Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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344 FXUS63 KBIS 011746 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1246 PM CDT Sat Jun 1 2024 .KEY MESSAGES... - Dry today, then chances for showers and thunderstorms begin tonight and continue through the first half of next week. Temperatures will be near to slightly above average, with highs in the 70s to lower 80s through much of the work week. - Scattered severe storms will be possible Sunday afternoon and evening. Threats include large hail up to the size of golf balls, damaging winds up to 60 mph, and a tornado or two possible. && .UPDATE... Issued at 1246 PM CDT Sat Jun 1 2024 Daytime satellite imagery shows some fair weather cu have formed along the International Border in far northern North Dakota, otherwise it`s sunny skies across the rest of the area. Still seeing a breeze across the far north as well, but otherwise it`s a pleasant first day of meteorological summer. No changes needed with this update. UPDATE Issued at 919 AM CDT Sat Jun 1 2024 Broad surface high pressure extends from eastern Montana into southwest South Dakota, with not a single cloud in the sky this morning across western and central North Dakota. There is a slight breeze already across northern North Dakota due to a marginal surface pressure gradient, but the remainder of the area should have overall light winds today. Expect highs in the 70s and mostly sunny skies, with cloud cover beginning to increase this afternoon across western North Dakota. No changes needed with this update. UPDATE Issued at 629 AM CDT Sat Jun 1 2024 The upper level wave axis and surface trough axis have passed, and so have the showers. The rest of the day will now be mostly sunny under slightly high pressure and northwest flow. && .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 /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1246 PM CDT Sat Jun 1 2024 VFR conditions through the period with mostly sunny skies this afternoon and evening. Breezy southwest winds across northern terminals will diminish after sunset tonight. Chances for rain begin increasing overnight tonight and become more widespread through the day Sunday, especially across western and northern North Dakota. Included VCTS at KDIK/KMOT late in the period, and VCSH at KXWA. Any heavier showers or thunderstorms could produce MVFR conditions but too low of confidence to get more specific on timing with this update. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Jones DISCUSSION...Smith AVIATION...Jones