Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
599 FXUS65 KBYZ 090321 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 921 PM MDT Wed May 8 2024 .UPDATE... Moderate to heavy rain showers were occurring from Rosebud County west, while scattered showers were occurring east of this area. Heavy snow continued in the mountains. Best precipitation was occurring in a surface convergence area with strong 850 mb frontogenesis. In addition, energy was wrapping around upper low that was centered over SD/NE. PWAT`s were above normal, ranging from .5-.6 inches, providing ample moisture for precipitation. Small temp/dewpoint spreads supported areas of fog from Rosebud County W and fog was seen on the web cams. Added areas of fog through the night, with patchy fog over far eastern counties. Besides the fog, also updated to lower mins a few degrees as some areas had already reached their low temperature forecast. Winter Storm Warnings in the mountains were in good shape through 18Z Thursday as precipitation will lighten up late tonight. Snow levels will remain above 6000` through the night, which will preclude any low elevation snow. Arthur && .DISCUSSION... Rest of Today through Thursday Night... Moisture. Is. Everywhere. While the upper low supplying all the weather we`ve seen the past few days is now located in western South Dakota and slowly progged to move east over the next day, wrapping around it is still an abundance of moisture flowing in to southern and central Montana. Upslope into the foothills and mountains is deep as well, and with a lot of moisture still available upstream, the current rain over the lower elevations and snow in the higher foothills and mountains will persist through tonight at it`s current rate. The Livingston area (not including Bozeman Pass) will see their snow slowly switch to rain this afternoon and evening, then likely seeing low clouds and fog roll in overnight through tomorrow morning, reducing visibilities along I-90. Across the lower elevations, rain will persist through the afternoon with the aforementioned moisture upstream continuing to move south into southern MT with it`s upslope flow. While rain should slowly diminish tonight, a persistent upslope through Thursday could keep light to moderate rain continuing along the foothills south of Billings. Despite all of the rain over the past couple days and today, streams are expected to remain below any potential flood stages. Only streams that may get close and have some minor flooding of low-lying areas will be focused in the area between Billings, Sheridan, WY, and Miles City, as those areas have reported 3-4" of rain so far over the past 72 hours. While those are very high amounts, the fact that the soil out there was very dry and had room to soak up a lot of water, and that it fell over a 2-3 day period assisted in preventing any major flooding concerns. On Thursday, one last, small push of moisture and rain showers will occur across the area, but accumulation potential from this will be much lower than yesterday or today, and little impacts are expected from it. By the evening, winds will become westerly and officially shut off the moisture from the area, ending this weather system impacting us once and for all. Vertz Friday through Wednesday... Building ridge aloft will bring dry and warmer weather Friday thru the weekend. We should see temps in the 60s Friday then 70s Saturday and Sunday. By Sunday afternoon the ridge will flatten enough such that weak energy emerging from southwest Canada may induce a few diurnal showers. Above normal temps (70s to near 80F) will continue Monday, but with an increasing chance of showers & t-storms in response to lowering heights and a stronger shortwave emerging from the developing WNW flow aloft. This energy will be associated with a surface cold front, so there is potential for gusty winds by late in the day as well. Tuesday & Wednesday look more active and cooler as a couple of additional waves drop thru an amplifying NW flow aloft. There is a good chance (30-50%) of showers on each of these days, and freezing levels will fall enough to produce some accumulating snowfall over the mountains, above 7kft or so. One final note. The upcoming warmer temps will melt much of the wet snow that is currently falling at elevations between 6000-8000 feet. Do not see a flood risk, but rivers/streams emerging from the foothills will likely see some rises this weekend. Any higher elevation snow melt will end by Tuesday when cooler temps arrive. JKL && .AVIATION... A slow-moving storm system will continue to bring frequent showers (especially west of KMLS & K00F) thru tonight and much of Thursday. MVFR to IFR can be expected, with poorest flying weather (possibly to LIFR in fog) along the foothills tonight into early tomorrow. Mountains will remain obscured in snow, especially the N-NE facing slopes. Brisk NW-NE winds (gusts 25-35kts from KBIL eastward) will decrease tonight and be lighter Thursday. JKL && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 041/058 041/066 043/076 047/078 050/078 050/072 046/065 87/W 30/U 00/U 01/U 22/T 35/T 33/T LVM 035/054 036/063 037/073 043/078 046/077 045/068 042/064 +7/W 20/U 00/U 01/U 22/W 24/T 33/T HDN 039/061 041/067 039/077 045/079 047/080 048/073 045/065 87/W 30/U 00/U 01/U 22/T 44/T 33/T MLS 038/063 041/067 042/075 048/077 050/079 049/071 045/064 34/W 10/U 00/U 01/U 12/W 33/T 22/T 4BQ 037/060 043/066 041/074 046/076 049/078 049/071 045/062 24/W 20/U 00/U 01/U 12/T 34/T 23/T BHK 035/064 039/067 041/075 045/075 047/079 047/069 040/063 23/W 10/U 00/U 01/U 12/T 33/T 22/T SHR 034/056 038/064 037/074 043/076 045/078 045/070 041/061 85/W 31/B 00/U 12/W 23/T 45/T 44/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning remains in effect until noon MDT Thursday FOR ZONES 67-68-171. WY...Winter Storm Warning remains in effect until noon MDT Thursday FOR ZONE 198. && $$ weather.gov/billings