Flood Science Storms Weather

Tropical Weather Micro-Update by Hurricane Hal

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October 5, 2020

Mon, Oct 5

1. Tropical Storm Gamma is centered north of the Yucatán Peninsula this morning with 45 mph winds. Gamma is forecast to drift to the southwest and remain a weak tropical storm due to wind shear and dry air. No threat to the U.S. Gulf Coast.

2. Tropical Storm Delta has formed south of Jamaica. Delta is forecast to track to the northwest and become a hurricane as it moves across the Gulf of Mexico. Conditions look favorable for strengthening and Delta could become a cat-2 hurricane in the Gulf.

3. The NHC cone of uncertainty gives a possible landfall window for Louisiana, Mississippi, Alabama and parts of the Florida Panhandle. An approaching trough should cause Delta to slow down and turn to the northeast before reaching the coast but uncertainty in the timing of this has created a broad area of uncertainty for landfall right now. This will tighten up by late Tuesday.

4. The NHC forecast places Delta as a cat-2 hurricane with 105 mph winds centered around 150 miles south of the Louisiana coast. This is the position shown on the uploaded map on Fri Oct 9 at 200AM. We would not expect to see additional strengthening beyond this time because water temps near the northern Gulf Coast are near the threshold temp for supporting hurricane development. Hurricanes need water temps of greater than 80F to sustain themselves or strengthen and the map shows the contour for 27C (80.6F) as far as 150 miles off the coast in some places and the water temp closer to shore less than 26C (78.8F). These cooler water temps may cause some weakening in the 9-12 hours before landfall.

5. Stay tuned to the CNC social media channels for frequent updates on TS/ Hurricane Delta this week. I will be on the ground in the impact area deploying our community flood monitoring system.

-HH