989
FXUS65 KGGW 191903
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
103 PM MDT TUE MAY 19 2026
KEY MESSAGES
- ISOLATED THUNDERSTORMS ARE EXPECTED TO TRACK IN FROM THE WEST
THIS AFTERNOON AND EVENING, MAINLY WEST OF A LINE EXTENDING
THROUGH OPHEIM TO GLASGOW TO JORDAN.
- MORE SCATTERED THUNDERSTORMS ARE EXPECTED WEDNESDAY AFTERNOON
AND EVENING, AND AN ISOLATED STORM MAY BE ON THE STRONGER SIDE
WITH WIND GUSTS TO 50 MPH.
- WARMER TEMPERATURES ARE FORECAST FOR THIS WEEKEND WITH HIGHS IN
THE 70S AND 80S.
DISCUSSION
WEATHER PATTERN OVERVIEW:
AN INITIAL SHORTWAVE ON NORTHWEST FLOW ALOFT TRACKING BETWEEN THE
RIDGE TO THE WEST AND TROUGH TO THE EAST LOOKS TO PROVIDE ENOUGH
DYNAMIC SUPPORT FOR ISOLATED SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND EVENING. MUCH OF THIS IS EXPECTED TO QUICKLY
DIMINISH AFTER SUNSET WITH LITTLE IF ANY FANFARE.
ON WEDNESDAY, A LOW PRESSURE TROUGH OVER CENTRAL MONTANA WILL
TRACK EAST WITH A COLD FRONT PUSHING THROUGH EASTERN PARTS OF THE
STATE. THE HREF IS SUPPORTIVE OF A LITTLE MORE WIDESPREAD
CONVECTION BETWEEN ABOUT 21Z AND 03Z. THE MAX ENSEMBLE WIND GUST
GUIDANCE ALSO SUGGESTS THAT A FEW OF THE STORMS MAY BE CAPABLE OF
STRONG WIND GUSTS TO AROUND 50 MPH. THE UPPER TROUGH WILL SLIDE
EAST ON THURSDAY WITH LINGERING SHOWERS AND PERHAPS ISOLATED
THUNDERSTORMS. QPF OVERALL WILL BE LIGHT WEDNESDAY AND THURSDAY,
THOUGH AN ISOLATED WETTING RAIN IS POSSIBLE WITH THE STEADIER MORE
CONCENTRATED CONVECTION.
ENSEMBLES ARE ATTEMPTING TO SHOW A RIDGE PATTERN EMERGING OVER THE
WEEKEND, THOUGH POTENTIALLY STILL WITH EMBEDDED SHORTWAVES. IN
GENERAL THIS WILL MEAN A WARMING TREND THOUGH POTENTIALLY WITH AN
ISOLATED THUNDERSTORM AT TIMES.
FORECAST CONFIDENCE & DEVIATIONS:
HIGH RESOLUTION GUIDANCE WAS USED FOR NEAR TERM POPS WITH
ADDITIONAL REFINEMENTS FOR COLLABORATION PURPOSES. SOME OF THE
HREF MEMBERS INTRODUCE CONVECTION A BIT EARLIER INTO THE AFTERNOON
ON WEDNESDAY, SOMETHING FUTURE SHIFTS MAY NEED TO BETTER ACCOUNT
FOR. OTHERWISE, CONFIDENCE IS MODERATE TO HIGH ON ISOLATED TO
SCATTERED COVERAGE GIVEN MODEL CONSENSUS. ENSEMBLE SPREAD
INCREASES TOWARD THE WEEKEND WITH CONFIDENCE INCREASING FOR THE
WARM UP, BUT LESS CONFIDENCE EXISTS ON EMERGING PRECIPITATION
CHANCES AT LARGER TIME SCALES DUE TO ENSEMBLE SPREAD, AND SHORTWAVE
TIMING.
AVIATION
LAST UPDATED: TUESDAY MAY 19, 2026 AT 1845Z
FLIGHT CAT RANGE: VFR.
DISCUSSION: MOSTLY SUNNY SKIES ARE EXPECTED TO START OUT THOUGH
LOOK FOR INCREASING CUMULUS CLOUD AND HIGH CIRRUS THIS EVENING AS
ISOLATED THUNDERSTORMS REMAIN MAINLY WEST OF AREA TERMINALS.
WIND: WINDS WILL BE SOUTH TO SOUTHEAST THIS AFTERNOON AND EVENING
AT 10 TO 15 KTS, DIMINISHING TO AROUND 10 KTS OR LESS AFTER 03Z.
GGW WATCHES/WARNINGS/ADVISORIES
NONE.
WEATHER.GOV/GLASGOW
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