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588 FXUS65 KTWC 030925 AFDTWC AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 225 AM MST THU OCT 3 2013 .SYNOPSIS...A TROUGH BRUSHING BY NORTH OF THE AREA WILL BRING SOME BREEZINESS LATER TODAY INTO FRIDAY...ALONG WITH SEVERAL DEGREES OF COOLING FRIDAY INTO SATURDAY. && .DISCUSSION...STILL RATHER DRY WESTERLY FLOW ACROSS SOUTHEAST ARIZONA THIS MORNING...BUT STARTING TO GAIN A SOUTHERLY INFLECTION TO THE FLOW THAT WILL DRAW SOME THIN PATCHES OF MAINLY CIRRUS LEVEL MOISTURE BRUSHING BY FROM THE SOUTH AND EVEN SOME SHALLOW SURFACE DEWPT INCREASES. FURTHER INCREASE IN SOUTHWESTERLY GRADIENT AS A STRONG SYSTEM PUSHES INTO THE REGION WELL NORTH OF US SHOULD SEE A FEW AFTERNOON GUSTS IN WIND PRONE LOCATIONS AND HIGHER ELEVATIONS WITH BREEZY LEVELS IN SPOTS THIS AFTERNOON AND FRIDAY AFTERNOON. OTHERWISE...THE MAIN STORM TRACK IS HIGHER LATITUDE FOR BREEZY CONDITIONS AT TIMES AND A COOLING TREND FRIDAY AND SATURDAY FOR SOUTHEAST ARIZONA. COOLEST OVERNIGHT LOWS BEHIND THE SAGGING TROUGHINESS FOR OUR PART OF THE STATE SATURDAY NIGHT INTO SUNDAY MORNING WITH 40S EAST TO 50S WEST. STRONG BUT SHORT PERIOD RIDGE PHASES IN QUICKLY FROM THE WEST SUNDAY AND MONDAY WITH RAPID BUT PROBABLY BRIEF WARMING TREND. REASONABLE MEASURE OF PREDICTABILITY WITH ECMWF SOLUTION BRINGING ANOTHER TROUGH INTO THE REGION THE FIRST HALF OF NEXT WEEK. POTENTIAL GOOD FOR A DEEPER TRACK THAN ADVERTISED BY GFS OR PARTIAL SPLIT BY THAT POINT WITH GFS ENSEMBLE HINTING AT BETTER STACKING OF RIDGE UPSTREAM. WE`LL START TO TREND TEMPS DOWN A LITTLE AND BLEND IN SOME IDEAS FROM ECMWF OUTPUT AROUND THE MIDDLE OF NEXT WEEK. && .AVIATION...SKC-SCT CLOUDS AT OR ABOVE 20K FT AGL THRU EARLY FRIDAY OR 04/09Z. SURFACE WIND GENERALLY LESS THAN 10 KTS THIS MORNING...THEN SURFACE WIND SWLY-WLY 10-15 KTS WITH GUSTS TO 22 KTS THIS AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...LOW PRESSURE WILL MOVE ACROSS THE CENTRAL ROCKIES AS THE WORK WEEK COMES TO A CLOSE. INCREASED SOUTHWESTERLY TO WESTERLY SURFACE WINDS WILL OCCUR ACROSS SE AZ TODAY AND FRIDAY BUT DRY CONDITIONS WILL PERSIST. COOLING TREND FRIDAY AND SATURDAY...WITH TEMPERATURES SEVERAL DEGREES BELOW AVERAGE BY SATURDAY BEFORE RETURNING TO NEAR SEASONAL NORMALS EARLY NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON MEYER/RASMUSSEN
