textproduct: Great Falls

KEY MESSAGES

- Showers and thunderstorms expected each afternoon through next week, save for Independence Day. - Temperatures gradually warm up through the middle of next week. - Breezy this weekend.

DISCUSSION

- Meteorological Overview:

Westerly to southwesterly flow aloft will continue over the next few days, bringing above average temperatures through the weekend and near daily chances for some isolated to scattered showers and/or thunderstorms. The exception to this trend will be Independence Day, when upper level ridging to our south tries to nudge into the area, which will prevent showers from developing. While showers and storms will fail to initiate on Saturday, it will be a bit on the gusty side as a lee trough develops in Southern Alberta and upper level flow picks up a bit, which will allow for wind gusts to reach 25-30 mph across much of Southwestern and North Central Montana Saturday afternoon and evening.

Winds remain gusty on Sunday as the upper level height gradient over Montana remains tight as the broad trough to our north remains juxtaposed with the ridge to our south. This setup, combined with some moisture working in along the west side of the ridge, will allow for some showers and storms to develop, and given the dry and deep boundary layer, I cant rule out some gusty outflow winds with any showers and thunderstorms. Overall, the pattern will remain fairly stagnant through Wednesday, until a more potent upper level trough will sweep through southern British Columbia and Alberta, which will result in more widespread showers and thunderstorms and bring temperatures closer to average, even if still slightly warmer than average.

- Forecast Confidence & Scenarios:

Winds Saturday and Sunday: There is fairly good agreement in mid level winds increasing Saturday as upper level ridging to our south expands northward, intruding upon the broad upper level trough over Southern British Columbia and Alberta. This will cause mid and upper level winds to accelerate, and clear skies will allow for efficient thermal mixing in the boundary layer, which will allow these winds to mix to the surface from time to time, especially in the mid to late afternoon and through the evening. Overall wind gusts should be a bit weaker Sunday, thanks to some afternoon cloud cover, though convective showers and thunderstorms may mix these wind gusts down and their outflows may cause some local enhancement.

Thunderstorms next week: Increasing surface temperatures this week across the area and our position on the northern edge of the upper level ridge to our south will create a favorable environment for daily showers and thunderstorms next week. Warmth, along with some periodic surges in lower level moisture will allow for relatively high instability across the area. Combined with some periods of favorable wind profiles, a few of the storms could become strong to severe with gusty winds and/or hail any day next week. Ludwig

AVIATION

03/06Z TAF Period

General VFR conditions will prevail through the TAF period under passing variable cloudiness; however, there will be a few isolated showers and thunderstorms between 03/18 and 04/00Z, mostly impacting the KLWT area. - RCG

HYDROLOGY

A flood advisory will continue for recreation areas until further notice for the Many Glacier area in Glacier National Park, as flood waters slowly recede. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 81 52 86 55 / 0 0 0 0 CTB 75 50 80 50 / 0 0 0 0 HLN 80 52 85 55 / 20 20 0 0 BZN 79 49 84 53 / 20 20 0 0 WYS 74 40 80 43 / 20 20 0 0 DLN 77 48 83 51 / 20 20 0 0 HVR 82 53 86 56 / 0 0 0 0 LWT 77 49 83 52 / 20 20 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.