textproduct: Twin Cities

KEY MESSAGES

- Multiple rounds of showers/storms today, with a chance for some strong to severe storms this afternoon.

- Cooler than normal temperatures continue today with a warming trend through the weekend back to normal.

DISCUSSION

Issued at 243 AM CDT Wed Jun 17 2026

The surface low is currently over the Dakotas early this morning. This low will move into southern Minnesota this afternoon and off to our southeast by this evening. In addition we will see the left exit region of a jet streak overhead as well as a subtle shortwave. This will provide for ample lift. The question is what does the atmosphere do with this lift? More specifically what are the thunderstorm impacts? To start he day we have a LLJ providing some much needed moisture. This has allowed rain showers to develop across the broader region. Looking towards thunderstorms we will need instability and for more organized convection, shear. We will see strong speed shear throughout the day, but the directional shear will be depend on the position of the low. The strongest shear, most typical of supercells, will be ahead of the low. This will move through most of our area during the morning. So we will see the best shear profiles during our minima of instability due to the time of day. So far this morning we have struggled to develop even elevated MU CAPE and therefore thunderstorms. The only area with some MU CAPE has been far southwest Minnesota, but even in SW Minnesota there have not been lightning strikes observed. It is farther west closer to the surface low where strikes have been occurring. So it is seeming increasingly unlikely so see much beyond rain showers this morning for much of the area, it would only be far southern Minnesota where there are chances. Attention then turns to the afternoon for storms chances. Even with the modest warming expected today, this should be enough to get 1000-2000 J/kg of CAPE. The difference here though is we have to more straight line hodographs by this point as the low continues to move east. This wold favor more multicell storms and a lower severe impact as these multicell storms tend to struggle more in these lower end instability setups. The SPC has kept a small hatched hail area in far south central and southeast Minnesota. This is the one area that might still have some directional shear to favor more discrete convection and therefore hail. On a heavy rain front, storm motions are expected to be fast enough that while heavy rain impacts cannot be rules out, it is not a major concern. By the evening the low should be off into eastern Wisconsin or the southern Great Lakes. This will lead to diminishing storm coverage as the source of lift comes to an end.

Behind Wednesday's system Thursday will see high pressure move in bringing us clearing skies. With more of a CAA setup though the sun only bring highs up to around 70 for the day. Friday will see another shortwave move in along the largely zonal flow aloft that we have seen all week. There appears to be enough instability for some thunderstorms as well once we get into the afternoon and evening on Friday. As we head into the weekend our northwesterly zonal flow starts to become more westerly and that will help temperatures warm back up to around normal (highs in the upper 70s). How much we warm still varies with GEPS and GEFS holding warmer the the EPS. GEPS still shows some 80s as we moving into the start of the next week. The EPS does have more rain chances along with cooler temperatures with the GEFS and GEPS looking quite dry. The main period EPS members highlight for rain is on Sunday and that is reflected in the NBM PoPs. However with the great spread between the ensemble systems there is little confidence in this rain at this point.

AVIATION /06Z TAFS THROUGH 12Z THURSDAY/

Issued at 1222 AM CDT Wed Jun 17 2026

For the start of the period the main area of activity looks like it will stay well to the south of the terminals. There will be rain the the north of this activity in SW Minnesota, but it will be VFR showers. As we move into late morning and afternoon aviation impacts are expected to increase. This next round of rain and some thunderstorms will have drops into MVFR and for some terminals IFR. The main drops into IFR will be with periods of heavier rainfall or thunderstorms. Some low stratus also looks to linger in Wisconsin to end this period leading to a more prolonged low MVFR/high IFR impact.

KMSP... Showers overnight into the early morning should have little impact. It will be the late morning into early afternoon chance for rain and possibly thunderstorms that will see drops into MVFR. Still some signal for possible IFR, but not enough for TAF inclusion yet. The best thunderstorm chances are still to the south of the airfield, so opted to stick with the PROB30 group for this afternoon.

/OUTLOOK FOR KMSP/ THU...VFR. Wind NW 10-20 kts. FRI...VFR. Chc MVFR/TSRA. Wind W 10-15 kts. SAT...VFR. Wind NW 5-10 kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None.