772
FXUS65 KGGW 120937
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
337 AM MDT FRI SEP 12 2025
DISCUSSION
KEY MESSAGES:
1) A MARGINAL RISK FOR SEVERE THUNDERSTORMS EXISTS TODAY ACROSS NE
MONTANA WITH THE GREATEST RISK DURING AFTERNOON AND EVENING HOURS.
2) SHOWERS AND GENERAL THUNDER WILL LIKELY CONTINUE AT TIMES
TONIGHT THROUGH THE WEEKEND, THOUGH DECREASING COVERAGE IS
EXPECTED SUNDAY AND MONDAY.
3) THE NEXT SYSTEM HAS SHIFTED SOUTH MONDAY NIGHT INTO TUESDAY BUT
THAT REMAINS THE NEXT CHANCE FOR SCATTERED SHOWERS AND
THUNDERSTORMS.
WEATHER PATTERN OVERVIEW:
UPPER TROUGH OVER THE WESTERN U.S. WITH IDAHO LOW PRESSURE SYSTEM
WILL CONTINUE SOUTHWEST UPPER FLOW OVER EASTERN MONTANA. THIS WILL
HELP SET OFF ANOTHER ROUND OF SCATTERED THUNDERSTORMS THIS
AFTERNOON INTO TONIGHT. COOLER AND WET WEATHER WILL LIKELY
CONTINUE OVER THE WEEKEND AS THE SYSTEM TRANSLATES EAST. EXPECT
DECREASING COVERAGE HOWEVER AS THE MAIN LOW LIFTS INTO CANADA
MONDAY MORNING.
THE NEXT LOW EMBEDDED IN THE TROUGH WILL FOLLOW BEHIND IT WITH
ADDITIONAL SHOWER AND THUNDERSTORM CHANCES MONDAY NIGHT INTO
TUESDAY FOR CONTINUING UNSETTLED CONDITIONS. THESE UNSETTLED
CONDITIONS ARE LIKELY TO PERSIST INTO THE MIDLE OF THE WEEK UNTIL
THE TROUGH PATTERN BREAKS DOWN. ENSEMBLES SHOW A RIDGE DEVELOPING
OVER THE SOUTHWESTERN U.S. LATEWEEK WHICH MAY LEAVE MONTANA ON THE
NORTHERN INFLUENCE OR IN SPLIT FLOW DEPENDING ON HOW THAT SHAPES
UP.
FORECAST CONFIDENCE & DEVIATIONS:
NBM MOSTLY LEFT IN PLACE THIS FORECAST CYCLE AS IT CAPTURED
OVERALL EXPECTED TRENDS WELL AND MATCHED FOR COLLABORATION. WILL
NEED TO ASSESS EDITS IN THE NEAR TERM POPS TO REFLECT NEW
MESOSCALE GUIDANCE AS CONVECTIVE TRENDS COME INTO FOCUS.
CONFIDENCE THUS REMAINS MODERATE TO HIGH ON AN ACTIVE PATTERN
THROUGH THE WEEKEND, BUT BELOW AVERAGE ON THE TIMING, PLACEMENT,
AND EXACT PRECIPITATION AMOUNTS GIVEN ENSEMBLE SHIFTS RUN TO RUN.
AVIATION
UPDATE: 0930Z ON 9/12/2025
FLIGHT CAT RANGE: VFR, MVFR IN THUNDERSTORMS.
DISCUSSION: LOW PRESSURE WILL CONTINUE TO INFLUENCE THUNDERSTORM
CHANCES THIS AFTERNOON INTO TONIGHT. WHILE VFR WILL PREVAIL, MVFR
CEILINGS AND VISIBILITIES ARE CERTAINLY POSSIBLE NEAR ANY STORMS
SHOULD THEY PASS DIRECTLY OVER A TAF SITE.
WIND: GENERALLY LIGHT AND VARIABLE, BECOMING ERRATIC AND GUSTY
NEAR THE STRONGER STORMS.
EQUIPMENT: COMMS ISSUES WITH THE KSDY OBSERVATION REMAIN. AMD NOT
SKED WILL REMAIN WITH THE TAF THERE UNTIL TRANSMISSION OF OBS
BECOMES MORE STABLE.
GGW WATCHES/WARNINGS/ADVISORIES
NONE.
WEATHER.GOV/GLASGOW
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