textproduct: Glasgow

KEY MESSAGES

- Showers and isolated thunderstorms taper off through the late afternoon into the evening.

- High pressure brings warm and dry conditions on Thursday.

- Gusty southerly winds Friday turn strong westerly on Saturday following a dry cold front passage.

DISCUSSION

The mid-level shortwave trough continues to push northeast out of eastern Montana towards southern Saskatchewan and northwestern North Dakota. As dynamic lift leaves the region, shower and embedded thunderstorm activity will diminish from southwest to northeast through the remainder of the afternoon into the evening.

Behind the departing wave an upper level ridge of high pressure builds over the Northern Plains through Thursday. This will establish a warming and drying trend across eastern Montana. Thursday will be the warmest day of the with with high temperatures climbing into the upper 70s and 80s which is roughly 15 degrees above normal for late September.

The ridge shifts eastward into the Dakotas on Friday as a trough moves into the Pacific Northwest. A deepening surface low over central Montana will cause a tight pressure gradient producing strong southerly winds across eastern Montana. These winds may approach Lake Wind Advisory criteria for Fort Peck Lake.

A cold front is expected to sweep across the forecast area late Friday night into early Saturday morning. Wind directions will shift sharply to the west-northwest behind the front. The winds will remain elevated throughout Saturday, likely prolonging the potential for hazardous conditions on area lakes. Moisture associated with front will be fairly limited, so no precipitation is expected with this frontal passage.

Westerly upper level flow persist across the region through much of next week. Guidance has begun to show a disturbance moving across the region on Monday. This feature represents the next potential for widespread rain across the area.

AVIATION

LAST UPDATED: 0530Z

FLIGHT CAT RANGE: MVFR improving to VFR for KSDY/KGDV; VFR: KGGW & KOLF

DISCUSSION: Diminishing shower and isolated thunderstorm activity will exit eastern Montana to the northeast this afternoon. Residual MVFR ceilings and localized reduced visibilities at KSDY and KGDV will gradually lift to VFR by late afternoon/early evening as skies clear behind the shortwave. KGGW and KOLF will remain VFR through the period.

WINDS: Easterly winds around 5-10 kts becoming light and variable this evening, then turning southerly under 10kts by Thursday afternoon.

GGW WATCHES/WARNINGS/ADVISORIES

None.