Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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343 FXUS63 KBIS 030626 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 126 AM CDT Mon Jun 3 2024 .KEY MESSAGES... - Chances for showers and thunderstorms continue through the first half of the week. Temperatures will be near to slightly above average, with highs in the lower 70s to lower 80s this week. - Strong northwest winds are possible Tuesday through Thursday. && .UPDATE... Issued at 122 AM CDT Mon Jun 3 2024 All storms and have died out and skies are clearing. With the high dewpoints we added patchy fog almost everywhere, especially in river valleys. UPDATE Issued at 1002 PM CDT Sun Jun 2 2024 Atmosphere has stabilized greatly over the past hour, and Mercer/Oliver County severe storm has diminished, with only small hail remaining a concern. Expect any lingering convection to diminish by late tonight, with quiet weather through the overnight. UPDATE Issued at 644 PM CDT Sun Jun 2 2024 Severe threat continues over the area, with the main focus currently on storms that are orientated more or less along a boundary stretching from near Jamestown east-southeastward towards Fort Yates. Storms have been slow to move in this area, and have been following similar paths, thus flood concerns continue. Strongest instability (~2000-3000 J/Kg) also remains in the vicinity of this boundary and southward. Another line of storms stretching from near Portal southward to just northeast of Dickinson also continues to move east. Southern portions of this line are tapped into elevated instability (1000-2000 J/Kg), so will have to continue to monitor this area. UPDATE Issued at 416 PM CDT Sun Jun 2 2024 Have issued a severe thunderstorm watch over our area for counties along and south of Highway 200, and east of Highway 85. Severe threat continues throughout the area. && .DISCUSSION... Issued at 116 PM CDT Sun Jun 2 2024 An active upper level flow will remain over the Northern Plains through mid-week. Strong to severe convection today associated with an upper level impulse congruent with a surface boundary developing over central ND early this afternoon and moving to the east. Latest surface analysis shows a possible weak circulation near Bismarck with a warm front extending east into the James River Valley. On and off convection has been occurring in this area of warm advection all morning long, with a few stronger cells from time to time. One severe thunderstorms warning was issued associated with this activity in the past 30 minutes. Additional convection is situated from southwest through north central ND. This convection has not been as strong as of yet, but does look to be intensifying a bit within the past hour. There looks to be a shortwave around northwest ND at this time from the WV imagery, which seems reasonable given the recent uptick in convection. A special 19Z sounding will be released to help determine the extent of the erosion of CIN over the south central. In general, it looks like the potential for convection will continue over central ND as the surface trough becomes more established within an area of increasing instability and diminishing CIN with strong bulk shear already situated over the area. Initially if discrete convection can sustain itself, large hail looks to be the initial threat. Of course a local strong gust also can`t be ruled out. We do think as we go through the afternoon, convection may develop into more of a linear form, with winds becoming the bigger threat. Whether or not this occurs by the time convection moves out of the forecast area, remains to be seen. After this wave moves through we get a brief break late tonight into Monday before another, stronger wave moves through the area. This wave will develop a closed upper level circulation over southern Canada with another strong impulse tracking eastward along the International Border through Montana and then lifting northeast into southeast Saskatchewan. At this time, the severe threat looks a bit limited, mainly due to the timing. The brunt of the forcing pushes through the local area late Monday night into early Tuesday, beyond the diurnal maxima for instability. However, think we could have a narrow window of opportunity for some strong to severe convection Monday evening. Currently SPC has the area within a general risk for thunderstorms. The CSU Machine learning probabilities does show a finger of higher probabilities extending from the eastern Dakotas, back into southwest ND. We`ll have to continue to monitor as we get closer. On Tuesday, the upper low tracks form southern Saskatchewan into southern Manitoba. We could be dealing with ongoing showers and thunderstorms from overnight Monday into Tuesday morning, but by Tuesday afternoon, the strongest forcing will have moved to our east. Most of the forecast area would be within an unfavorable location for shower/thunderstorm activity. The far north may be close enough to the low for some shower activity. Depending on the eventual timing of this system the James River Valley could also see some potential afternoon shower/thunderstorm activity should the system slow a little. Currently though, the higher probabilities for convection remain east of the forecast area Tuesday afternoon. As we move through mid-week the upper low lingers a bit over southern Canada, keeping the forecast area within a favorable area for strong west to northwest winds Wednesday and possibly again on Thursday over eastern portions of the forecast area. We could eventually need wind highlights, especially Wednesday. The ECMWF SA page has a pretty strong signal (and increasing) for winds and wind gusts Wednesday across most of the forecast area. Then a weaker signal for the far northwest/north central into the JRV on Thursday. The potential for showers and thunderstorms does diminish quite a bit beyond Tuesday with just some lingering showers north and east on Wednesday, then dry conditions Wednesday evening and through the remainder of the forecast period. Temperatures through the period remain in the seasonable range with highs mostly in the 70s but with a few 80s possible Monday, then some 60s possible Tuesday through Friday. Lows generally in the 40s and lower 50s through the period. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 122 AM CDT Mon Jun 3 2024 VFR tonight with patchy fog and light winds. CLouds will increase through the day, staying VFR. Another wave of thunderstorms will move west to east starting in the afternoon and ending overnight. Conditions could dip to MVFR in them with gusty winds. Otherwise winds will be southeast around 15kts. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Smith DISCUSSION...TWH AVIATION...Smith