Fire Weather Outlook Discussion
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FNUS21 KWNS 050706
FWDDY1

DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0205 AM CDT WED AUG 05 2015

VALID 051200Z - 061200Z

...SYNOPSIS...
EARLY-MORNING MOISTURE-CHANNEL IMAGERY INDICATES A COMPACT MID-LEVEL
CYCLONE TRACKING ENEWD ACROSS NRN CA...ON THE SRN PERIPHERY OF A
TROUGH DIGGING INTO THE NWRN CONUS FROM BRITISH COLUMBIA. THIS
TROUGH IS FORECAST TO CONTINUE AMPLIFYING SEWD INTO THE NWRN CONUS
THROUGH THE PERIOD...WITH THE CYCLONE TO ITS S ADVANCING ENEWD TO
THE HIGH PLAINS. BOTH OF THESE FEATURES WILL INFLUENCE THE
FIRE-WEATHER POTENTIAL ACROSS PORTIONS OF THE WRN CONUS TODAY.
ELSEWHERE...A MID-LEVEL RIDGE WILL PERSIST OVER THE SWRN
CONUS...WHILE CYCLONIC FLOW OVERLIES THE NORTHEAST.

...PARTS OF CNTRL/ERN WA INTO NRN ORE...
MODESTLY ENHANCED TROPOSPHERIC FLOW ACCOMPANYING THE AMPLIFYING
MID-LEVEL TROUGH WILL SUPPORT SWLY TO WLY SFC WINDS AROUND 10-20 MPH
AS VERTICAL MIXING STRENGTHENS THROUGH THE DAY. THESE WINDS ARE
FORECAST TO COMBINE WITH DOWNSLOPE-FLOW-ENHANCED WARMING/DRYING TO
SUPPORT MINIMUM RH VALUES FROM THE TEENS TO THE 20S...YIELDING
ELEVATED FIRE-WEATHER CONDITIONS GIVEN DRY/VERY DRY FUELS IN PLACE.
BORDERLINE-CRITICAL FIRE-WEATHER CONDITIONS CANNOT BE RULED OUT ON A
BRIEF/SPOTTY BASIS NEAR THE COLUMBIA RIVER. HOWEVER...THE LACK OF
STRONGER LOW-LEVEL FLOW LIMITS CONFIDENCE IN A MORE SUBSTANTIAL
CRITICAL RISK...PRECLUDING CRITICAL DESIGNATION AT THIS TIME.

...PORTIONS OF CNTRL/WRN UT INTO FAR ERN NV...
STRONG VERTICAL MIXING WILL MANIFEST ENHANCED FLOW ALOFT --
ACCOMPANYING THE TIGHTENED MID-LEVEL HEIGHT GRADIENT S OF THE
COMPACT CYCLONE -- AT THE SFC AS SWLY WINDS AROUND 15-20 MPH WITH
HIGHER GUSTS. RH VALUES ARE EXPECTED TO FALL TO 10-15 PERCENT AS
TEMPERATURES WARM INTO THE 80S AND 90S. GIVEN THE PRESENCE OF DRY
FUELS...THESE FACTORS WILL SUPPORT AN ELEVATED FIRE-WEATHER RISK.
HOWEVER...THE LACK OF STRONGER LOW/MID-LEVEL FLOW SHOULD PREVENT
CRITICALLY STRONG WINDS FROM OCCURRING ON ANY MORE THAN A
BRIEF...SPOTTY...AND/OR MARGINAL BASIS.

...PORTIONS OF SRN ID...NRN NV...FAR NWRN UT...FAR SERN ORE...
THE LATEST OBSERVATIONAL DATA AND SHORT-RANGE MODEL GUIDANCE SUGGEST
THAT ENHANCED ASCENT/INSTABILITY ACCOMPANYING THE AFOREMENTIONED
COMPACT CYCLONE WILL BE CROSSING THE REGION THIS AFTERNOON. COUPLED
WITH DIURNALLY ENHANCED OROGRAPHIC CIRCULATIONS...THE
CYCLONE-ENHANCED ASCENT WILL ENCOURAGE THE DEVELOPMENT OF ISOLATED
TO WIDELY SCATTERED THUNDERSTORMS THIS AFTERNOON. GIVEN 30-60 MPH OF
FLOW WITHIN THE CONVECTIVE-CLOUD LAYER ENCOURAGING FAST THUNDERSTORM
MOTIONS...AND A MODESTLY DEEP BOUNDARY LAYER FACILITATING SUB-CLOUD
EVAPORATION...PRECIPITATION AMOUNTS WILL BE LIMITED. THESE
FACTORS...COMBINED WITH PW VALUES AROUND 0.60-0.85 INCH BASED ON
TUESDAY-EVENING OBSERVED SOUNDINGS AND GPS DATA...SUGGEST THAT A
RISK FOR ISOLATED DRY THUNDERSTORMS WILL EXIST ACROSS PARTS OF SRN
ID...NRN NV...FAR NWRN UT...AND FAR SERN ORE...WHERE AREAS OF DRY
AND VERY DRY FUELS EXIST. ISOLATED DRY-THUNDERSTORM DESIGNATION HAS
BEEN INCLUDED ACROSS PORTIONS OF THESE REGIONS. STRONG...GUSTY...AND
ERRATIC OUTFLOW WINDS ACCOMPANYING THIS ACTIVITY WILL HAVE THE
POTENTIAL TO INFLUENCE EXISTING AND/OR NEW FIRES.

SURROUNDING THE ISOLATED DRY-THUNDERSTORM AREA...THE PRESENCE OF
EITHER MOISTER FUELS MITIGATING FIRE-WEATHER POTENTIAL AND/OR
LESS-FAVORABLE THERMODYNAMIC PROFILES FOR DRY-THUNDERSTORM POTENTIAL
WILL EXIST...AND PRECLUDE LARGER AREAL DESIGNATION AT THIS TIME.

..COHEN.. 08/05/2015

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



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