104
FXUS65 KBOI 211155
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
555 AM MDT THU MAY 21 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- DRY AND GRADUALLY WARMING THROUGH MEMORIAL DAY.
- MUCH COOLER WITH GUSTY WINDS AND A CHANCE OF
SHOWERS TUESDAY AND WEDNESDAY, WARMING THURSDAY.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED 310 AM MDT THU MAY 21 2026
NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST IN THE SHORT TERM,
I.E., CONTINUED DAY-TO-DAY WARMING THROUGH MONDAY (MEMORIAL DAY)
WHEN SOUTHWESTERLY FLOW ALOFT FULLY REPLACES THE CURRENT COOL
NORTHWESTERLY FLOW ALOFT. THIS AFTERNOON ALSO LOOKS WINDIER THAN
YESTERDAY IN THE SNAKE BASIN WITH GUSTS UP TO 35 MPH. SKIES
WILL BE MOSTLY CLEAR, WITH ONLY SCATTERED HIGH CLOUDS.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED 310 AM MDT THU MAY 21 2026
A STRONG PACIFIC COLD FRONT WILL PASS THROUGH OUR CWA TUESDAY
BRINGING GUSTY WINDS, RAPID COOLING, AND A CHANCE OF SHOWERS BUT
ONLY LIGHT AMOUNTS OF RAIN, GENERALLY .10 INCH OR LESS. THE COLD
FRONT LOOKS SLIGHTLY WEAKER THAN IT DID YESTERDAY, WITH THE
SUPPORTING UPPER LOW STILL PASSING RIGHT OVER OUR CWA BUT NOT
AS DEEP AS BEFORE. MODELS AGREEMENT HAS ALSO DECREASED SLIGHTLY
AND MAY PARTIALLY ACCOUNT FOR THE SLIGHT AVERAGE WEAKENING. IN
ANY CASE, TUESDAY AND WEDNESDAY SHOULD BE A FULL 20 DEGREES
COOLER THAN MONDAY, WITH A WARMING TREND STARTING AGAIN THURSDAY.
AVIATION /12Z THURSDAY THROUGH FRIDAY/
ISSUED 547 AM MDT THU MAY 21 2026
VFR, WITH SCT-BKN HIGH CLOUDS AFTER 20Z. SURFACE WINDS: NW
5-10 KT OVERNIGHT THROUGH MORNING. WEAK, DRY COLD FRONT THIS
AFTERNOON WITH NW WIND 10-15 KT, GUSTS TO 25 KT. WINDS ALOFT AT
10KFT: N AROUND 15 KT.
KBOI...VFR WITH MOSTLY CLEAR SKIES. SURFACE WINDS:
LIGHT/VARIABLE THROUGH 16Z THEN NW 10-15 KT WITH GUSTS 20-25 KT
FROM 18Z TO 22/02Z.
WEEKEND OUTLOOK...VFR. MOSTLY CLEAR. INCREASING WEST WIND
SUNDAY AFTERNOON.
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.....LC
SHORT TERM...LC
LONG TERM....LC
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