352
FXUS65 KGGW 062046
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
246 PM MDT MON JUL 6 2026
KEY MESSAGES
- WIDESPREAD THUNDERSTORMS BEGINNING LATE TONIGHT AND CONTINUING
THROUGH TUESDAY NIGHT. ISOLATED SEVERE STORMS ARE POSSIBLE BUT
HEAVY FOCUSED RAINFALL IS THE MAIN CONCERN.
- UNSETTLED WEATHER WILL LIKELY CONTINUE THROUGH THURSDAY.
- EXPECT HIGHS TO BEGIN REACHING THE 90S FRIDAY THROUGH THE
WEEKEND WITH ISOLATED TIPPLE DIGITS POSSIBLE SATURDAY.
DISCUSSION
WEATHER PATTERN OVERVIEW:
TONIGHT: A VERY AGGRESSIVE SHORTWAVE WILL APPROACH ALONG A
GRADUALLY SLOPED WARM FRONT ON SOUTHWEST FLOW ALOFT BEGINNING JUST
BEFORE MIDNIGHT TONIGHT. THIS WILL PROVIDE DYNAMIC FORCING FOR
ASCENT IN A MOISTURE RICH ENVIRONMENT. PRECIPITABLE WATER AMOUNTS
WILL RANGE FROM 1.0" TO 1.5" DURING THESE PERIODS WHICH RANKS IN
THE TOP 90TH PERCENTILE. SCATTERED THUNDERSTORMS AND WIDESPREAD
RAIN SHOWERS ARE EXPECTED. GIVEN THE FLASH FLOODING THAT HAS
OCCURRED IN JUNE/EARLIER THIS WEEK ACROSS AREA, THE GROUND IS
CLOSING IN ON SATURATED. THUS, THIS PERIOD WILL NEED TO BE
MONITORED FOR NOT ONLY AN ISOLATED SEVERE RISK, BUT THE POTENTIAL
IMPACTS COMPOUNDING FROM ADDITIONAL HEAVY RAINFALL.
MAIN CONCERNS TO WATCH FOR WILL BE ANY SHARP FRONTAL GRADIENTS
THAT PROVIDE FOCUS TO LIFT AND TRAINING THUNDERSTORMS. CURRENTLY
WITH THE WARM FRONT'S GRADUAL SLOPE THIS DOES NOT LOOK TO BE THE
CASE. BUT, MESOSCALE BOUNDARIES COULD BEGIN TO FORM UP WHERE NOT
PREVIOUSLY ANTICIPATED... IN WHICH CASE A FLASH FLOOD WARNINGS MAY
BE ISSUED DURING ISOLATED BOUTS OF HEAVY RAINFALL.
ENSEMBLES SHOW A CONTINUING PROGRESSIVE WEATHER PATTERN UNFOLDING
WITH A SHORTWAVE WEDNESDAY INTO THURSDAY.
THURSDAY NIGHT INTO THE WEEKEND MAIN RIDGE ACROSS THE
INTERMOUNTAIN WEST BEGINS TO STRENGTHEN AND DRAGS 90S FOR HIGHS
INTO THE REGION AND SOME SUPPRESSION FOR SHOWERS AND
THUNDERSTORMS. HOWEVER NORTHEAST MONTANA REMAINS ON THE PERIPHERY
OF THIS RIDGE WHICH COULD REINTRODUCE A NEW SHORTWAVE RATHER THAN
CLEAR SKIES AT ANY TIME WASHING OUT SOME OF THE DRIER CONDITION
CONFIDENCE IN THE ENSEMBLES.
FORECAST CONFIDENCE & DEVIATIONS:
BLENDED SREF FOR POPS THROUGH DAY 2, AND PUT A GREATER EMPHASIS
ON THE HRRR FOR SHORT TERM HEAVIER RAINFALL TONIGHT. NO CHANGES TO
NBM OTHERWISE.
AVIATION
LAST UPDATED: 2000Z
FLIGHT CATEGORY: MVFR - VFR
DISCUSSION: LATE EVENING SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO ENTER FROM THE SOUTHWEST INTO TAF CITES BEGINNING 6Z. PERIODS
OF MODERATE TO HEAVY RAINFALL WILL BRING INTERMITTENT MVFR
CONDITIONS THROUGH LATE TUESDAY NIGHT.
WIND: E AT 10 TO 15 KTS DECREASING TO AROUND 10 KTS THROUGH
TONIGHT.
GGW WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM 10 PM MDT THIS EVENING THROUGH LATE TUESDAY
NIGHT FOR CENTRAL AND SOUTHERN VALLEY-DAWSON-GARFIELD-MCCONE-
PRAIRIE-RICHLAND-WESTERN ROOSEVELT-WIBAUX.
WEATHER.GOV/GLASGOW
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