Expires:No;;644837 FXUS65 KVEF 141819 AAA AFDVEF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 1018 AM PST TUE FEB 14 2012 .SYNOPSIS...A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS ARIZONA TODAY WITH CONDITIONS IMPROVING FROM WEST TO EAST THIS AFTERNOON AND EVENING. A SECOND STORM WILL THEN BRING ANOTHER ROUND OF STRONG WINDS...INCREASED CLOUD COVER AND A CHANCE FOR RAIN AND SNOW ON WEDNESDAY. && .UPDATE...ALLOWED WINTER WEATHER PRODUCTS FOR SOUTHERN NEVADA TO EXPIRE AT THE TOP OF THE HOUR...CANCELLED WINTER WEATHER ADVISORY FOR NORTHERN MOHAVE COUNTY. CAN NOT RULE OUT A FEW LIGHT FLURRIES LINGERING OVER OVER THE MOUNTAINS OF MOHAVE...LINCOLN AND CLARK COUNTIES. OTHERWISE LOOK FOR IMPROVING CONDITIONS/LESS CLOUD COVER THIS AFTERNOON AND TONIGHT UNDER WEAK RIDGE. NEXT LOW OFF THE NORTHWEST COAST WILL SINK SOUTH DOWN THE SOUTHERN SIERRA SPINE WEDNESDAY AFTERNOON AND CONTINUE SOUTH INTO NORTHWEST MEXICO THURSDAY. WILL TACKLE THIS SYSTEM MORE DURING THE AFTERNOON DISCUSSION. && .AVIATION...MCCARRAN...THE CLOUD COVER...ESPECIALLY THE LOWER LEVEL CLOUDS...WILL CONTINUE TO DECREASE IN COVERAGE THIS MORNING. CEILINGS SHOULD BE ABOVE 5000 BY NOON AT THE LATEST. THE REST OF THE DAY LOOKS TRANQUIL WITH LIGHT WINDS. ANOTHER STORM SYSTEM WILL MOVE INTO THE AREA WEDNESDAY AFTERNOON AND BRING ANOTHER ROUND OF RAIN AND CEILINGS BELOW 5000 FEET. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...UPPER LOW WILL CONTINUE MOVING OUT OF SRN NEVADA AND ACROSS ARIZONA TODAY...WITH SCATTERED PRECIPITATION AND HIGHER TERRAIN OBSCURED. ANOTHER STORM SYSTEM WILL MOVE INTO THE AREA WEDNESDAY AFTERNOON AND BRING ANOTHER ROUND OF RAIN AND CEILINGS BELOW 5000 FEET. && .PREV DISCUSSION... 319 AM PST TUE FEB 14 2012 .SHORT TERM...IR/WV SATELLITE IMAGERY SHOWS THE UPPER LOW LOCATED NEAR THE NV/AZ/UT BORDER THIS MORNING WITH PLENTY OF WRAPAROUND MOISTURE MOVING AROUND THE BACKSIDE INTO LINCOLN...CENTRAL AND SOUTHERN NYE...INYO AND CLARK COUNTIES. IR ENHANCEMENT SUGGESTS THERE IS SCATTERED RAIN AND SNOW SHOWERS IN THESE AREAS BUT PRECIPITATION AMOUNTS ARE THOUGHT TO BE GENERALLY LIGHT BASED ON REPORTED ONE HOUR AMOUNTS. THE LOW IS FORECAST TO MIGRATE SLOWLY TO THE SOUTHEAST AND WEAKEN WITH THE TROUGH AXIS CUTTING THROUGH EASTERN ARIZONA BY 4 PM. SHOWERS WILL END AND SKY CONDITIONS WILL IMPROVE IN THE WEST TODAY AND THE REST OF THE AREA LATER TODAY AS A BRIEF PERIOD OF SHORTWAVE RIDGING SLIDES SOUTH INTO THE AREA. WINDS WILL BEGIN TO WEAKEN THROUGH THE DAY BECOMING GENERALLY LIGHT ACROSS THE CENTRAL AND SOUTHERN CWA WITH NORTH WINDS 10-20 MPH ACROSS THE NORTHERN ZONES. TEMPERATURES WILL TOP OUT ABOUT 5-7 DEGREES BELOW NORMAL TODAY UNDER MOSTLY CLOUDY CONDITIONS. THE NEXT POTENT SYSTEM IS APPROACHING THE AREA TUESDAY NIGHT AND THE MODEL FORECASTED LOCATION OF THE H5 LOW CENTER IS ANYWHERE FROM RENO NORTH TO THE OR/NV/CA BORDER. THE ECMWF IS THE FASTEST SOLUTION IN BRINGING THE LOW THROUGH THE WESTERN HALF OF THE CWA WITH OTHER MODELS LAGGING BY A FEW HOURS. THE LOCAL 4KM ARW FORECASTS ANOTHER ROUND OF STRONG WINDS FIRST IN THE SIERRA WEDNESDAY MORNING THEN ACROSS THE DESERTS IN THE AFTERNOON. ALSO...STRONG NORTH WINDS ARE FORECAST BEHIND THE SYSTEM GENERALLY IMPACTING INYO...ESMERALDA AND NYE COUNTIES. PRECIPITATION COULD BE INITIALLY INTENSE WITH THIS SYSTEM BUT RELATIVELY SHORT LIVED DUE TO THE SPEED AT WHICH THE SYSTEM MOVES THROUGH THE REGION. SNOW LEVELS REMAIN NEARLY STEADY AT 3000-4000 FEET THROUGH THE LIFE OF THE SYSTEM. IN ORDER TO AVOID CONFUSION WITH THE SYSTEM THAT IS CURRENTLY IMPACTING THE AREA...DECIDED TO WAIT ON ISSUING ANY WATCH/WARNING/ADVISORY PRODUCTS FOR THE WEDNESDAY SYSTEM WITH THIS FORECAST PACKAGE. TEMPERATURES COULD WARM A COUPLE OF DEGREES ON TUESDAY BUT WEDNESDAY HIGHS WILL BE A TOUGH CALL DUE TO THE INCREASED CLOUD COVER ASSOCIATED WITH THE NEXT SYSTEM AND THE GENERALLY SOUTHERN FLOW INTO THE EASTERN AND SOUTHERN REGIONS OF THE AREA. CURRENT THINKING IS THAT IT WILL BE COLDER IN THE WEST WITH LITTLE CHANGE OVER THE EASTERN HALF OF THE CWA. CONDITIONS ARE FORECAST TO IMPROVE RAPIDLY ON THURSDAY WITH TEMPERATURES WARMING BACK TO NEAR NORMAL. .LONG TERM...FRIDAY THROUGH EARLY NEXT WEEK...DRY CONDITIONS AND NEAR NORMAL TEMPERATURES ARE EXPECTED ON FRIDAY WITH SHORTWAVE RIDGING ACROSS THE REGION. THE NEXT SYSTEM IS PROGGED TO BRUSH PAST NORTHERN ZONES LATE SATURDAY THROUGH SUNDAY MORNING WHICH WILL DECREASE TEMPERATURES BACK TO AROUND 5 DEGREES BELOW NORMAL ON AVERAGE AND BRING ANOTHER SLIGHT CHANCE OF PRECIPITATION TO THE SOUTHERN GREAT BASIN. NORTHERLY WINDS WILL INCREASE BEHIND THIS FEATURE ON SUNDAY WITH STRONGEST VALUES EXPECTED DOWN ALONG THE COLORADO RIVER VALLEY ZONES. MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS WEEKEND FEATURE. WHILE ALL MODELS KEEP THE AREA UNDER NORTHWESTERLY FLOW THROUGH THE FIRST HALF OF NEXT WEEK...THERE ARE LARGE DIFFERENCES IN TIMING ANY SHORTWAVES WITHIN THE FLOW...SO HAVE THE FAR EXTENDED MOSTLY UNCHANGED...JUST REMOVING MENTION OF PRECIP FROM THE FORECAST TUESDAY AND BEYOND AS THE OVERALL CONSENSUS IS THAT THE ERN PAC RIDGE WILL TRANSITION SLIGHTLY EASTWARD AND KEEP ANY ADDITIONAL SHORTWAVES DROPPING SOUTH IN THE FLOW FAR ENOUGH EAST OF THE REGION TO HAVE ANY MAJOR IMPACTS. && .AVIATION...MCCARRAN...ANOTHER ROUND OF PRECIP WILL BE POSSIBLE THROUGH 14Z THIS MORNING AS THE CENTER OF A LOW PRESSURE SYSTEM PASSES OVER THE AREA. CIGS WILL REMAIN AROUND 5-6KFT AGL DURING THIS TIME..AND POTENTIALLY DOWN TO 4KFT DURING ANY PRECIP. CONDITIONS WILL BEGIN TO IMPROVE BY MID MORNING WITH THE LOW TO THE EAST AND RIDGING BEGINS TO BRIEFLY BUILD BACK IN. CLOUD COVERAGE SHOULD THIN OUT/RISE ENOUGH TO ALLOW VFR BY 17Z THIS MORNING. THE NEXT ROUND OF WEATHER IS EXPECTED LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...UPPER LOW WILL CONTINUE MOVING OUT OF SRN NEVADA AND ACROSS ARIZONA TODAY...WITH SCATTERED PRECIPITATION AND HIGHER TERRAIN OBSCURED. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...NONE. AZ...NONE. CA...NONE. && $$ UPDATE...PIERCE/JACQUES PREV DISCUSSION...SALMEN/KENNEDY HTTP://WEATHER.GOV/LASVEGAS