Fire Weather Outlook Discussion
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FNUS28 KWNS 032004
FWDD38

DAY 3-8 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0304 PM CDT MON AUG 03 2015

VALID 051200Z - 111200Z

AN AMPLIFIED...YET PROGRESSIVE SYNOPTIC PATTERN WILL PERSIST ACROSS
THE NORTHERN TIER OF THE U.S. WITH SEVERAL SHORTWAVE TROUGHS
PROGRESSING THROUGH DRY AREAS OF THE WEST INCREASING FIRE WEATHER
CONCERNS THERE.  A LONG-WAVE TROUGH OVER THE NORTHEASTERN U.S. AND
ADJACENT PARTS OF CANADA AT THE BEGINNING OF THE FORECAST PERIOD
WILL GRADUALLY MOVE EASTWARD AWAY FROM THE CONUS...ONLY TO BE
REPLACED BY A LOWER AMPLITUDE TROUGH NEAR THE OHIO VALLEY ON D5/FRI.
 A VIGOROUS SHORTWAVE WILL INTO THE PACIFIC NORTHWEST AND NORTHERN
ROCKIES ON D4/THU...THEN WEAKEN AS IT EJECTS ACROSS THE NORTHERN
PLAINS ON D5/FRI.  YET ANOTHER VIGOROUS SHORTWAVE TROUGH WILL ENTER
CALIFORNIA AND NEVADA ON D5/FRI AND MOVE EAST INTO UTAH BY
D6/SAT...LEADING TO INCREASED FIRE WEATHER CONCERNS THERE.

...D3/WED: NORTH CENTRAL OREGON INTO SOUTHEASTERN WASHINGTON...
ELEVATED WESTERLY MID-LEVEL FLOW WILL SPREAD ATOP THE REGION IN
ADVANCE OF A VIGOROUS SOUTHEASTWARD-MOVING SHORTWAVE OVER BRITISH
COLUMBIA AT THE BEGINNING OF D3/WED.  INSOLATION AND DOWNWARD
TRANSPORT OF THIS HIGHER MOMENTUM AIR WILL RESULT IN 10-15 MPH
WESTERLY SURFACE FLOW /LOCALLY HIGHER NEAR FAVORED TERRAIN AREAS/.
AFTERNOON RH VALUES WILL BE SLIGHTLY LOWER THAN IN RECENT DAYS...BUT
WILL DROP TO AROUND 15-20 PERCENT.  THESE FACTORS SUGGEST AT LEAST A
40 PERCENT PROBABILITY OF CRITICAL FIRE WEATHER CONDITIONS ACROSS
THE AREA...AND A DELINEATION HAS BEEN MADE TO ADDRESS THE THREAT.

...D5/FRI AND D6/SAT: PARTS OF NEVADA AND UTAH...
AS ANOTHER VIGOROUS TROUGH APPROACHES THE AREA FROM THE EASTERN
PACIFIC...TIGHTENING GEOPOTENTIAL/SURFACE PRESSURE GRADIENTS ACROSS
THE REGION WILL RESULT IN STRENGTHENING FLOW AT ALL LEVELS AMIDST A
RELATIVELY DRY BOUNDARY LAYER WITH CRITICAL SURFACE RH VALUES.
CONSISTENCY IN LATEST MODEL GUIDANCE AND PATTERN RECOGNITION /I.E.
BREAKDOWN OF UPPER RIDGE/ YIELDS HIGH CONFIDENCE THAT CRITICAL
ATMOSPHERIC FIRE WEATHER CONDITIONS WILL BE OBSERVED ACROSS PARTS OF
NEVADA ON D5/FRI...WITH SOMEWHAT LESSER CONFIDENCE OF CRITICAL FIRE
WEATHER CONDITIONS IN WESTERN/CENTRAL UTAH ON D6/SAT.  THE BIGGEST
LIMITING FACTOR FOR A HIGHER FIRE WEATHER THREAT IN THESE AREAS IS
FUEL STATE...WHICH MAY ONLY BE MARGINALLY RECEPTIVE FOR FIRE GROWTH
GIVEN ANTECEDENT RAINFALL IN SOME AREAS.  RELATIVELY LOW
PROBABILITIES HAVE BEEN INTRODUCED FOR PARTS OF NEVADA ON D5/FRI
WITH THE ANTICIPATION THAT FUTURE FORECASTS/MODEL CYCLES AND FUEL
STATES WILL HELP CLARIFY THE FIRE WEATHER SCENARIO THERE.

THUNDERSTORMS /SOME DRY/ ARE ALSO LIKELY IN ADVANCE OF THE TROUGH
GIVEN INCREASING INSTABILITY ALOFT ALONG WITH 40+ KNOT MID-LEVEL
FLOW.  A DRY THUNDER DELINEATION HAS ALSO BEEN MADE FOR NORTHERN
NEVADA ON D5/FRI TO ADDRESS THIS THREAT.

..COOK.. 08/03/2015

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



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