Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
635 FXUS65 KTFX 081704 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1004 AM MST Fri Nov 8 2024 Aviation Section Updated. .KEY MESSAGES... - It will be warm today and Saturday before it cools down slightly on Sunday and then warms back up on Monday. - It will be windy across the area Monday through Wednesday with cooler temperatures on Tuesday and Wednesday. - Precipitation will return to the Rocky Mountain Front and Southwestern Montana on Sunday, with higher amounts expected Monday evening through Wednesday evening. && .DISCUSSION... /Issued 834 AM MST Fri Nov 8 2024/ UPDATE... An upper level ridge of high pressure remains centered across the Northern Rockies and MT with satellite imagery showing just some scattered mid-hi level clouds spilling over the ridge along the Rocky Mtn Front. Dry and milder than average conditions are on track across the area this afternoon with no significant updates to the forecast this morning. Hoenisch - Meteorological Overview: There is an upper-level ridge in place over North-central, Central, and Southwestern Montana through Saturday this will bring warm (well above seasonal average) temperatures and clear skies to the area through Saturday. Due to clear skies and light winds tonight through this morning fog will likely form in some of the valleys of Southwestern Montana especially the West Yellowstone area and Gallatin valley. Today due to a strong surface pressure gradient there will be breezy conditions along the Rocky Mountain Front. On Sunday a weak upper-level shortwave quickly moves through the area which will bring precipitation along the Continental Divide and in the Gallatin and Madison ranges for Sunday and Monday. Additionally high temperatures on Sunday will be slightly cooler due to the shortwave. On Monday an upper-level ridge builds back in over North- central, Central, and Southwestern Montana which will warm temperatures back up to well-above seasonal averages. Monday evening an upper-level trough associated with a surface cold front begins to move through North-central, Central, and Southwestern Montana. This combined with a strong surface pressure gradient will bring strong winds to the area especially along the Rocky Mountain Front Monday through Wednesday. On Tuesday and Wednesday the upper-level trough remains over North-central, Central, and Southwestern Montana until Wednesday evening. This will bring cooler (about seasonal average) temperatures to the area with precipitation chances along the Rocky Mountain Front and south of the Montana Highway 200 Corridor. To close out the work week the upper-level ridge remains over North-central, Central, and Southwestern Montana. This will dry out the area and warm temperatures back up for Thursday and next Friday. - Forecast Confidence & Scenarios: There is high forecast confidence in dry and warm weather through Saturday and light precipitation along the Continental Divide and the Gallatin and Madison ranges with cooler temperatures on Sunday. However the location and track of the upper-level shortwave that brings the precipitation on Sunday varies between models and ensembles so as result there is some uncertainty in the precipitation amounts. On Sunday there is a 40 - 70% chance for greater than trace of liquid precipitation and a 50 - 80% chance for greater than a tenth of an inch of snow along the Rocky Mountain Front and the Gallatin and Madison ranges. Today, Saturday, and Monday there is a 40 - 70% chance for temperatures of 60 degrees or greater across the plains of North-central Montana. On Monday there is low confidence in the timing of the upper-level ridge breaking down and the strength of the upper-level trough with high confidence that the upper-level ridge will break down with an upper-level trough replacing it. This results in uncertainty in the wind speeds and gusts and how much colder temperatures will get Monday through Wednesday. On Monday, Tuesday, and Wednesday there is a 40% chance for wind gusts greater than 45 mph across North- central, Central, and Southwestern Montana. On Monday, Tuesday and Wednesday there is a 30 - 60% chance for wind gusts of greater than 55 mph along the Rocky Mountain Front and Adjacent Plains. Monday evening through Wednesday morning there is a 50 - 80% chance for greater than a tenth of an inch of liquid precipitation south of the Montana Highway 200 Corridor. Monday evening through Wednesday evening there is a 50 - 80% chance for 2 inches of snow or greater along the Rocky Mountain Front and the mountains of Southwestern Montana. Clusters show high confidence in an upper-level ridge building in over the area on Wednesday and keeping it over the area on Thursday. On next Friday clusters begin to show an upper-level ridge moving toward North-central, Central, and Southwestern Montana but there are differences in the timing and strength of the trough. - IG && .AVIATION... 08/18Z TAF Period VFR conditions persist at all TAF sites as the area remains beneath an upper level ridge of high pressure with just a gradual increase in mainly high level clouds later today through Saturday morning. Hoenisch The KWYS TAF will not be issued until airport operations resume next spring. Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 62 35 58 40 / 0 0 0 0 CTB 63 34 57 33 / 0 0 0 10 HLN 54 28 55 33 / 0 0 0 10 BZN 52 24 54 28 / 0 0 0 10 WYS 45 13 42 18 / 0 0 0 10 DLN 52 25 53 29 / 0 0 0 0 HVR 60 30 55 33 / 0 0 0 0 LWT 61 33 58 33 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls