485
FXUS65 KREV 212259
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
259 PM PST SAT NOV 21 2009
SHORT TERM
NEXT SYSTEM TO MOVE IN TONIGHT IS JUST OFF THE COAST WITH CLOUD
SHIELD ONTO NW CA. SYSTEM IS POTENT AND SMALL...BUT WILL DEAL JUST
A GLANCING BLOW TO THE AREA AS IT IS EXPECTED TO MOVE INTO OR/WA.
DECENT AMOUNT OF ISENTROPIC LIFT NORTH OF SUSANVILLE/GERLACH AFTER
06Z SO HAVE INCREASED POPS TO 50/60 PCT ACROSS THESE AREAS.
AMOUNTS WILL BE LIGHT...AND PCPN ALMOST ALL IN THE FORM OF SNOW
DESPITE WARMING TEMPS ALOFT. PROG SOUNDINGS ALL SHOW NEAR
ISOTHERMAL TEMP PROFILE THROUGH 15Z. COLD FRONT WITH SYSTEM JUST
GLANCES THE AREA SUN MORNING...SO HAVE KEPT THE HIGHER POPS FOR
ANOTHER 6 HRS THRU MID-MORNING. BY THEN...MOISTURE AND FORCING
WITH SYSTEM WILL HAVE RACED EWD.
700 MB WINDS ALSO INCREASE NEAR THE OREGON BORDER TO NEAR 60 KTS
BY 12Z. HOWEVER...THERMODYNAMIC PROFILE IS NOT FAVORABLE FOR
MIXING THESE TO SFC OR FOR MTN WAVES. AS PROFILE IMPROVES BY
18Z...WINDS DROP OFF TO NEAR 35-40 KTS ACROSS MANY AREAS NORTH OF
HWY 50. EXPECT A BREEZY DAY TOMORROW MOST AREAS WITH SOME GUSTS UP
TO 35-40 MPH...BUT NOTHING LIKE FRIDAY. HOISTED LAKE WIND
ADVISORIES FOR TAHOE/PYRAMID WHICH SHOULD BE A BIT CHOPPY WITH THE
WINDS AND WAVES AS HIGH AS 3 FEET.
BEHIND SYSTEM...RIDGE BUILDS IN FOR MON/TUE. RIDGE IS FAIRLY FLAT
SO IT WILL BE DIRTY WITH MID/HIGH CLOUDS MOVING THROUGH THE NORTH
AT TIMES. TEMPS WILL BE FAIRLY FLAT THROUGH THE PERIOD IN VALLEYS
WITH GOOD MIXING TOMORRW BECOMING POOR BY MON WITH LIGHT NE SFC
WINDS AND WARMING TEMPS ALOFT. MTNS WILL SEE BETTER MIXING AND
GRADUALLY WARMING TEMPS THROUGH PERIOD TO A FEW DEGREES ABOVE
NORMAL. WALLMANN
LONG TERM...WEDNESDAY THROUGH SATURDAY
RIDGE INTACT FOR MIDWEEK IN QUITE AMPLIFIED FLOW ACROSS NORTH
AMERICA. BY THURSDAY THE RIDGE BEGINS TO SHIFT EAST ACROSS THE
EASTERN GREAT BASIN AND NORTHERN ROCKIES ALLOWING SHORTWAVE ENERGY
TO MOVE TOWARD THE COAST.
FOR LATE IN THE WEEK MODEL SOLUTIONS DIFFER. THE LATEST EC BRINGS A
STRONGER AND COLDER SHORTWAVE TO THE SIERRA AND WESTERN NEVADA
THURSDAY NIGHT WHILE THE GFS AND GFS ENSEMBLE MEMBERS HAVE A SLOWER
SOLUTION WITH A SHALLOWER SHORTWAVE. THE EC WOULD POINT TO SHOWERS
FROM TAHOE AND I-80 NORTH THURSDAY NIGHT INTO FRIDAY WITH ANOTHER
INSIDE SLIDER TYPE IMPULSE REINFORCING THE COLDER AIR FOR SATURDAY.
THE LATEST GFS AND ENSEMBLES JUST GENERATE A GLANCING BLOW TO FAR
NORTHEAST CA AND NORTHWEST NEVADA FRIDAY WITH DRY AND MILD
CONDITIONS FOR SATURDAY. HOWEVER THE 06Z GFS RUN ALSO INDICATED AN
INSIDE SLIDER FOR SATURDAY NIGHT/SUNDAY MUCH LIKE THE LATEST EC...SO
WILL HAVE TO MONITOR FUTURE MODELS RUNS FOR THIS POTENTIAL.
CONTINUED WITH A CHANCE OF RAIN/SNOW ACROSS NORTHERN AREAS FOR
THANKSGIVING NIGHT THROUGH FRIDAY NIGHT WITH MODEL UNCERTAINTY.
FORECAST FOR THE WEEKEND AFTER THANKSGIVING IS EVEN MORE UNCERTAIN
AS MENTIONED ABOVE BUT WILL LEAVE THAT PERIOD DRY FOR NOW.
TEMPERATURES WILL BE NEAR NORMAL IN VALLEY LOCATIONS WITH OVERNIGHT
INVERSIONS...WHILE RIDGES WILL WARM MORE UNDER RIDGE. ALSO
ANTICIPATE BREEZY TO WINDY CONDITIONS FOR LATER IN THE WEEK. JAH
AVIATION
A SHORTWAVE MOVING INTO NORTHERN CA AND THE PACIFIC NORTHWEST WILL
SPREAD CLOUDS AND RAIN/SNOW SHOWERS ACROSS THE SIERRA FROM TAHOE
NORTH AFTER MIDNIGHT THROUGH SUNDAY AFTERNOON. THE INCREASE IN
MOISTURE WILL BRING MVFR CEILINGS TO THE SIERRA WITH MOUNTAIN
OBSCUREMENT.
WINDS WILL INCREASE AFTER 06Z TONIGHT WITH RIDGE WINDS 50-60KTS FROM
TAHOE NORTH. VALLEY LOCATIONS FROM RENO NORTH WILL SEE GUSTS TO
30KTS AFTER 18Z SUNDAY. JAH
REV WATCHES/WARNINGS/ADVISORIES
NV...LAKE WIND ADVISORY FROM 10 AM TO 7 PM PST SUNDAY FOR NVZ004.
LAKE WIND ADVISORY FROM 7 AM TO 7 PM PST SUNDAY FOR NVZ002.
CA...LAKE WIND ADVISORY FROM 7 AM TO 7 PM PST SUNDAY FOR CAZ072.
HTTP://WEATHER.GOV/RENO
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