textproduct: Great Falls

KEY MESSAGES

- Creeks and streams emanating from the Rocky Mountain Front will continue to run near bankfull through the middle of the work week.

- A good chance for showers/thunderstorms from Wednesday night through Thursday

- Temperatures warm on Saturday but cool a bit for Sunday, with scattered showers/thunderstorms both days.

DISCUSSION

- Meteorological Overview:

The slow moving upper level disturbance that has brought rain to much of the Northern Rockies since the weekend will continue to pull away from the region through tonight, with rain decreasing from south to north across Central and North Central Montana. Areas that see clearing during the overnight hours will have the potential for fog development.

For Wednesday, the upper level low is going to slowly start to pull away, thus showers will be ending, with temperatures starting to climb back towards normal for most areas.

On Thursday, the next upper level trof approaches. This trof is now progged to move through the CWA a bit earlier in the day. This will keep the threat for stronger storms to mainly just the far eastern portions of the CWA. Otherwise, there will be a good chance for showers/thunderstorms across the CWA as the trof moves through.

For Friday through Sunday, a southwesterly flow aloft will reside over the CWA for Fri/Sat...resulting in warm temperatures and a chance for mostly late day thunderstorms on Sat. On Sunday, a few showers/thunderstorms will be around, along with cooler temperatures.

For Mon/Tue of next week, the forecast models differ, with one model having a brisk westerly flow, while another model has another upper level low moving through the CWA. Thus confidence is low in the forecast for early next week at this time.

- Forecast Confidence & Scenarios:

For Thursday, the potential for severe storms looks to be limited to just the far eastern portions of the CWA, as the upper level trof is now progged to move through the CWA a bit earlier in the day. Brusda

AVIATION

02/18Z TAF Period

IFR/MVFR/low-VFR conditions will prevail across the terminals of Central and North Central Montana through much of the next 24 hours, with rain continuing over or near the KCTB, KHVR, KGTF, and KLWT terminals through 00-06z. Further south across the KHLN, KBZN, KEKS, and KWYS terminals low-VFR/VFR conditions are expected.

HYDROLOGY

A flood advisory remains in effect for portions of Glacier County. Generally it is the southwestern portion of the county. 2 to 3 inches of rainfall have fallen in the area over the past few days, with up to another inch possible by later today.

The main concern right now is Badger Creek and Two Medicine River south of Browning. Both streams are near/at bankful and water could start going over its bank at any time.

Further north, the St Mary River from Babb to US/Canadian border continues to rise, but it is expected to remain below flood stage, thus no statement will be issued at this time for this river.

Elsewhere, Cascade, Teton and Pondera counties reported no flooding as of early this morning. Some creeks are near bankful, but are not expected to exceed bankful at this time, thus no flood statements for these counties at this time. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 43 68 46 69 / 20 20 30 60 CTB 39 65 43 68 / 20 20 10 40 HLN 43 74 50 69 / 20 20 50 60 BZN 36 75 45 70 / 10 10 50 50 WYS 29 70 37 66 / 10 0 10 20 DLN 36 75 46 70 / 10 20 50 20 HVR 42 67 41 72 / 40 20 10 40 LWT 40 66 42 66 / 20 20 30 80

TFX WATCHES/WARNINGS/ADVISORIES

None.