027
FXUS65 KREV 121022
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
222 AM PST WED NOV 12 2025
KEY MESSAGES
* WARM AND DRY WEATHER CONTINUES WITH INCREASING WINDS POSING
TRAVEL AND RECREATION IMPACTS THIS AFTERNOON.
* A WINTER STORM BRINGS GUSTY WINDS, VALLEY RAIN, AND SIERRA SNOW
ON THURSDAY, RESULTING IN MORE TRAVEL AND RECREATION IMPACTS.
* PERIODS OF UNSETTLED WEATHER ARE POSSIBLE THROUGH THE WEEKEND
AND NEXT WEEK.
DISCUSSION
THE UPPER RIDGE IS SLOWLY LEAVING THE AREA TODAY AND AS IT DOES
SOME CLOUDS MOVE IN RESULTING IN SLIGHTLY COOLER TEMPERATURES
THIS AFTERNOON COMPARED TO YESTERDAY. THE UPPER LOW THAT WE HAVE
BEEN ADVERTISING OVER THE LAST FEW DAYS IS MOVING CONSIDERABLY
SLOWER. IN RESPONSE, WINDS WILL NOT GET AS STRONG AS ORIGINALLY
EXPECTED THIS AFTERNOON. ANYWAY, GUSTS OF 20-30 MPH ARE LIKELY
ACROSS MUCH OF THE AREA, UP TO 40 MPH IN WIND PRONE AREAS AND TO
50-60 MPH IN SIERRA RIDGES. VALLEY WINDS DECREASE OVERNIGHT WHILE
RIDGE WINDS CONTINUE TO STRENGTHEN AS THE UPPER LEVEL LOW STARTS
TO COME ONSHORE TONIGHT INTO TOMORROW MORNING. WINDS WILL BRING
OUTDOOR RECREATION AND TRAVEL IMPACTS IN THE AFTERNOON HOURS.
THIS UPPER LOW HAS BEEN A VERY DIFFICULT SYSTEM TO FORECAST, AND
UP TO THIS TIME OUR CONFIDENCE IN THE FORECAST IS LOW. SO BARE
WITH US. THE PATH OF THE LOW IS NOW TAKING A MORE SOUTHERLY
TRAJECTORY ADVECTING WARM AIR TOWARD US WHICH HAS OVERALL RAISED
SNOW LEVELS TO 9000+ FT AREAWIDE. THEY NOW APPEAR TO DROP BELOW
8000 FT BY THURSDAY NIGHT INTO FRIDAY MORNING. FURTHERMORE, CAMS
INDICATE THAT WE WILL BE BLOCKED FROM MOST OF THE MOISTURE WITH
THE CORE OF THE PRECIPITATION FALLING WEST OF THE SIERRA CREST.
THE ENSEMBLE MEMBERS OF THE GFS AND ECMWF HAVE BEEN SHOWING A
TREND OVER THE LAST FEW MODEL RUNS OF WARMER TEMPERATURES
RESULTING IN THE LIKELY PRECIPITATION TYPE TO BE RAIN RATHER THAN
SNOW IN PORTIONS OF THE SIERRA.
AT THE MOMENT, WE DECIDED TO CANCEL THE WINTER WEATHER ADVISORY
FOR LASSEN AND PLUMAS COUNTIES AS SNOW LEVELS ARE EXPECTED TO BE
ABOVE 7000-8000 FT THROUGH THURSDAY EVENING. A FEW INCHES OF SNOW
(1-3" AT THE MOST) ARE POSSIBLE ABOVE 7000 FT IN ISOLATED
LOCATIONS. THE WINTER WEATHER ADVISORY FOR THE TAHOE BASIN HAS
BEEN UPDATED TO REFLECT THIS CHANGE, AND IT NOW STARTS AT 1 PM
THURSDAY WITH THE SLOWER MOTION AND HIGHER SNOW LEVELS. THE
PROBABILITY FOR SNOW ABOVE 6 INCHES HAS DROPPED TO 5-50% ABOVE
8000 FT, AND LIKELY 1-3 INCHES OF SNOW AT PASS LEVELS BETWEEN
7500-8000 FT. THE WINTER STORM WARNING FOR MONO COUNTY HAS
REMAINED MOSTLY THE SAME, BUT WE HAVE INCREASED THE ELEVATION OF
THE SNOW TO ABOVE 9000 FT WHERE THERE IS A 40-80% CHANCE OF
EXCEEDING A FOOT OF SNOW, AND CHANGED THE START TIME TO 1 PM AS
WELL.
SO, WITH THE NEW TRAJECTORY OF THE LOW AND THE MOUNTAINS BLOCKING
MOST OF THE SPILLOVER, WE ARE LOOKING AT RAIN SHOWERS TO BE
MOSTLY CONFINED TO AREAS CLOSE TO THE SIERRA, NE CA AND THE SIERRA
FRONT. RENO AND THE QUAD COUNTIES MAY OBSERVE UP TO 0.1-0.3
INCHES, WHILE NE CA MAY GET 0.2-0.6 INCHES, AND THE SIERRA AND
HIGHER ELEVATIONS OF AREA MOUNTAINS BETWEEN 0.5-1.5 INCHES OF
LIQUID EQUIVALENT (RAIN OR SNOW). THE PROBABILITY OF EXCEEDING AN
INCH OF RAIN FOR SIERRA COMMUNITIES IS 10-60% WITH THE HIGHER
PROBS TO LOCATIONS CLOSER TO THE SIERRA CREST.
WINDS HAVE ALSO COME DOWN TOO WITH THE LATEST MODEL ITERATIONS.
THE CHANCES OF EXCEEDING 45 MPH ARE NOW 10-60% ACROSS MOST AREAS.
THE STRONGEST WINDS ARE STILL EXPECTED OVER WIND PRONE AREAS AND
SIERRA RIDGES, WHERE GUSTS OF 55 MPH HAVE A 10-50% OF EXCEEDING
THAT MAGNITUDE. REGARDLESS, IT WILL STILL BE A WINDY DAY, JUST NOT
AS STRONG AS INITIALLY EXPECTED, WITH A LOW PROBABILITY OF
ISSUANCE OF WIND ADVISORIES FOR WESTERN NV AND NE CA.
ACTIVE WEATHER APPEARS TO PERSIST ON FRIDAY INTO EARLY NEXT WEEK.
HOWEVER, THE RISK OF SIGNIFICANT WEATHER APPEARS TO BE MINOR, BUT
LOW CONFIDENCE IN THE FORECAST PERSISTS DUE TO MODERATE TO HIGH
UNCERTAINTY BETWEEN ENSEMBLES FOR THE PATH OF THE SUBSEQUENT
DISTURBANCES THIS WEEKEND AND EARLY NEXT WEEK. FOR NOW, THE MOST
LIKELY SCENARIO IS COOLER TEMPERATURES WITH BREEZY RIDGES, AND
OCCASIONAL PERIODS OF VALLEY RAIN AND MOUNTAIN SNOW.
-HC
AVIATION
WIDESPREAD VFR CONDITIONS PERSIST TODAY. THE MAIN EXCEPTION
CONTINUES AT KTRK BETWEEN 12-15Z THIS MORNING WITH PERIODS OF
PATCHY FZFG LEADING TO IFR/LIFR CONDITIONS. VFR CONDITIONS START
TO DROP TO MVFR TO IFR CONDITIONS DUE TO SHRA/SHSN AND MOUNTAIN
OBSCURATIONS BY 15-18Z THURSDAY IN THE SIERRA AND NE CA.
SW FL100 WINDS OF 30-40 KTS CONTINUE, WHICH MAY RESULT IN LLWS
AND MINOR MOUNTAIN WAVE TURBULENCE IMPACTS AT KTRK-KTVL AND
PERHAPS KRNO-KCXP-KMEV THROUGH 20Z THIS MORNING. SURFACE WINDS
AFTER 20Z BECOME FROM THE SW GUSTS OF 20-25 KTS AT ALL TERMINALS.
WINDS ALOFT INTENSIFY IN CONCERT WITH A WEAKENING OF SURFACE
WINDS WEDNESDAY EVENING, RENEWING LLWS AND MOUNTAIN WAVE
TURBULENCE CONCERNS THROUGH THURSDAY.
-SALAS/HC
FIRE WEATHER
SOUTHWEST WINDS HAVE TRENDED LOWER IN THE LAST FEW MODEL RUNS
LIMITING THE RISK OF FIRE WEATHER CONDITIONS THIS AFTERNOON IN THE
CHALFANT VALLEY AND VICINITY. ANYWAY, OCCASIONAL GUSTS OF 20-30
MPH ARE LIKELY THIS AFTERNOON ALONG WITH LOW HUMIDITIES. GUSTS
DECREASE OVERNIGHT, BUT RETURN ON THURSDAY WITH HIGHER HUMIDITIES
FURTHER DECREASING ANY FIRE CONCERNS.
-HC
REV WATCHES/WARNINGS/ADVISORIES
NV...WINTER WEATHER ADVISORY FROM 1 PM THURSDAY TO 7 AM PST FRIDAY
NVZ002.
CA...WINTER WEATHER ADVISORY FROM 1 PM THURSDAY TO 7 AM PST FRIDAY
CAZ072.
WINTER STORM WARNING FROM 1 PM THURSDAY TO 7 AM PST FRIDAY
CAZ073.
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