Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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709 FXUS65 KTFX 242323 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 423 PM MST Sun Nov 24 2024 Aviation Section Updated. .KEY MESSAGES... -Low temperatures and wind chills fall to the single digits above and below zero across North-Central Montana for much of this upcoming week, especially along the Hi-line. -Temperatures warm closer near seasonal averages for southwest Montana. -Accumulations from scattered snow showers over the next couple of days will be negligible, though chances for accumulating snow increase heading into the holiday weekend. && .DISCUSSION... /Issued 210 PM MST Sun Nov 24 2024/ - Meteorological Overview: Transient ridging moves into the Northern Rockies tonight into Monday, but warm air advection aloft will maintain cloud cover and chances for light snow for central and north-central areas. Looking ahead, there is a general expectation for a northwesterly flow aloft to persist for most if not all the upcoming week. Passing disturbances initially offer little in the way for appreciable snowfall until a more defined wave moves through Tuesday into Wednesday and brings mostly mountain snow. More shortwaves dive southeastward into the region during the Thanksgiving holiday for lower elevation accumulating snow potential. - Forecast Confidence & Scenarios: Pops were increased to the 20 to 40% range over Central and North- central MT tonight into Monday in response to the expected mid- level warm air advection, but snowfall will be scattered and on the lighter side with minimal impacts. Any patchy fog development tonight and Monday morning should be limited by cloud cover. The northwesterly flow aloft will support a parade of systems that will reinforce the cold air for northern areas. Daily lows in the single digits above and below zero can be expected, especially along the Hi-line. The cold looks to be far more intermittent for central and southwestern areas south of the highway 200 corridor. I did lower temperatures for the normally cooler plains locations to match closer the Canadian model guidance. The probability for one inch of snow of more is only above 40% for mountain areas for the Tuesday/Wednesday system. Then lower elevation snow potential increases during the holiday weekend, when the chance for an inch or more of snow increases to the 30 to 50% each day Thursday through Saturday. - RCG && .AVIATION... 25/00Z TAF Period VFR conditions will prevail across all terminals during this TAF period. However, between 25/06Z and 25/10Z there is a 30% chance for snow at the KCTB terminal which would reduce vsibility to MVFR levels. At the KLWT and KGTF terminals there is a 20% chance for snow between 25/06Z and 25/10Z. Between 25/12Z and 26/00Z there is a 20 - 30% chance for snow at the KHVR terminal. At the KCTB terminal there is a 20% chance for snow from 25/17Z on through the end of the TAF period. There is a 20% chance for fog to form at the KHVR terminal Monday morning. There will be winds gusting up to 26kts during most of this TAF period at the KEKS terminal. During most of this TAF period there will be periods of mountain obscuration in Southwestern Montana. -IG Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 1 28 14 40 / 20 10 10 20 CTB -6 17 7 32 / 30 20 10 10 HLN 13 38 20 40 / 10 0 0 30 BZN 12 37 18 38 / 10 0 10 30 WYS 5 28 9 31 / 20 0 20 70 DLN 13 36 17 35 / 10 0 0 20 HVR -8 11 -1 24 / 20 30 10 30 LWT 5 37 19 41 / 20 0 10 30 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls