093
FXUS65 KGGW 110523
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1123 PM MDT FRI JUL 10 2026
KEY MESSAGES
- DANGEROUS HEAT AND HUMIDITY ARE EXPECTED TO CAUSE IMPACTS TO
NORTHEAST MONTANA THIS WEEKEND. HIGHS WILL BE IN THE 90S AND
100S WITH LOWS IN THE MID 60S TO MID 70S. AN EXTREME HEAT
WARNING HAS BEEN ISSUED FOR SATURDAY THROUGH SUNDAY NIGHT.
- HOT AND DRY WEATHER AND BREEZY CONDITIONS WILL LEAD TO NEAR
CRITICAL FIRE WEATHER CONCERNS FOR SUNDAY AFTERNOON, BUT RECENT
PRECIPITATION AND GREEN FUELS MAY LIMIT THE EXTENT OF THIS
RISK.
- TEMPERATURES WILL MODERATE EARLY NEXT WEEK, BUT ARE EXPECTED TO
REMAIN ABOVE NORMAL. PRECIP CHANCES BEGIN TO RETURN TUESDAY
NIGHT.
DISCUSSION
WEATHER PATTERN OVERVIEW:
A LARGE UPPER RIDGE IS SLOWLY BUILDING OVER THE AREA. SOUTHEAST
WINDS AT LOW LEVELS WILL HELP TRANSPORT WARM AIR NORTHWARD INTO
OUR AREA. THE PEAK IN INTENSITY OF THE RIDGE IS LIKELY TO BE
SUNDAY, WITH ALMOST THE ENTIRE AREA EXPECTED TO BE FROM AROUND 98
TO 110 DEGREES FOR A HIGH TEMPERATURE. THE BASE NBM INDICATES LOWS
STAYING ABOVE 65 DEGREES FOR SATURDAY NIGHT, 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 AND SUNDAY AFTERNOON. ANY FORCING
OVER THE AREA WOULD BE ENOUGH TO GENERATE AN INTENSE STORM SINCE
RECENT RAINFALL HAS HELPED KEEP HIGH DEWPOINT AIR IN PLACE,
ESPECIALLY IN THE EAST. 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 SATURDAY AND SUNDAY.
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. 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
2000J/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. A
PUSH INTO THE NORTHWEST IS LIKELY TO OCCUR BY TUESDAY EVENING, SO
SHOWER AND THUNDERSTORMS WILL NEED TO BE MONITORED FOR SEVERE
WEATHER CHANCES AGAIN FROM THEN ONWARD.
FORECAST CONFIDENCE & DEVIATIONS:
DEVIATIONS TO NBM INCLUDE... USING A CAMS BLEND OF RAP, HRRR,
NAMNEST, FV3, ARW TO PRODUCE AN NPOP BLEND FOR POPS AND THEN
SHRINK_STRETCH ALL HOURLY GRIDS UP FOR THE FINAL POP PRODUCT
THROUGH 18Z. NBM ENSEMBLE WAS NOT ACCOUNTING AT ALL FOR SHOWERS
AND THUNDERSTORMS ON RADAR DEVELOPING OVER SOUTH CENTRAL MONTANA
LAST EVENING AND MAKING IT'S WAY INTO OUR SOUTHWEST CWA DURING THE
EARLY MORNING HOURS. NDFD WIND AND WINDGUST ALSO USED THE SAME
BLEND. INCREASED SKY WITH A 2X POP LAYERED ON TOP OF NBM SKY IN
ATTEMPT TO KEEP THE OLD NBM FIELD IN PLACE UNDER THE HOOD. SKY
NEEDED TO BE IMPROVED BEYOND THIS, BUT BOTH NBM10 AND NBM90 HOURLY
DATA IS NO LONGER PRODUCED TO FIX IT. DID ALL THIS THROUGH
18Z/NOON TODAY.
THERE IS HIGH CONFIDENCE ON TEMPERATURES EXCEEDING 95 DEGREES FOR
HIGH TEMPERATURES AND LOW TEMPERATURES STRUGGLING TO DROP BELOW
65 DEGREES THIS WEEKEND.
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 HIGH CONFIDENCE OF PRECIPITATION CHANCES RETURNING BY
TUESDAY EVENING.
/GAH
AVIATION
UPDATED: 0520Z
FLIGHT CATEGORY: VFR
DISCUSSION: MAINLY DRY WEATHER AND MOSTLY CLEAR SKIES ARE
EXPECTED OVER THE TAF CYCLE AS AN UPPER RIDGE BEGINS TO GAIN AN
INFLUENCE.
DENSITY ALTITUDE: HOT TEMPERATURES NEAR OR 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 18 TO 03Z TODAY AND SUNDAY.
WIND: LIGHT AND VARIABLE OR E AT 10 KTS OR LESS THIS MORNING.
VARYING FROM E TO S AT 5 TO 15 KTS THIS AFTERNOON AND EVENING.
BECOMING LIGHT AND VARIABLE OVERNIGHT.
GAH
GGW WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING FROM 6 AM SATURDAY TO 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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