579
FXUS65 KBOI 162008
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
208 PM MDT SUN AUG 16 2026
KEY MESSAGES
- ISOLATED SHOWERS AND THUNDERSTORMS TODAY AND MONDAY FAVORING
HIGHER TERRAIN, WITH OUTFLOWS UP TO 40 MPH AND LOCAL DOWNPOURS.
- TEMPERATURES NEAR OR SLIGHTLY ABOVE NORMAL THROUGH MID-WEEK,
THEN FURTHER WARMING EXPECTED BY LATE WEEK.
- RETURN OF MONSOON MOISTURE FRIDAY INTO THE WEEKEND WILL
INCREASE SHOWER AND THUNDERSTORM CHANCES ONCE AGAIN.
SHORT TERM /THROUGH TUESDAY NIGHT/
AN UPPER LEVEL RIDGE CENTERED OVER THE INTERMOUNTAIN WEST WILL
MAINTAIN WARMER AND DRIER CONDITIONS ACROSS SOUTHEAST OREGON AND
SOUTHWEST IDAHO THROUGH THE SHORT TERM PERIOD UNDER
SOUTHWESTERLY FLOW ALOFT. MID-LEVEL MOISTURE STREAMING AROUND
THE WESTERN PERIPHERY OF THIS RIDGE WILL INTERACT WITH WEAK
INSTABILITY TODAY, GENERATING ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS. THE HIGHEST CONFIDENCE FOR STORM DEVELOPMENT
TODAY REMAINS FOCUSED OVER THE HIGHER TERRAIN OF SOUTHWEST
IDAHO, INCLUDING THE OWYHEE MOUNTAINS AND WEST CENTRAL
MOUNTAINS. WITH LOW LEVELS REMAINING QUITE DRY, MAIN THREATS
WITH TODAY'S STORMS WILL BE LOCALIZED GUSTY OUTFLOW WINDS UP TO
45 MPH AND BRIEF DRY LIGHTNING STRIKES.
A WEAK SHORTWAVE TROUGH IS SHOWN TO MOVE INLAND ACROSS THE
FORECAST AREA ON MONDAY BRINGING MID-LEVEL PACIFIC MOISTURE.
ALTHOUGH THIS MOISTURE IS NOT AS EXTENSIVE AS THE MONSOONAL
MOISTURE FROM THE PREVIOUS COUPLE OF DAYS, THE INCOMING DYNAMIC
SUPPORT, COMBINED WITH DAYTIME HEATING, SHOULD BE SUFFICIENT TO
SUPPORT ISOLATED THUNDERSTORM DEVELOPMENT ACROSS THE AREA MONDAY
AFTERNOON AND EVENING. GIVEN THE LIMITED LOW-LEVEL MOISTURE,
STORMS ARE LIKELY TO PRODUCE GUSTY OUTFLOW WINDS 35 TO 45 MPH,
ALONG WITH FREQUENT LIGHTNING AND LITTLE TO NO RAINFALL
INCREASING THE RISK FOR FURTHER FIRE STARTS.
ANOTHER TROUGH PASSAGE ON TUESDAY SHOULD BRIEFLY SUPPRESS THE
RIDGE FOR SLIGHTLY COOLER TEMPERATURES, THOUGH STILL ABOVE
NORMAL AND BREEZY CONDITIONS. COOLER AIR ALOFT AND LINGERING
MID-LEVEL MOISTURE WILL MAINTAIN A SLIGHT CHANCE OF AFTERNOON
MOUNTAIN THUNDERSTORMS, MAINLY OVER THE CENTRAL IDAHO MOUNTAINS,
BUT OVERALL COVERAGE WILL DECREASE COMPARED TO MONDAY.
TEMPERATURES THROUGHOUT THE SHORT TERM WILL REMAIN ROUGHLY 5
DEGREES ABOVE SEASONAL AVERAGES.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
AS THE DESERT SOUTHWEST UPPER-LEVEL RIDGE BUILDS WEDNESDAY,
TEMPERATURES WILL BE NEAR NORMAL UNDER DRY CONDITIONS. STARTING
THURSDAY, FLOW ALOFT WILL BE SHIFTING FROM SOUTHWESTERLY TO
SOUTHERLY AS A PACIFIC LOW PRESSURE SYSTEM MOVES CLOSER TO SHORE.
THIS WILL INCREASE PRECIPITATION CHANCES THURSDAY AND FURTHER
FRIDAY, PRIMARILY OVER HIGHER TERRAIN. TEMPERATURES WILL BECOME HOT
THURSDAY AND FRIDAY UNDER THIS PATTERN. LATE FRIDAY INTO THE
WEEKEND, THE TROUGH WILL MOVE ONSHORE AND THEN NORTHEAST ACROSS THE
PACIFIC NORTHWEST STATES. SHOWERS AND THUNDERSTORM CHANCES WILL
PERSEVERE AS THE TROUGH ENHANCES LARGE-SCALE LIFT AND CARRIES
MOISTURE. SEVERAL DEGREES OF COOLING WILL BE LIKELY FOR SATURDAY AND
SUNDAY.
AVIATION /18Z SUNDAY THROUGH MONDAY/
ISSUED 1120 AM MDT SUN AUG 16 2026
GENERALLY VFR. AREAS OF SMOKE REDUCING VISIBILITY IN E OREGON.
THIS AFTERNOON, ISOLATED SHOWERS/THUNDERSTORMS AROUND KBKE/KMYL
AND KTWF/KJER WITH GUSTS UP TO 35 KT. SURFACE WINDS: VARIABLE
UP TO 10 KT THROUGH MORNING, EXCEPT E-NE 10-20 KT FOR KJER/KTWF
AREA. WINDS BECOMING SW-NW 5-15 KT IN THE AFTERNOON. WINDS
ALOFT AT 10KFT: SW 5-20 KT.
KBOI...VFR. SURFACE WINDS: SE 5-12 KT THROUGH MORNING, BECOMING
NW-N 5-12 KT IN THE AFTERNOON.
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....CH
AVIATION.....CH
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