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993 FXUS65 KVEF 032309 AFDVEF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 309 PM PST SUN MAR 3 2013 .SYNOPSIS...A LOW PRESSURE SYSTEM MOVING FROM CENTRAL CALIFORNIA ACROSS SOUTHERN NEVADA TONIGHT WILL PRODUCE SCATTERED TO NUMEROUS SHOWERS ACROSS CENTRAL AND SOUTHEAST NEVADA TROUGH EARLY MONDAY MORNING. MILD CONDITIONS MONDAY AND TUESDAY WILL BE FOLLOWED BY A STRONGER STORM BRINGING WINDY...COOLER AND SHOWERY WEATHER TO MUCH OF THE REGION THE SECOND HALF OF THE WEEK. && .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...SOUTHWEST WINDS WERE RESPONDING ABOUT AS EXPECTED AHEAD OF THE INCOMING UPPER LOW MOVING ACROSS CENTRAL CALIFORNIA. THE STRONGEST GUSTS WERE OCCURRING ACROSS NORTHWEST SAN BERNARDINO COUNTY AND IN RED ROCK CANYON. THE LATEST HIGH RES MODEL CROSS SECTIONS INDICATE GUSTS OVER 40 MPH SHOULD CONTINUE IN RED ROCK CANYON UNTIL ABOUT 9-10 PM PST AND THE ADVISORY WAS EXTENDED ACCORDINGLY. THOUGH GUSTS OVER 40 MPH HAVE YET TO MATERIALIZE AT BARSTOW-DAGGETT AND TWENTYNINE PALMS...THE BELT OF WINDS WILL SHIFT SOUTHWARD AHEAD OF THE UPPER LOW AND ASSOCIATED SURFACE FRONT SLIDING ACROSS SOUTHERN NEVADA AND SURROUNDING AREAS TONIGHT. SHOWERS LOOK LIKELY ACROSS LINCOLN COUNTY OVERNIGHT AS THE MOISTURE BAND BECOMES FAIRLY CONCENTRATED OVER EAST CENTRAL NEVADA AND POP VALUES WERE INCREASED TO ACCOUNT FOR THIS. NORTH BREEZES WILL DEVELOP ACROSS MUCH OF THE REGION MONDAY AS THE SYSTEM QUICKLY PULLS AWAY TO THE EAST. HIGH TEMPS WILL ALSO DROP SEVERAL DEGREES. A RIDGE QUICKLY TRAVERSES THE REGION MONDAY AND MONDAY NIGHT THEN SOUTHWEST FLOW INCREASES TUESDAY AND ESPECIALLY WEDNESDAY AS A MUCH BROADER AND STRONGER PACIFIC LOW MOVES INTO THE WEST COAST. THIS WILL LEAD TO ANOTHER ROUND OF GUSTY SOUTHWEST WINDS ACROSS THE REGION WEDNESDAY AND SOME POTENTIAL FOR A STRONG DOWNSLOPE EVENT FOR THE EAST SLOPES OF THE SOUTHERN SIERRA/OWENS VALLEY. WIND WILL BE THE MAIN INITIAL CONCERN. MOISTURE ON THE SOUTHEAST PERIPHERY OF THE SYSTEM WILL BE LIMITED INITIALLY BUT KEPT A CHANCE OF PRECIP OVER NORTHERN INYO...ESMERALDA AND CENTRAL NYE COUNTIES WEDNESDAY EVENING. LITTLE VARIATION IN TEMPERATURES IS EXPECTED TUESDAY AND WEDNESDAY. .LONG TERM...THURSDAY THROUGH SUNDAY...MEDIUM RANGE MODEL AGREEMENT APPEARS TO HAVE DETERIORATED SLIGHTLY WITH THE LATEST 12Z GUIDANCE. FEW CHANGES WERE MADE TO THE INHERITED FORECAST AND GENERALLY BROAD-BRUSHED GRIDS STILL IN PLACE. A LONGWAVE TROUGH WILL BE DIGGING SOUTH ALONG THE WEST COAST THURSDAY. SOUTH-SOUTHWEST FLOW ACROSS THE AREA WILL BRING BREEZY CONDITIONS TO MUCH OF THE AREA AS WELL AS INCREASE MID-HIGH CLOUDS. AT THIS TIME WINDS THURSDAY LOOK TO BE AT OR JUST BELOW LEVELS SEEN WEDNESDAY...AND NOT QUITE AS WIDESPREAD. THIS WOULD GIVE US WINDS BELOW WIND ADVISORY LEVELS IN MOST LOCATIONS...THOUGH THERE IS THE POTENTIAL FOR ADVISORY LEVEL WINDS...MAINLY ACROSS WESTERN SAN BERNARDINO COUNTY AND THE SPRING MOUNTAINS. PRECIPITATION IS EXPECTED TO DEVELOP ACROSS THE NORTHERN HALF OF THE FORECAST AREA THROUGH THURSDAY/THURSDAY NIGHT...THEN TRANSITION TO THE EASTERN HALF OF THE AREA FRIDAY AND SATURDAY...THEN TAPERING OFF FROM WEST TO EAST. SNOW LEVELS MAY BRIEFLY DROP TO AS LOW AS 3000-4000K FEET AS THE UPPER LEVEL LOW PASSES OVER/NEAR THE FORECAST AREA FRIDAY NIGHT. OTHERWISE...SNOW LEVELS ARE EXPECTED TO REMAIN ABOVE 4000-4500 FEET DURING THE EVENT...WITH ACCUMULATING SNOWFALL POSSIBLE ABOVE 4500 FEET. PINPOINTING PRECIP AMOUNTS REMAINS DIFFICULT...BUT AREAS THAT HAVE THE BEST CHANCES OF RECEIVING PRECIP WILL LIKELY SEE 0.10-0.40 INCHES OF LIQUID...WITH LOCALLY HIGHER AMOUNTS...ESPECIALLY IN HIGHER TERRAIN OR WITH HEAVIER SHOWERS. THESE AMOUNTS HAVE DECREASED COMPARED TO MODEL QPF AMOUNTS THAT WERE ADVERTISED 24 HOURS AGO. MODELS DO INDICATE THE POTENTIAL FOR WEAK CONVECTION WITH AREAS OF NEAR ZERO OR NEGATIVE LI`S...PRIMARILY AS THE TROUGH/LOW MOVE OVER THE FORECAST AREA FRIDAY/FRIDAY NIGHT. AS THE SURFACE LOW PUSHES TO THE EAST/SOUTHEAST FRIDAY NIGHT INTO SATURDAY MORNING MODELS ARE PRODUCING A DECENT PRESSURE GRADIENT ACROSS THE REGION WITH STIFF NORTH WINDS ACROSS MUCH OF THE FORECAST AREA. THESE WINDS ALSO APPEAR TO NEARING ADVISORY LEVELS. TEMPERATURES WILL DROP BELOW NORMAL THURSDAY THROUGH SATURDAY AND LOOK TO BE ROUGHLY 15 DEGREES COOLER THAN THIS AFTERNOON. CONDITIONS WILL GRADUALLY BEGIN TO IMPROVE SUNDAY AS HIGHER PRESSURE BUILDS INTO THE REGION...THOUGH BREEZY CONDITIONS WILL BE POSSIBLE DOWN THE COLORADO RIVER VALLEY. && .AVIATION...FOR MCCARRAN...WINDS GUSTING TO 25-35 KTS WILL CONTINUE INTO THIS EVENING...WITH OCCASIONAL BLOWING DUST AT OR NEAR THE TERMINAL. SPEEDS WILL BEGIN TO SLOWLY DECREASE AFTER 02Z. BKN CLOUDS BASES ARE GENERALLY EXPECTED FROM 10-12K FEET WITH SCATTERED LOWER CLOUDS BETWEEN 6-10K FEET AT TIMES. WINDS ARE EXPECTED TO DECREASE AROUND MIDNIGHT AND WILL BEGIN TO TURN TO THE NORTHEAST AS A SYSTEM MOVES THROUGH THE REGION. CLEARING SKIES AND LIGHTER WINDS FAVORING A NORTH/NORTHEAST DIRECTION ARE EXPECTED MONDAY. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...GUSTY SOUTH TO SOUTHWEST WINDS WILL CONTINUE INTO THIS EVENING. THE STRONGEST WINDS WILL BE ACROSS WESTERN SAN BERNARDINO COUNTY...WHERE GUSTS TO AROUND 40 KTS WILL BE POSSIBLE. CLOUDS ARE EXPECTED TO LOWER...PRIMARILY IN THE NORTH...TO 5-10K FEET...WITH POSSIBLE SHOWERS. WINDS SPEEDS WILL DECREASE ACROSS THE REGION OVERNIGHT...BEGINNING TO FAVOR A NORTHERLY DIRECTION MONDAY. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR NVZ019. AZ...NONE. CA...WIND ADVISORY UNTIL 4 AM PST MONDAY FOR CAZ523-525. && $$ ADAIR/WOLCOTT HTTP://WEATHER.GOV/LASVEGAS
