000
FXUS65 KREV 171022
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
322 AM PDT THU MAY 17 2012
.SHORT TERM...
HIGH CLOUD COVERAGE CONTINUES TO INCREASE AHEAD OF TROF
APPROACHING THE CA COAST. THIS SYSTEM WILL BRING INCREASED
MOISTURE TO NERN CA AND FAR NWRN NV BY MID-LATE MORNING, AND
ESPECIALLY DURING THE AFTERNOON. ALTHOUGH SOME INSTBY IS EXPECTED
THE PRESENCE OF WIDESPREAD CLOUD COVER COULD LIMIT TSTM FORMATION
THRU MOST OF THIS AFTN. THE BEST TSTM POTENTIAL MAY END UP
OCCURRING AFT 00Z ALONG THE LEADING EDGE OF THE COLD FRONT AS
FORCING BECOMES MORE FOCUSED IN AREAS FROM SRN LASSEN TO PYRAMID
LAKE SOUTHWARD TO NEAR I-80. IF THESE STORMS ARE ABLE TO DEVELOP,
GUST FRONT AND OUTFLOW INTERACTIONS COULD TRIGGER ADDITIONAL CELLS A
LITTLE FARTHER SOUTH THAN INDICATED BY THE MODEL QPF FIELDS, SO
HAVE EXTENDED THE POSSIBILITY OF TSTMS INTO THE TAHOE BASIN AND
FAR WRN NV DOWN TO NEAR HWY 50.
THE OTHER MAIN IMPACT TODAY WILL BE GUSTY WINDS THIS AFTN-EVE
AHEAD OF THE COLD FRONT, AND ALSO DUE TO GUST FRONTS AHEAD OF
CONVECTIVE CELLS. WIND GUSTS OF 40-45 MPH COULD PRODUCE LOCAL
AREAS OF BLOWING DUST IN PORTIONS OF W-CNTRL NV AND ERN MONO
COUNTY WHICH HAVE NOT RECEIVED MUCH RAIN DURING THE PAST WEEK. THE
FAR NORTH EDGE OF THIS BLOWING DUST AREA IS MERGED WITH MENTION OF
SHOWERS AND TSTMS WHERE GUST FRONTS COULD KICK UP SOME DUST BEFORE
THE RAIN CORES ARRIVE. IN MOST AREAS SOUTH OF I-80, HUMIDITY WILL
BE QUITE LOW RESULTING IN FIRE WEATHER IMPACTS WHICH WILL BE
DISCUSSED FURTHER IN THE FIRE WEATHER SECTION BELOW.
THE TROF AND ITS ASSOCIATED DYNAMICS WILL MOVE QUICKLY EAST
OVERNIGHT THRU EARLY FRI MORNING WITH MOST AREAS DRYING OUT EXCEPT
FOR A FEW LINGERING SHOWERS IN THE W-CNTRL NV BASIN.
DRY AND STABLE CONDITIONS WILL PREVAIL BOTH FRIDAY AND SATURDAY AS
NW FLOW ALOFT FRIDAY TRANSITIONS INTO A FLAT RIDGE BUILDING INTO
ERN CA-WRN NV. WINDS WILL BE LIGHT BOTH DAYS WITH AREAS OF CIRRUS
MOVING ACROSS THE REGION, AND FLAT LATE AFTN CUMULUS MAINLY NEAR
THE SIERRA.
TEMP GRADIENTS TODAY WILL BE TIGHT AS TEMPS IN THE NRN SIERRA
DECREASE THIS AFTERNOON WHILE THE HWY 95 CORRIDOR IN W-CNTRL NV
COULD APPROACH 90 DEGREES. ON FRIDAY, HIGHS WILL BE 5-10 DEGREES
COOLER ACROSS MOST OF THE REGION, EXCEPT UP TO 15 DEGREES COOLER
FOR W-CNTRL NV AS MOST LOWER ELEVATIONS WILL TOP OUT IN THE LOWER-
MID 70S. HIGHS WILL BE 5-10 DEGREES WARMER ON SATURDAY AS THE
RIDGE BUILDS IN. MJD
.LONG TERM...SUNDAY THROUGH WEDNESDAY...
NO MAJOR CHANGES AGAIN IN THE LONG TERM FORECAST. UPPER RIDGE
REMAINS IN PLACE OVER THE GREAT BASIN THROUGH SUNDAY, AS A TROUGH
MOVES INTO THE WEST COAST FOR EARLY NEXT WEEK. LATEST GFS RUNS ARE
COMING IN DEEPER WITH THE TROUGH INTO THE THE GREAT BASIN, WHICH
MATCHES UP BETTER WITH THE ECMWF AND GEM. THE MAJOR DIFFERENCE IS
THE GFS PUSHES THE TROUGH OUT QUICKLY WITH RIDGING BUILDING BACK
INTO THE WEST COAST BY MIDWEEK. THE 00Z EC/GEM KEEP THE TROUGH OVER
THE WEST THROUGH THE SECOND HALF OF NEXT WEEK. THESE DIFFERENCES
LEAD TO BELOW NORMAL CONFIDENCE PAST MONDAY.
TEMPERATURES SUNDAY WILL BE AROUND 10 DEGREES ABOVE NORMAL FOR LATE
MAY, HITTING THE UPPER 80S IN WESTERN NEVADA AND 70S IN THE SIERRA.
KEPT IN THE CHANCES OF SHOWERS MONDAY NIGHT THROUGH TUESDAY, DUE TO
FORCING FROM THE INCOMING TROUGH. TEMPERATURES WILL COOL OFF TO
START NEXT WEEK. DEPENDING ON IF THE GFS OR EC/GEM SOLUTION, THE
COOLER AIR MAY HANG AROUND THROUGH THE END OF THE WEEK OR WE COULD
BOUNCE BACK INTO ABOVE NORMAL TEMPERATURES. HOON
&&
.AVIATION...
COLD FRONT WILL PUSH INTO NORTHERN CA/NV TODAY, WITH W-SW WINDS
GUSTING TO 30-35KT. RIDGE WINDS OF 65KT WILL CREATE SOME LOW LEVEL
TURBULENCE DOWNSTREAM OF THE SIERRA.
SCATTERED SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS CAN BE
EXPECTED NORTH OF INTERSTATE 80 LATE THIS AFTERNOON AND INTO THE
EVENING. THESE AREN`T EXPECTED TO AFFECT KRNO, ALTHOUGH
INBOUND/OUTBOUND FLIGHTS COULD BE IMPACTED. HOON
&&
.FIRE WEATHER...
A TROUGH OF LOW PRESSURE WILL PUSH A COLD FRONT THROUGH THE REGION
BY THIS EVENING. AHEAD OF THE FRONT, SOUTHWEST TO WEST WINDS WILL
GUST UP TO 45 MPH. THIS WILL COMBINE WITH VERY DRY CONDITIONS SOUTH
OF INTERSTATE 80 TO CREATE CRITICAL FIRE WEATHER CONDITIONS THIS
AFTERNOON AND EARLY EVENING.
RED FLAG WARNING HAS BEEN ISSUED FOR FIRE ZONES 273, 450, 453, AND
459. PLEASE SEE THE PRODUCT FOR ADDITIONAL DETAILS. NORTH OF
INTERSTATE 80, MOISTURE MOVING INTO THE REGION WILL INCREASE THE
HUMIDITY, BUT WINDS WILL REMAIN GUSTY.
SCATTERED SHOWERS WITH A SLIGHT CHANCE OF THUNDERSTORMS NORTH OF
HIGHWAY 50 CAN BE EXPECTED WITH THE TROUGH THIS AFTERNOON AND
EVENING. THESE ISOLATED STORMS COULD START A FEW NEW FIRES TODAY,
ESPECIALLY IN THE DRIER AIRMASS SOUTH OF INTERSTATE 80 IN
WEST-CENTRAL NEVADA. ANY NEW FIRES FROM LIGHTNING STRIKES HAVE
POTENTIAL TO GROW QUICKLY WITH THE DRY CONDITIONS AND GUSTY WINDS.
DF/HOON
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...RED FLAG WARNING FROM NOON TODAY TO 7 PM PDT THIS EVENING
NVZ450-453.
LAKE WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM PDT THIS
EVENING FOR PYRAMID LAKE IN NVZ004.
LAKE WIND ADVISORY FROM NOON TODAY TO 11 PM PDT THIS EVENING FOR
LAKE TAHOE IN NVZ002.
RED FLAG WARNING FROM NOON TODAY TO 10 PM PDT THIS EVENING
NVZ459.
CA...RED FLAG WARNING FROM NOON TODAY TO 10 PM PDT THIS EVENING BELOW
8500 FEET FOR CAZ273.
LAKE WIND ADVISORY FROM NOON TODAY TO 11 PM PDT THIS EVENING FOR
LAKE TAHOE IN CAZ072.
&&
$$
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NWS REV Office Area Forecast Discussion
