Thursday, 11:50 a.m.
Even though the system on the Plains is hardly a potent one in terms of the depth or intensity of the surface low pressure found on the current weather map, there has been a lot of active weather with it, including flooding downpours, heavy rain and some severe weather. In fact, we barely have a 1000mb low on the map in Missouri, according to the latest mesoanalysis:
Nevertheless, there's been a lot of rain in Texas, Louisiana, Arkansas and Missouri into Illinois, and we're far from done with the rain. There's also been some severe weather over the past 24 hours:
Severe weather risks this afternoon and tonight run from the western and central Gulf Coast all the way to the Ohio Valley:
As we go into the day tomorrow, the threat of severe weather will fade as the front charges over the Appalachians and the upper-level support tracks northeastward quickly into Quebec and away from the source region for the thunderstorms. There will still be some rain and thunder, but the severity will be lacking, and the intensity of the rain will also diminish.
As one storm fades, another will approach the Northwest. Here's the 12z Oct. 31 NAM surface forecast for Saturday morning:
This storm will move through Washington and Oregon fairly quickly on Saturday, but as it rolls inland, it will generate quite a bit of rain and some powerful winds that may gusty over 50 mph for a time. While that may not seem too bad of a storm, it will actually be the first salvo fired for the development of a more potent storm downstream next week, one that has similar characteristics to the one now moving across the Plains toward the Midwest and Great Lakes.
Between these two systems, the weather will be rather benign. High pressure will build into the Rockies tomorrow night and out onto the Plains to foster plenty of sunshine. While the air mass initially will be cool, it will moderate over the weekend as the high exits and the new trough begins to dig into the West later this weekend.
Behind a weaker, moisture-starved trough exiting the Northeast on Sunday, another surface high will build across the northern Great Lakes toward New England. That will set up a cold night Sunday night across the Northeast, and temperatures will be slow to recover early next week until the high gets off the coast. Once the new storm gets better reorganized on the Plains by Tuesday, though, a strong southerly flow of air from the Gulf of Mexico will once again send warm and increasingly moist air charging northward into the southern and eastern Plains and Mississippi Valley. That will set the stage for another moist system with some severe weather during the middle of next week.
Blocking over the Atlantic and in Europe is buckling the jet stream over the central and eastern U.S. to extend the cool and wet weather the rest of the week and into the weekend.
More excessive wetness is in store from the mid-Mississippi Valley to the mid-Atlantic states, while the brutal heat continues in the West and especially the Northwest this week.
A cool season storm will bring flooding rains and very cool air to the Ohio Valley and Northeast tomorrow into the weekend, while the Northwest has record-setting heat with sunshine.
As the jet stream undergoes amplification late this week into the weekend, it will lead to extremes of heat in the Northwest and cool and wet weather in the Ohio Valley, mid-Atlantic and parts of New England.
Heat and humidity surging across the Mississippi Valley will spark severe thunderstorms in the next 24 hours. The pattern will remain wet from the northern Plains to the East Coast for a while.