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Weather watch



Weather junkies will enjoy a report on tornadoes this year from the Weather Service's John Robinson. 66 so far this year. In case you wondered, the Super Tuesday tornado Feb. 5 is still the longest tracked tornado recorded in Arkansas -- 121.84 miles.


One of the most-asked questions so far this year has been how many tornadoes we have had so far in 2008.

I think most of you know how the official count works, but just in case, here's an explanation:

Each NWS office has two months after a month ends to compile all its severe weather statistics and submit them to the Storm Data publication.  This may seem like an awfully long time, and for some types of events, it is.  However, we want the final record to be as complete as possible.  I get newspaper clippings from virtually all of the newspapers in the state when they write articles about bad weather (floods, tornadoes, winter weather, etc.).  Typically, we get these clippings about three to four weeks after they are published.  Then, one of our forecasters (Amie Browne) and I have to read through them.  If the weather events have occurred in another office's CWA, I mail them the pertinent articles.  When all the floods and tornadoes were going on earlier this year, we got about 1500 clippings in 6 weeks!  Also, when flooding occurs, the extent of the damage can't be known until the water recedes.  As we saw earlier this year, this can sometimes take weeks.

Anyway, each NWS office must have its reports for May compiled and submitted to Storm Data by the end of July.

I have looked through all the reports that are available as of today.  Using these reports, the statewide total for tornadoes so far this year is at least 66.  As I looked through the preliminary reports, I could see that not all the NWS offices that deal with Arkansas have compiled all their reports for May.  That's why I say there have been "at least" 66 tornadoes.  To my knowledge, there were no tornadoes anywhere in Arkansas in June or July.

I am currently typing up a list of all the tornadoes as they will appear in Storm Data.  After all the reports for May have been posted, we will post the list on our Web page.  Thereafter, I will add additional tornado reports as we learn of them from other offices' Local Storm Reports, Public Information Statements, and e-mails.  Please keep in mind that when we have a big outbreak of tornadoes, I am frequently working 11 to 16 hours a day, and I will get the list on the Web updated as soon as I can.

Reports that have been submitted to Storm Data will be in one color font, and preliminary reports that have not been submitted for publication will be in another color font.  One thing to keep in mind:  Even after formal publication, if additional details are found (such as the recent death of the woman from Atkins five months after the tornado) or if errors are discovered, Storm Data entries can still be changed for up to 18 months.  Should this occur, I will update my list on the Web accordingly.

Finally, let me explain a little bit about how storm surveys are now done.  Here, I am speaking specifically about how we at WFO Little Rock do ours, but I'm sure the process is the similar at other WFOs.

We now take a GPS-enabled laptop with us on surveys (other offices may use hand-held GPS units).  As we go along, the lat/lon points are marked at the approximate center point of damage each time we cross the tornado's path.  When we complete the survey, we compile an approximate path and path length while we are still driving and call it back to the office.  This is the quickest way to get the information to you, via our Public Information Statements.

In the succeeding days after the survey, we take our lat/lon points off the laptop and begin entering them into the computer program that is used to compile the entries for Storm Data.  Using the specific points, the program names an exact starting and ending point, as well as path length.  The towns named and the path length may differ slightly from what appeared in the preliminary PNS, but this is the most exact data we have.  Please note that the computer program sometimes picks very small communities (such as Wampoo in southeast Pulaski County) when it outputs the starting and ending points.  Google Earth or similar mapping programs are good sources if you are unfamiliar with the names of the communities.

The State of Arkansas is now much more involved with GIS mapping after tornadoes.  The Arkansas Forestry Commission often maps the paths by air (and notifies out-of-state timber owners if they have damage on their land) and the Arkansas Geographic Information Office (AGIO) may have aerial mapping done as well.  Much of this information is then presented to Governor Mike Beebe.  We at the NWS trade information back and forth with the Forestry Commission and the AGIO.  And, as we always have, we also trade information with the Arkansas Department of Emergency Management. 

Sometimes the state's aerial surveys see things we could not see from the ground.  A recent example was the tornado that struck Stuttgart on May 10th.  We had a starting point shown in Lonoke County and then a continuous path through Stuttgart and then turning off to the southeast in Arkansas County.  When the Forestry Commission flew the path, it turned out that the path was not continuous.  Their mapping showed a short path that began in Lonoke County and then ended in a swamp south of U.S. 165 in Prairie County.  Then, there was a continuous path from near the Prairie/Arkansas County border on through Stuttgart as we had plotted it.  Obviously, on our driving tour of the damage, we could not drive through the swamp, since there are no roads there.  However, using the data from the Forestry Commission, we have redone our maps (and Storm Data entries) to show that the path was not continuous.

Also, when everything was entered into Storm Data, the official path length of the February 5th tornado ended up being 121.84 miles.  This is what is going into the official record.  It is still the longest-tracked tornado ever recorded in Arkansas.

Sorry this ended up being so long.  To sum up, soon after the end of this month, we will post the list of tornadoes so far this year on our Web page.  As additional storms occur after that, the list will be updated as soon as possible to add additional tornadoes.  Again, these initial entries will be preliminary and subject to change as additional information comes in.  In 2009, I will begin a new list from scratch for the new year.

I hope by compiling the information in this manner, it will be easier for all of us to keep up with the latest tornado counts.

John Robinson

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