textproduct: Great Falls

KEY MESSAGES

- Light rain and snow showers this morning will generally diminish this afternoon.

- There is a small chance for mostly a passing mountain rain or snow shower Wednesday through Saturday, with a better chance for a more widespread rain or snow on Sunday.

- Afternoon temperatures will mostly be just a bit below normal for most areas over the next few days.

DISCUSSION

- Meteorological Overview: The upper level disturbance that is producing all the rain/snow this morning continues to move eastward, and should exit the eastern portions of the CWA this afternoon. Thus morning showers are likely, especially over North Central MT, with showers ending this afternoon for most areas.

For the next several days, the flow aloft will shift to a more westerly flow. This is a bit of a change from previous forecasts. Thus with a more westerly flow, the chances for precipitation will be confined mainly to our western mountains, with just a small chance for an isolated shower east of the divide.

The next more widespread weather system looks to arrive Sun into Mon, as a fairly strong upper level low moves from WA southeastward towards UT. This will result in a period of rain/snow showers moving through our CWA as the disturbance passes to our south.

With the westerly flow aloft, afternoon temperatures will be close to seasonal normals, or just a touch below for most areas over the next few days.

- Forecast Confidence & Scenarios: Snow will fall over the Rocky Mountain Front today, mostly for elevations above 5000 feet. The best accumulating snow will fall over the northern Rockies with a few inches expected today. Since Logan's Pass is closed, no advisory will be issued at this time. Should impacts start to develop on Marias Pass, a winter weather advisory might be needed for a short time.

For this weekend, snow amounts of 3 to 6 inches are in the current forecast for the mountains around Big Sky, Bozeman and northward to Kings Hill. Thus a winter statement might be needed this weekend for some mountain ranges.

Looking ahead to the middle of next week, so forecast models are showing more of an upper level ridge, rather than a westerly flow aloft. Should the upper level ridge pan out, afternoon temperatures could be a few degrees warmer than currently forecast. Brusda

AVIATION

27/12Z TAF Period

Light rain/snow will affect North Central MT into this afternoon, with showers decreasing over Southwest MT this morning. Low ceilings and mountain obscured will affect much of the CWA through today. However, expect precipitation to continue along the divide through tonight, along with low ceilings and mountain obscurations in that region. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 50 36 51 30 / 30 0 0 10 CTB 46 29 43 23 / 30 0 0 30 HLN 49 25 49 24 / 0 10 10 0 BZN 47 24 48 23 / 0 10 0 0 WYS 38 18 37 14 / 40 20 10 0 DLN 45 23 44 23 / 0 0 0 0 HVR 50 28 48 22 / 80 10 0 10 LWT 48 30 50 28 / 40 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.