Area Forecast Discussion
Issued by NWS Glasgow, MT
Issued by NWS Glasgow, MT
783 FXUS65 KGGW 262020 AFDGGW Area Forecast Discussion National Weather Service Glasgow MT 220 PM MDT Sun May 26 2024 .DISCUSSION... KEY MESSAGES: 1) Gusty west winds today keep a Lake Wind Advisory in effect from 9 AM to 9 PM. Scattered afternoon and evening thunderstorms could enhance wind gusts and carry small hail. 2) Expect a slow warming trend into Wednesday, when a cold front brings increased chances for strong thunderstorms. WEATHER PATTERN OVERVIEW: Daytime instability thunderstorms are expected to regenerate mainly near the Canadian border this afternoon. West winds at the surface and aloft will combine to bring strong wind gusts to most areas of up to 40 mph and higher with some storms. Limited updraft potential and fast storm motion will limit hail and heavy downpour concerns. On Memorial Day, most of the area will experience the beginning of a warming/drying trend, but the northeast zones could experience a shower or thunderstorm before an upper ridge from the Pacific Northwest moves in. The upper ridge will bring warm sunshine to the area for Tuesday before SW flow and an upper trough approaches Wednesday. This will increase the chances for thunderstorms, some of which could be severe as models are indicating CAPEs over 1000 J/kg in parts of the area! In the wake of a cold frontal passage late Wednesday, conditions will be breezy and not as warm on Thursday. Unsettled conditions are expected to last into Saturday with the passage of the upper trough overhead. CONFIDENCE & DEVIATIONS: +++ AFTERNOON DISCUSSION: The 12Z initialization of the NSSL (an HREF member) was best at capturing the late morning`s convection that popped up on the east side of the Yellowstone River valley. That line has since moved into North Dakota. With synoptic winds already picking up south and west of the Milk River (approaching 30 mph), the general feeling is that winds won`t gust to much from the background wind. An SPS or two may be needed tonight. +++ No deviations were made to the base forecast besides slightly refining the timing of thunderstorm chances and strength of winds today. Confidence is high for temperatures remaining close to normal overall for the next week, while currently medium for receiving strong thunderstorms and widespread rainfall of a quarter inch or more midweek. -Zanker/Enriquez && .AVIATION... LAST UPDATED: 2015Z FLIGHT CAT: VFR (MVFR in isolated shower/thunderstorm) DISCUSSION: Most convective showers has moved into North Dakota. Wrap around showers on the back side of this surface low pressure will bring, at times, brief MVFR conditions. SFC WIND: West of KGGW, expect WNW winds at 10-20 kts gusting 30 kts through 10 PM. Elsewhere, expect similar WNW winds at 10-15kts. Between midnight at 6 AM Monday, winds remain from the WNW at 5-10 kts. The remainder of Monday sees WNW winds pick up to 10-15 kts. -Enriquez && .GGW WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory until 9 PM MDT this evening for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum. && $$ weather.gov/glasgow