textproduct: Great Falls

KEY MESSAGES

- Dry, warm, and windy conditions set up tomorrow, bringing elevated to critical fire weather conditions.

- A Pacific system will continue mountain snow/rain and isolated light lower elevation rain through Thursday.

- Gusty winds will develop along the Hi-line and Southwest MT today.

- Dry and warm weather is on tap for the weekend.

DISCUSSION

- Meteorological Overview:

Weak troughing moving inland from the Western U.S coast will continue to advect in Pacific moisture to the region. With this trough arrives better better winds aloft to the region, particular to the Rocky Mountain Front and Hi-line this morning. This stronger jet lasts into the afternoon, where daytime mixing along with a cold front will help mix these stronger winds down to the surface. Across Southwest MT, a strong pressure gradient developing throughout the day Wednesday will result in stronger winds. Strong winds decreases diurnally in the evening. The combination of the warm, dry, and windy conditions will create elevated to critical fire weather conditions, especially in Southwest MT.

The core of upper-level shortwave arrives late tonight into Thursday, which will bring slight chances for light rain/snow. A cold front passage will bring a brief relief in warmer temperatures Thursday. Upper-level ridging builds back into the weekend, resulting in warmer and drier condtions to move back in. Ensembles are hinting a bit of a pattern change next week, bringing in cooler temperatures and more moisture for lower elevations.

- Forecast Confidence & Scenarios:

Winds Today:

The area with highest confidence in getting high winds is the Cut Bank to Sweet Grass Hills area, where the 700mb jet peaks at ~75kts Wednesday morning. Farther east along the Hi-line, the 700mb jet is slightly less, but a 60-70kt jet will try to mix down isolated gusts of 60 mph during the day. The high winds are more marginal in Southwest MT. However, the combination of the cold front passage and pressure gradient front will try to mix down a few isolated 60 mph wind gusts as well. Therefore, no changes were made to the current High Wind Warnings.

Mountain Snow this Evening Through Thursday:

With the cold front passage today, snow levels will drop back down to pass level tonight into Thursday. Warm road temperatures will make snow struggle to accumulate initially. This combined with light moisture amounts will keep snow accumulations on passes light (up to 1-2"). -Wilson

AVIATION

25/12Z TAF Period.

Light rain will affect the Rocky Mountain Front through the period. Expect gusty winds to develop this morning over portions of North Central and Southwest MT. Some blowing dust could also be an impact, reducing visibility at times. More widespread light rain/snow to affect Central and Southwest MT after 00z Thu. Mountains/passes will be obscured at times across the CWA through the period. Brusda

FIRE WEATHER

Warm, dry, and breezy to windy conditions are expected area wide Wednesday, with the strongest winds likely to be found along the US 2 Corridor and a second maxima across Southwestern Montana. Southwestern Montana will see RH values dipping into the upper teens as temperatures climb into the mid to upper 60s. Critical fire weather conditions are expected to develop across Southwest MT this afternoon, which will create rapid growth in any new wildfire starts.

Winds will weaken after sunset, but a cold front will push through the area from the north during the evening and overnight hours, bringing a wind shift to the north. Some light precipitation is expected, mainly over the higher terrain with this frontal passage, but is not expected to produce much moisture on the fine fuels across the plains. The cold front will also bring in cooler temperatures Thursday, which will bring some relief to the elevated fire weather risk. Ludwig/Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 61 29 45 23 / 10 10 10 0 CTB 52 17 38 17 / 0 20 10 0 HLN 62 29 46 23 / 40 30 0 0 BZN 70 30 49 19 / 10 50 20 0 WYS 60 29 47 11 / 20 30 20 0 DLN 67 32 49 22 / 10 20 0 0 HVR 62 22 38 17 / 10 10 20 0 LWT 62 28 41 20 / 30 50 20 0

TFX WATCHES/WARNINGS/ADVISORIES

High Wind Warning until 6 PM MDT this evening for Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty.

High Wind Warning from 9 AM this morning to 7 PM MDT this evening for Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Gallatin Valley-Gallatin and Madison County Mountains and Centennial Mountains-Hill County- Madison River Valley-Missouri Headwaters-Northern Blaine County- Ruby Mountains and Southern Beaverhead Mountains.

Red Flag Warning from noon today to 7 PM MDT this evening for Helena and Townsend Ranger Districts of the Helena National Forest.