11 September 2014

Update on two tropical disturbances

11am EDIT: The eastern disturbance upgraded to Tropical Depression 6.

The quick version: neither one is a depression yet, but the eastern one is very close and the western one should remain weak but bring wet weather to FL in the coming days.

First, a look at the one that is over the Bahamas and headed for Florida.  It has not gotten much better organized, and time is running short for it to do anything.  It's now centered over the far northwestern Bahamas, and thunderstorm activity remains sparse.  Although the water temperature under it is plenty warm, the vertical wind shear is picking up and should restrict any rapid organization.

Visible satellite image from 9:30am... the approx center of the surface circulation is marked with a red X. (NASA)
So, it will continue drifting west and just bring enhanced rainfall and some gusty winds to parts of central and south Florida over the next 2-3 days.  A three-day rainfall forecast valid between Thursday morning and Sunday morning is shown below.  After crossing the FL peninsula, whatever remains will enter the Gulf, but there's too much uncertainty to speculate that far out... we'll have to wait to see if there's anything intact after crossing Florida.

72hr rainfall forecast, valid Thu 8am - Sun 8am. (NOAA/WPC)
I have a long and updating radar loop from Melbourne FL at http://andrew.rsmas.miami.edu/bmcnoldy/tropics/al92/AL92_11-12Sep14_MLBlong.gif.

Now onto the eastern disturbance, which is close to becoming a tropical depression or tropical storm.  It's centered about 800 miles west of the Cape Verde islands this morning... and moving west-northwest at about 15mph.

Visible satellite image from 9:15am.  (NRLMRY)
It is forecast the gradually strengthen, possibly reaching hurricane intensity early next week, but also recurve by 50W, never coming close to any land.  If named, the next name on the list is Edouard.

Trivia for today: the last time the fifth named storm occurred so late in the season was 20 years ago!  Ernesto was named on Sept 22, 1994.

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