textproduct: Great Falls

KEY MESSAGES

- Today it will be cool with a warm up expected for the middle of this week.

- Today through Wednesday there will be periods of primarily mountain snow showers with light snow this morning in the valleys of Southwestern Montana.

- Thursday and Friday it will be warm and dry with precipitation returning for the weekend.

DISCUSSION

- Meteorological Overview:

On Monday the upper-level trough remains over North-central, Central, and Southwestern Montana, but the upper-level low has moved east of Montana. This will allow temperatures to warm up slightly. However there will be snow showers in the mountains of North- central, Central, and Southwestern Montana today. The heaviest snow will be in the Mountains of Southwestern Montana and the Little Belts. This morning there will also be light snow in the valleys of Southwestern Montana. Monday afternoon due to the warmer temperatures there will be isolated rumbles of thunder in Southwestern Montana. On Tuesday northwest flow aloft remains over North-central, Central, and Southwestern Montana. This will allow temperatures to warm up to near seasonal averages with mountain snow showers and isolated snow showers in lower-elevation northwesterly upslope favored areas. On Tuesday there will be isolated rumbles of thunder in Central Montana due to the warmer temperatures.

On Wednesday an upper-level ridge begins to approach Montana with northwest flow aloft over North-central, Central, and Southwestern Montana. This will keep temperatures around seasonal averages. There will be another day of mountain showers with isolated lower- elevations seeing snow showers in northwesterly upslope favored areas. Due to the warm temperatures of Wednesday there will be isolated rumbles of thunder across Central and Southwestern Montana. Thursday through Friday an upper-level ridge gradually moves over North-central, Central, and Southwestern Montana. This will allow temperatures to gradually warm up with mostly dry weather. Saturday through Sunday an upper-level trough begins to move over Montana. This will bring cooler temperatures and more widespread precipitation to North-central, Central, and Southwestern Montana. -IG

- Forecast Confidence & Scenarios:

Across much of North-central Montana tomorrow morning there is greater than a 50% chance for low temperatures of 20 degrees or colder. Along the Hi-Line this morning there is a 40 - 70% chance for low temperatures of 15 degrees or colder. Along the Hi-Line this morning there is a 20 - 50% chance for wind chills of 10 degrees or colder. Today there is a 50 - 80% chance for 1 inch of snow across the Little Belts and mountains of Southwestern Montana.

Today there is a 10 - 15% chance for thunder in Southwestern Montana. On Tuesday there is a 15% chance for thunder in Central Montana. On Wednesday there is a 15% chance for thunder in Central and Southwestern Montana. -IG

AVIATION

27/06Z TAF Period

Scattered snow showers will continue to affect portions of the CWA through the period. The most likely area today will be far Southwest MT along the ID/MT border from Monida Pass to West Yellowstone. As you go north, the chances for snow showers decrease. Also, clouds will begin to thin out along the Highway 2 corridor from Cut Bank to Havre. Mountains/passes will be obscured across the CWA by clouds through the period. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 36 19 49 27 / 90 30 20 10 CTB 30 10 46 23 / 90 10 10 0 HLN 40 24 50 28 / 40 30 40 10 BZN 46 24 47 23 / 20 40 50 20 WYS 46 20 44 18 / 60 60 70 40 DLN 49 26 48 26 / 30 50 60 20 HVR 38 17 48 24 / 50 0 10 0 LWT 36 19 42 23 / 50 50 40 10

TFX WATCHES/WARNINGS/ADVISORIES

None.