Wildfire and High Wind in Nevada, November 18 to 19, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
855 PM PST THU NOV 17 2011

.UPDATE...
WINDS INCREASING OVER THE SIERRA AND WESTERN NEVADA THIS EVENING
AS THE COLD LOW DROPS SOUTH ALONG THE PACIFIC NORTHWEST COAST.
GUSTS ARE APPROACHING 60 MPH IN THE WIND PRONE AREAS ALONG HIGHWAY
395 IN WESTERN NEVADA WITH SIERRA RIDGES GUSTING AT 70 TO 90 MPH.
UPSLOPE FLOW INTO THE NORTHERN SIERRA IS GENERATING LIGHT
RAIN/SNOW OVER THE CREST AND INTO THE TAHOE BASIN, WITH SNOW
LEVELS 7000-7500 FEET. CLOUD TOP TEMPERATURE NEAR -8C, SHOW A
LIMITED DEPTH TO THE SHOWERS. ACCUMULATIONS TONIGHT SHOULD REMAIN
BELOW AN INCH.

LATEST MODEL RUNS ARE SLOWER WITH FRONT REACHING INTERSTATE 80 AND
RENO-TAHOE UNTIL LATE FRIDAY AFTERNOON. THE SLOWER FRONTAL TIMING
WOULD ALLOW A STRONGER THERMAL GRADIENT TO DEVELOP OVER WESTERN
NEVADA, AND SUSTAIN A LONGER DURATION DOWNSLOPE WIND EVENT ALONG
HIGHWAY 395 FROM RENO TO MAMMOTH. THIS WOULD ALSO PRODUCE STRONGER
WINDS ALONG HIGHWAY 95 THROUGH PERSHING, CHURCHILL AND MINERAL
COUNTIES.

SECOND IMPACT IS A SLOWER TIMING OF THE BAND OF SNOW ALONG THE
FRONT, WITH A DRY SLOT WORKING INTO THE NORTHERN SIERRA FRIDAY
AFTERNOON. WAVE ROUNDING THE BASE OF THE TROUGH WILL PASS FROM
LASSEN COUNTY TO CHURCHILL COUNTY FRIDAY EVENING. PLACING THE BEST
LIFT, INSTABILITY AND MOISTURE DEPTH OVER AREAS NORTH OF
SUSANVILLE TO LOVELOCK. MOISTURE DEPTH OVER THE TAHOE BASIN IS
LIMITED, THUS POTENTIAL FOR MODERATE SNOW IS DECREASING. CURRENT
FORECAST FOR 2-5 INCHES AND 4-8 ALONG THE SIERRA CREST COULD BE
OVERDONE. BRONG

&&

.AVIATION...

AT KRNO: INCREASING WINDS AND TURBULENT FLOW DOWNWIND OF THE SIERRA
ARE CREATING ERRATIC WINDS AT THE TERMINAL. WILL INTRODUCE LOW
LEVEL WIND SHEAR TO THE FORECAST WITH WINDS AT THE NWS OFFICE, 500
FEET ABOVE THE TERMINAL AT 24030G45KT. UPDATED THE FORECASTS FOR
KTVL AND KTRK EARLIER THIS EVENING FOR LOW LEVEL WIND SHEAR,
WHICH SHOULD CONTINUE THROUGH 12-14Z.

STRONGEST WINDS MAY BE DELAYED UNTIL MID MORNING FRIDAY, AND BAND OF
SNOW MAY NOT MOVE THROUGH RENO-TAHOE UNTIL 00Z SATURDAY DUE TO
SLOWER SOUTHWARD PROGRESSION OF THE FRONT.

FORECAST FOR PEAK WINDS IS UNCHANGED...WITH 40-45KT GUSTS POSSIBLE
AT KTVL AND KTRK AND 40-50KT GUSTS FOR KRNO AND KMMH.

&&

.PREVIOUS DISCUSSION... /ISSUED 243 PM PST THU NOV 17 2011/

SHORT TERM...
UPPER LEVEL TROUGH WAS MOVING INTO THE PACNW WITH COLD AIR CUMULUS
NOTED OVER THE PACIFIC JUST OFF THE OR-NORTHERN CA COAST. COLD
FRONT IS WORKING SOUTHEASTWARD ACROSS NORTHERN CA AND OR AND
WILL SAG INTO FAR NORTHERN ZONES TONIGHT AND THEN SLOW TO A CRAWL
AS IT AWAITS MAIN UPPER JET ON FRIDAY. OVERALL...MODELS HAVE
SLOWED JUST A BIT WITH THE SOUTHWARD FRONTAL PUSH WHICH WOULD
BRING IT TO NEAR KRNO-KLOL BY LATE AFTERNOON AND THEN OUT OF THE
AREA MID-LATE EVENING. STRONG SURFACE GRADIENT...APPROACHING JET AND
RIDGE LEVEL WINDS WILL RESULT IN WINDY CONDITIONS ACROSS ALL
AREAS PRIOR TO FRONTAL PASSAGE. THE 12Z GFS SHOWED SOME REVERSAL
IN WINDS ABOVE STABLE LAYER AT BRIDGEPORT WHICH SUGGESTS THERE
STILL IS POTENTIAL FOR BREAKING WAVES AND AT LEAST A 1-2 HOUR
PERIOD OF HIGH WINDS ALONG HIGHWAY 395 FROM RENO TO MAMMOTH LAKES
FRIDAY. WINDS ALONG THE EASTERN SIERRA WILL BE CLOSE TO ADVISORY
LEVELS EARLY THIS EVENING IN WIND PRONE AREAS BUT WILL LEAVE HIGH
WIND WARNING START TIME AS IS AND MENTION LOCALLY HIGHER GUSTS
UNTIL THEN.

THE GFS/NAM CAME IN A BIT LESS AMPLIFIED WITH UPPER LEVEL
FRONT WITH BEST JUXTAPOSITION OF MOISTURE...FRONTAL LIFT AND
INSTABILITY NORTH OF I-80 FRI AFTERNOON AND EVENING. SNOW LEVELS
SHOULD FALL TO MOST VALLEY FLOORS BY THE ONSET OF HEAVIEST
PRECIPITATION. INTENSITY OF SNOW SHOULD BE BEST FRIDAY AFTERNOON
AND EARLY EVENING WHICH SHOULD OFFSET AFTERNOON SUN AND ALLOW FOR
ACCUMULATION. WINTER WEATHER ADVISORY WILL BE ISSUED FOR TRAVEL
IMPACTS DUE TO SNOW FOR THESE AREAS WITH SNOW DEVELOPING FIRST IN
THE SURPRISE VALLEY AND WESTERN LASSEN COUNTY AND THEN WORKING
SOUTHWARD INTO THE EARLY EVENING. UPPER JET AND EASTWARD
PROGRESSION OF TROUGH/UPPER FRONT WILL RESULT IN FRONTAL
ACCELERATION AND DRYING IN MID LEVELS. FORCING AND MOISTURE ALONG
AND JUST BEHIND FRONT WILL STILL BE SUFFICIENT FOR HEAVY SNOW
SHOWERS. HOWEVER FASTER FRONTAL MOVEMENT WILL LIMIT HEAVY SNOW
SHOWERS TO A 1-2 HOUR PERIOD FOR POINTS SOUTH OF I-80. RIGHT NOW
CONFIDENCE IN TIMING IS ONLY MEDIUM. IF BAND HOLDS TOGETHER WELL
AND COMES IN AT PROJECTED TIME (NEAR OR RIGHT AFTER SUNSET)...THEN
SOME LIGHT ACCUMULATIONS (UP TO AN INCH) COULD IMPACT THE FRIDAY
EVENING RENO-CARSON RUSH HOUR. IN ADDITION...WHILE THERE IS NO
WINTER WEATHER ADVISORY FOR THE TAHOE BASIN...SOME SNOW
ACCUMULATION IS EXPECTED. GUSTY WINDS AND BLOWING SNOW WILL RESULT
IN SOME TRAVEL DELAYS THROUGH THE SIERRA PASSES FRIDAY AFTERNOON
AND EVENING.

TEMPERATURES WERE WARMED A BIT IN AREAS SOUTH OF I-80 ON FRIDAY TO
ACCOUNT FOR SLOWER FRONTAL ARRIVAL WITH WINDS EXPECTED TO KEEP
LOWS UP TONIGHT IN MOST AREAS. OTHERWISE MUCH COLDER CONDITIONS
WILL FOLLOW THE FRONT INTO FRIDAY NIGHT AND SATURDAY WITH HARD
FREEZES RETURNING TO ALL AREAS. AFFECTS OF SYSTEM WORKING
SOUTHWARD THROUGH THE EASTERN PACIFIC WILL REMAIN MOSTLY WEST OF
AREA THIS WEEKEND WITH THE ECMWF RUN ON THE EAST SIDE OF THE MODEL
ENVELOPE AND THUS SHOWING THE BEST POTENTIAL FOR SOME PRECIPITATION
TO REACH THE SIERRA. DID NOT MAKE ANY CHANGES TO FORECAST WHICH
INDICATES A SLIGHT CHANCE OF SHOWERS. HOHMANN

LONG TERM...
GOOD MID TERM MODEL AGREEMENT THAT A SHORT WAVE RIDGE WILL BUILD IN
MONDAY WHICH WILL INTRODUCE A WARMING TREND FOR THE BEGINNING OF
NEXT WEEK. WARMER TEMPERATURES WITH LIGHT WINDS WILL CONTINUE
THROUGH TUESDAY WITH PARTLY CLOUDY CONDITIONS. ANOTHER LOW PRESSURE
SYSTEM WILL DEVELOP IN THE GULF OF AK AND BEGIN TO PUSH OVER THE
EASTERN PACIFIC TUESDAY AND WILL LIKELY IMPACT THE AREA FOR THE
THANKSGIVING HOLIDAY.

TIMING OF THE NEXT TROUGH SYSTEM IS THE MAIN CONCERN AS MODELS ARE
HANDLING THE OVERALL SYNOPTIC PATTERN QUITE WELL FOR MID TO LATE
NEXT WEEK. A DEEP LOW PRESSURE SYSTEM...DRIVEN BY A 150+ KT JET
STREAK IN THE EASTERN PACIFIC...IS PROGGED TO DIP SOUTH ALONG THE
WEST COAST AND THEN PUSH EAST. MAIN IMPACTS WILL BE GUSTY WINDS
AHEAD OF A COLD FRONT COUPLED WITH GOOD MID LEVEL MOISTURE WHICH HAS
POTENTIAL FOR MODERATE PRECIP AMOUNTS. DUE TO THE RIDGING AHEAD OF
THE SYSTEM...THE STORM WILL INITIALLY BE WARMER WITH HIGHER SNOW
LEVELS BEFORE THE COLD FRONT PASSES THROUGH.

THE GFS AND ECMWF ENSEMBLE MEANS AND OPERATIONAL MODEL SOLUTIONS
SHOW THE AXIS OF THE TROUGH BEGINNING TO MOVE EAST INTO NORTHER CA
LATE WEDNESDAY INTO THURSDAY...WITH PRECIPITATION BEGINNING THURSDAY
MORNING IN THE NORTHERN SIERRA. THE GEM REMAINS AN OUTLIER WITH IT'S
FASTER TIMING AND WETTER SOLUTION...WITH PRECIP BEGINNING WEDNESDAY
IN THE NORTHERN SIERRA AND PROGRESSING SOUTHEAST INTO WESTERN NV BY
WEDNESDAY NIGHT. ALL SOLUTIONS SHOW A PERIOD OF GUSTY SOUTHWEST
WINDS AHEAD OF WARMER PRECIP ONSET WITH INITIALLY HIGHER SNOW LEVELS
ALONG THE ASSOCIATED COLD FRONT. TEMPERATURES WILL LIKELY COOL BELOW
NORMAL BEHIND THE FRONT. HAVE GONE WITH A COMPROMISE OF THE ECMWF
AND GFS SOLUTIONS AS GEM SEEMS TO BE TOO MUCH OF AN OUTLIER WITH
LITTLE ENSEMBLE SUPPORT AT THIS TIME. THIS SYSTEM HAS THE POTENTIAL
TO CAUSE TRAVEL PROBLEMS IN THE SIERRA BEFORE AND DURING THE
THANKSGIVING HOLIDAY. THOSE WITH TRAVEL PLANS SHOULD CONTINUE TO
MONITOR THIS SITUATION AS THE DETAILS DEVELOP OVER THE NEXT FEW
DAYS. LABELLE

AVIATION...
GUSTY WINDS WILL CONTINUE AT ALL TERMINALS AND WILL INCREASE THIS
EVENING...WITH GUSTS BETWEEN 40-45 KTS EXPECTED BY 12Z AT
KRNO...KTRK AND KTVL. PEAK GUSTS OF 45-50 KTS WILL OCCUR AT KMMH
AFTER 15Z AND LAST INTO THE AFTERNOON. SIERRA RIDGE WINDS WILL
CONTINUE TO GUST 65-75 KTS THIS EVENING AND INCREASE TO 80-100 KTS
EARLY FRI WITH TURBULENCE LIKELY ALONG AND DOWNSTREAM OF THE
MOUNTAINS. WINDS WILL DISSIPATE FRI EVENING.

MID LEVEL MOISTURE WILL MOVE IN WITH THE SYSTEM WHICH WILL LEAD TO
AN INCREASE IN CLOUD COVER WITH CHANCE FOR PRECIPITATION IN THE
SIERRA. SNOW WILL DEVELOP IN THE SIERRA FROM TAHOE NORTH 12Z-18Z WITH
THE MAIN FRONT APPROACHING TAHOE-RENO AREA BY 19/00Z. KMMH WILL SEE
LIMITED SNOWFALL FROM THIS SYSTEM AS THE FRONTAL PRECIPITATION WILL
LIKELY DISSIPATE AS IT CONTINUES SOUTH FRIDAY EVENING. WHILE RUNWAY
ACCUMULATIONS WILL BE LIMITED TO A COUPLE INCHES AT KTVL/KTRK...CIGS
AND VSBYS COULD DROP FOR A PERIOD OF TIME IN SNOW SHOWERS OR AS
THE SNOW RATE INCREASES ALONG AND BEHIND THE FRONT FOR AIRPORTS
ALONG AND NORTH OF HIGHWAY 50. LABELLE

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY FROM 10 AM TO 10 PM PST FRIDAY NVZ005.

     WIND ADVISORY UNTIL 10 AM PST FRIDAY NVZ005.

     WIND ADVISORY UNTIL 4 PM PST FRIDAY NVZ002.

     BLOWING DUST ADVISORY FROM 4 AM TO 4 PM PST FRIDAY NVZ001-004.

     HIGH WIND WARNING UNTIL 1 PM PST FRIDAY NVZ003.

CA...WINTER WEATHER ADVISORY FROM 10 AM TO 10 PM PST FRIDAY
     CAZ070-071.

     WIND ADVISORY UNTIL 10 AM PST FRIDAY CAZ070-071.

     HIGH WIND WARNING FROM 1 AM TO 4 PM PST FRIDAY CAZ073.

     WIND ADVISORY UNTIL 4 PM PST FRIDAY CAZ072.

&&

HTTP://WEATHER.GOV/RENO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RENO NV
1043 PM PST THU NOV 17 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0950 PM     NON-TSTM WND GST 4 NE MOUNT ROSE SKI ARE 39.38N 119.83W
11/17/2011  M58.00 MPH       WASHOE             NV   MESONET

            MEASURED IN GALENA AT BASE OF MT ROSE HIGHWAY.

0954 PM     NON-TSTM WND GST 5 SE MOUNT ROSE SKI ARE 39.27N 119.82W
11/17/2011  M71.00 MPH       WASHOE             NV   MESONET

            MEASURED AT NDOT SITE IN WASHOE VALLEY.

1026 PM     NON-TSTM WND GST 5 WSW GARDNERVILLE      38.91N 119.83W
11/17/2011  M61.00 MPH       DOUGLAS            NV   TRAINED SPOTTER

&&

BRONG