732
FXUS65 KBOI 190938
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
338 AM MDT SUN JUL 19 2026
KEY MESSAGES
- ISOLATED SHOWERS AND THUNDERSTORMS ALONG THE IDAHO/NEVADA
BORDER TODAY.
- AREAS OF SMOKE IN SOUTHEAST OREGON, DRIFTING INTO SOUTHWEST
IDAHO THROUGH THE WEEK.
- HOT TEMPERATURES THIS WEEK, HOTTEST ON MONDAY.
- SHOWERS/THUNDERSTORMS INCREASE THROUGH MIDWEEK WITH HEAVY
RAINFALL POSSIBLE ESPECIALLY ON WEDNESDAY.
SHORT TERM /THROUGH TUESDAY NIGHT/
HOT AND MOSTLY DRY CONDITIONS ARE EXPECTED TODAY AS AN UPPER
LEVEL RIDGE REMAINS CENTERED OVER THE CENTRAL U.S. AN UPPER
LEVEL TROUGH MOVING ACROSS SOUTHERN CANADA WILL KEEP THE FLOW
ALOFT SOUTHWESTERLY AND WILL TRANSPORT DRIER AIR INTO THE
REGION. HOWEVER, A 20% CHANCE OF SHOWERS AND THUNDERSTORMS WILL
PERSIST ALONG THE IDAHO/NEVADA BORDER THIS AFTERNOON WITH LOWER
CHANCES ELSEWHERE. HIGHS TODAY WILL BE SIMILAR TO YESTERDAY, IN
THE UPPER 90S TO AROUND 100 DEGREES IN THE LOWER VALLEYS. SMOKE
FROM WILDFIRES MAINLY IN OREGON WILL PERSIST ACROSS SOUTHEAST
OREGON AND INCREASE ACROSS SOUTHWEST IDAHO TODAY. WINDS WILL
MOSTLY BE LIGHT FROM THE NORTHWEST, LOCALLY BREEZY IN THE
AFTERNOON AND EVENING.
ON MONDAY, THE RIDGE WILL BEGIN TO BUILD NORTH ALONG THE WEST
COAST, ALLOWING FOR A RETURN OF SOUTHERLY FLOW ALOFT. MONSOONAL
MOISTURE WILL REENTER THE AREA, AND A WEAK IMPULSE EARLY MONDAY
WILL GENERATE A 10-20% CHANCE OF SHOWERS ACROSS SOUTHEAST OREGON
AND THE WEST-CENTRAL IDAHO MOUNTAINS. TEMPERATURES WILL REACH
THEIR PEAK ON MONDAY BEFORE DEEPER MOISTURE RETURNS, WITH HIGHS
UP TO 103 DEGREES IN THE TREASURE VALLEY. A HEAT ADVISORY HAS
BEEN ISSUED FOR PORTIONS OF SOUTHWEST IDAHO AND SOUTHEAST
OREGON. WARM OVERNIGHT LOWS IN THE UPPER 60S TO LOWER 70S AT
LOWER ELEVATIONS WILL LIMIT OVERNIGHT RELIEF. SHOWER AND
THUNDERSTORM CHANCES WILL RISE TO 20-40% NEAR THE IDAHO/NEVADA
BORDER IN THE AFTERNOON/EVENING. NORTHWEST WINDS WILL BECOME
BREEZY LATE IN THE DAY WITH WIND GUSTS 15-30 MPH. ON TUESDAY,
INCREASING MOISTURE WILL COOL TEMPERATURES A COUPLE DEGREES, BUT
IT WILL STILL BE HOT. SHOWER AND THUNDERSTORM CHANCES WILL
INCREASE ACROSS THE HIGHER TERRAIN BUT REMAIN LIMITED OVER THE
LOWER ELEVATIONS. STORMS WILL BE CAPABLE OF GUSTY WINDS AND
BRIEF HEAVY RAIN. SMOKE WILL PERSIST ACROSS THE AREA MONDAY AND
TUESDAY.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
SHOWER AND THUNDERSTORM POTENTIAL WILL INCREASE ON WEDNESDAY AS
AN EMBEDDED SHORTWAVE TROUGH LIFTS NORTH THROUGH THE GREAT
BASIN. THIS FEATURE SHOULD PROVIDE ADDITIONAL LIFT FOR MORE
WIDESPREAD CONVECTION WITH A 20-60% CHANCE OF SHOWERS/STORMS
ACROSS ALL AREAS. DEEP MONSOONAL MOISTURE IN PLACE (PW AROUND
1.25 INCHES / ABOVE THE 95TH PERCENTILE) WILL CREATE A RISK OF
HEAVY RAIN AND FLASH FLOODING, ESPECIALLY OVER BURN SCARS AND
STEEP TERRAIN. STARTING THURSDAY, THE FLOW ALOFT WILL TURN
SOUTHWESTERLY AS AN UPPER TROUGH DEEPENS OFF THE PACIFIC
NORTHWEST COAST. THIS WILL GRADUALLY PUSH DEEPER MOISTURE TO THE
EAST WITH A DRYING TREND FROM THE WEST THROUGH THE END OF THE
WEEK. BY THE WEEKEND, ONLY MINIMAL CHANCES FOR PRECIPITATION
WILL PERSIST ACROSS EASTERN AREAS. SOUTHWEST FLOW WILL BRING
HOT, DRY, AND BREEZY CONDITIONS LATE WEEK INTO THE WEEKEND.
SMOKE WILL LIKELY CONTINUE TO IMPACT MUCH OF THE AREA THROUGH
THE END OF THE WEEK, ESPECIALLY ACROSS SOUTHEAST OREGON.
AVIATION /06Z SUNDAY THROUGH MONDAY/
ISSUED 1232 AM MDT SUN JUL 19 2026
GENERALLY VFR. WILDFIRE SMOKE IN E-OREGON EXPANDING INTO SW-IDAHO
OVERNIGHT IMPACTING VISIBILITY, WITH LOCALIZED MVFR/IFR CONDITIONS
IN E-OREGON. SMOKE MIXING OUT SUN/PM WITH IMPROVING VISIBILITY. HIGH
DENSITY ALTITUDE SUN/PM DUE TO HEAT. SURFACE WINDS: GENERALLY
VARIABLE UP TO 8 KT OVERNIGHT. EXCEPT NW 10-15 KT WITH GUSTS TO
AROUND 20 KT NEAR KONO. THEN W-NW 5-15 KT SUN/PM. WINDS ALOFT AT
10KFT MSL: VARIABLE 5-10 KT.
KBOI...VFR. INCREASING HAZE OVERNIGHT FROM WILDFIRE SMOKE. HIGH
DENSITY ALTITUDE SUN/PM DUE TO HEAT. SURFACE WINDS: LIGHT AND
VARIABLE OVERNIGHT. THEN NW 8-12 KT SUN/PM.
BOI WATCHES/WARNINGS/ADVISORIES
ID...HEAT ADVISORY FROM NOON TO 9 PM MDT MONDAY FOR IDZ012-014>016-
030-033.
OR...HEAT ADVISORY FROM NOON MDT /11 AM PDT/ TO 9 PM MDT /8 PM PDT/
MONDAY FOR ORZ063-064.
AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR ORZ061-062.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...ST
LONG TERM....ST
AVIATION.....NF
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