Heavy Snow in Nevada, January 8, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
356 AM PST TUE JAN 8 2008

.SHORT TERM...
A STRONG SHORTWAVE IS MOVING INTO THE PACIFIC NW ATTM WITH A COLD
FRONT TRAILING SW INTO THE ERN PACIFIC.  THIS COLD FRONT IS ALREADY
BRINGING COASTAL RAIN AND MTN SNOW TO NWRN CALIFORNIA.  SATELLITE
IMAGERY SHOWS THE COLD FRONT STRETCHING FROM NEAR KSEA TO KAST AND
THEN ALONG THE NRN OREGON COAST AND INTO THE PACIFIC.  TRANSVERSE
BANDING IN THE CLOUD SHIELD WITH THE FRONT IMPLY A STRONG ASSOCIATED
UPR LEVEL JET.  THIS 160 KT JET IS HELPING TO PULL THE FRONT QUICKLY
TO THE EAST.  THE JET IS FAIRLY PARALLEL TO THE SRN EXTENT OF THE
COLD FRONT SO THIS PART OF THE FRONT SHOULD NOT MAKE SIGNIFICANT
PROGRESS SOUTH ALONG THE WEST COAST.

HOWEVER THIS COLD FRONT WILL SWING FAR ENOUGH SOUTH TO AFFECT THE
NRN AND CNTRL SIERRA AS IT MOVES THROUGH TODAY.  WILL CONTINUE WITH
WINTER STORM WARNINGS FOR THE NRN SIERRA INCLUDING THE TAHOE BASIN
TODAY.  A SNOW ADVISORY ALSO REMAINS IN EFFECT FOR FAR NWRN NEVADA.
AN IMPRESSIVE SUBTROPICAL MOISTURE TAP IS EVIDENT ON SATELLITE AND
IS DEPICTED IN THE MODELS.  HOWEVER...WITH THE FAST MOVEMENT OF THE
FRONT THROUGH THE REGION...THIS MOISTURE WILL NOT BE AROUND LONG
ENOUGH WITH THIS LATEST SYSTEM TO DEPOSIT EXTREMELY LARGE SNOWFALL
AMOUNTS.  HOWEVER OVER A FOOT OF SNOW IS EXPECTED ABOVE 7000 FEET IN
THE TAHOE BASIN AND UP TO 10 INCHES OF SNOW IS POSSIBLE IN THE
HIGHER ELEVATIONS OF LASSEN COUNTY THROUGH THIS EVENING.

THE COLD FRONT IS PROGGED TO WEAKEN AS IT MOVES INTO THE ERN GREAT
BASIN TONIGHT.  WEAK RIDGING WILL BUILD IN ON WEDNESDAY BEFORE THE
NEXT SYSTEM APPROACHES THE PACIFIC NW.  THE RIDGE IS PROGGED TO
REMAIN IN PLACE AND STEER THE SYSTEM TO OUR NORTH.  THE MAIN
DYNAMICS WILL STAY INVOF THE UPR LOW AS IT MOVES INTO SRN BRITISH
COLUMBIA ON THURSDAY.  HOWEVER THE COLD FRONT ASSOCIATED WITH THIS
SYSTEM WILL MOVE THROUGH THE NRN SIERRA AND NRN NEVADA BRINGING
ANOTHER BOUT OF MTN SNOW AND VALLEY RAIN TO THE KREV CWFA.
TEMPERATURES SHOULD REMAIN NEAR NORMAL THROUGH THE SHORT TERM AS THE
GENERAL WLY FLOW AND CLOUD COVER WILL KEEP WARM AIR ADVECTION AND
INSOLATION RESPECTIVELY AT A MINIMUM.  OHARA

.LONG TERM...FRIDAY THROUGH MONDAY...
MODELS FORECAST LONG WAVE RIDGE TO BUILD ACROSS THE AREA BY THE
WEEKEND. TEMPERATURES ALOFT WILL WARM SIGNIFICANTLY WITH ABOVE
FREEZING TEMPS AT H7 BY SUNDAY. MOUNTAIN TEMPS SHOULD WARM TO ABOVE
NORMAL LEVELS BUT VALLEYS WILL BE A DIFFERENT STORY. AREAS WITHOUT
SNOW COVER WILL WARM TO NEAR NORMAL...BUT THOSE WITH SNOW COVER LOOK
TO REMAIN A FEW DEGREES BELOW NORMAL. ALSO...WITH THE SNOW COVERED
AREAS...FOG IS A CONCERN. MELTING OVER THE NEXT 3 DAYS COULD RESULT
IN FOG FORMATION BY THE WEEKEND AS THE MELTING ADDS SOME MOISTURE TO
THE BOUNDARY LAYER AND SKIES CLEAR. AMOUNT OF FOG WILL DEPEND ON HOW
MUCH SNOW IS LEFT ON GROUND...AS AREAS THAT JUST RECENTLY MELTED ALL
SNOW WILL SEE SOME FOG...BUT THOSE WITH A CONSISTENT COVER WILL BE
MORE WIDESPREAD. WILL JUST HAVE TO WATCH OVER THE NEXT FEW DAYS.
WALLMANN

&&

.AVIATION...
NEXT SYSTEM ALREADY MOVING INTO THE AREA. WILL BE A FAIRLY SHORT
LIVED EVENT WITH CIGS/VIS LOWERING AT KTVL/KTRK THAT WILL START
AROUND 18Z AND LAST INTO 02Z. MVFR CIGS/VIS PROBABLE FOR THESE
LOCATIONS...WITH A 1-2 HOUR PERIOD ALONG THE COLD
FRONT...APPROXIMATELY 23Z WHERE VIS WILL DROP BELOW 1 SM IN MOD/HVY
SNOW.

FOR KRNO...EXPECT SOME WINDS TO INCREASE DURING THE AFTERNOON BUT
STRENGTH IS VERY MUCH UNCERTAIN STILL. IT IS DEPENDENT ON HOW MUCH
WARMING VALLEYS SEE TODAY DUE TO THICKNESS OF CLOUD COVER. GUT
FEELING AT THIS TIME IS WINDS WILL REMAIN ONLY 10KTS OR SO WITH
HIGHER GUSTS WITH A 20 PCT PROBABILITY OF WIND GUSTS OVER 35KTS. A
BRIEF PERIOD OF MVFR CIGS POSSIBLE...60 PCT CHANCE AROUND 23Z AS
FRONT PUSHES THROUGH...AND IT WILL ONLY LAST APPROXIMATELY 1 HOUR.
WALLMANN

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER STORM WARNING FROM 6 AM TO 10 PM PST TODAY FOR NVZ002.

     SNOW ADVISORY FROM 4 AM TO 6 PM PST TODAY FOR NVZ005.

     LAKE WIND ADVISORY FROM 11 AM TO 7 PM PST TODAY FOR NVZ004.

CA...WINTER STORM WARNING FROM 4 AM TO 8 PM PST TODAY FOR CAZ071.

     WINTER STORM WARNING FROM 6 AM TO 10 PM PST TODAY FOR CAZ072.

     SNOW ADVISORY FROM 4 AM TO 6 PM PST TODAY FOR CAZ070.

&&

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