Friday, 11:30 a.m.
Since last week, most of the nation has been devoid of storminess. We've clearly had a clean break from the previous week, where three storms in succession made much of the country fully aware of winter and the power of storminess. This week, not a lot more than crickets for MOST of the country.
That said, there has still been a lot of moisture in the subtropical branch of the jet stream. It did rain - a lot - earlier this week from southeastern Texas into Louisiana and Mississippi, even into portions of Alabama, Georgia and the Carolinas. Now, was that really a stormy situation? No, as the lowest pressure I could find going back at looking at the weather maps was about 1011mb. That's not exactly the kind of system that makes me think of a stormy weather pattern! No, it's been much more a product of a wide band of moisture being summoned from the eastern Pacific up across Mexico into southern and eastern Texas and the western Gulf of Mexico.
Within this broad band of moisture, there has been a series of weak disturbances. As each one comes along, it generates thicker clouds and bands of precipitation. Earlier in the week, you had a stronger one that was able to concentrate the rain along the western Gulf Coast and southeastern Texas into Louisiana and Mississippi, resulting in as much as 4 inches of rain in Galveston. Associated with that particular disturbance was a better contrast between either side of a front - it was warm (temperatures in the 70s) and humid (dew points in the 60s) along the Gulf Coast, while it was much colder on the other side of the boundary. Since then, that contrast has been squeezed into central and South Florida, with northern Florida and the entire Deep South just plain chilly. Thus, rain amounts with more feeble disturbances have been much lighter and more spotty, despite there being a lot of clouds around.
The system that dumped as much as 8 inches of snow on parts of Texas from the mountains around El Paso to the high ground of the Big Bed area of the state is an entirely separate feature. Here's the NAM forecast depiction of it early this afternoon:
Over the next 24 hours, the moisture associated with this upper-level low will be stretched and ultimately split into two pieces, with some of it heading across the Mississippi Valley into the Ohio Valley and lower Great Lakes, with the rest closer to the Gulf Coast and over the Gulf of Mexico:
Since the frontal boundary is pretty far off the Gulf coast, the best upward motion and overrunning will likely end up along or off the Gulf Coast late tonight and tomorrow into tomorrow night, which means the steadiest and heaviest rain will also be near or even off the Gulf coast.
This relatively quiet weather pattern won't last for long. The next feature will dig into the West this weekend, and by Sunday evening, will be aiming at the Southwest:
There are distinct differences among all of the various computer forecasts as to how fast this storm rolls out of the Southwest. I'm not going to discuss that issue today. I'll save that for Monday when the timing differences should be much, much smaller. Instead, I'll look at the big picture. Off the Southeast coast, stretching from the southeastern Gulf of Mexico through South Florida into the southwestern Atlantic and the northern Caribbean, there will be a strong upper-level ridge deep into next week, if not beyond.
At the same time, there will be a strong upper-level low near the northwest shores of Hudson Bay - essentially, the polar vortex. Stretching from that low southward into the Rockies and West, we'll find a pretty deep and deepening upper-level trough later next, one that is likely to have still another strong feature roll into the Southwest late next week. Here's how that might look next Thursday evening:
This should set the stage for a continuation of an active weather pattern into and beyond the midmonth period. With that latter storm, expect much colder air to be drained into the West and Rockies late next week and next weekend, increasing the contrast between it and a warm, moist air mass over the Gulf and Southeast. Pretty much all of the models, despite their various timing issues, agree on this much.
The record warmth of recent days will be replaced by a much colder air mass following a cold front moving from the Ohio Valley to the East. Rain will change to snow in the higher ground of upstate New York and northern New England.
Nicole crossed Bermuda Thursday morning as a major hurricane. Two storms will blast the Northwest with high winds and heavy rains in the next 72 hours, forcing warmer air out into the nation's midsection.
Matthew is a dangerous hurricane bearing down on the east coast of Florida. While it ravages Florida and parts of the Southeast into the weekend, it will spare the Northeast of its fury.
Major Hurricane Matthew is now a significant threat to the entire Eastern Seaboard Thursday through the weekend with with potentially destructive winds and excessive rains.
Heavy rain will soak drought-stricken areas of the mid-Atlantic over the next couple of days. Focus will then shift to Matthew and its potential to impact the Eastern Seaboard with more heavy rain later next week.
Summer has ended astronomically, but from a meteorological standpoint, there's plenty more warm weather heading into October from the Plains to the East.