textproduct: Great Falls

KEY MESSAGES

- Scattered showers today, especially over North Central MT, otherwise much cooler.

- Another chance for lower elevation rain and mountain snow over the Rockies Sunday into Monday.

- Temperatures start to warm back up by late next week.

DISCUSSION

- Meteorological Overview: A weak upper level disturbance is moving from west to east across North Central MT this morning, producing a few thunderstorms along the divide and scattered showers over the Plains of North Central MT. That trend will continue through the morning hours, before the precipitation starts to diminish this afternoon. Generally quiet conditions expected tonight through Sunday morning, before the next upper level low arrives by Sunday evening. The forecast models have been decreasing precipitation amounts with this system, and also pulling the precip a bit further north. This system exits the region on Monday, with showers decreasing.

For Tuesday through Friday of next week, northwesterly flow aloft develop by Wednesday, as a another upper level disturbance moves southward through the area, producing some scattered showers. This disturbance quickly exits the area by Thursday as an upper level ridge tries to rebuild over the Northern Rockies by Friday. This will result in warmer air moving back into the CWA by next Friday.

- Forecast Confidence & Scenarios: The main concern is how much precipitation falls Sun into Mon and how low do the snow levels get. Overall the forecast models generally have the max QPF of only around an inch over the Northern Rockies. The probability of 1 inch of QPF in Glacier Park is only 60 percent, with less than a 20 percent over much of the northern Plains. Thus snow accumulations look mainly to be in the advisory criteria, of 3 to 7 inches. Snow levels will be slow to fall as well, but could fall down to about 6000 feet or so by Monday morning. It is likely that a winter statement will be needed for the Glacier Park area for this event.

Otherwise, just expect much cooler temperatures over the CWA for the next week or so. That being said, temperatures will be quite a bit cooler over North Central MT compared to Southwest MT, where afternoon temperatures over Southwest MT will still be mostly in the upper 60s and lower 70s yet. Brusda

AVIATION

11/12Z TAF Period

Rain and isolated thunderstorms will affect much of North Central MT this morning, with some IFR conditions expected at times. Conditions improve this afternoon through this evening. There is some fog potential by Saturday morning, just depending on how much drying occurs this afternoon, but the probability is too low to include at terminal sites at this time. Mountains/passes will be obscured at least through mid day over North Central MT. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 58 43 58 40 / 90 10 40 20 CTB 52 39 50 36 / 80 30 40 30 HLN 65 45 64 44 / 70 10 10 30 BZN 71 41 71 40 / 10 20 0 20 WYS 70 30 71 38 / 0 0 0 30 DLN 73 38 73 41 / 0 0 0 20 HVR 64 39 59 37 / 60 10 30 10 LWT 58 40 59 37 / 90 30 20 30

TFX WATCHES/WARNINGS/ADVISORIES

None.