Tuesday, September 3, 2013

Sct'd T-Storms Each Day This Week

By Jay Grymes & Steve Caparotta

A cool front will continue to sag southward into central Louisiana later today and then stalls over the state. The front likely meanders over and near the Gulf Coast states for the next several days, eventually fizzling out by the weekend. Regardless of where the front is positioned, the WAFB viewing area will remain under the influence of relatively moist-and-unstable Gulf air. 

That means mainly fair but somewhat muggy mornings for metro Baton Rouge, with spotty showers closer to the coast -- much like we’ve seen the past couple of days. Plan on warmer-than-normal and humid afternoons with scattered mainly-afternoon t-showers right into and through the weekend.

Yes, it is September, but summer is far from over yet. 

Don’t be fooled -- September can be a very warm month for the Gulf Coast region. In fact, on average, daytime highs reach the 90⁰s on nearly half of all September days in Baton Rouge. But as we head into the latter half of September, we can often count on that first real feel of autumn -- what some might call the “hallelujah front!” 

Hopefully that first real break in the summer heat is not too far down the road (or calendar, so to speak), but the way the atmosphere is expected to behave over the next seven days or so, that first “welcome to fall” front is certainly not just around the corner.

In the tropics, there are no current threats for the U.S., but the National Hurricane Center (NHC) is watching three areas of interest: (1) an area of disturbed weather near the Yucatan, (2) “Invest 97L” extending from the eastern Caribbean across the Lesser Antilles, and (3) “Invest 98L” located in the far eastern Atlantic. 

The disturbance over the Yucatan has some potential for development in the coming days as it moves westward over the Bay of Campeche, but unless it stalls over the southwestern Gulf, it will likely run out of time before it can “earn a name.” 

Although 97L is currently being held in check by nearby “dry” air, conditions for 97L could become more favorable in the coming days as it moves towards the Greater Antilles (Puerto Rico & Hispaniola). After that, most of the current guidance suggests that 97L may take a more northward turn towards Bermuda. As for 98L, it is simply too far out in the Atlantic to worry about at this time.

As we’ve mentioned many times recently, early-to-mid September is also the “climatological” midpoint of the hurricane season -- statistically, the season peak occurs on or about September 10th. We’ve also noted a number of times about Louisiana’s track record during September: nearly half (about 47%) of all hurricane and tropical storm landfalls since 1900 for the Bayou state have occurred during September. By our count, there have been 17 September hurricane landfalls for Louisiana since 1900, 6 of which were ‘major’ storms. Add to that another two-dozen tropical storms, and you come up with 41 landfalls in 113 seasons.

Consensus among tropical weather experts is that, beginning in the 1995 season, the Atlantic Basin has been experiencing a persistent trend of elevated activity. While we have yet to see a hurricane in the basin this season, we must remain watchful and prepared. Two prime examples are the 2001 and 2002 seasons: neither season saw its first hurricane until September. And how active were those two seasons?

2001 -- 15 ‘named’ storms, 9 hurricanes, 4 ‘majors’

2002 -- 12 ‘named’ storms, 4 hurricanes, 2 ‘majors’ … but maybe more importantly, there were 3 Louisiana landfalls after September 1st: TS Hanna, TS Isidore and Category-1 Lili.

Since the 1995 season (18 seasons total), Louisiana has suffered landfalls on or after September 1st during 8 of those 18 seasons, including multiple hits after August 31st during 2002, 2004, and 2008. Among the more memorable storms in this stretch are 2002’s Lili, 2005’s Rita and 2008’s Gustav and Ike.

Yes, maybe we’ll be lucky this year ... we surely deserve it. But just remember, the season is far from over.

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