650
FXUS65 KREV 202023
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1223 PM PST FRI DEC 20 2024
SYNOPSIS
* QUICK-MOVING STORMS THIS WEEKEND WILL BRING STRONGER WINDS ON
SATURDAY, WITH LIGHT RAIN AND HIGH ELEVATION SNOW SHOWERS.
* THE BEST WINDOW FOR HOLIDAY TRAVEL CONTINUES TO BE MONDAY,
BEFORE ANOTHER STORM BRINGS WINTER TRAVEL IMPACTS FOR THE SIERRA
ON TUESDAY.
* ADDITIONAL WEATHER SYSTEMS WITH LOWERING SNOW LEVELS ARE
POSSIBLE LATE NEXT WEEK AFTER CHRISTMAS DAY.
DISCUSSION
WIND GUSTS CONTINUE TO INCREASE OVER THE SIERRA, AS THIS WEEK'S
STAGNANT RIDGE PATTERN BREAKS DOWN WITH MULTIPLE QUICK MOVING
WEATHER SYSTEMS PASSING THROUGH CA/NV FOR THE UPCOMING WEEK.
THE FIRST STORM WILL ARRIVE SATURDAY, WITH THE PRIMARY IMPACT
BEING A ROUND OF STRONGER WINDS. 700 MB FLOW INCREASES TO NEAR 60
KT OVER THE SIERRA CREST NEAR TAHOE FROM LATE MORNING-MID
AFTERNOON, WHICH WOULD YIELD GUSTS OF 100+ MPH OVER SIERRA
RIDGES. HIGH RESOLUTION GUIDANCE INDICATES A POTENTIAL DOWNSLOPE
SIGNATURE THAT COULD BRING A 3-6 HOUR PERIOD WITH ENHANCED GUSTS
OF 45-55 MPH MIXING DOWN TO THE TAHOE BASIN, AND THE US-395/I-580
CORRIDOR FROM EASTERN LASSEN COUNTY SOUTHWARD ACROSS FAR WESTERN
NV. WIND ADVISORIES ARE NOW IN PLACE FOR THESE AREAS ON SATURDAY.
WHILE WINDS WILL EASE UP IN LOWER ELEVATIONS SATURDAY EVENING,
RIDGE-LEVEL WIND GUSTS UP TO 75 MPH WILL PERSIST THROUGH THE REST
OF THE WEEKEND.
ALONG WITH THE WINDS, BURSTS OF SHOWERY PRECIPITATION WILL REACH
NORTHEAST CA AND THE SIERRA AROUND TAHOE BY MID-LATE SATURDAY
MORNING AND CONTINUE THROUGH THE AFTERNOON. ADDITIONAL ROUNDS OF
LIGHTER PRECIPITATION ARE PROJECTED TO REACH THESE SAME AREAS
SUNDAY MORNING AND POSSIBLY SUNDAY EVENING. RAIN AND SNOW TOTALS
WILL BE MODEST WITH THESE SYSTEMS, WITH TOTAL SNOWFALL
ACCUMULATIONS OF ONLY 1-4" CONFINED TO ELEVATIONS ABOVE 7500 FEET
BY SUNDAY NIGHT. STILL, THERE MAY BE SHORT PERIODS OF SLICK ROADS
AND TRAVEL DELAYS FOR HIGHER SIERRA PASSES THIS WEEKEND WHEN
SNOWFALL RATES INCREASE. ELSEWHERE ACROSS EASTERN CA-WESTERN NV,
ONLY SPARSE LIGHT RAIN FROM TRACE AMOUNTS TO A FEW HUNDREDTHS OF
AN INCH IS EXPECTED OVER THE WEEKEND.
WE'RE STILL ON TRACK FOR A STRONGER STORM LATE MONDAY NIGHT AND
TUESDAY (CHRISTMAS EVE), BRINGING ANOTHER PERIOD OF STRONGER WIND
GUSTS, WITH HEAVIER MOUNTAIN SNOWFALL COMPARED TO THIS WEEKEND.
HOWEVER, RAIN AND SNOW AMOUNTS HAVE TRENDED DOWNWARD IN MORE
RECENT GUIDANCE, WITH A FASTER STORM MOTION LIMITING THE DURATION
OF HEAVIER PRECIP RATES. THERE IS STILL HIGH CONFIDENCE THAT THIS
STORM WILL BRING WINTER TRAVEL IMPACTS LEADING TO TRAVEL DELAYS
LEADING UP TO CHRISTMAS, WITH 50-60% CHANCE FOR AT LEAST 6" OF
SNOWFALL OVER THE MAIN SIERRA PASSES. IN ADDITION, AIR AND LAND
TRAVEL IMPACTS DUE TO WINDS RETURN FOR TUESDAY, SO THE BEST BET
TO MINIMIZE WEATHER-RELATED IMPACTS IS TO TRAVEL ON MONDAY. SNOW
LEVELS COULD FALL TO NEAR 5500 FEET BY EARLY TUESDAY EVENING AS
THE PRECIP WINDS DOWN TO A FEW SHOWER BANDS, LEAVING A SMALL
WINDOW OF OPPORTUNITY FOR A SLIGHTLY WHITE CHRISTMAS FOR HIGHER
FOOTHILL LOCATIONS AROUND RENO-CARSON-MINDEN. HOWEVER, FOR WESTERN
NV/EASTERN CA VALLEYS WE'LL HAVE TO LOOK AT THE MOUNTAINS TO SEE
ANY CHRISTMAS SNOW.
CHRISTMAS DAY IS PROJECTED TO HAVE A BREAK BETWEEN STORM SYSTEMS
WITH DRY CONDITIONS, LIGHT WINDS, AND NEAR-AVERAGE HIGHS OF MID
40S FOR LOWER ELEVATIONS AND NEAR 40 FOR SIERRA COMMUNITIES. THEN
A FEW MORE WAVES OF MOISTURE COULD BRING PERIODS OF INCREASED
WINDS ALONG WITH RAIN AND SNOW. SNOW LEVELS APPEAR TO TREND LOWER
COMPARED TO THE PRE-CHRISTMAS STORMS, SO TRAVEL BETWEEN THE MAIN
HOLIDAYS COULD BE AFFECTED EVEN IN SOME LOWER ELEVATION SITES. MJD
AVIATION
AN APPROACHING STORM WILL BRING PERIODS OF LLWS AND TURBULENCE
LATE TONIGHT AND SATURDAY WITH PEAK FL100/RIDGE TOP GUSTS OF 90+
KT. THE MAIN WIND IMPACTS ARE LIKELY DURING A 3-6 HOUR WINDOW
BETWEEN 16Z-22Z FOR THE TAHOE AREA AND FAR WESTERN NV TERMINALS,
WITH ABOUT 70% CHANCE FOR WIND GUSTS OF 40+ KTS. MOUNTAIN WAVE
TURBULENCE IS LIKELY TO CONTINUE THROUGH THE REMAINDER OF THE
WEEKEND WITH FL100/RIDGE TOP GUSTS AROUND 50-60 KT.
OTHER THAN THE WIND, SHORT PERIODS OF MVFR CIGS/VIS WITH -SHRA
ARE ANTICIPATED FOR KTVL/KTRK SATURDAY LATE MORNING-AFTERNOON
FROM 18Z-00Z, ALONG WITH MOUNTAIN TOP OBSCURATIONS EXTENDING FROM
THE SIERRA INTO FAR WESTERN NV. MJD
REV WATCHES/WARNINGS/ADVISORIES
NV...WIND ADVISORY FROM 4 AM TO 4 PM PST SATURDAY NVZ002-003.
CA...WIND ADVISORY FROM 4 AM TO 4 PM PST SATURDAY CAZ071-072.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page