Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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293 FXUS63 KBIS 010923 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 423 AM CDT Sat Jun 1 2024 .KEY MESSAGES... - Dry today, then chances for showers and thunderstorms tonight through the first half of next week. Near or slightly above average highs in the 70s and 80s through much of the work week. - Isolated to scattered severe storms will be possible Sunday, with hail up to golf ball size, 60 mph winds, and a tornado or two. && .DISCUSSION... Issued at 420 AM CDT Sat Jun 1 2024 Currently light showers are moving through the eastern half of the state, riding a surface trough and an upper level wave. The surface trough is in the Devil`s Lake Basin and the upper wave is in the north central. These showers should be east out of our area by sunrise as the subsistence on the backside of the wave moves over. With this, a mostly sunny day with highs in the 70s is forecast today. Flow aloft will be mostly zonal today with a warmer thermal ridge moving in ahead of a shortwave trough for Sunday. As the wave opens up over the state, a slight chance of showers and maybe thunderstorms are possible over the south central tonight. Isolated to Scattered Severe Storms Sunday: A quick moving northern Rockies wave will move through Sunday, with a surface low in southern South Dakota. This will also carry a very warm 850mb layer over. The wave will also have a lagging surface cold front moving west to east Sunday afternoon and evening. With around 35kts of shear and 1500-2300 J/kg of CAPE storms will likely first fire as scattered supercells before all the convection lines up on the cold front. The shear vector is parallel to the front, supporting a line of storms as the main storm mode. Another concern will be a tornado or two. Helicity values are well over 150 m2/s2, depicting the chance of a quick tornado along the line or right away when the isolated storms form. The CAMs have these isolated cells forming in the west late morning, then forming into a line in the afternoon closer to the Missouri River when more CAPE is available along the front. They should all move east and out by sunset. SPC has a marginal risk from around Highway 85 to the Missouri River about, and a slight from there east. For now we are messaging golf ball sized hail for the supercell potential early on, then 60 mph winds and a tornado or 2. After Sunday, the flow goes back southwest as another bigger trough forms in the Pacific Northwest. A very warm thermal ridge moves in Monday ahead of this. Highs Monday will be actually above average for once with highs in the upper 70s and lower 80s. Tuesday as the wave moves in, the chances of showers and thunderstorms increase. The backside of the wave will bring in cooler temperatures, back below average. A surface low with this will tighten the pressure gradient making the southwest breezy, but sub-advisory level Tuesday. The rest of the week we will be under a large omega looking ridge with another low forming in the ocean. Temperatures should be around average in the low to mid 70s with the southwest maybe around 80. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 420 AM CDT Sat Jun 1 2024 All VFR through the period. Winds will be shifting from the west to the south by Saturday evening. A few gust around 20kts are possible. Skies will be mostly clear after the rain moves through. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Smith AVIATION...Smith