Hook Echoes, a Strong Texas Tornado, and Softball-Sized Hail

April 26, 2015
2:34 pm


SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
436 PM CDT SUN APR 26 2015
TXC143-262200-
/O.CON.KFWD.TO.W.0007.000000T0000Z-150426T2200Z/
ERATH TX-
436 PM CDT SUN APR 26 2015

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 500 PM CDT FOR SOUTHERN
ERATH COUNTY...

AT 436 PM CDT...A LARGE TORNADO WAS LOCATED JUST SOUTH OF
DUBLIN...MOVING EAST AT 25 MPH.

THIS IS A PARTICULARLY DANGEROUS SITUATION.

HAZARD...DAMAGING TORNADO.

SOURCE...RADAR INDICATED ROTATION.

IMPACT...YOU ARE IN A LIFE THREATENING SITUATION. FLYING DEBRIS MAY
BE DEADLY TO THOSE CAUGHT WITHOUT SHELTER. MOBILE HOMES
WILL BE DESTROYED. CONSIDERABLE DAMAGE TO
HOMES...BUSINESSES AND VEHICLES IS LIKELY AND COMPLETE
DESTRUCTION IS POSSIBLE.

THIS TORNADIC THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF
SOUTHERN ERATH COUNTY.

TORNADO...RADAR INDICATED
TORNADO DAMAGE THREAT...CONSIDERABLE
HAIL...4.25IN

_________________________________________________________________

The Earth has a lot of intense storm activity. Category five hurricanes can inundate cities and turn buildings to rubble. Lightning heats of the surrounding air to five times the surface of the sun, and creates a shockwave that can be heard for miles. Hailstones can weigh up to one kilogram, and cause billions of dollars of damage within less than an hour. But none of these can hold a candle to a category five tornado. Strong tornadoes are, without a doubt, the most terrifying and violent meteorological phenomena on a planet. Nothing else even comes close.

The U.S. doesn’t get the strongest hurricanes (Philippines), the most lightning (Democratic Republic of the Congo), or the largest hailstones (Bangladesh), but we do get the most/strongest tornadoes. We get nearly all of our tornadoes east of the Rockies, but the majority of them occur in the Great Plains. In fact, so many of them occur there that the region has been given a name that has become ubiquitous throughout American culture. Tornado Alley.

I’ve been wondering when we’d see our next big tornado. Springtime is tornado time over Tornado Alley, but I just haven’t seen that many tornado warnings popping up on the National Weather Service homepage this spring. I saw one today though, and when I took a look at the radar, I knew that this was not just some run-of-the-mill tornado. This was a damaging tornado, associated with an intense, supercell thunderstorm.

Fort Worth WSR-88D (Weather Service Radar 88D) image showing a strong tornadic supercell with a clear hook echo NE of Brownwood at 3:53 CDT. Retrieved from the Dallas/Fort Worth NWS Forecast Office.

I attached the picture above so that you could have a clear look at the actual radar imagery of the storm, but here’s a picture below with the counties and warning zones highlighted. Yellow zones are severe thunderstorm warnings (hail of one inch in diameter or greater and wind speeds of 58 mph or greater), and red zones are tornado warnings.

Fort Worth WSR-88D (Weather Service Radar 88D) image showing a strong tornadic supercell with a clear hook echo NE of Brownwood at 3:53 CDT with counties and warning zones included. Retrieved from the Dallas/Fort Worth NWS Forecast Office.

So, how did I know that this storm was likely going to have a strong, damaging tornado? I knew so because the storm had a very clear hook echo.

Retrieved from NWS Storm Spotter Training

For a thunderstorm to be classified as a supercell, it can’t just be massive, it has to rotate. Very few thunderstorms become supercell thunderstorms. The hook echo shown is produced by rain, hail, and in the case of a tornado, debris being wrapped around the supercell due to this rotation. One of the best examples of a hook echo was that of the 1999 F5 Bridge Creek-Moore Tornado, which was among the strongest every recorded. As you can see, the tornado was located right at the hook echo. Oh yeah, this storm produced the strongest winds ever measured on Earth at 301 mph. So yes, hook echoes aren’t there just for show.

Retrieved from Wikipedia page on hook echoes

Thankfully, this storm that is currently going through will avoid the Dallas-Fort Worth metropolitan area, because if they were to receive 4.25 inch hail and a ‘large, damaging’ tornado, there could be over a billion dollars of damage and significant loss of life.

The latest update (530 PM CDT) says that although the tornado has ended, there is still 3-inch hail and 70 mph gusts with this storm. This is a very, very dangerous storm folks. If you want a tornado, you’ll have to head down to Houston/Galveston. I’m not as worried about this one though, because the storm doesn’t have a significant hook echo.

Houston WSR-88D (Weather Service Radar 88D) image showing a tornadic supercell headed ENE at 5:26 CDT with counties and warning zones included. Retrieved from the Houston NWS Forecast Office

Back here, there is a weak band of showers over the Olympics right now, so be prepared for the elements if you go outside tonight… you might get a tad wet. Don’t forget to bring a towel!

UPDATE 8:00 PDT (10:00 CDT)

Look some of the latest pictures from the Dallas-Fort Worth scanner Twitter page. The below softball-sized hailstone was from the storm I talked above.

Photo credit: Zoey Rae James. Retrieved from Dallas-Fort Worth Scanner Twitter Page.

Also, they are now getting more tornadoes. The pictures below were also taken from their Twitter page. I bet you know where the tornado is! It looks like they do.

Radar showing hook echo, 9:39 pm CDT. Retrieved from Dallas-Fort Worth Scanner Twitter Page.

Radar showing hook echo, 9:45 pm CDT. Retrieved from Dallas-Fort Worth Scanner Twitter Page.

The National Weather Service is acting like they think this is a particularly strong tornado, perhaps even stronger than the one earlier today. As I said before, a strong hook echo is indicative of a strong tornado, and the hook echo on this storm is stunning.

THE NATIONAL WEATHER SERVICE IN FORT WORTH HAS ISSUED A

* TORNADO WARNING FOR...
NORTHWESTERN HILL COUNTY IN CENTRAL TEXAS...
SOUTHERN JOHNSON COUNTY IN NORTH CENTRAL TEXAS...

* UNTIL 1045 PM CDT

* AT 1010 PM CDT...A CONFIRMED LARGE AND EXTREMELY DANGEROUS TORNADO
WAS LOCATED NEAR CLEBURNE STATE PARK...OR 9 MILES SOUTHWEST OF
CLEBURNE...MOVING EAST AT 20 MPH.

THIS IS A PARTICULARLY DANGEROUS SITUATION.

HAZARD...DAMAGING TORNADO.

SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO.

IMPACT...YOU ARE IN A LIFE THREATENING SITUATION. FLYING DEBRIS
MAY BE DEADLY TO THOSE CAUGHT WITHOUT SHELTER. MOBILE
HOMES WILL BE DESTROYED. CONSIDERABLE DAMAGE TO
HOMES...BUSINESSES AND VEHICLES IS LIKELY AND COMPLETE
DESTRUCTION IS POSSIBLE.

Charlie

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