textproduct: Glasgow

KEY MESSAGES

- A frontal passage brings scattered showers and thunderstorms this afternoon and evening. An isolated storm or two may be on the stronger side with wind gusts over 50 mph. - A second round of showers and isolated thunderstorms will be possible near the ND border Thursday afternoon.

- Warmer temperatures are expected beginning Friday with 80s for highs beginning Sunday onward.

DISCUSSION

WEATHER PATTERN OVERVIEW: An upper trough in NW flow has moved into the area. This system will bring a cold front across eastern Montana later this afternoon and evening with rain showers and isolated to scattered thunderstorms currently developing. The HREF shows some isolated cells within this frontal passage producing wind gusts up to about 50 mph which will need to be monitored. Wetting rains will be isolated to the steadier thundershowers. On Thursday, the surface trough that moves into the region starts to stall out at the ND border and will become a focal point from the morning to afternoon hours for additional showers and isolated general thunderstorms.

From Friday into the holiday weekend, an upper level ridge will build in to bring mostly clear and warm to hot conditions as high as the 90s on Memorial Day. Ensemble cluster analyses differ on thunderstorm chances associated with some breakdown of the ridge by the middle of next week.

FORECAST CONFIDENCE & DEVIATIONS: Minimal changes were made to the base forecast to add detail for winds and precipitation associated with today's frontal passage.

Confidence is high for thunderstorms today staying below severe wind limits, as well as the warm up over the weekend. Confidence is then average at best for thunderstorm risk and cooling trend following Memorial Day.

AVIATION

LAST UPDATED: 1900Z

FLIGHT CAT RANGE: VFR to MVFR.

DISCUSSION: A deck of mid-level clouds is moving in with scattered showers and thunderstorms passing through the area this afternoon, starting around 20Z around KGGW/KOLF. There is a outside chance (5%) for one or two cells to become severe with wind gusts up to 50kts, so the TAFS reflect some brief gusts to 30-40 kts. Storms should exit all terminals by about 02Z before clearing out for most of the night with only and isolated showers from then on. There is moderate confidence for a lowering to MVFR ceiling for KSDY and KGDV Thursday afternoon.

WIND: West, briefly increasing to 15-25 kts with the frontal passage this afternoon. Becoming light and variable this evening.

EQUIPMENT: KSDY and KGDV obs are unavailable and will be AMD NOT SKED UFN.

GGW WATCHES/WARNINGS/ADVISORIES

None.