272  
FXUS65 KREV 271906  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
1206 PM PDT SAT MAY 27 2023  
   
SYNOPSIS  
 
DAILY SHOWERS AND THUNDERSTORMS (30-60% CHANCES) ARE FORECAST  
THROUGH THE HOLIDAY WEEKEND AND INTO NEXT WEEK. STRONGER STORMS  
MAY PRODUCE LOCALLY HEAVY RAINFALL, SMALL HAIL, GUSTY OUTFLOW  
WINDS, AND FREQUENT LIGHTNING. SNOWMELT WILL KEEP STREAMS  
RUNNING COLD AND FAST, WITH MAIN FLOOD CONCERNS FOR THE WALKER  
RIVER.  
 
 
   
DISCUSSION  
 
NO SIGNIFICANT CHANGES TO THE ONGOING FORECAST. PLAN ON DAILY  
AFTERNOON THUNDERSTORMS (30-60% CHANCES) THROUGH THE HOLIDAY AND  
INTO EARLY NEXT WEEK AS WELL AS ONGOING SNOW MELT IMPACTS.  
THUNDERSTORM IMPACTS EACH DAY WILL INCLUDE: LOCALLY HEAVY  
RAINFALL, SMALL HAIL, GUSTY AND ERRATIC OUTFLOW WINDS, AND  
FREQUENT LIGHTNING.  
 
TODAY: A CUT OFF LOW ACROSS THE PACIFIC NORTHWEST IS PUNTING A  
SHORTWAVE ACROSS NORTHERN CA/NV THIS AFTERNOON AND EVENING AND  
TRIGGERING CONVECTIVE ACTIVITY FOR AREAS ALONG AND NORTH OF  
INTERSTATE 80 TODAY. VISIBLE SATELLITE IMAGERY SHOWS AN EXPANSIVE  
AREA OF CUMULUS BUILDUPS WELL UNDERWAY WITH THUNDERSTORM  
INITIATION OCCURRING ACROSS NORTHERN LASSEN AND NORTHERN WASHOE  
COUNTIES. AREAS OF SHOWERS AND THUNDERSTORMS ARE ALREADY ONGOING  
ACROSS LASSEN AND WASHOE COUNTIES WITH A WEST TO EAST TRACK.  
OUTDOOR ENTHUSIASTS BE AWARE OF THE RAPIDLY CHANGING CONDITIONS  
AND BE PREPARED TO SHELTER IN A STURDY BUILDING OR VEHICLE IF  
YOU HEAR THUNDER. EVEN SMALL PEA-SIZED HAIL IS QUITE PAINFUL IF  
YOU GET STUCK OUTSIDE IN A STORM!  
 
REST OF THE HOLIDAY WEEKEND: THE CUT OFF LOW DROPS SOUTH ALONG  
THE CA COAST AND MEANDERS ABOUT CA FROM THIS WEEKEND INTO MIDWEEK  
NEXT WEEK. EAST SURFACE WINDS COMBINED WITH SOUTHERLY STEERING  
WILL RESULT IN DIRECTIONAL SHEAR ACROSS THE SIERRA AND WESTERN  
NEVADA ON SUNDAY. THE COMBINATION OF LOW TO MID LEVEL SHEAR,  
SURFACE INSTABILITY, AND UPPER LEVEL DIVERGENCE MAY PRODUCE  
STRONGER, LONGER-DURATION STORMS MIDDAY SUNDAY INTO THE EVENING,  
ESPECIALLY FOR STORMS THAT FORM ALONG AND SOUTH OF INTERSTATE 80.  
AS THE LOW LINGERS OFFSHORE, THUNDERSTORM POTENTIAL WILL SHIFT  
SLIGHTLY WITH THE BEST POTENTIAL (30-40% CHANCES) ALONG THE  
SIERRA, NORTHEAST CA, AND FAR WESTERN NV.  
 
GENERALLY WITH THUNDERSTORMS THIS WEEKEND INTO EARLY NEXT WEEK,  
WE COULD SEE LOCALIZED HEAVY RAINFALL RATES THAT MAY AGGRAVATE  
FLOODING IMPACTS IN SENSITIVE AREAS SUCH AS RECENT BURN SCARS,  
STEEP CANYONS, AND ALONG RIVERS AND CREEKS ALREADY RUNNING FAST  
AND HIGH FROM SPRING SNOWMELT.  
 
PLAN ON THE UNSETTLED PATTERN WITH ABOVE NORMAL PRECIPITATION  
CHANCES (DUE TO SHOWERS AND THUNDERSTORMS) APPEARS TO LINGER ON  
WITH THE WEST AS WE HEAD INTO EARLY JUNE. NO SIGNALS FOR BUILDING  
HIGH PRESSURE RIDGE FOR THE CA/NV REGION. -EDAN  
 
 
   
AVIATION  
 
A STEADY PATTERN OF SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS  
WILL BE POSSIBLE THROUGH THE WEEKEND. THERE WILL BE A 30-40% CHANCE  
FOR STORMS IMPACTING KTRK-KTVL AS WELL AS KRNO-CXP-KMEV THROUGH  
03Z THIS EVENING. STORMS MAY PRODUCE BRIEF HEAVY RAINFALL, WITH  
TERRAIN OBSCURATION, GUSTY AND ERRATIC OUTFLOW WINDS IN EXCESS OF  
40 KTS, AND SMALL HAIL. MORE WIDESPREAD SHOWER AND STORMS CHANCES  
WILL BE POSSIBLE SUNDAY AFTERNOON (40-50% CHANCE). OUTSIDE OF  
STORMS, CONDITIONS WILL BE VFR WITH SCATTERED TO BROKEN CUMULUS  
DECKS. PERIODS OF FOG WILL BE POSSIBLE OVERNIGHT AT KTRK FROM  
10-15Z. FUENTES  
 
 
   
HYDROLOGY  
 
NO SIGNIFICANT UPDATES OR CHANGES IN ONGOING FLOOD CONCERNS.  
HEADWATER FLOWS HAVE DIMINISHED A BIT WITH COOLER TEMPERATURES,  
AND CRESTS ARE SLOWLY MIGRATING DOWN MAINSTEM RIVERS.  
 
* WALKER: PROLONGED MINOR TO MODERATE FLOODING WILL CONTINUE  
ALONG THE EAST FORK AND MAIN-STEM OF THE WALKER RIVER. THE  
WALKER RIVER IN THE MASON VALLEY CONTINUES TO TREND SLIGHTLY  
DOWNWARD. VERY MINIMAL DECREASES IN FLOW ARE EXPECTED THIS  
WEEKEND, BUT IT WILL DEPEND ON RESERVOIR MANAGEMENT ADJUSTMENTS  
WHICH ARE INTENDED TO MAINTAIN STORAGE AND TO MITIGATE FUTURE,  
AND POTENTIALLY, HIGHER PEAKS.  
 
* CARSON: MINOR FLOOD IMPACTS MAY BE A CONCERN ALONG THE EAST AND  
WEST FORKS OF THE CARSON, BUT TRENDS ARE DOWN FROM EARLIER IN  
THE WEEK.  
 
* MONO COUNTY: KEEP A CLOSE EYE ON MONO COUNTY SMALL STREAMS  
WHICH HAVE BEEN RUNNING VERY HIGH.  
 
* THUNDERSTORMS: THUNDERSTORMS WILL CONTINUE TO BE A WILD CARD.  
UNSETTLED, STORM PATTERN CONTINUES FOR THE WEEKEND AND INTO NEXT  
WEEK. WITH SATURATED SOILS AND ELEVATED STREAMFLOWS, ADDITIONAL  
RAIN WILL RESULT IN RAPID RISES AND ENHANCED FLOODING  
POTENTIAL. THESE STORMS WILL BE MOST IMPACTFUL ALONG SMALLER  
CREEKS AND STREAMS, BUT COULD ALSO EXACERBATE PROBLEMS ALONG  
MAINSTEM RIVERS WHICH ARE ALREADY FLOODING OR ARE VERY CLOSE TO  
FLOOD IMPACT LEVELS. NOTE: RIVER FORECASTS ARE INCAPABLE OF  
INCORPORATING THESE SHORT DURATION HIGH INTENSITY RAIN EVENTS.  
 
-BARDSLEY/EDAN  
 
 
   
REV WATCHES/WARNINGS/ADVISORIES  
 
NV...NONE.  
CA...NONE.  
 
 
 
 
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