015
FXUS65 KBOI 171212
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
612 AM MDT FRI JUL 17 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- SHOWERS/THUNDERSTORMS TODAY, MAINLY ACROSS SOUTH-CENTRAL IDAHO
AND THE CENTRAL IDAHO MOUNTAINS. STORMS WILL BE CAPABLE OF HEAVY
RAINFALL WITH A LIMITED FLASH FLOOD RISK, GUSTY OUTFLOW WINDS
TO 60 MPH, AND SMALL HAIL.
- AREAS OF SMOKE ACROSS SOUTHEAST OREGON TODAY THROUGH THE
WEEKEND, POSSIBLY EXPANDING INTO SOUTHWEST IDAHO AT TIMES.
- HOT TEMPERATURES CONTINUE INTO NEXT WEEK, WITH VALLEY HIGHS
IN THE UPPER 90S TO AROUND 100 DEGREES.
- SHOWERS/THUNDERSTORMS DECREASE THIS WEEKEND, THEN INCREASE
NEXT WEEK WITH HEAVY RAINFALL POSSIBLE.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED 347 AM MDT FRI JUL 17 2026
AN UPPER LEVEL LOW ALONG THE COAST OF WASHINGTON AND AN UPPER
LEVEL RIDGE TO OUR EAST WILL RESULT IN SOUTHERLY FLOW ALOFT
ACROSS THE AREA. WHILE DRIER AIR WILL MOVE INTO SOUTHEAST
OREGON, MONSOONAL MOISTURE WILL INCREASE ACROSS IDAHO TODAY,
ESPECIALLY SOUTH-CENTRAL IDAHO INTO THE CENTRAL IDAHO MOUNTAINS
WHERE PRECIPITABLE WATER WILL CLIMB TO THE 95TH-99TH
PERCENTILE. ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP
ALONG A WEAK DISTURBANCE THIS MORNING ACROSS FAR EASTERN OREGON
AND WEST- CENTRAL IDAHO. THIS AFTERNOON, AIDED BY DAYTIME
HEATING, SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE ACROSS
THE CENTRAL IDAHO MOUNTAINS AND SOUTH-CENTRAL IDAHO.
THUNDERSTORMS WILL BE CAPABLE OF HEAVY RAINFALL, RESULTING IN A
LOCALIZED THREAT OF FLASH FLOODING, WITH THE BIGGEST RISK OVER
BURN SCARS AND STEEP TERRAIN. A FLASH FLOOD WATCH REMAINS IN
EFFECT FOR THE WAPITI BURN AREA THIS AFTERNOON AND EVENING.
THUNDERSTORMS WILL ALSO BE CAPABLE OF GUSTS 30-50 MPH WITH
ISOLATED UP TO 60 MPH AND SMALL HAIL.
THUNDERSTORMS WILL LIFT NORTHEAST OUT OF THE AREA THIS EVENING.
ON SATURDAY, THE FLOW ALOFT WILL BECOME SOUTHWESTERLY, AND BY
SUNDAY NEARLY WESTERLY AS THE UPPER LOW ALONG THE WASHINGTON
COAST MOVES ACROSS SOUTHWEST CANADA. THIS WILL PUSH MONSOONAL
MOISTURE TO THE EAST, DECREASING SHOWER AND THUNDERSTORM
CHANCES SATURDAY AND LIMITING COVERAGE TO THE EASTERNMOST ZONES.
BY SUNDAY, COVERAGE WILL BE LIMITED TO THE HIGHER TERRAIN
ACROSS SOUTH-CENTRAL IDAHO.
TEMPERATURES WILL REMAIN HOT THROUGH THE PERIOD, WITH LOWER
VALLEY HIGHS IN THE UPPER 90S TO AROUND 100 DEGREES. WINDS
OUTSIDE OF THUNDERSTORMS WILL BE TYPICAL WITH AFTERNOON BREEZES
DEVELOPING. FINALLY, SMOKE FROM FIRES PRIMARILY IN CENTRAL
OREGON HAS MOVED INTO SOUTHEAST OREGON, WITH IMPACTS LIKELY TO
CONTINUE THROUGH THE WEEKEND, ESPECIALLY AT NIGHT. SMOKE MAY
ALSO PUSH INTO SOUTHWEST IDAHO OVER THE WEEKEND, ALTHOUGH
CONFIDENCE IS LOWER.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED 347 AM MDT FRI JUL 17 2026
AS THE UPPER TROUGH OVER CANADA MOVES EAST, THE UPPER RIDGE
CENTERED OVER THE CENTRAL U.S. WILL EXPAND TO THE WEST AND
STRENGTHEN. THIS WILL ALLOW THE FLOW ALOFT TO BECOME SOUTHERLY,
TRANSPORTING MONSOONAL MOISTURE INTO THE AREA ONCE AGAIN.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INITIALLY BE FOCUSED
ACROSS SOUTHERN IDAHO ON MONDAY, WITH A GREATER THAN 15% CHANCE
OF SHOWERS/STORMS EXPANDING ACROSS THE HIGHER TERRAIN ON
TUESDAY. MOISTURE WILL CONTINUE TO SURGE INTO THE AREA WEDNESDAY
AND THURSDAY, WITH ENSEMBLE-MEAN PRECIPITABLE WATER ONCE AGAIN
RISING ABOVE THE 95TH PERCENTILE. THIS WILL BRING A 30-60%
CHANCE OF SHOWERS AND THUNDERSTORMS TO ALL AREAS BOTH DAYS.
DEVELOPMENT MAY BE AIDED BY SHORTWAVE IMPULSES AS HINTED AT BY
DETERMINISTIC MODELS. SHOWER/STORM CHANCES DECREASE SLIGHTLY ON
FRIDAY. DUE TO THE VERY MOIST AIRMASS, HEAVY RAIN WILL BE A
CONCERN AND ANY FLASH FLOOD THREATS WILL BE CLOSELY MONITORED
THROUGH THE WEEK. DESPITE THE MOISTURE, TEMPERATURES WILL REMAIN
HOT THROUGH THE PERIOD, GENERALLY A FEW DEGREES ABOVE NORMAL
THANKS TO THE RIDGE OVER THE AREA.
AVIATION /12Z FRIDAY THROUGH SATURDAY/
ISSUED 550 AM MDT FRI JUL 17 2026
MAINLY VFR. ISOLATED SHOWERS/THUNDERSTORMS THIS MORNING NEAR THE
ID/OR BORDER. ISOLATED TO SCATTERED/NUMEROUS SHOWERS AND
THUNDERSTORMS THIS AFTERNOON, MAINLY OVER SOUTH-CENTRAL/CENTRAL
ID. LOCALIZED MVFR/IFR AND MOUNTAIN OBSCURATION IN
THUNDERSTORMS. OUTFLOW GUSTS 30-50 KT FROM STORMS POSSIBLE. HIGH
DENSITY ALTITUDE DUE TO HEAT IN THE AFTERNOON. AREAS OF SMOKE
IN SE OREGON REDUCING VISIBILITY, ESPECIALLY NEAR KBNO. SURFACE
WINDS OUTSIDE OF STORMS: SE-SW 5-15 KT, BECOMING VARIABLE THIS
EVENING. WINDS ALOFT AT 10KFT MSL: S 10-20 KT.
KBOI...MAINLY VFR. A 30% CHANCE OF THUNDERSTORMS OVER THE
TERMINAL THIS MORNING, AND AGAIN THIS AFTERNOON AFTER 21Z.
THUNDERSTORMS CAPABLE OF GUSTS TO 30 KT AND BRIEF HEAVY RAIN.
HIGH DENSITY ALTITUDE DUE TO HEAT THIS AFTERNOON. SURFACE WINDS:
W-NW 5-10 KT.
WEEKEND OUTLOOK...MAINLY VFR. CHANCE OF SHOWERS/THUNDERSTORMS OVER
SOUTH-CENTRAL ID AND THE CENTRAL ID MTNS SATURDAY AFTERNOON,
THEN LIMITED TO SOUTH-CENTRAL ID SUNDAY AFTERNOON. MOUNTAIN
OBSCURATION FROM STORMS. HIGH DENSITY ALTITUDE DUE TO HEAT.
SURFACE WINDS OUTSIDE OF STORMS: SW-NW 5-15 KT, AFTERNOON GUSTS
15-25 KT.
BOI WATCHES/WARNINGS/ADVISORIES
ID... FLASH FLOOD WATCH FROM 1 PM MDT THIS AFTERNOON THROUGH THIS
EVENING FOR IDZ013.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....ST
SHORT TERM...ST
LONG TERM....ST
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