textproduct: Glasgow

KEY MESSAGES

- Scattered to occasional showers and a few isolated thunderstorms are expected to occur now through Friday night. Rain accumulations between two tenths of an inch up to about 1.4 inches are expected in that period.

- Winds are expected to be gusting around 30 mph on Fort Peck Lake through noon today.

- Precipitation chances don't completely go away this weekend and into early next week, but overall conditions will trend towards drier and warmer.

DISCUSSION

WEATHER PATTERN OVERVIEW: An upper trough over the Midwest and another one over the Pacific northwest are expected to work in tandem (another word for 'together') by combining into one trough starting tonight. This trough is expected to bring significant rain to a good portion of the area from now through Friday night. The latest ECMWF and GFS ensembles are in fair agreement this trough will break up this weekend. Fairly zonal flow is expected to occur early next week, so there is uncertainty regarding precipitation chances since shortwave troughs are challenging to predict in this flow pattern. It is typical to only accurately predict shortwave troughs a few days in advance.

For precipitation amounts through Friday night, the highest amounts are expected in the eastern half of the area with a few locations exceeding one inch. There is more uncertainty in the western half of the County Warning Area, but there is still a decent shot of reaching a quarter of an inch. A few spots in the southeastern counties accumulated 0.5 inches to 1.34 inches with the storms this evening, so it will be important to watch potential flooding there if rain rapidly accumulates with any future embedded thunderstorms.

A marginal risk of excessive rainfall is expected today and Friday. There is a slight risk for excessive rain today. Will hold off on any Flood Watches for now.

FORECAST CONFIDENCE & DEVIATIONS: Increased the winds through noon today since observations were a bit stronger than the base forecast.

There is high confidence in rainfall amounts in the east, with low to moderate confidence in the west through Friday night.

There is moderate to high confidence in reaching gusts to 30 mph on Fort Peck Lake in correspondence with the Lake Wind Advisory in effect through noon today.

There is moderate confidence that any thunderstorms will remain below severe limits from now through Friday night.

AVIATION

LAST UPDATE: 0630Z.

FLIGHT CAT RANGE: VFR, scattered MVFR and IFR after 12Z this morning.

DISCUSSION: Mid clouds will continue to increase as the upper level low moves closer. There will off and on rain showers through the period. There is high confidence (70 percent) of MVFR to IFR ceilings occurring for KOLF and KGGW through 00Z Friday, and low confidence for KSDY and KGDV. The highest likelihood for thunder is from 22Z to 06Z Friday.

WIND: Mainly east northeast at 8 to 19 kts with gusts ranging from 18 to 28 knots.

GGW WATCHES/WARNINGS/ADVISORIES

Lake Wind Advisory until noon MDT today for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum.