Wednesday, 11:40 a.m.
Another day of heavy rain occurred in the Gulf Coast area, with Louisiana over to the Florida Panhandle bearing the brunt of the heaviest rains over the past 24 hours. Parts of Louisiana picked up 2-4 inches of rain, but they were hardly alone in the wetness. The main low pressure area tracking from Oklahoma toward Illinois brought heavy rain to northern Illinois, resulting in minor flooding overnight and early this morning.
If you examine the upper levels of the atmosphere, it's a pretty weak upper-level low raising this ruckus:
The low levels of the atmosphere, however, are rich in moisture with an unabated flow from the Gulf of Mexico right into the Ohio Valley and mid-Atlantic states. Dew points are at least in the mid-60s in most of these places, and that's helping to fuel showers and thunderstorms at the drop of a hat. As we saw in parts of Maryland and Pennsylvania yesterday and again early this morning, that can also lead to some sporadic downpours well removed from the parent storm or upper trough!
This will go on with this particular feature for a couple of days yet. For the most part, areas of the the Ohio and Tennessee valleys will be out of the heavy action after this evening. There will still be some localized downpours through tomorrow in the East, but less so on Friday. Most of the heftier rains after that will be relegated to New England.
We can't forget about the hard charging cold front coming out of the northern Plains, as it's raining pretty hard across parts of North Dakota this morning, and this is spreading into northern Minnesota. As the front itself charges southeastward tonight and tomorrow, more strong to locally severe thunderstorms will erupt in Kansas and Oklahoma, thunderstorms that will also contain heavy rains. Once formed, the thunderstorms will likely advance into parts of North Texas, Arkansas and southern Missouri.
While this front will have no trouble gliding off the New England and mid-Atlantic coast Friday night, it will stall in the South, leaving the region warm and humid, a perfect incubating ground for some thunderstorms. With that same feature coming out of the Ozarks on Friday, it will lead to more showers and thunderstorms across of the South to end the workweek.
Even as that is taking place, yet another disturbance will come through the Northwest tomorrow. Initially, it won't have a lot of active weather with it, but as it comes over the northern Rockies Friday, low pressure will redevelop over the Dakotas, and that will help ignite more showers and thunderstorms across the northern Plains Friday night into Saturday, and some of these could well be severe as the march into Minnesota.
And that's just getting into the start of the weekend! The atmosphere as a rule right now is just not warm enough aloft to handle all of the low-level moisture that is now in place over such a widespread area. It's as if the low levels now fully realize it's summer, but the upper level still thinks it's the middle of spring. It's a combination that means there is still no shortage of active weather around the country.
One storm is finally exiting the Northeast this afternoon, only to be replaced by another, slow-moving for the middle and latter stages of next week.
As the pattern becomes more amplified this weekend and early next week, look for it to warm up from the interior west toward the Plains, while it trends cooler east of the Mississippi.
A storm in Indiana will produce heavy rain in the mid-Atlantic into New England over the next 48 hours, but most of the rest of the nation will have little active weather into the weekend.
A powerful storm in Illinois is being blocked from a rapid advance to the East, resulting in heavy rains ahead of it, but also little cooling for the mid-Atlantic and Northeast behind it.
A strengthening storm in the eastern Plains will generate a lot of severe weather and heavy rain through Wednesday all the way to the Eastern Seaboard.
A storm developing over the southern plains late Sunday and Sunday night will help generate severe thunderstorms and flooding downpours from the Eastern Plains to the Eastern Seaboard through Wednesday.