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Strong storms possible late Saturday; turning warmer

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What a raw September day Friday has been: chilly afternoon temperatures just in the 50s to low 60s, low clouds, periods of drizzle, light showers and that incessant wind gusting to at least 30 mph for much of Minnesota.

Full harvest moon Friday night

Lingering scattered showers over northeastern Minnesota should diminish Friday night. Much of the rest of the state will get clearing skies.

Duluth weather radar shortly after 5 p.m. on Friday
Duluth weather radar shortly after 5 p.m. on Friday
Duluth National Weather Service

Clearing skies could offer up a nice view of the full harvest moon. The moon is at apogee. That means that it is at its farthest point from the Earth in its orbit and will appear a bit smaller than usual. But full moons always look large and lovely as they rise or set.

Storms later Saturday

The weather term to learn for Saturday is “warm advection.” That means warmer air coming our way for a welcome warmup. High temperatures will range from about the mid-60s in the north to the upper 70s in the south. The Twin Cities should warm to about 76.

Tied to the warm southerly flow will be an increase in dew points as the moisture level increases.

Combine the warmth and moisture with sunshine and an advancing weather system from the west and the result is likely to be the brewing of scattered thunderstorms for mainly northern and eastern parts of the state.

Forecast weather map for Saturday
Forecast weather map for Saturday
NOAA Weather Prediction Center

Some thunderstorms might become strong or even severe in parts of central and southern Minnesota by late Saturday afternoon or evening. The Storm Prediction Center has issued a marginal risk of severe weather for those areas for Saturday and Saturday night.

Risk of severe weather for Saturday and Saturday night
Risk of severe weather for Saturday and Saturday night
NOAA Storm Prediction Center

Warm and rain-free Sunday through Tuesday

Sunday looks like it will be a mostly sunny, warm day for most of Minnesota. Afternoon highs should range from comfy mid-70s in the north to the low 80s in the south. The Twin Cities should reach about 80. But do dress for highs just in the 60s near Lake Superior.

If you usually enjoy our July weather, you will love Monday and Tuesday. Temperatures will be very warm for mid-September, with high temperatures generally 10 to 15 degrees warmer than normal. That means lots of 80s for much of the state. Some low 90s are possible in the south.

The Twin Cities could easily reach the mid-80s both days. That might feel extraordinarily toasty since the official Twin Cities temperature has not touched 80 since Aug. 20.

And expect noticeable humidity.

Storms beginning midweek

Long range forecasts are indicating periods of showers and thunderstorms beginning Tuesday night or Wednesday.

Tropical update

Tropical Depression Nine is forecast to strengthen a bit to become Tropical Storm Humberto as it passes the northern Bahamas. It should then remain off the Florida coast but might send heavy rains to some coastal areas.

Forecast track of center of Tropical Storm Nine
Forecast track of center of Tropical Storm Nine with cone of uncertainty
NOAA National Hurricane Center

The forecast calls for Humberto to make a sharp right turn by late Sunday and become a hurricane as it heads generally toward Bermuda next week.