Snow Advisory 2, NWS Reno, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
358 AM PST FRI JAN 13 2006

.SHORT TERM...
COLD AND VIGOROUS STORM SYSTEM BETWEEN 130 AND 140W LONGITUDE
CONTINUES TO MARCH EASTWARD THIS MORNING. VERY COLD AIR BEHIND THE
SYSTEMS COLD FRONT (FEW HUNDRED MILES WEST OF THE NORTHERN
CALIFORNIA COAST) IS EVIDENCED BY LOADS OF COLD AIR CUMULUS
DEVELOPMENT IN THE INFRARED SATELLITE ALL THE WAY SOUTH TO 30N
LATITUDE. A SECONDARY SHOT OF EVEN COLDER AIR ALOFT IS DIVING SOUTH
FROM THE GULF OF ALASKA AT ABOUT 45N/140W.

MODEL PROGS STILL BRING THE COLD FRONT INTO THE SIERRA AND WESTERN
NEVADA LATE FRIDAY AND SATURDAY MORNING. THE GFS HAS BEEN VERY
CONSISTENT IN THE LAST FEW RUNS...WITH EVEN THE SOMETIMES SQUIRRELLY
06Z RUN PLAYING BALL. TODAY WILL BE A VERY PLEASANT DAY AHEAD OF THE
COLD FRONT...WITH BREEZY AFTERNOON CONDITIONS AND TEMPERATURES NEAR
60 DEGREES FOR THE LOWER VALLEYS. MID LEVEL CLOUDS THIS MORNING ARE
BEGINNING TO DISSIPATE IN COVERAGE AS MODEST OVERRUNNING PUSHES INTO
NORTHERN NEVADA. THEREFORE...I EXPECT PARTLY CLOUDY SKIES TO
ACCOMPANY THE MILD TEMPERATURES THIS AFTERNOON.

TONIGHT AND SATURDAY...THE COLD FRONT MOVES THROUGH CALIFORNIA INTO
CENTRAL NEVADA. AHEAD OF THE FRONT FOR THE SIERRA...OROGRAPHIC FLOW
IS NOT IDEAL WITH MORE SOUTH THAN SOUTHWEST WINDS AT 700-500 MB.
HOWEVER...BEHIND THE FRONT THE FLOW GOES MORE SOUTHWEST TO WEST AND
THE ATMOSPHERE GETS VERY UNSTABLE FOR WINTER WITH AROUND 0C LIS AND
35-38 MODIFIED TOTAL TOTALS PROGGED BY THE GFS. THIS SHOULD KEEP
PRECIP GOING THROUGH SATURDAY...FOR QUITE A BIT OF POST-FRONTAL
SIERRA SNOWFALL. QPF PROGS ARE FOR ABOUT 1.5 INCHES OF LIQUID PRECIP
FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON FOR THE NORTHERN
SIERRA...WITH LESS FOR MONO COUNTY. THIS WOULD ARGUE FOR 15 INCHES
IN 24 HOURS AT A 10 TO 1 RATIO...A VERY SOLID SNOW ADVISORY.
HOWEVER...WITH BETTER RATIOS AFTER THE FRONT IN MUCH COLDER AIR...WE
COULD SEE ENOUGH FOR A HEAVY SNOW WARNING IN THE SIERRA. WITH BOTH
ADVISORY OR WARNING CRITERIA FOR SNOWFALL POSSIBLE...WILL LEAVE THE
WINTER STORM WATCH UP AS IS FOR THE DAYSHIFT.

FOR THE LOWER VALLEYS...SNOW LEVELS SHOULD FALL TO THE VALLEY FLOORS
BY MIDDAY SATURDAY. WITH THE HUGE INSTABILITY ALOFT AND A SECONDARY
VORT MAX PROGGED TO SLIDE THROUGH IN THE EVENING...SNOW SHOWERS
SHOULD GO ALL DAY WITH ACCUMULATIONS LOOKING PRETTY GOOD AT THIS
TIME. THE GFS PAINTS AN ESPECIALLY PERSISTENT PRECIP BAND AROUND
SURPRISE VALLEY...WHICH MAKES SENSE GIVEN THE SECONDARY SHOT OF COLD
AIR TO SQUEEZE OUT MORE SNOW SHOWERS SATURDAY AFTERNOON AND EVENING.

SATURDAY NIGHT...SNOW SHOWERS TAPER OFF AS THE SHORT WAVE MOVES
EAST. SUNDAY LOOKS CHILLY INDEED WITH -12 TO -15C AIR AT 700 MB
MOVING IN. WE WILL BARELY REACH 40 IN THE LOWER VALLEYS...WITH
SINGLE DIGITS AND TEENS FOR VALLEYS SUNDAY NIGHT. IT WILL BE A THREE
DOG NIGHT INDEED. SNYDER
&&

.LONG TERM...MONDAY THROUGH THURSDAY
SPLIT FLOW TO CONTINUE OVER THE EASTERN PACIFIC THROUGH THE PERIOD.
THE LATEST OPERATIONAL GFS IS NOW THE SLOWEST MODEL WITH THE
TUESDAY/WEDNESDAY SYSTEM. THE GFS BRINGS OVERRUNNING PRECIPITATION
TO THE SIERRA AND NORTHEAST CA TUESDAY WITH THE TROUGH MOVING
THROUGH CA WEDNESDAY. A QUICK LOOK AT THE LATEST ENSEMBLE CHARTS
SHOW A MAJORITY BRINGING THE TROUGH THROUGH FASTER...AROUND 12 HOURS
FASTER...SIMILAR TO THE ECMWF...CANADIAN AND UKMET. HAVE GONE WITH
THIS FASTER TIMING IN THE LATEST GRID PACKAGE...TRENDING POPS UPWARD
TUESDAY AND TUESDAY NIGHT. HAVE STAYED BELOW MOS GUIDANCE ON
TEMPERATURES...ESPECIALLY WEDNESDAY WHERE THE THINKING IS THE TROUGH
WILL HAVE MOVED EAST OF THE AREA RATHER THAN STILL BEING OVER CA.
MODELS ARE IN BETTER AGREEMENT THURSDAY AS RIDGE BUILDS OFF THE WEST
COAST WITH SURFACE HIGH TO THE NORTH AND COOL NORTH FLOW OVER THE
AREA KEEPING TEMPERATURES DOWN. RC
&&

.AVIATION...
VFR CONDITIONS THROUGH THIS AFTERNOON THEN DETERIORATING CONDITIONS
IN THE SIERRA AND NORTHEAST CA AFTER 03Z AS COLD FRONT APPROACHES.
WINDS WILL INCREASE FROM THE SOUTH THIS AFTERNOON AND CONTINUE
TONIGHT AHEAD OF THE NEXT FRONT. WIDESPREAD MVFR CONDITIONS DUE LATE
TONIGHT OVER THE SIERRA AND SPREADING ACROSS WESTERN NEVADA SITES
SATURDAY. RC
&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY EVENING
     FOR NVZ002.
     WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SATURDAY
     EVENING FOR NVZ003-NVZ005.
     LAKE WIND ADVISORY THIS AFTERNOON AND EVENING FOR LAKE TAHOE
     AND PYRAMID LAKE.

CA...WINTER STORM WATCH FROM THIS EVENING THROUGH SATURDAY
     EVENING FOR CAZ071-CAZ072.
     WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SATURDAY
     EVENING FOR CAZ070.
     WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING
     FOR CAZ073.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RENO NV
656 AM PST FRI JAN 13 2006

CAZ070>073-NVZ001>005-141500-
SURPRISE VALLEY CALIFORNIA-LASSEN-EASTERN PLUMAS-
EASTERN SIERRA COUNTIES-GREATER LAKE TAHOE AREA-MONO-
MINERAL AND SOUTHERN LYON COUNTIES-GREATER RENO-CARSON CITY-
MINDEN AREA-WESTERN NEVADA BASIN AND RANGE INCLUDING PYRAMID LAKE-
NORTHERN WASHOE COUNTY-
656 AM PST FRI JAN 13 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE EASTERN SIERRA...
NORTHEAST CALIFORNIA AND WESTERN NEVADA.

.DAY ONE...TODAY AND TONIGHT
SOUTHERLY WINDS WILL STRENGTHEN AND BECOME GUSTY AT TIMES THIS
AFTERNOON AND EVENING AS A DEEP TROUGH APPROACHES THE SIERRA AND
WESTERN NEVADA. IN ADDITION...LAKE WIND ADVISORIES HAVE BEEN
ISSUED FOR LAKE TAHOE AND PYRAMID LAKE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
THE ASSOCIATED COLD FRONT WILL MOVE INTO THE SIERRA EARLY SATURDAY
MORNING AND INTO WESTERN NEVADA BY MID DAY. SNOW LEVELS WILL
RAPIDLY DROP WITH THIS SYSTEM AS PRECIPITATION MOVES INTO THE
AREA. PLEASE REFER TO THE WINTER STORM WATCH /WWUS45 KREV
RNOWSWREV/ ISSUED FOR THE SIERRA...NORTHEASTERN CALIFORNIA...AND
FAR NORTHWESTERN NEVADA VALLEYS (INCLUDING RENO AND CARSON CITY)
FOR FURTHER DETAILS.

ANOTHER POTENTIALLY STRONGER SYSTEM LOOKS TO MOVE INTO THE REGION
ON WEDNESDAY BRINGING MORE SIGNIFICANT SNOWFALL TO THE SIERRA AND
WESTERN NEVADA.

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ASKED TO REPORT SIGNIFICANT WEATHER EVENTS ACCORDING
TO ESTABLISHED CRITERIA.

JBONK