Lake Wind Advisory 2, NWS Reno, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
220 PM PST TUE JAN 28 2014

.SYNOPSIS...
A STRONG STORM IS EXPECTED WEDNESDAY NIGHT AND THURSDAY WITH
RAIN AND MOUNTAIN SNOW. SNOW LEVELS WILL START HIGH, BUT LOWER TO
ALL VALLEY FLOORS BY FRIDAY MORNING. HEAVY SNOW AMOUNTS ARE
POSSIBLE IN THE HIGHER ELEVATIONS WITH SIGNIFICANT RAINFALL INTO
WESTERN NEVADA. THE STORM WILL PULL EAST ON FRIDAY WITH COOLER
TEMPERATURES EXPECTED INTO THE WEEKEND.

&&

.SHORT TERM...
MAIN ISSUE CONTINUES TO BE THE SIGNIFICANT WINTER STORM FORECAST
FOR WEDNESDAY NIGHT AND THURSDAY. CHANGES INVOLVED INCREASING THE
QPF AMOUNTS AND ALSO LOWERING SNOW LEVELS AS MODELS TREND A LITTLE
FARTHER SOUTH AND COOLER. UNTIL THE STORM HITS, EXPECT ABUNDANT
MID AND HIGH CLOUD COVER THROUGH WEDNESDAY MORNING WITH PERHAPS A
SHOWER OR TWO NEAR THE OREGON BORDER. TEMPS WILL REMAIN MILD
OVERNIGHT WITH THE CLOUD COVER.

BY WEDNESDAY AFTERNOON, THE DEEP MOISTURE PLUME ARRIVES INTO
NORTHEAST CA/NORTHWEST NV AND RIDES ALONG THE POLAR FRONT THAT
SLOWLY MOVES SOUTH. PRECIP WILL INCREASE FROM NORTH TO SOUTH
WEDNESDAY NIGHT AND COULD BECOME HEAVY AT TIMES THURSDAY MORNING.
HOWEVER, THERE ARE DIFFERENCES IN THE MODELS THAT DEAL WITH
TIMING. THE GFS AND ESPECIALLY THE NAM ARE FASTER WITH MOVING THE
PLUME THROUGH BY 18Z THURSDAY. THE EC IS SLOWER AND SHOWS A MORE
PHASED SOLUTION WITH INTENSE FORCING DURING THE DAY THURSDAY. THE
EC IS A WETTER/STRONGER SOLUTION, BUT EVEN THE GFS IS QUITE WET
ALTHOUGH A BIT WARMER. OF NOTE IS THAT THE EC SHOWS A CLASSIC
TONOPAH LOW PATTERN WITH A STRONG SURFACE LOW DEVELOPING NEAR
TONOPAH THURSDAY. IF THIS OCCURS, IT WILL RESULT IN LOWER SNOW
LEVELS DUE TO THE STRONG NORTH SFC PRESSURE/ISALLOBARIC GRADIENT.
HAVE GONE WITH A BLEND, AND WHILE THE TIMING IS MORE TOWARDS THE
SLOWER EC IN THE FORECAST, THE QPF/SNOW TOTALS ARE MORE OF A BLEND.

LOOKING AT TOTAL QPF AMOUNTS OF AROUND 2.5 INCHES FOR THE CREST
AROUND TAHOE AND 1-1.5 INCHES FOR THE BASIN NORTH TO WESTERN
LASSEN COUNTY AND INTO MONO COUNTY. FOR WESTERN NEVADA, 1/2 TO 1
INCH OF RAIN FOR THE SIERRA FRONT AND CLOSER TO 1/3 TO 1/2 INCH
ELSEWHERE. SNOW LEVELS START NEAR 8000 FEET TOMORROW AFTERNOON
THEN GRADUALLY FALL TO LAKE LEVEL BY THURSDAY MORNING AND ALL
VALLEY FLOORS THURSDAY NIGHT. THERE IS STILL A LOT OF UNCERTAINTY
WITH HOW FAST THEY FALL FOR THE LAKE SO SNOW AMOUNTS AT LAKE LEVEL
ARE STILL VAGUE. EXPECT CLOSE TO 2 FEET ALONG THE CREST ABOVE 8000
FEET WITH A FOOT OR MORE DOWN TO 7000 FEET. RIGHT NOW IT LOOKS TO
BE 4-8 INCHES AT LAKE LEVEL AND DOWN TO 5500 FEET IN LASSEN COUNTY
WITH THE BLEND. THE COLDER, STRONGER EC COULD PUT AMOUNTS CLOSER
TO A FOOT. HOPEFULLY THE NEXT COUPLE RUNS SORT THIS OUT. IN THE
MEANTIME, ADDED LASSEN/PLUMAS AND MONO TO THE WINTER STORM WATCH.
LOOKS LIKE IT COULD BE MORE ADVISORY, BUT IF SNOW LEVELS LOWER
FASTER WARNING AMOUNTS REMAIN POSSIBLE. WALLMANN

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
JET AND FRONTAL DYNAMICS WANE THURSDAY NIGHT ACROSS THE SIERRA
AND WESTERN NEVADA ALTHOUGH BAND OF RAIN/SNOW WILL BE ONGOING
THURSDAY EVENING, ESPECIALLY SOUTH OF I-80. SNOW LEVELS SHOULD BE
FALLING TO MOST VALLEY FLOORS WITH SOME ACCUMULATING SNOW POSSIBLE
DOWN TO ABOUT 5000 FEET WITH A CHANGE OVER OR MIX ALL THE WAY DOWN
TO 4000 FEET BEFORE PRECIPITATION TAPERS OVERNIGHT. A COUPLE OF
INCHES OF SNOW ARE POSSIBLE ABOVE 5000 FEET WITH AN INCH POSSIBLE
PRIMARILY ON GRASSY SURFACES AT THE VALLEY FLOORS OF WESTERN NV.
HIGHER UP IN THE SIERRA, ALL PRECIPITATION WILL HAVE CHANGED OVER
WITH ACCUMULATING SNOW PERSISTING AS THE EVENT WINDS DOWN. MOST OF
THE ACCUMULATING SNOW WILL OCCUR THURSDAY EVENING ALLOWING FOR
ROADS TO BE TREATED OVERNIGHT IN ADVANCE OF THE FRIDAY MORNING
COMMUTE. HOWEVER, WHERE LEFT UNTREATED, ESPECIALLY SECONDARY ROADS
ABOVE 5000 FEET, ROAD SURFACES WILL LIKELY BE SLICK AND HAZARDOUS.

OTHERWISE, SNOW SHOWERS WILL BE TAPERING FRIDAY WITH THE BIGGEST
IMPACT BEING THE MUCH COLDER TEMPERATURES. AFTER THE MILD WEATHER,
TEMPERATURES MAY STRUGGLE TO HIT 40 DEGREES THROUGH SATURDAY.
LOWERED HIGHS A COUPLE OF DEGREES, TOWARDS THE ECMWF, WHICH MAY BE
THE BEST SOLUTION FOR AREAS THAT RECEIVE SNOWFALL.  HOHMANN

A SHORTWAVE MOVING SOUTHEASTWARD FROM THE GULF OF ALASKA IS EXPECTED
TO REACH THE CALIFORNIA COAST SUNDAY. THIS WILL MAINTAIN LOW
PRESSURE ALOFT OVER CA/NV BUT ENERGY/MOISTURE LOOKS TO BE TOO FAR
WEST TO BRING SIGNIFICANT PRECIPITATION TO THE SIERRA OR WESTERN NV.
MODELS DIFFER ON THE AMOUNT OF COOLING ALOFT WITH THIS FEATURE BUT
THERE COULD BE ENOUGH INSTABILITY FOR LIGHT SNOW SHOWERS OVER THE
SIERRA SUN-MON. THIS SHORTWAVE IS EXPECTED TO CONTINUE SOUTHEASTWARD
WHICH WOULD BRING A DRY NORTHWEST FLOW OVER THE SIERRA AND WESTERN
NV FOR TUESDAY. JCM

.AVIATION...
CLOUDS AND PRECIPITATION WILL SPREAD SOUTH OUT OF OREGON TONIGHT
WITH CLOUD BASES DOWN TO 3500 FEET AGL AS FAR SOUTH AS KTRK AND
KTVL BY 12Z. EXPECT PERIODS OF MODERATE TO HEAVY PRECIPITATION
WEDNESDAY THROUGH THURSDAY WITH POTENTIAL FOR IFR CONDITIONS
ACROSS THE SIERRA AND WESTERN NV. GUSTY RIDGETOP WINDS UP TO 50
KTS WILL DEVELOP ACROSS NE CA AND NW NV WEDNESDAY MORNING AND THEN
SPREAD SOUTH OVER THE SIERRA CONTINUING THROUGH THURSDAY. JCM

.REV WATCHES/WARNINGS/ADVISORIES...
NV...LAKE WIND ADVISORY FROM 3 AM TO 10 PM PST WEDNESDAY FOR LAKE
     TAHOE IN NVZ002.

     WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH LATE THURSDAY
     NIGHT NVZ002.

CA...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
     EVENING ABOVE 5000 FEET FOR CAZ071.

     WINTER STORM WATCH FROM LATE WEDNESDAY NIGHT THROUGH LATE
     THURSDAY NIGHT ABOVE 7000 FEET FOR CAZ073.

     LAKE WIND ADVISORY FROM 3 AM TO 10 PM PST WEDNESDAY FOR LAKE
     TAHOE IN CAZ072.

     WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH LATE THURSDAY
     NIGHT CAZ072.

&&

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