Fire Weather Outlook Discussion
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FNUS22 KWNS 031604
FWDDY2

DAY 2 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1103 AM CDT MON AUG 03 2015

VALID 041200Z - 051200Z

ONLY MINOR CHANGES TO ONGOING FORECAST.  LATEST MODEL FORECAST
GUIDANCE SUGGESTS NEAR-CRITICAL FIRE WEATHER CONDITIONS IN LOCALIZED
AREAS ALONG THE COLUMBIA GORGE DUE TO DRY AFTERNOON CONDITIONS AND
WESTERLY WIND FLOW APPROACHING 20 MPH.  PARTS OF THIS REGION WILL BE
MONITORED IN LATER FORECASTS FOR A POSSIBLE UPGRADE IF GREATER
CERTAINTY OF WIND SPEEDS EXCEEDING 20 MPH IS REALIZED.

ELSEWHERE...INCREASING LARGE-SCALE ASCENT DUE TO AN APPROACHING
UPPER TROUGH AND INSOLATION/INSTABILITY WILL RESULT IN A LARGE AREA
OF THUNDERSTORMS ACROSS THE NORTHERN ROCKIES AND INTERIOR PACIFIC
NORTHWEST.  A MIX OF WET AND DRY STORMS ARE LIKELY...ALTHOUGH THE
THREAT FOR DRY THUNDERSTORMS SHOULD BE GREATER GIVEN SLIGHTLY LOWER
PRECIPITABLE WATER VALUES /AROUND 0.75 INCH/ AND ENHANCED MID-LEVEL
FLOW LEADING TO FASTER INDIVIDUAL STORM MOTIONS.  THE ISOLATED DRY
THUNDER AREA WAS EXPANDED SLIGHTLY SOUTH AND EAST FOR THIS UPDATE TO
INCLUDE MORE OF EASTERN IDAHO AND ADJACENT SOUTHWESTERN
MONTANA/NORTHEASTERN NEVADA.

..COOK.. 08/03/2015

.PREV DISCUSSION... /ISSUED 0400 AM CDT MON AUG 03 2015/

...SYNOPSIS...
A WEAKENING UPPER TROUGH OVER THE NRN ROCKIES/INTERMOUNTAIN WEST AT
THE START OF THE PERIOD WILL MOVE EWD INTO THE PLAINS DURING THE
DAY...AS A DEEP UPPER TROUGH CENTERED OVER BRITISH COLUMBIA
CONTINUES BUILDING INTO THE PACIFIC NORTHWEST. A SHORTWAVE TROUGH
OVER THE ERN PACIFIC IS EXPECTED TO EJECT NEWD INTO CNTRL/NRN CA AS
IT BEGINS TO FEEL THE INFLUENCE OF THE DEEP TROUGH TO THE
NORTH...WHILE AN UPPER RIDGE CONTINUES TO REBUILD OVER THE DESERT
SOUTHWEST.

...NRN CA/SRN ORE NEWD INTO WRN MT...
LARGE-SCALE ASCENT /FROM A COMBINATION OF THE DEEP TROUGH OVER BC
AND THE SHORTWAVE MOVING INTO CNTRL/NRN CA/ AND LINGERING
INSTABILITY WILL AGAIN SUPPORT A THREAT OF ISOLATED TO WIDELY
SCATTERED TSTMS FROM NRN CA/SRN ORE NEWD INTO WRN MT. WHILE SOME
LOW-LEVEL COOLING IS EXPECTED...DECREASING THE POTENTIAL FOR
EVAPORATION...SOME DRYING IS ALSO EXPECTED IN THE WAKE OF THE TROUGH
MOVING INTO THE PLAINS...RESULTING IN PW VALUES GENERALLY IN THE 0.5
- 0.75 INCH RANGE. THIS WILL SUPPORT A MIX OF WET/DRY TSTM MODES
THAT WILL POSE A RISK OF IGNITION GIVEN THE PRESENCE OF VERY DRY
FUELS.

...COLUMBIA RIVER BASIN EWD INTO NRN ID PANHANDLE/NWRN MT...
MODESTLY ENHANCED LOW-LEVEL WLY FLOW AND RH VALUES IN THE 10-20
PERCENT RANGE WILL AGAIN SUPPORT A THREAT OF ELEVATED FIRE WEATHER
CONDITIONS ACROSS THE ERN SLOPES OF THE CASCADES INTO PORTIONS OF
THE COLUMBIA RIVER VALLEY. THERE IS SOME POTENTIAL FOR ELEVATED
CONDITIONS TO EXTEND EWD INTO NWRN MT...BUT GIVEN UNCERTAINTY
REGARDING THE STRENGTH OF LOW-LEVEL FLOW WITH ERN EXTENT...THE
ELEVATED DELINEATION HAS BEEN CONFINED TO THE COLUMBIA RIVER BASIN
AREA.

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




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