965
FXUS65 KGGW 161857
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1257 PM MDT SAT MAY 16 2026
KEY MESSAGES
- AREAS OF RAIN BEGINNING TONIGHT LASTING THROUGH TUESDAY. LOW END
CHANCES FOR SEEING A WEAK THUNDERSTORM TONIGHT. A LAKE WIND
ADVISORY IS IN EFFECT FROM 9 PM TONIGHT THROUGH 9 AM SUNDAY.
- OVERNIGHT TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED TO BE
NEAR FREEZING.
- ISOLATED TO SCATTERED THUNDERSTORMS ON WEDNESDAY AFTERNOON.
DISCUSSION
WEATHER PATTERN OVERVIEW:
UPPER TROUGHING OVER MUCH OF THE WESTERN CONUS WILL BRING WELL
BELOW NORMAL TEMPERATURES AND AREAS OF PRECIPITATION THROUGH THE
BEGINNING OF THE WORK WEEK. PRECIPITATION WILL BEGIN TO PUSH EAST
INTO EASTERN MT AROUND 6 PM THIS AFTERNOON AND CONTINUE THROUGH
MONDAY NIGHT. THERE IS DECENT CHANCE WINDY CONDITIONS MAY OVERLAP
WITH A DRY SLOT OVER SOUTHEASTERN ZONES TONIGHT INTO TOMORROW
MORNING. THE 12Z GFS FROM YESTERDAY AND 12Z GFS ENSEMBLE FROM
TODAY CONTINUE TO SHOW A DRY SLOT SETTING UP OVER THE CENTRAL PART
OF THE AREA TONIGHT, SORT IN THE SHAPE OF AN UPSIDE DOWN U.
PRAIRIE, GARFIELD, WESTERN ROOSEVELT, AND MCCONE COUNTIES ARE THE
MOST LIKELY PLACES TO SEE THE DRY SLOT, SO PRECIPITATION AMOUNTS
ARE BELOW ONE TENTH IN THAT AREA THROUGH TUESDAY. FOR ALL OTHER
COUNTIES, THE MOST LIKELY RANGE OF TOTAL RAINFALL IS ONE TENTH TO
AROUND A HALF AN INCH. THERE IS LESS THAN ONE INCH OF SNOW
FORECAST TO ACCUMULATE IN SOUTHWEST PHILLIPS COUNTY THROUGH
TUESDAY, AND IN THE FAR NORTHERN PARTS OF THE AREA.
WHILE THUNDERSTORMS ARE UNLIKELY WITH THIS SYSTEM, THERE IS A 10
TO 15 PERCENT CHANCE FOR THUNDER TONIGHT. AS THE LOW PRESSURE
MOVES IN, SOME CAMS INDICATE WIND GUSTS EXCEEDING 50 MPH IN THE
FAR SOUTHEAST TONIGHT.
THE UPPER TROUGH WILL CONTINUE TO REMAIN OVER THE AREA AFTER
TUESDAY, ALTHOUGH A BIT WEAKER THAN THIS WEEKEND. THIS WILL LIKELY
ALLOW SHORTWAVE TROUGHS TO SNEAK THROUGH THE OVERALL FLOW,
BRINGING SOME ISOLATED THUNDERSTORM ACTION TO THE AREA. THE NEXT
CHANCE FOR THUNDERSTORMS APPEARS TO BE WEDNESDAY. WHO'S READY FOR
A ROLLERCOASTER??
FORECAST CONFIDENCE & DEVIATIONS:
MADE A DEVIATION TO THE BASE FORECAST IN THE FAR SOUTHEAST PART OF
THE AREA TONIGHT BY INCREASING WINDS MANUALLY BASED ON CAM MODELS.
THERE IS HIGH (80 PERCENT) CONFIDENCE IN THE LAKE WIND ADVISORY
FOR FORT PECK LAKE FOR TONIGHT.
THERE IS MODERATE TO HIGH (50 TO 70 PERCENT) CONFIDENCE IN TOTAL
RAINFALL AMOUNTS THROUGH TUESDAY.
THERE IS MODERATE CONFIDENCE THAT ANY SNOW THAT FALLS IN THE NORTH
AND FAR WEST WILL REMAIN BELOW ONE INCH OF ACCUMULATION.
THERE IS LOW TO MODERATE CONFIDENCE IN SCATTERED THUNDERSTORMS
OCCURRING ON WEDNESDAY AFTERNOON.
AVIATION
LAST UPDATED: 1830Z
FLIGHT CAT RANGE: VFR TODAY, MVFR TONIGHT
DISCUSSION: SCATTERED HIGH CLOUDS WITH A FEW ISOLATED SHOWERS.
CLOUDS WILL CONTINUE TO INCREASE TOWARD OVERCAST AS A MAJORITY OF
THE PRECIPITATION BEGINS TO PUSH EAST OVER TAF SITES AFTER 0Z
SUNDAY. THE CHANCE OF SEEING A WEAK THUNDERSTORM IS 10 TO 15
PERCENT, OPTED TO LEAVE IT OUT OF TAFS AT THIS TIME.
WINDS: FOR KSDY, KGDV, AND KOLF, EAST WINDS 10 TO 20 MPH WITH
GUSTS TO 30 MPH, BECOMING NORTH NORTHEAST AFTER 12Z. FOR KGGW,
SOUTHEAST AT 10 TO 20 WITH GUSTS TO 30 MPH, BECOMING NORTH AFTER
4Z.
GGW WATCHES/WARNINGS/ADVISORIES
LAKE WIND ADVISORY FROM 9 PM THIS EVENING TO 9 AM MDT SUNDAY FOR
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
GARFIELD-MCCONE-PETROLEUM.
WEATHER.GOV/GLASGOW
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