St. Cloud, MN Weather Forecast

Some Important Rain Lately, But Need a Lot More

We've put up with nearly daily thunderstorms (sometimes twice a day) for more than two weeks. There have been problems, like during the local flooding and large hail during the July 4 storms and the tornado in Floyd Lake on July 6. Still, the most important part of these storms is the large area with more than 2 inches of rain (yellow) with some areas over 5 inches (red on the NWS Water Prediction Service Minnesota rainfall map when you set the date to yesterday and the period to last 14 days). Still, thunderstorms leave gaps in the heavy rainfall. The St. Cloud Sky Central Airport only got a piece of the heavy rain on July 4 (the west side of Waite Park got a quarter inch or less and my house in Sartell got zero), so there has been a total of 3.14 inches since June 23.

Since we were more than 6 inches behind on rain since last August, there is still a lot of catching up to do. And, making up a large rain shortfall is more difficult during the summer, since the water loss to evaporation is highest when the temperatures are the highest. Note that the latest US Drought Monitor, reflecting rainfall through Tuesday, will be out later this morning. Expect some easing of drought conditions, especially in southern Minnesota, in the new product.

Potential First Heat Wave of Summer Begins Sunday, Perhaps Saturday

However, the major weather pattern change to much hotter weather during the weekend is still on track. That hot high, the clockwise circulation over New Mexico, Oklahoma, Colorado, and Kansas (see College of DuPage North America mid-level water vapor loop), is expected to strengthen and push northward to I've mentioned earlier in the week means that the area of daily and especially nightly storms will push to the central Rockies by the weekend and into the Northern Plains by early next week. Underneath that high pressure area, afternoon temperatures were commonly in the 90's and 100's yesterday (see yesterday's 4 PM NWS WPC North America zoom-in map). Minnesota should expect highs possibly approaching 90 by Saturday and into the 90's by Sunday. The latest forecasts have kept the high in place over the Northern Plains well into next week. That would tend to keep the northern part of the hot air, where showers and thunderstorms and leftover clouds are more likely, either near the US-Canada border or into the Canadian Prairie Provinces. If this forecast change works out, then we are likely to see a heat wave, at least three straight days with a high of 90 or higher (only 90-degree high so far was on May 27). There may not be much of a chance for leftover clouds or even thunderstorms through much of next work week.

Uncomfortable Humidity, But Not as Steamy As Last Hot Shot

The air that will be here won't be the air near the front, so I don't expect the oppressive middle 70's dew points we had on June 29. Instead, the dew points will most likely remain in the uncomfortable 60's from now through the hot period. That, combined with highs well into the 90's, would still produce at least heat advisories and a few extreme heat warnings (see NWS Heat Risk Forecast, which doesn't have the potential for a longer hot period), especially if parts of northern Minnesota also remain hot (since fewer homes and businesses have air conditioning).

Check Out Heat and Sunshine Safety

So, this would be a good time to review both how to prepare for intense heat and how to protect yourself from overexposure to the sun.

Scattered Storms Possible Before Heat Moves In (Friday Night?)

Between now and the start of the heat wave (most likely Sunday), we will have some chances for showers and thunderstorms. Yesterday's storms developed along the southern edge of the early morning storms (see College of DuPage continental US clean infrared satellite loop), so they affected Iowa, Nebraska, Wisconsin, and southeastern Minnesota (see College of DuPage north central US radar loop). However, the next storm in western Canada (counterclockwise circulation on the College of DuPage North America mid-level water vapor loop) pulled another batch of the hotter air over the top of the warm and humid air to the north, so another wave of showers and thunderstorms developed in Montana, and spread into the Dakotas and the western parts of Nebraska and Colorado (see College of DuPage continental US clean infrared satellite loop). As the night went on, notice that the storms from South Dakota southward weakened and only the storms reaching North Dakota maintained their strength (still have yellow, higher, tops than the storms further to the south). In the upcoming weather pattern, that trend should continue as the hot high will produce a plume of very warm air at 5,000 to 10,000 feet above the ground. That will tend to suppress thunderstorms in the hot air, so thunderstorms should trend northward.

Still, that process will take some time. That's why I still have a 30 percent chance for thunderstorms as the hot air approaches Minnesota on Friday afternoon and Friday evening, with still a 20 percent at a Saturday or early Saturday evening storm (see Days 2-3 of the NWS WPC quantitative precipitation forecast)

Warmer and Still Humid Today and Tomorrow

Otherwise, we will see high temperatures return to the 80's today and tomorrow since we will have more sunshine than yesterday. Dew points won't really drop that much, so they will remain in the uncomfortable 60's with only a chance for a near 60-degree low the next two nights.