926
FXUS65 KGGW 111825
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1225 PM MDT SAT JUL 11 2026
KEY MESSAGES
- DANGEROUS HEAT AND HUMIDITY ARE EXPECTED TO CAUSE IMPACTS TO
NORTHEAST MONTANA FOR TODAY INTO TOMORROW NIGHT. HIGHS WILL BE
IN THE 90S AND 100S WITH LOWS IN THE MID 60S TO MID 70S. AN
EXTREME HEAT WARNING IS IN PLACE FROM NOW THROUGH SUNDAY
EVENING.
- THERE IS A CHANCE OF DRY THUNDERSTORMS IN THE WEST TOMORROW
AFTERNOON. A SEVERE GUST IS POSSIBLE.
- TEMPERATURES WILL MODERATE EARLY NEXT WEEK, BUT ARE EXPECTED TO
REMAIN ABOVE NORMAL. PRECIPITATION CHANCES BEGIN TO RETURN
TUESDAY NIGHT.
DISCUSSION
WEATHER PATTERN OVERVIEW:
AN UPPER RIDGE IS OVER THE AREA, AND THE PEAK HEAT IS EXPECTED TO
BUILD IN TOMORROW AFTERNOON BEFORE THE RIDGE BREAKS DOWN SLIGHTLY
FOR MONDAY. THE BASE NBM INDICATES LOWS STAYING ABOVE 65 DEGREES
FOR TONIGHT, SUNDAY NIGHT, AND MONDAY NIGHT, SO IT WILL BE
DIFFICULT TO STAY COOL ENOUGH TO SLEEP COMFORTABLY. THERE ARE
SMALL WIGGLES IN THE UPPER LEVEL FLOW FOR VARIOUS CAMS TOMORROW
AFTERNOON, ESPECIALLY IN THE WEST HALF OF THE AREA. ANY FORCING
OVER THE WEST WOULD BE ENOUGH TO GENERATE AN INTENSE DRY THUNDERSTORM
SINCE CLOUD BASES WILL BE VERY HIGH BASED ON HOT SURFACE
TEMPERATURES. WE WILL KEEP AN EYE ON THIS POTENTIAL, BUT STORM
COVERAGE IS EXPECTED TO BE LOW AT THE VERY LEAST. THERE IS AN
EXTREME HEAT WARNING IN PLACE FOR THE HEAT FROM NOW THROUGH SUNDAY
EVENING.
THERE IS A LOW (10 PERCENT) CHANCE OF A SHORTWAVE MOVING THROUGH
AND USING THE SFC BOUNDARIES NEAR OR AFTER PEAK HEATING TO
GENERATE A STRONG THUNDERSTORM OR TWO TODAY IN THE FAR NORTH.
THERE IS A SIMILAR EVENT EXPECTED ON SUNDAY, WITH THIS LOW CHANCE
STARTING MOSTLY IN CENTRAL MONTANA AND MOVING INTO OUR CWA. ONE
CAM SUGGESTS A SEVERE GUST OR TWO WITH THE PASSAGE. WITH NEAR
INVERTED VS ON FCST SOUNDINGS CAN NOT RULE THIS OUT DUE TO HIGH
DCAPE (1500 TO 2600 J/KG).
THE LATEST GFS AND ECMWF ENSEMBLE SUGGESTS A TOPPLING OF THE
RIDGE CREST TO THE EAST BY LATE MONDAY EVENING, SO CENTRAL
MONTANA IS EXPECTED TO START TO SEE PRECIPITATION CHANCES AGAIN BY
THE TIME WE GET TO TUESDAY AFTERNOON. THE BASE NBM SUGGESTS THESE
SHOWER AND STORM CHANCES WILL CONTINUE THROUGH LATE IN THE
UPCOMING WORK WEEK.
FORECAST CONFIDENCE & DEVIATIONS:
THE MAIN DEVIATION WAS TO WINDS FOR TOMORROW BY USING THE HRWFV3.
THERE IS HIGH CONFIDENCE ON TEMPERATURES EXCEEDING 95 DEGREES FOR
HIGH TEMPERATURES AND LOW TEMPERATURES STRUGGLING TO DROP BELOW
65 DEGREES THIS WEEKEND, AND FOR HIGHS EXCEEDING 90 ON MONDAY.
THERE IS MODERATE CONFIDENCE THAT FIRE WEATHER WILL HOLD OFF FOR
AT LEAST THE NEXT WEEK. RECENT RAINS ARE KEEPING THE VEGETATION
PRETTY GREEN, SO FIRE CONCERNS ARE LOW.
THERE IS MODERATE CONFIDENCE OF AN ISOLATED DRY THUNDERSTORM
PRODUCING A 60 MPH WIND GUST ON SUNDAY FROM 2 PM TO 8 PM IN THE
WESTERN PART OF THE AREA.
THERE IS HIGH CONFIDENCE OF PRECIPITATION CHANCES RETURNING BY
TUESDAY EVENING.
AVIATION
UPDATED: 1830Z
FLIGHT CATEGORY: VFR
DISCUSSION: MAINLY DRY WEATHER AND MOSTLY CLEAR SKIES ARE
EXPECTED OVER THE TAF CYCLE. A FEW MODEL RUNS SUGGEST ISOLATED DRY
THUNDERSTORMS MAY IMPACT KGGW TOMORROW AFTERNOON THOUGH. THERE IS
LOW CONFIDENCE IN ISOLATED GUSTY WINDS AS HIGH AS 60 MPH FROM 21Z
SUNDAY TO 02Z MONDAY. THERE ARE ALMOST NO RADAR ECHOES SHOWING UP
IN THE MODELS, SO A GUST OF WIND MAY SIMPLY COME OUT OF AN
INNOCENT LOOKING CLOUD.
DENSITY ALTITUDE: HOT TEMPERATURES NEAR AND ABOVE 100 DEGREES
WILL LEAD TO NEEDS OF INCREASED LENGTH OF RUNWAY AND INCREASED
POWER TO TAKE OFF. WORST TIMES WILL BE IN THE AFTERNOON AND
EVENING FROM 18Z TO 03Z TODAY, AND THE SAME TIME FRAME FOR
SUNDAY.
WIND: SOUTH SOUTHEAST AT 7 TO 15 KNOTS.
GGW WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING UNTIL 6 AM MDT MONDAY FOR CENTRAL AND
SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-DANIELS-DAWSON-
EASTERN ROOSEVELT-GARFIELD-MCCONE-NORTHERN PHILLIPS-NORTHERN
VALLEY-PETROLEUM-PRAIRIE-RICHLAND-SHERIDAN-SOUTHWEST PHILLIPS-
WESTERN ROOSEVELT-WIBAUX.
WEATHER.GOV/GLASGOW
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