Tuesday, 11:30 A.M.
If you are a long-time reader of my columns, you are well aware of my bent toward warm weather, especially during the winter season. The older I get, the more I like the warmth. It's just plain easier on the body, hands down, and allows me more freedom to get out and play in it without having to take 15 minutes to get properly dressed and undressed to get out and have fun in the weather. So, with the upcoming warmth spreading across the country, you can rest assured that I'll be out enjoying it as best I can, racking up the miles on the bike - and out running in preparation for a June 8 half marathon, something I've never ever considered doing before!
With the warming, though, there are going to be some problems. There will be two opportunities for severe weather in the next week, maybe three. The sure-fire threat is about to unfold in Texas and will expand to include Louisiana in time tomorrow and perhaps encompass parts of Mississippi and Alabama up into the Ohio Valley on Thursday.
Look at the 500mb forecast this afternoon:
That's an impressive upper-level low over northern Mexico, and the upper-level difluence over southeastern Texas this morning has already helped spawn some strong thunderstorms. As the atmosphere gets warmer in the low levels this afternoon and tonight, the moisture gets deeper from off the Gulf of Mexico and the upper level low rolls into and across the state tonight and tomorrow into tomorrow night, the atmosphere will become increasingly unstable, and that will result in widespread rain and strong thunderstorms, some of which will become severe. Here's what that setup looks like:
As concerned as we are about severe weather, I think flooding is the bigger issue when push comes to shove, as a large area will see several inches of rain from this slow-moving storm. Here's the latest projected precipitation totals from 7 a.m. today through 7 p.m. Eastern Time Thursday:
That's the latest NAM forecast. The GFS has that heavier rain threat farther south and east with time:
My gut tells me the GFS is going to be closer to reality when push comes to shove, as the heavy rain axis over time ought to be focused on where the strongest push of tropical moisture will end up being, and that should be over East/Southeast Texas into Louisiana. That said, areas up into Arkansas and western Tennessee will likely see 2 to 3 inches of rain, with at least twice that in parts of East/Southeast Texas into Louisiana.
That's round one. Round two will develop this weekend as the front separating all of this springlike warmth from a building arctic air mass becomes the focal point for more rain and heavy thunderstorms. This is the latest GFS forecast for Saturday night:
The European model looks fairly similar, for what it's worth. The bottom line is that as a feature rolls through the Northwest and down the western side of a deepening upper-level trough into the Southwest late this week, it will eventually be spit out the other side of the trough on Saturday. That's when a new round of strong to potentially severe thunderstorms with hard, flooding downpours can erupt. The risk zone will develop from Southeast Texas all the way to the Ohio Valley Saturday late and Saturday night into Sunday.
And it wouldn't shock me if there was at least one more outbreak of heavy rain and strong to potentially severe thunderstorms early next week as this front just inches along toward a massive upper-level ridge off the Southeast coast. Any wave could focus the warm, moist air over the Gulf of Mexico and the Deep South toward that frontal boundary, where the contrast may be quite sharp.
A building upper-level ridge of high pressure in the West will promote hot, dry weather in the Northwest, while a downstream trough brings cooling through the Midwest into the Great Lakes and Ohio Valley.
A pattern more typical of late July and early August is shaping up around the country, one with heat and humidity, but with fewer incidents of severe thunderstorms and flooding.
There will be plenty of heat and humidity from the southern Plains to the East Coast this week while much cooler air prevails for a time over the Northwest to the northern Plains.
Severe thunderstorms raked across the Midwest and Ohio Valley in the past 24 hours, with more on the way this afternoon. The pattern will repeat itself over the next week.