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
011 FXUS65 KTFX 021633 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1033 AM MDT Thu May 2 2024 .SYNOPSIS... A storm system slowly tracking east along the Montana and Saskatchewan border will bring wet snow or snow showers to much of the region today with the most impactful snow looking to fall over the central Montana Mountains. Temperatures rise back toward normal Saturday as ridging builds in before another precipitation producing system arrives late this weekend into next week. && .UPDATE... This morning`s update included lowering today`s maximum forecast temperatures, especially across north central and central Montana. Minor adjustments were made to wind speed and direction, and probability of precipitation was fine-tuned. No further updates are made, at this time. - Fogleman && .AVIATION... 530 AM MDT Thu May 2 2024 (02/12Z TAF Period) MFVR/IFR conditions persist across north-central MT terminals this morning in widespread precipitation with lowest cigs/vis at KGTF and KLWT where some brief LIFR is possible. Widespread precipitation and mountain obscuration continues into this evening across the central MT mountains with scattered to numerous snow showers moving across north-central and central MT terminals and continued periods of MVFR/IFR through this evening. KHLN will see snow showers this afternoon with scattered or less coverage of snow showers south of KBTM to KBZN. Gusty northwest winds develop at most terminals today and persist into this evening before gradually diminishing overnight. Hoenisch Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 530 AM MDT Thu May 2 2024/ Low pressure at the surface roughly co-located beneath a broader mid- upper level low centered over southern Saskatchewan will track slowly east along the International Border today and tonight, maintaining a moist/cyclonic northwesterly flow across the area. An area of widespread precipitation continues to pivot across north- central MT early this morning with an embedded disturbance and lower level boundary supporting an area of moderate precipitation that is expected to sag south into the MT-200/US-87 corridor from Great Falls to Lewistown by around 6 AM. This boundary slowly continues south, reaching the US-12 corridor from Helena to White Sulphur Springs this afternoon before dissipating. Lower to mid level flow turns more northwesterly behind this disturbance, shifting the focus for ongoing widespread precipitation to the central MT mountains and adjacent areas to the north later this afternoon through tonight while cold/cyclonic flow and emebedded disturbances support more showery precipitation coverage elsewhere across north-central and central MT this afternoon into this evening. Precipitation is primarily snow above 3500 ft with winter weather impacts likely to be limited to areas where heavier precipitation rates occur, especially this morning. This includes areas from near Glacier NP, where snow has been falling through the overngiht period, south along the Rocky Mtn Front and east across the MT- 200/US-87 corridor. Winter storm warnings and advisories are in effect for these areas with worst road conditions likely along US-89 NW of Browning and over Kings Hill in the Little Belts. US-87 from Belt to Geyser will also see enhanced snowfall rates this morning with potential for a greater buildup of slush on road surfaces there. One area to watch this afternoon will be Lewis and Clark County where hi-resolution models suggest a greater coverage of convective snow showers will develop. While accumulations on road surfaces are less likely during peak afternoon heating, periods of low visibility in areas of briefly more intense snow could affect travelers there. Snow showers gradually decrease in coverage tonight across lower elevation areas but are likely to persist through much of the overnight period across the Little Belts/Highwoods, Snowies and Bears Paw mountains under continued moist NW flow. A transient/weak upper level ridge develops Friday across the northern Rockies and shifts east across the area Saturday for a brief period of drier weather between the current upper level low affecting the region and the next one moving onto the west coast this weekend. Temperatures warm some on Friday but remain below seasonal averages with widespread overnight low temperatures likely to fall below freezing under lighter winds and clearing skies Friday night before a seasonably mild and dry day on Saturday. Multi-model ensembles are in broad agreement to take the next next upper level low eastward into the Great Basin by Sunday with southerly flow ahead of this feature importing warmer air and moisture into the region on Sunday. This will bring an increased risk for showers as well as thunderstorms from south to north across the area Sunday afternoon and evening with confidence in timing and additional details decreasing by early next week, though an overall pattern featuring above average precipitation chances is likely, especially for eastern portions of north- central MT. Hoenisch && .PRELIMINARY POINT TEMPS/POPS... GTF 39 30 50 26 / 90 70 40 0 CTB 37 29 51 26 / 90 80 10 0 HLN 47 32 57 31 / 80 40 20 0 BZN 48 26 53 28 / 40 20 10 0 WYS 42 19 48 20 / 20 30 10 0 DLN 49 28 55 30 / 10 30 0 0 HVR 40 29 51 27 / 90 50 30 0 LWT 35 26 44 23 / 90 60 50 0 && .TFX WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until noon MDT today for East Glacier Park Region. Winter Weather Advisory until noon MDT today for Cascade County below 5000ft-Judith Basin County and Judith Gap-Northern High Plains-Southern Rocky Mountain Front. Winter Weather Advisory until 6 AM MDT Friday for Bears Paw Mountains and Southern Blaine. Winter Storm Warning until 6 PM MDT this evening for Little Belt and Highwood Mountains. Winter Weather Advisory until 6 PM MDT this evening for Big Belt, Bridger and Castle Mountains-Snowy and Judith Mountains. && $$ http://www.weather.gov/greatfalls