127
FXUS65 KBOI 252345
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
545 PM MDT THU JUN 25 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- A SIGNIFICANT PATTERN CHANGE ARRIVES FRIDAY AS A COOL UPPER
LEVEL TROUGH PUSHES A COLD FRONT THROUGH, BRINGING WIDESPREAD
SHOWERS, SCATTERED THUNDERSTORMS AND COOLER TEMPERATURES.
- SCATTERED THUNDERSTORMS FRIDAY AFTERNOON INTO EARLY SATURDAY
COULD PRODUCE STRONG OUTFLOW WINDS, SMALL HAIL AND BRIEF HEAVY
RAIN.
- TEMPERATURES AROUND 15 TO 20 DEGREES BELOW NORMAL SATURDAY AND
SUNDAY.
- SIGNIFICANT PRECIPITATION AND LIGHT SNOW ABOVE 7000 FEET POSSIBLE
SATURDAY THROUGH SUNDAY.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED 218 PM MDT THU JUN 25 2026
AN UPPER LEVEL LOW AND COLD FRONT MOVING INTO THE REGION EARLY
FRIDAY MORNING WILL BEGIN A SIGNIFICANT PATTERN SHIFT. THE COLD
FRONT WILL CROSS THE AREA FRIDAY MORNING, BRINGING LIGHT SHOWERS
AND GUSTY WINDS. PARTIAL CLEARING BEHIND THE FRONT IN THE
AFTERNOON WILL ALLOW FOR THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS. STORMS ARE EXPECTED TO INITIATE ACROSS SOUTHEAST
OREGON AROUND NOONTIME, THEN TRACK EASTWARD INTO SOUTHWEST IDAHO
LATE FRIDAY AFTERNOON AND EARLY EVENING.
DESPITE INCREASING MOISTURE ALOFT, LOW LEVELS WILL REMAIN QUITE
DRY THROUGH AT LEAST EARLY FRIDAY EVENING, INCREASING THE RISK
FOR STRONG, ERRATIC OUTFLOW WINDS FROM ANY STORMS. THE LOWER
LEVELS WILL EVENTUALLY MOISTEN UP OVERNIGHT, WITH STORMS
TRANSITIONING TO A THREAT FOR BRIEF HEAVY RAIN AND SMALL HAIL.
THIS HEAVY RAIN THREAT WILL BE MOST PRONOUNCED BY SATURDAY
MORNING AS THE BULK OF THE CONVECTIVE ACTIVITY SHIFTS INTO
SOUTHWEST IDAHO. THE UPPER LEVEL TROUGH WILL PROVIDE AMPLE
DYNAMIC SUPPORT TO KEEP THUNDERSTORMS GOING OVERNIGHT FRIDAY
INTO SATURDAY.
AS THE CENTER OF THE LOW MOVES INTO THE REGION ON SATURDAY,
SHOWER AND THUNDERSTORM ACTIVITY WILL FOCUS HEAVILY ACROSS
SOUTHWEST IDAHO. PRECIPITABLE WATER (PW) VALUES ARE PROGGED TO
PEAK AROUND THE 90TH PERCENTILE SATURDAY MORNING, SUPPORTING
STORMS CAPABLE OF PRODUCING BRIEF HEAVY RAIN THROUGH SATURDAY
EVENING. PRECIPITATION AMOUNTS OF UP TO 1 TO 1.25 INCHES ARE
POSSIBLE OVER THE CENTRAL IDAHO MOUNTAINS. LESSER AMOUNTS ARE
EXPECTED IN EASTERN OREGON, WHERE 0.25 TO 0.50 INCHES IS
FORECAST, WHILE THE SNAKE RIVER PLAIN WILL GENERALLY SEE BETWEEN
0.25 AND 0.50 INCHES.TEMPERATURES WILL PLUMMET TO AROUND 20
DEGREES BELOW NORMAL ON SATURDAY. SEVERAL LOCATIONS ARE FORECAST
TO APPROACH RECORD LOW MAXIMUM TEMPERATURES FOR THE DAY.
PRECIPITATION AND THUNDERSTORM ACTIVITY WILL GRADUALLY TAPER OFF
FROM WEST TO EAST LATE SATURDAY NIGHT AS THE CORE OF THE TROUGH
MOVES INTO THE GREAT BASIN.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED 218 PM MDT THU JUN 25 2026
A LOW PRESSURE SYSTEM OVER THE NORTHERN ROCKIES WILL CONTINUE
TO BRING COOL AND SHOWERY CONDITIONS TO THE FORECAST AREA ON
SUNDAY, ESPECIALLY FOR WEST-CENTRAL/CENTRAL IDAHO. SNOW LEVELS
WILL TEMPORARILY LOWER TO 6500-7500 FT MSL SUN MORNING, ALLOWING
LIGHT SNOW TO FALL ACROSS THE HIGH TERRAIN. GUSTY WINDS WILL
DEVELOP IN THE AFTERNOON, WHILE TEMPERATURES REMAIN 15-20
DEGREES BELOW NORMAL. A SLIGHT CHANCE OF THUNDERSTORMS IS ALSO
FORECAST FOR SUNDAY AFTERNOON, ONCE AGAIN FAVORING CENTRAL
IDAHO. CONDITIONS WILL TREND A LITTLE WARMER ON MONDAY AS THE
LOW GRADUALLY DEPARTS TOWARD THE NORTHEASTWARD. HOWEVER,
UNSETTLED CONDITIONS WILL LINGER ACROSS THE NORTHWEST THROUGH
WEDNESDAY AS A SECONDARY LOW APPROACHES FROM BC CANADA. THIS
WILL KEEP TEMPERATURES BELOW NORMAL THROUGH AT LEAST WEDNESDAY.
AVIATION /00Z FRIDAY THROUGH SATURDAY/
ISSUED 545 PM MDT THU JUN 25 2026
INCREASING CLOUDS, WITH VIRGA AND SHOWERS DEVELOPING LATE DUE
TO COLD FRONT APPROACHING FROM THE WEST. SHOWERS CONTINUING INTO
FRIDAY AM, THEN WIDELY SCATTERED SHOWERS/THUNDERSTORMS FRIDAY
PM. STORMS CAPABLE OF OUTFLOWS TO 30-45 KT, SMALL HAIL, BRIEF
HEAVY RAIN. MVFR/IFR POSSIBLE IN HEAVY RAIN, ESP OVER MTNS. MTNS
OBSCURED IN PRECIP. SURFACE WINDS OUTSIDE OF STORMS: NW 10-20
KT TONIGHT, WITH GUSTS TO 20-35 KT FOLLOWING FRONTAL PASSAGE
AND IN VIRGA/SHOWERS. THEN VARIABLE 5-15 KT FRI/PM WINDS ALOFT
AT 10KFT MSL: W-SW 10-30 KT.
KBOI...VFR. VIRGA AND VICINITY SHOWERS LATE TONIGHT, THEN
FREQUENT RAIN SHOWERS BEGIN APPROX FRI/13Z WITH COLD FRONT.
THUNDERSTORM CHANCES INCREASE (30%) FRIDAY AFTERNOON.
THUNDERSTORMS CAPABLE OF OUTFLOWS TO 30-45 KT, SMALL HAIL, BRIEF
HEAVY RAIN. SURFACE WINDS: W-N 5-15 KT, GUSTS AROUND 25 KT WITH
VIRGA/SHOWERS/COLD FRONT OVERNIGHT THROUGH FRI MORNING.
WEEKEND OUTLOOK...SHOWERS AND THUNDERSTORMS SATURDAY AND
SUNDAY. BRIEF MVFR/IFR POSSIBLE IN HEAVY RAIN OR SNOW, ESP OVER
MTNS. MOUNTAINS OBSCURED. SNOW LEVELS TEMPORARILY LOWERING TO
6500-7500FT MSL SUNDAY MORNING. GUSTY WEST-NORTHWEST SURFACE
WINDS DURING THE AFTERNOONS.
BOI WATCHES/WARNINGS/ADVISORIES
ID...RED FLAG WARNING FROM NOON FRIDAY TO 6 AM MDT SATURDAY FOR
IDZ400-420-423-424-426.
OR...RED FLAG WARNING FROM NOON MDT /11 AM PDT/ FRIDAY TO 6 AM MDT
/5 AM PDT/ SATURDAY FOR ORZ670>674.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....NF
SHORT TERM...JDS
LONG TERM....SH
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