630  
FXUS65 KREV 022019  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
119 PM PDT THU OCT 2 2025  
   
KEY MESSAGES  
 
* THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE THROUGH  
FRIDAY AS THE LOW PRESSURE SYSTEM DROPS INTO THE REGION.  
 
* TEMPERATURES REMAIN BELOW AVERAGE THROUGH THE UPCOMING WEEK,  
WITH FRIDAY SEEING THE LOWEST TEMPERATURES ALONG WITH LIGHT SNOW  
ABOVE 8000 FT ON FRIDAY MORNING.  
 
* DRIER AND COOL CONDITIONS PREVAIL THIS WEEKEND THROUGH MUCH OF  
NEXT WEEK.  
 
 
   
DISCUSSION  
 
WE GOT A WET START THIS MORNING IN MANY AREAS, ESPECIALLY OVER  
THE SIERRA NEAR THE TAHOE BASIN. PORTIONS OF THE SIERRA HAVE  
RECEIVED AROUND 0.5-1.0 INCH OF RAIN INCLUDING THE SIERRA CREST  
AND PLUMAS COUNTY. ALL DUE TO THE UPPER LOW FINALLY MOVING INLAND  
THIS MORNING, WHILE PULLING A DECENT PLUME OF SUBTROPICAL  
MOISTURE RESULTING IN PWS INCREASING TO 0.7 TO 0.9 INCHES. THOSE  
PW VALUES ARE WAY TOO HIGH FOR THIS TIME OF THE YEAR. THERE WAS  
NOT A LOT OF INSTABILITY THIS MORNING WHICH IS WHY WE HAD NO  
LIGHTNING, BUT THIS AFTERNOON WE GET MARGINAL INSTABILITY MAINLY  
CLOSE TO THE SIERRA AND OVER THE BASIN & RANGE.  
 
THESE SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH  
MUCH OF THE OVERNIGHT HOURS. THE LATEST HREF AND CAMS PERSIST  
SHOWING STRONG BANDS OF NUMEROUS SHOWERS AND ISOLATED  
THUNDERSTORMS THIS AFTERNOON OVER THE TAHOE BASIN, THEN  
PROGRESSING INTO THE SIERRA FRONT THIS AFTERNOON THROUGH 6-8 PM.  
THE MAIN CONCERN WILL BE HEAVY RAIN OVER BURN SCARS AND URBAN  
AREAS, WHERE LOCALIZED FLOODING WILL BE THE MAIN IMPACT. HOWEVER,  
THE CAMS ARE SHOWING A LOT OF BREAKS AROUND THE SIERRA FRONT  
OVERNIGHT. SO, EVEN THOUGH WE HAVE HIGH POPS, UPWARDS OF 60%, THE  
OPPOSITE SCENARIO SHOWS NOT A LOT OF RAIN AFTER MIDNIGHT IN THE  
SIERRA FRONT.  
 
THE AREA OF CONCERN FOR HEAVY RAIN MOVES INTO THE NV BASIN AND  
RANGE AROUND 8-10 PM AND THROUGH THE REST OF THE OVERNIGHT HOURS.  
EFI AND OTHER MODELS THAT LOOK AT ANOMALIES ARE HITTING THE BASIN  
AND RANGE WITH SIGNIFICANT ACCUMULATIONS OF RAIN. THEREFORE, KEEP  
AN EYE FOR ANY LONG PERIODS OF HEAVY RAIN IN THOSE AREAS, AS THEY  
CAN POTENTIALLY LEAD TO MORE THAN JUST LOCALIZED FLOODING. AT  
LEAST WE HAVE SEEN THE SHOWERS MOVING QUITE FAST THIS MORNING, AND  
MODELS AGREE ON KEEPING SIMILAR MOTIONS TONIGHT, WHICH SHOULD  
HELP REDUCE SOME OF THE RISK FOR FLOODING.  
 
BY FRIDAY MORNING, WE SHOULD BE BEHIND THE AXIS OF THE TROUGH AND  
THE COLD FRONT. THIS WILL LEAD TO A COLDER MORNING WITH MORNING  
LOWS IN THE 40S UP TO 50F OVER WESTERN NV, AND THE 30S IN SIERRA  
COMMUNITIES. WE MAY GET SOME LIGHT SNOW BELOW AN INCH IN ELEVATIONS  
ABOVE 8000 FT, AND UP TO 3-5 INCHES NEAR THE PEAKS (ABOVE 9000  
FT) ON MONO COUNTY. OTHERWISE, WET CONDITIONS PERSIST FOR THE REST  
OF THE AREA. HOWEVER, THE RAIN AND ISOLATED STORMS WILL BE MORE  
SPORADIC AND SPOTTY IN NATURE LEADING TO A LOWER RISK FOR HEAVY  
RAIN.  
 
SATURDAY AND BEYOND, WE CLEAR OUT BEFORE SUNRISE. ALTHOUGH THE  
COOL WEATHER AND BELOW AVERAGE TEMPERATURES ARE EXPECTED TO  
PERSIST THROUGH MID-WEEK NEXT WEEK. HOWEVER, WE GET SOME GRADUAL  
WARMING AFTER TUESDAY BEHIND ANOTHER WEAK UPPER LEVEL SYSTEM.  
 
-HC  
 
 
   
AVIATION  
 
* GENERALLY VFR CONDITIONS CONTINUE THROUGH THE AFTERNOON. THE  
EXCEPTIONS WILL BE FOR KTRK/KTVL AS SHRA AND -TSRA MAY REDUCE  
CIGS AND VIS TO MVFR OR IFR WITH THE STRONGEST ACTIVITY.  
 
* LIGHT TO MODERATE RAINFALL WITH MVFR TO LOCAL IFR FOR WESTERN NV  
TERMINALS ARE LIKELY AFTER 18-20Z TO AROUND 10-12Z FRIDAY. LOW  
LEVEL CLOUD DECKS LEADING TO MOUNTAIN OBSCURATIONS IN THE SIERRA  
CONTINUE THROUGH FRIDAY. ADDITIONAL CHANCES FOR SHOWERS  
CONTINUE AREAWIDE INTO FRIDAY EVENING.  
 
* WINDS ARE OVERALL LIGHT FOR ALL TERMINALS TODAY, WITH SUSTAINED  
WINDS AROUND 10 KTS AND GUSTS TO 20 KTS. WATCH FOR GUSTY  
OUTFLOWS NEAR SHRA/-TSRA. SOME MINOR TURBULENCE AND LLWS IS  
EXPECTED THROUGH THIS EVENING. -MCKELLAR/HC  
 
 
   
REV WATCHES/WARNINGS/ADVISORIES  
 
NV...NONE.  
CA...NONE.  
 
 
 
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