646
FXUS65 KBOI 270010
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
610 PM MDT TUE MAY 26 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- STRONG THUNDERSTORMS CAPABLE OF WIND GUSTS TO 60 MPH POSSIBLE
OVER THE WEST CENTRAL AND BOISE MOUNTAINS, AND THE MAGIC
VALLEY TODAY.
- BREEZY NORTHWEST WINDS 30 TO 40 MPH THROUGH I-84 CORRIDOR
BETWEEN BAKER CITY AND MOUNTAIN HOME TODAY.
- ADDITIONAL SHOWERS AND THUNDERSTORMS AND PERIODS OF GUSTY
WINDS WEDNESDAY THROUGH SUNDAY.
- THUNDERSTORMS MAY PRODUCE GUSTY WINDS 40-60 MPH AND BLOWING
DUST, BRIEF HEAVY RAIN, AND HAIL THIS WEEK.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED 254 PM MDT TUE MAY 26 2026
A TROUGH REMAINS OVER NORTHERN CA AND WESTERN NV THIS AFTERNOON.
COOLER AIR ASSOCIATED WITH THE TROUGH IS FUNNELING COOL AIR DOWN
THE SNAKE BASIN AND I-84 CORRIDOR FROM BAKER CITY TO MOUNTAIN
HOME. A CONVERGENCE ZONE IS SETTING UP OVER THE MAGIC VALLEY
TODAY, WITH EASTERLY SURFACE WINDS. THIS BOUNDARY WILL BE THE
FOCUS SHOWERS AND THUNDERSTORM DEVELOPMENT OVER THE MAGIC VALLEY
AND CENTRAL ID MOUNTAINS THIS AFTERNOON. STORMS WILL TRACK
NORTH AND THEN TOWARD THE NORTHWEST OVER THE CENTRAL ID
MOUNTAINS THIS AFTERNOON AND EVENING. THUNDERSTORMS WILL BE
CAPABLE OF WIND GUSTS UP TO 50-60 MPH THIS EVENING OVER THE
CENTRAL ID MOUNTAINS AND MAGIC VALLEY. THUNDERSTORMS WILL
DIMINISH AFTER SUNSET THIS EVENING WITH SHOWERS CONTINUING IN
SOUTHEAST OR. THE UPPER LEVEL TROUGH WILL RETROGRADE FROM
CENTRAL NV TO NEAR RENO ON WEDNESDAY. WARMER TEMPERATURES
EXPECTED ON WEDNESDAY WITH EASTERLY FLOW SETTING UP OVER THE
AREA. SCATTERED SHOWERS AND THUNDERSTORMS FORM DURING THE
AFTERNOON ON WEDNESDAY WITH EASTERLY STORM MOTION. THE BEST
CHANCES FOR STORMS WILL BE OVER EASTERN OR AND THE CENTRAL ID
MOUNTAINS AGAIN. UNSTABLE CONDITIONS EXPECTED WEDNESDAY
AFTERNOON WITH GUSTY EAST TO SOUTHEAST WINDS DURING THE
AFTERNOON WITH GUSTS OF 20-40 MPH. THE TROUGH DOES NOT MOVE MUCH
ON THURSDAY WITH SHOWERS AND THUNDERSTORMS FORMING AGAIN DURING
THE AFTERNOON WITH PEAK HEATING IN THE SAME PLACES.
LONG TERM /FRIDAY THROUGH TUESDAY/
ISSUED 254 PM MDT TUE MAY 26 2026
ACTIVE WEATHER WILL CONTINUE ON FRIDAY, AS THE CLOSED UPPER LOW
HANGING OVER THE GREAT BASIN WILL SLOWLY MERGE WITH AN INCOMING
LONGWAVE TROUGH DIGGING FROM OFF THE COAST OF BRITISH COLUMBIA.
THIS PATTERN WILL CONTINUE WIDESPREAD SHOWERS AND THUNDERSTORMS
ON FRIDAY. THE MERGED TROUGH SYSTEM WILL THEN SWING NORTHWARD
OVER OUR AREA ON SATURDAY. LONG-RANGE GUIDANCE MOSTLY FAVORS
SHOWERS/THUNDERSTORMS OVER HIGHER TERRAIN ON SATURDAY. A COOLING
TREND BRINGING TEMPERATURES 5 TO 10 DEGREES BELOW NORMAL WILL
BE EXPECTED FRIDAY THROUGH SATURDAY.
THERE IS GENERAL GUIDANCE AGREEMENT ON A WEAKER AND DRIER
SHORTWAVE STEERING OVER THE AREA ON SUNDAY. CONSIDERABLE
UNCERTAINTY REMAINS OVER THE PRECIPITATION INTENSITY AND PATTERN
THIS SYSTEM WILL BRING; FOR NOW, A 20-40% CHANCE OF
SHOWERS/THUNDERSTORMS ARE FORECASTED FOR THE MOUNTAINS SUNDAY.
BY EARLY MONDAY, A BUILDING RIDGE WILL SUPPORT A WARMING TREND
TO START NEXT WEEK, LIKELY RETURNING TEMPERATURES UP TO 10
DEGREES ABOVE NORMAL ON TUESDAY.
AVIATION /00Z WEDNESDAY THROUGH THURSDAY/
ISSUED 607 PM MDT TUE MAY 26 2026
GENERALLY VFR. NUMEROUS SHOWERS THROUGH EARLY WED. SCATTERED
THUNDERSTORMS ACROSS NORTHEAST OR AND SOUTHWEST/CENTRAL ID
THROUGH TONIGHT, WITH STRONGEST STORMS OVER CENTRAL ID/BOISE
MTNS. STORMS CAPABLE OF OUTFLOWS TO 25-40 KT, SMALL HAIL, AND
HEAVY DOWNPOURS WITH REDUCED VIS. PERIODS OF MVFR CEILINGS
AROUND KBNO-KBKE-KMYL. SCATTERED SHOWERS AND THUNDERSTORMS
RETURN WED AFTERNOON.
SURFACE WINDS OUTSIDE OF STORMS: NW-N 10-20 KT WITH GUSTS 20-35
KT, BECOMING VARIABLE 5-15 KT OVERNIGHT. THEN, NE-SE 10-25 KT
WITH GUSTS 20-40 KT BEGINNING LATE WED AM. WINDS ALOFT AT 10KFT
MSL: TRANSITIONING TO E-SE 20-35 KT THIS EVENING.
KBOI...VFR. SCATTERED SHOWERS BEFORE WED/06Z. LIGHTNING THREAT
UNTIL SUNSET. A 20% CHANCE OF SHOWERS/THUNDERSTORMS RETURNING
TO UPPER TREASURE VALLEY WED/20Z-THU/00Z. STORMS IN AREA WILL BE
CAPABLE OF OUTFLOW WINDS TO 30-45 KT, ALONG WITH BRIEF
DOWNPOURS AND SMALL HAIL. SURFACE WINDS: NW 10-20 KT WITH GUSTS
TO 25-30 KT THROUGH EVENING. BECOMING VARIABLE 3-7 KT BY WED/06Z.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....SH
SHORT TERM...KA
LONG TERM....JY
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