801  
FXUS65 KREV 081047  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
247 AM PST THU DEC 8 2022  
   
..POTENT WINTER STORM FRIDAY NIGHT THROUGH SUNDAY
 
 
   
SYNOPSIS
 
 
A FAST-MOVING STORM WILL BRING A QUICK FEW INCHES OF SNOW AND GUSTY  
WINDS TO THE SIERRA TONIGHT INTO FRIDAY MORNING. A STRONG SIERRA  
STORM ARRIVES FRIDAY NIGHT, WITH HIGH CONFIDENCE IN HEAVY  
SNOWFALL AND SIGNIFICANT TRAVEL IMPACTS TO THE SIERRA THROUGH THE  
WEEKEND. CHANCES FOR ACCUMULATING SNOW INTO WESTERN NEVADA VALLEYS  
IS POSSIBLE SATURDAY NIGHT INTO SUNDAY.  
 

 
   
SHORT TERM...THROUGH FRIDAY NIGHT
 
 
FAST MOVING TROUGH WILL SWING THROUGH THE REGION TONIGHT AND THEN  
EXIT TO THE EAST FRIDAY AS A MORE ROBUST SYSTEM DROPS DOWN THE WEST  
COAST FRIDAY NIGHT. THE OVERALL IMPRESSION OF THIS LEAD SHORTWAVE  
HAS NOT CHANGED WITH ONLY LIGHT QPF/SNOW AMOUNTS AND PLENTY OF WIND.  
HIGH CLOUDS WILL INCREASE TODAY WITH SOUTHERLY WINDS BEGINNING TO  
INCREASE OVER THE RIDGES AND ACROSS FAR NORTHEAST CA/NORTHWEST NV.  
TODAY WILL GENERALLY BE A COOL BUT TRANQUIL DAY FOR MOST VALLEY  
LOCATIONS. WINDS INCREASE SUBSTANTIALLY TONIGHT WITH 700MB FLOW  
AROUND 50 KTS WHICH WILL PUT GUSTS ACROSS THE SIERRA RIDGES 80+ MPH.  
GUSTY SOUTH TO SOUTHWEST WINDS WILL PEAK OVERNIGHT AS WELL AS  
PRECIPITATION ARRIVES AND BANKS ON THE WEST SLOPES. THERE IS NOT  
GOING TO BE A LOT OF SPILLOVER, SO A RATHER WINDY NIGHT IS IN STORE  
WITH GUSTS 25-35 MPH, LOCALLY TO 50+ MPH IN WINDPRONE AREAS ALONG  
HWY 395. FORTUNATELY, THE FRONT WILL PASS LATE TONIGHT/DAYBREAK AND  
WINDS WILL ABATE SOME FOR FRIDAY WITH MORE TYPICAL BREEZES.  
 
WPC QPF GUIDANCE DID NOT CHANGE MUCH, SHOWING 0.25-0.50" ALONG THE  
CREST, TAPERING QUICKLY TO THE LEE OF THE SIERRA. AN INCH OR TWO MAY  
FALL IN THE TAHOE BASIN AND SURPRISE VALLEY WHILE 2-6" CAN BE  
EXPECTED ALONG THE CREST. ONLY VERY LIGHT AND SPOTTY ACCUMULATIONS  
ARE EXPECTED IN ISOLATED-SCATTERED SNOW SHOWERS ACCOMPANYING THE  
FRONT ACROSS WESTERN NV/HWY 395 CORRIDOR THROUGH MONO COUNTY LATE  
TONIGHT.  
 
WINDS BEGIN TO INCREASE AGAIN FRIDAY NIGHT AS THE NEXT MORE  
ORGANIZED WINTER STORM DROPS SOUTHWARD ALONG THE WEST COAST. BREEZY  
TO WINDY CONDITIONS WILL DEVELOP AREAWIDE OVERNIGHT WITH THE INITIAL  
BOUT OF SNOW ARRIVING IN THE NORTHERN SIERRA/NORTHEAST CA OVERNIGHT.  
CONDITIONS WILL BEGIN TO DETERIORATE ACROSS TRANS-SIERRA ROUTES  
AFTER MIDNIGHT FRIDAY NIGHT, ESPECIALLY FROM EBBETTS PASS NORTHWARD,  
WITH SNOW BECOMING HEAVY BY DAYBREAK. HOHMANN  
   
LONG TERM...SATURDAY THROUGH NEXT WEEK
 
 
 
CLASSIC SIERRA WINTER STORM WILL BRING SIGNIFICANT IMPACTS TO  
TRAVEL THROUGH THE MOUNTAINS THIS WEEKEND. A STRONG AREA OF LOW  
PRESSURE DROPPING OUT OF THE GULF OF ALASKA WILL ENTRAIN  
SUBTROPICAL MOISTURE ALONG AN IDEAL SOUTHWESTERLY POLAR JET STREAM.  
THE MAIN LIMITING FACTOR TO THE STORM IS THE OVERALL SPEED AS THE  
PROGRESSIVE FLOW PUSHES THE STORM RELATIVELY QUICKLY THROUGH THE  
REGION. MAIN CHANGES OVERNIGHT WERE A DECREASE IN THE QPF GUIDANCE  
WITH THE SHORTER RESIDENCE TIME.  
 
HEAVY SNOW WILL MOVE QUICKLY INTO THE SIERRA AND NE CALIFORNIA  
SATURDAY MORNING WITH THE MOST INTENSE SNOWFALL SATURDAY THROUGH  
SATURDAY NIGHT AS SUBTROPICAL MOISTURE IS DRAWN INTO THE SIERRA.  
SNOW LEVELS WILL RISE TO BETWEEN 5000-6000 FEET DURING THIS TIME  
PERIOD WITH SNOWFALL RATES OF OF 1-2"/HR FOR 18-24 HRS. INTENSE  
SNOWFALL RATES WILL CREATE PERIODS LOW VISIBILITY AND VERY  
DIFFICULT TRAVEL SATURDAY THROUGH SATURDAY NIGHT. WITH THE WARMER  
SUBTROPICAL INFLUENCE DURING THIS TIME PERIOD SNOW TO LIQUID  
RATIOS WILL FALL TO AROUND 8/1.  
 
THE COLDER PART OF THE STORM MOVES INTO THE REGION SATURDAY NIGHT  
INTO SUNDAY WITH SNOW LEVELS DROPPING TO WESTERN NEVADA VALLEYS  
AS SNOW RATIOS RISE TO AROUND 12/1 OR MORE IN THE MOUNTAINS.  
CHANCES FOR ACCUMULATING SNOW IN THE VALLEYS CONTINUES TO LOOK  
BETTER WITH ~50-60% CHANCE OF 2+ INCHES INTO RENO/CARSON CITY AND  
INCREASING CHANCES OF 4+ INCHES IN SURROUNDING AREAS.  
 
STRONG WINDS SHOULD BE EXPECTED WITH THIS SYSTEM AS 700MB SPEEDS  
RISE TO 50-60KTS. WINDS IN EXCESS OF 100 MPH SHOULD BE EXPECTED  
FRIDAY NIGHT INTO SATURDAY WITH SURFACE WINDS OF 40-50 MPH  
POSSIBLE IN WESTERN NEVADA DURING THE DAY ON SATURDAY AS  
PRECIPITATION REMAINS MAINLY CONFINED TO THE MOUNTAINS.  
 
BY SUNDAY THE MAIN COLD FRONT WILL ALREADY HAVE MOVED THROUGH THE  
REGION WITH COLD AIR, LIGHTER WINDS, AND LINGERING SNOW SHOWERS IN  
PLACE. SNOW ACCUMULATIONS WILL QUICKLY TAPER DURING THE DAY ON  
SUNDAY, BUT TRAVEL OVER SIERRA PASSES COULD REMAIN QUITE  
CHALLENGING.  
 
TEMPERATURES FOR MUCH OF NEXT WEEK WILL BE 10+ DEGREES BELOW  
NORMAL WITH HIGHS ONLY REACHING THE LOW TO MID 30S IN LOWER  
VALLEYS AND LOWS DIPPING INTO THE TEENS AND SINGLE DIGITS. SOME OF  
THE COLDER VALLEYS COULD DROP EASILY BELOW ZERO MONDAY-TUESDAY  
NIGHTS IF CLOUD COVER CLEARS SUFFICIENTLY.  
 
STORM ACTIVITY REMAINS IN THE CARDS BY THE MIDDLE TO END OF NEXT  
WEEK AS ANOTHER TROUGH IS EXPECTED TO DEEPEN ALONG THE WEST COAST.  
HOW MUCH MOISTURE MOVES INTO THE REGION REMAINS UNCERTAIN AS  
MODELS CONTINUE TO STRUGGLE WITH THE PLACEMENT OF THE DEVELOPING  
TROUGH. -ZACH  
 

 
   
AVIATION
 
 
* PATCHY FREEZING FOG WILL PERSIST IN THE SIERRA VALLEYS THIS  
MORNING ALTHOUGH THE COVERAGE HAD DECREASED OVER THE PAST COUPLE  
OF HOURS. THE FREEZING FOG AROUND KTRK IS VERY SHALLOW AND MAY  
COME AND GO VICINITY OF THE RUNWAY THROUGH 17Z. OTHERWISE VFR WITH  
BREEZY WINDS ACROSS THE RIDGES TODAY.  
 
* A FAST MOVING STORM WILL BRING A PERIOD OF LIGHT SNOW SHOWERS TO  
THE SIERRA AND NORTHEAST CA TONIGHT WITH ACCUMULATIONS UP TO 2  
INCHES POSSIBLE ON THE RUNWAYS AT KTRK-KTVL. WIDESPREAD MVFR  
(PERIODIC IFR) CONDITIONS AND TERRAIN OBSCUREMENT WILL BE POSSIBLE  
FOR THE TAHOE AREA AIRPORTS LATE THIS EVENING AND OVERNIGHT. A FEW  
LIGHT SNOW SHOWERS MAY MAKE IT TO THE OTHER AIRPORTS AS THE FRONT  
MOVES EAST, BUT ACCUMULATIONS WILL BE VERY LIGHT, A DUSTING IN  
MOST CASES.  
 
* THE BIGGEST THREAT FROM THIS STORM WILL BE WIND AS FL100 WINDS  
INCREASE TO AROUND 50 KTS. MODERATE TURBULENCE IS A GOOD BET THIS  
EVENING INTO DAYBREAK FRIDAY ALONG WITH LLWS. S-SW SURFACE WINDS  
WILL GUST 20-25 KTS, LOCALLY MUCH STRONGER IN THE EASTERN SIERRA  
FROM KMEV-KMMH OVERNIGHT INTO EARLY FRIDAY MORNING. WINDS WILL  
DECREASE WITH IMPROVING CONDITIONS FRIDAY MORNING AS THE FRONT AND  
TROUGH EXIT TO THE EAST.  
 
* A MUCH STRONGER AND PROLONGED WINTER STORM ARRIVES FRIDAY NIGHT  
AND PERSISTS THROUGH THE WEEKEND. ACCUMULATING SNOW AND WIND WILL  
BRING A MYRIAD OF IMPACTS TO AVIATION.  
 
HOHMANN  
 

 
   
REV WATCHES/WARNINGS/ADVISORIES
 
 
NV...WINTER STORM WATCH FROM FRIDAY EVENING THROUGH LATE SUNDAY NIGHT  
NVZ002.  
 
CA...WINTER STORM WATCH FROM FRIDAY EVENING THROUGH LATE SUNDAY NIGHT  
CAZ071.  
 
WINTER STORM WATCH FROM FRIDAY EVENING THROUGH LATE SUNDAY NIGHT  
CAZ072.  
 
WINTER STORM WATCH FROM FRIDAY EVENING THROUGH LATE SUNDAY NIGHT  
CAZ073.  
 

 
 

 
 
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