Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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235 FXUS63 KFGF 312022 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 322 PM CDT Fri May 31 2024 .KEY MESSAGES... - Isolated to scattered severe thunderstorms are possible Sunday afternoon and evening. Risks could include hail larger than 1 inch, winds greater than 60 mph, and possibly a few tornadoes. - Additional chances for showers and thunderstorms are in the forecast for Tuesday evening and overnight. There is a low chance for isolated strong thunderstorms. && .DISCUSSION... Issued at 322 PM CDT Fri May 31 2024 ...Synopsis... A weak shortwave continues to traverse the Northern Plains today, bringing only a slight chance for showers and isolated thunderstorms to areas north of Highway 2. There are minimal chances for severe thunderstorms today and the most likely scenario supports mainly embedded thunderstorms; however, a stronger storm or two cannot be ruled out along the International Border, with small hail and gusty winds possible this evening. This would be associated with a rather narrow window where MUCAPE increases to around 1000 J/Kg in the presence 0-6km shear upwards of 45 knots. A much stronger H5 trough is set to impact the area on Sunday, bringing a much better chance for strong to severe thunderstorms. This will be the next of several shortwaves and troughs rotating around a large upper low that continues to slowly move eastward across central Canada. There will be another trough passage heading into Tuesday afternoon and evening, which could bring another chance to see showers and thunderstorms. ...Severe Thunderstorms Possible Sunday... Isolated to Scattered severe thunderstorms are possible on Sunday, with hazards that could include hail of 1 inch or greater, wind gusts of 60mph or higher, and possibly a few tornadoes. Storm mode at this point retains some uncertainty, with a strong dependency on where initiation occurs. This depends on the forward progression of the trough axis providing our lift. SBCAPE is expected to increase ahead of this trough, with a 70 percent chance of 2000 J/Kg or greater (southern Red River Valley) and an 80-90 percent chance of 1000 J/Kg or greater (central and southern Red River Valley). Soundings are consistently showing good wind shear at all levels, with low level shear in the range of 20 to 30 knots and deep layer shear upwards of 40 knots. Storms are likely to start as discrete supercells that will quickly become clusters and eventually linear. In the event of early initiation further west, we would likely see mainly cluster and/or linear mode for much of the CWA; however, if initiation occurs later, discrete supercells would impact portions of eastern North Dakota and bring higher impacts to include golf ball sized hail, wind gusts of 70mph or higher, and tornadoes. ...Active Weather Continues... Another, somewhat strong, trough approaches the area late Monday night into Tuesday. Some ensemble members are developing a negative tilt as this trough moves into western Minnesota; however the majority of solutions are showing a more progressive solution. At this time, it is worth mentioning the possibility of strong storms, albeit with a lower chance of occurrence. The primary factors will be the timing of the trough with regards to peak heating, as well as antecedent cloud cover. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1232 PM CDT Fri May 31 2024 VFR conditions are expected through the TAF period at all sites. Winds will shift later this afternoon into the evening, becoming more southerly through the overnight hours. Winds will shift back towards the west by Saturday mid-morning. Impacts to aviation are not expected through the TAF period. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ DISCUSSION...Lynch AVIATION...Lynch