Area Forecast Discussion
Issued by NWS Glasgow, MT
Issued by NWS Glasgow, MT
217 FXUS65 KGGW 200840 AFDGGW Area Forecast Discussion National Weather Service Glasgow MT 240 AM MDT Thu Jun 20 2024 .DISCUSSION... KEY MESSAGES: - Shower and thunderstorm chances increase through Friday, when stronger storms and a more widespread wetting rain is expected. - An isolated severe cell or two Friday late afternoon and early evening may be possible. - A slow warm up is expected through Sunday when some 90s for highs likely appear. WEATHER PATTERN OVERVIEW: A dry morning today will lead into afternoon rain showers and isolated thunderstorms with most coverage looking to be south of the Missouri River. SPC`s HREF is point toward some gusty winds with these cells upward of 50 mph. But severe weather is not really expected. However, a shortwave arriving Friday afternoon does look like it has the chance for a isolated severe cell or two with about 1000 J/kg CAPE, bulk shear around 40-50 kts, and precipitable water over 1 inch. The one problem with this environment appears in the NAM forecast soundings and that is a cooler than average surface layer which will keep most convection elevated rather than surface based, and may prevent strong winds initially. That being said CAMs are point towards strong cells embedded in light shower activity which could form their own environments and CAMs also point towards a couple 50-65 mph gusts that could occur with the strongest cells. Chance of severe weather in the GGW CWA friday late afternoon early evening is about 60%. Chance of a single point getting hit by it is less than 10%. Rain totals with this passage vary from a tenth to a half inch over the CWA. GAH && .AVIATION... LAST UPDATE: 0830Z FLIGHT CAT RANGE: VFR. DISCUSSION: SKC morning will lead to SCT/BKN mid level cumulus clouds in the early afternoon and scattered showers and isolated thunderstorms in the late afternoon and early evening, especially south of the Missouri River. Mainly KSDY and KGDV will be impacted but its not out of the realm of possibility for the other two terminals to get hit. Isolated activity could last through midnight. SFC WIND: Backing E to SE and light through the morning. Then, increasing to 10-15 kts this afternoon. Calming to less than 10 kts this evening through tonight. Expect gusty and erratic winds near any thunderstorm. GAH && .GGW WATCHES/WARNINGS/ADVISORIES... None. && $$ weather.gov/glasgow