Tuesday, May 30, 2017

Tropical Development in the Western Gulf of Mexico This Weekend? One Threat Looms Regardless

Jon Erdman
Published: May 30,2017

As the 2017 Atlantic hurricane season officially gets underway, we have our eyes on an area of the western Gulf of Mexico which may see a tropical depression or storm form by this weekend or early next week.
The threat of rainfall flooding will be in play, regardless of development, along parts of the Gulf Coast into next week.
For now, there's a broad area of surface low pressure, known as a trough, oriented roughly north-to-south over the western Gulf, along which a few clusters of thunderstorms are flaring periodically.
(MORE: Hurricane Central)

Current Infrared Satellite Image, Surface Pressure and Winds
One such those cluster is already producing heavy rain and localized flash flooding near the northern Gulf Coast.
(INTERACTIVE: Your Local Radar Loop)
Origin points of June named storms in the Atlantic basin from 1950 through 2016.

Current Satellite and Wind Shear






























 Will Something 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 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.
In this case, though, there are two negative factors that may work against a tropical depression or storm's formation:
1. Wind shear – the difference in wind speed and direction with height – is already high and isn't expected to 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. This may cut down slightly on instability to continue to fuel thunderstorms near any prospective areas of low pressure in that part of the Gulf.
Therefore, the chance of development of a depression or storm appears to be low, 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.
(MORE: 2017 Hurricane Season Outlook)

One Threat, Regardless of Development

Despite the low chance of a tropical depression or storm, the overall atmospheric setup into at least the first half of next week poses a threat of heavy rain and flash flooding.
(MAPS: 7-Day U.S. Daily Forecast | 48-Hour Rainfall Forecast)
The ingredients for heavy rainfall starting late this week.
A slow-moving upper-level disturbance will lazily glide east from Texas this weekend across the northern Gulf Coast states next week.
Ahead of this feature, deep tropical moisture will be drawn northward and northeastward into the Deep South and northern Gulf Coast.
Given this slow-moving pattern, there's a potential for repeated rounds of locally heavy rainfall from the upper Texas coast to possibly as far east as parts of Florida into next week.
With the ground already saturated over much of the zone, the threat of flash flooding is high.
(MORE: Flooding Nearly Three Times Deadlier in 2015-2016)
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.
MORE: Atlantic Basin's Retired Hurricane and Tropical Storm Names

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

No comments:

Post a Comment