Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
493 FXUS65 KBYZ 310303 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 903 PM MDT Thu May 30 2024 .UPDATE... Updated forecast for latest model trends, and diminishing afternoon convection/wind gusts. Winds have been gusty today with a few areas pushing over 50 mph. Models in good agreement with wind gusts quickly diminishing with sunset, along with dying convection. There is a jet impulse and upper trof moving in from the west this evening. Jet induced Baroclinic Leaf is apparent over eastern Idaho into SW Montana this evening. This feature will spread eastward across the southern half of the forecast area tonight into tomorrow bringing a 20 percent chance for light showers overnight generally along and south of I-90/US-212. Light snow accumulations (up to 2 inches) are possible in the Beartooth/Absaroka and Bighorn mountains from this impulse crossing those areas tonight as well. Increasing cloud cover should hold overnight lows mainly in the 40s tonight, but a few areas could drop into the 30s for a chance for frost. Western valley locations have the best chance for a frost (Livingston). Chambers && .DISCUSSION... Rest of today through Saturday night... Satellite Imagery showed cyclonic flow over our region thanks to an upper low over Saskatchewan. The 300mb Jet was stretched from the Idaho panhandle into southern Montana. These features were producing scattered light showers over northern Montana with isolated activity across our CWA along with very brisk winds over our western zones (gusts 35-45 mph). Most of the shower activity will continue through the rest of the afternoon into the very early evening before dying off near sunset. A few sprinkles or showers may linger over the mountains overnight...extending east across the southern portion of our CWA late. Winds should also die down this evening. Overnight lows will range from mid 30s to lower 40s. For Friday...models indicate short wave energy tracking through the bottom of the trough. Again models hint at some weak ascent and scattered band of showers from Big Horn County eastward in the morning. As wave exits east it helps pull the larger trough east as well with some departing ascent over our east Friday afternoon producing some showers and perhaps an isolated thunderstorm. Winds will not be quite as strong in our western foothills tomorrow, but still on the breezy side (15-30 mph). Highs Friday will generally be 65-70 degrees. Showers end by Friday evening as the trough shifts east. Lows Friday night will be in the lower 40s. Saturday will start out with short term ridging over our area with mostly sunny skies. A low amplitude trough works into the Rockies by evening ejecting some energy eastward. So we are anticipating increasing clouds late Saturday with isolated to scattered showers/thunderstorms spreading west to east over the area Saturday evening and through the night. Best chance of measurable precipitation is across our NW zones (Wheatland, Musselshell). Any thunderstorms should be garden variety as GFS indicates the probability of CAPE over 500 J/kg is only 30-40% over south central sections in the evening. Look for highs on Saturday in the mid 70s to around 80 degrees. BT Sunday through Thursday... Clusters showed zonal flow over the area on Sunday, while deterministic models moved a trough through the region and had a cold front exiting the area. Scattered showers and thunderstorms were forecast for Sunday with the highest PoPs (40-60%) from KBIL W. Temps will be near normal. A ridge will move through the area Monday with SW flow moving in late. PoPs will increase to 60% over most of the area Mon. evening, with PWAT`s increasing late on Monday. CWASP had some values in the 50s, suggesting the possibility of some strong storms. PWAT`s will support possible heavy rain with thunderstorms. There was a 10-20% chance of at least 0.25 inches of precipitation Mon. night. Monday will be warmer with highs in the mid 70s W to mid 80s E. Clusters had either SW flow or the next trough over the area for Tuesday, and NBM had a 20-30% chance of showers and thunderstorms. It will also be cooler on Tuesday with highs in the mid 60s to mid 70s. Models had pattern disagreement for Wednesday with an upper ridge for Thursday. Forecast is dry with highs in the 80s. Arthur && .AVIATION... Today`s isolated showers and gusty westerly winds will continue to decrease this evening. Overnight, there is a low chance (15-30%) of additional light rain/snow showers developing over the Beartooth/Absaroka Mountains before moving east over the lower elevations south of KBIL early Friday morning. Then, there will be a 20-30% chance of showers with isolated thunderstorms from KMLS east and south after 18Z Friday. Localized mountain obscurations are possible in showers through Friday. Arthur/Arends && .PRELIMINARY POINT TEMP/POPS... Fri Sat Sun Mon Tue Wed Thu ----------------------------------------------------------- BIL 043/069 044/078 054/073 053/079 052/073 051/083 054/084 00/U 00/U 24/T 02/T 52/W 00/U 00/U LVM 036/068 040/077 049/072 050/075 046/070 048/080 051/084 00/U 00/U 35/T 05/T 61/N 00/N 00/U HDN 041/070 041/079 051/074 051/082 051/074 049/084 052/085 11/B 00/U 23/W 01/B 62/W 00/U 00/U MLS 041/068 043/078 052/075 051/082 053/073 050/082 053/083 02/W 00/U 22/W 01/B 62/W 10/U 00/U 4BQ 042/066 043/079 051/073 051/085 054/071 051/080 054/084 02/W 00/U 12/W 01/B 42/T 10/U 00/U BHK 038/067 041/077 050/075 048/081 051/070 047/077 050/079 02/T 00/U 24/T 11/B 52/T 10/N 00/U SHR 038/067 041/078 048/072 048/083 048/071 047/082 051/084 01/U 00/U 13/T 01/B 52/W 10/U 00/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings