07 September 2011

Katia weakens, Maria forms

Katia continues to lose its organization in the face of increasing vertical shear.  At 15Z today, the intensity is down to 75kts, and the forecast is for a very gradual weakening and loss of tropical characteristics. It is going to pass over a buoy located near 32N 70W later today... you can view observations (wave height, wind, pressure, etc) at http://www.ndbc.noaa.gov/station_page.php?station=41048  The infrared image below shows Katia, then Bermuda is the yellow speck near 32N 65W, and the buoy I mentioned is shown by the red dot.

Shortly after I sent out yesterday's update, the easterly wave that was near 35W was upgraded to TD14.  Then 18 hours later (15Z today), it was upgraded to Tropical Storm Maria, the 13th named storm of the season.  Maria's estimated intensity is 45kts with a 1003mb central pressure.  It's located at 13N 42W (about 1300 miles east of the Lesser Antilles) and cruising westward at 20kts.  The environment that it's in is only marginal for intensification... the SST is a healthy 28C, but the vertical shear is 12kts and increasing.  So, it will probably just slowly strengthen over the next several days, while tracking WNW toward the northern Leeward Islands.  This is a storm to keep a very close eye on if you're on the US coast; though at this point it's too early to say if it's heading for the Gulf coast or the east coast.

The trailing end of a front extending from the northeast US through Florida and into the Gulf of Mexico has been showing signs of organization.  The front ends in the Bay of Campeche, and the pressures are dropping in the area... with this disturbance at approximately 1007mb.  The 06Z surface analysis shown below illustrates the position of the front, and the terminal Low in the Bay of Campeche.  Also note the Low in western VA/NC associated with the remnants of TS Lee.

The steering flow in this area is very weak, so it's not going anywhere in a hurry.  It's also surrounded by dry air, so even if it does make to a TD or TS, it shouldn't get much stronger.  If named, the next name on the list is Nate.

Please visit my tropical Atlantic headquarters.

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