917 FXUS63 KFGF 080922 AAA AFDFGFArea Forecast Discussion National Weather Service Grand Forks ND 348 AM CDT Mon Sep 8 2025
.KEY MESSAGES...
- Isolated severe thunderstorms (SPC risk level 1 of 5) are possible late this afternoon and evening over west central M innesota and f far southeast North Dakota. Large hail is the main threat. Threat is AND conditional, as storms may not form.
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.DISCUSSION... Issued at 334 AM CDT Mon Sep 8 2025
...Synopsis...
Satellite is showing northeast advance of an arc of mid clouds from far southeast ND southeast toward Minneapolis at 08z. From 850 mb analysis via SPC this cloud area coincides with advance of 850 mb moisture and temperature advection due to southwest 850 mb winds of 30 kts.
This 850 mb advancement of moisture and 850 mb warm advection/instability will advance northeast today and be situated from northeast MN southwest thru west central MN and into far southeast ND/northeast SD by afternoon. 850 mb winds southwest in this zone, so advance of 850 mb moisture and instability looks to be held in place and mainly south of a BJI-FAR line. Subtle 500 mb short wave upstream moving thru southern Saskatchewan will move into eastern ND and southern Manitoba by late today. Forcing with this wave though is rather weak. What seems more noticeable is a development of a surface low in west central into central South Dakota today, with a developing frontal boundary setting up across far southeast ND into north central and northeast MN again near and south of a BJI-FAR line. South of this boundary dew pts forecast by all CAMs and global models to reach the low-mid 60s mid to late this afternoon and with high temps arounnd sfc CAPE values over 2000 j/kg are forecast near the MN/SD/ND border region.
...Isolated severe storms possible late this aftn/eve...
Models indicate elevated convection will develop by mid aftn and last into the evening focused more on the nose of the southwest 850 mb jet thru northeast MN into west end of Lake Superior. Question is will there be enough upper level forcing with 500 mb wave moving into E ND to generate a few t-storms in the more unstable airmass over our far south and southeast fcst area late in the day or evening. 30 kts 0-6 km bulk shear is there....so enough for some organized updrafts should storms form. That is the question will storms form and if they do will they grow enough to become briefly strong/severe. SPC does place parts of west central MN in marginal risk (level 1 of 5) for late today/evening conditional based on if storms form.
Lingering chance of a few shower or a t-storm may last into Tuesday depending on speed of weak boundary moving south in central MN. But otherwise warming temps aloft with 500 mb ridge developing north into central Canada while 500 mb trough moves into the western US. Postion of upper trough and potential 500 mb low in Oregon or northern California will keep higher chances for any shower/t-storm activity to our west, but as weak 500 mb waves move out from the upper trough and what looks like along the North Dakota and Manitoba border region Thursday and beyond some chances for shower/t-storms are present. Organized severe convection is not anticipated at this time.
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.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1151 PM CDT Sun Sep 7 2025
VFR conditions are forecast through 00Z Tuesday, and likely beyond. High altitude clouds will continue to gradually increase throughout the TAF period, but remain VFR. Winds will be less than 10kt through at least 17Z, with winds to 15 kt out of the south after 18Z.
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.FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None.
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DISCUSSION...Riddle AVIATION...CJ
NWS FGF Office Area Forecast Discussion