Area Forecast Discussion
Issued by NWS Billings, MT
Issued by NWS Billings, MT
521 FXUS65 KBYZ 200030 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 630 PM MDT Wed Jun 19 2024 .UPDATE... Satellite imagery shows broad troffing/cyclonic flow over the northern Rockies, but heights continue to slowly rise. Weak diurnal convection developed over our western mountains/foothills but this activity is already waning (though a cell just popped up recently near Red Lodge). The more interesting area is our southeast, where showers and some embedded thunder have developed from near Devils Tower to southern Powder River and Carter Counties. This is a region of low level jet forcing/moisture advection underneath RRQ of 90kt H3 jet lifting thru eastern MT. Instability is quite modest and thunderstorms will be weak, but places from Broadus to Baker eastward can expect scattered showers thru the remainder of the evening. Have raised evening pops a bit in this area. There could be a risk of fog in far southeast MT late tonight, especially w/ a little precip, but the HRRR suggests the better fog potential is closer to the Black Hills. With persistent SE winds this could lead to advection of low stratus (or fog) by late tonight...but this is of low confidence at this time. Otherwise, the remainder of the forecast area will be dry with low temps mostly in the 40s (milder than last night but still cooler than normal). JKL && .DISCUSSION... Rest of Today through Thursday Night... A longwave trough across the NW CONUS was evident on satellite imagery today with indication of a jet streak in the southwest flow over Wyoming. This was helping to produce some weak convection over the SE corner of Montana which was drifting northward. Isolated showers/thunder was also noted across central Montana clipping the Belts and Snowies. Most of this weak convective activity should die off after sunset, but we could have some showers linger in the far eastern zones thanks to a developing low level jet overnight. No significant impacts are expected. Lows overnight will be much milder than last night, with readings from near 40 west to upper 40s east. For Thursday...a bit more cloudy with an increasing chance of showers and thunderstorms in the afternoon and into the evening (15-40%). Better instability and shear may allow for a few stronger storms, though there is no severe risk at this time. This activity could linger through Thursday night thanks to available jet dynamics and WAA in mid level. High temperatures Thursday will range in the 70s to lower 80s, but increased dewpoints will make it feel notably more humid. BT Friday through Wednesday... Friday afternoon and evening have a decent probability of strong to severe storms as an upper trough moves into the region. Trough will push a cold front through the area late in the day into the evening. Low-level ESE flow from the Gulf of Mexico will push PWAT`s to 1-1.25 inches over the E half of the area. SREF showed MLCAPEs of 500-1000 J/kg with Bulk Effective Shear of 40-50 kt. NBM CWASPs were in the 60s. There is a 30-50% chance of showers with isolated thunderstorms in the morning, which could hinder strong thunderstorm chances later in the day. Will need to watch how this period unfolds with time. There is a 40-60% chance of showers and thunderstorms Fri. afternoon and evening. Highs on Fri. will be in the 70s to lower 80s. Dry weather will then move in through Sunday, as a strong ridge builds into the region. Temps will be in the 80s on Saturday, and in the 90s to around 100 degrees on Sunday. Probabilities were not very high for hitting 100 degrees. Billings had the highest chance at 11%. WSW flow will be over the region on Monday with a 20% chance of a shower or thunderstorm E of KBIL Mon. evening. Highs will reach the low 90s on Monday. Tuesday and Wednesday had more uncertainty in the Clusters, with solutions ranging from upper ridging to troughing. There will be low chances of precipitation on Wednesday. Highs were forecast in the 80s both days. Arthur && .AVIATION... VFR conditions will prevail through tonight with light and variable winds. Isolated showers/thunder is expected over the eastern half of the forecast area including the KSHR/KMLS/KBHK/K4BQ terminals. Local MVFR conditions can be expected with the thunderstorms. Weak convection may linger overnight south of KEKA and K4BQ. BT && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 047/078 056/080 058/084 060/097 062/091 058/087 059/085 00/U 24/T 41/U 00/U 11/U 11/U 12/T LVM 039/076 048/081 052/086 054/095 056/090 052/087 052/082 11/U 14/T 30/U 01/N 11/N 11/U 12/T HDN 045/081 056/083 056/086 057/099 060/093 057/089 057/086 01/B 36/T 51/U 00/U 11/U 10/U 21/U MLS 049/079 057/080 057/082 058/095 063/090 059/087 060/084 11/B 26/T 61/B 00/U 20/U 21/U 32/W 4BQ 048/079 057/079 058/084 059/097 064/092 060/089 061/085 31/B 36/T 51/U 00/U 10/U 20/U 21/U BHK 048/075 053/074 055/081 052/090 061/089 055/086 057/083 21/B 25/T 62/W 00/U 10/U 21/U 32/T SHR 044/079 051/081 053/084 056/096 061/093 056/088 056/086 11/B 46/T 41/U 00/U 10/U 10/U 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings