Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 221128
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
328 AM PST SAT NOV 22 2014

.SYNOPSIS...
A STORM SYSTEM WILL BRING STRONG WINDS WITH PERIODS OF RAIN AND
HIGH ELEVATION SNOW TODAY, ESPECIALLY NEAR THE SIERRA CREST AND
THE OREGON BORDER. CONDITIONS BECOME COOLER AND DRIER ON SUNDAY
FOLLOWED BY A SLOW WARMING TREND NEXT WEEK AS HIGH PRESSURE BUILDS
OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA.

&&

.SHORT TERM...
LOOKING AT TEMPERATURE/DEWPOINT OBSERVATIONS IN EASTERN CALIFORNIA
FROM LASSEN COUNTY SOUTH TO ALPINE COUNTY, SNOW LEVELS ARE RUNNING
BETWEEN 7000-7500 FEET AND 8500 FEET. SO FAR THIS MORNING, THERE
ARE NO CHAIN OR SNOW TIRE REQUIREMENTS IN THE NORTHERN SIERRA
(JUST WET ROADS) WITH ROAD TEMPERATURES IN THE MID TO UPPER 30S
BELOW 8500 FEET. WIND-WISE, WINDS HAVE PICKED UP SOMEWHAT UP IN
THE SURPRISE VALLEY WITH GUSTS 35-50 MPH. THIS IS LIKELY AIDED BY
A STRONGER PRESSURE GRADIENT THERE CLOSER TO A SURFACE LOW OVER
OREGON. ELSEWHERE, HIGHER WINDS ALOFT HAVE BEEN SLOW TO MIX DOWN
INTO THE VALLEYS WITH A MOIST AND FAIRLY STABLE BOUNDARY LAYER.

THIS MORNING, A COLD FRONT WILL PUSH THROUGH NORTHEAST CALIFORNIA
AND NORTHWEST NEVADA. GIVEN THAT IT IS ALREADY RAINING AHEAD OF
THE FRONT NORTH OF PORTOLA AND GERLACH, I DO NOT EXPECTED WINDS TO
MAKE IT TO HIGH WIND CRITERIA (SUSTAINED 40 WITH GUSTS 58+). THE
FRONT WILL BE THROUGH MUCH OF NORTHEAST CALIFORNIA AND NORTHWEST
NEVADA BEFORE NOON, SO I SUSPECT THE ONLY CHANCE FOR HIGH WINDS
FOR LASSEN AND EASTERN PLUMAS/SIERRA COUNTIES WILL BE ALONG
HIGHWAY 395 SOUTH OF JANESVILLE AND PERHAPS IN THE EASTERN SIERRA
VALLEY THIS MORNING...AND THAT CHANCE IS WANING AS PRECIPITATION
CONTINUES TO SPILLOVER AND DAMPEN POTENTIAL MOUNTAIN WAVES.

FARTHER SOUTH IN THE LEE OF THE SIERRA (ESPECIALLY ALONG AND WEST
OF HIGHWAY 395), THERE IS STILL A FAIR CHANCE AT A PERIOD OF HIGH
WINDS INTO EARLY AFTERNOON AS THE FRONT APPROACHES. IN FACT, WINDS
IN THE FOOTHILLS SOUTHWEST OF RENO (AND SPORADICALLY AT THE RENO
AIRPORT) HAVE BACKED TO SOUTH-SOUTHEAST WHICH MAY INDICATE THE
POTENTIAL FOR MOUNTAIN/DOWNSLOPE WAVE DEVELOPMENT.

PRECIP-WISE TODAY, DEEP MOISTURE WITH A RESIDUAL PWAT TAP OF
1.2-1.5 INCHES OVER NORTHERN CALIFORNIA COULD AID THE OCCASIONAL
SPILLOVER OF LIGHT PRECIPITATION NORTH OF HIGHWAY 50 ALTHOUGH THE
MOST SIGNIFICANT PRECIP WILL REMAIN IN THE SIERRA. IN THE SIERRA,
SNOW LEVELS REMAIN HIGH AHEAD OF THE FRONT SO IMPACTS TO PASSES
LOOK TO BE MAINLY ABOVE 8000 FEET. ALSO, PRECIPITATION SHOULD BE
TAPERING OFF BY THE TIME SNOW LEVELS REALLY COME DOWN THIS
AFTERNOON.

TONIGHT THROUGH MONDAY, THE WEATHER QUIETS DOWN AS A RIDGE OF HIGH
PRESSURE SLOWLY BUILDS OVERHEAD. TEMPERATURES WILL START OUT SLIGHTLY
BELOW AVERAGE SUNDAY BEFORE SLOWLY REBOUNDING EARLY NEXT WEEK.
SNYDER

.LONG TERM...TUESDAY THROUGH FRIDAY...
MODELS AND THEIR ENSEMBLES CONTINUE TO POINT TO STRONG RIDGE TUE-WED
WITH GFS 500MB HEIGHT ANOMALIES ON THE ORDER OF +15 DAM. THE GFS AND
ECMWF DO SHOW A LOT OF HIGH CLOUDS MAKING IT THROUGH THE RIDGE, SO
TEMPERATURES MAY HAVE A HARD TIME GETTING AS HIGH AS SOME OF THE MOS
GUIDANCE, ESPECIALLY GIVEN THE LIGHT BOUNDARY LAYER WINDS. BY
THU-FRI, UPPER RIDGE WILL BEGIN TO MOVE EAST AND WEAKEN AS ENERGY
ADVANCES EASTWARD IN THE PACIFIC. THERE IS A LOT OF UNCERTAINTY
STILL WITH A POTENTIAL TROUGH PASSAGE NEXT WEEKEND ALTHOUGH THE
ENSEMBLE MEMBERS DO SHOW SLIGHTLY NEGATIVE HEIGHT ANOMALIES BY
SAT-SUN OVER NV. AT THE SAME TIME, THE GFS HAS TRENDED WEAKER WITH
THAT SYSTEM. THE ECMWF IS FLATTER AND MORE PROGRESSIVE. A SLIGHT
CHANCE OF SHOWERS WAS MAINTAINED NORTHERN SIERRA AND FAR NORTHWEST
NV FRI-SAT. FOR TRAVEL PURPOSES, CONFIDENCE IS HIGH THAT THERE WILL
BE NO IMPACT FOR WEDNESDAY AND THANKSGIVING DAY. CONFIDENCE DROPS TO
LOW FOR THE WEEKEND AS THERE IS AT LEAST A POTENTIAL FOR SNOW IN THE
HIGHER ELEVATIONS. WE ARE TRYING TO ANTICIPATE SOME WARMING OF
VALLEYS AHEAD OF THIS FEATURE THU-FRI AND HAVE WARMED TEMPS UP A
NOTCH BOTH DAYS. HOHMANN

&&

.AVIATION...
UPPER JET ACROSS NORTHERN CA AND NORTHWEST NV WILL COMBINE WITH
STRONG SURFACE PRESSURE GRADIENT TO BRING GUSTY WINDS TO MUCH OF THE
AREA TODAY WITH LEE SIDE TURBULENCE LIKELY. RIDGE WINDS WILL GUST AS
HIGH AS 90KT WITH PERIODS OF STRONG WIND GUSTS 40-60KT ALONG THE
HIGHWAY 395 CORRIDOR. STRONGEST AND MOST WIDESPREAD WINDS WILL BE IN
THE 15Z-21Z WINDOW, BUT MAY LINGER A BIT LONGER OVER MONO COUNTY AS
FRONT PUSHES THROUGH THAT AREA THIS AFTERNOON. WE HAVE MAINTAINED
LOW LEVEL WIND SHEAR AT TAHOE AND SIERRA FRONT AIRPORTS WHERE
DIRECTIONAL SHEAR WILL BE POSSIBLE AHEAD OF FRONT. OUT IN THE BASIN
AND RANGE, BLOWING DUST WILL REDUCE VISIBILITY TO AROUND ONE MILE AT
TIMES.

MOUNTAIN OBSCURATION AND BRIEF PERIODS MVFR CONDITIONS ARE EXPECTED
IN RAIN SHOWERS NEAR KTRK/KTVL WITH A CHANGE OVER TO SNOWFALL BY
SUNDOWN AS PRECIPITATION BEGINS TO WANE. LITTLE IN THE WAY OF SNOW
ACCUMULATION EXPECTED. HOHMANN

&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...HIGH WIND WARNING UNTIL 4 PM PST THIS AFTERNOON NVZ003.

     WIND ADVISORY UNTIL 4 PM PST THIS AFTERNOON NVZ002-005.

     WIND ADVISORY UNTIL 7 PM PST THIS EVENING NVZ001-004.

CA...HIGH WIND WARNING UNTIL 4 PM PST THIS AFTERNOON CAZ071.

     WIND ADVISORY UNTIL 4 PM PST THIS AFTERNOON CAZ070-072.

     HIGH WIND WARNING UNTIL 7 PM PST THIS EVENING CAZ073.

&&

$$

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







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