Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
806 FXUS65 KBYZ 270315 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 915 PM MDT Wed Jun 26 2024 .UPDATE... A minor update to the going forecast this evening, mainly to capture the latest model trends. Hi-res models continue to show a couple of waves of shower/thunderstorm activity moving in from the west and just making it over the divide into western zones overnight. This activity generally dissipates before getting east of a Columbus/Ryegate line. Main impact with any thunderstorms overnight will be wind gusts to 40 mph and light rain. Another area to watch overnight is over far SE Montana where coverage and potential for storms is low, but if something does get going it could be a bit stronger than what is expected further west, due to interaction with the low level jet providing moisture advection and shear. Rest of the forecast is in good shape. Expect an early start to convection tomorrow (a few storms may be ongoing from overnight activity) with the potential for strong to severe storms ramping up by late morning, and continuing into the early evening hours. If you have outdoor plans tomorrow be sure to have a plan to get to shelter if a storm approaches. Chambers && .DISCUSSION... Through Thursday night... Weak shortwaves will move through the upper ridge through tonight. Scattered late afternoon thunderstorms will initiate over and near the western mountains. There is also a low probability (20%) that a few storms will move onto the plains through KBIL and KSHR. This trend will continue into the evening with 20% chances of showers and thunderstorms pushing further E into Fallon and Carter Counties. A few showers and thunderstorms will linger over the area overnight. Bulk Effective Shear will be 40-50 kt over SE MT this evening and MUCAPEs will be around 500 J/kg over the far W and SE. PWAT`s increase to around an inch this evening central and E due to low-level SE flow. Thus a few storms may be strong with heavy rainfall. SW flow ahead of an upper low skirting the NW U.S./SW Canadian border, will move quickly over the area on Thursday. The low will push a cold front through almost the entire forecast area by 00Z Friday. Thunderstorms should develop in the 16-18Z timeframe over KLVM, K3HT and near KBIL. HREF had storms a bit later around KSHR, then had storms moving E of Rosebud County after 21Z. The pattern was favorable for severe storms, especially strong winds and large hail...mainly from KBIL N and E. A strong 500 mb jet will move E into the western part of the area through 18Z, before the jet splits. Per the SREF, the highest probability of MUCAPE of at least 1000 J/kg was E of KBIL. That being said, GFS soundings had over 1000 J/kg at KBIL at 18Z. Bulk Effective Shear will be 40-50 kt over the entire area. Per the HREF, the highest 0-1 km SRH was E of the forecast area. Strong updraft helicity tracks were over the Musselshell River Valley beginning at 19Z and lasting through 00Z Fri., while other weaker tracks develop E of Yellowstone County after 21Z. All tracks weaken and move E of the forecast area after 02Z. PWAT`s climb to over an inch in the E in the afternoon due to southeasterly flow ahead of a surface low. So storms in this area could produce heavy rainfall. PoPs quickly fill in from W to E through KBIL through 18z Thursday with the highest PoPs (60%) over the W and NW zones. PoPs will continue spreading E through the afternoon, with 50-80% PoPs along the Musselshell River Valley. 50-70% PoPs will be E of KBIL after 21Z. Precipitation chances decrease to scattered in the evening with the highest PoPs over Fallon and Carter Counties. A few showers or storms will linger overnight. Main severe threats are strong gusty winds and large hail. A tornado cannot be ruled out over SE MT. Heavy rain will likely accompany the storms. Temps on Thursday will be in the low to mid 90s from KBIL and KSHR E, and in the 80s W. It will become windy behind the cold front with gusts in the 30s Thu. afternoon. Arthur Friday through Wednesday... Friday will be cooler than Thursday with widespread breezy conditions. Expect high temperatures to remain in the 70s across much of the area with 25 to 45 mph mph northwesterly wind gusts common. Low chances of precipitation exist during the afternoon as well under continued cyclonic flow (10-40% chance, highest north of Billings and over the mountains and immediate foothills). Ridging builds in for the start of the weekend allowing warmer and dry conditions to return. High temperatures look to be in the 70s to near 80 degF Saturday and 80s to 90s Sunday. By Sunday afternoon and evening, chances of precipitation increase again as another trough approaches the area (30-80% chance). With warm temperatures and a good moisture fetch from the Gulf of Mexico Sunday, the atmosphere should destabilize quickly. This, along with decent deep layer shear, may allow for stronger thunderstorms to develop Sunday afternoon and evening once again. Cyclonic flow will continue into Monday and Tuesday next week keeping low to moderate chances of precipitation across the region. Uncertainty remains in the upper level pattern Tuesday into Wednesday, but near seasonal weather looks to prevail. Arends && .AVIATION... In general, VFR will prevail through the period. There could be some (20%) isolated showers and thunderstorms in the western areas (KLVM) during the overnight. Expect showers and stronger thunderstorms to develop once again in the west around 18Z Thursday, moving east through the afternoon and early evening. The stronger storms could produce damaging winds and large hail on Thursday, with the best chance to see this activity residing around and east of K3HT to KBIL. Tomorrow will be breezy across the region with most locations seeing gusts of 20-30kts. Arends/Torgerson && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 063/090 053/074 048/077 052/089 058/080 055/080 054/084 16/T 31/N 00/U 01/U 55/T 12/T 11/U LVM 057/082 043/071 042/078 049/087 051/074 047/077 047/082 38/T 21/N 00/U 03/T 76/T 22/T 11/U HDN 060/092 052/076 046/079 052/094 057/082 052/081 051/086 16/T 32/W 00/U 01/U 55/T 21/U 11/U MLS 064/093 057/074 050/073 055/091 061/082 057/079 054/084 15/T 31/N 10/B 01/U 63/T 22/T 11/U 4BQ 064/095 056/078 049/076 056/096 061/082 055/081 054/085 14/T 31/U 00/U 01/U 33/T 11/U 11/U BHK 061/091 055/075 046/070 050/084 058/082 055/079 052/083 26/T 51/N 10/B 11/N 53/T 22/T 11/U SHR 060/092 050/075 044/079 052/096 056/078 050/080 049/084 14/T 21/U 00/U 01/U 35/T 21/U 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings