A NEW SHERIFF IN TOWN...

The central Midwest has really been in a rut the past two months thanks to a weather pattern that has been exceptionally consistent. Big Great Lakes highs and a NW flow have combined to keep temperatures cool and precipitation lighter than what is usual in May and June. One of the primary reasons has been the lack of heat and water vapor (humidity) that typically comes with late spring.

Sunday's recent cold front that brought a touch of fall to the area Monday (it was only 67 here in Dubuque), thrust dew points into the 40s with a brisk NW wind.

That produced a relative humidity of 39 percent in Cedar Rapids Monday afternoon! The air was even drier in Missouri, where humidity was as low as 27 percent. That's some bone dry air for June 9th.

The late afternoon GOES satellite imagery shows the big spiraling upper air low drawing the cool, dry air southward into the central U.S. Any deep moisture is confined to the area ahead of the cold front shown arcking from Ohio, to southern Indiana, into NE Texas.

COME AND GET THE DEALS AT MY GALENA AIRBNB

My 5-STAR AIRBNB just outside of Galena still has some openings this summer. All of our ratings are 5 star! We take pride in the amenities and the cleanliness. If you book now, we'll take off $200, and we can eliminate AIRBNB fees and additional costs that will save you big bucks. Other discounts apply. Call or text Carolyn at 563-676-3320 for our best deal of summer. See more at https://www.littlewhitechurchgalena.com/

A NEW SHERIFF IS COMING TO TOWN

The big news is that a new sheriff is coming to town, and he's bringing a posse comprised of warmer, more humid weather. That will drive instability and some gunfights that could feature thunderstorms, heavy rain, and a risk of severe weather. This is a pattern that looks ripe for MCS development (mesoscale convective systems) which from a climatological standpoint reaches its peak in June and July. Potentially, it's the best set up I've seen on the charts so far this season for widespread convection. At 500mb, watch how we flip the pattern between now and Sunday. The baroclinic boundary between summer and spring is shifting north. The "ring of fire" is going to be meandering around the Midwest.

The ring of fire is basically the northern edge of the storm track. The interaction of warm humid air to the south vs. cool dry conditions to the north takes place in this zone. Energy likes to ride the boundary and act as the kicker for storms along it. Over a week's time, several rounds (clusters) of storms can form. These big convective clusters can crank out the rain.

Before anything happens, moisture must get back onto the pattern, and that appears to happen rather quickly the next 48 hours. Notice the west to east boundary setting up over Iowa and northern Illinois Thursday, where water vapor reaches 1.50 to 1.80 inches.

A week later, Thursday (June 19th), some places are pushing levels of 2 inches. That's a critical threshold for the development of storms that can easily dump 2–4 inches of rain in one fell swoop. It's impossible to say precisely where, but somebody within that environment is likely to get some significant rains.

All told, the EURO the next 2 weeks shows this for rainfall potential. Some amounts near the Minnesota border are over 5 inches.

The GFS is really aggressive during the same time frame with some 9 inch totals in NC Iowa. Most of my counties near and west of the Mississippi are shown with 3-6 inch amounts! The GFS is known to be biased on the heavy side of precipitation totals, so I'm inclined to lean more towards what the EURO is suggesting.

Much like snow forecasts, you can't take the numbers verbatim at this distance, but you can see some serious trends on the table for heavy rain nearby. By the way, the Weather Prediction Center has a marginal risk of excessive rainfall 3 consecutive days in the region. Here they are by day.

Wednesday night

Thursday

Friday

The precipitation forecast from WPC the next 7 days is a wet one from about I-80 north.

The EURO ensembles, (over 50 members) show this for rainfall the next 6 days.

The EURO ensembles depict an 80 percent chance of at least an inch of rain in that 6-day period in my northern counties.

There's a 50-60 percent chance of 2 or more inches of rain in that same general area.

Further down the road, the Climate Prediction Center has even issued slight risk outlooks for both heat and heavy rain June 17th through the 20th.

Meantime, Tuesday promises to be a fine day with temperatures in the upper 70s to low 80s with mostly sunny skies and a more gentle west wind. Wednesday, a significant surge of warm air and moisture arrives that lasts through Friday. Highs should reach the 80s in the central and south. However, with the front meandering around the north, thunderstorms that develop Wednesday night that will send debris clouds, outflow boundaries, and potentially additional rounds of storms into the north. This could limit highs there to the upper 70s to low 80s Thursday and Friday.

The nearly stationary then front slips just south of the area Saturday and Sunday. This should provide a couple of days with cooler, drier air and allow a reprieve from any storms, especially Sunday and Monday. That is a temporary trend as the fronts inches back into the region early next week with more storms and warmer temperatures. If you see the new sheriff around, give him my regards. Roll weather...TS