508
FNUS21 KWNS 171619
FWDDY1
DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1118 AM CDT THU SEP 17 2026
VALID 171700Z - 181200Z
NO CHANGES WERE MADE TO THE ELEVATED RISK AREAS ACROSS THE GREAT
BASIN AND SOUTHERN PLAINS. PLEASE SEE PREVIOUS FORECAST DISCUSSION
FOR MORE DETAILS.
..CENTRAL IDAHO AND NORTHEASTERN OREGON
SCATTERED SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AN UPPER LOW
OVER NORTHERN CA AND ACCOMPANYING MID-LEVEL JET ARC ACROSS PORTIONS
OF SOUTH-CENTRAL OR INTO CENTRAL MOUNTAINS OF ID AND NORTHERN UT.
ADDITIONAL THUNDERSTORMS (SOME POTENTIALLY SEVERE ACROSS CENTRAL ID)
ARE EXPECTED THIS AFTERNOON AS MLCAPE RISES TO AS HIGH AS 1000 J/KG
UNDER DIFFLUENT FLOW ALOFT WITHIN THE JET EXIT REGION. ALTHOUGH MORE
CLOUD-TO-GROUND LIGHTNING AND A FEW IGNITIONS ARE EXPECTED TODAY,
ADDITIONAL SHOWERS/THUNDERSTORMS, COOLER TEMPERATURES AND HIGHER
RELATIVE HUMIDITY ARE FORECAST D2/FRIDAY AND D3/SATURDAY AS THE LOW
SHIFTS EASTWARD. THIS SHOULD LIMIT OVERALL HOLDOVER IGNITION
CONCERNS AMID MARGINAL FUELS.
..WILLIAMS.. 09/17/2026
PREV DISCUSSION
/ISSUED 1248 AM CDT THU SEP 17 2026/
..SYNOPSIS
EXPANDING HIGH PRESSURE OVER THE SOUTHEAST AND CENTRAL U.S WILL
CONTRIBUTE TO WIDESPREAD ABOVE NORMAL TEMPERATURES AND DRY
CONDITIONS TODAY. MEANWHILE, AN UPPER-LEVEL LOW WILL REMAIN CENTERED
OVER NORTHERN CALIFORNIA/SOUTHERN OREGON, SUSTAINING STRONG
SOUTHWESTERLY FLOW OVER THE GREAT BASIN.
..SOUTHERN PLAINS
STRONG SURFACE HEATING AND DEEP VERTICAL MIXING WILL CONTRIBUTE TO
15-25% RH VALUES AND SUSTAINED SOUTHERLY WINDS OF 10-15 MPH THIS
AFTERNOON. THESE METEOROLOGICAL CONDITIONS WILL OVERLAP AN
EXCEPTIONALLY DRY AND RECEPTIVE FUELSCAPE IN SOUTHWESTERN OKLAHOMA
AND ALONG THE RED RIVER VALLEY, SUPPORTING THE INTRODUCTION OF
ELEVATED HIGHLIGHTS.
..GREAT BASIN
SOUTH-SOUTHWESTERLY SUSTAINED SURFACE WINDS OF AROUND 15 MPH ARE
EXPECTED TO EVOLVE UNDER AN EXPANDING 50 KT MID-LEVEL JET THIS
AFTERNOON. A DRY AND WELL MIXED BOUNDARY LAYER WILL PROMOTE RH
VALUES OF AROUND 15% ACROSS CENTRAL/NORTHERN NV AND SOUTHERN ID.
CONSECUTIVE DAYS OF DRY AND WINDY CONDITIONS HAVE LED TO
INCREASINGLY MORE RECEPTIVE FUELS ACROSS THE REGION, MAINTAINING AN
ELEVATED FIRE WEATHER RISK.
..CENTRAL IDAHO AND NORTHEASTERN OREGON
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS
NORTHERN CALIFORNIA, OREGON, AND THE NORTHERN ROCKIES AS THE
UPPER-LEVEL LOW BEGINS TO PIVOT NORTHEASTWARD OUT OF NORTHERN CA.
THE PRIMARY DRIVER OF LIMITED RAINFALL WILL BE FAST
NORTH-NORTHEASTWARD STORM MOTIONS OF 30-40 MPH, PARTICULARLY ON THE
NOSE OF THE MID-LEVEL JET ACROSS THE CENTRAL ID MOUNTAINS; HOWEVER,
MARGINAL FUELS, AND SUBSEQUENT SHOWERS/THUNDERSTORMS ON DAY 2/FRIDAY
AND DAY 3/SATURDAY AS THE LOW TRANSITIONS INTO THE NORTHERN ROCKIES
SHOULD REDUCE HOLDOVER IGNITION CONCERNS.
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
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