Sunday, May 20, 2012

Tropical Storm Alberto Still Meandering Off of the Southeast Coast...

At 10am CDT / 11am EDT this morning, the center of Tropical Storm Alberto was located about 90 miles South of Charleston, SC, or about 90 miles East/Southeast of Savannah, GA.  Alberto continues to wobble around a West to Southwesterly track, currently moving West/Southwest at 5 or 6 mph.

Maximum sustained winds were estimated at 45 mph, and the minimum central pressure is 29.53 inches of mercury.

Shower and thunderstorm activity extends Westward as far as southeast Georgia and the coastal areas of South Carolina:

An Air Force Hurricane Hunter aircraft will investigate the system this afternoon, and will provide a much more detailed picture as to the structure and intensity of Alberto.

In the near term, there are a couple of factors that move against any dramatic intensification of Alberto.  The first is present at this time, and involves a dry layer of air in the lower-levels of the atmosphere.  Some of this dry air is currently being entrained into the system and has likely resulted in the recent trend where the stronger thunderstorm activity is separating from the center of the storm.

The other factor involves a forecast of increasing wind shear in the middle and upper-levels of the atmosphere by late Monday and into Tuesday and Wednesday.  This will make it difficult for the storm to remain well organized, especially due to its relatively compact size.

Computer forecast models generally call for the system to assume a more Northeastward track later tonight and into Monday as the stronger Southwesterly flow aloft moves over the region:

Based on the current size of the wind field (tropical storm force winds extend out 70 miles from the center), and the forecast movement of the center, tropical storm force winds would remain offshore of the Carolina coasts during the lifetime of the system.  This will need to be closely monitored, as any Westward shift of the track and/or expansion of the wind field could have a dramatic effect on its impact to the Carolinas.  

In the meantime, increasing wave action and rip currents can be expected all along the Georgia and South Carolina coasts through Monday, and the extending Northward to the North Carolina coast by Tuesday.  

I'll have another update this afternoon as the Hurricane Hunter data comes in and is analysed.

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