394
FXUS65 KGGW 160817
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
217 AM MDT SAT MAY 16 2026
KEY MESSAGES
- WIDESPREAD RAIN BEGINNING TONIGHT LASTING THROUGH TUESDAY. LOW
END CHANCES FOR SEEING A WEAK THUNDERSTORM TONIGHT.
- OVERNIGHT TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED TO BE
NEAR FREEZING.
- BREEZY CONDITIONS RETURN TONIGHT. ISOLATED GUSTS UP TO 40 MPH
WILL BE POSSIBLE OVERNIGHT.
DISCUSSION
WEATHER PATTERN OVERVIEW:
UPPER TROUGHING OVER MUCH OF THE WESTERN CONUS WILL BRING WELL
BELOW NORMAL TEMPERATURES AND WIDESPREAD PRECIPITATION THROUGH THE
BEGINNING OF THE WORK WEEK. PRECIPITATION WILL BEGIN TO PUSH EAST
INTO EASTERN MT AROUND 3 PM THIS AFTERNOON AND CONTINUE THROUGH
MONDAY NIGHT. BY THE EARLY EVENING, GUSTY SHIFTING WINDS 15 TO 20
MPH WITH GUSTS TO 40 MPH ARE EXPECTED FOLLOWING A LOW PRESSURE
SYSTEM PASSING THROUGH THE REGION. WINDY CONDITIONS MAY OVERLAP
WITH A DRY SLOT OVER SOUTHEASTERN ZONES TONIGHT INTO TOMORROW
MORNING. THIS IS WHERE THE MOST UNCERTAINTY LIES, AS THE LOCATION
OF THE DRY SLOT AND BY EXTENSION THE TIMING AND LOCATION OF THE
LOW WILL DETERMINE HOW MUCH PRECIPITATION WE'LL GET. HIGHEST
TOTALS LOOK TO BE NORTH OF THE MISSOURI RIVER RANGING FROM
0.01"-0.03" IN SOUTHERN GARFIELD TO ~0.25" ALONG HWY2 AND UPWARDS
OF 0.6"-0.8" IN NORTHWEST PHILLIPS COUNTY.
WHILE THUNDERSTORMS ARE UNLIKELY WITH THIS SYSTEM, THERE IS A
<15% CHANCE FOR THUNDER TONIGHT. AS THE LOW PRESSURE MOVES IN, SOME
CAMS INDICATE WIND GUSTS EXCEEDING 50 MPH IN THE FAR SOUTHEAST TONIGHT.
SNOW STILL REMAINS UNLIKELY, HOWEVER, PERIODS OF MIXED
PRECIPITATION NEAR THE INTERNATIONAL BORDER AND IN THE LITTLE
ROCKERS DURING THE NIGHTTIME HOURS IS POSSIBLE.
THE UPPER TROUGH WILL CONTINUE TO REMAIN OVER THE AREA FOR THE
NEXT SEVERAL BEFORE BREAKING DOWN. A WARM UP LOOKS TO RETURN FOR
THE WEEKEND. WHO'S READY FOR A ROLLERCOASTER??
FORECAST CONFIDENCE & DEVIATIONS:
BLENDED HIRES FV3 AND SREF FOR PRECIP THROUGH MONDAY NIGHT. VERY
GOOD MODEL AGREEMENT IN A DRY SLOT MOVING THROUGH IN THE EARLY
MORNING HOURS ON SUNDAY. THERE IS LESS AGREEMENT ON HOW FAR NORTH
IT EXTENDS.
A LAKE WIND ADVISORY IS LIKELY TO BE NEEDED FOR TONIGHT, AS WINDS
MEETING CRITERIA ARE MARGINAL RIGHT NOW. I OPTED TO NOT BLEND ANY
NBM90 IN WINDS FOLLOWING THE UPDATE TO NBM 5.0 - WILL HAVE TO SEE
HOW THE FORECAST CHANCES FOLLOWING THE NEXT RUN.
AVIATION
LAST UPDATED: 0730Z
FLIGHT CAT RANGE: VFR TODAY, MVFR TONIGHT
DISCUSSION: SCATTERED HIGH CLOUDS WITH INCREASING CLOUD COVER
BEFORE A WIDESPREAD PRECIPITATION BEGINS TO PUSH EAST OVER TAF
SITES AFTER 0Z TONIGHT. THE CHANCE OF SEEING A WEAK THUNDERSTORM
IS 10 TO 15 PERCENT, OPTED TO LEAVE IT OUT OF TAFS AT THIS TIME.
WINDS: LIGHT AND VARIABLE THROUGH 18Z FOLLOWED BY GUSTY, SHIFTING
WINDS 15 TO 20 MPH WITH GUSTS TO 40 MPH FOLLOWING A LOW PRESSURE
SYSTEM PASSING THROUGH THE REGION. WINDS WILL BE PREDOMINANTLY
EAST THROUGH 3Z TOMORROW, VEERING WEST AROUND 16Z.
FIRE WEATHER
ENHANCED FIRE WEATHER CONCERNS WILL OCCUR THIS AFTERNOON WITH MIN
RH IN THE 20S IN MOST AREAS WITH EAST TO SOUTHEAST WINDS. A
WIDESPREAD PRECIPITATION EVENT WILL MOVE IN FROM THE WEST AFTER 3
PM THIS AFTERNOON AND CONTINUE THROUGH MONDAY NIGHT. GUSTY
SHIFTING WINDS 15 TO 20 MPH WITH GUSTS TO 40 MPH ARE EXPECTED
TONIGHT AND SUNDAY AS A LOW PRESSURE SYSTEM PASSES THROUGH THE
REGION. WHILE MOST AREAS NORTH OF THE MISSOURI RIVER WILL HAVE
WETTING RAINS FROM THIS SYSTEM, A DRY SLOT TONIGHT AND SUNDAY
SOUTH OF THE MISSOURI RIVER WILL LIMIT RAINFALL AMOUNTS FROM THIS
SYSTEM.
GGW WATCHES/WARNINGS/ADVISORIES
NONE.
WEATHER.GOV/GLASGOW
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