948
FXUS65 KBOI 292001
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
201 PM MDT WED APR 29 2026
KEY MESSAGES
- ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS ON THURSDAY,
PRIMARILY OVER THE HIGHER TERRAIN OF SOUTHWEST IDAHO AND ALONG
THE NEVADA BORDER.
- GRADUAL WARMING THROUGH SATURDAY.
- 20% CHANCE OF AFTERNOON THUNDERSTORMS EARLY NEXT WEEK.
SHORT TERM /THROUGH FRIDAY NIGHT/
THE REGION REMAINS UNDER A BROAD AND RELATIVELY DRY CYCLONIC
FLOW TONIGHT AS AN UPPER LEVEL TROUGH CONTINUES TO SHIFT
EASTWARD INTO THE ROCKIES. THERE REMAINS ENOUGH MOISTURE AND
INSTABILITY FOR ISOLATED SHOWERS AND THUNDERSTORMS THIS EVENING.
SKIES WILL REMAIN MOSTLY CLEAR OVERNIGHT, THOUGH SOME LINGERING
MOISTURE IN THE NORTH MAY SUPPORT A FEW CLOUDS. LOW
TEMPERATURES WILL BE AROUND SEASONAL NORMALS.
ON THURSDAY, A WEAK SHORTWAVE IS PROGGED TO ROTATE THROUGH THE
BACKSIDE OF THE DEPARTING TROUGH. WHILE OVERALL MOISTURE IS
LIMITED, COLD AIR ALOFT COMBINED WITH DAYTIME HEATING WILL
CREATE ENOUGH INSTABILITY FOR ISOLATED SHOWERS AND A FEW
THUNDERSTORMS. THE BEST CHANCES FOR THIS ACTIVITY (15 TO 20
PERCENT) WILL BE FOCUSED OVER THE CENTRAL IDAHO MOUNTAINS AND
HIGHER TERRAIN NEAR THE NEVADA BORDER DURING THE AFTERNOON AND
EVENING HOURS. ANY STORMS THAT FORM WILL BE CAPABLE OF PRODUCING
SMALL HAIL AND BRIEF GUSTY WINDS. ELSEWHERE, EXPECT MOSTLY
SUNNY CONDITIONS WITH LIGHT WINDS.
BY FRIDAY, AN UPPER LEVEL RIDGE WILL BEGIN TO AMPLIFY OVER THE
GREAT BASIN, LEADING TO A MORE STABLE AND WARMER PATTERN. HIGH
TEMPERATURES ON FRIDAY WILL CLIMB INTO THE MID 70S FOR THE LOWER
ELEVATIONS, WHICH IS ROUGHLY 5 TO 8 DEGREES ABOVE LATE APRIL
AVERAGES. WINDS WILL GENERALLY REMAIN LIGHT AND FOLLOW DIURNAL
PATTERNS. MOSTLY CLEAR SKIES WILL PERSIST THROUGH FRIDAY NIGHT
AS THE RIDGE AXIS MOVES DIRECTLY OVERHEAD.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
A TREND TOWARDS WARMER CONDITIONS WILL CONTINUE INTO THIS
WEEKEND, WITH HIGHS EXPECTED TO RANGE BETWEEN 8 TO 12 DEGREES
ABOVE NORMAL. THIS TRANSLATES TO HIGH TEMPERATURES IN THE UPPER
70S TO NEAR 80 DEGREES FOR MANY LOWER ELEVATION LOCATIONS,
INCLUDING THE TREASURE VALLEY AND WESTERN MAGIC VALLEY. SATURDAY
AND SUNDAY WILL REMAIN DRY ACROSS THE AREA WITH RIDGING ALOFT.
HOWEVER, AN UPPER LEVEL CLOSED LOW WILL DEVELOP OFF THE
CALIFORNIA COAST ON SUNDAY AND THEN TRACK EASTWARD THROUGH
NEVADA ON MONDAY AND TUESDAY. THE LATEST FORECAST MODELS HAVE
TRENDED FURTHER SOUTH WITH THE CLOSED LOW AND INDICATE THAT AN
UPPER LEVEL RIDGE WILL BUILD NORTH OF THE CLOSED LOW. THE UPPER
LOW WILL STILL BE CLOSE ENOUGH FOR A CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE AREA ON MONDAY AND TUESDAY. CHANCE OF
THUNDERSTORMS WILL BE 10 TO 20 PERCENT ACROSS THE NORTHERN HALF
OF THE FORECAST AREA WITH A 20 TO 50 PERCENT CHANCE ACROSS THE
SOUTHERN HALF. MODEL ENSEMBLES INDICATE THAT THE UPPER LEVEL LOW
WILL MOVE EAST AWAY FROM THE AREA AND THAT THE UPPER LEVEL
RIDGE OVER THE PACIFIC NORTHWEST WILL BECOME MORE DOMINATE BY
WEDNESDAY LIKELY BRINGING DRY AND WARM CONDITIONS TO THE AREA.
AVIATION /18Z WEDNESDAY THROUGH THURSDAY/
ISSUED 1143 AM MDT WED APR 29 2026
VFR. ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON IN
CENTRAL IDAHO MOUNTAINS WITH A 30 PERCENT CHANCE SHOWERS
APPROACHING KMYL. SKIES CLEARING TONIGHT WITH LIGHT AND
VARIABLE WINDS LESS THAN 10 KTS. WINDS ALOFT AT 10KFT MSL: NW
AROUND 15 KTS.
KBOI...VFR. SCATTERED MID-LEVEL CLOUDS THIS AFTERNOON, BECOMING
CLEAR TONIGHT. SURFACE WINDS NW 5 TO 10 KTS THIS AFTERNOON,
BECOMING LIGHT SE AT LESS THAN 5 KTS TONIGHT.
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
SHORT TERM...JDS
LONG TERM....JB
AVIATION.....JB
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