High Wind in Nevada, February 6, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
335 AM PST FRI FEB 6 2015

.SYNOPSIS...
A STRONG PACIFIC STORM WILL AFFECT THE REGION OVER THE NEXT COUPLE
DAYS WITH VERY STRONG WINDS TODAY. RAIN WILL BEGIN THIS MORNING OVER
NORTHEAST CALIFORNIA WITH A PERIOD OF HEAVY RAIN AND HIGH ELEVATION
SNOW ALONG THE SIERRA CREST INTO SATURDAY MORNING. AFTER A BRIEF
BREAK SUNDAY ANOTHER STORM IS LIKELY SUNDAY AND MONDAY WITH ADDITIONAL
RAIN AND HIGH ELEVATION SNOW.

&&

.SHORT TERM...

A WARM PACIFIC WINTER STORM AND ASSOCIATED ATMOSPHERIC RIVER (AR)
CONTINUES TO PUSH ACROSS NORTHERN CALIFORNIA. THE PRIMARY IMPACT
WILL BE POWERFUL AND POTENTIALLY DAMAGING DOWNSLOPE WINDS
DEVELOPING TODAY. THIS STORM WILL ALSO PROVIDE PERIODS OF HEAVY RAIN
AND HIGH ELEVATION SNOWFALL ACROSS THE SIERRA AND NORTHEASTERN
CALIFORNIA THROUGH SATURDAY WITH LIGHTER RAINFALL ACCUMULATIONS
ACROSS WESTERN NEVADA. ANOTHER ROUND OF HEAVY PRECIPITATION WITH A
BETTER SPILLOVER POTENTIAL IS POSSIBLE BY SUNDAY AFTERNOON INTO
MONDAY AS A SECONDARY STORM SYSTEM SENDS AN ADDITIONAL MOISTURE
PLUME ACROSS THE REGION.

***POWERFUL DOWNSLOPE WINDS TODAY***

CURRENT WIND OBSERVATIONS, SATELLITE PRESENTATION, AND LATEST
NUMERICAL GUIDANCE CONTINUE TO SHOW THE INGREDIENTS FOR A STRONG
DOWNSLOPE WINDSTORM TO DEVELOP TODAY ACROSS AND LEEWARD OF THE
SIERRA WITH THE POTENTIAL FOR DAMAGING WIND GUSTS. SEEING STRONG
GUSTS ACROSS LASSEN COUNTY THROUGH THE TAHOE BASIN WITH 50-60+ MPH
WINDS ALREADY BEING REPORTED. A WIND GUST OVER 72 MPH WAS RECORDED
AT THE NWS OFFICE IN NORTH RENO TONIGHT WITH PERSISTENT GUSTS BETWEEN
40-50 MPH. GUSTS ACROSS SQUAW PEAK AND SLIDE MOUNTAIN HAVE PEAKED AT
116 MPH AND 111 MPH RESPECTIVELY THUS FAR.

THESE WINDS WILL CONTINUE TO INCREASE TODAY AS 700MB WINDS (~10,000')
INCREASE TO A HOWLING 70-75KTS. A HIGH WIND WARNING IS IN EFFECT
EARLY THIS MORNING THROUGH TONIGHT AS DOWNSLOPE WINDS DEVELOP. THE
PEAK OF THE WINDS LOOK TO OCCUR BY LATE MORNING THROUGH EARLY
EVENING WHERE THERE IS THE BEST POTENTIAL TO DEVELOP A VERTICALLY
PROPAGATING AND BREAKING WAVE ACROSS THE SIERRA. VERY STRONG AND
DAMAGING WIND GUSTS UP TO 60-70 MPH WITH POTENTIAL FOR LOCALIZED
GUSTS 80+ MPH ARE POSSIBLE IN WIND PRONE AREAS ALONG HIGHWAY 395.

POTENTIAL IMPACTS INCLUDE: DANGEROUS CROSS-WINDS FOR MOTORISTS ON
ROADWAYS, AIRPORT DELAYS/CANCELLATIONS, POWER OUTAGES, LOW
VISIBILITY IN AREAS OF BLOWING DUST, AND DANGEROUS CONDITIONS ON
AREA LAKES WITH WAVE HEIGHTS UP TO 7' POSSIBLE ON LAKE TAHOE'S
NORTHEASTERN SHORES.

AS FOR THE BASIN AND RANGE IN PERSHING,CHURCHILL,MINERAL,SOUTHERN
LYON COUNTIES, THE WINDS WILL BE LESS AROUND 45-55 MPH. A BLOWING
DUST ADVISORY HAS BEEN ISSUED FOR THESE AREAS DUE TO THE IMPACTS OF
BLOWING DUST ON THE CARSON AND HUMBOLDT SINKS FROM THE PROLONGED DRY
PERIOD. STRONG WINDS WILL CREATE LOW VISIBILITY CONDITIONS ON
HIGHWAY 50, 95, AND INTERSTATE 80 EAST OF RENO/CARSON CITY.

***PRECIPITATION/SNOW LEVEL TODAY AND TONIGHT***

RADAR MOSAIC SHOWING A LARGE SWATH OF PRECIPITATION SPREADING ACROSS
MUCH OF NORTHERN CALIFORNIA. THIS WILL CONTINUE TO PUSH ACROSS
LASSEN AND PLUMAS COUNTY THIS MORNING WITH THE SOUTHERN FRINGE
PUSHING INTO THE TAHOE BASIN BY MID AFTERNOON, THEN INTO MONO COUNTY
BY EARLY EVENING. NO APPRECIABLE CHANGE IN THE FORECAST WITH THIS
SYSTEM. SNOW LEVELS WILL REMAIN HIGH WITH FLUCTUATIONS MAINLY
BETWEEN 7500-8500 FEET.

FRIDAY NIGHT INTO SATURDAY MORNING WILL BE THE TIMEFRAME WHERE THE
BULK OF THE PRECIPITATION WILL OCCUR. THROUGH SATURDAY MORNING
RAINFALL ACCUMULATIONS OF 1.5-3.0" IS POSSIBLE WITH A RATHER SHARP
GRADIENT INTO WESTERN NEVADA AS SPILLOVER IS ON THE WEAKER SIDE.
AMOUNTS IN THE 0.25"-0.50" ARE POSSIBLE ALONG THE HIGHWAY 395
CORRIDOR WITH A FEW HUNDREDTHS FURTHER EAST ACROSS THE BASIN AND
RANGE.

HEAVY SNOWFALL WILL BE CONFINED TO THE HIGHER ELEVATIONS MAINLY
ABOVE 8,500 FEET WHERE A FOOT OR TWO OF HEAVY WET SNOW(~8:1 RATIO)
IS POSSIBLE ACROSS THE SIERRA. IMPACTS TO SIERRA HIGHWAYS WILL BE
LOCALIZED TO THE HIGHEST PASSES INCLUDING MOUNT ROSE SUMMIT AND
CARSON PASS. IF SNOW LEVELS DROP BY ABOUT 500 FEET, DONNER SUMMIT
AND ECHO SUMMIT MAY BE IMPACTED BY A FEW INCHES OF HEAVY WET SLUSH
AS WELL. OPTED TO NOT ISSUE A WINTER WEATHER ADVISORY FOR THE TAHOE
BASIN WITH THE LIMITED IMPACTS FOR AREAS ABOVE 8,500' BUT DID ISSUE
ONE FOR MONO COUNTY WHERE GREATER COVERAGE OF TERRAIN ABOVE 8,500'
EXISTS. ADVISORY COVERS AREAS ABOVE 8,000' BUT MOST PROBABLE AREAS
FOR SNOWFALL ACCUMULATION WILL BE ABOVE 8,500' WHERE 8-16" OF SIERRA
CEMENT IS POSSIBLE WITH LOCALLY UP TO 18-24" IS POSSIBLE ALONG THE
CREST PARTICULARLY OVER NORTHERN MONO COUNTY.

***SUNDAY AND MONDAY SYSTEM***
A SECONDARY SYSTEM WILL PROVIDE ANOTHER SHOT AT SIGNIFICANT RAINFALL
AND HIGH ELEVATION SNOWFALL SUNDAY INTO MONDAY. THIS WILL ALSO BE A
WARM SYSTEM WITH SNOW LEVELS GENERALLY NEAR 8,500 FEET THROUGH EARLY
MONDAY MORNING AHEAD OF A SURFACE COLD FRONT. THIS SYSTEM WILL
PRESENT A BETTER SPILLOVER POTENTIAL FOR WESTERN NEVADA AS BETTER
DYNAMICS AND JET ORIENTATION ACCOMPANY THE MOISTURE. MODELS HAVE
TRENDED WETTER AND HAVE INCREASED POPS/QPF ACROSS ALL AREAS. ANOTHER
2+ INCHES OF LIQUID ACCUMULATIONS IS POSSIBLE ALONG THE SIERRA CREST
WITH UP TO 0.5" THROUGH THE SIERRA FRONT AND 0.25" ACROSS THE BASIN
AND RANGE. IF THE CURRENT DYNAMIC FORCING, INSTABILITY, AND MOISTURE
PLUME HOLD WE COULD SEE THESE VALUES COME UP QUITE A BIT FOR WESTERN
NEVADA IN THIS MUCH MORE FAVORABLE SPILLOVER SET UP. CONFIDENCE IS
MEDIUM IN QPF VALUES AS SOME MODELS ARE QUITE A BIT DRIER (NAM) IN
COMPARISON TO THE GFS AND EC.

THIS ADDITIONAL PRECIPITATION SHOULD HAVE AN IMPACT ON LOCAL STREAM
FLOWS WHICH WILL RESPOND MORE QUICKLY THAN FRIDAY AND SATURDAY. THIS
RESPONSE COULD BRIEFLY PUSH A FEW STREAMS OVER THEIR BANKS. NO
FLOODING OF MAINSTEM RIVERS IS EXPECTED. SEE HYDROLOGY SECTION FOR
ADDITIONAL DETAILS.  FUENTES

LONG TERM...MONDAY THROUGH THURSDAY...
THE SECOND STRONG SYSTEM WILL BE EXITING MONDAY, BUT SOME SHOWERS
WILL CONTINUE DURING THE DAY. THE MOST NUMEROUS SHOWERS WILL BE IN
THE MORNING AND IN THE SIERRA WITH SOME LIGHT ADDITIONAL SNOW
ACCUMULATIONS POSSIBLE THERE AS SNOW LEVELS LOWER TO 5000 FEET. IN
WESTERN NEVADA, SCATTERED SHOWERS WILL BECOME MORE ISOLATED WITH NO
ACCUMULATION EXPECTED. TEMPERATURES WILL BE MUCH COLDER WITH HIGHS
CLOSER TO AVERAGE FOR MID FEBRUARY, BUT A BRISK WEST WIND WILL MAKE
IT FEEL COLDER ESPECIALLY AFTER THE RECENT RECORD BREAKING TEMPS.

TUESDAY, THE PART OF THE SYSTEM WILL SPLIT OFF AND SAG SOUTH THROUGH
EASTERN NEVADA AND EVENTUALLY END UP OVER SOUTHERN CALIFORNIA BY
WEDNESDAY. THIS WILL BRING A NORTHEAST FLOW TO THE SIERRA AND
WESTERN NEVADA BOTH DAYS. TEMPERATURES WILL BE SLOW TO WARM UP, WITH
ANOTHER SEASONABLE DAY TUESDAY BEFORE TEMPS START TO WARM WEDNESDAY.
THE FLOW WILL WEAKEN THURSDAY WITH SOME MORE WARMING TO A FEW
DEGREES ABOVE AVERAGE. INVERSIONS WILL FORM, BUT THEY WILL BE WEAKER
THAN SEEN LAST MONTH WITH A STRONGER FEB SUN. OVERNIGHT LOWS WILL
ALSO BE SEASONABLY COLD UNDER CLEAR SKIES. WALLMANN

&&

.AVIATION...
STRONG WINDS CONTINUE TO BE THE CONCERN FOR THE NEXT 24 HOURS WITH A
STRONG MTN WAVE DEVELOPING OVER THE SIERRA AT THE MOMENT. MTN WAVE
TURBULENCE AND ASSOCIATED LLWS DUE TO TERRAIN CHANNELING ARE
EXPECTED FOR THE NEXT 18 HOURS THRU 06Z TONIGHT. THE WORST
CONDITIONS FOR WINDS FOR TERMINALS AROUND RENO-TAHOE WILL BE FROM
18-00Z TODAY. MODELS ARE SHOWING A BREAKING WAVE SIGNATURE WITH THE
STRONGEST WIND SHEAR AND TURBULENCE LIKELY THEN WITH WIND GUSTS TO
50-55KTS POSSIBLE AT KCXP/KTVL/KRNO. THIS WILL BE DELAYED BY ABOUT
3-6 HOURS FOR KMMH. THE WINDS WILL WEAKEN AFTER 06Z AS MORE PRECIP
MOVES OVER THE SIERRA, BUT THERE WILL STILL BE SIGNIFICANT
TURBULENCE AND WIND GUSTS TO 35 KTS AT THE TERMINALS. HIGH
CONFIDENCE OF 80-90 PCT WITH THIS WIND EVENT.

OTHER CONCERN WILL BE MVFR/IFR CONDS IN RAIN. THIS WILL SPREAD OVER
KSVE AROUND 20Z TODAY AND SLOWLY SAG SOUTH THIS AFTERNOON AND
TONIGHT OVERTAKING KTVL/KTRK BY 00Z AND KRNO BY 04Z. MTN OBSCN
LIKELY ALSO WITH VIS DOWN TO 2SM AT TIMES IN +RA IN THE SIERRA.
IMPROVING CONDS AFT 12Z WITH MORE SHOWERY CONDITIONS EXPECTED
SATURDAY. CONFIDENCE HIGH NEAR 80 PCT.

A BIT OF A BREAK SAT AFTERNOON/EVENING WITH MORE SCT/ISOLD MVFR
CIGS/VIS IN THE SIERRA. THEN THE NEXT STORM IS EXPECTED SUNDAY INTO
SUNDAY NIGHT WITH MORE RAIN/SNOW. WINDS DO NOT APPEAR TO BE AS MUCH
OF AN ISSUE WITH THIS ONE. HOWEVER, THERE REMAINS A 20 PCT CHANCE OF
SEEING A STRONG WIND EVENT AGAIN AS ONE MODEL AND A FEW ENSEMBLES
ARE SHOWING THIS POSSIBILITY. WALLMANN

&&

.HYDROLOGY...
LATEST MODEL GUIDANCE CONTINUES THE TREND OF BRINGING PERIODS OF
HEAVY PCPN INTO NORTHERN CA STARTING FRIDAY THEN SLIDING THIS
HEAVIER PCPN DOWN THE SPINE OF THE SIERRA THROUGH SATURDAY
EVENING. HIGH SNOW LEVELS WILL PROMOTE MORE RAIN THAN SNOW IN THIS
SYSTEM AND THE PERIODS OF HEAVIEST PCPN COULD PRODUCE ENOUGH HEAVY
RAIN TO INCREASE RUN OFF AND ELEVATE SMALL STREAMS...ESPECIALLY
FROM THE CARSON RIVER BASIN NORTH INTO NORTHEAST CA. THERE ARE
SOME THINGS THAT MAY LIMIT STREAM RISES...CHIEF AMONG THESE ARE
DRY SOILS AND ANTECEDENT VERY LOW FLOWS. STILL...WITH UPWARDS OF
2 TO 4 INCHES OF LIQUID POSSIBLE IN THE SIERRA AND CENTRAL PLUMAS
AND WESTERN LASSEN COUNTIES...SOME NEAR BANKFULL FLOWS ARE LIKELY
ON THE SMALLER STREAMS WITH ELEVATED FLOWS ON THE MAIN RIVERS.

WHILE NO SIGNIFICANT FLOODING CONCERNS EXIST AT THIS TIME...IT
WILL BE IMPORTANT FOR ANYONE NEAR SMALL STREAMS FROM MARKLEEVILLE
NORTH THROUGH THE TAHOE BASIN AND INTO NORTHEAST CA TO BE ALERT TO
THE POSSIBILITY OF RISING WATERS FROM LATE FRIDAY NIGHT THROUGH
SATURDAY.

THE SECOND SYSTEM SUNDAY NIGHT INTO MONDAY...WHILE LESS POTENT...
WILL BE MOVING ACROSS ALREADY SATURATED SOILS AND COULD CAUSE
MORE RAPID RISES EVEN WITH LESS RAINFALL.

WHILE WE DO NOT PLAN ANY FLOOD WATCHES AT THIS TIME...WE WILL BE
CAREFULLY MONITORING THE SITUATION AS THE RAIN STARTS FRIDAY AND
BECOMES HEAVY FRIDAY NIGHT INTO SATURDAY MORNING. 20

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...HIGH WIND WARNING UNTIL 4 AM PST SATURDAY NVZ002-003-005.

     WIND ADVISORY UNTIL 4 AM PST EARLY THIS MORNING NVZ002-003-005.

     BLOWING DUST ADVISORY UNTIL 4 AM PST SATURDAY NVZ001-004.

     LAKE WIND ADVISORY UNTIL 4 AM PST EARLY THIS MORNING FOR PYRAMID
     LAKE IN NVZ004.

CA...HIGH WIND WARNING UNTIL 4 AM PST SATURDAY CAZ070>073.

     WIND ADVISORY UNTIL 4 AM PST EARLY THIS MORNING CAZ070>073.

     WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM PST
     SATURDAY ABOVE 8000 FEET FOR CAZ073.

&&

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