TWC: Tropical Development? Gulf Coast Heavy Rain Threat, Regardless, Including Drought-Suffering Florida

Written by on June 2, 2017 in Spring 2017, Tropical, United States of America with 0 Comments

By Jon Erdman
Jun 2 2017 05:00 PM EDT

Story Highlights

An area of the Gulf of Mexico will be watched for possible tropical development into next week.
Possible development may involve a remnant of an eastern Pacific system.
This is an area prone to tropical development in June.
Regardless of development, heavy rain and flash flooding is a Gulf Coast threat well into next week.

This heavy rain threat is likely to include parts of drought-stricken Florida next week.
The chance of tropical development in the Gulf of Mexico is very low, but the threat of flooding is in play, regardless, along much of the Gulf Coast into next week, as the 2017 Atlantic hurricane season officially gets underway.

Interestingly enough, this potential Gulf development may be helped, in part, by a remnant of Tropical Storm Beatriz which is soaking southern Mexico and the Bay of Campeche.

For now, clusters of thunderstorms are flaring from time to time in the Gulf of Mexico.

What Does the Pacific System Have to Do With the Gulf?

Beatriz became a remnant low in southern Mexico on Friday morning but will continue to stream some remnant upper-level energy and moisture northward into the western Gulf this weekend.

Sometimes these “ghosts” of a past tropical cyclone can give a bit of extra oomph in the atmosphere (lift, instability) to help a fledgling area of low pressure develop into a tropical depression.
This may be the case in the western or central Gulf of Mexico into this weekend.

Will It Actually Develop?

As a matter of principle, clusters of convection over the Gulf of Mexico in or near hurricane season always should draw a meteorologist’s attention.

While the number of June named storms in the Atlantic basin is small – typically only one named storm every 1 to 2 years – the large majority of June tropical storms and hurricanes since 1950 have formed in the Gulf of Mexico, often on the tail end of old surface fronts or troughs.

Over the years, the Gulf of Mexico has provided several examples of tropical storms, even hurricanes, that developed quickly.
One of these was Allison in early June 2001, which produced historic, billion-dollar flooding in the Houston metro area.

Most computer forecast models have been quite consistent since last weekend depicting a broad area of low pressure forming in the Gulf of Mexico into this weekend or next week.
However, there are two negative factors working against its ability to become a distinct, closed circulation with sufficient, organized thunderstorms to be classified as a tropical depression or storm:

1. Wind shear – the difference in wind speed and direction with height – is already strong and chances are not high that these winds will slacken much. This may not allow thunderstorms to persist near the aforementioned surface trough long enough to begin the process of tropical depression formation.

2. Water temperatures in the northwestern and northern Gulf of Mexico are actually a bit cooler than average for this time of year. Although cooler than average, they are still supportive of tropical depression or storm formation throughout much of the Gulf until the entity reaches the northern Gulf coast. Any organization in the central and northern Gulf may be slow to occur.

Therefore, the chance of development of a depression or storm appears to be very low, but non-zero, for now. The next name on the Atlantic list is “Bret.” Just over a month ago, “Arlene” was only the second April Atlantic tropical storm in the satellite era.

One Threat, Regardless of Development

Despite the low chance of a tropical depression or storm, the overall atmospheric setup into next week poses a threat of heavy rain and flash flooding near the Gulf Coast and Florida Peninsula.

There’s a host of ingredients in play to raise the flash flood threat.
1) A deep flow of tropical moisture pushing toward the Gulf Coast
2) A slow-moving upper-level low over Texas adding instability to the atmosphere
3) An arriving frontal boundary, providing a focus to lift the warm, humid air
4) A sharp jet stream plunge into the East, which may induce an area of low pressure to form along the front, further focusing heavy rain

Repeated rounds of locally heavy rainfall are possible this weekend into next week from the upper Texas coast to the Florida Peninsula.
With the ground already saturated over much the northern Gulf Coast, the threat of flash flooding there is high.

While the weather pattern isn’t the same this time, remember the multi-billion-dollar flood event in Louisiana last August wasn’t officially accompanied by even a tropical depression.
Some spots in Florida have already seen 3 to 6 inches of rainfall the Orlando region and in Miami.
Around the middle of next week, a pulse of heavy rain may accompany a southward push of the aforementioned cold front and jet-stream plunge into Florida.

Next week could be the heaviest rain event in Tampa, Florida, since before Labor Day 2016.

While some localized flooding is possible in the Florida Peninsula and southern Georgia next week, this rain is also desperately needed, given the current severe to extreme drought and recent wildfires.

Follow us

Connect with Mark Vogan on social media to get notified about new posts and for the latest weather updates.

Subscribe via RSS Feed Connect on YouTube

Leave a Reply