FXUS63 KFGF 020804 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 304 AM CDT Sun Jun 2 2024 .KEY MESSAGES... - There is a level 2 out of 5 risk for severe storms this afternoon and evening for the entire FA. Hazards include hail up to golf ball size, wind gusts up to 60 mph, and a few tornadoes possible. - Widespread showers and thunderstorms are expected late Monday night into Tuesday. Severe storms are unlikely. && .DISCUSSION... Issued at 304 AM CDT Sun Jun 2 2024 ...Synopsis... As the CAMs were starting to show at this time yesterday, scattered showers have begun to show up along the Interstate 94 corridor early this morning. There haven't been any lightning strikes yet, but the HREF 1-hour thunder probability does show this potential developing in the next hour or two. This is elevated convection, tied more so to 700mb warm advection and a developing 25-35 knot low level jet. These parameters lift northward, so by sunrise into mid Sunday morning most of this activity should lift into the highway 2 corridor and northward. After seeing this consistency from yesterday, have pretty good confidence with it. However, this will have implications on heating and instability for later, as the clouds and any precipitation will hold down the temperature rise along and north of highway 2 today. The NBM has caught on to this with cooler highs in these areas today. ...Severe potential this afternoon and evening... After having pretty good confidence on how convection may occur early this morning, the confidence for how things may unfold this afternoon is much lower. So why is that? First, the surface features look very weak today, versus what was there at this time yesterday (a surface low near Jamestown at 00z Monday with a trailing cold front, and a warm front extending eastward along Interstate 94). As of now, not sure there will be much of any surface low or boundaries, or it will just be a weak trough. Surface winds do look pretty gusty from the south today, but behind the so called cold front/trough they are pretty light. So there is no strong push behind this weak boundary in the 21z Sunday to 03z Monday period. Second, as mentioned in the synopsis section, morning clouds and precipitation will likely limit the convective potential across the north. CAMs yesterday had showed a nice line of storms forming over central North Dakota 21z Sunday-00z Monday, then moving into eastern North Dakota and weakening during the evening. CAMs now show an earlier and more southern track to the best severe potential this afternoon and evening. And again, this could change. To start, SPC kept the entire FA in a slight risk for severe weather. Some of the main parameters remain the same, starting with good moisture return. However, SPC did note that surface dewpoints by afternoon in the 60s might be a little too optimistic. The upper support is not ideal, but enough. The HREF is indicating maybe 1500-2000J/kg of MLCAPE across southeast North Dakota by 21-23Z Sunday, with about 35 knots of 0-6km effective shear. The better mid level lapse rates hold along the Dakotas border down into eastern South Dakota. Meanwhile, the low level jet cranks up pretty good from 21z Sunday to 00z Monday (around 50 knots), so much stronger than it is right now. However, its best focus may be into Minnesota lifting into southern Canada in the evening. CAMs seem to be latching on to one cluster of storms across northwest Minnesota during the late afternoon and early evening, feeding off the low level jet, while another cluster tries to get going from Jamestown to Oakes. As the storms from Jamestown to Oakes push east during the late afternoon and early evening, they turn linear and sag southeastward toward the better CAPE. These would be more wind producers. The HREF shows the best UH tracks developing around Barnes County about 22z Sunday, and continuing across southeast North Dakota and adjacent areas of west central Minnesota until about 03z Monday. Will maintain the inherited hazard wording for hail (although will go golfball size to match Bismarck, wind (60 mph), and a few tornadoes possible, although it may be trending more toward wind and maybe hail. ...Next event Monday night into Tuesday... The next good shortwave is still on track to move through the FA Monday night into Tuesday. This is a little faster than what was seen yesterday, so that most of the precipitation moves through during non-peak heating hours. This means there is not very much CAPE to work with. The track of the wave may favor the northern half of the FA with slightly heavier precipitation amounts now. Quarter inch amounts look pretty favorable for all areas, ranging from a 90 percent probability along the Canadian border to 60 percent along the Dakotas border. Probs for amounts greater than 1 inch range from 40 percent along the Canadian border to 10 percent along the Dakotas border. Uncertainty then comes into play for the later periods, with the potential for an upper low to linger over the Northern Plains for a few days, or slowly shift east. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1147 PM CDT Sat Jun 1 2024 VFR conditions prevail through much of the TAF period, with the primary concern being the formation of showers and thunderstorms heading into Sunday. Light and variable winds overnight are expected increase out of the south after sunrise Sunday morning. A weak shortwave will bring slight chances for mainly isolated storms across the area early Sunday morning, with little confidence in location based on upstream observations. Much higher probabilities for impactful thunderstorm development enter the forecast Sunday afternoon and evening, with strong to scattered severe thunderstorms possible. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ DISCUSSION...Godon AVIATION...Lynch