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Posted at 01:30 PM ET, 07/18/2011

Tropical storm Bret offshore Florida drifting northeast, no threat to U.S.


Official National Hurricane Center track for Bret

An area of low pressure roughly 150 miles east-northeast of West Palm Beach, Fl. (2 p.m. position is 100 miles north of Great Abaco Island) became tropical storm Bret (latest visible satellite image) late last night. The storm is drifting northeastward away from the United States at 5 mph.

Maximum sustained winds are estimated to be near 50 mph, with some strengthening possible during the next day or so as it moves over warm water (mid-80s) and remains surrounded by relatively weak flow aloft. The official track directs Brett northeastward out to sea, never coming closer to the U.S. mainland than it is right now. However, tropical storm warnings are in effect for the northwest Bahamas including Grand Bahama Island and the Abaco Islands where 2-4 inches of rain and wind gusts of 40-50 mph are possible.


Outer edge of tropical storm Bret as seen from Ft. Lauderdale this morning (Steve Tracton)


Weather observations this morning along the Florida peninsula. Notice the wind arrows from the north along Florida’s East coast.
Observations taken this morning along the Florida East Coast indicate that the outer periphery of Bret’s circulation is bringing a gentle 5-15 mph northerly breeze to locations not used to seeing a north wind this time of year. The beaches from Jacksonville to Miami are expecting only little impact from Bret, with near-shore wave heights in the 3-6 foot range and a slightly elevated risk for rip currents.

As Bret moves northeastward, it may cause some higher than normal surf and rip currents along the Southeast and mid-Atlantic coasts through mid-to-late week.

Bret’s origins and future track

So where did Bret come from? Unlike Arlene, which developed from a tropical disturbance over the Caribbean, Bret was born in an entirely different environment … along a dying cold front that made it all the way down to North Florida.

This front brought relief from the excessive heat that blistered parts of the Southeast late last week. Northeasterly breezes and high temperatures in the 80s swooped southward from the Great Lakes into territory usually immune from late July cooling. As is the case with weak frontal zones that make it this far south this time of year, organized areas of thunderstorms near the boundary can sometimes mature into tropical systems in the absence of strong wind shear.

That’s what happened with Bret. The low-altitude counterclockwise swirl already present in the environmental wind near the front – with northeast breezes on its north side and southwest breezes on its south side - cooperated with the convection along it to tighten up the broad rotation into what we now call Bret.


Upper level steering currents that should keep Bret out to sea.
Bret’s near future will be largely governed by yet another non-tropical feature that will sink southward along the U.S. East Coast early this week. This one will not have much of a surface component (no significant surface fronts). It will, however, have just enough of a steering flow aloft (outlined in red) to direct Bret out to sea.

We will be watching this for you closely.

By  |  01:30 PM ET, 07/18/2011

Categories:  Tropical Weather, Latest

 
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