789
FXUS65 KGGW 210602
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1202 AM MDT SUN JUN 21 2026
KEY MESSAGES
- AN UPPER LOW WILL HELP BRING SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS ACROSS THE AREA FOR SUNDAY. AN ISOLATED STRONGER
STORM NEAR THE MT/ND BORDER REMAINS POSSIBLE.
- EXPECT LINGERING SHOWERS EARLY NEXT WEEK WITH COOLER
TEMPERATURES, BUT A WARM UP BEGINS BY THE MIDDLE OF THE WEEK.
- ANOTHER SYSTEM IS EXPECTED AT THE END OF THE WEEK TO BRING
ADDITIONAL THUNDERSTORMS TO THE REGION.
DISCUSSION
WEATHER PATTERN OVERVIEW:
AN UPPER TROUGH TRACKING OVER THE REGION WILL LEND SUPPORT TO A
COUPLE OF DIFFERENT ROUNDS OF SHOWERS AND THUNDERSTORMS FOR
SUNDAY. THE TROUGH MAY PRODUCE ENOUGH OF AN UNSTABLE ENVIRONMENT
FOR AN ISOLATED HAIL THREAD, WITH HREF MAX UPDRAFT HELICITY
SHOWING SUPPORT IN THE AFTERNOON HOURS NEAR THE MT/ND BORDER.
GIVEN PRECIPITABLE WATER IN THE FORECAST SOUNDINGS, HEAVY RAINFALL
MAY ALSO RESULT WITH THE STEADIER STORMS.
LOOK FOR LINGERING SHOWERS AND ISOLATED THUNDER EARLY IN THE WEEK
ALONG WITH COOLER TEMPERATURES AS THE UPPER TROUGH SWINGS
THROUGH, WITH A RIDGE HELPING TO BRING ABOUT WARMER TEMPERATURES
AND DRIER WEATHER LATER IN THE WEEK.
ENSEMBLES ARE STARTING TO SHOW THE NEXT SYSTEM APPROACHING BY THE
WEEKEND WITH ADDITIONAL THUNDERSTORM CHANCES EXPECTED AT THAT
TIME.
FORECAST CONFIDENCE & DEVIATIONS:
NBM WAS USED FOR THE FORECAST CYCLE, WHICH CAPTURED THE TRENDS
WELL FOR THE EXPECTED THUNDERSTORM CHANCES ON SUNDAY, FOLLOWED BY
LATER IN THE WEEK. CONFIDENCE REMAINS ABOVE AVERAGE ON
THUNDERSTORM CHANCES FOR TODAY, THOUGH MORE MODERATE CONFIDENCE ON
EXACT PRECIPITATION AMOUNTS AND PLACEMENT OF THE HEAVIER RAINFALL.
AVIATION
LAST UPDATE: SUNDAY JUNE 21, 2026 AT 0600Z
FLIGHT CAT RANGE: VFR TO MVFR.
DISCUSSION: AN UPPER TROUGH PATTERN WILL BRING SEVERAL ROUNDS OF
SHOWERS AND THUNDERSTORMS ON SUNDAY. THE STORMS WILL TEND TO PUSH
EAST INTO ND AFTER 03Z. SOME OF THE STORMS MAY BE ASSOCIATED WITH
BRIEF REDUCTIONS IN VISIBILITY AS WELL AS LOWER CEILINGS.
WINDS: EAST WINDS EARLY WILL SWITCH TO THE WEST AND NORTHWEST AT
5 TO 15 KTS AT KGGW IN THE AFTERNOON. LOOK FOR WINDS BECOMING
SOUTH AT 5 TO 10 KTS AT KOLF, KSDY, KGDV IN THE AFTERNOON. WINDS
MAY BE GUSTY AND ERRATIC WITH THUNDERSTORMS.
GGW WATCHES/WARNINGS/ADVISORIES
NONE.
WEATHER.GOV/GLASGOW
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