Area Forecast Discussion
Issued by NWS Glasgow, MT
Issued by NWS Glasgow, MT
042 FXUS65 KGGW 291113 AFDGGW Area Forecast Discussion National Weather Service Glasgow MT 513 AM MDT Wed May 29 2024 .DISCUSSION... KEY MESSAGES: - Strong and severe thunderstorms are expected Wednesday afternoon and evening, especially along the SPC slight risk area straddling the Montana/North Dakota border. - Warm but moderately unsettled pattern expected through the weekend and into next week. WEATHER PATTERN OVERVIEW: An upper trough moving toward the northern/Canadian Rockies this morning is continuing to develop an Alberta surface low with an associated cold front. As the front moves east today, the low level jet strengthens, pulling moisture northward along the Montana/North Dakota border. This will set up a favorable scenario for severe thunderstorms, initially across the far eastern zones of eastern Montana for the late afternoon and evening, as noted by SPC with a slight risk area. As the upper trough sweeps across the Canadian prairies, cooler temperatures along with some unstable air lingers over the region for Thursday. Behind the trough, the flow aloft becomes generally zonal, with occasional shortwave disturbances, for warmer and somewhat unsettled conditions through the weekend and into next week. CONFIDENCE & DEVIATIONS: Confidence for severe weather on this afternoon remains high, with CAPE in excess of 1000-2000 J/kg, and moisture advection on the strong low level southeast jet with winds in excess of 30kt. Damaging winds and large hail will be the main threats. HREF ensemble only giving a 10% probability for updraft helicity in excess of 75 m2/s2 through 00z Thursday, but it does increase to 30% probability in the early evening. With PW over 1" indicated, heavy rain is also a possibility near the North Dakota border. && .AVIATION... VFR through late afternoon when a cold front will cross the region with scattered showers and thunderstorms. Some of the stronger storms could result in brief periods of IFR or worse for KSDY and KGDV if a storm happens to pass directly overhead. Winds will increase from the northwest behind the cold front, Gusty, erratic, severe wind gusts are expected near the stronger storms this evening. && .GGW WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory from 11 AM this morning to 9 PM MDT Thursday for Central and Southeast Phillips-Central and Southern Valley- Garfield-McCone-Petroleum. && $$ weather.gov/glasgow