Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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157 FXUS63 KFGF 131144 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 644 AM CDT Thu Jun 13 2024 .KEY MESSAGES... - Unsettled period heading into next week with 500 mb trough west and ridge east and area in southwest flow aloft. - There is a 15 percent probability of another round of severe thunderstorms on Monday. && .UPDATE... Issued at 642 AM CDT Thu Jun 13 2024 Skies clear over the fcst area as we approach 12z. Upper wave is north and northwest of area and approaching Brandon MB. It will move southeast and generate isold-scat t-storms midday and aftn in far NE ND and NW MN per forecast. && .DISCUSSION... Issued at 234 AM CDT Thu Jun 13 2024 ...Synopsis... For today, we will be dealing with a 500 mb low over the Manitoba lakes and a short wave which is well seen moving on the south side of the upper low near Yorkton SK. This wave will move east-southeast toward toward Lake of the Woods region. 500 mb temps in the -17/-18C range near the ND/MB border and into NW MN along with daytime heating into the 70-75 range will create MU CAPES in the 500-800 j/kg range, with 20 pct chance of MU CAPE in the 1000-1100 j/kg range near Roseau and Baudette. Bukfit sounding profile for BDE shows that steep lapse rate 7.5 C/km. All of this is sufficient for scattered thunderstorms to develop today Langdon to Thief River Falls to Bemidji area north. Pea size hail wouldnt be out of the question from some storms, but expect non-severe. This follows Day 1 SPC outlook as well. Scattered storms diminish early this evening and tonight into most of Friday look dry with clear to partly cloudy sky as the colder air aloft move east. ...Unsettled period into next week... 500 mb ridging builds into the northern Plains Friday night but the building ridge quickly shifts east toward the Ohio Valley and Mid Atlantic region Sunday and holds there thru most of the next week. This will set the region up in a southwest flow aloft with periodic short waves moving northeast in the flow through the area giving chances for showers and thunderstorms. Position of front will be critical to where any severe threat lies with ECMWF remaining slower to advance 500 mb trough to our west east vs GFS. Per SPC discussion on days 4-5 severe threat will side more toward a slower ECMWF progression. That would leave south/east half of the fcst area in some strong/severe threat early next week, while significantly cooler air and more showery weather occurs west central/northwest into north central ND incl Devils Lake region. From Grand Ensemble in DESI the probs for more than 1.5 inch of rain Sun-Wed next week is highest in warm sector due to more convective nature of the rainfall...roughly over the southeast fcst area and southeast from there toward the Twin Cities and up toward Duluth. ...15 pct probability of severe weather next Monday... SPC in its Thu AM update kept a 15 pct prob of severe in the RRV and MN for Monday. Uncertainity on frontal location means no outlook for Tuesday. But there will be sufficient instability in the warm sector Monday with ECMWF maintaining a stormier outlook vs GFS which pushes warm unstable airmass far south and east. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 642 AM CDT Thu Jun 13 2024 Clear sky at 12z but expect some CU to form near the 4-6k ft agl level by late morning and thru the aftn, esp north. Few scat t-storms as well but timing and location uncertain enough to avoid putting any in TAF site (esp TVF) which would have a higher chance than the rest. West-northwest winds increase to 12-20 kts today with gusts 25 kts . && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Riddle DISCUSSION...Riddle AVIATION...Riddle