Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
441 FXUS65 KBYZ 150846 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 246 AM MDT Sun Sep 15 2024 .DISCUSSION... Today through Monday... Satellite imagery shows SW flow aloft ahead of deepening trof along the Pacific coast. There is a band of broken high clouds lifting thru the region, and as of 07Z there is a south to north clearing trend...which should continue as winds along keep backing. Dry conditions will persist for the remainder of the night. A surge of warmer air will yield highs in the 80s to near 90F today, warmest east of Billings, with a developing easterly wind. Mixing will be fairly deep and we should see the east winds gusting around 20 mph many areas by this afternoon. The moderate winds along w/ hot temps and RHs dropping to the teens will elevate fire concerns today. This evening, we anticipate a southeasterly low level jet (850mb winds of 30-40 knots) to develop over southeast MT. This will result in a mild night w/ poor RH recovery over eastern ridges, and any existing fires could remain active. This could include the Short Draw Fire in southern Powder River County. Something to watch. If this fire does become active today the E-SE winds would spread smoke to the WNW thru much of our forecast area. Increasing high-level moisture from the southwest may be enough to allow for isolated light/high-based showers to develop over the Beartooth-Absarokas during peak heating hours. Outside of this, today and tonight should remain dry. On Monday, as an upper low develops over the western great basin and southerly flow aloft trends toward diffluent, there is a greater chance (20-50%) of afternoon showers & thunderstorms over our west. Pwats are actually expected to rise to near 0.80" (1-2 standard deviations above normal for mid-September). Any storms would have the potential to produce erratic winds. There is some uncertainty whether or not a few thunderstorms develop over southeast MT on Monday (a few high-res models hint at this), but with drier air, higher heights and warmer mid levels (700mb temps to +12C) in our east will keep the forecast dry for now. High temps tomorrow will range from near 80F in the west to near 90F in the east. Min RHs on Monday will be mostly 20s to lower 30s. JKL Tuesday through Sunday... Into Tuesday, an upper level low is forecasted to move from Idaho to western MT. This system is still looking to favor areas west and northwest of Billings with beneficial rainfall. Here are the chances for at least half an inch of precip through Wednesday night at the following locations: Livingston (65%), Billings (40%), Miles City (25%) and Sheridan, WY (15%). An associated front coming up from the south is expected to move through late Tuesday, bringing a small chance of thunderstorms. Breezy conditions, mainly through SE MT, are also forecasted with the passage of the front. For Wednesday, widespread breezy west winds are expected across the region. As the low lifts north and east Thursday, ensembles keep troughing over the western US, continuing the cool and unsettled pattern. As for mountain snow, snow levels will drop to around 9-10,000 feet Tuesday night, giving the Beartooth pass up to a 30% chance of getting at least an inch of snow. High temperatures will be in the 70s west to 80s east Tuesday, 60s/low 70s Wednesday through Saturday and 60s Sunday. TS && .AVIATION... VFR will prevail over the next 24 hours, w/ periodic mid & high clouds. Isolated light showers are possible over the Beartooth- Absaroka Mountains in the late afternoon and early evening. Winds at the surface will shift to the east (gusts to 20 knots) today. This evening, a southeasterly low level jet and resulting LLWS will impact locations east of KBIL (i.e. KMLS & KBHK). JKL && .PRELIMINARY POINT TEMP/POPS... Tdy Mon Tue Wed Thu Fri Sat ------------------------------------------------------- BIL 084 053/081 055/078 052/071 050/069 048/070 047/068 0/U 01/B 46/W 63/W 23/W 33/W 33/W LVM 082 047/081 048/071 043/066 042/067 040/067 039/066 1/U 14/T 78/T 74/W 35/T 34/W 34/W HDN 088 051/084 052/082 050/073 049/071 046/070 044/068 0/U 00/B 34/W 63/W 22/W 33/W 33/W MLS 087 058/087 058/084 053/070 051/068 048/068 047/063 0/U 01/U 11/U 73/W 21/B 33/W 32/W 4BQ 088 056/090 057/088 053/074 051/071 048/068 045/064 0/U 00/U 11/U 62/W 12/W 33/W 33/W BHK 087 056/088 056/089 051/072 048/071 045/070 044/065 0/U 11/U 01/U 62/W 12/W 33/W 33/W SHR 089 049/087 049/082 044/075 044/068 042/068 042/067 0/U 00/B 22/W 41/B 23/W 34/W 33/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings