Winter Weather in Nevada, March 15 to 16, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
330 AM PDT SAT MAR 15 2008

.SHORT TERM...
UPPER TROUGH OVER THE WEST COAST CONTINUES TO DEEPEN AND PUSH INTO THE
SOUTHWESTERN STATES. COLD AIR ALOFT ASSOCIATED WITH THE UPPER TROUGH
HAS DESTABILIZED THE ATMOSPHERE OVER CA/NV WITH SCATTERED SHOWERS
CONTINUING OVERNIGHT AND INTO EARLY THIS MORNING ACROSS THE SIERRA
CREST AND INTO THE WESTERN NV VALLEYS. AS THE TROUGH CONTINUES TO
BRING COLD AIR ALOFT...LAPSE RATES WILL STEEPEN TO GREATER THAN 8
DEGREES C/KM ALL THE WAY UP 400 MB...VERY UNSTABLE.

THIS AFTERNOON...SHOWER ACTIVITY WILL INCREASE ACROSS THE ENTIRE
FORECAST AREA...AS ONLY A LITTLE DAYTIME HEATING WILL BE NEEDED TO
INITIATE WIDESPREAD CONVECTIVE SNOW SHOWERS. LIFTED INDICES ARE
EXPECTED TO BE ANYWHERE FROM -1 TO -2...WHICH IS REALLY PRETTY GOOD
FOR OUR AREA THIS TIME OF YEAR. CONTINUED THE MENTION OF SLIGHT
CHANCE OF THUNDERSTORMS...DUE TO THE INSTABILITY IT IS CERTAINLY NOT
OUT OF THE QUESTION. ALSO DUE TO THE CONVECTIVE NATURE...THE
STRONGEST SHOWERS WILL HAVE PEA SIZE HAIL AND SNOW GRAINS MIXED IN.

IN THE SIERRA ZONES...WHERE CONVECTION WILL GET FOCUSED BETTER ALONG
HIGHER TERRAIN...WE CAN EXPECT TO SEE SOME SNOW ACCUMULATIONS...BUT
REMAINING BELOW SNOW ADVISORY CRITERIA. BUT FOR MONO COUNTY...AS THE
COMBINATION OF INSTABILITY AND UPSLOPE FLOW THIS EVENING AND
OVERNIGHT...AS THE SHORTWAVE DROPS INTO SOUTHERN CA...HAS PROMPTED
US TO ISSUE A SNOW ADVISORY FOR THE AREA...ESPECIALLY ALONG AND WEST
OF THE HIGHWAY 395 CORRIDOR IN MONO COUNTY. STORM TOTAL SNOWFALL
ACCUMULATIONS FOR MONO COUNTY WILL VARY GREATLY ACROSS THE
AREA...BUT GENERALLY EXPECTING 3 TO 6 INCHES...WITH 6 TO 12 INCHES
ABOVE 7000 FEET THROUGH SUNDAY MORNING. SEE WSW FOR DETAILS.

STRONG 150 KT NORTHERLY JET MOVING DOWN THE BACKSIDE OF THE UPPER
TROUGH WILL MOVE OVER THE GREAT BASIN ON SUNDAY. THIS WILL MAKE FOR
A BRISK NORTHEAST WIND DAY ACROSS THE REGION. LAKE TAHOE MAY NEED A
LAKE WIND ADVISORY FOR SUNDAY...FOCUSING ON THE WEST SHORES AS THE
EASTERLY WIND SETS UP. AS FOR TEMPS... UNDERCUT MOS QUITE A BIT
UNDER COLD AIR ADVECTION REGIME...BUT MAY STILL BE TOO HIGH. COULD
SEE SOME STRAY LIGHT SNOW SHOWERS CONTINUING IN MONO AND MINERAL
COUNTIES SUNDAY...BUT AS FOR THE REST OF THE AREA PRECIP WILL HAVE
TAPERED OFF BY SATURDAY NIGHT.  RIDGING WILL BUILD BACK INTO THE
REGION MONDAY...WITH TEMPERATURES REBOUNDING BACK TO NEAR SEASONAL
NORMALS.  HOON

.LONG TERM...TUESDAY THROUGH FRIDAY...
FLAT RIDGE OVER AREA AT BEGINNING OF PERIOD WILL LIMIT SHOWERS TO
FAR NORTHERN AREAS WHILE TEMPERATURES RETURN TO ABOVE NORMAL LEVELS.
DAYTIME HIGHS WERE INCREASED A FEW DEGREES TUESDAY AND MORE IN LINE
WITH THE UPPER END OF THE EXTENDED MOS ENSEMBLE DATA. THE REMAINDER
OF THE EXTENDED BECOMES A BIT MORE UNCLEAR AS THE WESTERN U.S. WILL
BE IN BETWEEN ONGOING SYSTEM THAT WILL BE MOVING THROUGH THE CENTRAL
AND EASTERN PART OF THE COUNTRY AND THE NEXT POTENTIAL PATTERN
CHANGE TO EAST PACIFIC TROUGH. SEE CLIMATOLOGY DISCUSSION FROM
FRIDAY AFTERNOON BELOW. ENSEMBLE MEMBERS DIVERGE CONSIDERABLY BEYOND
WEDNESDAY WITH THE ONLY CERTAINTY BEING DEVELOPING TROUGH IN THE
GULF OF ALASKA. MODELS THIS MORNING CONTINUE TO EJECT SHORTWAVE
ENERGY AHEAD OF TROUGH AND INTO THE PACNW. THESE SYSTEMS WILL DAMPEN
AND BRUSH OUR REGION. WHILE THE ECMWF/GFS 24 HOURS AGO WERE IN
DECENT AGREEMENT...THERE ARE DIFFERENCES THIS MORNING AS THE ECMWF
MAINTAINS INITIAL SHORTWAVE WEDNESDAY NIGHT/THURSDAY FOLLOWED BY
SHORTWAVE RIDGE FRIDAY AND SATURDAY. MEANWHILE THE GFS HAS SLOWED
SHORTWAVE AND BRINGS IT THROUGH FRIDAY. THE ECMWF HAS BEEN MOST
CONSISTENT AND HAS SOME AGREEMENT FROM THE DETERMINISTIC CANADIAN
RUN. HOWEVER ENOUGH UNCERTAINTY EXISTS SUCH THAT CHANCES FOR SHOWERS
WERE BROADBRUSHED ACROSS THE NORTHWEST HALF THURSDAY AND FRIDAY.
SLIGHTLY COOLER TEMPERATURES WERE MAINTAINED ALTHOUGH IF INITIAL
SHORTWAVE COMES IN WEAKER PER THE GFS...TEMPERATURES MAY NEED TO BE
RAISED ESPECIALLY WEDNESDAY. NO SIGNIFICANT STORMS ARE ANTICIPATED
DURING THIS PERIOD. HOHMANN
&&

.AVIATION...
SCATTERED TO NUMEROUS SNOW SHOWERS WILL AFFECT AREA TAF SITES. THE
MOST WIDESPREAD COVERAGE OF SHOWERS WILL BE ACCOMPANIED BY ISOLATED
THUNDERSTORMS 20Z-01Z. MVFR/MT OBSCUREMENT WILL BE THE GENERAL RULE
IN SNOW SHOWERS ALTHOUGH HEAVIER SHOWERS ESPECIALLY AT SIERRA TAF
SITES WILL PRODUCE IFR CONDITIONS. SNOW SHOWERS WILL TAPER QUICKLY
AFTER 01Z WITH IMPROVING CONDITIONS OVERNIGHT. SNOW AMOUNTS WILL BE
1 TO 3 INCHES ON SIERRA SITES WITH AN INCH OR LESS AT KRNO/KLOL.
STRONGER CELLS MAY PRODUCE SMALL HAIL WHICH WILL ACCUMULATE BRIEFLY.
WEST WINDS AT RIDGE TOP WILL SHIFT TO THE NORTH THIS AFTERNOON AND
NORTHEAST SUNDAY AND BECOME GUSTY AS UPPER TROUGH SHIFTS SOUTHEAST
OF AREA. HOHMANN
&&

.CLIMATE...   /ISSUED 239 PM PDT FRI MAR 14 2008/

RECENT TRENDS INDICATE THAT THE NEXT PHASE OF THE MJO IS CURRENTLY
PROGRESSING ACROSS THE INDIAN OCEAN.  QUIKSCAT WIND ANALYSIS SHOWS
WESTERLY WINDS FROM 60E TO 90E WITH UNFLAGGED 30 KT VALUES.
ENHANCED CONVECTION IS ALSO OCCURRING WITH A TROPICAL DISTURBANCE
LOCATED WEST OF INDONESIA ALONG THE LEADING EDGE OF THE WESTERLY
WIND ANOMALY.  MJO EVENTS FROM OCT THROUGH EARLY JAN MOVED QUICKLY
INTO THE WESTERN PACIFIC OCEAN WITH A CYCLE OF 40-50 DAYS.  THE MJO
EVENT FROM LATE JAN AND FEB MOVED QUICKLY ACROSS THE INDIAN OCEAN
AND STALLED OVER THE MARITIME CONTINENTAL REGION (INDONESIA AND
NORTH AUSTRALIA).  WITH THE CURRENT STRENGTH OF THE WEST WINDS IN
THE INDIAN OCEAN AND DRY SEASON TRADE WINDS BEGINNING TO DECREASE IN
INTENSITY ACROSS THE WESTERN/CENTRAL PACIFIC IT WILL BE INTERESTING
TO SEE HOW FAST THIS MJO PROGRESSES INTO THE WESTERN PACIFIC OR IF
IT STALLS OVER THE MARITIME CONTINENTAL REGION.

WHAT THIS MEANS FOR OUR AREA...AS WITH PREVIOUS EVENTS THIS
WINTER SEASON...ACTIVE WEATHER ACROSS THE WESTERN US TYPICALLY
FOLLOWS WITHIN A WEEK OF THE MJO MOVING INTO THE WESTERN PACIFIC.
IF THE CURRENT MJO BEHAVES LIKE PAST EVENTS IN DEC AND JAN THE
AREA COULD SEE A CHANGE TO AN ACTIVE WEATHER PATTERN BEGINNING
THE LAST WEEK OF MARCH-FIRST WEEK IN APRIL WITH COOLER
TEMPERATURES AND INCREASED CHANCES FOR PRECIPITATION. MOZLEY

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...SNOW ADVISORY FROM 11 AM THIS MORNING TO 11 PM PDT THIS EVENING
     FOR CAZ073.

&&

HTTP://WEATHER.GOV/RENO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RENO NV
923 AM PDT SAT MAR 15 2008

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

0800 AM     HEAVY SNOW       2 WNW PORTOLA           39.81N 120.50W
03/15/2008  M10.5 INCH       PLUMAS             CA   TRAINED SPOTTER

            10.5 INCHES OF SNOW OVERNIGHT.

0830 AM     HEAVY SNOW       PORTOLA                 39.80N 120.47W
03/15/2008  M10.0 INCH       PLUMAS             CA   CO-OP OBSERVER

            10 INCHES OF SNOW OVERNIGHT. SNOW HAS ENDED WITH CLOUDS
            BREAKING UP.

&&

RC