Tropical Storm Maria & Invest 96 (9/7/2011)

Figure 1. IR satellite overview of Gulf of Mexico, Caribbean, and southern half of the Atlantic.

The tropical season is in full swing with Hurricane Katia in the western Atlantic, Tropical Storm Maria in the southern Atlantic, and a broad area of low pressure in the Bay of Campeche.  Katia will likely side-swipe the eastern coast of the U.S. and turn back out to sea.  I wanted to concentrate on newly formed Maria and the area of low pressure (Invest 96L) in the Bay of Campeche.

Formally tropical depression #14, Tropical Storm Maria gained strength over the past 12 hours as it moves west-northwest in the open Atlantic.  Convection associated with Maria isn’t very deep, but winds do favor tropical storm status.  Shear on the southern side of Maria(image below), as well as some drier air ahead of it, will hinder it from becoming a hurricane in the next 2-3 days.

Figure 2. IR satellite image of Tropical Storm Maria and plotted shear values in yellow. Blue line is its previous track.

Most dynamical and statistical models do keep Maria on a west-northwesterly track and then makes a turn more northwesterly by Friday.  There is still question as to how or if it will affect the U.S. and I will continue updating Maria’s track.  For now, here is the latest on Maria and its track from the National Hurricane Center:

SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...13.0N 42.0W
ABOUT 1220 MI...1965 KM W OF THE CAPE VERDE ISLANDS
ABOUT 1305 MI...2095 KM E OF THE LESSER ANTILLES
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 23 MPH...37 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES

Figure 3. NHC's forecast track of Maria over the next 5 days.

 

Invest 96

Figure 4. IR satellite image of Invest 96 with plotted dry air in orange and red.

Another area of low pressure that people from central Mexico to the west coast of Florida want to keep an eye on is trying to get better organized.  This system could become tropical depression #15 by the end of the day or in the next 24 hours.  Invest 96 has formed as a result of a surface frontal boundary that swept across the country during the weekend and early this week.  As you can see from the image above, there is a lot of dry air and subsidence north of the Bay of Campeche due to the front.  Any movement north will likely tear it apart.  Because there is little steering in the upper-levels right now, invest 96 will likely sit in the open waters until a ridge or trough directs its motion.  Models are in full disagreement of where and when this low pressure will go and strike.  I’m leaning toward the solution of a mid-level trough will provide a northerly track over the next 3-4 days.  We will have to wait and see what it does and I will continue monitoring it.

Figure 5. Today's 12Z statistical model (spaghetti plots) of where invest 96 will go.

About Brian

University of Oklahoma graduate with a degree in Meteorology. Follow me on Twitter: @WeatherInformer
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