Scientific Forecaster Discussion
000 FXUS65 KBYZ 261032 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 432 AM MDT Tue Sep 26 2017 .SHORT TERM...valid for Tdy and Wed... A few days of pleasant mild weather ahead as high pressure gains the upper hand over our region. After some morning fog in the eastern zones, there is just a slight chance of some convective activity over the high country today thanks to a period of unstable NW flow. Otherwise, we will see fair skies and milder temps. More sun expected Wednesday as ridging increases. Temperatures will be well into the 60s with a few lower 70s likely. BT .LONG TERM...valid for Thu...Fri...Sat...Sun...Mon... Upper ridge dominates our weather Thursday into Saturday morning with dry and mild weather. High temperatures are expected to be in the upper 60s to lower 70s Thursday through Saturday. This upper ridge will be sliding eastward during this time so that it should be exiting MT Friday night. A weak shortwave is then progged to track northward Friday night, which could produce an isolated shower over the Bighorn Mountains. An upper low tracking eastward over the Pacific Northwest should bring scattered showers and thunderstorms to our southwest mountains Saturday morning, western areas Saturday afternoon, and to our whole CWA Saturday night. Showers are still possible during the day on Sunday with the upper low over central MT, which is a change from last night's model runs. A surface cold front should also move through the region Saturday night, bringing in cooler air for Sunday through early next week, with high temperatures generally in the 50s across the lower elevations. The air will be cool enough to change rain to accumulating snow in the mountains beginning Saturday night. Surface and mid-level pressure gradients behind the cold front appear favorable for breezy conditions for much of the area Saturday night through early next week. In addition, gap flow winds near Livingston are possible beginning Sunday afternoon and then continuing into early next week. For Monday, models diverge with the GFS moving the upper low more slowly and thus keeping showers possible and the ECMWF moving the low more quickly, giving a mostly dry day. Given the model uncertainty kept chance PoPs going on Monday. RMS && .AVIATION... Patchy fog is possible this morning over eastern MT and north central WY. A few showers are possible over the mountains this afternoon. Mountains will be obscured at times today. Otherwise, VFR will prevail. RMS && .PRELIMINARY POINT TEMP/POPS... Tdy Wed Thu Fri Sat Sun Mon ------------------------------------------------------- BIL 065 043/069 044/070 046/071 047/070 045/058 041/057 0/B 00/U 00/U 00/U 01/B 33/W 22/W LVM 062 037/067 036/068 038/071 043/066 039/053 037/052 1/B 10/U 00/U 00/U 02/T 42/W 23/W HDN 066 041/071 042/073 045/073 045/073 045/061 041/059 0/B 00/U 00/U 00/U 01/U 33/W 12/W MLS 065 042/071 045/073 046/073 049/073 048/061 042/058 0/F 00/U 00/U 00/U 11/U 33/W 12/W 4BQ 064 041/069 042/072 045/071 047/073 046/060 040/057 0/U 00/U 00/U 01/N 11/U 33/W 11/N BHK 062 040/070 043/071 045/071 047/073 046/062 041/058 1/B 00/U 00/U 00/N 11/U 32/W 11/N SHR 062 038/067 039/068 042/069 042/070 042/057 037/056 0/B 00/U 00/U 00/B 00/U 23/W 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None.