879
FXUS65 KREV 150912
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
212 AM PDT TUE APR 15 2025
KEY MESSAGES
* WARMER WEATHER CONTINUES THROUGH WEDNESDAY WITH SNOWMELT
RESULTING IN STREAMS RUNNING FAST AND COLD.
* AFTERNOON SHOWERS AND THUNDERSTORMS ARE POSSIBLE THROUGH MID-
WEEK WITH ISOLATED AREAS OF HEAVY RAINFALL POSSIBLE, ESPECIALLY
ON WEDNESDAY.
* A COLD FRONT BRINGS LIGHT MOUNTAIN SNOW, MORE THUNDERSTORMS,
GUSTY WINDS, AND COOLER WEATHER THURSDAY AND FRIDAY BEFORE A
WARMING AND DRYING TREND RETURNS EASTER WEEKEND.
DISCUSSION
AN UPPER RIDGE IN THE WESTERN US WILL BE SLOWLY PUSHED EAST WITH
THE APPROACH OF A CLOSED LOW TO CA. THEREFORE, EXPECT SEASONABLY
MILD WEATHER TO CONTINUE THROUGH TOMORROW. THIS WILL RESULT IN
AFTERNOON HIGHS CLIMBING TO THE MID-UPPER 70S IN WESTERN NV AND NE
CA, AND TO THE UPPER 50S-MID 60S FOR SIERRA VALLEYS. THIS WARMTH
WILL LEAD TO STREAMS AND RIVERS RUNNING FAST AND COLD DUE TO THE
SNOWMELT FROM THE SIERRA SNOWPACK.
THE MOVEMENT OF THE LOW TOWARDS THE SOUTHERN PORTIONS OF CA WILL
LEAD TO THE DEVELOPMENT OF A DEFORMATION ZONE OVER THE GREAT BASIN
TODAY INTO WEDNESDAY. THESE DYNAMICS COUPLED WITH RISING INSTABILITY
AS MOISTURE SLOWLY SEEPS IN LEADS TO SHOWERS AND THUNDERSTORMS.
CURRENTLY, WE HAVE A 15-30% CHANCE FOR SHOWERS AND THUNDERSTORMS
OVER THE SIERRA AND PORTIONS OF FAR WESTERN NV, INCLUDING MINERAL
COUNTY NORTH TO THE WASHOE VALLEY. BY WEDNESDAY, THE CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASES TO 30-60% ACROSS THE SAME
AREA. FURTHERMORE, DIFFLUENCE ALOFT COMBINED WITH SLOW MOTIONS IN
THE 700-500 MB LEVELS WILL LEAD TO SLOW MOVING STORMS. THIS IS
IMPORTANT BECAUSE, THE MAIN HAZARDS EXPECTED WITH ANY STORM WILL
BE OCCASIONAL LIGHTNING, GUSTY WINDS AND BRIEF DOWNPOURS. HOWEVER,
THE SLOW SPEED OF STORMS INCREASES THE RISK OF FLASH FLOODING UP
TO 5% AS THOSE BRIEF DOWNPOURS LAST LONGER IN ISOLATED AREAS.
THE CLOSED LOW WILL MERGE WITH A DESCENDING UPPER LEVEL TROUGH
FROM THE PACIFIC NW BY THURSDAY. THIS WILL BE ACCOMPANIED BY A
SURFACE COLD FRONT BRINGING GUSTY WINDS AND COLDER TEMPERATURES.
WINDS WILL BE GENERALLY FROM THE NORTH IN THE 20-30 MPH RANGE, AND
STRONGER OVER MOUNTAINS AND WIND PRONE AREAS, WITH GUSTS BETWEEN 35-45
MPH. THESE WINDS COULD CREATE CROSSWINDS IN WESTERN NV ALONG I-80
AND US-50, AND LIFT SOME PATCHY BLOWING DUST IN THE NV BASIN AND
RANGE. THE COLDER AIR WILL DROP SNOW LEVELS DOWN FROM NORTH TO
SOUTH DOWN TO 6 TO 7 KFT BY THURSDAY AFTERNOON. SNOW LEVELS
FURTHER DROP BY FRIDAY MORNING TO 4 TO 5 KFT. THEREFORE, THERE ARE
CHANCES FOR SNOW IN THE MOUNTAINS. SNOW ACCUMULATIONS WILL BE
GENERALLY LIGHT AND RESTRICTED TO THE HIGHEST ELEVATIONS AROUND
THE TAHOE BASIN SOUTH TO ALPINE COUNTY. HOWEVER, MONO COUNTY MAY
SEE A COUPLE OF INCHES ABOVE 8 KFT.
STARTING ON FRIDAY, A PROGRESSIVE PATTERN DEVELOPS AS AN UPPER
RIDGE SETTLES AGAIN OVER WESTERN US, WITH A SERIES OF WEAK
DISTURBANCES LIKELY PASSING NEAR OUR REGION EVERY OTHER DAY.
HOWEVER, THE TREND APPEARS TO BE WARMER AND DRIER THIS WEEKEND AND
EARLY NEXT WEEK.
-HC
AVIATION
VFR CONDITIONS CONTINUE THROUGH WEDNESDAY 12Z. THERE MAY BE A FEW
BRIEF PERIODS OF MVFR CONDITIONS IN THE SIERRA FROM KTRK DOWN TO
KMMH DUE TO -SHRA/-TSRA BETWEEN 20-03Z. THE CHANCE OF STORMS IS
15-30% IN THE AFOREMENTIONED AREA. SOME SHOWERS MAY EXTEND INTO
ADJACENT AREAS IN WESTERN NV (10-20%). MOUNTAIN OBSCURATIONS WILL
BE POSSIBLE ALONG AND IN THE VICINITY OF THE SIERRA THROUGH 03Z.
WINDS WILL BE GENERALLY FROM THE E AND SE AOB 10 KTS. HOWEVER,
GUSTS UP TO 25 KTS ARE POSSIBLE NEAR STORMS.
SIMILAR CONDITIONS ARE EXPECTED ON WEDNESDAY. HOWEVER, THE CHANCES
FOR STORMS AND CLOUD COVER INCREASES AREAWIDE.
-HC
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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