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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