First Alert Weather


FIRST ALERT: Here are the factors we're watching for the Gulf storm system

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Posted at 5:00 PM, May 24, 2018
and last updated 2018-05-30 12:59:21-04

MIDWAY, Fla. (WTXL) -- Interest in the ragged but moisture-laden disturbance in the western Caribbean, currently dubbed "Invest 90L," will continue to increase as we gauge its development chances and effects on the local Memorial Day weekend weather pattern.

The poorly organized low is hovering near the Yucatan Peninsula, in a region of rather weak atmospheric winds, causing the system to move erratically and slowly.  Because it is near land, rapid strengthening and organization is not expected in the short-term.

As the disturbance starts to drift into the southernmost Gulf of Mexico, the low can use the warm water temperatures to support a stronger low-pressure circulation.  However, the development will be impacted by a zone of modest upper-level winds in the western Gulf that can interfere with organization efforts by "forcing" most of the moisture and cloud development to the eastern side of the low.  There is also a considerable amount of dry air contained within the upper winds, which will adversely effect organization efforts through the weekend.

We are also monitoring the position of high pressure over the Atlantic Ocean. Its western flank is draped over most of Florida and Georgia. High pressure acts as a resistance against low-pressure areas, causing them to move on the outer edge of the high-pressure ridge.

The combination of these factors have led to the expectation for further development of the system into a subtropical (warm- and cool-air disturbance influenced by high-level atmospheric wind patterns) or tropical (purely warm-core, surface-based) cyclone this weekend.

If the high stays in place over the Atlantic and Florida, the low will likely move more to the north, directing it toward the central Gulf coast.  Upper-level winds may try to nudge the system slightly to the east, but its eastward movement should be limited because of the presence of the high-pressure system in the Atlantic.

Regardless of whether the disturbance remains unclassified, or becomes a tropical storm (which would be named Alberto if it reaches that level), the local effects will be primarily rain, which can accumulate to several inches over the next five days.  High amounts of rainfall can trigger flooding issues, particularly near rivers and some poor drainage areas.