840  
FXUS65 KREV 020958  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
258 AM PDT FRI JUN 2 2023  
   
SYNOPSIS
 
 
DRY CONDITIONS ARE EXPECTED TODAY, FOLLOWED BY INCREASING CHANCES  
FOR PRECIPITATION IN THE SIERRA AND WESTERN NV ON SATURDAY AND  
SUNDAY. TEMPERATURES WILL INCREASE ABOVE AVERAGE THIS WEEKEND,  
INCREASING SNOWMELT RATES. THE CHANCES FOR PRECIPITATION INCREASE  
BY MONDAY THROUGH AT LEAST THE MIDDLE OF NEXT WEEK, WITH TEMPERATURES  
RETURNING TO AVERAGE.  
 

 
   
DISCUSSION
 
 
CURRENT WATER VAPOR IMAGERY IS SHOWING A MUCH DRIER AIRMASS OVER  
THE REGION WITH A WEAK SHORTWAVE TROUGH CENTERED OVER NORTHERN  
NV. THE 6/1 AFTERNOON SOUNDING ALSO PICKED UP ON THIS NOTABLE  
DRYING, AS PRECIPITABLE WATER VALUES DECREASED BY ~0.30" COMPARED  
TO PRIOR DAYS. THE GOOD NEWS IS THAT TODAY LOOKS TO BE THE DRIEST  
DAY REGION-WIDE WE'VE HAD IN WELL OVER A WEEK! NO PRECIPITATION  
IS EXPECTED TODAY, ALONG WITH NORMAL TEMPERATURES AND LIGHT WINDS.  
 
LOOKING AT THE OVERALL EVOLUTION OF THE SYNOPTIC PATTERN THERE  
ARE TWO SEPARATE AREAS OF FOCUS; ONE IS OVER OUR AREA, AND THE  
OTHER IS TO THE SOUTH. BY SATURDAY THE AFOREMENTIONED SHORTWAVE  
TROUGH OVER NORTHERN NV MOVES EAST INTO UT, AS A SHORTWAVE RIDGE  
MOVES OVERHEAD. THIS RIDGE AXIS CONTINUES ITS EASTWARD TRACK ON  
SUNDAY INTO CENTRAL NV AS THE TROUGH MOVES NORTH INTO ID.  
MEANWHILE TO OUR SOUTH, THE ENSEMBLES ARE SHOWING AN UPPER LEVEL  
LOW PRESSURE MOVING JUST OFF THE SOCAL COAST BY SUNDAY NIGHT.  
EVENTUALLY, THE SOUTHERN UPPER LEVEL LOW PRESSURE WILL BECOME THE  
DOMINATE WEATHER MAKER INTO NEXT WEEK.  
 
FOR THIS WEEKEND, WITH RIDGING ALOFT TEMPERATURES WILL INCREASE A  
FEW DEGREES EACH DAY, RETURNING TO ABOVE AVERAGE FOR EARLY JUNE.  
AFTER ONE ENTIRE DAY OF DRY WEATHER REGION-WIDE, ISOLATED  
THUNDERSTORMS WILL RETURN TO THE SIERRA ON SATURDAY, WITH  
INCREASING CHANCES FOR PRECIPITATION INTO FAR WESTERN NV ON  
SUNDAY. THIS IS A COMBINATION OF AFTERNOON INSTABILITY AS WELL AS  
INCREASING MID-LEVEL MOISTURE PUSHING NORTHWARD DUE TO THE UPPER  
LEVEL LOW OVER SOCAL.  
 
ENSEMBLES SHOW THAT THE UPPER LEVEL LOW WILL MOVE INTO SOCAL ON  
MONDAY, THEN EVENTUALLY STALL AROUND SOUTHERN TO CENTRAL  
CALIFORNIA THROUGH THE MIDDLE OF NEXT WEEK. THIS FEATURE WILL  
INTRODUCE A DAILY CHANCE OF SHOWERS AND THUNDERSTORMS ALONG WITH  
SEASONAL TEMPERATURES.  
- MCKELLAR  
 

 
   
AVIATION
 
 
* MUCH LOWER STORM CHANCES (<5%), VFR CONDITIONS, AND TYPICAL  
AFTERNOON BREEZES WILL PREVAIL ACROSS ALL CA/NV TERMINALS TODAY.  
SATURDAY WILL SEE A RETURN OF ISOLATED SHOWERS AND THUNDERSTORMS  
OVER HIGHER MOUNTAIN AREAS, WITH THE BEST CHANCE (15-25%) FOR  
AFTERNOON AND EVENING THUNDER IN AND AROUND SIERRA TERMINALS.  
 
* WE'LL HAVE SLIGHTLY GREATER OVERALL COVERAGE FOR AFTERNOON  
SHOWERS AND THUNDERSTORMS ON SUNDAY. THERE IS A 25-35% CHANCE OF  
PRECIPITATION FOR THE SIERRA TERMINALS AND 15-25% CHANCE FOR  
THE WESTERN NV TERMINALS.  
 
* PERIODS OF PATCHY FOG AND ATTENDANT MVFR/IFR CONDITIONS ARE  
STILL POSSIBLE FOR KTRK THE NEXT FEW NIGHTS, PARTICULARLY  
BETWEEN THE 10Z-15Z TIMEFRAME.  
- MCKELLAR  
 

 
   
HYDROLOGY
 
 
WITH A DRIER AIRMASS MOVING INTO THE REGION INTO THIS WEEKEND,  
THE OVERALL RISK OF THUNDERSTORMS WILL REMAIN MOSTLY CONFINED TO  
THE SIERRA. SOME OF THESE STORMS HAVE THE RISK OF LOCALLY HEAVY  
RAIN, WHICH WILL BE PROBLEMATIC FOR BURN SCARS, STEEP CANYONS, AND  
SMALLER STREAMS IN THE SIERRA ARE AMONG THOSE AREAS MOST  
VULNERABLE TO FLASH FLOODING.  
 
WITH THE EXPECTED INCREASE IN TEMPERATURES, RIVER STAGES WILL RISE  
INTO THE WEEKEND. MODERATE FLOODING WILL PERSIST ALONG THE EAST  
FORK AND MAINSTEM WALKER RIVER, WITH ELEVATED FLOWS AND MINOR  
FLOODING FOR OTHER PORTIONS OF THE WALKER RIVER SYSTEM. ELEVATED  
FLOWS TO NEAR MINOR FLOOD STAGE WILL ALSO BE POSSIBLE ALONG  
PORTIONS OF THE EAST AND WEST FORKS OF THE CARSON RIVER. CONTINUE  
WITH RIVER SAFETY PRACTICES AND FOLLOW ANY RECOMMENDATIONS FROM  
LOCAL OFFICIALS. PROLONGED FLOOD CONCERNS REMAIN AS WE CONTINUE TO  
MELT THE RECORD SIERRA SNOWPACK.  
 
THE HUMBOLDT RIVER WILL BE ANOTHER MAINSTEM RIVER TO MONITOR AS  
ELEVATED FLOWS SLOWLY MIGRATE DOWNSTREAM. THE LATEST FORECAST AT  
IMLAY APPROACHES MINOR FLOOD STAGE BY SATURDAY MORNING.  
- MCKELLAR  
 

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

 
 

 
 
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