777
FXUS65 KGGW 120646
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1246 AM MDT SUN JUL 12 2026
KEY MESSAGES
- DANGEROUS HEAT AND HUMIDITY ARE EXPECTED ACROSS NORTHEAST
MONTANA TODAY. HIGHS WILL BE IN THE 100S. AN EXTREME HEAT
WARNING HAS BEEN ISSUED THROUGH EARLY MONDAY MORNING.
- HOT AND DRY WEATHER AND BREEZY CONDITIONS WILL LEAD TO NEAR
CRITICAL FIRE WEATHER CONCERNS FOR THIS AFTERNOON. WHILE RECENT
PRECIPITATION AND GREEN FUELS MAY LIMIT SOME RISK, INCREASED
DRY THUNDERSTORM DOWNDRAFT GUST CHANCES THIS AFTERNOON WILL PUT
IT OVER THE TOP FOR RED FLAG IN THE SW.
- TEMPERATURES WILL MODERATE EARLY THIS WORK WEEK, BUT ARE
EXPECTED TO REMAIN ABOVE NORMAL. PRECIP CHANCES RETURN TUESDAY
NIGHT INTO WEDNESDAY MORNING.
DISCUSSION
WEATHER PATTERN OVERVIEW:
AN UPPER RIDGE IS OVER THE AREA, AND THE PEAK HEAT IS EXPECTED TO
BUILD IN TODAY BEFORE THE RIDGE BREAKS DOWN SLIGHTLY MONDAY. THE
BASE NBM INDICATES LOWS STAYING ABOVE 65 DEGREES FOR THIS MORNING,
AND MONDAY MORNING. SO, IT WILL BE DIFFICULT TO STAY COOL ENOUGH
TO SLEEP COMFORTABLY. THERE IS AN EXTREME HEAT WARNING IN PLACE
FOR THE HEAT FROM NOW THROUGH SUNDAY EVENING.
THERE ARE SMALL SHORTWAVE WIGGLES IN THE UPPER LEVEL FLOW FOR
VARIOUS CAMS THIS AFTERNOON, ESPECIALLY IN THE WESTERN HALF OF THE
CWA. ANY FORCING OVER THE SOUTH CENTRAL MONTANA WOULD BE ENOUGH
TO GENERATE A DRY THUNDERSTORM OR SHOWERS AND MOVE IT NORTH INTO
OUR WEST BY THE AFTERNOON HOURS. CLOUD BASES WILL BE VERY HIGH
BASED ON HOT SURFACE TEMPERATURES WITH EVAPORATION LEADING TO DRY
THUNDER POTENTIAL. A COUPLE CAMS SUGGEST A SEVERE GUST OR TWO
WITH THE PASSAGE OF THESE CELLS. WITH NEAR INVERTED VS ON FCST
SOUNDINGS CAN NOT RULE THIS OUT DUE TO HIGH DCAPE (1500 TO 2500
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 RISE
AGAIN INTO A WEAK TUESDAY NIGHT/WEDNESDAY MORNING EVENT. THE BASE
NBM SUGGESTS THESE SHOWER AND STORM CHANCES WILL THEN CONTINUE ON
THOUGH SLIGHTLY DIMINISHED THROUGH THE EARLY WEEKEND.
FORECAST CONFIDENCE & DEVIATIONS:
NO DEVIATIONS TO NBM.
THERE IS HIGH CONFIDENCE ON TEMPERATURES EXCEEDING 100 DEGREES
FOR HIGH TEMPERATURES AND LOW TEMPERATURES STRUGGLING TO DROP
BELOW 65 DEGREES FOR SUNDAY, 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 LOW TO MODERATE CONFIDENCE OF AN ISOLATED DRY
THUNDERSTORM PRODUCING A 60 TO 65 MPH WIND GUST FROM 2 PM TO 8 PM
SUNDAY IN THE WESTERN HALF OF THE CWA.
THERE IS HIGH CONFIDENCE OF PRECIPITATION CHANCES RETURNING BY
TUESDAY EVENING.
/GAH
AVIATION
UPDATED: 0430Z
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 THIS AFTERNOON.
THERE IS LOW CONFIDENCE(5-10%) IN ISOLATED GUSTS AS HIGH AS 65
MPH FROM 21-02Z. GUST SIGNATURES ARE SHOWING UP IN HREF CAMS
WHICH LOOK TO LACK THUNDER. SO, A GUST OF WIND MAY SIMPLY COME OUT
OF AN OTHERWISE INNOCUOUS LOOKING DYING RAIN SHOWER AS THEY MOVE
FROM SSW TO NNE IN THE LATE AFTERNOON AND EARLY EVENING.
DENSITY ALTITUDE: HOT TEMPERATURES NEAR AND ABOVE 100 DEGREES
WILL LEAD TO NEEDS FOR INCREASED LENGTH OF RUNWAY AND INCREASED
POWER FOR TAKE OFF. WORST TIMES WILL BE IN THE AFTERNOON AND
EVENING FROM 18Z TO 03Z.
WIND: LIGHT AND VARIABLE THROUGH THE MORNING. VEERING FROM E TO S
AND INCREASING TO 10 TO 20 KTS THIS AFTERNOON. FURTHER VEERING NW
TO N IN THE EVENING BEHIND A FRONT AND REDUCING TO 15 KTS OR LESS
AFTER MIDNIGHT/06Z. GUSTY ERRATIC WIND IS POSSIBLE NEAR ANY STORM
OR SHOWER.
GAH
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.
RED FLAG WARNING FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
SOUTHERN PETROLEUM AND SOUTHERN GARFIELD COUNTIES-THE LOWER
MISSOURI RIVER BREAKS INCLUDING THE CHARLES M RUSSELL NATIONAL
WILDLIFE REFUGE.
WEATHER.GOV/GLASGOW
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