051  
FXUS65 KBOI 211756  
AFDBOI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOISE ID  
1156 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 /18Z THURSDAY THROUGH FRIDAY/  
 
ISSUED 1153 AM MDT THU MAY 21 2026  
VFR, SCATTERED HIGH LEVEL CLOUDS POSSIBLE THIS EVENING. SURFACE  
WINDS: NW WIND 10-15 KT, GUSTS TO 25 KT, VARIABLE 5-10 KT  
TONIGHT. WINDS ALOFT AT 10KFT: N 10-20 KT.  
 
KBOI...VFR WITH MOSTLY CLEAR SKIES. SURFACE WINDS: NW 10-15 KT  
WITH GUSTS 20-25 KT THROUGH THE AFTERNOON, BECOMING S-SE UP TO  
10 KT TONIGHT.  
 
WEEKEND OUTLOOK...VFR. MOSTLY CLEAR. 5-15 KT SW-NW WINDS EACH  
AFTERNOON, LIGHTER AND MORE VARIABLE EACH MORNING.  
 
 
   
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.....JM  
SHORT TERM...LC  
LONG TERM....LC  
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