AREA FORECAST DISCUSSION

 
 FXUS65 KVEF 242214
 AFDVEF
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE LAS VEGAS NV
 213 PM PST TUE NOV 24 2009
 
 .SYNOPSIS...GUSTY NORTH WINDS DOWN THE COLORADO RIVER VALLEY WILL 
 CONTINUE THROUGH WEDNESDAY...WITH QUIET WEATHER OVER THE REMAINDER 
 OF THE AREA. TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL 
 WEDNESDAY AND THANKSGIVING DAY...THEN A COLD FRONT WILL BRING BREEZY 
 AND MUCH COOLER WEATHER OVER THE WEEKEND.
 &&
 
 .SHORT TERM...SATELLITE SHOWS THIN CIRRUS OVER MUCH OF OUR 
 CWFA...WITH A PATCH OF THICKER CIRRUS INVADING FROM THE NORTH. 
 SURFACE OBS SHOW LOCALLY GUSTY NORTH WINDS CONTINUING...ESPECIALLY 
 DOWN THE COLORADO RIVER. THIS WILL BE THE MAIN FORECAST PROBLEM FOR 
 THE SHORT TERM. PRESSURE GRADIENT BETWEEN KELY AND KEED IS STILL 
 11.9 MB AS OF 2 PM...COMPARED TO MODEL FORECASTS YESTERDAY OF ABOUT 
 9 MB. THE MODELS STILL SHOW GRADIENTS WEAKENING TOMORROW...BUT AM 
 SUSPICIOUS OF THAT TREND BASED ON WHAT HAPPENED TODAY. SUSPECT THE 
 MODELS MAY NOT BE HANDLING THE MAINTENANCE/STRENGTHENING OF SURFACE 
 HIGH PRESSURE IN THE GREAT BASIN BY THE VERY COLD NIGHTTIME 
 TEMPERATURES THERE. THUS...MANUALLY INCREASED WIND FORECASTS IN THE 
 BULLHEAD CITY AREA FOR TONIGHT AND TOMORROW. WINDS TODAY ARE RIGHT 
 ON THE BORDERLINE OF LAKE WIND ADVISORY CRITERIA FOR THE SECOND DAY 
 IN A ROW...BUT THE NATIONAL PARK SERVICE REPORTS NO PROBLEMS...SO 
 WILL AGAIN FORGO AN ADVISORY. CONDITIONS WILL PROBABLY BE BORDERLINE 
 AGAIN TOMORROW BEFORE THE WINDS FINALLY SUBSIDE A BIT ON 
 THANKSGIVING DAY. AS THE SHORT TERM COMES TO AN END THURSDAY 
 NIGHT...ATTENTION SHIFTS WEST TO A PACIFIC STORM APPROACHING THE 
 COAST. SENSIBLE WEATHER EFFECTS SHOULD BE MINIMAL THROUGH THURSDAY 
 NIGHT...WITH PRESSURE GRADIENTS BEGINNING TO REVERSE AS THE GREAT 
 BASIN HIGH GETS ERODED/KICKED TO THE EAST.
 
 .LONG TERM...AFTER SOME BETTER MODEL CONTINUITY DURING THE SECOND 
 HALF OF THE HOLIDAY WEEKEND...12Z SOLUTIONS DECIDED TO DIVERGE 
 AGAIN. MODELS ARE HAVING A DIFFICULT TIME WITH EXACT PLACEMENT AND 
 DEPTH OF TROUGH AS IT DIGS TO OUR EAST OVER THE FOUR CORNER STATES 
 THIS WEEKEND. NOT TO BORE EVERYONE WITH EXACT DETAILS LAST NIGHT 06Z 
 AND THE NEW 18Z DGEX ARE A GOOD COMPROMISE BETWEEN THE DEEPER ECMWF 
 AND THE WEAKER/MORE PROGRESSIVE GFS/GEM. AS TROUGH SLIDES ACROSS 
 FRIDAY NIGHT/SATURDAY THERE IS A SLIGHT CHANCE OF SHOWERS OVER THE 
 HIGHER TERRAIN OF SOUTHERN NEVADA AND NORTHWEST ARIZONA. ON THE 
 BACKSIDE OF THE TROUGH...NORTH WINDS WILL USHER IN COOLER 
 TEMPERATURES FOR THE WEEKEND. THE NORTH WIND WILL BE STRONGEST ON 
 SATURDAY AND SUNDAY WITH BREEZY CONDITIONS DOWN THE COLORADO RIVER 
 VALLEY. WINDS WILL DECREASE AND TEMPERATURES REBOUND EARLY NEXT WEEK 
 AS RIDGE BUILDS OVER THE SOUTHWEST STATES.
 &&
 
 .AVIATION...FOR MCCARRAN...FEW-SCT CIRRUS THROUGH WEDNESDAY. SURFACE 
 WINDS WILL REMAIN OUT OF THE NORTHEAST...AROUND 6-10KTS THROUGH 02Z. 
 LIGHT WEST TO NORTHWEST WIND OVERNIGHT. NORTHEAST WIND LESS THAN 10 
 KTS WILL DEVELOP AFT 17Z WEDNESDAY. 
 
 FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
 CALIFORNIA...NORTH TO NORTHEAST WINDS WILL CONTINUE INTO THE EARLY 
 EVENING THEN BECOME DOWNVALLEY LESS THAN 7 KTS THE REST OF TONIGHT. 
 NORTH WINDS OF 15-25KTS WILL AGAIN DEVELOP DOWN THE LOWER COLORADO 
 RIVER VALLEY AFT 16Z WEDNESDAY IMPACTING THE AREA BETWEEN KIFP AND 
 KEED. FEW-SCT CIRRUS THROUGH WEDNESDAY. 
 &&
 
 .VEF WATCHES/WARNINGS/ADVISORIES...
 NV...NONE.
 AZ...NONE.
 CA...NONE.
 &&
 
 

 
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