Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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960 FXUS63 KFGF 151245 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 745 AM CDT Sat Jun 15 2024 .KEY MESSAGES... - Isolated to scattered severe thunderstorms are possible today for the Devils Lake area and portions of the northern Red River Valley. Impacts could include damaging wind gusts up to 60 mph and large hail up to the size of quarters. - Isolated severe thunderstorms are possible Sunday afternoon in the southern Red River Valley and west-central Minnesota. Impacts are possible and could include strong wind gusts and large hail up to the size of quarters. - There will be another chance for scattered severe thunderstorms on Monday, with much of the area seeing the potential for large hail and damaging wind gusts. Flash flooding is possible as there is support for persistent heavy rainfall. && .UPDATE... Issued at 745 AM CDT Sat Jun 15 2024 Showers and mainly embedded thunderstorms continue to move slowly off to the east this morning, with southerly to southeasterly winds increasing. Temperatures are hovering in the low to mid 60s with dew points in the upper 50s to low 60s. Minimal adjustments were needed this update as the forecast remains on track. && .DISCUSSION... Issued at 411 AM CDT Sat Jun 15 2024 ...Synopsis... A very active weather pattern continues across the Northern Plains and into the Upper Midwest through the next several days. Upper ridging builds into the Ohio Valley and the Eastern Seaboard starting today, which will continue into the early part of next week. As this happens, H5 troughing digs into the western Conus, facilitating a favorable pattern for repeated trough passages along southwesterly flow into the Northern Plains. Moisture will be able to flow into the area along strong 850 mb transport winds, with long fetch gulf moisture working into the northern Mississippi Valley ahead of our H5 troughs. This will set the stage for active weather to include strong to severe thunderstorms and very heavy rainfall. ...Isolated to Scattered Severe Thunderstorms Today and Sunday... Theta-e values continue to climb this morning as mixing ratios are now in the range of 11-13 g/Kg in central North Dakota. This moisture will continue working eastward into the Devils Lake Basin by early afternoon, with SBCAPE climbing upwards of 1500 J/Kg by late afternoon. Shear in the 0-3Km and 0-6Km layers remain supportive of discrete cells; however, forcing is expected to stay west of the area, with remnant strong to severe storms working into the Devils Lake Basin later in the afternoon and into the evening hours. Environmental support for discrete cells diminishes as this happens, with clusters and possibly line segments being the primary mode heading into late evening. Soundings support large hail up to 1 inch, with a more conditional threat of damaging wind gusts due to storms becoming elevated during the overnight period. For Sunday, the theta-e gradient along a lifting warm front will be our primary driver of potentially strong to severe storms. While shear in the low levels supports a mention of tornadoes, the better environment looks to stay south of the area. CAPE still looks supportive of large hail and damaging wind gusts, however, primarily for portions of the southern Red River Valley and west-central Minnesota. ...Scattered Severe Thunderstorms Monday... A stronger trough is set to bring severe thunderstorm chances back into area on Monday as moisture continues to stream into the area. Mixing ratios climb upwards of 14 g/Kg in the southern Red River Valley with values of up to 12 g/Kg for the central and northern Red River Valley. This will usher in a conditional threat of severe storms that could expand across a larger portion of the area. How much coverage we see will depend on the speed of the theta-e gradient boundary associated with a push of cooler and drier air working in from the northwest. Guidance shows a range of solutions that support anything from elevated large hail producing supercells, to potentially tornadic cells ahead of the boundary. With the slow forward movement expected with this system, we could also see a flash flood risk emerge as training storms could move repeatedly over the same area. The best chances for impacts, resides in the southern and central Red River Valley and portions of west central Minnesota; however, the position of the boundary will ultimately determine the axis of heaviest precipitation and strongest thunderstorm potential. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 625 AM CDT Sat Jun 15 2024 Scattered showers and thunderstorms are moving across the area this morning, primarily impacting KGFK and KTVF. Brief MVFR conditions are possible during thunderstorm activity due to lower ceilings and visibility. Additional thunderstorm activity moves into the area later this afternoon and evening, with MVFR CIGs possible once more. Winds are already increasing this morning and are expected to remain southerly through much of the TAF period. Wind gusts of 25 knots are possible through late this afternoon. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Lynch DISCUSSION...Lynch AVIATION...Lynch