Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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889 FXUS63 KFGF 041725 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1225 PM CDT Tue Jun 4 2024 .KEY MESSAGES... - Thunderstorms will persist through the afternoon. Isolated severe thunderstorms are possible in Northwest Minnesota from 12 pm to 5 pm, with up to 1 inch hail, wind gusts up to 60 mph, and tornadoes. - 40 to 50 mph wind gusts with additional showers and thunderstorms are anticipated Wednesday, with 35 to 45 mph wind gusts and isolated showers on Thursday. && .MESOSCALE... Issued at 1225 PM CDT Tue Jun 4 2024 A cold front noted in current radar from Fargo to Thief River Falls is sweeping east across northwest Minnesota this afternoon with efficient heating ahead of it up to a warm front from GFK to BJI. MLCAPE > 500 J/Kg in SW North Dakota and WC Minnesota is already noted in RAP mesoanalysis with this expected to climb to 1000-1500 J/Kg ahead of the front. Eff bulk shear of 30- 40 kts parallel to the front will lead to initially isolated cells growing into clusters. These initially mini supercell type storms will be the main concern for producing severe weather as looping low level hodographs with 0-1 SRH over 100 m^2/s^2 will favor rotating storms. The surface warm front is expected to surge north to the intl border through the early afternoon with the severe threat following suit. Main threat for any tornado activity seems to near HWY 2 and north this afternoon and the cold front clearing the western extent of the threat as it moves east. && .DISCUSSION... Issued at 245 AM CDT Tue Jun 4 2024 ...Synopsis... The expected 700/500mb wave, 850/700mb warm advection, and a strong low level jet are currently providing the main lift for the complex of showers and storms moving into the western FA. These features will continue to push slowly eastward today. The upper low or lows will eventually set up across southern Canada toward the Great Lakes, setting the stage for a windy Wednesday and Thursday. There is much more uncertainty beyond that, but no big precipitation producers appear at this point. ...This morning... As of 2 am, there was a long line of showers and thunderstorms extending from Western Manitoba all the way down into Nebraska, moving eastward. It appears there must be a compact wave within this area just northwest of Jamestown, where there seems to be some counter-clockwise spin to the echoes. Believe this is why the models have been showing the highest potential for precipitation amounts of 1.00 inches or more, mainly north of a line from Valley City to Baudette. The echoes are weaker and not as widespread to the south of this line. As mentioned above, the low level jet is pretty strong (35 to 50 knots) feeding into this complex, and precipitable water values are around 1.3 to 1.4 inches. Not too much instability around for this time of the night, but will continue to monitor this area. ...This afternoon... As mentioned yesterday at this time, there is a conditional threat for severe storms east of the Red River Valley, mainly from 1 pm to 4 pm this afternoon. The main hazards would be hail up to 1 inch and wind gusts up to 60 mph. It is conditional, as there is a lot of shower/storm activity going on now (with thick clouds too), which will continue through the morning. If some decrease to the clouds can occur later this morning into the early afternoon east of the Valley, some better instability could develop. As it stands, some of the CAMs are indicating afternoon highs to the east of the Valley approaching the upper 70s to around 80, with surface dewpoints climbing to the mid 60s. This is definitely the high end though, even more so if the clouds/rain hold down any heating there. So the two scenarios for today (which seem to be shown by the HREF UH tracks), are first that the clouds/rain hold, and any severe storms fire east of this FA...or second, a brief window of decreasing clouds occurs and enough instability develops that a few severe storms fire east of the Valley from 1 pm to 4 pm. ...Wednesday and Thursday... There is still a consistent showing in the NBM and other ensembles for the 700/500mb low to stagnate across southern Canada to the Great Lakes. This sets the stage for a windy Wednesday and Thursday, although Wednesday looks slightly more gusty at this point. Showers and thunderstorms are possible Wednesday, with just showers Thursday. The most wind and shower/thunder activity would be during the afternoons of both days. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1225 PM CDT Tue Jun 4 2024 Storms will continue east this afternoon with the cold front already east of GFK, FAR, and DVL thus only TVF and BJI under threat for severe convection this afternoon through 23z. Heavy rain with MVFR ceilings will be the main concern in these areas. Winds behind the front to 15mph and gusts to 25-30mph are possible. Winds calming this evening before increasing again tomorrow morning with gusts to 40 mph west of the valley and up to 30mph in MN. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ MESOSCALE...TT UPDATE...MM/TT DISCUSSION...Godon AVIATION...MM