Fire Weather Outlook Discussion
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FNUS22 KWNS 281858
FWDDY2

DAY 2 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0158 PM CDT FRI AUG 28 2015

VALID 291200Z - 301200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF ERN WA AND THE ID
PANHANDLE...

THE ELEVATED FIRE-WEATHER AREA HAS BEEN EXTENDED SWD ACROSS PORTIONS
OF CNTRL NV AND WRN UT...WHERE THE LATEST DETERMINISTIC AND ENSEMBLE
MODEL GUIDANCE INDICATE STRONG WINDS COMBINING WITH RH AROUND 15-20
PERCENT AMIDST DRY FUELS. OTHERWISE...NO CHANGES HAVE BEEN MADE TO
THE ONGOING FORECAST. A CRITICAL AREA CONTINUES FOR PORTIONS OF ERN
WA AND THE ID PANHANDLE. EXPANSION OF THIS CRITICAL AREA...AND/OR
ADDITIONAL CRITICAL AREAS...MAY BE NEEDED IN SUBSEQUENT OUTLOOKS.
HOWEVER...THE LATEST MODEL GUIDANCE OFFERS LIMITED CONFIDENCE IN
SPATIOTEMPORAL ALIGNMENT OF CRITICALLY STRONG WINDS WITH CRITICALLY
LOW RH ON ANY MORE THAN A SHORT-DURATION...LOCALIZED BASIS AT THIS
TIME.

..COHEN.. 08/28/2015

.PREV DISCUSSION... /ISSUED 0452 AM CDT FRI AUG 28 2015/

...SYNOPSIS...
AN UPPER TROUGH WILL MOVE NEWD OVER THE PACIFIC NORTHWEST AND
BRITISH COLUMBIA ON D2/SAT. STRONG MID-LEVEL FLOW ASSOCIATED WITH
THIS FEATURE COMBINED WITH A FRONTAL PASSAGE WILL LIKELY RESULT IN
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ACROSS A LARGE PORTION
OF THE INTERIOR PACIFIC NORTHWEST...GREAT BASIN...NRN/CNTRL
ROCKIES...AND NRN/CNTRL HIGH PLAINS SAT AFTERNOON AND EVENING...
POTENTIALLY CONTINUING INTO THE OVERNIGHT HOURS.

...MUCH OF THE INTERIOR PACIFIC NORTHWEST...GREAT BASIN...NRN/CNTRL
ROCKIES...AND NRN/CNTRL HIGH PLAINS...
AS STRONG MID-LEVEL FLOW OF 50-75 KT ASSOCIATED WITH THE UPPER
TROUGH MOVES OVER THE PACIFIC NORTHWEST...A COLD FRONT IS LIKEWISE
FORECAST TO MOVE EWD OVER THIS AREA. LOW-LEVEL WINDS SHOULD SHIFT
FROM SLY IN THE MORNING TO SWLY/WLY IN THE AFTERNOON AND EVENING
BEHIND THE FRONT. SUSTAINED WIND SPEEDS IN THE LEE OF THE CASCADES
WILL LIKELY INCREASE TO 20-35 MPH...WITH HIGHER GUSTS UP TO 50 MPH
POSSIBLE. RH VALUES WILL PROBABLY DECREASE ONLY MARGINALLY WITH
FRONTAL PASSAGE ACROSS THE INTERIOR PACIFIC NORTHWEST. HOWEVER...
AFTER COORDINATION WITH THE FORECAST OFFICE IN SPOKANE...THE
EXPECTED STRENGTH OF THE WINDS COMBINED WITH ONGOING FIRES IN ERN WA
STRONGLY SUGGESTS THE INCLUSION A CRITICAL AREA IS PRUDENT FOR
PORTIONS OF ERN WA AND THE ID PANHANDLE...EVEN THOUGH CRITICAL RH
THRESHOLDS MAY NOT BE STRICTLY MET.

A MUCH LARGER ELEVATED AREA HAS BEEN DELINEATED FOR MOST OF THE
REMAINDER INTERIOR PACIFIC NORTHWEST AND PORTIONS OF THE GREAT
BASIN...NRN/CNTRL ROCKIES...AND NRN/CNTRL HIGH PLAINS...WHERE
STRONG/GUSTY WINDS AND RH VALUES APPROACHING CRITICAL LEVELS WILL
INCREASE FIRE WEATHER CONCERNS. ACROSS THESE REGIONS...FORECAST WIND
SPEEDS AND/OR RH VALUES DO NOT CURRENTLY EXCEED CRITICAL THRESHOLDS
ON A WIDESPREAD BASIS...ALTHOUGH DEPENDING ON FUTURE MODEL
GUIDANCE...ADDITIONAL CRITICAL AREAS MAY BE NEEDED IN LATER UPDATES.

FINALLY...AN ISOLATED DRY THUNDERSTORM AREA HAS BEEN INTRODUCED FOR
PORTIONS OF FAR NERN NV...NWRN UT...ID...FAR NWRN WY...AND MUCH OF
WRN/CNTRL MT. ACROSS THIS AREA...LARGE-SCALE ASCENT ASSOCIATED WITH
THE APPROACHING UPPER TROUGH AND TOPOGRAPHY SHOULD ENCOURAGE
ISOLATED TO PERHAPS WIDELY SCATTERED THUNDERSTORMS SAT AFTERNOON AND
EVENING. SOME OF THESE STORMS HAVE THE POTENTIAL TO BE DRY...WITH
PWAT VALUES FORECAST TO BE MAINLY IN THE 0.75-1.00 INCH RANGE. FAST
STORM MOTIONS AND DRY SUB-CLOUD LAYERS SHOULD LIMIT WETTING RAINFALL
AMOUNTS...AND ANY LIGHTNING STRIKES COULD ENCOURAGE NEW FIRE STARTS
IN THE PRESENCE OF DRY FUELS.

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



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