MULTI-DAY SEVERE WEATHER THREAT

Late Thursday into early Friday morning we got our welcomed first dose of rainfall that thankfully came without much fanfare, just a beneficial drink of water. Unfortunately while more rain is coming, the likelihood that it comes with severe weather is increasing with severe weather outlooks plastered to start early next week Monday through Wednesday. Eyes are particularly on Tuesday as of now, more on that in a moment.

Analysis shows as expected a widespread 1-1.5" rain event occurred across Iowa into northern Illinois. A few places excelled with reports in the Cedar Rapids metro over 2". Des Moines was a little over that 1.5" mark. The Quad Cities generally fell within the 1.0" to 1.5" range. Good stuff!

So far this spring is one of the wettest on record in the region, and this does not include the overnight rain yet. March 1 through April 9 is the third-wettest start to spring for northeast Iowa and southwest Wisconsin. Northwest Illinois is the fifth-wettest with the Chicagoland area the wettest on record to start Spring (since 1893). We will keep adding onto this with multiple storm chances going forward.

We will have rain chances taking back off Saturday through Wednesday, with again the threat for severe weather in place. I want to jump to the bigger fish which is Monday and Tuesday as they are the most interesting in terms of an impact to the region.

Longwave pattern shows an amplified trough digging in the western CONUS Sunday through Wednesday, fully ejecting Tuesday and Wednesday through the Great Lakes region. This will have the highest severe weather potential as the greatest upper air support will be overhead. This pattern also encourages strong southwesterly flow bringing in a lot of moisture for more heavy rain and strong storms.

INSTABILITY - MONDAY

INSTABILITY - TUESDAY

INSTABILITY - WEDNESDAY

While overhead the upper-level winds are sufficient, indications are that at the surface there will be plenty of warm and moist air - fuel for severe weather. Instability looks highest Tuesday locally, but I do not want to sleep on Monday and Wednesday either. There are differences between the American GFS and the European (which I show above), but I personally like how the Euro is depicting the event and it has been a little more consistent.

Given the fact the same areas will be impacted day after day it's always worth noting how one day's storm evolution will impact the next. It could constructively influence it by introducing features like outflow boundaries to enhance the next day's severe weather, or destructively influence it with potential of lingering clouds and showers that would hamper the next day's instability.

The ingredients are there for multi-day severe weather event, and even the "O" word (outbreak) may be needed to break down the situation. It's interesting enough it may bring me up from Florida to chase the event for a few days as I unwind from Artemis II launch support.

While confidence is increasing, but not very high yet, on the threat of severe weather there is quite high confidence in rain at least. Latest forecasts are bringing in another 1-3" over the next week with the severe weather enhancing the concerns.

Unfortunately long term the pattern looks to remain active through at least next week. We could use a break, but there's not much of one in sight.

-Meteorologist Nick Stewart