Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
113 FXUS65 KBYZ 261956 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 156 PM MDT Wed Jun 26 2024 .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. With that said, isolated to scattered showers and thunderstorms will move into southwestern areas (including KLVM) after 20Z today. This activity will decrease in extent as it moves east through KBIL this evening. Local MVFR conditions with gusty winds and small hail are possible with any thunderstorm that develops today. 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. Uncertainties: KMLS could see a light shower this evening and KSHR could see a vicinity thunderstorm over the mountains this afternoon and evening. However, confidence is not high enough at this time to introduce this into their respective TAFs. Will amend as necessary. && .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 24/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 47/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 24/T 32/W 00/U 01/U 55/T 21/U 11/U MLS 065/093 057/074 050/073 055/091 061/082 057/079 054/084 25/T 31/N 10/B 01/U 63/T 22/T 11/U 4BQ 065/095 056/078 049/076 056/096 061/082 055/081 054/085 25/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 27/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 23/T 21/U 00/U 01/U 35/T 21/U 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings