Tracking rain and thunder overnight into Friday morning

A narrow band of locally heavy rainfall is possible

NOAA WRF model
National Oceanic and Atmospheric Administration’s Weather Research and Forecasting model between 2 a.m. and 8 am Friday
NOAA, via Tropical Tidbits

Friday morning’s rush hour may be splashy and thundery in the Twin Cities and parts of central Minnesota.

A warm front is sparking scattered rain and thunder cells across Minnesota. The frontal zone favors a narrow band that could produce some locally significant rainfall into early Friday.

The National Oceanic and Atmospheric Administration’s Weather Research and Forecasting model is one of several that track a narrow band of storms from North Dakota into central and southern Minnesota overnight into Friday morning.

The most favored window for rain and thunder in the greater Twin Cities area is between about 5 a.m. and 9 a.m. Friday morning, just in time for morning rush hour.

Localized rainfall totals

Since rainfall bands with the frontal zone will tend to be narrowly focused, rainfall totals through Friday morning may be highly localized.

Some of us will get little or no rain overnight. But some of us who get under these narrow but heavier rain and thunder bands may pick up more than an inch of rainfall.

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NOAA’s WRF model lays out a narrow but heavy stripe of rainfall from near St. Cloud southeastward through the eastern Twin Cities toward Rochester. The model suggests 1 to more than 2 inches in places where heavy rain cells could possibly train over the same area.

NOAA WRF model rainfall
NOAA WRF model rainfall
NOAA, via Pivotal Weather

NOAA’s High-Resolution Rapid Refresh model paints a similar stripe of heavy rainfall. But this model shifts the zone slightly west of Interstate 94 through the southwestern Twin Cities area.

NOAA HRRR model
NOAA HRRR model rainfall
NOAA, via Pivotal Weather

So you can see how in a narrowly defined rain zone like this a small shift of just 10 to 20 miles could mean the difference between heavy rain and little or nothing.

NOAA’s Weather Prediction Center recognizes the potential for locally heavy rainfall. They have included much of southern Minnesota in a marginal risk for excessive rainfall totals Friday.

Excessive rainfall risk
Excessive rainfall risk
NOAA, via Iowa Emergency Management

So expect a potentially wet start Friday!