000 FXUS65 KREV 041343 CCA AFDREV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RENO NV 337 AM PST TUE NOV 4 2008 .SHORT TERM... SHEARED UPPER LOW QUICKLY MOVING THROUGH THE WEST COAST WITH A FAST MOVING SRN BRANCH OVER NEVADA AND THE SLOWER MAIN LOW OVER THE PACNW. PRECIP BANDS HAVE BEEN STEADY OVER THE TAHOE AND RENO AREAS OVERNIGHT AND ARE SLOWLY TAPERING OFF THIS MORNING. WILL CANCEL THE SNOW ADVISORIES WITH THE MORNING PACKAGE AS FORCING CONTINUES TO WEAKEN. ANOTHER BIG STORY WITH THIS LOW HAS BEEN THE WINDS WITH MANY LOCATIONS REMAINING QUITE WINDY OVERNIGHT AS THE COLD FRONT PASSED. HIGH RES MODIS WATER VAPOR IMAGERY SHOWS GOOD MOUNTAIN WAVE ACTIVITY ALONG THE SIERRA AS THE SUPPRESSED TROPOPAUSE MOVED THROUGH OVERNIGHT. THIS UPPER FEATURE LIKELY HELPED TO DUCT STRONGER WINDS ALOFT DOWN TO THE SURFACE IN THE STABLE PRE-FRONTAL ENVIRONMENT SOUTH OF THE RENO AND TAHOE AREAS. SEE THE LOCAL STORM REPORT REGARDING OVERNIGHT WINDS AND PRELIMINARY PRECIP AMOUNTS. POST-FRONTAL WINDS TODAY WILL NOT BE AS STRONG AS THEY WERE OVERNIGHT HOWEVER BREEZY CONDITIONS ON PYRAMID AND TAHOE WILL WARRANT LAKE WIND ADVISORIES. UPPER LEVEL RIDGING OVER THE ERN PACIFIC THIS MORNING WILL SLOWLY PUSH THE CYCLONIC FLOW EAST OF THE REGION BRINGING A MORE STABLE ATMOSPHERE AND DIMINISHING THE THREAT OF SHOWERS. MAINLY CLEAR SKIES TONIGHT WILL ALLOW FOR GOOD RADIATIONAL COOLING AND LIKELY FOG FORMATION IN THE FAVORABLE SIERRA VALLEYS. STRONG WARM AIR ADVECTION ASSOCIATED WITH THE UPPER RIDGING OCCURS OVER THE REGION WEDNESDAY. DECENT MID AND UPPER LEVEL MOISTURE ACCOMPANIES THE WAA AND COULD BE SUFFICIENT TO CREATE LIGHT RAIN OR SNOW OVER THE FAR NRN ZONES WED AND WED NIGHT. HIGHER ELEVATIONS WILL SEE RISING TEMPERATURES AS EARLY AS WED...HOWEVER VALLEY LOCATIONS WILL NOT SEE A SIGNIFICANT TEMPERATURE REBOUND UNTIL THURSDAY WHEN WARMER TEMPS ALOFT FINALLY MIX DOWN TO THE SURFACE. JORDAN .LONG TERM /FRIDAY THROUGH MONDAY/... ON FRIDAY MODELS AGREE THERE WILL BE A RIDGE OVER THE GREAT BASIN. BY SATURDAY THE RIDGE BREAKS DOWN AS A PROGRESSIVE PACIFIC FLOW DEVELOPS ACROSS THE PACIFIC. THIS WILL PUSH A FEW IMPULSES INTO THE WEST COAST FOR SUNDAY AND MONDAY. HOWEVER UNCERTAINTY REMAINS IN THE TRACK OF THE ENERGY. THE GFS HAS PUSHED THE STORM TRACK FARTHER NORTH...WITH A COUPLE PIECES OF ENERGY PASSING THROUGH THE PACIFIC NORTHWEST. THIS WOULD LIMIT THE CHANGE OF RAIN/SNOW TO LASSEN AND NORTHERN WASHOE...WITH BREEZY CONDITIONS FOR THE REST OF THE FORECAST AREA. THE ECMWF DEVELOPS A CUT OFF LOW OVER NEVADA ON SUNDAY...WHICH WOULD TURN THE AREA MUCH COLDER AND GIVE A BETTER CHANCE OF RAIN/SNOW. HAVE LEANED MORE TOWARDS THE GFS...AS IT HAS THE SUPPORT OF THE CANADIAN. LEFT CONDITIONS NEARLY THE SAME...WITH SLIGHT CHANCE TO CHANCE POPS...SATURDAY-MONDAY DUE TO TIMING ISSUES AND ZONAL FLOW. DID SHOW A COOLING TREND IN THE HIGHS...AS SUCCESSIVE DAYS OF CLOUDS WILL LIMIT HEATING. BRONG && .AVIATION... AREA OF LOW PRESSURE OVER EASTERN OREGON AND NORTHWEST NEVADA...WILL PUSH EAST TODAY. SNOW SHOWERS WILL CONTINUE OVER THE RENO-TAHOE AREA AS MOISTURE IS PUSHED UP THE WEST SLOPES WITH FAVORABLE WINDS AND INSTABILITY TO COUNTERACT SHADOWING FOR RENO-CARSON AREA. SHOWERS WILL TEMPORARILY REDUCE CONDITIONS TO MVFR...WITH IFR FOR THE HEAVIER SHOWERS IN THE SIERRA. WINDS HAVE PICKED UP IN MONO COUNTY...WITH RIDGE TOP GUSTS OF 80-85 KTS WITH DOWNSLOPE GUSTS IN THE MAMMOTH AREA OF 40-50KTS. THESE WINDS WILL SUBSIDE DURING THE NEXT FEW HOURS...BUT EXPECT 30-35KT DOWNSLOPE GUSTS TO CONTINUE FOR THE EAST SLOPES THROUGH THIS AFTERNOON. SIERRA WINDS AND MOUNTAIN WAVES MAY NOT SUBSIDE UNTIL TONIGHT. BRONG && .REV WATCHES/WARNINGS/ADVISORIES... NV...LAKE WIND ADVISORY UNTIL 6 PM PST THIS AFTERNOON FOR NVZ002-004. CA...LAKE WIND ADVISORY UNTIL 6 PM PST THIS AFTERNOON FOR CAZ072. && $$ HTTP://WEATHER.GOV/RENO ----------------------------------------------------------------------
