847  
FXUS65 KREV 272007  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
107 PM PDT WED OCT 27 2021  
   
SYNOPSIS
 
 
 
HIGH PRESSURE CONTINUES TO DOMINATE OUR WEATHER PATTERN THROUGH  
FRIDAY WITH VERY PLEASANT CONDITIONS. PATCHY FREEZING FOG IS  
POSSIBLE BY EARLY THURSDAY MORNING ACROSS PORTIONS OF THE COLDER  
SIERRA VALLEYS. OVERNIGHT FRIDAY INTO SATURDAY, A WEAK DISTURBANCE  
WILL BRING RAIN CHANCES TO AREAS NORTH OF INTERSTATE 80 WITH A  
SLIGHT CHANCE FOR A WINTRY MIX AT HIGHER ELEVATIONS. THE STORM  
TRACK WILL REMAIN FAVORABLE THROUGH THE FIRST PART OF NOVEMBER FOR  
A FEW ADDITIONAL ROUNDS OF PRECIPITATION.  
 
 

 
   
SHORT TERM (THROUGH FRIDAY NIGHT)
 
 
NO COMPLAINTS ABOUT THE WEATHER OVER THE NEXT DAY OR TWO AS  
RIDGING CONTINUES TO BUILD EASTWARD OVER THE GREAT BASIN WITH LESS  
CLOUD COVER EXPECTED THIS AFTERNOON COMPARED TO THIS TIME  
YESTERDAY. HIGHS TODAY WILL BE NEAR SEASONAL NORMALS - LOW/MID 60S  
IN THE LOWER VALLEYS AND WESTERN NEVADA, WITH MID TO UPPER 50S IN  
OUR ELEVATION CITIES. THE MAIN CONCERN IN THE NEXT 24 HOURS WILL  
BE THE POSSIBILITY FOR PATCHY FREEZING FOG ACROSS SOME OF THE FOG  
PRONE AREAS (SIERRA VALLEY, TRUCKEE, SOUTH LAKE TAHOE). LOWER  
CLOUD COVER THAN PREVIOUS DAYS, LIGHT WINDS, AND TEMP = DEWPOINT  
BY LATE OVERNIGHT INTO EARLY MORNING WILL BE THE DRIVING FACTORS  
BEHIND THE FOG THREAT. WITH TEMPERATURES BOTTOMING OUT IN THE 20S  
ACROSS THE AFOREMENTIONED VALLEYS, EXPECT THIS TO BE FREEZING FOG.  
MODEL FORECAST SOUNDINGS ALONG WITH MOS GUIDANCE SUGGESTS HIGH  
LEVEL CLOUDS WILL ROLL IN ACROSS THE AREA OVERNIGHT THU/FRI WHICH  
WILL LIMIT COOLING SO FOG FORMATION IS DOUBTFUL ON FRIDAY AND WILL  
LEAVE IT OUT OF THE FORECAST FOR NOW.  
 
SIMULATIONS CONTINUE TO SHOW A PROGRESSIVE SHORT WAVE TRAVERSING  
EASTWARD INTO NORTHERN CAL LATE FRIDAY NIGHT INTO EARLY SATURDAY.  
THE HIGHEST CHANCES FOR RAIN WILL BE NORTH OF I-80 WHERE THE  
GREATEST ENERGY ALONG WITH MOISTURE WILL BE. POPS WILL RANGE FROM  
10% NEAR I-80 TO 30% NEAR SURPRISE VALLEY IN EXTREME NE CA. DON'T  
EXPECT MUCH IN THE WAY OF RAINFALL DUE TO THE SHOWERY NATURE AND  
RATHER MEAGER (BUT NOT COMPLETELY UNFAVORABLE) CONDITIONS. THE  
WETTER SOLUTION HAS AT MOST 0.20 INCHES OVER A 12 HOUR PERIOD - SO  
NO MAJOR CONCERNS EXPECTED WITH THIS PRECIP. SNOW LEVELS BETWEEN  
8,000-9,000 FEET APPEAR TO PRECLUDE ANY SNOWFALL - EXCEPT PERHAPS  
SOME WINTRY MIX AT THE HIGHEST ELEVATIONS OF NE CALIFORNIA AND NW  
NEVADA.  
 
-DUSTIN  
 
   
LONG TERM (SATURDAY THROUGH NEXT WEDNESDAY)
 
 
LATE FRIDAY NIGHT INTO EARLY SATURDAY, ENSEMBLE SIMULATIONS AND  
CLUSTERS CONTINUE TO SHOW A WEAK SHORT-WAVE TROUGH CROSSING THE  
SOUTHERN CASCADES AND NORTHEASTERN CALIFORNIA. HOW FAR SOUTH AND  
DEEP THE TROUGH DIGS IS STILL IN QUESTION AS THE GEFS AND EC-ENS  
HAVE DIFFERING SOLUTIONS. THIS IS ALSO SEEN WITHIN THE CLUSTERS,  
WITH A COUPLE OF SIMULATIONS SHOWING A DEEPER TROUGH, WHILE THE  
OTHER THREE SHOW A RATHER WEAK WAVE CROSSING NORTHERN CALIFORNIA.  
CONSIDERING EVERYTHING, WE LOOK TO SEE A BRIEF CHANGE TO THE  
WEATHER ACROSS NORTHERN CALIFORNIA AND FAR NORTHWESTERN NEVADA  
INTO EARLY SATURDAY, WITH RAIN AND HIGH ELEVATION MIXED  
PRECIPITATION (SNOW LEVELS BETWEEN 8,000 TO 9,000 FEET) EXPECTED.  
TOTAL PRECIPITATION AMOUNTS LOOK TO BE BETWEEN A FEW HUNDREDTHS OF  
AN INCH JUST WEST OF THE LAKE TAHOE BASIN TO CLOSER TO A TENTH OF  
AN INCH ACROSS NORTHEASTERN CALIFORNIA AND NORTHWESTERN NEVADA.  
SHOWERS LOOK TO DIMINISH BY THE EVENING HOURS SATURDAY ACROSS THE  
NORTHERN SIERRA AND NORTHEAST CALIFORNIA, WITH A FEW LIGHT RAIN  
SHOWERS POSSIBLE ALONG THE COLD FRONT EAST INTO WESTERN NEVADA.  
TEMPERATURES LOOK TO REMAIN NEAR AVERAGE FOR THIS TIME OF YEAR  
SATURDAY AND SUNDAY.  
 
MONDAY INTO TUESDAY, ANOTHER SHORT-WAVE TROUGH MAY BRING OUR  
FIRST SHOT OF NOVEMBER WEATHER TO THE REGION. ONLY TWO OF THE FIVE  
ENSEMBLE CLUSTERS ARE IN AGREEMENT BRINGING RAIN AND VERY HIGH  
ELEVATION SNOW SHOWERS TO THE WESTERN SLOPES OF THE SIERRA, WITH  
VERY LITTLE IF ANY SPILLOVER EXPECTED INTO FAR WESTERN NEVADA.  
THIS IS DUE TO THE TROUGH LIFTING INTO THE PACNW AND AVOIDING A  
DIRECT HIT WITH THE SIERRA. WITH SUCH A LOW CONFIDENCE FORECAST,  
WE ONLY HAVE AT MOST 25-35% POPS NORTH OF US-50 INTO NORTHEASTERN  
CALIFORNIA FOR THE MONDAY INTO TUESDAY TIMEFRAME. WE'LL CONTINUE  
TO KEEP OUR EYES ON THIS ONE FOR ANY CHANGES.  
 
-JOHNSTON  
 

 
   
AVIATION
 
 
RATHER BENIGN WEATHER PATTERN IN PLACE THROUGH TODAY AND  
TOMORROW, RESULTING IN FAVORABLE CONDITIONS FOR AVIATION INTERESTS  
WITH PREVAILING VFR FOR THE NV TERMINALS. TRK AND TVL WILL  
EXPERIENCE FREEZING FOG EARLY TOMORROW MORNING WITH LIFR AND MVFR  
VSBY CARRIED IN THE TAFS, RESPECTIVELY. THIS WILL BREAK BY 16Z-17Z  
WITH VFR RETURNING THROUGH THE REMAINDER OF THE PERIOD.  
 
MOVING INTO THE WEEKEND, A WEAK LOW PRESSURE SYSTEM WILL WORK ITS  
WAY INTO NE CALIFORNIA AND NW NEVADA. THIS WILL BRING THE CHANCE  
FOR SHOWERS TO THE AREA, PRIMARILY NORTH OF INTERSTATE 80 FRIDAY  
NIGHT INTO SATURDAY MORNING. LOCAL FLIGHT RESTRICTIONS MAY BE  
POSSIBLE WITH THIS PRECIPITATION. HOWEVER, NO SNOWFALL IS  
ANTICIPATED DUE TO HIGH SNOW LEVELS.  
 
-DUSTIN  
 

 
   
REV WATCHES/WARNINGS/ADVISORIES
 
 
NV...NONE.  
CA...NONE.  

 
 

 
 
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/RENO  
 
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