361
FXUS65 KBOI 251118
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
518 AM MDT MON MAY 25 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- GUSTY WINDS TODAY AHEAD OF A PACIFIC COLD FRONT, RESULTING IN
CRITICAL FIRE WEATHER CONDITIONS IN SOUTHEASTERN OREGON.
- SCATTERED SHOWERS/THUNDERSTORMS THIS AFTERNOON AND EVENING
WITH OUTFLOW GUSTS AS STRONG AS 55 MPH AND BLOWING DUST,
MAINLY OVER SOUTH-CENTRAL IDAHO.
- MUCH COOLER TUESDAY WITH GUSTY WEST/NORTHWEST WINDS AND CHANCE
OF SHOWERS AND THUNDERSTORMS. BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS WEDNESDAY THROUGH FRIDAY AND CONTINUED COOL.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED 314 AM MDT MON MAY 25 2026
TODAY WILL BE THE WARMEST DAY WITH HIGH TEMPS 10-15 DEGREES ABOVE
NORMAL. A STRONG PACIFIC COLD FRONT WILL PASS THROUGH EASTERN
OREGON OVERNIGHT AND INTO WESTERN IDAHO TUESDAY MORNING. THE
SUPPORTING DEEP, COLD UPPER LOW WILL TRACK SOUTHWARD DOWN THE WA
AND OR COASTS TODAY AND TONIGHT, INLAND INTO SW OREGON TUESDAY
MORNING, THEN GOING AS FAR SOUTH AS CENTRAL CALIF WEDNESDAY.
THE GENERALLY SOUTHWARD TRACK OF THIS LOW WILL LIMIT HOW FAR
EAST THE COLD FRONT MOVES ACROSS IDAHO, BUT MODELS CARRY IT
PAST TWF TUESDAY ALTHOUGH WEAKENING THERE. EASTERN OR WILL COOL
25 TO 30 DEGREES FROM TODAY BUT SOUTH-CENTRAL IDAHO WILL COOL
ONLY ABOUT 15 DEGREES. HOWEVER, BEFORE THE COLD FRONT COMES IN,
THUNDERSTORMS (15 TO 30 PERCENT AREAL COVERAGE) WILL DEVELOP IN
SOUTH-CENTRAL IDAHO THIS AFTERNOON, THEN SHIFT NORTHWARD INTO
CENTRAL ID THIS EVENING. THUNDERSTORMS MAY PRODUCE OUTFLOW WIND
GUSTS TO 50 MPH AND BLOWING DUST, BUT RAIN AMOUNTS ARE FORECAST
LESS THAN .10 INCH EVEN IN THE WETTEST STORMS. THE COLD FRONT
ITSELF WILL HAVE A BETTER ORGANIZED RAIN-BAND WHEN IT PASSES
THROUGH EASTERN OR OVERNIGHT BEFORE WEAKENING IN WESTERN ID
TUESDAY. HOWEVER, TUESDAY EVENING LOOKS WETTER WITH MORE
NUMEROUS SHOWERS AND 50-80 PERCENT POP (GREATER IN ID THAN OR)
AS MOISTURE SURGES NORTHWARD INTO OUR CWA. BY WEDNESDAY MORNING
THAT MOIST SURGE WILL BE IN CENTRAL ID, PIVOTING WESTWARD BACK
INTO OR DURING THE DAY WEDNESDAY VIA THE UPPER FLOW AROUND THE
MAIN UPPER LOW. BY WEDNESDAY AFTERNOON IT WILL BE IN SOUTHEAST
OR AND BECOMING EVEN WETTER AS MORE MOISTURE ENTERS THROUGH NV
AROUND THE UPPER LOW. ALTOGETHER, RAINFALL THROUGH WEDNESDAY
NIGHT SHOULD TOTAL .25 TO .50 INCH, HEAVIEST IN THE IDAHO
CENTRAL MOUNTAINS AND IN SOUTHERN HARNEY AND MALHEUR COUNTIES.
THE SNAKE BASIN WILL HAVE ONLY .05 TO .15 INCH, LEAST IN SOUTH-
CENTRAL ID, BUT SOUTH-CENTRAL ID CAN EXPECT THE STRONGEST
THUNDERSTORM OUTFLOW WINDS (UP TO 50 MPH).
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED 314 AM MDT MON MAY 25 2026
THE STRETCH OF ACTIVE WEATHER WILL CONTINUE THROUGHOUT MUCH OF
THE LONG-TERM PERIOD. THE UPPER-LEVEL LOW WILL REMAIN OVER THE
GREAT BASIN THROUGHOUT THE COMING WEEK. AS WE GET INTO
FRIDAY/SATURDAY, A TROUGH DIGGING DOWN THE COAST OF BRITISH
COLUMBIA WILL SEND THE FILLING GREAT BASIN LOW NORTHWARD OVER
OUR AREA AS A SHORTWAVE TROUGH. THE BEST CHANCE FOR WETTING
RAIN WILL COME OVER THAT SAME TIME FRAME.
WITH COLD AIR ALOFT, SUFFICIENT MID-LEVEL MOISTURE, AND AFTERNOON
DESTABILIZATION, THE THREAT OF THUNDERSTORMS WILL PERSIST THROUGH
THE END OF THE WEEK. WHILE EACH AFTERNOON WILL BE THE PREFERRED
TIMING FOR THUNDERSTORMS (ESPECIALLY IF WE GET DAYTIME CLEARING
IN CLOUD COVER), NOCTURNAL STORMS CAN'T BE RULED OUT.
TEMPERATURES THROUGH THE END OF THE WEEK WILL BE NEAR (LEANING
BELOW) NORMAL, WITH BREEZY WINDS EACH AFTERNOON. ENSEMBLE
GUIDANCE HAS THE LOW OUT OF OUR AREA COME EARLY NEXT WEEK WITH
BUILDING RIDGE CENTERED OVER THE HIGH PLAINS, THIS WILL SUPPORT
A WARMING TREND TO START NEXT WEEK.
AVIATION /12Z MONDAY THROUGH TUESDAY/
ISSUED 518 AM MDT MON MAY 25 2026
GENERALLY VFR. SCATTERED THUNDERSTORMS OVER SW IDAHO AND FAR NE
OREGON MON/PM. THUNDERSTORMS CAPABLE OF 30-50 KT OUTFLOWS AND
BLOWING DUST. SHOWERS INCREASING ACROSS E OREGON EARLY TUE/AM,
WITH CEILINGS LOWERING TO MVFR NEAR KBKE/KBNO. SURFACE WINDS
OUTSIDE OF STORMS: VARIABLE UP TO 12 KT THIS MORNING. THEN SE-
SW 10-20 KT WITH AFTERNOON GUSTS TO 15-35 KT. A COLD FRONT WILL
SWITCH WINDS TO BE W-NW 10-25 KT WITH GUSTS TO 20-40 KT,
STRONGEST NEAR KBKE/KONO. WINDS ALOFT AT 10KFT MSL: S-SW 10-25
KT.
KBOI...VFR. A 30% CHANCE OF THUNDERSTORMS AFFECTING THE TERMINAL
BETWEEN MON/20Z-TUE/00Z. THUNDERSTORMS WILL BE CAPABLE OF
OUTFLOWS TO 30-50 KT, LIGHTNING, AND AREAS OF BLOWING DUST.
SURFACE WINDS OUTSIDE OF STORMS: SE-S 8-12 KT. BECOMING NW 10-15
KT TONIGHT FOLLOWING A COLD FRONT.
FIRE WEATHER
HIGH TEMPERATURES WELL ABOVE SEASONAL NORMALS, MINIMUM RH 10-15%,
AND GUSTY WINDS 30-45 MPH PROMPTED ISSUANCE OF A FIRE WEATHER
WATCH IN SOUTHEAST OREGON FOR THIS AFTERNOON AND EVENING. A
PACIFIC COLD FRONT, EXPECTED LATE TONIGHT, WILL BRING GUSTY
PRE-FRONTAL SOUTHWEST WINDS WITHIN THE ALREADY WARM AND DRY
ENVIRONMENT. SCATTERED THUNDERSTORMS IN SOUTHWEST IDAHO THIS
AFTERNOON AND EVENING WILL BRING LIGHTNING AND OUTFLOW WIND
GUSTS AS STRONG AS 55 MPH. FIRE DANGER WILL INCREASE, WITH
WILDFIRES AND PRESCRIBED FIRES ALREADY PRESENT IN THE WESTERN
TWIN FALLS BLM, BOISE BLM/NF AND PAYETTE NF. MORNING RH WILL BE
SUBSTANTIALLY HIGHER WEDNESDAY THROUGH NEXT SUNDAY, AND THERE
WILL BE A 30-40% CHANCE OF WETTING RAIN EACH DAY AS THE MAIN
LOW PRESSURE SYSTEM ALOFT REMAINS RIGHT OVER THE DISTRICT.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...FIRE WEATHER WATCH FROM 2 PM PDT THIS AFTERNOON THROUGH THIS
EVENING FOR ORZ670-672.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....NF
SHORT TERM...LC
LONG TERM....NF
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