AREA FORECAST DISCUSSION

FXUS65 KTWC 051003
 AFDTWC
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE TUCSON AZ
 300 AM MST FRI NOV 5 2004
 
 SOUTHEAST ARIZONA FORECAST DISCUSSION
 
 .SYNOPSIS...THE COMBINATION OF HIGH PRESSURE ALOFT AND SOUTHWEST 
 FLOW AROUND AN AREA OF LOW PRESSURE OVER THE CENTRAL CALIFORNIA 
 COAST WILL CONTINUE THE WARM AND DRY CONDITIONS THROUGH SATURDAY. 
 THE LOW PRESSURE SYSTEM WILL THEN TRACK EAST ACROSS THE REGION LATE 
 IN THE WEEKEND AND EARLY NEXT WEEK...BRINGING COOLER TEMPERATURES... 
 GUSTY WINDS...AND A CHANCE OF SHOWERS. 
 &&
 
 .DISCUSSION...NOT MUCH CHANGE IN THINKING FROM PREVIOUS SHIFTS AS 
 LARGE UPPER LOW CONTINUES TO SPIN OFF THE CENTRAL CALIFORNIA COAST. 
 THE COMBINATION OF HIGH PRESSURE EXTENDING FROM ARIZONA SOUTHEAST 
 ACROSS SOUTHWEST TEXAS/NORTHERN MEXICO AND SOUTHWEST FLOW AROUND THE 
 UPPER LOW WILL CONTINUE TO BRING WARM AND DRY CONDITIONS TO MUCH OF 
 THE REGION INCLUDING SOUTHEAST ARIZONA INTO SATURDAY. ALTHOUGH THE 
 UPPER LOW HAS TAPPED SOME HIGH LEVEL MOISTURE...MOST OF THE CIRRUS 
 CLOUDS ARE OF THE THIN VARIETY AND SHOULD HAVE LITTLE OVERALL EFFECT 
 ON DAYTIME HIGHS. AFTERNOON HIGH READINGS ARE EXPECTED TO BE 4 TO 8 
 DEGREES ABOVE SEASONAL NORMALS TODAY AND SATURDAY. 
 
 BY EARLY SUNDAY THE UPPER LOW BEGINS TO EJECT EASTWARD...WITH THE 
 LATEST TRACK NEAR LAS VEGAS LATE SUNDAY AND ALONG THE ARIZONA/UTAH 
 BORDERS MONDAY. THE SYSTEM WILL THEN MOVE EAST OF THE REGION ALONG  
 THE FRONT RANGE OF THE ROCKIES DURING THE DAY TUESDAY. THIS LATEST 
 RUN WAS A LITTLE FURTHER NORTH WITH THE TRACK AND MOISTURE...AS HAS 
 BEEN THE CASE THE LAST COUPLE OF RUNS. THE MODELS ARE STILL HAVING A 
 DIFFICULT TIME WITH EXACT TRACK AND TIMING...AS IS OFTEN THE CASE 
 WITH CUTOFF LOWS. HOWEVER...EVEN WITH LIMITED MOISTURE (THE MOISTURE 
 FIELD IS CURRENTLY WRAPPED FAIRLY TIGHTLY AROUND THE CENTER OF THE 
 LOW) BEING WELL SOUTH OF THE TRACK THERE WILL STILL BE SUFFICIENT 
 DYNAMICS AND LIFT TO WARRANT SLIGHT CHANCE TO CHANCE POPS WITH THE 
 PASSAGE OF THIS SYSTEM. THE BEST CHANCES FOR PRECIPITATION WILL 
 OCCUR IN THE LATE SUNDAY TO EARLY MONDAY TIME FRAME AND NORTHEAST OF 
 THE TUCSON METRO AREA...ESPECIALLY IN THE WHITE MOUNTAINS. THIS 
 SYSTEM WILL NOT BE A PARTICULARY COLD ONE WITH SNOW LEVELS EXPECTED 
 TO REMAIN ABOVE 7500 FEET...ALTHOUGH TEMPERATURES WILL COOL OFF TO 
 SLIGHTLY BELOW NORMAL BEHIND IT ON MONDAY AND TUESDAY. 
 
 THE MODELS THEN FORECAST ANOTHER LOW TO DIVE SOUTH ALONG THE PACIFIC 
 COAST AND CLOSE OFF ACROSS NORTHERN BAJA DURING THE MIDDLE TO END OF 
 NEXT WEEK. THE MEDIUM RANGE MODEL SOLUTIONS VARY EXTENSIVELY ON THE 
 TRACK OF THIS NEXT SYSTEM...AND THE CONSENSUS AMONG ARIZONA OFFICES 
 WAS TO SHOW A VERY GRADUAL WARMING TREND UNTIL THE MODELS COME MORE 
 IN LINE WITH EACH OTHER.  
 &&
 
 .TWC WATCHES/WARNINGS/ADVISORIES...NONE.
 &&
 
 

 
 ZELL
 

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