Wednesday, October 2, 2013

Who is Karen and why should Mid-Southerners care?

So far, the forecasted "active" 2013 tropical season has been a dud with only one storm (Andrea) having much of any effect on the U.S. mainland and most storms that form struggling to survive. Only two storms have managed to attain hurricane status, one of which stayed far out to sea (Humberto) and one which soaked an already flooded eastern Mexico (Ingrid). Though potential causes are surmised (dry air over the Atlantic/Caribbean being one), that is a blog for another day.

A summary of tropical tracks for 2013. The Atlantic and eastern Pacific have both been relatively quiet, particularly in regards to Atlantic land-falling storms. Courtesy HamWeather.
As we enter the last quarter of the Atlantic tropical season, all eyes are turning towards the southern Gulf of Mexico and 97L - a tropical disturbance that is predicted to have a "high chance" of formation into a tropical depression or storm.  Most potential forecast tracks take it north through the Gulf and towards the central Gulf coast - or roughly from Louisiana to the Florida Panhandle.  If the disturbance does manage to form into a named storm, which requires 39 mph sustained wind, it will be called Karen. 

So why should Mid-Southerners care?

For one, if you have school children in Shelby County public schools, a week-long Fall Break starts after the bells ring Friday and I know many of you will head to the MS/AL/FL Gulf Coast to shake off the first quarter of the school year and enjoy early fall on the beach. My family has done that a couple of times - it's an awesome time of year to be on the coast! So if you're headed south this weekend, take heed. As model solutions will show below, the most likely time for adverse weather on the coast will be Saturday, with some remnants into Sunday (if projections have any semblance to reality). Hopefully your entire trip won't be ruined. If a Saturday landfall looks to be the case, my suggestion would be to consider a short delay in your travel plans if you are flexible, perhaps going down on Sunday.

Secondly, those who are in town likely have outdoor plans for the first weekend in October, not the least of which might be the Memphis Tigers football game Saturday afternoon vs. Central Florida. A cold front is expected to move through Saturday bringing a high likelihood of rain and also some thunderstorms. The front will be a potent one with warm and humid air (temps well into the 80s and dewpoints up near 70 the next couple of days), colliding with an airmass from Canada that will drop temps into the lower half of the 70s for highs and possibly some 40s for overnight lows early next week! If "potential Karen" hooks up with this cold front, rainfall amounts could be enhanced.

The Mid-South forecast

The local forecast, though, is tricky for several reasons. First, computer data is having a hard time agreeing on the timing of cold frontal passage, which will directly correlate to when it rains on Saturday, whether storms develop, and how strong they might be. In addition, tropical disturbances that have not actually become full-blown tropical systems yet tend to have highly variable forecasts. Some examples of the possible forecasts are below.

If Karen forms and makes a run at the Gulf Coast (which we think she will), her moisture could get absorbed into the frontal system and rain amounts could go up very quickly in our part of the world, especially if that happens on Saturday. If it happens Saturday night, the front could slow down and we could see lingering rain on Sunday morning. None of this is for certain yet but it's worth monitoring.

Tailgating on Saturday could be affected by rain. Lightning delays can't be ruled out at the Liberty Bowl.  Always heed precautions announced at the stadium and seek adequate shelter if in a weather delay.

The Gulf Coast forecast

What also isn't certain, for those of you bound for the Gulf Coast, is where "Karen" may head and how strong she may be. Unfortunately, there may not be a lot of notice on the ultimate destination and strength of this storm until decisions on trips have to be made - perhaps less than 48 hours from landfall.  My best guess at this point is that anyone planning to be from New Orleans to Panama City (including Gulf Shores/Destin) needs to keep a close eye on the situation. A hurricane is NOT expected at this time, but a strong tropical storm with wind of 50-60 mph and torrential rain can't be ruled out along the central Gulf Coast. Our MWN Tropical Page will have the latest.

These are "potential" tracks for the disturbance and should not be taken as a forecast. They all point to the possibility of a Gulf Coast landfall though.  The timeframe for landfall according to these models is mid-day Saturday to mid-day Sunday. It should be noted that a couple of well-respected models do not bring the disturbance to tropical storm strength.
The forecast storm intensity of the models shown above. Nearly all peak the disturbance in the tropical storm range of 35-60 kts (40-70 mph) prior to landfall.

Like a Boy Scout, be prepared

We encourage you to check out the StormWatch+ feature in our MWN mobile apps, which has been upgraded and now includes StormWatch+ EnRoute, which will warn you if you are traveling and drive into severe weather, as well as the addition of tropical weather alerts! Download the app now if you haven't already, then upgrade in-app to add StormWatch+, which alerts you to severe weather anywhere in the nation, not just in Memphis. Links to the download page are below. We'll also keep you posted the next few days on our social media channels. Stay tuned!

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