textproduct: Twin Cities

KEY MESSAGES

- A major pattern shift will occur this weekend. Extreme heat and humidity are expected to build Sunday persist through next week. Highs 95 to 100 and dew points in the 60s and 70s will send heat indices to dangerous levels Monday.

- Periodic chances for thunderstorms beginning Saturday night and continuing through much of next week, but those chances are trending down.

DISCUSSION

Issued at 335 AM CDT Thu Jun 25 2026

A bank of low clouds continues to progress southwest across eastern MN and western WI early this morning. Some patchy fog has developed beneath it, but most locations are reporting unrestricted visibilities. The low clouds will linger into mid morning before lifting and scattering late morning. The rest of the day will feature diurnal cu, light winds, and pleasant temperatures in the 70s.

Southeast surface flow will keep a relatively dry airmass in place Friday and Saturday and a warm front will remain south across the Mid MS Valley to central Plains. The warm front will approach Saturday night. A strengthening LLJ and rapid moisture increase with steepening mid level lapse rates and sufficient deep layer shear will result in thunderstorm chances. However, strong capping may limit development and models have been trending drier. Any storms that manage to develop Saturday night may linger into Sunday morning before the warm front lifts north.

The passage of the warm front Sunday will result in a major pattern change next week. A stout EML and very warm temperatures aloft (+16C or warmer at 700 mb) will provide an impossible cap to break in the warm sector Sunday afternoon through Monday. Progged temperatures remain quite hot Sunday and especially Monday. Depending on the timing of the front and the decrease of convective activity early in the day, highs Sunday may reach the upper 90s across southwestern MN. This is looking more likely as thunderstorm chances trend down. By Monday, thermal ridging characterized by 925 mb temps of +29 to +32C still appear likely to engulf much of central and southern MN and western WI. Highs in the upper 90s to lower 100s can be expected with this type of airmass. Deterministic guidance continues to bring highs nearing 100 across southern and western MN, including the Twin Cities. In addition, dew points will rise into the low to mid 70s, especially across eastern MN and WI, potentially pushing heat indices into the 103 to 108 range. Deeper mixing across western MN should allow dew points to fall several degrees short of those levels, but that may also allow temperatures to climb even higher. In fact, guidance indicates 925 mb temps near the SD border as hot as +34C, which would support highs in the mid 100s. Monday is expected to be the first dangerous day for heat of the season, but may only be one of many next week.

Guidance has been consistent with bringing a weakening cold front into western MN Monday evening. The cap should ease as the EML weakens and exits to the northeast late in the day. Rich theta-e air will provide a very unstable airmass. However, the front is not depicted as progressive as it has been in previous days and may washout entirely before reaching the better low level moisture across eastern/southern MN. The weak forcing along the front, drier boundary layer in western MN, and some remaining capping casts doubt on whether development will occur. Provided thunderstorms struggle to develop, Tuesday will be another rather hot day and may be warmer than currently forecast.

The rest of next week will feature an intense 500 mb ridge (596-598 dam) parked over the Ohio Valley. This is a shift north from previous forecasts. The result would be a drier and hotter forecast through next week with thunderstorms remaining north and west. Things will dry out very quickly if we dodge thunderstorm chances.

AVIATION /18Z TAFS THROUGH 00Z SATURDAY/

Issued at 1208 PM CDT Thu Jun 25 2026

Some lingering MVFR stratus this afternoon across mainly western Wisconsin, but there is also a band of low stratus across Minnesota that has impacted AXN and MKT. Overall trends favor an increase to VFR by this evening, for where it isn't already VFR. Winds will be at or below 10 kts from the N/NE today becoming light and variable tonight. With the system from the past few days fully to the east, we are not expected a third day in a row with morning IFR from low stratus.

KMSP...No additional concerns.

/OUTLOOK FOR KMSP/ SAT...VFR. Wind SE 10-15G25 kts. SUN...VFR. Chc AM SHRA/MVFR. Wind SE 10-15G30 kts. MON...VFR. Wind S 15-20G30 kts.

MPX WATCHES/WARNINGS/ADVISORIES

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