


Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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321 FXUS63 KFGF 290832 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 332 AM CDT Sun Jun 29 2025 .KEY MESSAGES... - Scattered thunderstorms are expected Monday afternoon. Lightning and hail to the size of nickels would be the main threats with stronger storms. - Severe thunderstorm chances return Independence Day (Friday) into next weekend to parts of the region. && .DISCUSSION... Issued at 332 AM CDT Sun Jun 29 2025 ...Synopsis... An open mid level trough is moving over the Northern Plains, with the main center over the Canadian prairies. Deeper moisture and instability have been pushed to the southeast while a weak cold front is moving through the region. Elevated instability and at least some lingering moisture/forcing will support isolated to widely scattered showers and a few rumbles of thunder today, but impacts will be minimal. The mid level trough eventually deepens to the east Monday and cyclonic northwest flow brings a period of scattered showers and thunderstorms through the afternoon. Ridging is expected to dominate the pattern over the Northern Plains Tuesday through Thursday, with seasonably warm temperatures and much lower chances for measurable precipitation. As this ridge flattens ensemble clusters show a shift to westerly or low amplitude southwest flow across the Northern Plains by Friday which persists through the weekend, and the pattern may become more active once again as a result. In addition, the increase in BL moisture and heights across the central US raises the potential for heat impacts. Though current NBM keeps heat risk in the moderate category late week into the weekend. 75th percentile of NBM members would support the potential for higher impacts. ...Strong storm potential Monday afternoon... The signal for scattered convection is consistent with guidance with higher coverage for showers shown to be closer to the deepening trough in our northeast during peak heating based on NBM and HREF. While drier NW BL flow keeps BL in the upper 50s and lower 60s, ML CAPE is still shown by guidances to increase to the 1000-1500 J/KG range during the afternoon. While effective shear may be 30-35kt in some areas, CAPE profiles will tend to be skinny and marginal as mid level lapse rates are weak (less than 7 C/km). This lowers the risk for severe convection, but may support a few strong cores and hail to the size of nickels during the afternoon period. The coverage of lighting activity (30-50%) does raise the potential for impacts to outdoor activities during the afternoon even if hail becomes less of a concern. Loss of peak heating and decoupling will result in shower/thunderstorm activity quickly ending early evening. ...Severe thunderstorm potential Independence Day weekend... The shift to west or southwest flow would allow for a return to higher BL moisture return and higher instability as progressive waves move into the region. These specific shortwaves carry lower predictability and individual ensemble members show high variance in timing/evolution that ultimately will impact evolution of any severe risk in our region. All machine learning systems have at least a signal for severe risk (5%) across the Northern Plains and our CWA with some (FengWu/Pangu) showing 15% contours by Friday within parts of the region. At this range predictability is too low to zero in on specific impacts/coverage, however anyone with plans for the holiday weekend should monitor updates. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1202 AM CDT Sun Jun 29 2025 Chance for thunderstorms has ended for the area. VFR conditions will prevail throughout the TAF period. Winds will be variable less than 10kt before 12Z increasing out of the northwest to 25kt after 16Z Sunday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ DISCUSSION...DJR AVIATION...CJ