textproduct: Glasgow

KEY MESSAGES

- Thunderstorm chances look to continue through the 4th of July holiday weekend. A few storms could be strong to severe especially today. - Near normal temps will gradually warm to above normal by the end of the weekend.

DISCUSSION

WEATHER PATTERN OVERVIEW: A small upper level trough is expected to remain over the area through Friday. This will generate isolated to scattered severe thunderstorms periodically. Shortwave troughs that move through this flow will aid in initiating the stronger storms. The main severe threats are for the eastern two-third of the area today, and the eastern half of the area on Friday. Early morning storms are expected to exit the area around 4AM this morning.

Based on 0-6km bulk shear and a small amount of surface CAPE over central Montana on July Fourth, there is enough evidence to suggest an isolated strong storms moving across the eastern counties in the afternoon. This is according to a few deterministic NAM model soundings.

The NBM ensembles are suggesting a partial upper ridge mid next week.

FORECAST CONFIDENCE & DEVIATIONS: Deviations were made to account for hourly PoPs and wind gusts from the RAP, HRRR and ARW for a line of storms rolling through early this morning. This allowed us to get a vastly better timing for TAFs.

There is moderate confidence in showers and storms occurring now through Friday, with 12 to 18 hour breaks in between each wave.

There is low to to moderate confidence on thunderstorm activity in the afternoon of the Fourth of July.

There is moderate confidence in a ridge moving in next week, but low confidence on this ridge suppressing all thunderstorm activity.

GAH

AVIATION

LAST UPDATED: 0615Z

FLIGHT CATEGORY: VFR. MVFR in thunderstorms.

DISCUSSION: Shower and thunderstorm activity will move across the area early this morning. First round of storms are expected to exit the area around 9 to 10Z. The second round is expected to form around 21Z this afternoon and last through about 04Z in the evening. Some of these afternoon and evening cells could become severe with large hail and damaging wind.

WIND: Light and variable through the morning. Becoming E at 5 to 15 kts in the early afternoon. Then switching W in the late afternoon/early evening post-front. Decreasing to light and variable overnight. Gusty erratic winds are possible near any thunderstorm.

GAH

GGW WATCHES/WARNINGS/ADVISORIES

None.