Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
435 FXUS65 KBYZ 261951 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 151 PM MDT Sun May 26 2024 .DISCUSSION... Today through Tuesday night... A 500 mb shortwave trough is moving southeastward over central and eastern MT this afternoon. The wave is bringing increased winds aloft to the area. Surface heating is facilitating steep low- level lapse rates that are allowing the winds to mix down to the surface. Strongest wind gusts to 35-45 mph this afternoon-early evening will be in our western foothill locations from Livingston to Big Timber northward to Harlowton. For much of the rest of the area, expect wind gusts in the 20-35 mph range. As the wave passes the area, there is a 20-40% chance of showers south of Big Timber-Billings-Miles City. Drier air is moving in with this wave so showers will not be able to drop as much rainfall as they did yesterday or early this morning. The wave will exit MT to the east late this evening. In its wake, any showers and gusty winds will diminish over our area. A 500 mb ridge will then dominate our weather overnight into Tuesday night with mainly dry conditions. Warmer air moving in aloft will contribute to warmer temperatures on Monday and then a change to low-level southeasterly winds will cause further warming on Tuesday. By Tuesday night, the 500 mb ridge will have moved far enough eastward that areas west of Billings will be under cyclonic southwesterly flow that will produce a few isolated-scattered showers and thunderstorms (20-30% chance) in the western mountains and adjacent foothills. Low temperatures will generally be in the 30s and 40s tonight then 40s Monday night and 50s Tuesday night. High temperatures will mainly be in the 60s and 70s Monday and 70s to lower 80s Tuesday. RMS Wednesday through Sunday... Wednesday will see ridging in the area with high 70s and low 80s across the region. Locations were there is snowmelt concerns will see tempeatures generally in the 60s with lows Wednesday morning being in the 40s. These locations are currently above normal in SWE due to recent late season snowfalls. NOHRSC average modeled snowpack temperature is showing temperatures near 32F for all but the highest peaks indicating the snowpack is ripe for melting. This could lead to a quick snowmelt being exacerbated by 0-10cm soil moistures above 80th percentiles and even 90th percentiles in some regions. However, current hydrographs show streams and rivers that have handled recent heavy snowfall and precipitation without much issue. The warmup with above normal temperatures also looks to be brief as a system comes through late Wednesday/early Thursday lowering temperatures. Taking all of this into consideration, it is likely that streams and rivers near the foothills will see rises but major flooding is not expected though much uncertainty remains. Streams will see the quickest response with peak river levels usually occuring a couple days after peak heating. Individuals along waterways should be prepared for high water levels. Looking at the WPC Clusters, there is a lot of uncertainty in how the troughs for next week will evolve with disagreement in whether they will be slower moving and deeper or more progressive. It is difficult to discern between the two waves on the clusters but generally the stronger and deeper the troughing the more rainfall we can expect. Overall, Wednesday morning through Friday morning most of the region will see a 40-70% chance for >0.25 inches of precipitation. Wednesday will see some ingredients necessary for severe weather. GFS soundings are currently showing CAPE values in excess of 1,500J/kg and 0-6km shear over 50kts. This combined with an upper level trough and PWAT values of 0.8-1.0 will bring the potential for some severe thunderstorms. Rainfall for Wednesday through Thursday is not expected to have much impact on flooding if current precipitation totals continue. Thursday we will be under upper troughing, although temperatures will be near normal. Saturday will see a downsloping pattern return with temperatures in the 70s. Sunday will see temperatures warm even more with mid 70s to low 80s across the region. Torgerson && .AVIATION... Most of the region will continue to see winds gusting into the 20s and 30s with some 40s for locations in western gap areas until around 03Z Monday. Midlevel cloud will persist today through this evening before we get clearing Monday. Torgerson && .PRELIMINARY POINT TEMP/POPS... Mon Tue Wed Thu Fri Sat Sun ----------------------------------------------------------- BIL 044/072 047/080 053/079 048/064 043/068 046/073 048/079 00/U 00/U 06/T 74/W 23/T 11/U 11/B LVM 038/071 043/079 050/075 041/059 037/065 040/072 044/077 00/U 01/U 29/T 75/T 23/T 11/U 11/B HDN 041/072 043/081 052/081 048/066 041/069 043/074 048/081 10/U 00/U 04/T 74/W 32/W 11/U 11/B MLS 046/071 044/078 055/084 050/067 043/069 046/074 048/079 10/U 00/U 02/T 62/W 32/W 11/U 10/B 4BQ 046/069 045/079 055/086 050/067 043/069 046/072 048/080 10/U 00/U 02/T 52/W 32/W 11/U 11/U BHK 042/069 042/075 049/080 049/067 041/068 043/072 045/077 11/U 00/U 02/T 62/W 32/W 11/U 11/U SHR 040/069 043/079 051/083 046/064 038/067 041/072 046/079 20/U 00/U 03/T 64/T 33/T 21/U 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings