413
FXUS65 KREV 240922
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
122 AM PST WED DEC 24 2025
KEY MESSAGES
* MOSTLY DRY WEATHER CONTINUES INTO THE EVENING WITH GUSTY WINDS
LINGERING OVERNIGHT.
* PERIODS OF HEAVY SIERRA SNOW, LOWER ELEVATION RAIN AND SNOW, AND
STRONG, GUSTY WINDS EXPECTED TONIGHT THROUGH FRIDAY.
* DRIER WEATHER RETURNS THIS WEEKEND AND CONTINUES INTO NEXT WEEK,
ACCOMPANIED BY CHILLY TEMPERATURES.
DISCUSSION
SNOW/WIND POTENTIAL TONIGHT - WEDNESDAY:
* AHEAD OF THE APPROACHING SYSTEM, WINDS ARE INCREASING ACROSS THE
INNER-BASINS WITH GUSTS UP TO 45-55 MPH AS OF THIS WRITING.
WINDS WILL STAY ELEVATED IN THE INNER BASINS INTO THE EARLY
MORNING, WITH GUSTS UPWARDS OF 60 MPH IN WIND PRONE AREAS (US-95
NEAR WALKER LAKE) AS WELL AS ANY E-W ORIENTATED ROADS. AS FOR
WINDS ELSEWHERE, THE RIDGETOPS ARE CURRENTLY GUSTING BETWEEN
60-70 MPH WEST OF LAKE TAHOE TO AROUND 40 MPH ON SLIDE MOUNTAIN.
WINDS WILL REALLY RAMP UP TODAY ON THE PEAKS, WITH GUSTS
BETWEEN 80-100 MPH LIKELY TODAY.
* THE FIRST IN A SERIES OF WINTER STORMS IS CURRENTLY MOVING INTO
THE EASTERN SIERRA. RADAR IMAGERY (AS OF 11PM) IS STARTING TO
PICK UP SOME LIGHT SHOWERS IN THE SIERRA. PRECIPITATION WILL
CONTINUE TO INCREASE IN INTENSITY THE REST OF TONIGHT INTO
CHRISTMAS EVE. AS THIS FIRST SYSTEM ROLLS THROUGH THE REGION,
THE HIGH-RESOLUTION MODELS AND HREF SHOW A BREAK IN THE
PRECIPITATION BETWEEN MID-MORNING AND THE EARLY EVENING FOR
EASTERN PLUMAS AND LASSEN COUNTY. PRECIPITATION IN THE TAHOE
BASIN MAY BECOME MORE SHOWERY IN NATURE BY 12 PM TO THE EARLY
EVENING. MEANWHILE, ALPINE AND MONO COUNTIES MAY NOT SEE A BREAK
TODAY. SPILLOVER SHOWERS WILL BECOME LIKELY FOR A MAJORITY OF
WESTERN NV TODAY THROUGH THE AFTERNOON, FOLLOWED BY A BREAK THIS
EVENING.
* THE SNOW LEVEL RADAR FROM COLFAX SHOWS CURRENT SNOW LEVELS
AROUND 8,000 FT, AND LOCAL SKI/TRAFFIC CAMERAS ARE SHOWING
SIMILAR CONDITIONS. AS FOR SNOW LEVELS TODAY, BY THE AFTERNOON
THEY WILL TUMBLE TO BETWEEN 6,000-7,000 FT IN THE TAHOE BASIN TO
AROUND 7,000-7,500 FT IN MONO COUNTY. BUT, BY THE EVENING THEY
WILL CONTINUE TO FALL TO AROUND 6,000 FT AREA-WIDE. AGAIN ONE
THING TO NOTE FOR TODAY IS IF WE HAVE HEAVIER PRECIPITATION
RATES, SNOW LEVELS MAY QUICKLY FALL 500-1000+ FT IN A SHORT
PERIOD. SNOW CHARACTER TODAY WILL BE THE CLASSIC SIERRA CEMENT
WITH SLR BETWEEN 8-10:1, AND SNOW RATES UPWARD OF 2" PER HOUR
ARE CONCEIVABLE.
SNOW/WIND POTENTIAL CHRISTMAS DAY TO FRIDAY:
* AFTER THE FIRST WAVE MOVES THROUGH CHRISTMAS EVE, THE NEXT
SYSTEM IS CLOSE ON ITS HEELS. BY CHRISTMAS MORNING, PERIODS OF
HEAVY SNOW WILL START IN THE SIERRA AND WILL CONTINUE INTO
FRIDAY. SNOW LEVELS BY THE AFTERNOON ARE AROUND 5,000-6,500 FT
AND BY THE EVENING THEY WILL BE AROUND 5,000 FT. INTO FRIDAY,
SNOW LEVELS ARE POSSIBLY AS LOW AS THE VALLEY FLOORS IN WESTERN
NV, BUT CONFIDENCE REMAINS LOW. THE HEAVIEST OF THE SNOW WILL
EVENTUALLY TAPER OFF LATE FRIDAY, WITH SNOW SHOWERS PERSISTING
IN THE SIERRA THROUGH MID-DAY SATURDAY. AS FOR WINDS, IT'S
LOOKING LIKE WE WILL SEE ANOTHER UPTICK IN WINDS IN WESTERN NV
BY AROUND MIDNIGHT TONIGHT THROUGH THE CHRISTMAS AFTERNOON.
WEEKEND OUTLOOK INTO NEW YEARS:
* THIS SECOND SYSTEM STILL LOOKS TO EXIT THE REGION BY FRIDAY.
TEMPERATURES THIS WEEKEND WILL FINALLY FEEL LIKE WINTER. HIGHS
WILL BE IN THE 30S TO LOW 20S IN THE SIERRA. LOW TEMPERATURES
WILL TUMBLE INTO THE SINGLE DIGITS IN THE SIERRA TO EVEN TEENS
IN WESTERN NV. I THINK IT'S ABOUT TIME! THESE 60S ARE GETTING
OLD. ANOTHER LOW MAY IMPACT THE REGION BY NEW YEARS, BUT LOW
CONFIDENCE AT THIS TIME. -MCKELLAR
- FOR DETAILS ON THE WINTER STORM WARNING, PLEASE
VISIT:WWW.WEATHER.GOV/REV/WINTER
- ADDITIONAL FORECAST INFORMATION CAN BE FOUND AT
WWW.WEATHER.GOV/REV
- IF YOU'RE PLANNING ON GOING OUT TO THE BACK COUNTRY IN THE
EASTERN SIERRA, PLEASE VISIT WWW.WEATHER.GOV/REV/AVALANCHE
AVIATION
NV TERMINALS WILL SEE VICINITY SHOWERS EARLY THIS MORNING WITH
30% PROBABILITY OF A SHOWER PASSING OVER THE SITE AND LOWERING
VISIBILITIES TO MVFR THROUGH 24/14Z. THE SITES THEN WILL HAVE
STEADY RAINFALL STARTING AROUND 24/14Z THAT WILL CAUSE MVFR
VISIBILITIES AND CEILINGS. WHILE CONDITIONS ARE EXPECTED TO
IMPROVE BY AROUND 25/01Z, LINGERING SHOWER CHANCES CONTINUE
THROUGH THE EVENING. A SECOND ROUND OF PRECIPITATION FROM THIS
SYSTEM IS FORECAST TO BEGIN EARLY CHRISTMAS DAY WHICH HAS
POTENTIAL TO TRANSITION TO SNOW AT THE NV TERMINALS THOUGH
ACCUMULATIONS LOOK TO BE LIGHT AT THIS TIME. LLWS AND GUSTY WINDS
GENERALLY OUT OF THE SOUTH ARE TO BE EXPECTED TODAY GOING INTO
TOMORROW.
AS FOR SIERRA TERMINALS, SHOWERS HAVE ALREADY STARTED THIS MORNING
CAUSING MVFR CONDITIONS. AS SNOW LEVELS CONTINUE TO DROP THROUGH
THE DAY, P-TYPE WILL CHANGE TO SNOW LATER THIS MORNING WHICH WILL
ALLOW FOR IFR VISIBILITIES TO OCCUR AT ALL SIERRA TAF SITES.
DURING THE AFTERNOON, KTRK/KTVL MAY SEE RAIN MIX INTO THE SNOW
BEFORE RETURNING TO ALL SNOW GOING INTO THE NIGHT AND INTO
CHRISTMAS DAY. THERE DOESN'T LOOK TO BE MUCH OF A BREAK IN
PRECIPITATION AT SIERRA TERMINALS TODAY OR TOMORROW ALLOWING FOR
SUB-VFR CONDITIONS TO CONTINUE. LLWS IS TO BE EXPECTED AT ALL
SIERRA TAF SITES WITH GUSTY WINDS OUT OF THE SOUTH-SOUTHWEST
TODAY. -078
HYDROLOGY
FLOODING CONCERNS WILL BE RENEWED LATE TUESDAY THROUGH WEDNESDAY
WHEN THE NEXT STORM BRINGS ADDITIONAL RAIN BEFORE EVENTUALLY
TRANSITIONING TO SNOW. AREAS OF CONCERN WILL BE URBAN AND POOR
DRAINAGE AREAS, AND CREEKS AND STREAMS FROM LAKE TAHOE THROUGH
LASSEN COUNTY. THE GREATEST FLOODING CONCERN IS FOR RIVERS AND
STREAMS DRAINING LARGE WATERSHEDS BELOW ABOUT 6,500'. THIS INCLUDES
MANY STREAMS IN SIERRA, PLUMAS AND LASSEN COUNTIES AND THE SUSAN
RIVER.
MINOR FLOODING IS POSSIBLE, BUT NOT CURRENTLY FORECAST, FOR THE
SUSAN RIVER ON CHRISTMAS EVE. THE RUNOFF IN THE SUSAN AND OTHER
SIMILAR DRAINAGES WILL BE VERY SENSITIVE TO THE DURATION OF RAIN
VS. SNOW, AND ANY DELAY IN THE TRANSITION TO SNOWFALL COULD
EASILY PUSH THE SUSAN RIVER HIGHER. FOR EXAMPLE, A SIMULATION WITH
JUST A 500' INCREASE IN THE RAIN/SNOW LINE LEADS TO A SECOND
SECOND PEAK ON THE SUSAN RIVER APPROACHING MODERATE FLOOD STAGE
ON CHRISTMAS DAY. NO OTHER MAIN-STEM RIVERS ARE FORECAST TO
FLOOD, BUT SLOW RISES AND HIGH FLOWS ARE EXPECTED ON THE PIT
RIVER BELOW CANBY, AND MIDDLE FORK OF THE FEATHER NEAR PORTOLA.
ENHANCED RUNOFF AND SEDIMENT TRANSPORT INCLUDING ROCK FALL ARE
POSSIBLE WITHIN AND BELOW RECENT BURN AREAS. POST-FIRE DEBRIS FLOWS
ARE NOT EXPECTED.
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
-BARDSLEY
REV WATCHES/WARNINGS/ADVISORIES
NV...WINTER STORM WARNING UNTIL 10 AM PST FRIDAY NVZ002.
WIND ADVISORY UNTIL 7 AM PST WEDNESDAY NVZ001-004.
CA...FLOOD WATCH THROUGH WEDNESDAY EVENING CAZ071.
WINTER STORM WARNING UNTIL 10 AM PST FRIDAY CAZ071>073.
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