High Wind and Strong Wind in Nevada, April 6 to 7, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
316 AM PDT WED APR 6 2011

.SHORT TERM...
FORECAST IS STILL ON TRACK FOR GUSTY WINDS FOLLOWED BY A STRONG
FROPA WEDNESDAY EVENING (NORTH) TO AROUND DAYBREAK THURSDAY (SOUTH).
THE MAIN FORECAST CHANGES WERE TO THROW IN A SLIGHT CHANCE OF
THUNDERSTORMS FOR THURSDAY AFTERNOON AND EVENING AND TO POP OUT
WINTER WEATHER ADVISORIES FOR MUCH OF THE CWA WEDNESDAY NIGHT AND
THURSDAY.

THE VERY COLD UPPER LOW OF INTEREST FOR WEDNESDAY NIGHT AND THURSDAY
IS CURRENTLY POSITIONED OFF THE BRITISH COLUMBIA COAST. AS JET
ENERGY DIVES DOWN THE BACKSIDE OF THE LOW TODAY IT WILL BEGIN TO
DIG INTO THE NORTHWEST CONUS AND PUSH A STRONG COLD FRONT INTO
NORTHWEST CALIFORNIA BY LATE AFTERNOON.

THE FIRST ITEM OF INTEREST WILL BE GUSTY WINDS AHEAD OF THE COLD
FRONT. THEY WILL BY NO MEANS BE REMARKABLE FOR THIS PART OF THE
COUNTRY BUT LOCAL GUSTS OF 55 TO 60 MPH ARE EXPECTED RIGHT AHEAD
OF THE COLD FRONT...WITH WINDS FALLING QUICKLY AS MOISTURE INCREASES
ALONG AND BEHIND THE FROPA.

PRECIPITATION WISE...ATTENTION WILL TURN TO THE SNOWFALL POTENTIAL
FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING. MODELS REMAIN
QUITE CONSISTENT ON THE GENERAL SYNOPTIC FEATURES OF JET POSITION
AND FROPA TIMING SO CONFIDENCE IS HIGH IN AT LEAST A LIGHT SNOWFALL
IN MANY LOWER ELEVATIONS WITH SOLID ADVISORY AMOUNTS IN THE SIERRA.
HOWEVER...THE BEST FOCUS APPEARS TO BE SOUTH OF A SUSANVILLE TO
GERLACH LINE AS FRONTOGENESIS AND PRECIP ALONG THE FRONT REALLY
FIRE UP AS THE NOSE OF A 90 TO 100 KT JET STREAK MOVES OVER THE
NORTHERN SIERRA. GFS CROSS SECTIONS LINE UP THE BROAD UPPER
FORCING WITH THE JET STREAK AND FRONTOGENETIC FORCING NEAR AND A
BIT NORTH OF RENO VERY WELL. IN ADDITION...UNSTABLE AIR AND
FAVORABLE CROSS SIERRA UPSLOPE FLOW WILL DAMPEN THE TYPICAL LEE
SIDE SHADOWING AND ENSURE A SOLID FRONTAL SNOW BAND FROM THE
SIERRA OUT INTO NORTHERN AND NORTH CENTRAL NEVADA EARLY THURSDAY
MORNING.

THE TIMING IS EXCELLENT FOR SNOWFALL IMPACTS IN THE LOWER ELEVATIONS
OF WESTERN NEVADA THURSDAY MORNING SO WE HAVE PUT OUT A WINTER
WEATHER ADVISORY HIGHLIGHTING THIS ISSUE FOR THE THURSDAY MORNING
RUSH IN THE RENO AND CARSON CITY AREA.

THURSDAY AFTERNOON AND EVENING...THE POST FRONTAL PRECIP TURNS
SHOWERY AS THE -32C TO -34C COLD POOL SETTLES OVERHEAD. I HAVE
ADDED A SLIGHT CHANCE OF THUNDER WITH STEEP MID LEVEL LAPSE RATES
OVERHEAD. AS IT WILL BE HARD TO PINPOINT WHERE THUNDER IS MOST
LIKELY I HAVE BLANKETED THE ENTIRE CWA WITH THE SLIGHT CHANCE.

FRIDAY...THE UPPER COLD POOL DROPS INTO SOUTHERN CALIFORNIA WITH
COLD NORTHEAST FLOW ALOFT KEEPING HIGHS WELL BELOW AVERAGE ALONG
WITH SCATTERED SNOW SHOWERS SOUTH OF INTERSTATE 80. WASN'T IT 80
IN RENO A FEW DAYS BACK? SNYDER

.LONG TERM...SATURDAY THROUGH TUESDAY...
DIFFERENCES CONTINUE TO SHOW UP IN THE MODELS THIS MORNING WITH THE
GEM REMAINING THE BIGGEST OUTLIER. THE GFS/ECMWF ARE IN DECENT
AGREEMENT ON THE LARGE SCALE BUT DIFFER ON THE DETAILS...ESPECIALLY
WITH REGARD TO TROUGH EARLY NEXT WEEK. THE GFS IS SHOWING MORE SPLIT
WITH THIS FEATURE AND IS DECIDEDLY SLOWER AND WEAKER THAN ITS
PREVIOUS RUNS WITH QUITE A BIT OF SPREAD IN ITS ENSEMBLE SUITE. THE
ECMWF HAS MAINTAINED CONTINUITY SHOWING A MORE CONSOLIDATED TROUGH
LATE SUNDAY NIGHT INTO MONDAY. DID NOT MAKE ANY CHANGES TO THE
ONGOING FORECAST DUE TO THE UNCERTAINTY. IT SHOWS POPS FOCUSED
AROUND SUN NIGHT-MON. IN ANY CASE IT DOES NOT APPEAR TO BE A BIG
SYSTEM WITH MAIN ANOMALY AT 500MB PASSING THROUGH CANADA/PACNW.

TEMPERATURES WILL BE SLOW TO CLIMB SAT AS THIS WEEKS UPPER LOW EXITS
AND A GENERAL NORTH FLOW ALOFT PREVAILS. AFTER SAT...THERE SHOULD BE
A MODEST WARMUP WITH TEMPERATURES CLIMBING BACK CLOSER TO
CLIMATOLOGY WHICH WOULD BE LOWER 50S FOR SIERRA VALLEYS AND LOWER
60S IN THE LOWER VALLEY FLOORS. HOHMANN
&&

.AVIATION...
WINDS INCREASING TODAY WITH GUSTS APPROACHING 35-40KT AT AREA
TERMINALS THIS AFTERNOON AND EVENING. RIDGE WINDS WILL INCREASE TO
70KT THIS AFTERNOON AND 90KT TONIGHT AND EARLY THU.

VERY COLD UPPER LOW AND ASSOCIATED STRONG COLD FRONT WILL WORK INTO
THE AREA THU MORNING WITH SNOW SHOWERS AND REDUCED CIGS/VSBY.
AIRMASS WILL REMAIN UNSTABLE BEHIND FRONT WITH SNOW PELLETS AND
ISOLATED THUNDER THU AFTERNOON.

FOR KRNO...THERE WILL LIKELY BE A SHORT PERIOD (ABOUT AN HOUR) OF
STRONG WIND GUSTS TO 35KT AND HEAVY SNOW ASSOCIATED WITH THE MAIN
FRONTAL PASSAGE. RIGHT NOW IT APPEARS FRONT WILL PASS SOMETIME
BETWEEN 10Z-14Z. INSTRUMENT FLIGHT RULES LIKELY DURING PERIOD AND
THEN ON AND OFF THROUGH THE DAY THU. DUE TO INTENSITY OF SNOWFALL
AND TIME OF DAY...ACCUMULATIONS UP TO AN INCH ON THE RUNWAY THU
MORNING THRU 18Z. GENERALLY LIGHT ACCUMULATION AFTER 18Z IN BRIEF
HEAVY PELLET SHOWERS.

FOR KTVL/KTRK...SNOW WILL BEGIN 02Z-06Z THIS EVENING AND THEN
INCREASE IN INTENSITY 06Z-18Z. EXPECT CONDITIONS BELOW ALL MINIMUMS
WITH 4 TO 8 INCHES ACCUMULATION. AFTER 18Z...CONDITIONS WILL BECOME
MORE SHOWERY WITH LIGHTER INTENSITY SNOW AND EMBEDDED HEAVIER SNOW
SHOWERS. HOHMANN
&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM PDT THIS
     EVENING FOR LAKE TAHOE IN NVZ002.

     WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 11 AM PDT
     THURSDAY NVZ002.

     WIND ADVISORY FROM 5 PM THIS AFTERNOON TO 8 AM PDT THURSDAY
     NVZ001.

     WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 11 AM PDT
     THURSDAY NVZ003-004.

     WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING
     NVZ003-004.

CA...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 11 AM PDT
     THURSDAY CAZ071.

     WINTER WEATHER ADVISORY FROM 2 AM TO 2 PM PDT THURSDAY CAZ073.

     WIND ADVISORY FROM 5 PM THIS AFTERNOON TO 2 AM PDT THURSDAY
     CAZ073.

     LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM PDT THIS
     EVENING FOR LAKE TAHOE IN CAZ072.

     WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 11 AM PDT
     THURSDAY CAZ072.

&&

HTTP://WEATHER.GOV/RENO