEHIND THE NORTHERN ROCKIES TROUGH TUE...BUT QUICKLY
RECOVER TO NEAR NORMAL VALUES TOWARDS THE END OF THE WEEK.

&&

.AVIATION...
NO AVIATION CONCERNS EXPECTED THROUGH AT LEAST 18 UTC SATURDAY UNDER
MOSTLY CLEAR SKIES AND TYPICAL DIURNAL WIND FLUCTUATIONS.
CONVECTIVE ACTIVITY WILL BE LIMITED TODAY...WITH ONLY A SLIGHT
CHANCE OF A THUNDERSTORM OR TWO IN THE HIGHER TERRAIN EAST OF
PHOENIX. WINDS WILL INCREASE SUNDAY AFTERNOON AND AGAIN
MONDAY...AHEAD OF A LOW PRESSURE SYSTEM MOVING THROUGH THE PAC
NORTHWEST.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MOSTLY CLEAR SKIES WITH DRY CONDITIONS ARE EXPECTED THROUGH THE
EXTENDED. WINDS WILL INCREASE SUNDAY EVENING AND AGAIN
MONDAY...AHEAD OF A LOW PRESSURE SYSTEM MOVING THROUGH THE PAC NW.
RH VALUES ARE EXPECTED TO DIP BELOW CRITICAL LEVELS ACROSS THE
SOUTHEAST CALIFORNIA DESERTS BY SUNDAY AFTERNOON...BUT SHOULD REMAIN
ABOVE CRITICAL LEVELS ELSEWHERE.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...INIGUEZ/HIRSCH
AVIATION...ROGERS/WANEK
FIRE WEATHER...WANEK

000
FXUS65 KPSR 191634
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
934 AM MST FRI SEP 19 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...DRIER AIR WILL MOVE INTO THE REGION THROUGH THE WEEKEND
AS AN AREA OF LOW PRESSURE SETTLES ACROSS THE PACIFIC NORTHWEST. THE
DRY CONDITIONS WILL CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR
RAIN...EVEN ACROSS THE HIGHER TERRAIN EAST OF PHOENIX. TEMPERATURES
WILL REMAIN NEAR OR SLIGHTLY BELOW NORMAL.

&&

.DISCUSSION...
WATER VAPOR CLEARLY SHOWS A STRONG SHORTWAVE MOVING INTO NRN CA/SRN
OR THIS MORNING WITH TWO VORT MAXES ON THE SRN PERIPHERY...ONE
MOVING INTO AZ AND THE OTHER INTO CNTRL/SRN CA. THE MORE SIGNIFICANT
DYNAMICS ASSOCIATED WITH THIS SYSTEM WILL REMAIN WELL NORTH OF OUR
FORECAST AREA...THOUGH THE PVA ASSOCIATED WITH THE TWO VORT MAXES
WILL WARRANT THE MENTION OF LOW-END POPS OVER OUR MOUNTAINS. STILL
SOME MID-LEVEL MOISTURE OUT THERE AS EVIDENT BY THE CLOUDS THIS
MORNING. MODELS AGREE THAT THE BOUNDARY LAYER MOISTURE WILL BEGIN TO
DECREASE IN THE WAKE OF THE FIRST VORT LOBE. WITH A SHORTWAVE RIDGE
MOVING IN THIS EVENING EXPECT CONVECTIVE CLOUDS TO QUICKLY
DISSIPATE. SECOND VORT LOBE MOVING IN SATURDAY WILL GET A LITTLE
MORE DYNAMIC HELP AS A UL JET NOSES IN FROM THE NW BUT WILL BE
HINDERED BY A DECREASE IN MOISTURE AND THEREFORE THE VERY LOW POPS
FOR SATURDAY LOOK GOOD. TEMPERATURES CURRENTLY ON TRACK.

PREVIOUS DISCUSSION...
SAT-MON...MODELS IN GOOD AGREEMENT THAT A BROAD TROUGH WILL MOVE
EASTWARD OFF THE PACIFIC AND INTO THE NORTHERN ROCKIES. AHEAD OF
THIS SYSTEM...TEMPERATURES WILL PEAK SAT BEFORE A GRADUAL COOLING
TREND BEGINS SUN-MON. MOST SIGNIFICANT ELEMENT IN TERMS OF
IMPACT/SENSIBLE WX WILL BE THE INCREASED THREAT FOR EARLY EVENING
WIND GUSTS SUN-MON. GRADIENT WILL TIGHTEN AHEAD OF THE
TROUGH...PRODUCING WINDS 25-30 KT AT 700 MB...SO THE POTENTIAL IS
THERE FOR THESE WINDS TO MIX DOWN IN THE FORM OF GUSTS. THE
PERSISTENT SOUTHWESTERLY FLOW WILL MAINTAIN THE DRY CONDITIONS WITH
NEGLIGIBLE POPS.

EXTENDED...LONGWAVE PATTERN EXPECTED TO FEATURE A TROUGH ACROSS THE
NORTHERN LATITUDES AND A RIDGE ACROSS THE SUBTROPICS...YIELDING A
ZONAL FLOW ACROSS THE DESERT SOUTHWEST. TEMPS MAY INITIALLY FALL
BELOW AVERAGE BEHIND THE NORTHERN ROCKIES TROUGH TUE...BUT QUICKLY
RECOVER TO NEAR NORMAL VALUES TOWARDS THE END OF THE WEEK.

&&

.AVIATION...
SOUTHEAST CA TO SOUTH CENTRAL AZ...INCLUDING KIPL...KNYL...KBLH
KPHX...AND KIWA AIRFIELDS...

NO AVIATION CONCERNS EXPECTED THROUGH AT LEAST 18 UTC SATURDAY UNDER
MOSTLY CLEAR SKIES AND TYPICAL DIURNAL WIND FLUCTUATIONS. WINDS WILL
INCREASE SUNDAY AFTERNOON AND AGAIN MONDAY...AHEAD OF A LOW PRESSURE
SYSTEM MOVING THROUGH THE PAC NORTHWEST.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MOSTLY CLEAR SKIES WITH DRY CONDITIONS ARE EXPECTED THROUGH THE
EXTENDED. WINDS WILL INCREASE SUNDAY EVENING AND AGAIN
MONDAY...AHEAD OF A LOW PRESSURE SYSTEM MOVING THROUGH THE PAC NW.
RH VALUES ARE EXPECTED TO DIP BELOW CRITICAL LEVELS ACROSS THE
SOUTHEAST CALIFORNIA DESERTS BY SUNDAY AFTERNOON...BUT SHOULD REMAIN
ABOVE CRITICAL LEVELS ELSEWHERE.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...INIGUEZ/HIRSCH
AVIATION...WANEK
FIRE WEATHER...WANEK

000
FXUS65 KTWC 191623
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
923 AM MST FRI SEP 19 2008

.SYNOPSIS...A COUPLE OF SYSTEMS PASSING THROUGH THE WESTERN UNITED
STATES THIS WEEKEND AND BY THE MIDDLE OF NEXT WEEK WILL BRUSH
NORTHERN ARIZONA. THESE SYSTEMS COULD BRING SOME SHOWERS AS FAR
SOUTH AS THE WHITE MOUNTAINS...BUT OVERALL THEY WILL HAVE VERY
LITTLE IMPACT ON THE WEATHER ACROSS SOUTHEAST ARIZONA. EXPECT NEAR
NORMAL DAYTIME HIGH TEMPERATURES THROUGH NEXT WEEK.

&&

.DISCUSSION...A FEW PATCHES OF CLOUDS THIS MORNING OTHERWISE A SUNNY
SKY PREVAILED ACROSS SOUTHEAST ARIZONA. STILL A BIT OF MOISTURE
AROUND FOR SOME AFTERNOON CU...POSSIBLY A STORM OR TWO IN THE WHITES
AND IN EASTERN COCHISE COUNTY. HIGH TEMPERATURES TODAY WILL BE
SIMILAR TO WHAT OCCURRED ON THURSDAY.

&&

.AVIATION...MOSTLY CLEAR SKIES ACROSS MUCH OF SE AZ TODAY INTO
TONIGHT. PARTLY CLOUDY WHITE MOUNTAINS WITH A SLIGHT CHANCE OF
TSRA/SHRA DURING THE 18Z-03Z PERIOD. LIGHT SURFACE WINDS INTO
SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

WEATHER.GOV/TUCSON

000
FXUS65 KFGZ 191601
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
901 AM MST FRI SEP 19 2008

.SYNOPSIS...ANOTHER DAY OF ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS IS EXPECTED TODAY. DRIER AND BREEZY CONDITIONS WILL
DEVELOP OVER THE WEEKEND...ALONG WITH SLIGHTLY WARMER TEMPERATURES.

&&

.DISCUSSION...SCATTERED LOW TO MIDLEVEL CLOUDS ARE CURRENTLY PRESENT
OVER THE NORTHERN HALF OF THE FORECAST AREA WITH AN ISOLATED SHOWER
OR TWO NORTH OF INTERSTATE 40. CONDITIONS LOOK RIGHT FOR ANOTHER
ROUND OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
TODAY...PRIMARILY ACROSS THE HIGHER TERRAIN. CURRENT POPS LOOK IN
LINE WITH THE EXPECTED COVERAGE AND NO FORECAST UPDATES ARE PLANNED
THIS MORNING.

&&

.PREV DISCUSSION (335 AM MST)...MODEL SOUNDINGS AND UPPER AIR
PROFILES INDICATE THE INSTABILITY TODAY WILL NOT BE MUCH DIFFERENT
THAN THURSDAY. THE BOUNDARY LAYER MOISTURE IS STILL FAIRLY
IMPRESSIVE FOR THIS TIME OF YEAR AND FLOW IS NOT STRONG ENOUGH TO
SCOUR IT OUT. IN ADDITION TO THIS...WATER VAPOR IMAGERY INDICATES
THAT A WEAK WAVE SOUTH OF LAS VEGAS WILL MOVE THROUGH CENTRAL
ARIZONA TODAY. ALL THIS MEANS ANOTHER DAY OF LOW-END SCATTERED
POPS...ESPECIALLY FROM FLAGSTAFF NORTH AND EAST. WE HAVE RAISED POPS
SLIGHTLY FROM THE PREVIOUS FORECAST.

OVER THE WEEKEND...MOISTURE SLOWLY GETS SCOURED OUT AS STRONGER
WESTERLY FLOW DEVELOPS. IN ADDITION...SOME CAPPING WILL FORM OVER
THE STATE...NOT TREMENDOUSLY STRONG...BUT ENOUGH TO KEEP POPS IN THE
SINGLE DIGITS. BY EARLY NEXT WEEK...A WEAK MOISTURE FEED MAY DEVELOP
OVER THE EASTERN SECTIONS OF STATE FOR A SOMEWHAT HIGHER CHANCE OF
SHOWERS...BUT NOTHING TO GET TO EXCITED ABOUT. BY DAYS FIVE THROUGH
SEVEN...A LARGE RIDGE WILL MIGRATE INLAND OFF THE PACIFIC...AND ANY
CHANCE FOR PRECIPITATION SHOULD BE SHUT DOWN.

&&

.AVIATION...FOR THE 18Z PACKAGE...EXPECT SCATTERED THUNDERSTORMS
OVER THE HIGHER TERRAIN THROUGH 02Z SAT. IN THE LOWER ELEVATIONS
AFTER 20Z FRIDAY LOOK FOR ISOLATED THUNDERSTORMS. A FEW OF THE
STORMS WILL PRODUCE MVFR VSBY AND CEILINGS...ALONG WITH GUSTY WINDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.

SUNDAY THROUGH TUESDAY...SOUTHWEST FLOW WILL INCREASE AS A SERIES OF
WEAK WEATHER DISTURBANCES BRUSH NORTHERN ARIZONA. AS A RESULT...
EXPECT NEAR NORMAL TEMPERATURES...DAYTIME HUMIDITIES IN THE 15-30
PERCENT RANGE...AND BREEZY AFTERNOON SOUTHWEST WINDS OF 15-25 MPH. A
SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE MOUNTAINS WILL
CONTINUE.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...............DDV
AVIATION/FIRE WX.....41

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

000
FXUS65 KPSR 191321
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
622 AM MST FRI SEP 19 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.UPDATE...UPDATED AVIATION AND FIRE WX DISCUSSIONS.

&&

.SYNOPSIS...DRIER AIR WILL MOVE INTO THE REGION THROUGH THE WEEKEND
AS AN AREA OF LOW PRESSURE SETTLES ACROSS THE PACIFIC NORTHWEST. THE
DRY CONDITIONS WILL CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR
RAIN...EVEN ACROSS THE HIGHER TERRAIN EAST OF PHOENIX. TEMPERATURES
WILL REMAIN NEAR OR SLIGHTLY BELOW NORMAL.

&&

.DISCUSSION...
TODAY...LOW-LEVEL ANTICYCLONE ACROSS SE AZ WILL SLIDE EASTWARD AS A
LOW PRESSURE SYSTEM MOVES INTO THE GREAT BASIN. RESULTING
SOUTHWESTERLY FLOW WILL NOT OFFER MUCH IN THE WAY OF MOISTURE
ADVECTION...SO RAIN CHANCES WILL BE QUITE SLIM TODAY...GENERALLY
AROUND 5 PERCENT AND HIGHEST ACROSS THE CLIMATOLOGICALLY FAVORED
HIGHER TERRAIN. MAVS WERE A DEGREE TOO WARM AT KPHX YESTERDAY AND
WILL AGAIN UNDERCUT THE PROJECTED HIGH OF 101 DEGREES.

SAT-MON...MODELS IN GOOD AGREEMENT THAT A BROAD TROUGH WILL MOVE
EASTWARD OFF THE PACIFIC AND INTO THE NORTHERN ROCKIES. AHEAD OF
THIS SYSTEM...TEMPERATURES WILL PEAK SAT BEFORE A GRADUAL COOLING
TREND BEGINS SUN-MON. MOST SIGNIFICANT ELEMENT IN TERMS OF
IMPACT/SENSIBLE WX WILL BE THE INCREASED THREAT FOR EARLY EVENING
WIND GUSTS SUN-MON. GRADIENT WILL TIGHTEN AHEAD OF THE
TROUGH...PRODUCING WINDS 25-30 KT AT 700 MB...SO THE POTENTIAL IS
THERE FOR THESE WINDS TO MIX DOWN IN THE FORM OF GUSTS. THE
PERSISTENT SOUTHWESTERLY FLOW WILL MAINTAIN THE DRY CONDITIONS WITH
NEGLIGIBLE POPS.

EXTENDED...LONGWAVE PATTERN EXPECTED TO FEATURE A TROUGH ACROSS THE
NORTHERN LATITUDES AND A RIDGE ACROSS THE SUBTROPICS...YIELDING A
ZONAL FLOW ACROSS THE DESERT SOUTHWEST. TEMPS MAY INITIALLY FALL
BELOW AVERAGE BEHIND THE NORTHERN ROCKIES TROUGH TUE...BUT QUICKLY
RECOVER TO NEAR NORMAL VALUES TOWARDS THE END OF THE WEEK.

&&

.AVIATION...
SOUTHEAST CA TO SOUTH CENTRAL AZ...INCLUDING KIPL...KNYL...KBLH
KPHX...AND KIWA AIRFIELDS...

NO AVIATION CONCERNS EXPECTED THROUGH AT LEAST 18 UTC SATURDAY UNDER
MOSTLY CLEAR SKIES AND TYPICAL DIURNAL WIND FLUCTUATIONS. WINDS WILL
INCREASE SUNDAY AFTERNOON AND AGAIN MONDAY...AHEAD OF A LOW PRESSURE
SYSTEM MOVING THROUGH THE PAC NORTHWEST.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MOSTLY CLEAR SKIES WITH DRY CONDITIONS ARE EXPECTED THROUGH THE
EXTENDED. WINDS WILL INCREASE SUNDAY EVENING AND AGAIN
MONDAY...AHEAD OF A LOW PRESSURE SYSTEM MOVING THROUGH THE PAC NW.
RH VALUES ARE EXPECTED TO DIP BELOW CRITICAL LEVELS ACROSS THE
SOUTHEAST CALIFORNIA DESERTS BY SUNDAY AFTERNOON...BUT SHOULD REMAIN
ABOVE CRITICAL LEVELS ELSEWHERE.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
AVIATION...WANEK
FIRE WEATHER...WANEK

000
FXUS65 KFGZ 191039
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
335 AM MST FRI SEP 19 2008

.SYNOPSIS...ANOTHER DAY OF SCATTERED SHOWERS AND THUNDERSTORMS IS
EXPECTED TODAY. DRIER AND BREEZY CONDITIONS WILL DEVELOP OVER THE
WEEKEND...ALONG WITH SLIGHTLY WARMER TEMPERATURES.

&&

.DISCUSSION...MODEL SOUNDINGS AND UPPER AIR PROFILES INDICATE THE
INSTABILITY TODAY WILL NOT BE MUCH DIFFERENT THAN THURSDAY. THE
BOUNDARY LAYER MOISTURE IS STILL FAIRLY IMPRESSIVE FOR THIS TIME OF
YEAR AND FLOW IS NOT STRONG ENOUGH TO SCOUR IT OUT. IN ADDITION TO
THIS...WATER VAPOR IMAGERY INDICATES THAT A WEAK WAVE SOUTH OF LAS
VEGAS WILL MOVE THROUGH CENTRAL ARIZONA TODAY. ALL THIS MEANS
ANOTHER DAY OF LOW-END SCATTERED POPS...ESPECIALLY FROM FLAGSTAFF
NORTH AND EAST. WE HAVE RAISED POPS SLIGHTLY FROM THE PREVIOUS
FORECAST.

OVER THE WEEKEND...MOISTURE SLOWLY GETS SCOURED OUT AS STRONGER
WESTERLY FLOW DEVELOPS. IN ADDITION...SOME CAPPING WILL FORM OVER
THE STATE...NOT TREMENDOUSLY STRONG...BUT ENOUGH TO KEEP POPS IN THE
SINGLE DIGITS. BY EARLY NEXT WEEK...A WEAK MOISTURE FEED MAY DEVELOP
OVER THE EASTERN SECTIONS OF STATE FOR A SOMEWHAT HIGHER CHANCE OF
SHOWERS...BUT NOTHING TO GET TO EXCITED ABOUT. BY DAYS FIVE THROUGH
SEVEN...A LARGE RIDGE WILL MIGRATE INLAND OFF THE PACIFIC...AND ANY
CHANCE FOR PRECIPITATION SHOULD BE SHUT DOWN.

&&

.AVIATION...FOR THE 12Z PACKAGE...ANOTHER ROUND OF SCATTERED
THUNDERSTORMS IS EXPECTED OVER THE HIGHER TERRAIN AFTER 17Z...WITH
ISOLATED ACTIVITY MOVING INTO THE LOWER ELEVATIONS AFTER 20Z. A FEW
OF THE STORMS WILL PRODUCE MVFR VSBY AND CEILINGS...ALONG WITH GUSTY
WINDS. THE STORMS SHOULD DISSIPATE BY AROUND 02Z SATURDAY. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.

SUNDAY THROUGH TUESDAY...SOUTHWEST FLOW WILL INCREASE AS A SERIES OF
WEAK WEATHER DISTURBANCES BRUSH NORTHERN ARIZONA. AS A RESULT...
EXPECT NEAR NORMAL TEMPERATURES...DAYTIME HUMIDITIES IN THE 15-30
PERCENT RANGE...AND BREEZY AFTERNOON SOUTHWEST WINDS OF 15-25 MPH. A
SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE MOUNTAINS WILL
CONTINUE.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...............PETERSON
AVIATION/FIRE WX.....JJ

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

000
FXUS65 KPSR 190911
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
210 AM MST FRI SEP 19 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...DRIER AIR WILL MOVE INTO THE REGION THROUGH THE WEEKEND
AS AN AREA OF LOW PRESSURE SETTLES ACROSS THE PACIFIC NORTHWEST. THE
DRY CONDITIONS WILL CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR
RAIN...EVEN ACROSS THE HIGHER TERRAIN EAST OF PHOENIX. TEMPERATURES
WILL REMAIN NEAR OR SLIGHTLY BELOW NORMAL.

&&

.DISCUSSION...
TODAY...LOW-LEVEL ANTICYCLONE ACROSS SE AZ WILL SLIDE EASTWARD AS A
LOW PRESSURE SYSTEM MOVES INTO THE GREAT BASIN. RESULTING
SOUTHWESTERLY FLOW WILL NOT OFFER MUCH IN THE WAY OF MOISTURE
ADVECTION...SO RAIN CHANCES WILL BE QUITE SLIM TODAY...GENERALLY
AROUND 5 PERCENT AND HIGHEST ACROSS THE CLIMATOLOGICALLY FAVORED
HIGHER TERRAIN. MAVS WERE A DEGREE TOO WARM AT KPHX YESTERDAY AND
WILL AGAIN UNDERCUT THE PROJECTED HIGH OF 101 DEGREES.

SAT-MON...MODELS IN GOOD AGREEMENT THAT A BROAD TROUGH WILL MOVE
EASTWARD OFF THE PACIFIC AND INTO THE NORTHERN ROCKIES. AHEAD OF
THIS SYSTEM...TEMPERATURES WILL PEAK SAT BEFORE A GRADUAL COOLING
TREND BEGINS SUN-MON. MOST SIGNIFICANT ELEMENT IN TERMS OF
IMPACT/SENSIBLE WX WILL BE THE INCREASED THREAT FOR EARLY EVENING
WIND GUSTS SUN-MON. GRADIENT WILL TIGHTEN AHEAD OF THE
TROUGH...PRODUCING WINDS 25-30 KT AT 700 MB...SO THE POTENTIAL IS
THERE FOR THESE WINDS TO MIX DOWN IN THE FORM OF GUSTS. THE
PERSISTENT SOUTHWESTERLY FLOW WILL MAINTAIN THE DRY CONDITIONS WITH
NEGLIGIBLE POPS.

EXTENDED...LONGWAVE PATTERN EXPECTED TO FEATURE A TROUGH ACROSS THE
NORTHERN LATITUDES AND A RIDGE ACROSS THE SUBTROPICS...YIELDING A
ZONAL FLOW ACROSS THE DESERT SOUTHWEST. TEMPS MAY INITIALLY FALL
BELOW AVERAGE BEHIND THE NORTHERN ROCKIES TROUGH TUE...BUT QUICKLY
RECOVER TO NEAR NORMAL VALUES TOWARDS THE END OF THE WEEK.

&&

.AVIATION...
SOUTHEAST CA TO SOUTH CENTRAL AZ...INCLUDING KIPL...KNYL...KBLH
KPHX...AND KIWA AIRFIELDS...
  MOSTLY CLEAR SKIES AND LIGHT WINDS ARE EXPECTED THROUGH AT LEAST
03Z SAT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THE THREAT FOR ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE END
OF THE WEEK ACROSS THE LOWER COLORADO RIVER VALLEY AND SE CA. DRIER
AIR WILL MOVE WEST TO EAST ACROSS THE DESERT SOUTHWEST THIS WEEKEND
AS AN AREA OF LOW PRESSURE MOVES THROUGH THE GREAT BASIN. ALTHOUGH
WINDS ARE EXPECTED TO REMAIN BELOW CRITICAL THRESHOLDS...BREEZY
CONDITIONS MAY DEVELOP THIS WEEKEND...POSSIBLY BECOMING WINDY EARLY
NEXT WEEK AS A STRONG PACIFIC LOW PRESSURE SYSTEM SLIDES THROUGH THE
NORTHERN ROCKIES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
AVIATION...VASQUEZ
FIRE WEATHER...WANEK/HIRSCH

000
FXUS65 KTWC 190803
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
110 AM MST FRI SEP 19 2008

.SYNOPSIS...A COUPLE OF SYSTEMS PASSING THROUGH THE WESTERN UNITED
STATES THIS WEEKEND AND BY THE MIDDLE OF NEXT WEEK WILL BRUSH
NORTHERN ARIZONA. THESE SYSTEMS COULD BRING SOME SHOWERS AS FAR
SOUTH AS THE WHITE MOUNTAINS...BUT OVERALL THEY WILL HAVE VERY
LITTLE IMPACT ON THE WEATHER ACROSS SOUTHEAST ARIZONA. EXPECT NEAR
NORMAL DAYTIME HIGH TEMPERATURES THROUGH NEXT WEEK.

&&

.DISCUSSION...SKIES HAVE CLEARED OUT OVER SOUTHEAST ARIZONA AS
DEWPOINTS HOVER IN THE UPPER 40S TO LOWER 50S. KTWC SOUNDINGS OVER
THE LAST 36 HOURS INDICATE A DRYING TREND AS PW VALUES HAVE GONE
FROM AROUND AN INCH TO AROUND 0.63 OF AN INCH.

MODELS REFLECT THIS KEEPING SIGNIFICANT MOISTURE OUT OF MUCH OF THE
FORECAST AREA FOR THE FORECAST CYCLE. THE EXCEPTION BEING FAR
NORTHERN REACHES OF THE CWA...THE WHITE MTNS AND SUCH. SYSTEMS
PASSING THROUGH TO THE NORTH WILL BRING SOME MOISTURE DOWN INTO
NORTHERN AZ...TRICKLING DOWN INTO NORTHERN GREENLEE COUNTY...GIVING
RISE TO A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE IN THE
WEEKEND AND EARLY NEXT WEEK. ELSEWHERE...EXPECTING CONDITIONS IN THE
MOSTLY TO PARTLY SUNNY RANGE. AFTERNOON HIGH TEMPERATURES ARE
EXPECTED TO REMAIN NEAR SEASONAL NORMALS...WITH MOST HIGH
TEMPERATURES IN THE CWA RANGING FROM THE LOWER TO MID 90S...CLOSER
TO 100 IN THE WESTERN DESERTS.

INHERITED FORECAST DISPLAYS THE ABOVE PRETTY WELL. MADE A FEW MINOR
TWEAKS AND UPDATES...BUT OTHERWISE...NO MAJOR CHANGES.

&&

.AVIATION...MOSTLY CLEAR SKIES ACROSS MUCH OF SE AZ TODAY INTO
TONIGHT. PARTLY CLOUDY WHITE MOUNTAINS WITH A SLIGHT CHANCE OF
TSRA/SHRA DURING THE 18Z-03Z PERIOD. LIGHT SURFACE WINDS INTO
SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

SMR/BF

WEATHER.GOV/TUCSON

000
FXUS65 KFGZ 190416
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
915 PM MST FRI SEP 18 2008

.SYNOPSIS...EXPECT DECREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH THE WEEKEND AS DRIER AND MORE STABLE WESTERLY FLOW ALOFT
DEVELOPS. THIS WILL ALSO BRING LOCALLY BREEZY SOUTHWEST WINDS AND
SEASONABLE TEMPERATURES.

&&

.DISCUSSION...CURRENT AREA 88D RADARS SHOWING THAT THE SHOWER AND
THUNDERSTORM ACTIVITY HAS VIRTUALLY DIMINISHED TO ALMOST NOTHING
THIS EVENING. CURRENT FORECASTS FOR THE OVERNIGHT PERIOD LOOK
GOOD...NO UPDATES ARE PLANNED.

RIDGE OF HIGH PRESSURE ALOFT WILL PASS OVER THE REGION TONIGHT AND
FRIDAY. THE ATMOSPHERE WILL BE SOMEWHAT STABLE...HOWEVER NOT STABLE
ENOUGH TO RULE OUT ISOLATED WEAK SHOWERS AND THUNDERSTORM ACTIVITY
ACROSS THE AREA BY FRIDAY AFTERNOON...ESPECIALLY OVER THE HIGHER
TERRAIN. A TROUGH OF LOW PRESSURE IS FORECAST TO BRUSH NORTHERN
SECTIONS OF THE STATE ON SATURDAY...WITH THE BEST MOISTURE AND LIFT
NORTH OF INTERSTATE 40...FOR WIDELY SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY.

&&
PREVIOUS DISCUSSION /245 PM MST/...A PACIFIC TROUGH CONTINUES TO
MOVE SLOWLY TOWARD THE WEST COAST THIS AFTERNOON WITH DRY STABLE
WESTERLY FLOW ALOFT FILTERING ACROSS NORTHERN AZ AHEAD OF THE
TROUGH. THE MORNING SOUNDING AT FLAGSTAFF TODAY REFLECTED A VERY
SLIGHT INCREASE IN OVERALL MOISTURE COMPARED WITH
YESTERDAY...HOWEVER A SUBSTANTIAL WARMING AND DRYING AT AND ABOVE
500 MB. AS A RESULT...THUNDERSTORMS HAVE GENERALLY BEEN RELATIVELY
WEAK SO FAR TODAY...BUT COVERAGE SLIGHTLY HIGHER THAN EXPECTED OVER
THE WESTERN MOGOLLON RIM.

OVER THE NEXT FEW DAYS...THE TROUGH IS EXPECTED TO MOVE INLAND
ACROSS THE GREAT BASIN. THIS WILL CONTINUE TO BRING DRY AND STABLE
FLOW ALOFT ACROSS AZ...REDUCING POPS EVEN FURTHER OVER MOST OF THE
AREA WHILE BRINGING INCREASINGLY BREEZY SOUTHWEST WINDS. LATEST
FORECAST MODEL GUIDANCE...HOWEVER...INDICATES SOME
MOISTURE...INSTABILITY..AND DYNAMIC LIFT OVER THE FAR NORTHERN ZONES
SATURDAY...SO HAVE TRENDED POPS UPWARD THERE.

EARLY NEXT WEEK...ANOTHER TROUGH IS EXPECTED TO DROP SOUTHEASTWARD
ACROSS THE GREAT BASIN AND INTO NORTHERN AZ. STILL SOME UNCERTAINTY
THIS FAR OUT WITH THE TRAJECTORY AND ORIENTATION OF THIS
TROUGH...AND COULD BRING EITHER AN INCREASE OR DECREASE IN MOISTURE
DEPENDING ON HOW IT ENDS UP FORMING.

&&

.AVIATION...FOR THE 06Z PACKAGE...VFR CONDITIONS WILL PREVAIL
OVERNIGHT WITH CLEAR TO PARTLY CLOUDY CONDITIONS...CLOUD BASES
BETWEEN 9 TO 12 KFT AGL. ANOTHER ROUND OF ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED FRIDAY AFTERNOON WITH ACTIVITY
DIMINISHING BY AROUND 03Z. AVIATION DISCUSSION NOT UPDATED FOR
AMENDMENTS.

&&

.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.

SUNDAY THROUGH TUESDAY...SOUTHWEST FLOW WILL INCREASE AS A SERIES OF
WEAK WEATHER DISTURBANCES BRUSH NORTHERN ARIZONA. AS A
RESULT...EXPECT NEAR NORMAL TEMPERATURES...DAYTIME HUMIDITIES IN THE
20-30 PERCENT RANGE...AND AFTERNOON SOUTHWEST WINDS OF 15-25 MPH. A
SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE MOUNTAINS WILL
CONTINUE.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...............TC
AVIATION/FIRE WX.....TC

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

000
FXUS65 KTWC 190356
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
857 PM MST THU SEP 18 2008

.SYNOPSIS...A COUPLE OF SYSTEMS PASSING THROUGH THE WESTERN UNITED
STATES THIS WEEKEND AND BY THE MIDDLE OF NEXT WEEK WILL BRUSH
NORTHERN ARIZONA. THESE SYSTEMS COULD BRING SOME SHOWERS AS FAR
SOUTH AS THE WHITE MOUNTAINS...BUT OVERALL THEY WILL HAVE VERY
LITTLE IMPACT ON THE WEATHER ACROSS SOUTHEAST ARIZONA. EXPECT NEAR
NORMAL DAYTIME HIGH TEMPERATURES THROUGH NEXT WEEK.

&&

.DISCUSSION...ISOLATED SHOWERS AND THUNDERSTORMS OCCURRED TODAY
MAINLY OVER THE HIGHER TERRAIN OF NORTHERN ARIZONA...INCLUDING THE
MOGOLLON RIM AND THE WHITE MOUNTAINS OF EAST CENTRAL ARIZONA. IN
ADDITION...ISOLATED STORMS ALSO OCCURRED NEAR THE YUMA AREA.
OTHERWISE...MY FORECAST AREA WAS RATHER QUIET. WILL UPDATE THE GRIDS
AND ZONES TO REMOVE ANY MENTION OF RAIN CHANCES FOR THE REMAINDER OF
THE NIGHT.

THIS EVENINGS KTWC SOUNDING REVEALED A DRY AIRMASS WITH A PWAT OF
ONLY 0.63 INCHES...WHICH IS A SIGNIFICANT DIFFERENCE COMPARED TO 12
AND 24 HOURS AGO WHEN THE PWAT WAS 0.94 INCHES THIS MORNING AND 1.02
INCHES WEDNESDAY EVENING.

AS OF 03Z (8 PM MST)...TEMPERATURES RANGED FROM THE LOWER 70S TO THE
MID 80S ACROSS SOUTHEAST ARIZONA...WITH TUCSON REPORTING A TEMP OF
85 DEGS. THE TUCSON INTL AIRPORT REPORTED AN AFTERNOON HIGH OF 95
DEGS. CURRENT TEMPS SEEM TO BE ON TRACK WITH EXPECTED OVERNIGHT
LOWS...SO NO CHANGES PLANNED AT THIS TIME.

&&

.AVIATION...MOSTLY CLEAR SKIES OVERNIGHT WITH WINDS EXPECTED TO BE
DIURNAL IN NATURE. A FEW CUMULUS CLOUDS DEVELOPING AGAIN DURING THE
AFTERNOON ON FRIDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.PREV DISCUSSION...UPPER RIDGE AMPLIFYING OVER THE STATE FRIDAY WITH
DAYTIME TEMPERATURES SIMILAR TO TODAY. STILL ENOUGH MOISTURE AROUND
FOR A SLIGHT CHANCE OF STORMS EAST AND SOUTH OF TUCSON. THE STORM
SYSTEM CURRENTLY OFF THE OREGON/NORTHERN CALIFORNIA COAST WILL MOVE
THROUGH THE GREAT BASIN/NORTHERN ROCKIES ON SATURDAY. MODELS ARE NOW
A BIT FURTHER NORTH THAN PREVIOUS RUNS WITH THE ONLY IMPACT TO
SOUTHEAST ARIZONA BEING A SLIGHT CHANCE OF STORMS IN THE WHITE
MOUNTAINS.

GENERAL TROFINESS OVER THE AREA SUNDAY INTO EARLY NEXT WEEK THEN
STRONG RIDGE BUILDS OVER THE AREA DURING LATER HALF ON NEXT WEEK.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

MOLLERE

WEATHER.GOV/TUCSON

000
FXUS65 KPSR 190333
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
835 PM MST THU SEP 18 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...
DRYER CONDITIONS WILL PREVAIL AS HIGH PRESSURE BUILDS OVER THE
SOUTHWEST THROUGH THE WEEKEND. TEMPERATURES WILL REMAIN NEAR NORMAL.

&&

.DISCUSSION...
MOSTLY SKIES WERE NOTED OVER THE FORECAST AREA (SOUTHEAST CA TO
SOUTH CENTRAL AZ) AT 03Z. NO WEATHER PROBLEMS EXPECTED THROUGH
FRIDAY MORNING.

OTHERWISE...DEEP MONSOON MOISTURE WHICH COVERED A LARGE PART OF
SOUTHERN CA AND SOUTHWEST AZ WEDNESDAY AFTERNOON...HAD THINNED OVER
THE PAST 24 HOURS. VERY ISOLATED THUNDERSTORMS MANAGED TO DEVELOP
OVER THE HIGHEST TERRAIN THURSDAY AFTERNOON...LIKE 40 MILES
SOUTHWEST OF WICKENBURG...IN SOUTHEAST CA 25 MILES SOUTHWEST OF
BLYTHE OVER THE CHOCOLATE MOUNTAIN AERIAL GUNNERY RANGE...AND IN
JOSHUA TREE NATIONAL PARK.

MOISTURE WILL CONTINUE TO THIN FRIDAY...AND DESPITE A NUMBER OF
PACIFIC SHORTWAVES MOVING INTO THE WESTERN STATES NORTH OF AZ...THE
AIRMASS SEEMS STABLE ENOUGH TO PRECLUDE CONVECTION.

CURRENT FORECASTS OK. NO UPDATE PLANNED. PREVIOUS DISCUSSION
REGARDING EXTENDED PERIOD STILL APPLIES.

PREVIOUS DISCUSSION...
LOW PRESSURE SYSTEM CONTINUES TO MOVE TOWARDS CALIFORNIA AND WILL BE
OVER NORTHERN CALIFORNIA BY SATURDAY MORNING. ALONG WITH IT HIGH
PRESSURE WILL BUILD OVER SOUTHERN CALIFORNIA AND ARIZONA THUS
KEEPING THE REGION DRY. BY TUESDAY A LONGWAVE TROUGH WILL DEVELOP
AND SWEEP OVER THE DESERT SOUTHWEST.

&&

.AVIATION...
SOUTHEAST CA TO SOUTH CENTRAL AZ...INCLUDING KIPL...KNYL...KBLH
KPHX...AND KIWA AIRFIELDS...
  MOSTLY CLEAR SKIES AND LIGHT WINDS ARE EXPECTED THROUGH AT LEAST
03Z SAT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THE THREAT FOR ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE END
OF THE WEEK ACROSS THE LOWER COLORADO RIVER VALLEY AND SE CA. DRIER
AIR WILL MOVE WEST TO EAST ACROSS THE DESERT SOUTHWEST THIS WEEKEND
AS AN AREA OF LOW PRESSURE MOVES THROUGH THE GREAT BASIN. ALTHOUGH
WINDS ARE EXPECTED TO REMAIN BELOW CRITICAL THRESHOLDS...BREEZY
CONDITIONS MAY DEVELOP THIS WEEKEND...POSSIBLY BECOMING WINDY EARLY
NEXT WEEK AS A STRONG PACIFIC LOW PRESSURE SYSTEM SLIDES THROUGH THE
NORTHERN ROCKIES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...VASQUEZ/WATERS
AVIATION...VASQUEZ
FIRE WEATHER...WANEK/HIRSCH

000
FXUS65 KFGZ 182147
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
245 PM MST FRI SEP 18 2008

.SYNOPSIS...EXPECT DECREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH THE WEEKEND AS DRIER AND MORE STABLE WESTERLY FLOW ALOFT
DEVELOPS. THIS WILL ALSO BRING LOCALLY BREEZY SOUTHWEST WINDS AND
SEASONABLE TEMPERATURES.

&&

.DISCUSSION...A PACIFIC TROUGH CONTINUES TO MOVE SLOWLY TOWARD THE
WEST COAST THIS AFTERNOON WITH DRY STABLE WESTERLY FLOW ALOFT
FILTERING ACROSS NORTHERN AZ AHEAD OF THE TROUGH. THE MORNING
SOUNDING AT FLAGSTAFF TODAY REFLECTED A VERY SLIGHT INCREASE IN
OVERALL MOISTURE COMPARED WITH YESTERDAY...HOWEVER A SUBSTANTIAL
WARMING AND DRYING AT AND ABOVE 500 MB. AS A RESULT...THUNDERSTORMS
HAVE GENERALLY BEEN RELATIVELY WEAK SO FAR TODAY...BUT COVERAGE
SLIGHTLY HIGHER THAN EXPECTED OVER THE WESTERN MOGOLLON RIM.

OVER THE NEXT FEW DAYS...THE TROUGH IS EXPECTED TO MOVE INLAND
ACROSS THE GREAT BASIN. THIS WILL CONTINUE TO BRING DRY AND STABLE
FLOW ALOFT ACROSS AZ...REDUCING POPS EVEN FURTHER OVER MOST OF THE
AREA WHILE BRINGING INCREASINGLY BREEZY SOUTHWEST WINDS. LATEST
FORECAST MODEL GUIDANCE...HOWEVER...INDICATES SOME
MOISTURE...INSTABILITY..AND DYNAMIC LIFT OVER THE FAR NORTHERN ZONES
SATURDAY...SO HAVE TRENDED POPS UPWARD THERE.

EARLY NEXT WEEK...ANOTHER TROUGH IS EXPECTED TO DROP SOUTHEASTWARD
ACROSS THE GREAT BASIN AND INTO NORTHERN AZ. STILL SOME UNCERTAINTY
THIS FAR OUT WITH THE TRAJECTORY AND ORIENTATION OF THIS
TROUGH...AND COULD BRING EITHER AN INCREASE OR DECREASE IN MOISTURE
DEPENDING ON HOW IT ENDS UP FORMING.

&&

.AVIATION...FOR THE 00Z PACKAGE...ISOLATED THUNDERSTORMS WILL
CONTINUE INTO THE EARLY EVENING HOURS. OTHERWISE VFR CONDITIONS WILL
PREVAIL. EXPECT STORMS TO END WITH CLEARING SKIES AFTER 03Z. ANOTHER
ROUND OF ISOLATED THUNDERSTORMS IS EXPECTED FRIDAY AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.

SUNDAY THROUGH TUESDAY...SOUTHWEST FLOW WILL INCREASE AS A SERIES OF
WEAK WEATHER DISTURBANCES BRUSH NORTHERN ARIZONA. AS A
RESULT...EXPECT NEAR NORMAL TEMPERATURES...DAYTIME HUMIDITIES IN THE
20-30 PERCENT RANGE...AND AFTERNOON SOUTHWEST WINDS OF 15-25 MPH. A
SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE MOUNTAINS WILL
CONTINUE.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...............ONTON
AVIATION/FIRE WX.....MCCOLLUM

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

000
FXUS65 KPSR 182127
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
230 PM MST THU SEP 18 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...
DRYER CONDITIONS WILL PREVAIL AS HIGH PRESSURE BUILDS OVER THE
SOUTHWEST THROUGH THE WEEKEND. TEMPERATURES WILL REMAIN NEAR NORMAL.

&&

.DISCUSSION...
SATELLITE AND RADAR INDICATE ISOLATED SHOWER ACTIVITY MOSTLY ALONG
THE I-10 CORRIDOR IN RIVERSIDE COUNTY IN CALIFORNIA AND LA PAZ
COUNTY IN ARIZONA. SHOWERS ARE LESS NUMEROUS AND INTENSE THAN THOSE
YESTERDAY. SURFACE OBS SHOWING DEW POINTS STARTING TO DROP ACROSS
THE REGION. THE NEXT THREE DAYS SHOULD SHOW A CONTINUED DRYING TREND
WITH TEMPERATURES REMAINING NEAR NORMAL.

LOW PRESSURE SYSTEM CONTINUES TO MOVE TOWARDS CALIFORNIA AND WILL BE
OVER NORTHERN CALIFORNIA BY SATURDAY MORNING. ALONG WITH IT HIGH
PRESSURE WILL BUILD OVER SOUTHERN CALIFORNIA AND ARIZONA THUS
KEEPING THE REGION DRY. BY TUESDAY A LONGWAVE TROUGH WILL DEVELOP
AND SWEEP OVER THE DESERT SOUTHWEST.

&&

.AVIATION...
ENOUGH MOISTURE REMAINS IN PLACE TO WARRANT A CONTINUED SLIGHT
CHANCE OF THUNDERSTORMS TODAY...WITH THE GREATEST THREAT ONCE AGAIN
IN SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA. THUNDERSTORM ACTIVITY
IS EXPECTED TO REMAIN ISOLATED...SO DID NOT MENTION IN TAFS...BUT
AMENDMENTS WILL BE ISSUED AS NECESSARY. THE BEST TIME FRAME FOR
THUNDERSTORMS WILL BE 21 TO 01 UTC...WITH THE GREATEST THREAT STRONG
GUSTY WINDS AND BRIEF REDUCTIONS IN VISIBILITIES.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THE THREAT FOR ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE END
OF THE WEEK ACROSS THE LOWER COLORADO RIVER VALLEY AND SE CA. DRIER
AIR WILL MOVE WEST TO EAST ACROSS THE DESERT SOUTHWEST THIS WEEKEND
AS AN AREA OF LOW PRESSURE MOVES THROUGH THE GREAT BASIN. ALTHOUGH
WINDS ARE EXPECTED TO REMAIN BELOW CRITICAL THRESHOLDS...BREEZY
CONDITIONS MAY DEVELOP THIS WEEKEND...POSSIBLY BECOMING WINDY EARLY
NEXT WEEK AS A STRONG PACIFIC LOW PRESSURE SYSTEM SLIDES THROUGH THE
NORTHERN ROCKIES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...WATERS
AVIATION...ROGERS
FIRE WEATHER...WANEK/HIRSCH

000
FXUS65 KTWC 182110
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
210 PM MST THU SEP 18 2008

.SYNOPSIS...ENOUGH MOISTURE WILL REMAIN ACROSS THE AREA FOR A SLIGHT
CHANCE OF AFTERNOON AND EARLY EVENING THUNDERSTORMS WELL WEST AND
SOUTH OF TUCSON TODAY. A COUPLE OF SYSTEMS PASSING THROUGH THE
WESTERN UNITED STATES THIS WEEKEND AND BY THE MIDDLE OF NEXT WEEK
WILL BRUSH NORTHERN ARIZONA. THESE SYSTEMS COULD BRING SOME SHOWERS
AS FAR SOUTH AS THE WHITE MOUNTAINS...BUT OVERALL THEY WILL HAVE
VERY LITTLE IMPACT ON THE WEATHER ACROSS SOUTHEAST ARIZONA. EXPECT
NEAR NORMAL DAYTIME HIGH TEMPERATURES THROUGH NEXT WEEK.

&&

.DISCUSSION...AFTERNOON TEMPERATURES A SMIDGE WARMER THAN FORECAST
WITH SURFACE DEWPOINTS IN THE 40S TO LOWER 50S. MINIMAL MOISTURE
AROUND TO SUPPORT ISOLATED THUNDERSTORMS...MAINLY NEAR THE HIGHER
TERRAIN. ACTIVITY WILL RAPIDLY DIMINISH AFTER THE SETTING SUN WHICH
WILL LEAD TO A CLEAR/MOSTLY CLEAR NIGHT. OVERNIGHT LOW TEMPERATURES
WILL BE AT OR A SMIDGE BELOW NORMAL. UPPER RIDGE AMPLIFYING OVER
THE STATE FRIDAY WITH DAYTIME TEMPERATURES SIMILAR TO TODAY. STILL
ENOUGH MOISTURE AROUND FOR A SLIGHT CHANCE OF STORMS EAST AND SOUTH
OF TUCSON. THE STORM SYSTEM CURRENTLY OFF THE OREGON/NORTHERN
CALIFORNIA COAST WILL MOVE THROUGH THE GREAT BASIN/NORTHERN ROCKIES
ON SATURDAY. MODELS ARE NOW A BIT FURTHER NORTH THAN PREVIOUS RUNS
WILL ONLY IMPACT TO SOUTHEAST ARIZONA WILL BE A SLIGHT CHANCE OF
STORMS IN THE WHITE MOUNTAINS.

GENERAL TROFINESS OVER THE AREA SUNDAY INTO EARLY NEXT WEEK THEN
STRONG RIDGE BUILDS OVER THE AREA DURING LATER HALF ON NEXT WEEK.

&&

.AVIATION...SCATTERED AFTERNOON AND EVENING CLOUDS THIS AFTERNOON
AND EVENING WITH ISOLATED SHOWERS OR THUNDERSTORMS WEST...SOUTH AND
EAST OF TUCSON. WINDS ARE EXPECTED TO BE DIURNAL IN NATURE WITH THE
EXCEPTION OF LOCALIZED WIND GUSTS TO 30 KTS NEAR THUNDERSTORMS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

WEATHER.GOV/TUCSON

000
FXUS65 KPSR 181724
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1020 AM MST THU SEP 18 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...
RESIDUAL MONSOONAL MOISTURE WILL RESULT IN ISOLATED THUNDERSTORMS
ACROSS THE SOUTHWEST DESERTS THROUGH THE END OF THE WEEK. DRIER AIR
WILL MOVE INTO THE REGION THIS WEEKEND AS AN AREA OF LOW PRESSURE
SETTLES ACROSS THE PACIFIC NORTHWEST. THE DRY CONDITIONS WILL
CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR RAIN...EVEN ACROSS THE
HIGHER TERRAIN EAST OF PHOENIX.

&&

.DISCUSSION...
VIS SATELLITE SHOWS MORE GULF OF CALIFORNIA MOISTURE STREAMING INTO
THE COLORADO RIVER VALLEY. DEW PTS REMAIN ELEVATED IN THE REGION
WITH VALUES INTO THE LOW 70S STRETCHING FROM YUMA NORTHEAST TO GILA
BEND. THEREFORE WE WILL LIKELY SEE SHOWERS AND THUNDERSTORMS TO FIRE
OFF AGAIN TODAY...ESPECIALLY ACROSS THE COLORADO RIVER VALLEY.
GUIDANCE IS SHOWING A SLIGHT UPTICK IN MAX TEMPS ACROSS THE REGION
FOR NEXT FEW DAYS WITH MOST AREAS BREAKING THE CENTURY MARK. MAX
TEMPS WERE ADJUSTED ACCORDINGLY.

06Z GFS SHOWED A SIGNIFICANT TROUGH DEVELOPING ACROSS THE GREAT
BASIN BY TUES MORN AND THE 12Z RUN NOW PICKED IT UP AS
WELL...ALTHOUGH WITH LESS AMPLITUDE. ECMWF ALSO SHOWS THE TROUGH BUT
IS LESS PROGRESSIVE...WITH IT PASSING THE REGION ON WEDNESDAY. THIS
MAY RESULT IN A FEW HIGHER TERRAIN SHOWERS TUES-WED BUT STILL
KEEPING POPS LOW DUE TO LOWER CONFIDENCE.

PREVIOUS DISCUSSION...
TODAY...PATTERN WILL AMPLIFY TODAY AS A STRONG LOW PRESSURE SYSTEM
APPROACHES THE WEST COAST. DOWNSTREAM RIDGING ACROSS THE
INTERMOUNTAIN WEST WILL RESULT IN INCREASED THICKNESSES WITH
TEMPERATURES GENERALLY A FEW DEGREES WARMER THAN THOSE YESTERDAY.
WILL SHOOT FOR A HIGH OF 99 DEGREES IN PHOENIX...WHICH ALSO HAPPENS
TO BE THE AVERAGE MAX FOR THE DATE. H7 FLOW WILL REMAIN ANTICYCLONIC
WITH MEXICAN MOISTURE CONTINUING TO ADVECT NORTHWARD UP THE LOWER
COLORADO RIVER VALLEY. CONDITIONS ALOFT NOT EXACTLY CONDUCIVE FOR
CONVECTION...THOUGH SUFFICIENT MOISTURE IN THE SOUTHWEST DESERTS
WILL AGAIN PRODUCE ENOUGH CAPE TO GENERATE ISOLATED LATE
AFTERNOON/EARLY EVENING THUNDERSTORMS.

FRI-SUN...AFOREMENTIONED LOW PRESSURE SYSTEM WILL BECOME NEGATIVELY
TILTED WHILE SLIDING EASTWARD THROUGH THE GREAT BASIN. IN ITS
WAKE...ZONAL FLOW WILL BECOME ESTABLISHED ACROSS THE DESERT
SOUTHWEST. INCREASING WESTERLY COMPONENT TO THE LOW-LEVEL FLOW
SHOULD HELP SCOUR OUT ANY REMAINING MOISTURE ACROSS THE DESERTS
WHILE ADVECTING IT NORTHEASTWARD TOWARDS THE FOUR CORNERS. WARMING
TREND WILL CONTINUE...WITH MAX TEMPERATURES PEAKING SAT OR SUN
AROUND 100 DEGREES IN PHOENIX.

EXTENDED...LATEST 00Z GFS/ECMWF IN GOOD AGREEMENT THAT THE WESTERN
CONUS TROUGH WILL DEEPEN AND SLIDE EASTWARD INTO THE PLAINS.
MERIDIONAL EXTENT OF THE TROUGH AND SUBSEQUENT MOISTURE ADVECTION
MON-WED ACROSS EASTERN AZ MAY BE SOMEWHAT OVERDONE BY THE GFS. DRIER
ECMWF SEEMS LIKE THE MORE LIKELY SCENARIO...TAKING INTO ACCOUNT THE
INCREASINGLY DRY CLIMATOLOGY. MAX TEMPS GENERALLY LOOK TO BE NEAR
NORMAL...WITH THE COOLEST TEMPS OCCURRING TUE BEHIND THE PASSAGE OF
THE TROUGH.

&&

.AVIATION...
ENOUGH MOISTURE REMAINS IN PLACE TO WARRANT A CONTINUED SLIGHT
CHANCE OF THUNDERSTORMS TODAY...WITH THE GREATEST THREAT ONCE AGAIN
IN SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA. THUNDERSTORM ACTIVITY
IS EXPECTED TO REMAIN ISOLATED...SO DID NOT MENTION IN TAFS...BUT
AMENDMENTS WILL BE ISSUED AS NECESSARY. THE BEST TIME FRAME FOR
THUNDERSTORMS WILL BE 21 TO 01 UTC...WITH THE GREATEST THREAT STRONG
GUSTY WINDS AND BRIEF REDUCTIONS IN VISIBILITIES.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THE THREAT FOR ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE END
OF THE WEEK ACROSS THE LOWER COLORADO RIVER VALLEY AND SE CA. DRIER
AIR WILL MOVE WEST TO EAST ACROSS THE DESERT SOUTHWEST THIS WEEKEND
AS AN AREA OF LOW PRESSURE MOVES THROUGH THE GREAT BASIN. ALTHOUGH
WINDS ARE EXPECTED TO REMAIN BELOW CRITICAL THRESHOLDS...BREEZY
CONDITIONS MAY DEVELOP THIS WEEKEND...POSSIBLY BECOMING WINDY EARLY
NEXT WEEK AS A STRONG PACIFIC LOW PRESSURE SYSTEM SLIDES THROUGH THE
NORTHERN ROCKIES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...WATERS
AVIATION...ROGERS
FIRE WEATHER...WANEK/HIRSCH

000
FXUS65 KTWC 181601
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
900 AM MST THU SEP 18 2008

.SYNOPSIS...ENOUGH MOISTURE WILL REMAIN ACROSS THE AREA FOR A SLIGHT
CHANCE OF AFTERNOON AND EARLY EVENING THUNDERSTORMS WELL WEST AND
SOUTH OF TUCSON TODAY. A COUPLE OF SYSTEMS PASSING THROUGH THE
WESTERN UNITED STATES THIS WEEKEND AND BY THE MIDDLE OF NEXT WEEK
WILL BRUSH NORTHERN ARIZONA. THESE SYSTEMS COULD BRING SOME SHOWERS
AS FAR SOUTH AS THE WHITE MOUNTAINS...BUT OVERALL THEY WILL HAVE
VERY LITTLE IMPACT ON THE WEATHER ACROSS SOUTHEAST ARIZONA. EXPECT
NEAR NORMAL DAYTIME HIGH TEMPERATURES THROUGH NEXT WEEK.

&&

.DISCUSSION...A SUNNY SKY PREVAILED THIS MORNING ACROSS SOUTHEAST
ARIZONA. A FEW CUMULUS CLOUDS WILL BE DEVELOPING OVER THE HIGHER
TERRAIN THROUGH THE REMAINDER OF THIS MORNING INTO THIS AFTERNOON.
STILL ENOUGH MOISTURE AROUND TO SUPPORT THUNDERSTORM DEVELOPMENT
WEST AND SOUTH OF TUCSON AND IN THE WHITE MOUNTAINS. HIGHS TODAY
WILL BE NEAR NORMAL.

&&

.AVIATION...SOME AFTERNOON AND EVENING CLOUDS TODAY WITH A SLIGHT
CHANCE OF A SHOWER OR THUNDERSTORM WELL WEST AND SOUTH OF TUCSON.
WINDS ARE EXPECTED TO BE DIURNAL IN NATURE WITH THE EXCEPTION OF
LOCALIZED WIND GUSTS TO 30 KTS NEAR THUNDERSTORMS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

WEATHER.GOV/TUCSON

000
FXUS65 KPSR 181338
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
640 AM MST THU SEP 18 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.UPDATE...UPDATED AVIATION AND FIRE WX DISCUSSION.

.SYNOPSIS...
RESIDUAL MONSOONAL MOISTURE WILL RESULT IN ISOLATED THUNDERSTORMS
ACROSS THE SOUTHWEST DESERTS THROUGH THE END OF THE WEEK. DRIER AIR
WILL MOVE INTO THE REGION THIS WEEKEND AS AN AREA OF LOW PRESSURE
SETTLES ACROSS THE PACIFIC NORTHWEST. THE DRY CONDITIONS WILL
CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR RAIN...EVEN ACROSS THE
HIGHER TERRAIN EAST OF PHOENIX.

&&

.DISCUSSION...
TODAY...PATTERN WILL AMPLIFY TODAY AS A STRONG LOW PRESSURE SYSTEM
APPROACHES THE WEST COAST. DOWNSTREAM RIDGING ACROSS THE
INTERMOUNTAIN WEST WILL RESULT IN INCREASED THICKNESSES WITH
TEMPERATURES GENERALLY A FEW DEGREES WARMER THAN THOSE YESTERDAY.
WILL SHOOT FOR A HIGH OF 99 DEGREES IN PHOENIX...WHICH ALSO HAPPENS
TO BE THE AVERAGE MAX FOR THE DATE. H7 FLOW WILL REMAIN ANTICYCLONIC
WITH MEXICAN MOISTURE CONTINUING TO ADVECT NORTHWARD UP THE LOWER
COLORADO RIVER VALLEY. CONDITIONS ALOFT NOT EXACTLY CONDUCIVE FOR
CONVECTION...THOUGH SUFFICIENT MOISTURE IN THE SOUTHWEST DESERTS
WILL AGAIN PRODUCE ENOUGH CAPE TO GENERATE ISOLATED LATE
AFTERNOON/EARLY EVENING THUNDERSTORMS.

FRI-SUN...AFOREMENTIONED LOW PRESSURE SYSTEM WILL BECOME NEGATIVELY
TILTED WHILE SLIDING EASTWARD THROUGH THE GREAT BASIN. IN ITS
WAKE...ZONAL FLOW WILL BECOME ESTABLISHED ACROSS THE DESERT
SOUTHWEST. INCREASING WESTERLY COMPONENT TO THE LOW-LEVEL FLOW
SHOULD HELP SCOUR OUT ANY REMAINING MOISTURE ACROSS THE DESERTS
WHILE ADVECTING IT NORTHEASTWARD TOWARDS THE FOUR CORNERS. WARMING
TREND WILL CONTINUE...WITH MAX TEMPERATURES PEAKING SAT OR SUN
AROUND 100 DEGREES IN PHOENIX.

EXTENDED...LATEST 00Z GFS/ECMWF IN GOOD AGREEMENT THAT THE WESTERN
CONUS TROUGH WILL DEEPEN AND SLIDE EASTWARD INTO THE PLAINS.
MERIDIONAL EXTENT OF THE TROUGH AND SUBSEQUENT MOISTURE ADVECTION
MON-WED ACROSS EASTERN AZ MAY BE SOMEWHAT OVERDONE BY THE GFS. DRIER
ECMWF SEEMS LIKE THE MORE LIKELY SCENARIO...TAKING INTO ACCOUNT THE
INCREASINGLY DRY CLIMATOLOGY. MAX TEMPS GENERALLY LOOK TO BE NEAR
NORMAL...WITH THE COOLEST TEMPS OCCURRING TUE BEHIND THE PASSAGE OF
THE TROUGH.

&&

.AVIATION...
THERE IS A 5-20% CHANCE OF SHOWERS AND THUNDERSTORMS TODAY ACROSS
THE REGION...WITH THE GREATEST THREAT OUT WEST OVER THE
KYUM/KBLH/KIPL TAF SITES. AT THIS TIME...FORECAST CONFIDENCE REMAINS
TOO LOW TO INCLUDE THE MENTION OF TS IN THE TAF/S. THE BEST TIME
FRAME FOR THUNDERSTORMS WILL BE 22 TO 01 UTC...WITH THE GREATEST
THREAT STRONG GUSTY WINDS AND BRIEF REDUCTIONS IN VISIBILITIES.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THE THREAT FOR ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE END
OF THE WEEK ACROSS THE LOWER COLORADO RIVER VALLEY AND SE CA. DRIER
AIR WILL MOVE WEST TO ACROSS THE DESERT SOUTHWEST THIS WEEKEND AS AN
AREA OF LOW PRESSURE MOVES THROUGH THE GREAT BASIN. ALTHOUGH WINDS
ARE EXPECTED TO REMAIN BELOW CRITICAL THRESHOLDS...BREEZY CONDITIONS
MAY DEVELOP THIS WEEKEND...POSSIBLY BECOMING WINDY EARLY NEXT WEEK
AS A STRONG PACIFIC LOW PRESSURE SYSTEM SLIDES THROUGH THE NORTHERN
ROCKIES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
AVIATION...WANEK
FIRE WEATHER...WANEK/HIRSCH

000
FXUS65 KFGZ 181035
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
335 AM MST THU SEP 18 2008

.SYNOPSIS...EXPECT PARTLY CLOUDY SKIES AND SEASONABLE TEMPERATURES
THROUGH FRIDAY...ALONG WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
DRIER WESTERLY FLOW WILL DEVELOP OVER ARIZONA BY THE WEEKEND. THIS
WILL SUBSTANTIALLY DECREASE THE CHANCE OF SHOWERS BY SATURDAY AND
SUNDAY.

&&

.DISCUSSION...DECENT BOUNDARY LAYER MOISTURE REMAINS ACROSS THE
REGION WITH PW VALUES A BIT ABOVE NORMAL FOR THIS TIME OF YEAR.
FORCING REMAINS WEAK AT BEST...WITH SOME CAPPING EVIDENT AT THE MID
LEVELS OF THE SOUNDINGS TODAY AND FRIDAY. THIS SPELLS LOW-END POPS
AND LOW QPF VALUES FOR THE NEXT FEW DAYS. A TROUGH MOVES THROUGH
UTAH OVER THE WEEKEND WITH DRIER AIR MOVING INTO ARIZONA. THIS WILL
DECREASE POPS TO NEAR ZERO...WITH A SLIGHT INCREASE IN TEMPERATURES.
SOME MOISTURE MAY MOVE INTO THE EASTERN PORTIONS OF THE STATE EARLY
NEXT WEEK...BUT THIS WILL LIKELY BE ANOTHER LOW-END EVENT.

&&

.AVIATION...FOR THE 12Z PACKAGE...ISOLATED THUNDERSTORMS ARE
EXPECTED TO DEVELOP AFTER 18Z OVER THE HIGHER TERRAIN...DRIFTING
EASTWARD THROUGH EARLY EVENING. VFR CONDITIONS WILL PREVAIL...
ALTHOUGH A FEW STORMS COULD PRODUCE MVFR VSBY...AND GUSTY WINDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.

SATURDAY THROUGH MONDAY...SOUTHWEST FLOW WILL INCREASE AHEAD OF A
SERIES OF WEAK TROUGHS PASSING NORTH OF THE STATE. EXPECT NEAR
NORMAL TEMPERATURES...DAYTIME HUMIDITIES IN THE 20-30 PERCENT
RANGE...AND AFTERNOON SOUTHWEST WINDS OF 10-15 MPH. THERE IS ONLY A
SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE HIGHER TERRAIN.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

$$

PUBLIC...............PETERSON
AVIATION/FIRE WX.....JJ

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.

000
FXUS65 KTWC 180918
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
217 AM MST THU SEP 18 2008

.SYNOPSIS...ENOUGH MOISTURE WILL REMAIN ACROSS THE AREA FOR A SLIGHT
CHANCE OF AFTERNOON AND EARLY EVENING THUNDERSTORMS WELL WEST AND
SOUTH OF TUCSON TODAY. A COUPLE OF SYSTEMS PASSING THROUGH THE
WESTERN UNITED STATES THIS WEEKEND AND BY THE MIDDLE OF NEXT WEEK
WILL BRUSH NORTHERN ARIZONA. THESE SYSTEMS COULD BRING SOME SHOWERS
AS FAR SOUTH AS THE WHITE MOUNTAINS...BUT OVERALL THEY WILL HAVE
VERY LITTLE IMPACT ON THE WEATHER ACROSS SOUTHEAST ARIZONA. EXPECT
NEAR NORMAL DAYTIME HIGH TEMPERATURES THROUGH NEXT WEEK.

&&

.DISCUSSION...WEATHER OBSERVATIONS AND THE LATEST MODEL RUNS
SUGGESTED THAT ENOUGH MOISTURE REMAINED IN PLACE ACROSS SOUTHWEST
ARIZONA AND ALONG THE RIM INTO THE WHITE MOUNTAINS TO SUPPORT
THUNDERSTORMS THERE AGAIN TODAY. OTHERWISE...A WEAK RIDGE OF HIGH
PRESSURE AMPLIFIES A BIT OVER THE REGION TODAY AS A SYSTEM
APPROACHES NORTHERN CALIFORNIA AND OREGON. THIS SYSTEM WAS PROGGED
TO REMAIN WELL NORTH OF THE AREA AS IT TRACKS EAST THROUGH THE
NORTHERN ROCKIES. DO NOT EXPECT THIS SYSTEM TO IMPACT OUR WEATHER
THIS FAR SOUTH. ALTHOUGH...SOME LINGERING MOISTURE COMBINED WITH
DAYTIME HEATING COULD STILL RESULT IN SHOWERS ALONG THE RIM INTO THE
WHITE MOUNTAINS THIS WEEKEND. GFS MODEL SHOWED A SIMILAR SECONDARY
SYSTEM ENTERING THE PACIFIC NORTHWEST SUNDAY AND DIGGING A BIT
FARTHER SOUTH THAN THE FIRST SYSTEM BY TUESDAY. THE GFS SUGGESTED
THAT THE TAIL END OF THIS SYSTEM WILL PASS THROUGH ARIZONA BRINGING
A CHANCE OF SHOWERS OR THUNDERSTORMS TO NORTHERN AND EAST-CENTRAL
SECTIONS OF THE STATE TUESDAY INTO WEDNESDAY OF NEXT WEEK.
OVERALL...THE CHANCE OF THUNDERSTORMS WILL BE RATHER LOW THIS
FORECAST PERIOD WITH DAYTIME HIGHS ONLY FLUCTUATING A DEGREE OR TWO
EACH DAY.

&&

.AVIATION...SOME AFTERNOON AND EVENING CLOUDS TODAY WITH A SLIGHT
CHANCE OF A SHOWER OR THUNDERSTORM WELL WEST AND SOUTH OF TUCSON.
WINDS ARE EXPECTED TO BE DIURNAL IN NATURE WITH THE EXCEPTION OF
LOCALIZED WIND GUSTS TO 30 KTS NEAR THUNDERSTORMS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

$$

WEATHER.GOV/TUCSON

000
FXUS65 KPSR 180853
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
150 AM MST THU SEP 18 2008

SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...
RESIDUAL MONSOONAL MOISTURE WILL RESULT IN ISOLATED THUNDERSTORMS
ACROSS THE SOUTHWEST DESERTS THROUGH THE END OF THE WEEK. DRIER AIR
WILL MOVE INTO THE REGION THIS WEEKEND AS AN AREA OF LOW PRESSURE
SETTLES ACROSS THE PACIFIC NORTHWEST. THE DRY CONDITIONS WILL
CONTINUE NEXT WEEK WITH LITTLE CHANCE FOR RAIN...EVEN ACROSS THE
HIGHER TERRAIN EAST OF PHOENIX.

&&

.DISCUSSION...
TODAY...PATTERN WILL AMPLIFY TODAY AS A STRONG LOW PRESSURE SYSTEM
APPROACHES THE WEST COAST. DOWNSTREAM RIDGING ACROSS THE
INTERMOUNTAIN WEST WILL RESULT IN INCREASED THICKNESSES WITH
TEMPERATURES GENERALLY A FEW DEGREES WARMER THAN THOSE YESTERDAY.
WILL SHOOT FOR A HIGH OF 99 DEGREES IN PHOENIX...WHICH ALSO HAPPENS
TO BE THE AVERAGE MAX FOR THE DATE. H7 FLOW WILL REMAIN ANTICYCLONIC
WITH MEXICAN MOISTURE CONTINUING TO ADVECT NORTHWARD UP THE LOWER
COLORADO RIVER VALLEY. CONDITIONS ALOFT NOT EXACTLY CONDUCIVE FOR
CONVECTION...THOUGH SUFFICIENT MOISTURE IN THE SOUTHWEST DESERTS
WILL AGAIN PRODUCE ENOUGH CAPE TO GENERATE ISOLATED LATE
AFTERNOON/EARLY EVENING THUNDERSTORMS.

FRI-SUN...AFOREMENTIONED LOW PRESSURE SYSTEM WILL BECOME NEGATIVELY
TILTED WHILE SLIDING EASTWARD THROUGH THE GREAT BASIN. IN ITS
WAKE...ZONAL FLOW WILL BECOME ESTABLISHED ACROSS THE DESERT
SOUTHWEST. INCREASING WESTERLY COMPONENT TO THE LOW-LEVEL FLOW
SHOULD HELP SCOUR OUT ANY REMAINING MOISTURE ACROSS THE DESERTS WHILE
ADVECTING IT NORTHEASTWARD TOWARDS THE FOUR CORNERS. WARMING TREND
WILL CONTINUE...WITH MAX TEMPERATURES PEAKING SAT OR SUN AROUND 100
DEGREES IN PHOENIX.

EXTENDED...LATEST 00Z GFS/ECMWF IN GOOD AGREEMENT THAT THE WESTERN
CONUS TROUGH WILL DEEPEN AND SLIDE EASTWARD INTO THE PLAINS.
MERIDIONAL EXTENT OF THE TROUGH AND SUBSEQUENT MOISTURE ADVECTION
MON-WED ACROSS EASTERN AZ MAY BE SOMEWHAT OVERDONE BY THE GFS. DRIER
ECMWF SEEMS LIKE THE MORE LIKELY SCENARIO...TAKING INTO ACCOUNT THE
INCREASINGLY DRY CLIMATOLOGY. MAX TEMPS GENERALLY LOOK TO BE NEAR
NORMAL...WITH THE COOLEST TEMPS OCCURRING TUE BEHIND THE PASSAGE OF
THE TROUGH.

&&

.AVIATION...
SOUTH CENTRAL AZ INCLUDING KPHX AND KIPL...
MOSTLY CLEAR SKIES WITH LIGHT WIND EXPECTED THROUGH AT LEAST 03Z FRI.

SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KBLH...KIPL...AND KNYL...
TIL 18Z THU...SCT CLOUDS AOA 12 THSD MSL WITH LIGHT WIND. AFT 18Z
THU...SCT CLOUDS BASED NEAR 8 THSD MSL WITH OCNL BKN LAYERS ABOVE.
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS AREA WIDE THROUGH 03Z
FRI. LIGHT WIND..EXCEPT VRBL GUSTY THUNDERSTORM WINDS TO 30 KNOTS
UNTIL 03Z.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THE THREAT FOR ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE END
OF THE WEEK ACROSS THE LOWER COLORADO RIVER VALLEY AND SE CA. DRIER
AIR WILL MOVE WEST TO ACROSS THE DESERT SOUTHWEST THIS WEEKEND AS AN
AREA OF LOW PRESSURE MOVES THROUGH THE GREAT BASIN. ALTHOUGH WINDS
ARE EXPECTED TO REMAIN BELOW CRITICAL THRESHOLDS...BREEZY CONDITIONS
MAY DEVELOP THIS WEEKEND...POSSIBLY BECOMING WINDY EARLY NEXT WEEK
AS A STRONG PACIFIC LOW PRESSURE SYSTEM SLIDES THROUGH THE NORTHERN
ROCKIES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
AVIATION...VASQUEZ
FIRE WEATHER...HIRSCH