816
FXUS65 KREV 250944
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
144 AM PST THU DEC 25 2025
KEY MESSAGES
* WINTER STORMS WILL BRING PERIODS OF HEAVY SIERRA SNOW, SIGNIFICANT
MOUNTAIN TRAVEL DISRUPTIONS, AND GUSTY WINDS THROUGH FRIDAY.
* SNOW IMPACTS MAY SPREAD INTO WESTERN NEVADA FOOTHILLS CHRISTMAS
NIGHT INTO FRIDAY MORNING.
* DRY WEATHER RETURNS THIS WEEKEND INTO EARLY NEXT WEEK WITH COLD
TEMPERATURES AND GUSTY NORTHEAST WINDS ALONG SIERRA RIDGES.
DISCUSSION
LOCATIONS ACROSS THE SIERRA WILL BE WAKING UP TO A WHITE CHRISTMAS
THIS MORNING. PER NWS DEFINITION, A "WHITE CHRISTMAS" CONSTITUTES
AT LEAST 1 INCH OF SNOW BY 7AM CHRISTMAS MORNING. ASSUMING SNOW
STICKS AROUND, SIERRA FRONT COMMUNITIES MIGHT BE ABLE TO JUMP IN
ON THE FUN, AS WELL! HOWEVER, TEMPERATURES ACROSS THE SIERRA FRONT
HAVE RISEN ABOVE FREEZING TONIGHT, DUE TO LINGERING CLOUD COVER.
THIS MIGHT BE JUST ENOUGH TO MELT MOST OF THE SNOW THAT FELL
YESTERDAY EVENING.
IN THE SHORT TERM, WE'RE EXPECTING TWO WAVES OF HEAVY SNOW. THE
FIRST WAVE WILL ARRIVE THIS MORNING BY DAYBREAK, CONTINUING
THROUGH UNTIL NOON ACROSS THE SIERRA. NOTE, THOUGH, THAT SNOW
SHOWERS ARE EXPECTED ALL DAY, THIS WILL JUST BE THE PERIOD OF
HEAVIEST SNOW. W NV SITES BELOW 5500 FEET WILL LIKELY SEE RAIN
DURING THIS SAME TIMEFRAME. HOWEVER, SNOW LEVEL FORECASTS HAVE
BEEN ALL OVER THE PLACE THIS WEEK; WE DID GET SNOW IN RENO,
AFTER ALL. IF SKIES CLEAR OUT BY EARLY MORNING AND THOSE
TEMPERATURES DROP ENOUGH, WE COULD SEE ANOTHER ROUND OF SNOW FOR W
NV VALLEYS. THOUGH, FORECASTER CONFIDENCE ON THIS REMAINS LOW.
THE SECOND WAVE OF HEAVY SNOW WILL ARRIVE LATE TONIGHT THROUGH
EARLY FRIDAY MORNING. THIS WILL BE THE BEST TIME FRAME FOR
ACCUMULATING SNOW IN RENO AND OTHER SIERRA FRONT COMMUNITIES WITH
SNOW LEVELS BELOW VALLEY FLOORS. WITH SUCH LOW SNOW LEVELS, WE
COULD SEE ACCUMULATIONS OF AT LEAST A COUPLE INCHES ACROSS
FOOTHILL COMMUNITIES, UP IN NORTHERN WASHOE COUNTY, AND ALONG SOME
OF THE MOUNTAINS IN THE BASIN AND RANGE. RIGHT NOW, THERE IS A 30%
CHANCE OF AT LEAST 2 INCHES OF SNOW IN VIRGINIA CITY BY FRIDAY
MORNING.
IT'S NOT W NV AND THE SIERRA WITHOUT THE TALK OF GUSTY WINDS.
WINDS WILL BE JUST ABOVE OUR TYPICAL AFTERNOON BREEZES WITH GUSTS
UP TO 35-40 MPH IN THE BASIN AND RANGE TODAY. AS SUCH, A WIND
ADVISORY HAS BEEN ISSUED. PLEASE SEE THE PRODUCT FOR MORE DETAILS.
MEANWHILE, GUSTS ACROSS THE SIERRA FRONT WILL BE BETWEEN 30 AND
35 MPH WHILE RIDGETOPS WILL SEE GUSTS OF 80-100 MPH.
WITH ALL OF THESE ITEMS IN MIND, IT'S WORTHY TO NOTE THAT TRAVEL
ACROSS MUCH OF THE AREA, THE SIERRA IN PARTICULAR, WILL BE VERY
DIFFICULT OVER THE NEXT TWO DAYS. SNOWFALL RATES WILL RANGE UP TO
4"/HR AT TIMES (PLEASE SEE THE AVALANCHE DISCUSSION BELOW FOR
MORE DETAILS). GUSTY WINDS MAY BRING VISIBILITY REDUCTIONS AS WELL
AS DIFFICULT TRAVEL FOR HIGH PROFILE VEHICLES ALONG WIND PRONE
LOCATIONS. WIDESPREAD CHAIN CONTROLS WILL BE LIKELY WITH THE
POSSIBILITY FOR ROAD CLOSURES. FLIGHTS MAY BE IMPACTED, AS WELL,
DUE TO TURBULENCE. CHECK THE FORECAST BEFORE YOU GO, AS WELL AS
NV ROADS AND CALTRANS QUICKMAP FOR ROAD CONDITIONS IF YOU MUST
TRAVEL.
SATURDAY AND BEYOND, RIDGING SETTLES BACK INTO PLACE. THIS WILL
BRING DRY AND "WARM" CONDITIONS THROUGH THE END OF 2025. HOWEVER,
LONG RANGE GUIDANCE HINTS AT ANOTHER SYSTEM RIGHT AROUND NEW
YEARS. STAY TUNED!
-GIRALTE
AVIATION
MVFR WITH PERIODS OF IFR CONDITIONS LIKELY FOR KRNO/KCXP/KMEV
THROUGH MUCH OF TODAY. IFR CONDITIONS EXPECTED DUE TO -RA, WITH
POSSIBLE -RASN AS WELL. IFR/LIFR CONDITIONS EXPECTED FOR MUCH OF
THE FORECAST PERIOD FOR KTRK/KTVL/KMMH DUE TO HEAVY SN. SNOW WILL
BE WET IN CHARACTER, WITH A 50%/80% CHANCE OF RUNWAY ACCUMULATIONS
OF 6+ INCHES BY THURSDAY AFTERNOON FOR KTVL/KMMH, RESPECTIVELY.
FOR KTRK, THERE IS A 40% CHANCE OF ACCUMULATIONS GREATER THAN 3
INCHES BY THE SAME TIME.
MOUNTAIN OBSCURATIONS AND LLWS WILL IMPACT ALL TAF SITES THROUGH
THE PERIOD, AS WELL. GUSTS UP TO 30 KTS EXPECTED FOR SIERRA FRONT
TERMINALS, WITH GUSTS UP TO 25 KTS FOR SIERRA TERMINALS.
DO NOTE THAT SNOW LEVELS HAVE BEEN FLUCTUATING TONIGHT, BRINGING
REPORTS OF -RA/-RASN TO SIERRA TERMINALS. OUTSIDE OF THE HEAVIEST
PRECIPITATION PERIODS, SNOW LEVELS MAY BRING MORE LIQUID THAN
CURRENTLY ADVERTISED.
-GIRALTE
AVALANCHE
IMPACTS FROM HEAVY, WET SNOW AND STRONG GUSTY WINDS EXPECTED
ACROSS ALL AVALANCHE CENTER TERRAIN THROUGH FRIDAY.
* SWE, SLRS, AND SNOW LEVELS: FOR THE TAHOE BASIN, SWE UP TO 4"
ALONG THE HIGHEST PEAKS, OTHERWISE 2.5-3". LOCALLY LOWER AMOUNTS
AS YOU PROGRESS SOUTHWARD INTO BAC AND ESAC TERRAIN (UP TO 3.5"
ALONG THE HIGHEST PEAKS NEAR MAMMOTH, WITH 2-3" ELSEWHERE). SLRS
WILL RANGE FROM 8-10:1, THOUGH, THOSE MIGHT RISE TO 12:1 NEAR
THE END OF THE SYSTEM (FRIDAY AFTERNOON) AS DRIER AIR TRIES TO
MOVE IN. SNOW LEVELS THIS WEEK HAVE BEEN HARD TO PREDICT, THOUGH
THEY SHOULD REMAIN AROUND 5500' FOR SAC TERRAIN, WITH 6000' FOR
BAC TERRAIN, AND ~6250' FOR ESAC. SNOW LEVELS WILL DROP
OVERNIGHT, WITH LEVELS BELOW 5500' ACROSS THE SIERRA.
* SNOWFALL TOTALS AND RATES: AT LAKE LEVEL, 8-10" OF SNOW EXPECTED
IN THE NEXT TWO DAYS, WITH AN ADDITIONAL 3-5 FEET POSSIBLE AT
THE HIGHEST PEAKS. EXPECT SIMILAR TOTALS ACROSS MUCH OF THE
SIERRA DOWN INTO MONO COUNTY, WITH UP TO 2 FEET ALONG US-395.
SNOWFALL RATES OF 1-2"/HR FOR SAC TERRAIN, EXCEPT FOR UP TO
3"/HR DURING THE MOST INTENSE PERIODS (MENTIONED IN THE
DISCUSSION ABOVE). BAC AND ESAC TERRAIN WILL SEE OF 1.5-2.5"/HR
WITH UP TO 4"/HR RATES DURING THE MOST INTENSE PERIODS.
* RIDGETOP GUSTS: WSW GUSTS OF 80-100 MPH TODAY, SHIFTING MORE
WESTERLY WITH GUSTS UP TO 75 MPH FRIDAY.
-GIRALTE
HYDROLOGY
THE SUSAN RIVER NEAR SUSANVILLE CRESTED ABOVE MINOR FLOOD STAGE LATE
YESTERDAY MORNING FOR THE SECOND TIME THIS WEEK. THE FLOOD WAVE
WILL TAKE 12-24 HOURS TO MAKE IT'S WAY DOWNSTREAM TOWARDS
LITCHFIELD AND HONEY LAKE.
UNFORTUNATELY, WE ARE NOT QUITE DONE WITH THE FLOOD RISK ON THE
SUSAN RIVER. ADDITIONAL RAIN EARLY THIS MORNING BEFORE THE
EXPECTED TRANSITION TO SNOW WILL BRING RISES TO THE RIVER AGAIN.
JUST HOW HIGH IS A DIFFICULT FORECAST AS IT WILL DEPEND ON HOW
MUCH RAIN OCCURS, AND HOW QUICKLY THE RAIN SNOW ELEVATION DROPS.
THE CURRENT FORECAST GUIDANCE DOES NOT PREDICT A THIRD CREST ABOVE
FLOOD STAGE THIS WEEK, BUT DUE TO ALL THE UNCERTAINTIES OUTLINED
ABOVE, I CERTAINLY WOULD NOT RULE OUT THE POSSIBILITY.
IN OTHER AREAS, HIGH FLOWS ARE ONGOING AND EXPECTED TO CONTINUE,
ESPECIALLY IN WATERSHED PRIMARILY DRAINING TERRAIN BELOW ABOUT
6500 FEET. MINOR FLOODING IS POSSIBLE WITH PROLONGED PERIODS OF
HEAVY RAIN, ESPECIALLY IN LOW LYING AND POOR DRAINAGE AREAS TODAY
INTO TOMORROW MORNING.
BY MID-DAY TODAY WE SHOULD BE DONE WITH NEW FLOODING CONCERNS,
BUT HIGH FLOWS WILL TAKE MANY HOURS TO MAKE THEIR WAY DOWNSTREAM
THROUGH THE LOWER REACHES OF MAIN-STEM RIVERS.
THE RIVER FORECAST CENTER WILL BE EXTENDING HOURS THIS WEEK AND
ISSUING ADDITIONAL FORECASTS FOR RIVERS WHERE FLOODING IS
EXPECTED. CHECK FOR UPDATED RIVER FORECASTS AT: WWW.CNRFC.NOAA.GOV
-TIM/GIRALTE
REV WATCHES/WARNINGS/ADVISORIES
NV...WIND ADVISORY FROM 4 AM TO 10 PM PST THURSDAY NVZ001-004-005.
WINTER STORM WARNING UNTIL 10 AM PST FRIDAY NVZ002.
WINTER WEATHER ADVISORY FROM 4 AM THURSDAY TO 4 AM PST FRIDAY
NVZ003.
CA...WIND ADVISORY FROM 4 AM TO 10 PM PST THURSDAY CAZ070.
FLOOD WATCH UNTIL 10 PM PST THIS EVENING CAZ071.
WINTER STORM WARNING UNTIL 10 AM PST FRIDAY CAZ071>073.
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