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000 FXUS65 KTWC 032056 AFDTWC AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 155 PM MST FRI OCT 3 2008 .SYNOPSIS...A STRONG TROUGH OF LOW PRESSURE WILL TRACK THROUGH THE GREAT BASIN THIS WEEKEND...BRINGING COOLER AFTERNOON TEMPERATURES... GUSTY WINDS AND A CHANCE OF SHOWERS SATURDAY INTO SUNDAY. HIGH PRESSURE WILL START TO BUILD OVER THE AREA MONDAY AND REMAIN THROUGH THE UPCOMING WEEK FOR DRY CONDITIONS AND WARMING TREND. && .DISCUSSION...DEEP UPPER TROUGH ALONG THE WEST COAST EARLY THIS AFTERNOON WITH UPPER LOW NEAR THE WASHINGTON COAST CENTERED VICINITY 46N/130W. FAIRLY THICK CLOUD COVER OVER MUCH OF SE AZ AT THIS TIME ALONG WITH SOME GUSTY SWLY/WLY WINDS ACROSS SANTA CRUZ AND COCHISE COUNTIES. MOSTLY CLOUDY SKIES WITH PRECIP-FREE CONDITIONS MOST SECTIONS TONIGHT ALTHOUGH WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS ACROSS THE WHITE MOUNTAINS. SWLY FLOW TO INCREASE AT ALL LEVELS ACROSS THIS FORECAST AREA SAT AS TROUGH CONTINUES TO DEEPEN OVER THE INTERMOUNTAIN WEST. BELIEVE MAIN IMPACT FROM THIS SYSTEM SAT WILL BE INCREASED SURFACE WINDS...WITH BREEZY TO WINDY CRITERIA EXPECTED TO BE ACHIEVED SAT AFTERNOON. INCREASED MOISTURE SHOULD BE SUFFICIENT TO JUSTIFY AT LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS AREAWIDE BY SAT AFTERNOON. AT THIS TIME APPEARS THE BEST CHANCE OF MEASURABLE PRECIP WILL BE SAT NIGHT INTO SUN. AS NOTED IN THE MORNING DISCUSSION...03/12Z GFS/ECMWF HAVE TRENDED MORE PROGRESSIVE WITH THE WRN CONUS TROUGH THAN GFS/ECMWF SOLUTIONS FROM 2 DAYS AGO. THUS...APPEARS PRECIP WILL END SOONER THAN DEPICTED WITH THE THUR FORECAST PACKAGE ISSUANCE. DRY CONDITIONS EXPECTED TO RETURN AREAWIDE MON AS NWLY FLOW TO PREVAIL. RIDGE TO BUILD OVER THE AREA TUE-WED THEN FLATTEN SOMEWHAT NEXT THUR AS TROUGH STARTS TO DEEPEN ALONG THE WEST COAST. NEAR-NORMAL DAYTIME HIGH TEMPS SAT FOLLOWED BY ABOUT 10 DEGS OR SO OF COOLING SUN. WARMING TREND STARTING MON AND CONTINUING INTO THE MIDDLE OF THE UPCOMING WEEK. && .AVIATION...MOSTLY CLOUDY SKIES TONIGHT WITH CLOUD BASES MAINLY AT OR ABOVE 10K FT AGL" onClick="return popup(this, 'notes')">AGL. CLOUDS MAINLY BKN-OVC SATURDAY AHEAD OF A STRONG LOW PRESSURE SYSTEM APPROACHING FROM THE NORTHWEST. SLIGHT CHANCE OF TSRA/SHRA ACROSS ALL OF SE AZ ESPECIALLY AFTER 18Z SATURDAY. SCT SHRA SATURDAY NIGHT INTO SUNDAY. SURFACE WINDS SELY/ SLY 5-15 KTS TONIGHT...BECOMING SWLY 10-25 KTS WITH A FEW GUSTS TO 35 KTS DURING THE 18Z-23Z PERIOD SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. $$ BF WEATHER.GOV/TUCSON