Tropical Cyclone of Oklahoma?

[Joshua T. Clark]

To all,

Has there ever been a tropical cyclone that maintained enough of the characteristics of a tropical cyclone per NHC's definition "a warm-core, non-frontal, synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center." pass over Oklahoma.

I know from the 2007 season that the remants of TS Erin traversed the state. What if any possibilites would have to exist for a tropical cyclone making landfall along the TX/LA border (this being the closest to the coast the SE corner of Oklahoma is) for it to maintain as a significant tropical cyclone over Oklahoma.

I suppose due to my knowledge of tropical systems that the only limiting factor for this is the removal of the warm tropical waters as a moisture source. Could other factors like the tropical moisture conveyor belt that commonly bring tropical moisture to the state or a very intense non-tropical synoptic size low that produced large amounts of rainfall with a period of warming that significantly moistens the atmosphere be enough to maintain a tropical cyclone for a significant period of time over land.

There was a prime example of that this season with Tropical Storm Fay maintaining strength and/or strengthening over Southern Florida. I tend to believe that the conditions would have to so extraordinary for this to even occur. I think it would matter that this storm would probally have to be a major hurricane at landfall.

 

[Chris Nuttall]

TS Fay was a little bit different in that the center moved back over water several times. So, technically, I believe there were several landfalls. If I remember correctly, NHC officially classified Erin's brief restrengthening over Oklahoma as just a remnant low. I think it was mainly because the increase in strength was fueled by convective processes rather than the latent heat release from ocean water.

Really, the only thing I believe it would take would be a fast moving system. There's quite of bit of land, and rather rugged terrain that would have to be covered. It really would be a combination of sufficient strength and speed to keep it's tropical characteristics to make it that far inland.

Offhand, I can't think of any specific systems that have done this. If any place would be affected, it would most likely be McCurtain County, which was under a Tropical Storm Wind Warning today.

 

[Matt Sellers]

As Chris mentioned, the NHC classified Erin as a "low" while moving across Oklahoma - the remnant low interacted with a weak shortwave trough. The resulting convective system became, in effect, a weak to moderate tropical storm as it traversed the state from southwest to northeast on the morning of 8.19.7. IMO, Erin was better-organized over Oklahoma than it was over the Texas coast at landfall.... it took interaction with the westerlies and a shortwave to turn the weak tropical storm into a land-based rare case of a MCS with an eye.

From a sensible-weather standpoint, the conditions associated with Erin's remnants in Oklahoma represents the strongest-possible effect for any tropical cyclone or its remnants to affect the state (accounting for strong winds as well as heavy rainfall.)

Even a fast-moving intense hurricane to strike the Texas or Louisiana coast will still have to cross over 200 miles of land to reach the southeast corner of OK, in McCurtain Co. The strongest hurricanes will weaken below that strength around 100-130mi inland (after 7-10 hours over land) with winds weakening below storm-force soon thereafter. Hurricane Rita (2005) affected the southeast corner of Oklahoma with winds to marginal tropical-storm force while its center moved through southwest Arkansas.

Climatology shows that intense hurricanes (cat 3+) moving faster than 20mph are extremely rare, especially within the Gulf of Mexico and moving with a significant westerly component; in a theoretical case of a northwestward-moving major hurricane hitting the upper Texas coast, it would have to move at 25mph or more to reach Oklahoma within 8 hours of landfall. Friction would take its toll on the storm, no matter how moist the landmass around it. While areas of Oklahoma nearest the center of the weakening storm would experience gusty winds, the main danger would be heavy rainfall.