Heavy Snow in California, February 16 to 17, 2002

WESTERN NEVADA AND EASTERN CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
905 PM PST SAT FEB 16 2002

UPPER LOW CONTINUES TO ADVANCE TOWARD THE SAN FRANCISCO BAY WHILE
THE BAND OF HEAVY PRECIP IS WORKING UP THE WEST SLOPES OF THE
SIERRA. RADAR ECHOES IN NORTHWEST NV ARE LIKELY JUST VIRGA AND MID
LEVEL CLOUDS SINCE NO MEASURABLE RAIN HAS BEEN REPORTED BY LOVELOCK
ASOS OR RAWS SITES.

ONSET OF PRECIP IS LIKELY TO REACH THE TAHOE AREA BETWEEN 10 AND 11
PM...AND SPREAD TO THE LASSEN AND RENO ZONES AROUND MIDNIGHT. A
NOWCAST WAS ISSUED TO HIGHLIGHT THIS TIMING. THE AVN MODEL IS MORE
AGGRESSIVE IN UPWARD VERTICAL MOTION AND QPF VALUES EAST OF THE
SIERRA...AND BASED ON THE POSITION OF THE UPPER LOW AND EXPECTED
DECREASE IN 700 MB WINDS OVERNIGHT...THE ETA IS LIKELY SHADOWING OUT
THE LEE SIDE TOO MUCH. SOME HEAVIER SNOW SHOULD STILL BE FALLING IN
THE ADVISORY AREA IN THE EARLY PART OF THE SECOND PERIOD SO THE
ADVISORY WILL BE EXTENDED UNTIL 10 AM WITH THIS UPDATE PACKAGE. SNOW
LEVELS ARE TRICKY IN ZONE 71 AND ON MANY OCCASIONS AREAS SUCH AS
PORTOLA...GRAEAGLE OR THE SIERRA VALLEY BELOW 5000 FEET END UP WITH
MORE SNOW THAN EXPECTED. THEREFORE THE ELEVATION LIMIT WILL BE
REMOVED WITH THE ADVISORY IN THAT ZONE.

THE AVN SETS UP SOME WRAP AROUND MOISTURE BETWEEN SUSANVILLE AND
GERLACH ON SUNDAY AND SWINGS IT ACROSS RENO AND LOVELOCK SUNDAY
NIGHT. ALTHOUGH PLACEMENT OF THIS QPF BULLSEYE IS STILL IN
QUESTION...THE PROXIMITY OF THE LOW COMBINED WITH MARGINALLY
UNSTABLE CONDITIONS WILL KEEP THE THREAT OF ACCUMULATING SNOW AND
SNOW SHOWERS IN MOST ZONES ON SUNDAY. LIKELY POPS WILL BE CARRIED
OVER IN ALL AREAS EXCEPT ZONE 1 FOR SUNDAY. MJD

.REV...SNOW ADVISORY TONIGHT AND SUNDAY MORNING ZONE 71 AND 2/72.
       SNOW ADVISORY ABOVE 7000 FEET TONIGHT AND SUNDAY MORNING
       ZONE 73.