Tornado Dynamics AL/MS/GA/FL 2/17/08

ONTARIO WEATHER SERVICE
TORNADO DYNAMICS LABS
FEBRUARY 17, 2008 - 4:00am PST

Source: [link to ontarioweatherservice.com]

Linear Or Tornadic? Florida is in tornado dynamics in parts as well.

Late morning - Early Afternoon 2/17/08 ( 6 hour warning time )

TORNADO WATCH: An on-going line of severe thunderstorms that hit Eastern Texas yesterday will still provide the need rotation in and ahead of it for tornado chances. Although the line is mainly linear, this morning rotation within it has prompted NWS to issue some tornado warnings for Mississippi. Am thinking to go with a tornado watch because of the shear dynamics within the line itself. Anything out ahead of it, mainly Southern Alabama Panhandle will have the chance to rotate, however the magnitude of rotation may be on the weak side. A lot of the tornado dynamics are staying with this line of severe thunderstorms. The tornado watch box extends from Southeastern Louisiana to Central Alabama. Feel that temperature factor and instability lacking in Northern Alabama will keep tornado chances down in that area so no threat is imminent during this window. Storms will be moving to the North-Northeast.

[link to ontarioweatherservice.com]
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Later Afternoon - Early Evening 2/17/08 ( 8 hour warning time )

TORNADO WATCH: As the day wears on, heating will cause the instability to spread a bit further North into Alabama. I do feel a watch is needed for this because of the dynamics within the main line of thunderstorms that should be crossing this area. Lift indications out ahead of it indicate the chance of isolated supercells just ahead of the line. If this happens, it would be in Southeastern Alabama. The rotation chances are in a level 1 and 2, however a tornado cannot be ruled out.
The activity will be across the Western Florida Panhandle as well. Some lift out ahead of the line, probably convergence off the coast could develop a supercell ahead of the line. Could even be a line of storms oriented West to East which would move toward the coast West of Panama City over time. Will need to think about this if living there. You are included in this watch. Storms here would have a pretty good inflow chance with the Southerly wind. Beach activities should be thought about when developing cumulus are seen off this coast.

TORNADO WATCH: Took me a while to debate on a watch or advisory for Southeastern Florida. I am going on a limb because SPC/NOAA does not even have this area under a 2% tornado at the time I write this so here we go. Level 3 tornado dynamics are indicated with a lifting source, low level convergence in this area. This means that thunderstorms with rotation in them can form in this. A have therefore went ahead with a tornado watch box. This is not near the linear line in Alabama so plenty of heating for this to happen.

[link to ontarioweatherservice.com]

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Early Evening - Sunset - Just After Sunset 2/17/08 ( 12 hour warning time )

TORNADO WATCH: Because of the insane shear still within this linear line of storms, have put a tornado watch across Western Georgia, including the Atlanta area. Likly hood of just a thunderstorm line going through is high, however with the shear in place, cannot rule out some spinups along it. This extends down through Eastern Alabama. Subsidence behind the front should allow for parts of the Southeastern Alabama area to clear out during this time frame, however the AL/FL border and down to the Panhandle will still have activity.
I do feel that although level 5 dynamics will be over the SC/NC border, instability will lack and no real threat is seen. Watch will not extend to level 5 up there.

TORNADO WATCH: For the Southeastern Florida area. Dynamics from the first watch will be carried over to the North along these areas. West Palm Beach is in this watch. Thunderstorms moving North-Northeast may cross into the ocean between Jupiter Park, and Vero Beach. It is possible that any storm in here could rotate or produce a tornado. While chances are just chance, know dynamics are in the area whatever happens. This is a very small watch box, and may demonstrate the map usage if something occurs.

TORNADO ADVISORY: A variation of the watch box, this advisory is for a weak rotation chance. At OWS we don't take chances we double up on everything. If rotation is possible we issue. Flat out. This box may or may not produce a tornado, but any tornado should not be strong. The advisory extends from Punta Gorda, Northeast to about Lake Wales, FL. The convection forming in this area would move North-Northeast to just South of the Kissimmee / St. Cloud areas. This is an advisory and not a watch. Treat it like a watch if you wish however an advisory is when rotation in storms is possible.

[link to ontarioweatherservice.com]

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Well After Sunset - later night but not after midnight. 2/17/08 ( 14-18 hour warning time )

TORNADO WATCH: A tornado watch remains for the highly sheared linear line that would continue across Georgia. Going to keep this watch going, however must stress mainly thunderstorm lines like what is advertised on the map mean just severe wind possible. Do not think a chance of a tornado in this line is not possible because it is. This line would extend from about Northeastern Georgia at a weaker point, through Central, then Southwestern Georgia, before entering the very end of Southeastern Alabama, and into the Central Florida Panhandle where Panama City is, before going out into the gulf. Possible that a blockage in this front, and subsidence will make a space in the storms about 50-100 miles South of Panama City, FL. This isn't anything serious just thought I'd say it. Tornadoes are possible within this line. At this time, a cap across Southeastern George coastal will make storms unable to get off there. May have to wait for the line over the night yeah?

TORNADO ADVISORY: Tornado dynamics will be rather weak, but still enough to warrant the advisory we issue. Southeastern Florida about East and North of the Okeechobee area may have the chance of a tornado or rotation in any storms forming in the area. Convergence from the East and South suggest storm activity in this area, moving due North from there. Weak dynamics, but anything can happen in this small box. Suggesting storms offshore will not need to be worried about as I did include them for your viewing. They should be well offshore to hurt land.

TORNADO ADVISORY: Debated to put this area under an advisory or not. As small as an area as it is, the chance of initiation may happen ahead of the frontal zone here. Now level 1-2 tornado dynamics aren't that bad, however rotation is still possible in this. This is from about Palatka North-Northeast to Green COve Springs. Again, weak, but possible. Storm movement would be North-Northeast.

[link to ontarioweatherservice.com]

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Kevin