Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
182 FXUS65 KBYZ 210055 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 655 PM MDT Thu Jun 20 2024 .UPDATE... Mostly quiet weather around the forecast area this evening. There is an area to watch across our north, east of Snowies, thru the evening. A couple stronger storms developed along the northern Musselshell and northern Custer county lines over the past few hours. Brunt of activity has stayed to our north but as ESE low level jet increases toward sunset would not be surprised to see a strong to severe storm develop across our northeast (potentially impacting Forsyth-Miles City-Baker between roughly 02-07z)... though it should be noted that high res models keep convection to our north. Otherwise, chance of showers and embedded thunderstorms will increase from the south overnight as a shortwave emerges from the southwest flow aloft. Low level easterly winds will persist, and there will be sufficient elevated instability for thunderstorm potential along w/ small hail and pockets of heavy rain during the overnight hours and early Friday. This includes the Billings metro area. Finally, area of stratus over Carter County is slowly advecting to the east/north. This will likely evolve into a stratus/fog combo as the night wears on. In fact, HRRR suggests 925mb moistening along our western foothills (per upsloping) by daybreak tomorrow. Something to watch. Overall the next 12-18 hours are messy, and the showers/stratus/fog will all have impacts on Friday`s convection. Stay tuned. JKL && .DISCUSSION... Tonight through Friday night... Shortwaves and jet energy will move through WSW flow aloft tonight. With low-level ESE flow, PWAT`s will climb to 1 inch from KBIL S and E. Some areas showed MUCAPE of 500-1000 J/kg (elevated) and bulk effective shear around 40 kt tonight. So with enough lift there could be a few strong storms, mainly along the northern tier, N of KBIL, where HREF showed a few updraft helicity tracks. Had 20-30% PoPs much of the night over portions of the area based on CAMS. Had higher PoPs E of KBIL late at night as second wave moves through the area. HRRR showed fog, possibly dense, over Carter and Fallon Counties overnight. Satellite and web cams had low clouds moving into SE MT. Added areas of fog to the far E overnight, with patchy fog elsewhere N and E of KBIL. Next shifts can keep an eye out for possible dense fog advisory. It will be a warm and humid night with lows well into the 50s. Stronger trough moves across the area Friday through Friday night. HREF showed a few helicity tracks S and SE of KBIL Fri. morning. Helicity tracks become strong in the afternoon with an area of tracks N of the forecast area and a second area over Sheridan County and far SE MT. Northern area of tracks weakens as it moves SE into the forecast area in the evening. MUCAPEs Fri. afternoon and evening will be 1000-2000 J/kg and bulk effective shear will be 30 to 50 kt with the strongest parameters from KBIL E and S. Due to continued ESE flow, some areas showed an inversion on GFS soundings...so this inversion along with cloud cover could inhibit strength of some of the storms. High PWAT`s continue which will bring heavy rainfall with the storms. So, hail, wind and heavy rainfall will be the threats with any strong to severe storms. Highest PoPs (50-60%) will be E of KBIL in the morning. 30-50% PoPs in the early afternoon will increase late in the afternoon and continue into the evening. PoPs will quickly decrease W to E late Fri. night. Temps will be in the 70s to low 80s on Friday and in the 50s Fri. night. Arthur Saturday through Wednesday... Upper level ridging will continue to build into the Northern Rockies through the extended forecast period. Increasing heights will result in above normal temperatures and mostly dry conditions. The warmest day in the extended forecast will be Sunday with highs in the mid 90s, approaching 100F. The probability of a high temperature of 100F or greater is 20-60% from Columbus to Busby and Miles City. There is a low chance (10-25%) for showers and thunderstorms Sunday night as the ridging is briefly flattened by a weak shortwave. High temperatures for the rest of the week will be in the mid-upper 80s to mid 90s. Rivers and streams have fallen considerably over the past week but still have a bit to go to get down to normal summer flows. If you head out to the rivers to cool down this weekend be sure to wear life- vests and continue to use extra caution, especially with children. Matos && .AVIATION... Stratus is expected to edge into the area late tonight in Friday morning with conditions lowering to MFVR. Chances for showers and thunderstorms increase late tonight, to around 40 percent, over much of the area E of KLVM and continue through Friday morning with MVFR/IFR or lower conditions possible in the thunderstorms. Continued VCSH at KBIL, KSHR and KMLS TAFs for late tonight, mainly after 06Z. There is a medium chance of seeing a thunderstorm around KBIL and KMLS in the 12Z to 15Z timeframe as a 500 mb jet pushes into the area. Isolated to scattered showers and thunderstorms are possible again Friday afternoon but confidence is lower during this timeframe with the forecast depending on how the showers and thunderstorms evolve late tonight into Friday morning. Wetenkamp && .PRELIMINARY POINT TEMP/POPS... Fri Sat Sun Mon Tue Wed Thu ----------------------------------------------------------- BIL 057/079 056/084 059/097 062/091 058/088 058/090 061/093 24/T 31/U 00/U 11/U 10/U 11/U 12/T LVM 049/080 050/086 054/095 056/090 052/087 053/090 056/089 14/T 21/U 01/N 11/N 11/U 11/U 13/T HDN 056/081 054/085 057/099 060/092 056/090 057/092 060/096 55/T 41/U 00/U 21/U 10/U 11/U 11/U MLS 057/078 057/082 058/096 064/089 058/087 058/090 063/093 36/T 51/U 00/U 20/U 10/U 11/U 21/U 4BQ 058/079 057/084 058/097 066/091 059/088 060/091 063/094 46/T 41/U 00/U 10/U 10/U 11/U 11/U BHK 054/075 054/080 054/092 061/088 055/085 055/086 057/089 26/T 51/B 00/U 10/U 11/U 11/U 12/T SHR 052/080 051/083 055/097 061/092 055/087 056/091 059/093 37/T 31/U 00/U 10/U 10/U 11/U 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings