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Karen Continues to Weaken-Hurricane Watches Discontinued

4 Oct 2013, 4:40 pm

Afternoon of October 4th, 2013

* Tropical Storm Karen continues to weaken, sustained winds of 50 mph with surface pressure holding steady. As we mentioned yesterday, wind shear is taking a toll on the storm, persistent (dry) west/southwest winds aloft pushing the convection/storms east of the storm’s center.* Storm still pushing northwest, Tropical Storm Warnings have been extended westward to Morgan City, Louisiana.

* Double-landfall still possible, with tropical storm conditions over the Mississippi Delta (and possibly New Orleans) early Sunday, followed by a second landfall between Mobile and Panama City late Sunday. An eastbound cool front will nudge Karen to the northeast, but the timing of this turn is still very much up in the air, and that will determine the final track late in the weekend.

* Some strengthening is still possible as Karen gets pulled northeastward, but odds favor landfall sometime Sunday as a modest tropical storm.

* It’s premature to let our collective guard down with this system. A storm surge of 1-3 feet is still likely, with some 3-6″ rains inland capable of street and stream flooding.

* Latest HWRF model run suggests a hard right (east) turn for Karen, with possible landfall north of Tampa. This solution is unlikely, but not impossible.

* Hurricane Watch discontinued.  Click Here for the latest watches and warnings from NOAA NHC:

Latest Position. As of 4 PM ET Tropical Storm Karen was located 235 miles south/southwest of the mouth of the Mississippi, still tracking toward the north/northwest at 9 mph.

Lingering Uncertainty Over Final Track. With landfall potentially 36-48 hours away there is still an unusual amount of uncertainty over the final track, as Karen interacts with a larger-scale synoptic pattern that will nudge the storm to the north, then northeast. It’s the timing of that nudge that’s critical. Right now the greatest impacts from heavy rain are most likely over southeastern Louisiana (including New Orleans), coastal Mississippi and Alabama and the Florida Panhandle, but the risk of significant storm surge-related damage has lessened somewhat.

 

 

Consensus Track. Here is the most likely path; T.S. Karen pushing a 2-4 foot storm surge into Chandeleur Sound, east of New Orleans, high enough for minor to moderate flooding at high tide around midnight Saturday night. The storm will weaken rapidly as it pushes inland Sunday night, fueling heavy showers and T-storms from Georgia into the Carolinas, where flash flooding can’t be ruled out.

Tropical Storm Force. The odds of Karen regenerating and intensifying to hurricane force are small, less than 1 in 4. Most models show Karen reaching coastal Louisiana and the Florida Panhandle as a modest tropical storm, with rapid weakening 60 hours from now.

 

Lowered Storm Surge Risk. Steady, sustained (tropical storm force) winds will still create a storm surge, a dome of water amplified by underwater terrain features, reaching a height of 2-4 feet from near New Orleans to Gulfport and Biloxi, about 1-3 feet in Mobile Bay.

 

Panhandle Surge. Right now models show a 1-2 foot surge for much of coastal Florida north of Ocala. The only caveat: if the HWRF verifies and the soggy dregs of Karen drift more east than northeast, then Tampa/Clearwater could see a 1-3 foot surge. Right now the odds of that happening are small.

 

Waveland, Mississippi Peak Surge. Right now NOAA models are predicting a storm surge roughly 2.5 feet above mean sea level around midnight Saturday night, coinciding with high tide. This is down from a prediction of 3 feet earlier today.

 

Inland Flood Potential. With recent heavy rains topsoil across much of the Southeast is saturated, so it won’t take much rain to create runoff issues and flash flooding. Some 2-5″ rainfall amounts are expected as Karen pushes ashore, the greatest potential for street/stream flooding from New Orleans and Mobile to Pensacola and Panama City. As Karen accelerates to the northeast leftover moisture will spike thunderstorms ahead of a cool front, increasing the potential for flash flooding from near Atlanta and Augusta to Asheville and Charlotte.

Summary: Tropical Storm Karen is looking very unimpressive at this hour, and odds favor a late weekend landfall along the Gulf Coast as a modest tropical storm capable of minor coastal damage and inland flooding. There’s at least a 1 in 3 chance of strengthening immediately before landfall, and I think it best to continue to err on the side of caution and preparation. This storm may wind up being more of a sloppy inconvenience than a full-fledged disaster, but a healthy state of paranoia is still appropriate (with any tropical system).

Paul Douglas/Senior Meteorologist- Alerts Broadcaster

Alerts Broadcaster provides severe weather and natural hazard intelligence to businesses worldwide through Alerts, Briefings, and Business Continuity Consultation.  Alerts Broadcaster meteorologists are working  24×7  to provide analysis and perspective that is crucial to your company’s severe weather response. Contact us to learn how Alerts Broadcaster can help protect your organization, staff and patrons: http://www.alertsbroadcaster.com/contact/

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