textproduct: Great Falls

KEY MESSAGES

- Coldest temperatures of the winter so far will remain through Monday morning with this afternoon through Sunday morning being the coldest.

- Another system will bring widespread snowfall to the area Tuesday through Wednesday.

- Monday through the end of the work week it will warm up.

DISCUSSION

- Meteorological Overview:

This afternoon an upper-level ridge will briefly move over North- central, Central, and Southwestern Montana. It will be cold and mostly dry this afternoon with isolated light snow across Southwestern Montana late this afternoon through tonight. Due to clearing skies tonight plus any melting snow fog is possible across North-central Montana see the Forecast Confidence & Scenarios Section for details. On Sunday an upper-level trough briefly moves over North-central, Central, and Southwestern Montana. This will bring another day of cold temperatures to the area with the coldest temperatures of the year expected Sunday morning. Due to a surface high exiting the area on Sunday it will be slightly warmer in the afternoon than this afternoon. On Monday an upper-level ridge moves over North-central, Central, and Southwestern Montana. This will allow temperatures to warm up with mostly dry weather.

On Tuesday an upper-level trough will move over North-central, Central, and Southwestern Montana. This will bring snow to North- central, Central, and Southwestern Montana. On Wednesday the upper- level trough remains over North-central, Central, and Southwestern Montana. Snow will linger across the area on Wednesday. On Thursday and Friday an upper-level ridge builds in over North-central, Central, and Southwestern Montana this will allow temperatures to warm up some more with mostly dry weather. IG

- Forecast Confidence & Scenarios:

Across the plains of North-central Montana there is a 25 - 50% chance for fog to form. The areas most susceptible to fog formation are the milk river valley and any area where any snow melts.

Sunday morning there is greater than a 50% chance for subzero temperatures across all of North-central Montana. Sunday morning across the Milk River Valley there is greater than a 70% chance for temperatures of 10 below zero or lower. Monday morning across the Milk River Valley there is greater than a 60% chance for subzero lows. On Sunday there is greater than a 50% chance for highs of 15 degrees or colder across North-central Montana north of a Great Falls to Lewistown line. As a result a Cold Weather Advisory was issued for Hill and Northern Blaine County from tonight through Monday morning. IG

AVIATION

29/18Z TAF Period

VFR conditions with mainly clear skies and light surface winds prevail through this afternoon. A weather disturbance moving across Idaho will spread mid-high clouds across SW MT this evening with some mountain obscuration light snow showers possible as far north as KDLN to KEKS. Fog development is a concern on the plains tonight with most model guidance suggesting its development from KHVR west to KCTB and KGTF. Hoenisch

PRELIMINARY POINT TEMPS/POPS

GTF -7 23 7 33 / 0 0 0 0 CTB -11 18 7 30 / 0 0 0 0 HLN 4 25 9 33 / 0 0 0 0 BZN 3 23 4 31 / 10 10 0 0 WYS 2 28 0 25 / 20 10 0 10 DLN 14 28 10 35 / 30 10 0 0 HVR -22 3 -10 26 / 0 0 0 0 LWT -4 23 7 34 / 0 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory from 6 PM this evening to 10 AM MST Monday for Hill County-Northern Blaine County.