Were Thursday's storms in Houston a #derecho?

There's no doubt the storm complex was extremely destructive, long-lived and part of a larger MCS, or mesoscale convective system, that traveled a considerable distance.

BUT some semantics we need to get into. A thread: For starters, as @WeatherProf and @capitalweather adroitly point out, these MCSs formed on the northern periphery of a sprawling heat dome over Central America and the Gulf. That's a classic recipe for progressive derechos to ride along the CAPE gradient as "ridge runners."

As one reviews radar data, it becomes increasingly apparent that a tornado warning should very much have been in effect for Dortches, N.C.

This was, simply, a big miss; we weren't *anticipating* it, but radar/warning *reaction* was slow.

Let's look at the radar: As the storm is over Nashville at 12:15 p.m., it is obviously hooking. It also appears it may be ingesting some streamwise vorticity from a boundary, with can be seen south of Spring Hope. SPC had also had a mesoscale discussion up for 1 hour 35 minutes at this point.

An *incredible* atmospheric river event in #California.

A "double bomb" off Pacific Northwest coast with an air pressure rivaling that of Sandy in 2012 is swirling ashore record moisture.

Up to a foot of rain, debris flows, meters of Sierra Nevada snow. washingtonpost.com/weather/2021/1… In California, Sacramento could see 4 to 6 inches of rain.

They just wrapped up a record dry streak that lasted an incredible 222 days. Flash flood watches blanket the region.

This is feast from famine. Major drought-denting rainfall totals.

Why do we say wait 30 minutes after thunder before venturing outdoors?

Exhibit #4372. Lightning – cloud to ground – 70 miles away from the main precipitation core in Texas with this supercell. The anvil carries charge and occasionally sparks lightning.

Only takes one strike. Also a great example of shear. The storm is moving southeast, but the anvil east-northeast.

That change of wind speed/direction with height is what brewed the rotating updraft to begin with.