textproduct: Great Falls

KEY MESSAGES

- Warm and dry conditions continue through Friday, with today being the hottest day.

- Warm, breezy, and dry conditions today will bring elevated fire weather.

- Confidence is increasing for cooler and wetter weather Saturday through the beginning of next week.

DISCUSSION

- Meteorological Overview:

Upper-level ridging continues to be the dominating pattern through Friday. This pattern will continue to bring warm and dry weather through the work week. Today will be the warmest day of the week, with high temperatures reaching 15 to 20 degrees above normal. The ridge flattens out today, increasing westerly flow aloft. These increased winds mixes down to the surface, bringing breezy to windy conditions. The combination of the unseasonably warm temperatures, winds, and relative humidity dropping to the teens result in elevated fire weather conditions for today.

A pattern change is forecasted Saturday through at least Monday. An trough moving down from British Columbia beginning Saturday will bring a cooler and wetter pattern. This trough will usher in much colder air into the region, decreasing snow levels. Ensembles have been hinting at the possibility of snow levels decreasing to lower elevations. Timing, how cold it gets, and overall precipitation amounts vary a lot with each model run, so lots of uncertainty exists with this next incoming weather system.

- Forecast Confidence & Scenarios:

Fire Weather This Week:

Fuels are still curing, which limits the risk for critical fire weather conditions today. However, after today, fuels will become more susceptible for fire growth after the prolonged warming and dry period this week. With the ridge flattening again Friday, we will have to monitor for elevated fire weather conditions.

Next Incoming Weather System:

There remains model variability with how cold it gets this weekend and how much precipitation falls. About half of the ensemble members of both the GFS and European models show snow reaching the lower elevations. There's a 30-60% chance for 1" of snow across lower elevations and a 20-50% chance for 3" of snow. Considerable variations in models runs still leave details uncertain, but we will watch on how this system trends throughout the week. -Wilson

AVIATION

05/06Z TAF Period.

VFR conditions prevail through the TAF period with mainly clear skies tonight giving way to some variable high-level clouds on Monday. Local instances of mountain wave turbulence and low level wind shear are possible near terrain later tonight through Monday morning as mid-level westerly flow across the Rockies increases. Surface winds from the southwest increase at TAF sites on the plains Monday morning with most locations having a period with surface gusts around 20-30 kts Monday afternoon before winds diminish again Monday evening. Hoenisch

PRELIMINARY POINT TEMPS/POPS

GTF 79 53 84 51 / 0 0 0 0 CTB 73 48 76 45 / 0 0 0 0 HLN 78 48 83 47 / 0 0 0 0 BZN 78 46 81 45 / 0 0 0 0 WYS 74 36 76 36 / 0 0 0 0 DLN 80 46 82 46 / 0 0 0 0 HVR 75 45 82 46 / 0 0 0 0 LWT 79 54 83 50 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES