Another Friday, another tornado-spewing storm system.  I thought we’d outgrown that cycle, but I should have known better:  May is actually the peak tornado month nationwide, with an average May day generating more than five tornadoes.  As many as 20 were reported yesterday in the Plains states, and here in the mid-South we’re bracing for a hit this afternoon. 

This system is forecast to move into the Gulf during Saturday, and the models look great for fallouts– especially in the TX/LA coastal corridor, which should be seeing rain by early tomorrow morning.  Over the course of the day, winds aloft will gradually shift toward the westerly, steering migrants toward MS/AL for possible late fallouts there (with storms expected to peak mid-afternoon).  Trans-Gulf travelers will have nice tailwinds for most of their trip tonight, so the question is whether they’ll arrive soon enough to beat the front.

They sure have been moving over the last couple of days.  Arrivals yesterday were extremely heavy, especially on the Upper Texas Coast, as you can see from the animation below.  At their early-afternoon peak, when reflectivities reached 30 dBZ, the number of birds passing within range of the Houston beam must have easily numbered in the millions.  Riding a stiff tailwind, birds coming ashore in Louisiana can be seen burning past the coast and arriving in north MS by the end of the day.

Last night, with 925 mb winds reaching a gale-force 40 knots over parts of the South, the pace of nocturnal migration was breakneck.  Birds taking off from coastal forests whizzed completely through Mississippi in a matter of a few hours.  Here’s last night’s animation:

The beginning of May is bittersweet, since it represents the turning of the corner for spring migration, which will be slowing to a trickle in a few short weeks.  But for now, it’s still going full-bore.  Even in the noontime heat yesterday, when I finally got around to stepping outside, the woods were dripping with birds (mostly Tennessee, Chestnut-sided, and Yellow Warblers and American Redstarts; a Swainson’s Thrush, a Warbling Vireo, and a flock of Indigo Buntings were also hanging around). 

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