Area Forecast Discussion
Issued by NWS Glasgow, MT
Issued by NWS Glasgow, MT
423 FXUS65 KGGW 150824 AFDGGW Area Forecast Discussion National Weather Service Glasgow MT 224 AM MDT Sat Jun 15 2024 .DISCUSSION... KEY MESSAGES: - Pattern change starts today as a cold front brings showers and thunderstorms with eastern zones seeing the greatest risk of a mixed severe hail/wind threat. - Cooler temperatures begin Sunday, with the coldest readings occurring on Monday and Tuesday. - More widespread rain moves in during Monday and Tuesday. - Warming trend later this week, but things remain unsettled with daily shower and thunderstorm chances. WEATHER PATTERN OVERVIEW: Today the first Pacific Northwest Trough will begin to settle into the area driving a cold front ahead of it. This will not only be the beginning of a pattern change to below average and wetter conditions, but this front will be the focusing mechanism for another round of afternoon and evening thunderstorms. SPC has the eastern half of our CWA, roughly east of a line from Opheim to Glasgow to Jordan in a slight risk for severe weather with large hail and damaging winds the main threat. Sunday will be cooler behind the front with a little break in the action overall before a stronger Pacific trough moves in Monday bringing widespread rain and even cooler temperatures at 10-20 degrees below mid June averages for both Monday and Tuesday. A warming trend begins Wednesday with temperatures warming close to late June averages by the end of the week. Still unsettled with afternoon showers and thunderstorms continuing to be a possibility. FORECAST CONFIDENCE and DEVIATIONS: There is a moderate to high (50-90%) probability for a wetting rain (0.10") across much of the region with today`s system with the highest chances in the northeast corner of the state. Low to moderate probability (25-60%) of 0.25". QPF`s have trended downward some, especially in the southeastern zones. For the Monday/Wednesday AM system, QPF amounts have trended downward but are higher than today`s system, with a probability around 70-80% for at least 0.25", 40-60% for 0.50", and 10-35% for 1". Confidence is lower Wednesday onward on shower and thunderstorm chances and timing as models start diverging in that time period. -Bernhart && .AVIATION... LAST UPDATE: 0830Z FLIGHT CAT RANGE: VFR, Brief MVFR possible near storms. DISCUSSION: Cold front pushing east will trigger numerous showers and thunderstorms today with the best chances occurring during the afternoon and evening. A risk of severe storms is possible especially east of a line from Opheim to Glasgow to Jordan with strong gusty winds and large hail being the main threat. WIND: KGGW: N-NW 10-15kts, increasing to NW 15-20kts, gusts 30-35kts after 00Z. KOLF: NE-N 10-15kts, increasing to NW 15-20kts, gusts 30-35kts after 02Z. KSDY: E-NE 10-15kts, increasing to NW 15-20kts, gusts 30-35kts after 03-04Z. KGDV: E-SE 10-15kts, increasing to NW 15-20kts, gusts 30-35kts after 01-03Z. -Bernhart && .GGW WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory from 6 PM this evening to 9 PM MDT Sunday for Central and Southeast Phillips-Central and Southern Valley- Garfield-McCone-Petroleum. && $$ weather.gov/glasgow