Updraft®

Dodging showers and thunderstorms on the Fourth of July

Heaviest rainfall favors southern Minnesota Thursday night

Excessive rainfall outlook
Excessive rainfall outlook Thursday.
NOAA via Iowa Emergency Management

Another holiday, another chance for rain in Minnesota.

After a beautiful Wednesday, our next low-pressure wave will push showers and thunderstorms into Minnesota for this Fourth of July.

All forecast models agree it will rain across much of Minnesota at some point Thursday. However, there are significant model differences in forecast rainfall coverage and timing.

Here’s an example.

The National Oceanic and Atmospheric Administration’s FV3 model develops scattered morning and midday showers across southern Minnesota. A more prominent cluster of thunderstorms appears around the greater Twin Cities area by 7 p.m. Thursday.

The forecast model loop below runs between 7 a.m. and 7 p.m. Thursday.

NOAA FV3 model
Finite-Volume Cubed-Sphere Dynamical Core model between 7 a.m. and 7 p.m. on July 4
NOAA, via Pivotal Weather

A few forecast models hold the rain off until later in the day Thursday. The latest European Centre for Medium-Range Weather Forecasts model suggests rain around the Twin Cities might hold off until the afternoon but continue through most of Thursday night, including fireworks time.

The forecast model loop below runs between 7 a.m. Thursday and 7 a.m. Friday.

European model (ECMWF) rainfall forecast
Precipitation model between 7 a.m. Thursday and 7 a.m. Friday
European Centre for Medium-Range Weather Forecasts, via Pivotal Weather

Overall rainfall totals look heavy by Friday morning across southern Minnesota. A wide swath of 1 to 2 inches is likely with locally higher totals.

Here’s the European Centre for Medium-Range Weather Forecasts model precipitation output through 7 a.m. Friday:

European model (ECMWF) precipitation output
Precipitation output forecast through Thursday
European Centre for Medium-Range Weather Forecasts, via Pivotal Weather

There is a risk for excessive (flooding) rainfall across much of southern Minnesota Thursday into Friday morning.

Excessive rainfall outlook
Excessive rainfall outlook Thursday.
NOAA, via Iowa State University

Let’s see if Wednesday's forecast model runs can refine rainfall timing for the Fourth of July.