textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Saturday through Monday: A slow moving weather system will bring prolonged, moderate to heavy rainfall, focused along the divide and in Glacier Park region.

- River, stream, and creek rises from widespread rain and snow melt, leading to the potential minor flooding.

- Snow levels fall near 7000-7,500 feet tonight into Sunday morning, cold, wet and raw conditions.

Key forecast update from last issuance, models have continued their trend towards less precipitation. Hydro concerns remain but are diminishing in most locations except Flathead and Lake Counties. That said, any poor drainage area could see ponding of water after a heavier shower this weekend.

While models are trending drier the Northern Rockies is still on track for a long duration precipitation event through Tuesday morning. The focus remains along US-93 and eastward, especially areas north of Flathead Lake including Glacier National Park. South of I-90, most of the precipitation will fall before Sunday afternoon, thereafter expect light showers, overcast skies, and cooler temperatures. The main focus of precipitation will be Flathead, Lake, Granite, Silver Bow, and Powell Counties. These locations have a 70 to 80% probability of receiving a 0.50" or more of precipitation by Tuesday morning. Higher terrain of the Mission and Flathead mountains, and the mountains along the Continental Divide have a 40 to 70% chance of receiving 1.50" or more of precipitation. Above 7000' that precipitation will mix with wet snow creating cold, wet, and raw conditions.

AVIATION

The latest radar and satellite images are showing the numerous showers developing into a shield of stratiform precipitation across western Montana this afternoon. This swath of precipitation will steadily fill in this evening and linger over the region into Sunday. KGPI, KMSO and KBTM are expected to be under this precipitation throughout the night. While KHRF and KSMN will be on the edge, so they will have periods without steady precipitation. The precipitation could end around sunrise for KBTM, which could lead to the development of fog. Steady rain and low clouds will cause obscured terrain throughout the forecast period, especially for western Montana.

MSO WATCHES/WARNINGS/ADVISORIES

MT...Flood Watch from 6 PM MDT this evening through Monday morning for Flathead/Mission Valleys...West Glacier Region.

ID...None.