textproduct: Glasgow

KEY MESSAGES

- Warm weather is expected today and Saturday before the ridge breaks down. There is a slight chance of storms in the east late this afternoon and tomorrow afternoon (5 percent).

- A Red Flag Warning is in effect from now through 9 PM. - Sunday onward expect temperatures to trend lower with accumulating rain through Tuesday. The highest amounts are expected north of the Missouri River.

DISCUSSION

WEATHER PATTERN OVERVIEW: Temperatures are a bit on the toasty side with a ridge in place, but not as high as a few models were suggesting. This has lead to some potential instability at the surface, so any storm that breaks the cap may be strong. The ridge is expected to slowly break down this weekend, so precipitation chances will return as well as an upper trough moves in. The GFS and ECMWF ensembles suggest there is high chance of seeing rainfall amounts over half an inch from Sunday through Tuesday north of the missouri river, and lower amounts south of the river. There is a decent chance of over an inch of accumulation north of Highway 2.

An airmass on the humid side is expected to move in from the east on Sunday. Look for chances for showers and isolated strong thunderstorms in some areas on Sunday. A marginal risk of severe weather was issued for most of the area from SPC.

An upper ridge is expected to begin rebuilding on Tuesday night.

FORECAST CONFIDENCE & DEVIATIONS: Main deviations were a few adjustments to PoPs and winds through 6 AM Sunday.

There is low to moderate confidence of the red flag warning verifying in the southeast today since dewpoints are a bit higher than expected there.

There is moderate confidence in rainfall amounts from Sunday through Tuesday.

AVIATION

LAST UPDATED: 1830Z

FLIGHT CAT RANGE: VFR, slight chance MVFR in thunderstorms.

DISCUSSION: There is mostly VFR conditions expected with a ridge in place. The models are struggling to agree on the dewpoints and instability this afternoon and tomorrow afternoon. There is enough instability and forcing to bring a slight chance of thunderstorms to KOLF, KSDY, and KGDV late this afternoon through sunset, and a similar story tomorrow. There is low confidence on MVFR conditions occurring overall with this activity.

WIND: East southeast at 13 to 20 knots becoming light after 02Z. Winds for KGGW are expected to occur from the north at 6 to 12 knots after 03Z. Then northeast at 6 to 13 knots after 16Z for all sites.

GGW WATCHES/WARNINGS/ADVISORIES

Lake Wind Advisory until 2 PM MDT this afternoon for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum.

Red Flag Warning until 9 PM MDT this evening for Dawson/McCone/Prairie/Richland/Wibaux Counties.