Tropical Low Brewing in the Caribbean Father’s Day Weekend

Chances continue to increase for a tropical low to develop in the Caribbean for Father’s Day weekend. The time-frame for any tropical formation is Sunday-Tuesday.

So the big question on everyone’s minds, will we have a tropical storm in the Gulf of Mexico?

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Infrared Satellite of the northwestern Caribbean valid for 17:00Z.

The answer is much more complicated than a simple “yes” or “no”. Storminess is beginning to increase across the northwestern Caribbean, however a disturbance has not been detected yet and Wilkens Weather is not expecting tropical development over the next 24 hours. Several factors are analyzed when forecasting tropical weather including sea surface temperatures (SST), vertical wind shear, and tropical atmospheric moisture. The sea surface temperatures in the southern Gulf are around 28°C, indicating favorable conditions for development. Atmospheric moisture, explained in a previous blog here, surges into the southern Gulf this weekend providing ideal conditions for tropical development. The third and final key ingredient meteorologists are monitoring is vertical wind shear. Light winds are vital to sustain and strengthen the structure of tropical systems.Read More »

Tropical development in the Gulf this weekend?

With hurricane season officially underway today in the Atlantic basin, all eyes are on thunderstorms streaming northward across the Gulf of Mexico. This convection is associated with Tropical Storm Beatriz off the coast of Mexico in the East Pacific. Although Beatriz is not a direct threat to the Gulf, tropical moisture from this storm will continue to provide deep convection across the southern Gulf. This moisture will interact with an existing surface trough over the Bay of Campeche providing the potential for low pressure to develop over the weekend, but there are limiting factors for tropical development.

Regardless of tropical development, one key tropical ingredient is present: atmospheric moisture. The higher the moisture content in the atmosphere, the greater chance for deep, persistent convection which furthermore enhances development within tropical systems. Meteorologists analyze a parameter known as PWAT, Precipitable Water, to gauge atmospheric moisture content. NOAA defines PWAT as the “measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column over a given location”. Imagine having a column of water vapor, from Earth’s surface to the top of the atmosphere, and squeezing that column of air until all the water fell out (very similar to wringing out a sponge). The resulting measure of water, calculated in inches, is a good indicator of how much rainfall a region could see.

PWAT Animated Loop
Simulation of PWAT values for the Gulf of Mexico valid June 2-4, 2017.

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