Fire Weather Outlook Discussion
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FNUS21 KWNS 040826
FWDDY1

DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0325 AM CDT FRI SEP 04 2015

VALID 041200Z - 051200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF ERN/SRN NV AND WRN
UT...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NWRN NV...

...SYNOPSIS...
A MID/UPPER-LEVEL TROUGH /WITH SEVERAL EMBEDDED VORTICITY MAXIMA/
WILL BE ESTABLISHED OVER MUCH OF THE WEST COAST/NRN ROCKIES/GREAT
BASIN TODAY. ELSEWHERE...BROAD RIDGING WILL BE SITUATED OVER MOST OF
THE CNTRL/ERN CONUS. THE ASSOCIATED SFC RESPONSE WILL FEATURE A
STATIONARY FRONT STRETCHING FROM SWRN MT SWWD TOWARDS NWRN
NV...WHILE CYCLOGENESIS OCCURS OVER NERN NV/FAR SRN ID.

...PORTIONS OF THE GREAT BASIN...
TWO PRIMARY AREAS OF ENHANCED FIRE-WEATHER CONCERN WILL EXIST TODAY.
THE FIRST WILL STRETCH FROM SRN NV NEWD INTO NWRN UT...AS A BELT OF
STRONG 700-MB FLOW PERSISTS OVER THIS CORRIDOR. WITH THE ONSET OF
DIURNAL MIXING...VERTICAL TRANSFER OF THIS HIGHER-MOMENTUM AIR WILL
YIELD SWLY WINDS AROUND 25-35 MPH SUSTAINED /WITH HIGHER GUSTS/. 00Z
RAOBS DEPICT A DRY AIR MASS /CHARACTERIZED BY PWATS AROUND 0.3-0.5
INCHES/ OVER MUCH OF THE REGION...WHICH WILL FAVOR A RAPID REDUCTION
OF SFC RH VALUES BELOW 15 PERCENT AS THE AFOREMENTIONED MIXING
ENSUES. WITH DRY FUELS STILL PRESENT...THESE METEOROLOGICAL
CONDITIONS WILL SUPPORT A CRITICAL FIRE-WX THREAT.

THE SECOND FOCUSED AREA OF CONCERN WILL EXIST OVER NWRN NV. AS AN
EMBEDDED IMPULSE ALOFT TRANSLATES EWD OVER THE NRN SIERRA
NEVADA...ENHANCED WLY FLOW WILL PROMOTE GUSTY DOWNSLOPE WINDS IN THE
LEE OF THE MOUNTAINS. RH VALUES ARE LIKELY TO FALL TO AROUND 10-15
PERCENT...WHICH IN COMBINATION WITH DRY FUELS...WILL MAINTAIN A
CRITICAL THREAT HERE AS WELL.

SURROUNDING THE CRITICAL DESIGNATIONS...WEAKER WINDS/HIGHER RH
VALUES WILL TEMPER FIRE-WX CONCERNS SOME...BUT SHOULD STILL SUPPORT
AN ELEVATED THREAT. THUS...THE PREVIOUS DELINEATION REMAINS
GENERALLY UNCHANGED.

..PICCA.. 09/04/2015

...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...




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