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
395 FXUS65 KTFX 221527 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 927 AM MDT Sun Sep 22 2024 .SYNOPSIS... Westerly winds increase today while temperatures warm closer to average. An approaching weather system will increase middle and higher level clouds by this afternoon before bringing isolated lighter end shower activity tonight into early Monday. Much warmer and dry conditions are expected for Tuesday and Wednesday. && .UPDATE... Increasing westerly to northwesterly flow aloft will result in a pressure gradient developing over the plains through the day today and tonight. Breezy westerly winds will be the theme today across the plains as a result, with at least a light wind persisting tonight out of the west. A weak wave passing through this increasing westerly to northwesterly flow tonight will bring a narrow window for a few showers late tonight into early tomorrow across Central and North-central Montana. The only change to the forecast this morning was to increase winds a bit in areas where winds have developed already this morning. -AM && .AVIATION... 22/12Z TAF Period VFR conditions are forecast to continue across North Central (KCTB, KHVR), Central (KLWT, KGTF, KHLN), and Southwest (KBZN, KEKS, KWYS) Montana through at least 23/12Z. Patchy fog may still form between 12Z and 16Z in some Southwest and Central Montana valleys, but high cloudiness will keep the probability low for significantly reduced visibility at any of those terminals. High- and mid-level cloudiness will increase over the area in the increasing west-northwest flow aloft through around 00Z; any precipitation that falls out of the clouds will likely not reach the ground. As the flow aloft increases, the potential for mountain wave turbulence increases as well. Westerly downslope winds will also become gusty after 15Z as well, with the areas of potential 30+ kt gusts being limited to along and west of a KCTB-KGTF line. These winds should start to decouple a bit after 02Z, allowing areas of low level wind shear to develop. -Coulston Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 532 AM MDT Sun Sep 22 2024/ Mostly clear skies are being observed early this morning aside from some passing cirrus and the ongoing potential for AM patchy fog development for some of the wind protected valleys. Westerly winds are already increasing along the Rocky Mountain Front and this will spread onto the plains later today. There is over a 70% chance for gusts to exceed 40 mph along the Northern Rocky Mountain Front eastward toward the Cut Bank area; otherwise, most other Central/North-central locations should see gusts more in the 15 to 30 mph range. Middle and higher level cloudiness will be on the increase today as a Pacific shortwave approaches from the northwest. This system is much weaker than last Friday`s, but it will still bring some lighter end shower activity, mostly for Central/North- central MT this evening through early Monday. Temperatures moderate to near average toady and nearly hold steady on Monday. High pressure aloft builds in Tuesday and Wednesday for dry and very warm conditions. Most lower elevation temperatures will peak in the lower and middle 80s Wednesday afternoon, about 15 to 20 degrees above average for this time of year. Most record highs for Wednesday run from the upper 80s for the cooler southwest valleys to the lower and middle 90s over the warmer central/north-central areas, so widespread record breaking temperatures are not expected at this time. Most ensembles bring a trough onto the Pacific NW coast on Wednesday before brushing the Northern Rockies on Thursday for a slight cool down, breezy to windy conditions, and perhaps a few showers or thunderstorms. Temperatures still remain above average until the next cold front arrives around Saturday and brings more seasonable conditions. The next chance for more widespread precipitation looks to hold off until next Sunday/Monday or even beyond. - RCG && .PRELIMINARY POINT TEMPS/POPS... GTF 75 46 73 45 / 10 20 0 0 CTB 69 43 69 46 / 0 10 0 0 HLN 75 50 73 46 / 0 10 0 0 BZN 71 43 70 40 / 0 10 0 0 WYS 67 31 64 30 / 0 10 0 0 DLN 72 41 68 39 / 0 10 0 0 HVR 71 47 71 45 / 0 10 0 0 LWT 70 45 67 42 / 0 10 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls