textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Gusty northwest winds in the wake of a cold front will diminish this evening.

- Easterly winds will keep lakeshore temperatures cooler than inland areas Wednesday through Friday. Expect a gradual warming trend Saturday through Memorial Day.

- Rain chances return Friday afternoon and night (40-60%), with much smaller chances the rest of the holiday weekend.

SHORT TERM

Issued 325 PM CDT Tue May 19 2026

Tonight through Wednesday Night:

Gusty west-northwest winds in the wake of the surface cold front will gradually diminish through late evening as an inversion sets up. Cloud cover is more uncertain, but there should be a thinning/clearing trend from west to east overnight. The upper wave will swing across WI much later than the surface front, so temps will remain on the milder side during the overnight period, ranging from the upper 40s southeast to the lower 40s toward central WI.

By 12Z/7AM Wed, the mid level trough and 850mb front will be stalled over central WI. Meanwhile, a shortwave tracking across the Plains will push into southern WI by midday. The interaction of the 850mb front sliding south and the incoming shortwave will help colder air rush down the lakeshore quicker than inland (back door cold front) during Wed morning. This should also bring a period of low clouds to the lakeshore and slightly higher but still widespread clouds to inland areas. Temps will remain cooler near the lake, with highs ranging from the mid 50s lakeshore to the lower/mid 60s well inland.

Despite surface high pressure sitting over the Upper Great Lakes, the mid level shortwave and right entrance region of the upper jet should keep at least mid level clouds around. Without the clearing and with a persistent light easterly breeze, our frost potential is very low. The forecast low temps are between 39 and 42. This is slightly up from the previous forecast and nearly lined up with the 50th percentile of model solutions.

Cronce

LONG TERM

Issued 325 PM CDT Tue May 19 2026

Thursday through Tuesday:

The upper level pattern will be very similar to Wed on Thursday. The mid level clouds may be even thicker. A steady easterly breeze will keep lakeshore temps cooler than inland (similar temps as Wed). Thursday night lows will be in the lower to mid 40s. The surface east winds will remain steady through Friday, and this may help to hold off the rain. Models are trending later with the arrival of our next chance for precip.

An upper trough progressing through the Northern Plains Thursday night into Friday will swing into MN Fri evening. Meanwhile, a weak low crossing MO and IL will slide into Lower Michigan. Southern WI will be in the middle of those features, but weak warm air advection and the synoptic forcing could be enough for scattered light showers. The thunder threat is looking lower now due to the probable timing into the evening/overnight. There is no severe threat. The ECMWF has a wetter look to the Fri nt/Sat period than the GFS at this time. We will keep a close eye on this for the holiday weekend.

The upper trough will be crossing WI on Sunday and this will bring a chance for showers of the scattered, pop-up variety. If the low level lapse rates are steep enough, a few rumbles of thunder look possible Sunday afternoon. This would not be an all-day wash-out. Monday weather looks quiet right now, as we will be between systems.

There will be a warming trend with the temps through the Memorial Day weekend, with highs around 70 Sat, 75 Sun, and 80 Mon.

Cronce

AVIATION

Issued 325 PM CDT Tue May 19 2026

Expect MVFR ceilings and gusty northwest winds behind a cold front that is currently crossing southeast WI (now near Milwaukee). Ceilings should lift to VFR late this afternoon and then disperse tonight as skies gradually clear as high pressure works into the region.

Clouds below 5000 ft should be present on Wednesday, especially closer to Lake Michigan where a period of MVFR ceilings are expected as the northeast winds develop in the morning. The northeast winds will expand inland through early afternoon.

Cronce

MARINE

Issued 325 PM CDT Tue May 19 2026

Gusty westerly winds are developing in the wake of a cold front this afternoon. Gusts up to 30 kt will be possible right behind the front and then winds will gradually diminish overnight. High pressure will then move into the northern Great Lakes on Wednesday. Modest northeast winds are expected Wednesday afternoon through Thursday, especially over the south half. Winds will remain easterly through Saturday as strong high pressure tracks across Ontario and Quebec and a weak low pressure trough sets up in the Plains.

The Small Craft Advisory for the nearshore was extended until 7 PM CDT this evening due to gusty west-northwest winds. Northeast winds will develop Wednesday morning and persist through Saturday. This will build high waves in the nearshore areas by Wednesday afternoon. Another small craft advy will be needed.

Cronce

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 7 PM Tuesday.