908
FNUS22 KWNS 181951
FWDDY2
DAY 2 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0250 PM CDT WED JUN 18 2025
VALID 191200Z - 201200Z
..CRITICAL FIRE WEATHER AREA FOR NORTHWESTERN NEVADA
..CRITICAL FIRE WEATHER AREA FOR PARTS OF EASTERN NEVADA
WESTERN
UTAH...AND FAR NORTHWESTERN ARIZONA...
..GREAT BASIN
PREVIOUS FORECAST (SEE BELOW) REMAINS LARGELY ON TRACK. A BROAD
UPPER-LEVEL TROUGH MOVING INTO THE WESTERN U.S. WILL SUPPORT AN
EXPANSIVE AREA OF DRY, SOUTHWEST FLOW OVER THE REGION THURSDAY.
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS WILL SUPPORT RAPID FIRE
SPREAD WITH DRY FUELS IN PLACE.
..SAN JOAQUIN VALLEY AND DIABLO MOUNTAINS
AN APPROACHING UPPER-LEVEL TROUGH AND ATTENDANT INCREASED MID-LEVEL
FLOW WILL SUPPORT DRY/DOWNSLOPE FLOW FROM THE DIABLO RANGE INTO THE
SAN JOAQUIN VALLEY. THE COMBINATION OF DRY FUELS, SUSTAINED WINDS OF
15 MPH (LOCALIZED 20-30 MPH IN FAVORED MOUNTAIN GAPS) AND RELATIVE
HUMIDITY IN THE 10-20 PERCENT RANGE WILL RESULT IN ELEVATED FIRE
WEATHER CONDITIONS THURSDAY.
..SOUTHEASTERN OREGON INTO CENTRAL IDAHO MOUNTAINS
THE UPPER-LEVEL TROUGH MOVING INTO THE PACIFIC NORTHWEST WILL BRING
A MORE SUPPORTIVE ENVIRONMENT FOR ISOLATED DRY THUNDERSTORM
DEVELOPMENT ACROSS SOUTHEASTERN OREGON THURSDAY AFTERNOON, WITH
ISOLATED SHOWERS/THUNDERSTORMS MOVING INTO THE CENTRAL IDAHO BY
THURSDAY EVENING. HOWEVER, FUEL RECEPTIVENESS TO NEW IGNITIONS IS
NOT IDEAL, WITH ERC VALUES AROUND THE 80TH PERCENTILE OR LESS ACROSS
THE AREA ALONG WITH RELATIVELY HIGH LIVE FUEL MOISTURE COMPONENT.
THUS, OPTED TO EXCLUDE ISOLATED DRY THUNDERSTORM HIGHLIGHTS FOR THIS
EVENT.
..WILLIAMS.. 06/18/2025
PREV DISCUSSION
/ISSUED 0150 AM CDT WED JUN 18 2025/
..SYNOPSIS
PRECEDING A LARGE-SCALE TROUGH OVER THE WEST COAST, MODERATE-STRONG
DEEP-LAYER SOUTHWESTERLY FLOW WILL OVERSPREAD CENTRAL CA INTO THE
GREAT BASIN THROUGH THE AFTERNOON. AS THIS OCCURS, THE SURFACE
PRESSURE GRADIENT WILL TIGHTEN ACROSS MUCH OF THE WEST -- PERIPHERAL
TO SURFACE LOWS EVOLVING OVER THE NORTHERN GREAT BASIN AND THE LOWER
CO RIVER VALLEY.
..GREAT BASIN
STRONG DIURNAL HEATING AMID A DRY ANTECEDENT AIR MASS WILL RESULT IN
A DEEPLY MIXED BOUNDARY LAYER ACROSS MUCH OF THE GREAT BASIN --
CHARACTERIZED BY WIDESPREAD SURFACE TEMPERATURES IN THE 90S TO 100 F
AND SINGLE-DIGIT RH. AT THE SAME TIME, THE DEEP BOUNDARY-LAYER
MIXING INTO THE STRONG FLOW ALOFT, COUPLED WITH A TIGHTENING
PRESSURE GRADIENT, WILL YIELD AN EXPANSIVE AREA OF 25 MPH SUSTAINED
SOUTHWESTERLY SURFACE WINDS (WITH HIGHER GUSTS). OVER PORTIONS OF
NORTHWEST NV AND EASTERN NV/WESTERN UT, THESE HOT, DRY, AND WINDY
CONDITIONS OVER RECEPTIVE FUELS WILL LEAD TO CRITICAL FIRE-WEATHER
CONDITIONS.
..SAN JOAQUIN VALLEY AND ADJACENT AREAS
THE TIGHTENING PRESSURE GRADIENT AND BOUNDARY-LAYER MIXING INTO THE
ENHANCED FLOW ALOFT WILL FAVOR DRY/BREEZY CONDITIONS IN THE SAN
JOAQUIN VALLEY AND ADJACENT AREAS DURING THE AFTERNOON -- WHERE
ELEVATED FIRE-WEATHER CONDITIONS ARE EXPECTED OVER ANY DRY/RECEPTIVE
FUELS.
..PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT
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