Wednesday, December 26, 2012

Christmas Day 2012 Tornado Outbreak Will Go Down in the Record Books...

As feared, an extensive tornado and severe thunderstorm outbreak took place yesterday on Christmas Day.

So far, a total of 25 tornadoes have been reported across the South on Christmas Day:  6 in Alabama, 2 in Louisiana, 13 in Mississippi and 4 in extreme southeast Texas (as indicated by the red squares on the image below - click to enlarge):

Since reliable records have been kept (in 1950), this is the first time that a tornado has taken place on Christmas Day in the states of Mississippi and Alabama.

The final number of tornadoes will change (up or down) as ground-truth storm surveys are currently being conducted by the National Weather Service (NWS) across the affected areas.  (Look for individual "Tornado Chronicles" posts here on the blog for information on specific tornado events as information becomes available.  One such post has already been created for the tornado that struck Mobile, AL yesterday evening).

The image below shows radar indicated rotation swaths for a 2 hour period ending at about 3pm CST yesterday afternoon.  This should give you an idea as to the number of potential tornado tracks that are out there.  Keep in  mind that this image did not yet reflect the developments across southeastern Mississippi and southern Alabama:

Fortunately, the tally of serious injuries and deaths from the event has been remarkably low so far, hopefully a result of folks paying attention to the weather after having been warned about what was expected to unfold for several days in advance.  

The NWS issued a total of 264 different severe weather warnings during the event, which is a healthy count on any day, much less Christmas Day.  This total included 92 different tornado warnings, as shown in red on the map below:

The NWS's Storm Prediction Center (SPC) was also very busy yesterday.  They issued a rarely used "Particularly Dangerous Situation" or "PDS" Tornado Watch for an area from southeast Louisiana across central and southern Mississippi and into southwestern Alabama:

As you can see at the bottom of the image, the PDS Tornado Watch was valid from 12:55 until 8:00 pm CST, and covered the majority of the more vigorous tornado activity was was reported on the ground and indicated by radar, including the tornado that struck the Mobile, AL area.  This was the 2nd time in less than a week that Mobile, AL took a direct hit by a tornado (the 1st tornado was just 5 days earlier, on December 20th!)

So far, I have not been able to find another occurrence where a PDS Tornado Watch had ever been issued before on a Christmas Day.  I have also not found another instance where such a watch had been issued in the month of December, but I'm not quite finished with that research just yet.  In any case, it was an extremely rare event for any day in December, much less for Christmas Day!

I have created the following posts on the more notable individual tornado events from Christmas Day 2012:

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