000
FXPQ60 PGUM 200812
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
612 PM CHST TUE JAN 20 2009

.SYNOPSIS...
PGUA WSR-88D SHOWS NO SHOWERS IN THE MARIANAS WATERS. IR
SATELLITE SHOWS A RATHER THICK LAYER OF BLOW OFF CIRRUS WHICH IS
GIVING A DECIDEDLY MOSTLY CLOUDY LOOK TO LOCAL SKIES.

&&

.DISCUSSION...
GFS40 AND UKMET MODELS SEEM TO KEEP THE MARIANAS FIRMLY NEAR OR
UNDER THE SUBTROPICAL RIDGE. DEEP TROPICAL MOISTURE STAYS TO THE
SOUTH WHILE THE SHEAR LINES AND MID-LATITUDE MOISTURE STAY TO THE
NORTH. EVEN THE ECMWF-HIRES IS ON A RELATIVE DRY KICK AS IT FAILS
TO GENERATE ANY QPF VALUE HIGHER THAN 0.33 INCHES...WHICH IS
QUITE UNUSUAL. NEITHER DOES NOGAPS SHOW ANY RAIN TO SPEAK OF
THROUGH DAY 7.

CURRENT FORECAST PACKAGE HAS THE MOSTLY CLOUDY WITH BASICALLY NO
RAIN SCENARIO HANDLED ALREADY SO ONLY MADE MINIMAL TWEAKS. UPPED
CLOUDINESS TONIGHT THROUGH WEDNESDAY NIGHT. LOWERED POPS EVEN
FURTHER THE NEXT FEW PERIODS. OTHERWISE...NO CHANGES NEEDED.

&&

.EASTERN MICRONESIA...
IR IMAGERY FROM THE LAST 24 HOURS DEPICTS ACTIVE BUT WEAKER
TRADE-WIND CONVERGENCE ZONE REMAINING NEARLY STATIONARY AT AROUND
4N. THIS KEEPS IT SOUTH OF POHNPEI TO SOUTH OF MAJURO. HOWEVER...
DEEP CONVECTION IS JUST A FEW MILES SOUTH OF KOSRAE WITH A FINE
DELINEATION BETWEEN SCATTERED SHOWERS AND PARTLY CLOUDY SKIES.
LAST VISIBLE IMAGES INDICATE THAT SHOWERS WILL LIKELY HOLD OFF AT
LEAST UNTIL TOMORROW MORNING. MAY HAVE TO BRING SCATTERED WORDING
INTO THE FORECAST EARLIER THAN ANTICIPATED FOR KOSRAE. MODELS
INDICATE CONVERGENCE ZONE WILL WOBBLE CLOSER TO MAJURO BY
THURSDAY NIGHT ALLOWING FOR INCREASED PRECIP.

SUBSTANTIAL TRADE-WIND SWELL CONTINUES TO AFFECT KOSRAE AND
POHNPEI. HIGH SURF ADVISORY REMAINS IN PLACE FOR BOTH LOCATIONS.
MAJURO WILL LIKELY NEED ADVISORY ISSUANCE WITH STEADILY
INCREASING SURF THROUGHOUT THE EVENING.

&&

.WESTERN MICRONESIA...
VISIBLE SATELLITE IMAGERY SHOWS CONVECTION FLARING UP BETWEEN
KOROR AND YAP ALONG A WEAK TROUGH AND CONVERGENCE ZONE. COVERAGE
OF CONVECTION IS LIMITED TO A NARROW CORRIDOR SO IMPACT TO KOROR
WILL LIKELY BE LIMITED TONIGHT. MODELS IN THIS REGION DO POORLY
THE NEXT FEW DAYS WITH MULTIPLE BULLSEYE CIRCULATIONS SHOWING UP
THURSDAY THROUGH SATURDAY. HOWEVER...CONVERGENCE WILL BE STRONGER
AROUND KOROR WITH YAP EXPERIENCING MORE OF AN INFLUENCE FROM
RIDGING. KEPT ISOLATED WORDING FOR KOROR DUE TO THE INHERENT
UNCERTAINTIES THROUGH THE NEXT SEVERAL DAYS. INCREASED CLOUDS FOR
CHUUK FOR THE NEXT COUPLE OF PERIODS DUE TO CURRENT PROXIMITY OF
SHOWERS TO THE SOUTH.

HIGH SURF ADVISORY FOR CHUUK WAS CONTINUED ALTHOUGH MODELS SHOW A
MARGINAL WIND WAVE SWELL FOR WEDNESDAY AND ESPECIALLY THURSDAY.
EXPIRATION OF ADVISORY FOR THURSDAY MAY BE TIMELY TONIGHT OR
TOMORROW.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...NONE.
&&

$$

STANKO/WILLIAMS

000
FXPQ60 PGUM 200543
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
343 PM CHST TUE JAN 20 2009

.SYNOPSIS...
PGUA WSR-88D SHOWS NO SHOWERS IN THE MARIANAS WATERS. IR SATELLITE
SHOWS A RATHER THICK LAYER OF BLOWOFF CIRRUS WHICH IS GIVING A
DECIDEDLY MOSTLY CLOUDY LOOK TO LOCAL SKIES.

&&

.DISCUSSION...
GFS40 AND UKMET MODELS SEEM TO KEEP THE MARIANAS FIRMLY NEAR OR
UNDER THE SUBTROPICAL RIDGE. TROPICAL MOISTURE STAYS TO THE SOUTH
WHILE THE SHEAR LINES AND MIDLATITUDE MOISTURE STAY TO THE NORTH.
EVEN THE ECMWF-HIRES IS ON A RELATIVE DRY KICK AS IT FAILS TO
GENERATE ANY QPF VALUE HIGHER THAN 0.33 INCHES...WHICH IS QUITE
UNUSUAL. NEITHER DOES NOGAPS SHOW ANY RAIN TO SPEAK OF.

CURRENT FORECAST PACKAGE HAS THE MOSTLY CLOUDY WITH BASICALLY NO
RAIN SCENARIO HANDLED ALREADY SO ONLY MADE MINIMAL TWEAKS. UPPED
CLOUDINESS TONIGHT AND LOWERED POPS EVEN FURTHER THE NEXT FEW
PERIODS. OTHERWISE NO CHANGES NEEDED.

&&

.EASTERN MICRONESIA...
WILL BE UPDATED AROUND 6 PM.

&&

.WESTERN MICRONESIA...
WILL BE UPDATED AROUND 6 PM.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...NONE.
&&

$$

STANKO/WILLIAMS

000
FXPQ60 PGUM 191955
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
555 AM CHST TUE JAN 20 2009

.SYNOPSIS...SATELLITE IMAGERY SHOWS CIRRUS CLOUD COVER ASSOCIATED
WITH CONVECTION SW OF THE MARIANAS REMAINING OVER THE LOCAL AREA.
BENEATH THE UPPER CLOUDS RADAR REVEALS A LINE OF SHALLOW SHOWERS
DRIFTING NORTH PAST ROTA...BUT VERY LITTLE ELSEWHERE. DISTURBANCE
SOUTH OF THE ISLANDS BROUGHT FRESH/STRONG TRADE WINDS TO REGION
SUNDAY AND MONDAY...RAISING SEA HEIGHTS TO 11-12 FT BASED ON IPAN
BUOY...BUT SEAS ARE NOW DOWN TO 10 FT AND EXPECTED TO FALL BELOW
SMALL CRAFT ADVISORY CRITERIA WITHIN THE NEXT COUPLE OF HOURS.
&&

.DISCUSSION...LARGE SCALE WEATHER PATTERN IS STUCK IN A RUT AND
WILL NOT CHANGE SIGNIFICANTLY OVER THE NEXT 5-7 DAYS. WINDS WILL
CONTINUE TO DIMINISH THROUGH WEDNESDAY...AND DENSE CIRRUS CLOUD
COVER IS PREDICTED FOR WED/WED NT TIME FRAME. MOST SIGNIFICANT
FEATURE OBSERVED FROM ANALYSIS OF THE VARIOUS GLOBAL MODEL PROGS
IS THE LACK OF PRECIPITATION FOR REMAINDER OF THE WEEK. RAINFALL
ACCUMULATIONS FOR GFS AND GFS ENSEMBLE FORECAST LESS THAN 0.01 IN
OF RAIN FOR THE MARIANAS THROUGH SAT...AND ECMWF PAINTS A SIMILAR
PICTURE LESS THAN 0.10 IN OF RAINFALL. WHILE MODELS ARE HARDLY
SKILLED AT PREDICTING RANDOM SHOWERS EMBEDDED IN THE TRADE WIND
FLOW...THE MOST LIKELY SCENARIO WILL BE LITTLE OR NO RAIN FOR THE
NEXT SEVERAL DAYS. SO LOWERED POPS TO 10 PCT AND REMOVED ISOL
SHOWERS TONIGHT THROUGH SAT. EXPECT RAINFALL AMT TO BE VERY LIGHT.
&&

.MARINE...WILL LET SCA EXPIRE AT 6 AM AS SCHEDULED BASED ON TREND
FROM IPAN BUOY AND EXPECTATION THAT LIGHTER WINDS TODAY WILL KEEP
WIND WAVES LOWER THAN 7 FT. WW3 GUIDANCE SHOWS AN EAST TRADE-WIND
SWELL AND A NORTHEAST SWELL. NOT ENOUGH OF DIFFERENCE IN DIRECTION
TO JUSTIFY TWO SWELL GROUPS.
&&

.FIRE WEATHER...PROLONGED PERIOD OF DRY WEATHER HAS BEEN MITIGATED
BY CLOUD COVER KEEPING DAILY HIGH TEMPS A BIT LOWER AND RH VALUES
A LITTLE HIGHER. EXPECT KBDI TO CONTINUE ITS STEADY RISE BACK TO
EXTREME RANGE OVER 600 WITH NO WETTING RAIN LIKELY NEXT 3-5 DAYS.
&&

.EASTERN MICRONESIA...PRONOUNCED UPPER-LEVEL DIVERGENCE WILL
CONTINUE TO ENHANCE SHOWER AND THUNDERSTORM ACTIVITY ALONG THE
TRADE-WIND TROUGH. THE HEAVIEST OF WHICH WILL REMAIN POISED OVER
KOSRAE AND ALONG 4N. SCATTERED SHOWERS SHOULD STAY SOUTH OF
POHNPEI AND MAJURO THROUGH THE PERIOD. MODEL GUIDANCE INDICATES
VERY LITTLE OVERALL CHANGE TO THIS PATTERN THROUGH THE WEEK.
HIGH SURF ADVISORY REMAINS IN EFFECT FOR KOSRAE AND POHNPEI DUE
TO LARGE TRADE-WIND GENERATED WAVES AND SWELL. MAJURO WILL LIKELY
NEED AN ADVISORY ISSUANCE SOMETIME THIS EVENING OR TOMORROW.
&&

.WESTERN MICRONESIA...IR SATELLITE SHOWS SPOTTY DEEP CONVECTION
NEAR PALAU AND YAP THIS MORNING. EXPECT THAT COVERAGE WILL REMAIN
ISOLATED FOR THE FORECAST ZONES THOUGH. NO REAL DISCREET WEATHER
SYSTEMS ARE PROGGED TO MOVE INTO THE REGION OVER THE NEXT SEVERAL
DAYS. OVER CHUUK...THE TRADE-WIND TROUGH HAS SAGGED SOUTH OF THE
REGION AND A DRY TRADE-WIND REGIME HAS TAKEN HOLD. GFS AND ECMWF
INDICATE THAT THIS PATTERN WILL REMAIN RELATIVELY UNCHANGED FOR
MUCH OF THE FORECAST PERIOD. HIGH SURF ADVISORY REMAINS IN EFFECT
FOR CHUUK DUE TO LARGE TRADE-WIND GENERATED WAVES AND SWELL.
&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6
AM CHST EARLY THIS MORNING FOR PMZ151>154.

&&

$$

MUNDELL/LEE

000
FXPQ60 PGUM 190701
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
501 PM CHST MON JAN 19 2009

.SYNOPSIS...
PGUA WSR-88D SHOWS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
SOUTHWEST OF THE MARIANAS WATERS ASSOCIATED WITH STRONG TRADE-
WIND CONVERGENCE. WITHIN MARIANAS WATERS...ONLY ISOLATED SHOWERS
ARE MOVING THROUGH THE AREA. FRESH TRADE WINDS WILL GRADUALLY
SLACKEN OVERNIGHT AND INTO TUESDAY.

&&

.DISCUSSION...
GFS40 MODEL CONTINUES TO PAINT A DRY PICTURE...WITH ONLY 0.01
INCHES OF RAIN FOR GUAM TONIGHT THROUGH FRIDAY NIGHT. THE
MARIANAS REMAIN STUCK SOUTH OF THE SHEAR LINES AND NORTH OF THE
DEEP TRADE-WIND CONVECTION. TRADE WINDS ARE EXPECTED TO FRESHEN A
BIT FOR NEXT WEEKEND...PROBABLY AS THE NEXT HIGH PUSHES OUT OF
ASIA. PRETTY MUCH WE SHOULD JUST EXPECT MORE OF THE SAME...SO
JUST EXTENDED SOME GRIDS BUT OVERALL NO CHANGES. PREVIOUS PACKAGE
HAD ALL THESE TRENDS WELL HANDLED.

&&

.MARINE...
DID EXTEND THE SMALL CRAFT ADVISORY. THIS WAS DUE TO IPAN BUOY
DATA THAT CONTINUED TO INDICATE COMBINED SEAS OF AROUND 11 FEET.

&&

.EASTERN MICRONESIA...
SATELLITE SHOWS CONVECTIVE CLOUDS SPREAD ACROSS THE AREA BETWEEN
3N AND 6N WHILE 200 MB ANALYSIS SHOWS SUPPORTING UPPER-LEVEL
DIVERGENCE ESPECIALLY BETWEEN 155E AND 165E. HEAVIEST CONVECTION
IS AFFECTING KOSRAE. MODEL GUIDANCE INDICATES VERY LITTLE OVERALL
CHANGE TO THIS PATTERN THROUGH THE WEEK. STRONGER TRADE WINDS ON
THE NORTH SIDE OF THE CONVERGENCE WILL CONTINUE TO AFFECT OUR
FORECAST POINTS WHILE THE CONVECTIVE ACTIVITY WILL BE FOCUSED
BROADLY ALONG 5N.

HIGH SURF ADVISORY REMAINS IN EFFECT FOR KOSRAE AND POHNPEI DUE
TO LARGE TRADE-WIND GENERATED WAVES AND SWELL. MAJURO WILL LIKELY
NEED AN ADVISORY ISSUANCE SOMETIME ON TUESDAY.

&&

.WESTERN MICRONESIA...
A FEW ADJUSTMENTS WERE MADE TO THE FORECAST. LATEST SATELLITE
SHOWS AREAS OF DEEP CONVECTION CONFIGURED AROUND A POSSIBLE LOW-
LEVEL CIRCULATION CENTROID NEAR 12N138E ASSOCIATED WITH FORMER
INVEST 93W. SOME CONVECTIVE CLOUDS WERE DRIFTING WESTWARD TOWARD
YAP. QUIKSCAT ANALYSIS FROM EARLIER IN THE DAY INDICATED ONLY THE
BASE OF A SURFACE TROUGH THAT EXTENDS FROM 8N135E TO 15N138E. GFS
MODEL GUIDANCE INDICATES THESE AREAS OF CONVECTION WILL ROTATE
NORTHWARD AROUND THE WESTERN LIMB OF THE RIDGE SITUATED OVER THE
WESTERN PACIFIC...WHILE A MORE SEASONAL TRADE-WIND FLOW DEVELOPS
DURING THIS COMING WEEK. CHUUK WILL REMAIN WHERE FRESH NORTHEAST
TRADE WINDS BEGIN TO CONVERGE JUST TO THE NORTH OF THE BAND OF
DEEP CONVECTION THAT HAS BEEN AFFECTING EASTERN MICRONESIA.

HIGH SURF ADVISORY REMAINS IN EFFECT FOR CHUUK DUE TO LARGE
TRADE-WIND GENERATED WAVES AND SWELL.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS
                  UNTIL 6 AM CHST TUESDAY FOR PMZ151>154.

&&

$$

STANKO/SIMPSON

000
FXPQ60 PGUM 181945
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
545 AM CHST MON JAN 19 2009

.SYNOPSIS...
LATEST SATELLITE SHOWS QUITE A BIT OF MID/HIGH CLOUDINESS OVER THE
MARIANAS...BUT RADAR SHOWS ONLY ISOLATED SHOWERS ACTUALLY REACHING
THE SURFACE. RADAR WINDS ARE INDICATED NEAR 35 KT AT TIMES ABOVE
2000 FEET...AND SOME GUSTS TO 25-27 KT ARE BEING REGISTERED AT THE
AIRPORT IN THE LAST HOUR.

&&

.DISCUSSION...
GFS TIME-HEIGHT SHOWS CONSIDERABLE MOISTURE IN THE MID AND UPPER
LEVELS TODAY...THEN DRYING OUT THE NEXT FEW DAYS. BUT THE GFS ALSO
SHOWS A DRIER SUBSIDENT LAYER BETWEEN 850 AND 700 MB THE NEXT FEW
DAYS...AND 12Z SOUNDING VERIFIES THIS. THIS WILL PUT A DAMPER ON
SHOWERS IF IT PERSISTS...BUT THE GFS HAS HAD A DRY BIAS LATELY.
THUS HAVE KEPT ISOLATED SHOWERS IN THE FORECAST FOR NOW. BREEZY
CONDITIONS ON TAP TODAY...BUT WINDS SHOULD SLOWLY DECREASE AS THE
WEEK PROGRESSES.

&&

.MARINE...
SMALL CRAFT ADVY STILL GOOD TODAY...WITH IPAN BUOY SHOWING SEAS
OVER 10 FEET AT TIMES THIS MORNING. BUT SEAS ARE EXPECTED TO FALL
TO 9 FEET TONIGHT AND REMAIN IN THE 8-9 FT RANGE THROUGH MIDWEEK.

&&

.EASTERN MICRONESIA...
NARROW BAND OF CONVECTION CURRENTLY SOUTH OF POHNPEI....AND EXTENDS
EASTWARD OVER KOSRAE THROUGH THE SOUTHERN MARSHALL ISLANDS. GFS AND
ECMWF FOR THE MOST PART INDICATE THAT THIS TRADE-WIND CONVERGENCE
AXIS WILL REMAIN SEMI-STATIONARY THROUGH THE WEEK...SO HAVE KEPT THE
BULK OF SHOWER ACTIVITY SOUTH OF MAJURO AND POHNPEI BUT OVER POHNPEI
THE NEXT COUPLE DAYS. THIS ALIGNS WELL WITH THE CURRENT SATELLITE
AND THE PREVIOUS FORECAST.

HIGH SURF ADVISORY REMAINS IN EFFECT FOR KOSRAE AND POHNPEI DUE TO
LARGE TRADE-WIND GENERATED WAVES AND SWELL. MAJURO WILL LIKELY NEED
AN ADVISORY SOMETIME ON TUESDAY.

&&

.WESTERN MICRONESIA...
MADE MINOR UPDATES TO THE PREVIOUS FORECAST...NOTHING EARTH-
SHATTERING THOUGH. A SURFACE TROUGH NEAR 135E IS THE MAIN FOCUS OF
CONVECTION AROUND YAP THIS MORNING. SIGNS THAT THIS TROUGH WILL
SHARPEN AND CLOSE OFF ARE ALREADY BEGINNING TO SHOW ON THE LATEST
IR. THE GFS ACTUALLY SHOWS THIS HAPPENING BY TUESDAY. ONCE THIS
OCCURS...SHOWERS SHOULD CONSOLIDATE NORTH OF THE FORECAST AREA.
AFOREMENTIONED SWATH OF TRADE-WIND INDUCED SHOWER ACTIVITY WILL
LINGER THE NEXT DAY AT CHUUK BEFORE DRIER CONDITIONS EASE
SOUTHWARD OVER THE REGION.

HIGH SURF ADVISORY REMAINS IN EFFECT FOR CHUUK DUE TO LARGE
TRADE-WIND GENERATED WAVES AND SWELL.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
     6 PM CHST THIS AFTERNOON FOR PMZ151>154.

&&

$$

MIDDLEBROOKE/LEE

000
FXPQ60 PGUM 180657
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
457 PM CHST SUN JAN 18 2009

.SYNOPSIS...
JTWC INVEST AREA 93W IS CURRENTLY PASSING SOUTH OF GUAM NEAR 8N.
TRADE-WIND CONVERGENCE ON THE NORTH SIDE OF THIS SYSTEM IS
GENERATING SCATTERED SHOWERS NORTHWARD TO THE MARINE ZONES JUST
SOUTH OF GUAM. DRIER AIR/RIDGING ARE PUSHING IN FROM THE EAST ON
THE HEELS OF THIS SYSTEM.

&&

.DISCUSSION...
LITTLE CHANGE TO FORECAST. DID KEEP MOSTLY CLOUDY SKIES THROUGH
MONDAY. GFS INDICATES QUITE A BIT OF MOISTURE WILL BE CARRIED
ALOFT OVER THE MARIANAS FROM CONVECTION TO THE SOUTH. WINDS WILL
STAY HIGH THROUGH THE DAY MONDAY AND START TO SUBSIDE MONDAY
NIGHT. THE WINDS WILL DECREASE ONLY SLIGHTLY AS 15 TO 20 MPH IS
EXPECTED THROUGH THE WEEK. A SERIES OF HIGH PRESSURE CENTERS
MOVING ACROSS THE NORTH PACIFIC WILL HELP KEEP WIND SPEEDS UP
THROUGH THE WEEK.

&&

.MARINE...
ONLY A FEW TWEAKS TO THIS FORECAST. DID BOOST INITIAL EAST SWELL
GRIDS TO 5 FEET. IPAN BUOY WAS UP TO 9 FEET THIS AFTERNOON. USING
A 5 FOOT EAST SWELL ALLOWED FOR COMBINED SEAS OF 10 FEET. SEAS
HOVERING AROUND TEN FEET THROUGH MONDAY AFTERNOON WILL PROBABLY
MAINTAIN THE NEED FOR A SMALL CRAFT ADVISORY UNTIL MONDAY NIGHT.

THE EAST SWELL WILL INCREASE TO 6 FEET ON TUESDAY...ALTHOUGH THE
NORTH SWELL AND WIND WAVES WILL DECREASE AT THE SAME TIME.
THUS...A SMALL CRAFT ADVISORY IS NOT EXPECTED AFTER MONDAY NIGHT.

&&

.EASTERN MICRONESIA...
ONLY MINOR CHANGES WERE MADE TO PREVIOUS FORECAST TRENDS.
SATELLITE SHOWS CONVECTIVE CLOUDS SPREAD ACROSS THE AREA MAINLY
ALONG 5N. GFS INITIALIZES THE PATTERN DECENTLY AND INDICATES
FOCUS OF CONVERGENCE WILL DRIFT SLIGHTLY SOUTH WITH HEAVIER
ACTIVITY DEVELOPING IN THE VICINITY OF 150E WHERE SUPPORT FROM
UPPER-LEVEL DIVERGENCE WILL PERSIST THROUGH MOST OF THE COMING
WEEK.

ISSUED HIGH SURF ADVISORY FOR KOSRAE TONIGHT AND POHNPEI FOR
MONDAY BECAUSE OF BUILDING TRADE-WIND GENERATED WAVES. MAJURO
WILL LIKELY NEED AN ADVISORY AS THE WEEK PROGRESSES.

&&

.WESTERN MICRONESIA...
ADJUSTMENTS WERE MADE TO THE PREVIOUS FORECAST BOTH FOR WINDS AND
WEATHER. QUIKSCAT ANALYSIS INDICATES A WEAK LOW-LEVEL CIRCULATION
CENTERED NEAR 5N130E...WITH NEAR-EQUATORIAL TROUGH SOUTHEASTWARD
TO EQ150E. SATELLITE SHOWS SIGNIFICANT CONVECTION SPREAD FROM
WESTERN PARTS OF THE AREA NORTHEASTWARD TO NEAR GUAM AND EASTWARD
TO CHUUK. GFS DOES NOT INITIALIZE THE LOW-LEVEL FLOW IN THIS AREA
VERY WELL. SURGING TRADE WINDS WILL CAUSE WEATHER CONDITIONS TO
BE SHOWERY FOR PALAU AND YAP DURING THE NEXT COUPLE OF DAYS.
SHOWER COVERAGE WILL DECREASE AND TRADE WINDS WILL BECOME LIGHTER
DURING THE SECOND HALF OF THE FORECAST PERIOD. FOR CHUUK...MODEL
GUIDANCE INDICATES MODERATELY STRONG TRADE-WIND CONVERGENCE THAT
HAS CAUSED SHOWERS IN THE VICINITY WILL DRIFT SOUTHWARD BY AROUND
TUESDAY.

ISSUED HIGH SURF ADVISORY FOR CHUUK FOR MONDAY BECAUSE OF
BUILDING TRADE-WIND GENERATED WAVES AND CANCELED HSA FOR KOROR
AND YAP SINCE NORTH SWELLS WERE SUBSIDING.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6
PM CHST MONDAY FOR PMZ151>154.

&&

$$

ZIOBRO/SIMPSON

000
FXPQ60 PGUM 172025
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
625 AM CHST SUN JAN 18 2009

.SYNOPSIS...
RATHER UNEXPECTEDLY...A WEAK DISTURBANCE IS BRINGING SCATTERED
SHOWERS TO THE MARIANAS. RADAR SHOWS MOST OF THE SHOWERS NEAR AND
SOUTH OF GUAM...BUT A FEW HAVE ALSO DEVELOPED NEAR TINIAN/SAIPAN.

&&

.DISCUSSION...
SATELLITE/RADAR TRENDS AGREE WITH GFS IN MOVING SHOWERS OUT LATE
THIS MORNING. AFTER THAT...GFS SHOWS MID-HIGH LEVEL CLOUDINESS
HANGING ON THROUGH TONIGHT...BUT ONLY ISOLATED SHOWERS THE NEXT
FEW DAYS.

&&

.MARINE...
TRADE SURGE WILL ARRIVE THIS MORNING WITH 20 KT WINDS THROUGH
MONDAY. THIS WILL BRING COMBINED SEAS UP TO 10 FEET...RESULTING IN
THE ISSUANCE OF A SMALL CRAFT ADVISORY.

&&

.EASTERN MICRONESIA...
STRONG CONVERGENCE AHEAD OF A FRESH TRADE-WIND SURGE IS TEAMING UP
WITH FAVORABLE WINDS ALOFT TO CREATE A LINE OF CONVECTION ACROSS THE
ENTIRE REGION THIS MORNING. SHOWERS AND POSSIBLE THUNDERSTORMS ARE
LIKELY OVER BOTH MAJURO AND POHNPEI FOR THE NEXT 12 TO 24 HOURS.
ACCORDING TO THE SATELLITE IMAGERY FOR THE PAST 12 HOURS...THE
STRONG TRADES HAVE BEEN STEADILY PRESSING THE CONVECTION SOUTHWARD.
BASED ON THIS TREND...THE HEAVIEST CONVECTION WILL BE LOCATED
ROUGHLY ALONG 4N BY MONDAY NOON. THEREFORE...CONDITIONS OVER MAJURO
AND POHNPEI ARE EXPECTED TO IMPROVE BY EARLY MONDAY MORNING AND
MONDAY NOON RESPECTIVELY. ON THE OTHER HAND...KOSRAE WILL REMAIN
WITHIN THE CONVECTIVE AREA THRU TUESDAY.

BY MIDWEEK...DRIER NORTHEASTERLY TRADES WILL BE WELL ESTABLISHED
ACROSS MAJURO AND POHNPEI WITH FAIR WEATHER. CONVERGENCE ZONE OVER
KOSRAE WILL BE WEAKER BY THEN BUT STILL SUFFICIENT TO MAINTAIN
CLOUDS AND SOME SHOWERS THRU THURSDAY.

TRADE-WIND INDUCED SWELLS AND WIND WAVES WILL CONTINUE TO BUILD THRU
TONIGHT...CAUSING SEAS TO REACH 11 FEET BY MONDAY MORNING. AS A
RESULT...SURF HEIGHTS ALONG EASTERN EXPOSURES ARE EXPECTED TO RISE
ABOVE ADVISORY LEVEL OF 12 FEET FROM CHUUK AND EASTWARD TO MAJURO
BY MONDAY MORNING. A HIGH SURF ADVISORY WILL BE WARRANTED BY THIS
AFTERNOON.

&&

.WESTERN MICRONESIA...
THE LEADING EDGE OF THE FRESH TRADE SURGE MENTIONED ABOVE WILL ALSO
BRING INCLEMENT WEATHER TO CHUUK THRU MONDAY AFTERNOON. THINGS WILL
BEGIN TO QUIET DOWN ON MONDAY EVENING AS DRIER AND STRONGER TRADES
FILTER INTO THE AREA. WITH THE MAIN CONVERGENCE ZONE REMAINING
SOUTH OF THE ISLAND...PARTLY CLOUDY SKIES WILL PREVAIL THRU
MIDWEEK.

AT THE MID TO UPPER LEVELS....DIVERGENCE IS ANTICIPATED TO PERSIST
ACROSS THE WHOLE AREA AT LEAST INTO MIDWEEK. AT THE LOWER LEVELS...
THE NEAR-EQUATORIAL TROUGH IS STILL DOMINATING PALAU WHILE A
TRADE-WIND SURGE INDUCED TROUGH IS APPROACHING YAP. MIXING ALL
THESE INGREDIENTS TOGETHER...SCATTERED CONVECTION WITH OCCASIONAL
HEAVY SHOWERS ARE LIKELY THRU MONDAY NIGHT. AFTERWARD MODELS WITH
GFS TO BE MOST AGGRESSIVE...SEEM TO RETREAT THE NEAR-EQUATORIAL
TROUGH TOO FAST TOWARD THE PHILIPPINES AND ALSO DIMINISH THE TRADE
SURGE TOO RAPIDLY. FOR NOW...HAD KEPT CLOUDINESS WITH A SLIGHT
THREAT FOR THUNDER TOWARD MIDWEEK. FUTURE FORECAST MIGHT NEED TO
UPGRADE SHOWER COVERAGE BASED ON THE STATUS OF THE SYNOPTIC
FEATURES IN THE AREA.

SURF HEIGHTS ALONG NORTH FACING EXPOSURES ON PALAU AND YAP ARE
EXPECTED TO GRADUALLY SUBSIDE BELOW ADVISORY LEVEL BY THIS EVENING.
DAY SHIFT SHOULD BE ABLE TO CANCEL THE HIGH SURF ADVISORY THIS
AFTERNOON.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
     6 PM CHST MONDAY FOR PMZ151>154.

&&

$$

MIDDLEBROOKE/CHAN