textproduct: Great Falls

KEY MESSAGES

- Scattered light precipitation to taper off by late this morning.

- Gusty winds today across North-Central and Central MT, with general breeziness across Southwest MT. - Warm, dry and occasionally breezy throughout the rest of the work week, with potential for record highs.

- Gradual cooling trend this weekened, with chances of precipitation returning across the southern half of the CWA.

DISCUSSION

- Meteorological Overview:

This morning, a shortwave trough is moving through Montana, pushing out the previous zonal flow aloft to the east. This will cause a tightening pressure gradient, both at the surface and in the upper levels of the atmosphere, causing gusty winds across Central and North-Central MT. 700 mb winds look to average across the models around 60 kts, and while diurnal heating may allow some stronger winds aloft to mix down to the surface, cross-sectional analyses does not support the peak 700 mb winds to consistently mix down. As such, while winds will be gusty throughout the day, we are not expecting them to reach high wind criteria. Winds will decrease this evening as the shortwave trough moves east and out of the CWA.

On Wednesday, a strong ridge of high pressure begins to build to the west, gradually moving eastward through Montana until its axis is centered over the Montana/Dakota border by Friday afternoon. This will allow for warm temperatures, dry conditions, and occasional breeziness across the CWA throughout the rest of the work week. In fact, it will get so warm that there will be the potential for record highs. Wednesday through Friday, the majority of Central and North/Central MT will see highs in the mid to upper 60s, with the valley locations of Southwest MT seeing highs in the mid 50s to low 60s.

By Saturday, a large upper level trough will push the ridge eastward as it makes its way east across the Pacific Coast, putting us in southerly flow aloft. This will allow temperatures to begin a gradual cooling trend. Increased chances of precipitation will spread across the southern half of the CWA this weekend as a surge of upper level moisture gets carried along by the aforementioned trough. There is still a decent amount of uncertainty with how this trough will progress this weekend, as only about 60% of models show the CWA under strong influence of the trough on Sunday. -Dzomba

- Forecast Confidence & Scenarios:

The strongest winds today will be along the Rocky Mountain Front, particularly along the immediate eastern slopes, where gusts around 60 MPH will be common. Across the more wind prone areas of the Front, gusts in excess of 75 MPH cannot be ruled out. The probability of a gust greater than 75 MPH around Browning still only peaks at around 20%.

Fergus, Judith Basin, Meagher and Cascade Counties will see the second strongest winds, with gusts 45-50 MPH. A few isolated gusts of high wind criteria (58+ MPH) are possible, but are still too isolated to warrant any high wind warnings. The rest of Central/North-Central MT will see gusts around 35 MPH, while southwest MT will only see general breeziness with gusts around 25 MPH. -Dzomba

AVIATION

10/06Z TAF Period

VFR conditions will prevail through the TAF period. As the next disturbance arrives, low and mid-level clouds will increase through the overnight hours, particularly along the Continental Divide with mountain obscuration possible between 10/06Z and 10/18Z. Precipitation is generally expected to stay within the vicinity of the mountains across Central and Southwest Montana, however, an isolated shower cannot be ruled out across the plains and lower elevation valleys of Southwest Montana. Winds will increase out of the south initially after 10/10Z and veer to the west by the mid morning with gusty conditions expected across the region through 11/06Z. -thor

PRELIMINARY POINT TEMPS/POPS

GTF 58 43 66 43 / 20 0 0 0 CTB 53 40 62 40 / 10 0 0 0 HLN 56 37 59 33 / 10 0 0 0 BZN 56 33 60 32 / 10 0 0 0 WYS 46 24 49 23 / 0 0 0 0 DLN 56 32 57 31 / 0 0 0 0 HVR 60 36 67 38 / 20 0 0 0 LWT 56 37 66 40 / 20 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

None.