262
FXUS65 KBOI 191733
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1133 AM MDT WED AUG 19 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- HEAT ADVISORY THURSDAY AND FRIDAY FOR LOWER ELEVATIONS AS
TEMPERATURES PUSH ABOVE 100 DEGREES.
- INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS OVER HIGHER
TERRAIN FRIDAY AND SATURDAY.
- ABOVE NORMAL TEMPERATURES NEXT WEEK WITH A CHANCE OF
THUNDERSTORMS OVER THE MOUNTAINS OF SOUTHWEST IDAHO.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED 418 AM MDT WED AUG 19 2026
NEXT FEW DAYS WILL SEE HEAT BUILD OVER THE REGION AS THE DESERT
SW RIDGE EXPANDS NORTHWARD. GUIDANCE HAS EDGED HIGHER OVER THE
PAST 24H, PUSHING MORE LOWER ELEVATION SITES IN THE 98-104
DEGREE RANGE FOR THUR/FRI. CERTAINLY 850-700 THICKNESS VALUES
WOULD SUPPORT HOTTER TEMPERATURES THAN NBM HAS FOR THESE DAYS
SO HAVE TRENDED THE FORECAST HIGHS WARMER, ESPECIALLY ON FRIDAY
WHICH WILL BE THE HOTTEST DAY. RESULTING HIGHS AND OVERNIGHT
LOWS (THURSDAY NIGHT) SUPPORTED ISSUANCE OF A HEAT ADVISORY
THUR/FRI ACROSS THE SNAKE PLAIN AND WEISER BASIN. OTHERWISE
LOOKING AT DRY CONDITIONS ACROSS THE AREA TODAY. THE BUILDING
UPPER RIDGE WILL PUSH MONSOON MOISTURE BACK TO THE ID/NV BORDER
ON THURSDAY, THEN NORTHWARD THROUGH INTO W-CENTRAL IDAHO ON
FRIDAY, RESULTING IN A CHANCE OF THUNDERSTORMS EACH AFTERNOON.
PRECIPITATION CHANCES HAVE INCREASED TO 30-50% FOR FRIDAY/FRIDAY
NIGHT ACROSS THE WESTERN MAGIC VALLEY AND EASTERN BOISE MTNS.
THE INITIAL PUSH OF THUNDERSTORMS WILL LIKELY PRODUCE MORE WIND
THAN RAIN ON FRIDAY AS THE NEAR SURFACE LAYER IS FAIRLY DRY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED 418 AM MDT WED AUG 19 2026
AN UPPER TROUGH WILL ENTER THE PAC NW ON SATURDAY, TRACKING
NORTHEASTWARD INTO CANADA BY SUNDAY. GUSTY SOUTHWEST WINDS
DEVELOP ACROSS OPEN TERRAIN IN SE OREGON AND SW IDAHO SOUTH OF
THE SNAKE PLAIN ON SATURDAY BRINGING ELEVATED FIRE WEATHER
CONDITIONS. FORECAST TEMPERATURES HAVE CONTINUED TO EDGE WARMER
FOR SATURDAY AS GUIDANCE IS DELAYING A FRONTAL PASSAGE UNTIL
THE LATE AFTERNOON/EVENING. SEEING A GROWING NUMBER SOLUTIONS
KEEP LOWER ELEVATIONS IN THE UPPER 90S, WHICH IS WARMER THAN
THE CURRENT NBM. INCREASED MOISTURE ALOFT (PRECIPITABLE WATER
VALUES REACHING THE 80TH PERCENTILE) WILL SUPPORT A 20-50%
CHANCE OF AFTERNOON/EVENING THUNDERSTORMS OVER W-CENTRAL AND
S-CENTRAL ID AND THE MTNS OF BAKER COUNTY. GUSTY WINDS AND BRIEF
HEAVY RAIN COULD ACCOMPANY STORMS.
THE REMAINDER OF THE EXTENDED PERIOD WILL BE DEFINED BY THE
PERSISTENT FOUR CORNERS RIDGE WHICH WILL PLACE OUR REGION UNDER
SOUTHWEST FLOW. NEAR NORMAL TEMPERATURES SUNDAY, WILL BE ON THE
RISE NEXT WEEK AS THE RIDGE REBOUNDS. MOISTURE CIRCLING THE
RIDGE WILL KEEP A CHANCE OF AFTERNOON THUNDERSTORMS MOSTLY
ACROSS SW IDAHO ZONES.
AVIATION /18Z WEDNESDAY THROUGH THURSDAY/
ISSUED 1131 AM MDT WED AUG 19 2026
VFR UNDER MOSTLY CLEAR SKIES. AREAS OF WILDFIRE SMOKE ACROSS NE
OREGON THIS AFTERNOON. SURFACE WINDS: LESS THAN 10KT THROUGH
TONIGHT. WINDS ALOFT AT 10KFT MSL: S 10-15 KT.
KBOI...VFR UNDER MOSTLY CLEAR SKIES. LIGHT SURFACE WINDS
THROUGH WEDNESDAY.
BOI WATCHES/WARNINGS/ADVISORIES
ID...HEAT ADVISORY FROM NOON THURSDAY TO 9 PM MDT FRIDAY FOR IDZ012-
014-016-033.
OR...HEAT ADVISORY FROM NOON MDT /11 AM PDT/ THURSDAY TO 9 PM MDT
/8 PM PDT/ FRIDAY FOR ORZ064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....LC
SHORT TERM...DG
LONG TERM....DG
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