Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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105 FXUS63 KFGF 240640 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 140 AM CDT Mon Jun 24 2024 .KEY MESSAGES... - Showers and thunderstorms will move into eastern North Dakota, especially northeast parts, after midnight tonight. Isolated severe storms are possible. - Monday will see additional severe storm chances for all areas. - The next storm threat arrives in the Thursday to Friday time frame. && .UPDATE... Issued at 133 AM CDT Mon Jun 24 2024 Strong to severe storms entering northwest ND out of southeast SK will keep our attention in the near term. This is being driven by mid level impulse riding over shortwave ridging, with additional forcing from low level jet feeding 1000-2000 J/kg of instability and sufficient low level moisture amidst 50+ kt of shear. This environment will confidently sustain itself through sunrise supporting severe convection capable of large hail, and to a less confident degree, gusty winds to 70 mph. While this convection has been persistently tracking southeast at 40-50 mph, and in such a way that it would reach the Devils Lake basin around 09Z (4 AM CDT), there is questions on whether the warm sector holding aforementioned instability will advect with this convection. If the convection becomes detached from this instability, then convection will tend to lessen in intensity. Should this happen, the chance for severe hazards would be lowered. On the other hand, should instability pool advect with the the convection`s trajectory, the chance for severe hazards would be medium-high within the Devils Lake basin through at least 12Z (7AM CDT), potentially lasting into mid/late morning hours. This potential outcome also consists of additional updrafts developing behind ongoing storms, which may open up potential for multiple robust storms capable of severe hazards. Another potential outcome features robust convection tending more south-southeast movement, favoring a tracking that rides more along the leading edge of instability pool. This would bring medium-high chance of severe convection starting to enter into the southern Devils Lake basin / Sheyenne River Valley between 10Z-12Z (5AM-7AM CDT). Monitoring radar and satellite trends will reveal which scenario unfolds, particularly within the 08Z-09Z time period. UPDATE Issued at 1000 PM CDT Sun Jun 23 2024 Convection is now starting to form across northeastern Montana and northwest North Dakota this evening; however, most CAMs are not picking up on this development. Guidance is temporally displaced by at least a few hours in most cases, with the HRRR and NAMNest weakening convection as it approaches eastern North Dakota. Will continue to monitor the environmental conditions ahead of these storms as they approach the area. At this time, current guidance brings the first storms into the Devils Lake area by around 09Z, then into the Red River Valley by around 12Z. UPDATE Issued at 655 PM CDT Sun Jun 23 2024 The forecast remains on track this evening with temperatures in the low 70s along the International Border and low 80s in the southern Red River Valley. Isolated cumulus continues to diminish in coverage across northwest Minnesota with otherwise clear skies across the region. Watching for development of convection in western North Dakota in the coming hours in order to determine timing of any potential morning convection across eastern North Dakota. && .DISCUSSION... Issued at 233 PM CDT Sun Jun 23 2024 ...Synopsis... The first 700mb shortwave over the Minnesota arrowhead continues to push to the east. Haven`t seen any precipitation in this FA from the wave, but there has been fairly extensive cloud cover. Brief 500mb ridging follows this wave, although overall it looks much flatter and a little faster than it did several days ago. There may be some pieces of shortwave energy (and somewhat of a low level jet) that eject eastward behind this ridge after midnight and into Monday morning, which may bring scattered thunderstorms to portions of the Devils Lake region and eastern North Dakota. There may or may not be a break as this activity should weaken over this FA by mid to late morning, before additional storms fire up during the afternoon. The net result of the flatter/faster ridging is that the warmest 700mb temperatures on Monday are squashed a little further south and east. Even so, by 18z Monday to 00Z Tuesday, 700mb temperatures look to range from +9C along the Canadian border to +15C along the Dakotas border. Beyond this, the flow turns more northwest, with the next substantial wave sometime in the Thursday to Friday time period. ...After midnight tonight... The various CAM solutions seem to agree on scattered storms developing over southern Saskatchewan or western North Dakota after midnight tonight, with them moving into the Devils Lake region or portions of eastern North Dakota toward sunrise Monday morning. The Day 1 SPC Convective Outlook highlights a slight risk (level 2 of 5) for far northwest North Dakota, tapering to a marginal risk (level 1 of 5) for the Devils Lake region. The HREF shows the stronger UH tracks during this period extending from northwest North Dakota toward the western fringes of this FA and weakening toward morning. So will keep the idea of weakening storms and a good amount of cloud cover moving into at least areas north of the Interstate 94 corridor in North Dakota and the highway 10 corridor in Minnesota tonight. ...Monday... There is not a lot of confidence in what may happen on Monday, but to start with, what happens late tonight and lingers into Monday morning will have a big effect. Looking at the various CAMs, etc., feel there could be several different potential solutions. One, the convection moving into the Devils Lake region and portions of eastern North Dakota weakens and there is a break until more convection develops in the afternoon. Two, there is no break, and convection continues throughout the entire day across the entire FA (several CAMs show long duration UH track across the central and northern FA even during the late morning through the afternoon. Third, although most CAMs show a better chance for afternoon convection in the eastern FA, a few show some development back along the cold front, which may lag back in eastern North Dakota by 00z Tuesday (which could be part of the reason the slight risk area was expanded westward today). Fourth, the development which occurs back along the cold front quickly becomes severe and turns into a bowing MCS, producing damaging wind gusts as it progresses across west central Minnesota along the highway 10 corridor in late afternoon and early evening hours. Five, much of the capping holds, and only minimal convection occurs. Overall, there is a lot of uncertainty. ...Thursday to Friday... The general 500mb flow pattern should turn more to northwest flow aloft, with the next decent wave showing up somewhere in the Thursday to Friday time frame. Overall there is a lot of uncertainty on the timing and strength of the wave, so don`t want to put a lot of time into trying to determine what may occur. Stay tuned. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1145 PM CDT Sun Jun 23 2024 VFR conditions prevail at all sites through most of the period. Currently watching the progression of scattered showers and thunderstorms in northwest North Dakota tonight. These showers and thunderstorms are expected to move into eastern North Dakota during the late overnight period, impacting KDVL as early as 09Z, then moving off to the east through the remainder of the morning. Winds are expected to become southerly gradually through the overnight hours, with wind speeds in the 10 to 15 knot range by mid morning. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...CJ/Lynch DISCUSSION...Godon AVIATION...Lynch