textproduct: Grand Forks

KEY MESSAGES

- Additional chances for strong to severe thunderstorms exist over the holiday weekend.

UPDATE

Issued at 1237 PM CDT Sat Sep 5 2026

Tiny vorticity max in northeastern ND continues to bring shower and thunderstorm activity to the CWA, mostly elevated with around 1000 J/kg of MU CAPE. CAMs have been absolute garbage handling this activity. There does seem to be some ripples on water vapor indicating additional shortwaves coming up the ridge in our direction. Can't completely rule out some fairly stout updrafts if we can get some destabilization between when the current convection clears out and the next weak shortwave arrives. If any convection does pulse up it will likely be poorly organized, with the main threats hail up ping pong ball sized and wind gusts to 60 mph. Confidence in convective placement and strength is low.

UPDATE Issued at 630 AM CDT Sat Sep 5 2026

Watching thunderstorm activity in north central ND and far southern Manitoba this morning. High res guidance continues to bring these stronger storms into northeast North Dakota in over the next several hours. Hazards with these storms could include hail up to 1 inch and possibly isolated wind gusts to 60 mph.

UPDATE Issued at 935 PM CDT Fri Sep 4 2026

Latest 00Z guidance generally agrees in scattered showers and thunderstorms in eastern ND overnight tonight into Saturday morning. This is driven by developing low level jet helping advect and lift higher moisture out of SD into ND.

While majority of guidance depicts convection, there are noteworthy differences in strength of storms within guidance. A cluster of guidance depicts robust thunderstorms, with the other cluster keeping storms weak. This could be attributed to uncertainties in degree of forcing within the zone of lift on the periphery of the low level jet, as well as the low level jet not being particularly strong. Should storms become robust, there is the possibility of hail given sufficient shear and instability, favorable shear orientation, as well as the elevated nature of storms.

Further expanding uncertainty is how large hail may get should hail production occur. Soundings in the forecast near storm environment have concerningly numerous analogs with very large hail at least 2 inches. While this is not the favored scenario (mainly due to expectation of forcing to sustain robust thunderstorms to be on the weaker side), it is something to be mindful of.

..Severe chances over Labor Day weekend

First of several shortwaves under the upper ridge comes in tonight, and with warm air advection, some showers and thunderstorms are possible. Main activity will be in our far western counties, although it is uncertain how far east the decent elevated instability will move. Some of the CAMs have some fairly healthy thunderstorms developing over southeastern ND after 10Z tonight, while other runs have showers or nothing at all. The HREF has some low probabilities (10 percent) of strong updraft helicity tracks early tomorrow morning, so can't completely rule out some elevated hailers but not super widespread. Another shortwave coming through Saturday afternoon or night could bring additional convective activity, but the deep layer shear is pretty unimpressive at around 25 kts. Slightly better shear and instability on Sunday over eastern ND, although much will depend on how previous convection plays out and exact timing of the embedded waves. Best shear will be Monday afternoon, although CAPE values are all over the place. In short, there will be several chances for a few isolated severe cells to develop Saturday through Monday, but exactly where and when are uncertain.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1237 PM CDT Sat Sep 5 2026

Thunderstorms exiting the KGFK area and moving into KTVF. KDVL has some lingering showers and could see some additional activity later this afternoon. Storms also seem on track towards KBJI, so have VCTS mention there but will stay north of KFAR. Model performance has been poor and not certain enough for any showers and thunderstorms impacting the TAF sites after 00Z to include at this point. VFR conditions as the convection moves away from the forecast area. Some of the models have some low stratus or fog going into the KBJI area later tonight, but probabilities currently only 20 percent so will keep VFR for now. Winds will be east to southeasterly, with gusts to 20 kts possible near thunderstorms today and in the afternoon tomorrow.

FGF WATCHES/WARNINGS/ADVISORIES

ND...None. MN...None.