Marine Weather and Tide Forecast for Rochester, MN

DISCUSSION
Issued at 254 AM CDT Mon Sep 7 2026

Increasing Rain Chances Tonight:

An upper wave currently over the Pacific Northwest is expected to eject into the Canadian High Plains through the day today. A surface low pressure center is expected to deepen as is follows a similar trajectory out of the Northern High Plains. This will tighten the pressure gradient across the Upper Midwest, increasing southeasterly winds across the region through the day. This will serve to pool moisture across the warm sector, initiating increasing pWats to over 1.5 inches. Showers and storms are expected to start developing along and ahead of the cold front late this evening and into the overnight hours as lift from both a low level jet and shortwave jet max coincide.
These storms could pose a marginal risk for hail and wind into the early morning hours, mainly across Southeast Minnesota and West Central Wisconsin but they should tend to fizzle out with time in the morning as the low level jet weakens.

Highest, Widespread Rain Chances Tuesday:

A short reprieve in shower and storm activity is expected into Tuesday afternoon as forcing becomes more nebulous and focused on the mesoscale. Development looks to increase again later into the evening and overnight hours across the southeastern half of the local area given reinvigoration of the low level jet the short wave trough axis moving through. There will again be a marginal threat for hail and wind with these storms. Given the elevated instability these storms should be able to tap into modest cloud layer shear. Another concern will be the threat for heavy rainfall later during the day on Tuesday, with continued southeast winds ahead of the frontal boundary, pWats will continue to climb into the 1.75-2+ inch range. NBM 06.19 probabilities for 1 inch of rain in a 48 hour period ending at 7 PM Wednesday were between 30-50% across the region, 5-20% for 2 inches. Overall storm motions seem to be progressive enough to keep flash flooding concerns at bay even though pWats and warm cloud depths would suggest potential for highly efficient rainfall producers. Rain will gradually push off to the south and east through the overnight hours with most places looking to be dry by 12Z Wednesday.

Drying Out, Near Normal Temperatures Into Weekend:

As the upper wave/trough axis move east, the trailing frontal boundary from the occluding surface low well to our north in Canada will sweep through the region early Wednesday. This will finally usher in a drier airmass to the region as a whole with dew points falling back into the upper 50s. A weak surface high is expected to build into the Midwest by Thursday. This, in combination with zonal flow to weak ridging aloft, will keep conditions dry for the late week period. Temperatures behind the front won't be much "cooler" but they will be a bit closer to normal in the 70s to lower 80s Thursday and Friday. The next chances for rain look to come by the weekend as another upper wave looks to potentially swing through the upper Midwest.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
Issued at 534 AM CDT Mon Sep 7 2026

Increasing south-southeast winds through the daytime hours will remain highest west of the Mississippi River Valley primarily locally in southeast Minnesota affecting KRST TAF site.
Increasing precipitation chances near the end of the 07.12Z TAF terminus, moving from west to east, will initially locally reach KRST TAF site followed by KLSE shortly thereafter. Given the longer forecast hour affecting confidence in exact timing of onset, have included PROB30 at KRST for potential impacts as further adjustment will be needed in coming forecasts.

Storm, precipitation, and impacts likely linger through Tuesday night outside of a potential temporary reprieve Tuesday late morning into the early afternoon.

ARX WATCHES/WARNINGS/ADVISORIES
WI...None.
MN...None.
IA...None.