040
FXUS65 KBOI 052355
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
555 PM MDT TUE MAY 5 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- WINDY THIS AFTERNOON AND TONIGHT.
- ISOLATED AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS TODAY
OVER THE MOUNTAINS OF S IDAHO AND SE OREGON, OTHERWISE DRY.
- ABOVE NORMAL TEMPERATURES WILL CONTINUE, AS MUCH AS 15-20
DEGREES ABOVE NORMAL NEXT MONDAY AND TUESDAY.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED 207 PM MDT TUE MAY 5 2026
ISOLATED SHOWERS AND THUNDERSTORMS (15-25 PERCENT AREAL COVERAGE)
IN AND NEAR THE MAGIC VALLEY LATE THIS AFTERNOON AND EVENING AS
HI-RES MODELS SHOW A DISTINCT CONVERGENCE ZONE THERE, AND ENOUGH
LIFT TO GENERATE CLOUDS AND PCPN. MODELS DEPICT LARGE SCALE
NORTHERLY SURFACE WINDS ENTERING THE SNAKE BASIN THROUGH BOTH
OREGON AND MONTANA AND CONVERGING IN THE MAGIC VALLEY. THE
STRONGER PORTION FROM MONTANA WILL PUSH THE CONVERGENCE ZONE
WESTWARD OVERNIGHT AS A "BACK DOOR" COLD FRONT, ALL THE WAY PAST
BOISE BY SUNRISE. THE AIR FROM MONTANA IS VERY DRY, BUT TONIGHT
WILL BE TOO WINDY TO ALLOW FULL RADIATIONAL COOLING ONCE SKIES
CLEAR. WEDNESDAY LOOKS SUNNY, DRY, LESS WINDY, AND SLIGHTLY
COOLER THAN TODAY. WEDNESDAY NIGHT SHOULD BE CLEAR, DRY, AND
CALMER, BUT BY THEN THE NEXT WARMER AIR MASS WILL APPROACH FROM
THE WEST, OFFSETTING THE BETTER CONDITIONS FOR RADIATIONAL
COOLING. SO WEDNESDAY NIGHT SHOULD BE NO COOLER THAN TONIGHT.
THURSDAY LOOKS SUNNY AND 3 TO 6 DEGREES WARMER THAN WEDNESDAY,
AND THURSDAY NIGHT LOOKS CLEAR AND COOL.
LONG TERM /FRIDAY THROUGH TUESDAY/
ISSUED 207 PM MDT TUE MAY 5 2026
A BRIEF COOLDOWN WILL COMMENCE FRIDAY INTO SATURDAY AS A WEAK AND
DRY COLD FRONT MOVES THROUGH THE REGION. HOWEVER, THE HEAT WILL
BUILD EARLY NEXT WEEK IN ASSOCIATION WITH A STRONG AREA OF HIGH
PRESSURE ALOFT OVER THE WESTERN UNITED STATES. MONDAY IS CURRENTLY
FORECAST TO SEE THE HOTTEST TEMPERATURES OF THE YEAR SO FAR, PEAKING
AT 15 TO 20 DEGREES NORMAL. LATEST PROBABILITIES SUGGEST A 50-80%
CHANCE OF A HIGH TEMPERATURE ABOVE 90 DEGREES IN THE SNAKE PLAIN AND
OVER LOWER ELEVATIONS OF SOUTHEAST OREGON. TUESDAY WILL ALSO BE HOT,
THOUGH PERHAPS A FEW DEGREES COOLER THAN MONDAY. PRECIPITATION
CHANCES WILL BE NEAR ZERO THROUGHOUT THE PERIOD, WITH ONLY A SLIGHT
CHANCE OF SHOWERS ON SATURDAY IN THE CENTRAL IDAHO MOUNTAINS.
AVIATION /00Z WEDNESDAY THROUGH THURSDAY/
ISSUED 543 PM MDT TUE MAY 5 2026
VFR. LOCALIZED SMOKE NEAR FIRE ACTIVITY. ISOLATED SHOWERS AND
THUNDERSTORMS IN THE MAGIC VALLEY EARLY THIS EVENING. GUSTY
ERRATIC OUTFLOW WINDS POSSIBLE FROM STORMS. SURFACE WINDS:
N-NW 10-20 KT WITH GUSTS UP TO 30 KT THROUGH EARLY THIS EVENING,
DECREASING TO 5-15 KT LATE THIS EVENING. WINDS BECOMING E-SE
10-20 KT AROUND WED/06Z IN THE MAGIC VALLEY, SPREADING THROUGH
THE LOWER SNAKE PLAIN OVERNIGHT WITH SPEEDS DECREASING TO 5-15
KT. WINDS ALOFT AT 10KFT MSL: N 15-30 KT.
KBOI...VFR. SURFACE WINDS: NW 15-20 KT WITH GUSTS AROUND 30 KT
EARLY THIS EVENING, DECREASING TO 7-12 KT AFTER WED/03Z. BECOMING
SE 8-14 KT AFTER WED/09Z.
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.....ST
SHORT TERM...LC
LONG TERM....JR
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