130
FXUS65 KBOI 211020
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
420 AM MDT FRI AUG 21 2026
KEY MESSAGES
- HEAT ADVISORY THROUGH FRIDAY IN THE TREASURE VALLEY, WESTERN
MAGIC VALLEY, AND UPPER WEISER RIVER VALLEY.
- MONSOON MOISTURE WILL BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS FRIDAY THROUGH TUESDAY.
- A COLD FRONT WILL BRING STRONG THUNDERSTORMS TO THE AREA ON
SATURDAY AFTERNOON AND EVENING.
- THUNDERSTORMS CAPABLE OF PRODUCING GUSTY OUTFLOW WINDS UP TO
50 MPH WITH AREAS OF BLOWING DUST.
SHORT TERM /THROUGH SUNDAY NIGHT/
A RIDGE WILL REMAIN OVER THE AREA WITH CONTINUED HOT CONDITIONS.
A TROUGH REMAINS OFF THE OR COAST, BRINGING SOUTHERLY FLOW TO
THE AREA OVER THE NEXT FEW DAYS. WINDS EACH AFTERNOON WILL BE
BREEZY SOUTH-SOUTHWEST AHEAD OF A COLD FRONT THAT ARRIVES LATE
SATURDAY. MONSOON MOISTURE WILL INCREASE TODAY TO THE 85 TO
90TH PERCENTILE THROUGH SATURDAY, WITH A 15-25 PERCENT CHANCE OF
SHOWERS AND THUNDERSTORMS. INCREASING CLOUDS LATE THIS
AFTERNOON, WHICH MAY LOWER TEMPERATURES A FEW DEGREES FROM THE
FORECAST. QUITE A BIT OF RANGE IN TEMPERATURES TODAY WITH THE
CLOUD COVER UNCERTAINTY, WITH A FEW MODELS SHOWING UP TO 105
ACROSS THE SNAKE PLAIN THIS AFTERNOON UNDER FULL SUN. A COLD
FRONT WILL ENHANCE SHEAR ALOFT FOR THE POSSIBILITY OF STRONG
ORGANIZED THUNDERSTORMS ON SATURDAY AFTERNOON AND EVENING. THE
FRONT WILL BRING DRIER AIR TO THE AREA ON SUNDAY WITH BREEZY
WESTERLY WINDS. TEMPERATURES WILL BE AROUND 10-15 DEGREES ABOVE
NORMAL FRIDAY, LOWERING TO NEAR NORMAL BY SUNDAY.
LONG TERM /MONDAY THROUGH FRIDAY/
SOUTHWEST FLOW CONTINUES IN THE LONG TERM WITH MONSOON MOISTURE
KEEPING A THREAT OF SHOWERS AND STORMS OVER SOUTHWEST ID. MODELS
SHOW A POTENT SHORTWAVE MOVING OVER THE AREA ON MONDAY
AFTERNOON WITH A 15 TO 25 PERCENT CHANCE OF SHOWERS AND STORMS
OVER SOUTHWEST ID. FORECAST MAY NEED TO BE ADJUSTED HIGHER IN
EASTERN OR FOR THIS SHORTWAVE. A TROUGH OFF THE PAC NW COAST
PUSHES THE MONSOON MOISTURE EAST ON TUESDAY WITH DRIER AIR,
BREEZY CONDITIONS AND SLIGHTLY COOLER TEMPERATURES TUESDAY
THROUGH FRIDAY. TEMPERATURES WILL AROUND 2-5 DEGREES ABOVE
NORMAL THROUGH THE PERIOD.
AVIATION /06Z FRIDAY THROUGH SATURDAY/
ISSUED 1226 AM MDT FRI AUG 21 2026
VFR, WITH INCREASING MID-HIGH CLOUDS FROM THE WEST. PATCHY WILDFIRE
SMOKE OVER EAST-CENTRAL OR AND WEST-CENTRAL ID MOUNTAINS OVERNIGHT
THROUGH MORNING. ISOLATED SHOWERS/THUNDERSTORMS FRIDAY EVENING
THROUGH SATURDAY MORNING. STORMS CAPABLE OF GUSTY OUTFLOWS 30-40 KT.
SURFACE WINDS: SW-NW 5-15 KT UNTIL 21/02Z THEN GENERALLY VARIABLE
AND DIURNAL LESS THAN 8 KT TONIGHT THROUGH FRIDAY MORNING. WINDS
ALOFT AT 10KFT MSL: SW 15-25 KT.
KBOI...VFR, WITH SCT-BKN HIGH CLOUDS. PATCHY WILDFIRE SMOKE MAY
SLIGHTLY OBSCURE FOOTHILLS OVERNIGHT THROUGH MORNING. ISOLATED
SHOWERS/THUNDERSTORMS FRIDAY EVENING, WITH A 15-20% CHANCE OVER
TERMINAL AFTER SAT/00Z. SURFACE WINDS: LIGHT AND DIURNAL UNDER 7 KT
THROUGH FRIDAY MORNING, BECOMING SW 6-11 KT IN THE
AFTERNOON/EVENING.
WEEKEND OUTLOOK...SCATTERED SHOWERS AND THUNDERSTORMS CONTINUING
SATURDAY. GUSTY OUTFLOW WINDS 30-45 KT AND LOCALLY HEAVY RAIN FROM
STORMS. DRIER SUNDAY. LOCAL REDUCTIONS IN VISIBILITY DUE TO WILDFIRE
SMOKE THROUGH THE WEEKEND. GUSTY SW WINDS SATURDAY ACROSS SE OREGON.
BREEZY W-NW WINDS ALL AREAS ON SUNDAY.
BOI WATCHES/WARNINGS/ADVISORIES
ID...HEAT ADVISORY UNTIL 9 PM MDT THIS EVENING FOR IDZ012-014-016-
033.
OR...HEAT ADVISORY UNTIL 9 PM MDT /8 PM PDT/ THIS EVENING FOR
ORZ064.
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR ORZ670>672.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...KA
LONG TERM....KA
AVIATION.....JY
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