Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 202332
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
332 PM PST THU NOV 20 2014

.SYNOPSIS...

LOW PRESSURE WILL BRING A QUICK ROUND OF SNOW AND RAIN TO THE SIERRA
AND WESTERN NEVADA THIS EVENING. ANOTHER STORM SYSTEM WILL BRING
STRONGER WINDS SATURDAY, WITH PERIODS OF RAIN AND HIGH ELEVATION
SNOW MAINLY NEAR THE SIERRA CREST AND IN EXTREME NORTHEAST
CALIFORNIA. A DRYING TREND RETURNS EARLY NEXT WEEK AS RIDGE
REBUILDS ALONG THE WEST COAST.

&&

.SHORT TERM...

TODAY`S SYSTEM CONTINUES TO MOVE INTO THE SIERRA THIS AFTERNOON
AND EVENING. IT HAS COME IN A LITTLE WARMER THAN PROJECTED WITH
SNOW LEVELS GENERALLY ABOVE 6500 FEET FOR TONIGHT. STILL, A
QUICK INCH OR SO OF SNOW DOWN TO 6000 FEET WILL BE POSSIBLE AFTER
SUNSET TONIGHT AS THE COLD CORE OF THE LOW MOVES OVER THE SIERRA
IN CONJUNCTION WITH PRECIPITATION LOADING. FORTUNATELY, ROAD
SURFACES WILL MOSTLY BE TOO WARM AROUND THE TRUCKEE AND TAHOE
AREAS FOR WIDESPREAD ICY CONDITIONS. HOWEVER, COOLER ROAD SURFACES
THAT HAVE REMAINED SHADOWED THROUGH THE DAY AND OVERPASSES COULD
BECOME SLICK AS TEMPERATURES DROP OVERNIGHT. EXTRA CARE SHOULD BE
TAKEN IF YOU HAVE PLANS TO BE OUT LATE TONIGHT OR EARLY TOMORROW
MORNING IN THE SIERRA.

OTHERWISE, THE FOCUS FOR WEATHER IMPACTS IS SHIFTING TO SATURDAY`S
SYSTEM. THIS SYSTEM WILL BRING GUSTY WINDS TO THE SIERRA AND,
ESPECIALLY, ALONG THE SIERRA FRONT WHERE WINDS WILL DUCT TO VALLEY
SURFACES. NAM BUFR SOUNDINGS CONTINUE TO SHOW A CRITICAL LAYER
WITH 50 KNOTS DOWN TO 800MB AND NEARLY 60 KNOTS AT 700MB. THIS
CORRELATES TO PAST DOWNSLOPE WIND EVENTS AND SUPPORTS THE
POTENTIAL FOR DAMAGING WIND GUSTS. EVEN WITHOUT THE STABLE LAYER
DUCTING WINDS DOWNSLOPE, WINDS WILL BE GUSTY CONSIDERING THAT WE
SHOULD MIX HIGHER THAN 800MB. THEREFORE, WE HAVE ISSUED A HIGH
WIND WATCH FOR THE SIERRA AND SIERRA FRONT FROM LATE FRIDAY
EVENING TO SATURDAY AFTERNOON. PRECIPITATION IN THE SIERRA WILL
LIKELY DAMPEN THE WIND GUSTS DOWN BELOW WARNING CRITERIA, BUT WILL
KEEP TAHOE IN THE WATCH SINCE 700MB WINDS ARE STRONG. ALSO, ADDED
SOME BLOWING DUST INTO THE FORECAST FOR LOCATIONS EAST OF THE
VIRGINIA RANGE. THIS INCLUDES AREAS DOWNWIND OF THE SMOKE CREEK
DESERT AND THE GREAT BASIN FROM JUST EAST OF PYRAMID LAKE TO
MINERAL COUNTY.

PRECIPITATION IS SOMEWHAT LACKING WITH THE FRIDAY NIGHT/SATURDAY
SYSTEM. PWATS ARE AMPLE IN THE 1" TO 1.5" RANGE, BUT FORCING IS
SEVERELY DISPLACED INTO THE PACIFIC NORTHWEST. WHAT PRECIPITATION
DOES SQUEEZE OUT WILL BE DUE TO A PASSING WEAK UPPER LEVEL
TROUGH, SOME OROGRAPHIC UPSLOPING, AND SOME WARM AIR ADVECTION.
THESE MECHANICS DO NOT FAVOR LARGE PRECIPITATION TOTALS FOR SHORT
DURATIONS LIKE THE TIMESCALE OF THIS SYSTEM. STILL, A FEW INCHES
OF HIGHER ELEVATION SNOW WILL BE POSSIBLE MAINLY ABOVE 8000 FEET
WITH UP TO 6 INCHES ALONG THE CREST ITSELF. MODELS ARE HANDLING
SNOW LEVELS VERY POORLY AND THE VARIABILITY IS QUITE LARGE; SOME
DOWN TO 5000 FEET WITH OTHERS AROUND 10000 FEET. HOPEFULLY, THERE
WILL BE A BETTER CONSENSUS IN FOLLOWING RUNS SO THAT WE CAN NAIL
DOWN TOTALS MORE FIRMLY. ELSEWHERE, PRECIPITATION WILL BE MUCH
MORE ANEMIC DUE TO A PRONOUNCED RAIN SHADOW WITH MAINLY TOKEN
AMOUNTS EAST OF HIGHWAY 395. BOYD

.LONG TERM...SUNDAY THROUGH THANKSGIVING DAY...

DRY CONDITIONS WILL PREVAIL FOR SUNDAY AND INTO EARLY NEXT WEEK AS
AN UPPER LEVEL RIDGE BECOMES ESTABLISHED ACROSS THE EASTERN PACIFIC.
SEASONABLE TEMPERATURES WILL PREVAIL INTO EARLY NEXT WEEK WITH LOW
TO MID 50S FORECASTED AREA WIDE BY MONDAY AFTERNOON AS THE RIDGE
SLOWLY BUILDS ALONG THE WEST COAST. CONFIDENCE IS GOOD IN
ESTABLISHING THIS RIDGE ACROSS THE WEST COAST INTO TUESDAY BUT
RAPIDLY DETERIORATES BY WEDNESDAY AND INTO THANKSGIVING DAY.

THE MAIN FOCUS IN THE EXTENDED FORECAST WILL BE GAUGING ANY TRAVEL
IMPACTS NEAR THE THANKSGIVING HOLIDAY AS SOME MODELS HAVE SHOWN A
POTENTIAL FOR A COLD FRONT TO BRING RAIN AND SNOW ACROSS WESTERN
NEVADA DURING THE WEDNESDAY AFTERNOON AND EVENING TIME FRAME. THE GFS
CONTINUES TO SHOW A WARM/DRY PATTERN DURING THIS PERIOD WHILE THE EC
HAS BEEN COOLER/WETTER AS IT BRINGS IN THIS FRONTAL SYSTEM. THE
LAST THREE RUNS OF THE EC HAVE TRENDED DRIER AND MORE IN LINE WITH
THE GFS WITH ONLY VERY LIGHT PRECIP SCRAPING FAR EASTERN PERSHING
AND CHURCHILL COUNTIES. HAVE TRENDED THE FORECAST SLIGHTLY DRIER BUT
IT IS IMPORTANT TO NOTE THAT UNCERTAINTY IS HIGH AND CONFIDENCE IN
MODELS MAINTAINING THIS DRY SOLUTION IS LOW MAINLY DUE TO THE VERY
HIGH SPREADS SHOWN IN BOTH THE NAEFS AND EC. THOSE WITH TRAVEL PLANS
AROUND THE THANKSGIVING HOLIDAY SHOULD CONTINUE TO MONITOR THE
FORECAST WHICH WILL BE REFINED OVER THE NEXT SEVERAL DAYS. FUENTES

&&

.AVIATION...

A LOW PRESSURE SYSTEM WILL INCREASE SHOWERS ACROSS THE SIERRA
TERMINALS THIS EVENING. A MIX OF RAIN AND SNOW SHOWERS WILL
TRANSITION TO LIGHT SNOW SHOWERS ACROSS KTRK/KTVL/KMMH AFTER 00Z AS
SNOW LEVELS DROP AROUND 6,000 FT MSL. MVFR CONDITIONS WITH BRIEF IFR
CONDITIONS POSSIBLE FOR KTRK/KTVL WITH THE BEST POTENTIAL THRU 04Z
WITH SHOWERS DIMINISHING AFTER 04Z AND ENDING AROUND 08Z. UP TO AN
INCH OF SNOW ACCUMULATION IS POSSIBLE AT KTRK/KTVL. MOUNTAIN TOP
OBSCURATION IS EXPECTED MAINLY FOR SIERRA RIDGES WITH PERIODS OF
MVFR CONDITIONS FOR KMMH THROUGH AROUND 06Z. ONLY BRIEF MVFR
CONDITIONS AND LIGHT RAINFALL EXPECTED ACROSS KRNO/KCXP.

BIGGEST IMPACTS TO AVIATION LOOK TO BE AFTER 00Z SATURDAY, WHEN
THE JET PUSHES INTO NORTHERN CALIFORNIA. HIGH CONFIDENCE EXISTS
FOR A MODERATE TO STRONG WIND EVENT ACROSS AND EAST OF THE SIERRA
AND A HIGH WIND WATCH HAS BEEN ISSUED. MOUNTAIN WAVES AND
TURBULENCE WILL START AFTER 00Z SATURDAY WITH POTENTIAL FOR GUSTS
OF 40-60 KTS GUSTS IN THE LOWER ELEVATIONS 06Z-21Z SATURDAY. THE
SATURDAY SYSTEM WILL ALSO BRING A PERIOD OF RAIN AND SNOW TO THE
SIERRA WHICH COULD LEAD TO MVFR/IFR CONDITIONS AT KTVL-KTRK.
FUENTES/BRONG

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...HIGH WIND WATCH FROM FRIDAY EVENING THROUGH SATURDAY AFTERNOON
     NVZ002-003.

CA...HIGH WIND WATCH FROM FRIDAY EVENING THROUGH SATURDAY AFTERNOON
     CAZ071>073.

&&

$$

FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)







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