Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
875 FXUS65 KBYZ 191520 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 920 AM MDT Thu Sep 19 2024 .UPDATE... Radar showed a few showers moving SE in a line from E Musselshell County to E Big Horn County at 15Z. In addition, web cam showed some lingering stratus/showers in Cooke City, and Bowman radar showed light showers lingering in Fallon County. Given cyclonic flow continuing thru the day and some signals from the CAMS, have updated PoPs to include 20 PoPs mainly over the NE half of the area through the afternoon. In addition, winds were gusty this morning, from the lower 30s W to lower 50s E. Soundings showed good mixing down of gusty winds thru much of the day, but diminished them in the late afternoon. Thus nudged gusts toward the NBM 90th percentile. Also updated sky cover based on latest satellite imagery. There was altocumulus over the central zones and stratus in Fallon County. Everything else was in good shape. Arthur && .DISCUSSION... Today through Friday... Satellite imagery shows slow-moving upper low moving to the northeast over southeast SK. We continue to see showers wrap southward on the back side of the low and into southeast MT. As of 08z, showers were located over and east of Rosebud County. This activity will continue to trend weaker and should diminish entirely by around daybreak. The remainder of the day will be dry with slowly rising heights in westerly flow aloft. There is a notable cut off low over central CA that will move thru the central and southern Rockies over the next few days, missing our region entirely as we will remain impacted by the drier zonal flow. W-NW winds will remain breezy today with highest gusts (30-40 mph) over our east. As the low departs and we see pressure falls to our west, winds will decrease over our west this afternoon, and the east in the early evening. Winds will then be much lighter regionwide tonight. A Pacific wave dropping out of southern BC will cause a brief period of pre-frontal warming and breezy/mixed west winds on Friday. A low risk (10-20%) of showers is expected by late afternoon as a cold front arrives and shifts winds to the north. The current nighttime period is remaining seasonably mild (mostly 50s) due to the wind and cloud cover. We should see temps climb to the low-mid 70s today, and after a chillier night with much less wind tonight, mid 70s to around 80F on Friday. JKL Friday night through Thursday... Zonal, westerly flow will persist Friday night through Monday. The latest ensemble runs generally depict this timeframe to be uneventful and dry. There is a time lag with the latest NBM run though, as previous deterministic models showed a band of moisture moving across the state early Monday. The latest deterministic models no longer show this, though the NBM still has a low chance (15-40% higher chance in the west) for precipitation for much of the forecast area. Despite the uncertainty among models, ensembles do depict a weak shortwave moving across the Northern Rockies, Monday. After this wave, ridging is depicted for much of next week, with normal to above normal temperatures and dry conditions. Highs will be in the 60s this Saturday, 60s to low 70s Sunday through Tuesday, next Wednesday and Thursday could see highs around 80F. Matos && .AVIATION... Isolated showers are expected today, mainly over southeast Montana, but conditions should remain VFR. W-NW winds will remain breezy for much of the day, gusting 20-35 knots (strongest east), before diminishing in the late afternoon and evening. Winds tonight will be much lighter. && .PRELIMINARY POINT TEMP/POPS... Tdy Fri Sat Sun Mon Tue Wed ------------------------------------------------------- BIL 074 050/077 045/062 040/070 050/069 047/074 048/078 1/U 01/U 20/U 00/U 13/W 10/U 00/U LVM 072 044/074 036/063 035/073 044/067 040/074 043/080 1/U 01/N 10/U 00/U 13/T 10/U 00/U HDN 075 045/078 043/063 037/072 045/070 043/073 045/080 2/W 01/U 30/U 00/U 12/W 10/U 00/U MLS 073 049/076 045/062 039/069 046/069 045/071 045/076 2/W 00/U 30/U 00/U 01/E 10/U 00/U 4BQ 073 046/079 045/062 038/070 046/067 045/070 044/077 2/W 00/U 20/B 00/U 01/E 10/U 00/U BHK 072 047/079 043/063 036/067 042/068 043/069 043/075 2/W 00/U 20/B 00/U 01/B 10/B 00/U SHR 076 042/081 042/063 034/072 041/070 040/072 040/081 1/U 00/U 21/B 00/U 03/W 21/U 00/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings