Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 241016
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
316 AM PDT FRI OCT 24 2014

.SYNOPSIS...
AFTER A WARM AND SUNNY AFTERNOON TODAY, LOW PRESSURE OFF THE WEST
COAST WILL MOVE INLAND ON SATURDAY, BRINGING A PERIOD OF STRONG
GUSTY WINDS ALONG WITH LIGHT RAIN AND MOUNTAIN SNOW. COOLER
CONDITIONS WITH LINGERING SHOWERS ARE EXPECTED SUNDAY, WITH MILD
AND DRIER CONDITIONS MONDAY THROUGH THURSDAY.

&&

.SHORT TERM...
LITTLE CHANGE TO THE SHORT TERM FORECAST. AN OFFSHORE TROUGH
DIGGING ALONG 130W WILL CREATE A WARM AND BREEZY AFTERNOON ACROSS
WESTERN NV AND THE SIERRA TODAY. BREEZY SOUTHWEST WINDS WILL
COMBINE WITH LOW HUMIDITY FOR A MODERATE FIRE THREAT ACROSS
WESTERN NV THIS AFTERNOON. RIDGE LEVEL WINDS WILL STRENGTHEN
MARKEDLY TODAY AND THIS EVENING, AND WITH GUSTS UP TO 40 MPH AT
LAKE TAHOE A LAKE WIND ADVISORY IS IN EFFECT STARTING LATE THIS
EVENING.

AS THE TROUGH MOVES ONSHORE, WINDS AT RIDGE LEVEL CONTINUE TO
STRENGTHEN TONIGHT AND SATURDAY MORNING. THERE MAY BE SOME
ISOLATED DOWNSLOPE GUSTS ALONG THE FRONT RANGE SATURDAY MORNING,
BUT THIS POTENTIAL IS LIMITED BECAUSE RIDGE LEVEL WINDS ARE
SOUTH- SOUTHWEST AND NOT DIRECTLY CROSS-BARRIER. NONETHELESS,
VERY WINDY CONDITIONS ARE EXPECTED SATURDAY WHILE A COLD FRONT
CROSSES THE SIERRA AND WESTERN NV. A WIND ADVISORY REMAINS IN
EFFECT FOR SATURDAY INCLUDING THE HIGHWAY 395 CORRIDOR FROM LASSEN
SOUTHWARD TO MONO COUNTY AND ALSO FOR NORTHWEST NV, FOR GUSTS UP
TO 55 MPH. STRONGER GUSTS UP TO 70 MPH ARE FORECAST FOR WIND PRONE
LOCATIONS. ALTHOUGH WIND GUSTS ARE LESS LIKELY TO REACH ADVISORY
CRITERIA IN WEST CENTRAL NV, AREAS OF BLOWING DUST WILL BE
POSSIBLE SATURDAY AFTERNOON AND EVENING. DRY CONDITIONS AHEAD OF
THE COLD FRONT COULD ALSO CREATE CRITICAL FIRE WEATHER CONDITIONS
SATURDAY FOR PORTIONS OF WESTERN NV, SEE THE FIRE WEATHER SECTION
BELOW FOR ADDITIONAL DISCUSSION.

RAIN IS LIKELY SATURDAY AFTERNOON THROUGH EVENING FROM THE TAHOE
BASIN NORTHWARD. STORM TOTALS BY SUNDAY MORNING OF AROUND 0.20
INCHES ARE EXPECTED AT SOUTH LAKE TAHOE, AND 0.25-0.50 INCHES ARE
POSSIBLE FARTHER NORTH FOR NORTHEAST CA INCLUDING PLUMAS AND
LASSEN COUNTIES, AND FOR THE SURPRISE VALLEY AND NORTHERN WASHOE
COUNTY. SNOW LEVELS ABOVE 9000 FEET SATURDAY WILL LOWER TO
7000-7500 FEET BY SUNDAY MORNING. HOWEVER, BY THE TIME SNOW
LEVELS DROP BELOW 8000 FEET SATURDAY NIGHT, MOST OF THE
PRECIPITATION WILL HAVE DIMINISHED. AN INCH OR TWO OF SNOW MAY
ACCUMULATE ON HIGHER PEAKS SATURDAY NIGHT BUT ARE UNLIKELY TO
SIGNIFICANTLY IMPACT MOUNTAIN PASSES. JCM/MJD

.LONG TERM...MONDAY THROUGH THURSDAY...
I MADE FEW CHANGES TO THE LONG TERM FORECAST ESPECIALLY GIVEN THE
UNCERTAINTY MID-LATE WEEK. EARLY ON, THE MODELS ARE IN AGREEMENT
WITH THE JET REMAINING IN THE PACIFIC NORTHWEST WITH THE WEAKENING
FRONT DRAGGING ACROSS SOMETIME WEDNESDAY, WITH A SLIGHT CHANCE OF
SHOWERS NORTH OF I-80. TEMPERATURES WILL GRADUALLY WARM BACK ABOVE
NORMAL FOR MIDWEEK AFTER A COOL DAY MONDAY.

LATE WEEK, THE MODELS DIVERGE SIGNIFICANTLY. THE GFS IS MORE
PROGRESSIVE, WINDIER AND WETTER ESPECIALLY BY FRIDAY WITH THE NEXT
SYSTEM. THE EC CUTS THE NEXT SYSTEM OFF THE COAST WITH A STRONG
RIDGE OVER THE GREAT BASIN. THESE RUNS HAVE FLIP FLOPPED WITH EACH
OTHER THE PAST 36 HOURS WHEN THE GFS WAS RIDGY AND THE EC SHOWED THE
TROUGH. I BELIEVE THE EC ENSEMBLE MEAN IS PROBABLY THE WAY TO GO. IT
SHOWS A LOT OF UNCERTAINTY, BUT IT IS ALSO MORE PROGRESSIVE THAN THE
EC BUT A LITTLE SLOWER THAN THE GFS. THE FORECAST REMAINS LOW
CONFIDENCE, BUT RETAINED THE SLIGHT CHANCE/LOW CHANCE OF PRECIP
FORECAST FOR LATE WEEK. IF ANYTHING, I BELIEVE WE MAY BE UNDERDOING
IT JUST A BIT AS WE GET TO FRIDAY. LEFT TEMPS MILD AS WINDS AND
MIXING WILL OFFSET ANY COOLING ALOFT AT LEAST INITIALLY. WALLMANN

&&

.AVIATION...
EXPECT GENERAL VFR CONDITIONS NEXT 24 HOURS WITH SOME LOCALLY BREEZY
CONDITIONS AS WINDS GUST TO 25 KTS NEAR THE SIERRA. ANY LOCAL MVFR
CONDITIONS OVER WESTERN LASSEN COUNTY WILL DISSIPATE THIS MORNING AS
THE JET LIFTS NORTH.

SATURDAY, THE MAIN SYSTEM MOVES IN WITH INCREASING WINDS ALOFT.
WINDS WILL BE LOCALLY BREEZY AFTER 06Z TONIGHT WITH SOME MTN WAVE
TURBULENCE. AFTER 12Z SAT, THE WINDS INCREASE WITH TURBULENCE AND
LLWS LIKELY WHERE WINDS ARE CHANNELED BY STRONG WINDS ALOFT. IN
GENERAL, EXPECT SW WINDS OF 25-30 KT AT THE TERMINALS WITH GUSTS
40-45 KTS AFT 15Z POSSIBLY LASTING THROUGH 00Z SUN.

AS THE COLD FRONT NEARS, EXPECT SOME MVFR/IFR CONDITIONS IN -RA WITH
MTN OBSCN. THIS WILL BEGIN OVER WESTERN LASSEN BY 18Z AND SLOWLY SAG
SOUTHEAST TO I-80 BY 00Z. THE BIGGEST THREAT WILL REMAIN IN THE
SIERRA. WALLMANN

&&

.FIRE WEATHER...
WINDS WILL INCREASE TODAY WITH GUSTS 25-30 MPH WITH RH AROUND
10-15%. THE BIGGER CONCERN WILL BE SATURDAY AS STRONG WINDS ARE
EXPECTED THROUGHOUT THE AREA AHEAD OF A STRONG COLD FRONT. THE FRONT
IS EXPECTED TO MOVE INTO LASSEN COUNTY AROUND 18Z AND THROUGH THE
I-80 CORRIDOR NEAR 00Z AND MONO/MINERAL COUNTIES BY 04Z.

WINDS AHEAD OF THE FRONT WILL GUST TO 55 MPH AND LOCALLY HIGHER
IN WIND PRONE AREAS. THE AREA OF BIGGEST CONCERN WILL BE SOUTH OF
I-80 IN WESTERN NEVADA. RH WILL BE INCREASING SIGNIFICANTLY OVER
TODAY NORTH OF I-80 SO IT IS LESS OF A CONCERN THERE. WITH AREAS
SOUTH OF I-80 REMAINING AHEAD OF THE FRONT LONGEST, RH LOOKS TO
DROP TO 15-25%. COMBINED WITH THESE STRONG WINDS, CRITICAL
CONDITIONS ARE POSSIBLE. WINDS ALSO LOOK TO GUST ALONG THE HIGHWAY
95 CORRIDOR AS THE PEAK OF THE WINDS AND THE FRONTAL TIMING IS
IDEAL FROM A CLIMATOLOGICAL PERSPECTIVE. WILL HOIST A FIRE WEATHER
WATCH FROM 8 AM TO 8 PM SATURDAY FOR NV ZONES 450, 453 AND 459. I
BELIEVE 453/459 STAND THE BEST CHANCE SINCE THEY WILL BE AHEAD OF
THE FRONT LONGER, BUT 450 COULD HIT FOR A WHILE LATE MORNING/EARLY
AFTERNOON. WALLMANN

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...WIND ADVISORY FROM 8 AM TO 11 PM PDT SATURDAY NVZ003-005.

     LAKE WIND ADVISORY FROM 11 PM THIS EVENING TO 11 PM PDT SATURDAY
     FOR LAKE TAHOE IN NVZ002.

     FIRE WEATHER WATCH FROM SATURDAY MORNING THROUGH SATURDAY
     EVENING NVZ450-453-459.

     LAKE WIND ADVISORY FROM 11 AM TO 11 PM PDT SATURDAY FOR PYRAMID
     LAKE IN NVZ004.

CA...WIND ADVISORY FROM 8 AM TO 11 PM PDT SATURDAY CAZ070-071.

     WIND ADVISORY FROM 11 AM TO 11 PM PDT SATURDAY CAZ073.

     LAKE WIND ADVISORY FROM 11 PM THIS EVENING TO 11 PM PDT SATURDAY
     FOR LAKE TAHOE IN CAZ072.

&&

$$

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








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