AREA FORECAST DISCUSSION

 
 FXUS65 KTWC 140411 AAA
 AFDTWC
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE TUCSON AZ
 910 PM MST THU AUG 13 2009
 
 .SYNOPSIS...DRIER AIR WILL ARRIVE IN SOUTHEAST ARIZONA ON 
 FRIDAY...WITH ONLY ISOLATED SHOWERS POSSIBLE ACROSS THE EASTERN 
 COUNTIES. ANOTHER UNSEASONABLY STRONG TROUGH OF LOW PRESSURE WILL 
 PASS THROUGH THE GREAT BASIN THIS WEEKEND...RESULTING IN ANOTHER 
 DOWNTURN IN THE MONSOON. EXPECT DRY CONDITIONS SATURDAY INTO EARLY 
 NEXT WEEK.
 
 &&
 
 .DISCUSSION...AN UNSEASONABLY MILD DAY FOR A CHANGE...WITH THE MAX 
 TEMP OF 86 AT KTUS THE COOLEST SINCE JUNE 19TH...AND 11 DEGREES 
 BELOW NORMAL. MANY LOCATIONS HELD IN THE 70S TODAY...INCLUDING 
 SIERRA VISTA AT ONLY 74. TEMPERATURES WILL REBOUND QUICKLY TOWARD 
 NORMAL VALUES ON FRIDAY WITH THE HELP OF DRIER AIR ARRIVING...AND 
 INCREASING 850 MB TEMPS/THICKNESSES.
 
 MANY PARTS OF SOUTHEAST ARIZONA RECEIVED BENEFICIAL RAINFALL FROM 
 THIS EVENT...WITH 1-2 INCHES REPORTED AT BISBEE...DOUGLAS...ELGIN...AND 
 CORONADO NATIONAL MONUMENT. MINOR STREET FLOODING WAS OBSERVED FROM 
 STORMS EARLIER IN COCHISE COUNTY. STORMS HAVE SINCE WEAKENED AND 
 MOVED INTO NEW MEXICO. SKIES CLEARING QUICKLY FROM WEST TO 
 EAST...WITH WATER VAPOR IMAGERY SHOWING MUCH DRIER AIR PUNCHING IN 
 FROM THE WEST. 00Z KTWC SOUNDING WAS STILL MOIST AT LAUNCH TIME WITH 
 A PW OF 1.51 INCH...BUT VALUES ARE ALREADY FALLING AND EXPECT THEM 
 TO CONTINUE TO DO SO THE NEXT FEW DAYS. ALREADY SENT UPDATES TO 
 REMOVE POPS AND SKY COVER FOR MOST LOCATIONS FOR THE REST OF TONIGHT.
 
 ANOTHER MAJOR DOWNTURN...IF NOT COMPLETE SHUTDOWN...OF THE MONSOON 
 EXPECTED OVER THE WEEKEND INTO EARLY NEXT WEEK. NEW 00Z NAM MOS HAS 
 POPS NEAR 2-6% FOR MOST LOCATIONS ON FRIDAY. POPS WE HAVE IN THE GRIDS 
 LOOK TOO HIGH AND MIDNIGHT SHIFT WILL HAVE TO CUT THEM BACK QUITE A 
 BIT. PW SHOULD HOLD AROUND AN INCH OR SO...BUT WITH DRIER 
 WEST/NORTHWEST FLOW CAN`T SEE MUCH HAPPENING TOMORROW. MAYBE A FEW 
 BUILDUPS ON THE WHITE MOUNTAINS AND ON THE HIGHER TERRAIN EAST OF 
 TUCSON FRIDAY AFTERNOON. 
 
 YET ANOTHER UNSEASONABLY STRONG TROUGH SWINGS THROUGH THE GREAT 
 BASIN OVER THE WEEKEND WITH THE MONSOON HIGH AGAIN SUPPRESSED TO OUR 
 SOUTH...AND WE ARE LEFT WITH DRY WESTERLY FLOW YET AGAIN. TODAY`S 
 RAIN WAS THE LAST MOST OF US WILL SEE FOR SOME TIME TO COME.
 
 &&
 
 .AVIATION...MOSTLY CLEAR SKIES EXPECTED OVERNIGHT AS DRIER AIR 
 INVADES SOUTHEAST ARIZONA. MOSTLY CLEAR THROUGH 18Z FRIDAY...WITH A 
 FEW CUMULUS ON THE HIGHER TERRAIN EAST OF TUCSON FRIDAY AFTERNOON. 
 ONLY ISOLATED SHRA EXPECTED NEAR THE WHITE MOUNTAINS AND EAST OF 
 TUCSON FRIDAY...WITH TAF SITES EXPECTED TO REMAIN DRY. SURFACE WINDS 
 DIURNALLY DRIVEN AT 5-15 KTS THROUGH FRIDAY. AVIATION DISCUSSION NOT 
 UPDATED FOR TAF AMENDMENTS.
 
 &&
 
 .FIRE WEATHER...A TROUGH OF LOW PRESSURE ACROSS THE WESTERN STATES 
 WILL BRING MUCH DRIER CONDITIONS TO THE AREA STARTING FRIDAY WITH 
 ONLY ISOLATED SHOWERS POSSIBLE NEAR THE WHITE MOUNTAINS AND ON THE 
 HIGHER TERRAIN. WARM DRY WESTERLY FLOW RETURNS WITH NO CHANCES FOR 
 RAIN THIS WEEKEND INTO EARLY NEXT WEEK. THE NEXT CHANCE OF RAINFALL 
 TO BE MAINLY NEAR THE NEW MEXICO BORDER TUESDAY THROUGH THURSDAY.
 
 &&
 
 .TWC WATCHES/WARNINGS/ADVISORIES...NONE.
 
 

 
 TURNER
 
 WEATHER.GOV/TUCSON
 
 
 
 
 
 
 

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