


Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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282 FXUS63 KFGF 300903 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 403 AM CDT Mon Jun 30 2025 .KEY MESSAGES... - Scattered thunderstorms are expected this afternoon. Lightning and hail to the size of pennies would be the main threats with stronger storms. Scattered storms possible near Manitoba border Tuesday evening. - Severe thunderstorm chances return Independence Day (Friday) late afternoon and night. && .DISCUSSION... Issued at 338 AM CDT Mon Jun 30 2025 ...Synopsis... This upcoming week will feature a progressive 500 mb pattern with 500 mb troughs and ridges moving thru the northern tier of the US and Canada. This will lead to several thunderstorm chances today and again late Tuesday and late this week. ...Scattered t-storms today... Well defined 500 mb trough progressing southeast into northeast and central ND at 08z with a well defined moisture area and an area of scattered showers/t-storms. T-storms still occurring in SW MB despite loss of sfc heating. So enough dynamics and cold pool at 500 mb (-14C) with this to generate showers/t-storms. As the center of the trough and colder air aloft settles in NW MN and mid and northern RRV 18z-22z period do expect a decent coverage of scattered t-storms esp east of DVL-FAR-Wadena line. 0-6 km bulk shear is quite weak 20-25 kts, so organized updrafts not anticipated with cells more pulsy and updrafts short lived. MU CAPE in the 800-1100 j/kg range and steep enough lapse rates to 500 mb to bring the potential for hail to 0.75 inch in a few storms. ..Chance of t-storms late Tuesday... Next 500 mb feature is more of a short wave vs trough and will move into Alberta later today and produce some storms in between Calgary and Edmonton. This wave is forecast to move into SW MB around 00z Wed and 0-6km bulk shear with this is 35-40 kts and MUCAPE again in the 1500 j/kg range in SW Manitoba into far northeast ND. Thus t-storms should develop and knowing its northwest flow aflot and with higher instability and shear, a few storms possible. 00z GFS is most aggressive with this feature while ECMWF/Canadian a bit tamer and more north toward Winnipeg. So spread low pops a tad farther south than NBM into NE ND/NW MN. ...Late week chance of storms... 500 mb ridging builds into the area Thursday-Friday ahead of next stronger short wave that will move in from California into the high plains as flow at 500 mb becomes southwest temporarily. Riding aloft and thermal 850 mb ridge over the area will bring much warmer temps with highs into the 80s and low 90s Friday the 4th with dew pts likely into the 70s in many areas. NBM probably a bit low. MUCAPE values could exceed 3000 j/kg (35 pct chance), but within the 500 mb ridge will be a warm nose at 700 mb with temps 13C. Models disagree with timng of short wave and associated sfc front/trough moving thru. GFS a tad faster with system and has more development 18z-21z vs ECMWF has development farther west in west ND 18z-21z but then develops a cluster of storms and moves thru 00z-06z. Basic severe weather paramters would along with machine learning guidance (mostly from yesterdays models as 00z guidance that far out not in yet) that severe weather is possible. This would depend though on a likely the CAP breaking, which is not guaranteed. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1156 PM CDT Sun Jun 29 2025 Tonight will hold winds less than 10 kt, and dry conditions at TAF sites. Sunday will see MVFR ceilings after 12Z along with an increase in northwest winds again gusting to around 20kt. There is around a 50% chance for scattered showers and thunderstorms within Minnesota between 17Z-03Z tomorrow. This may impact sites like KTVF and KBJI during this period - added VCTS to note this. Not anticipating significantly gusty winds with these, with main hazard remaining lightning. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ DISCUSSION...Riddle AVIATION...CJ