At a Glance
Hurricane Delta is over the Gulf of Mexico and has strengthened into a Category 2.
Delta is expected to landfall along the northern U.S. Gulf Coast on Friday, most likely in Louisiana.
Storm surge, destructive winds and flooding rain are all expected.
This includes areas ravaged by Hurricane Laura in late August.
A storm surge watch is also in effect from High Island, Texas, to Sabine Pass, Texas. This watch means a dangerous, life-threatening inundation from rising water moving inland is possible within 48 hours.
Tropical storm warnings are in effect from San Luis Pass to Sabine Pass, Texas; east of Morgan City, Louisiana, to the mouth of the Pearl River, including New Orleans, and for Lakes Pontchartrain and Maurepas. This means tropical storm-force winds are expected within the next 36 hours.
A tropical storm watch extends east of the mouth of the Pearl River to Bay St. Louis, Mississippi. This means tropical storm-force winds are possible.
Forecast Timing, Intensity
Delta has become better organized and is now a Category 2 with maximum sustained winds of 100 mph. The hurricane is moving northwestward at about 15 mph.
With a bubble of somewhat warmer Gulf of Mexico water and lower wind shear in its path, Delta is expected to continue strengthening through Thursday night.
Delta will also turn northward toward the U.S. Gulf Coast.
As it draws nearer to the Gulf Coast, Delta’s wind intensity could diminish somewhat due to increasingly unfavorable upper-level winds and cooler Gulf water.
Despite this weakening on approach, Delta is still forecast to be a formidable hurricane at landfall, most likely along the Louisiana or the extreme upper Texas coast on Friday.
Delta will then move inland over the lower Mississippi Valley this weekend as it weakens into a remnant area of low pressure.
Storm Surge, Waves
Swells generated by Delta should begin to arrive along the Gulf Coast, from South Texas to the Florida Panhandle and even western Florida Thursday.
These swells are likely to generate dangerous rip currents at beaches and could lead to some coastal flooding at high tide in some low-lying areas Thursday, particularly in southern Louisiana.
Delta’s storm surge will be dangerous and life-threatening regardless of any weakening of its winds up until landfall.
The highest storm surge is expected in parts of south-central Louisiana, not just near the immediate Gulf Coast, but also in bays, inlets and to some degree inland along rivers and bayous. Inundation could reach 7 to 11 feet above ground in these areas.
A dangerous storm surge is also expected in areas that were ravaged by Hurricane Laura in late August. Any potential shift westward in the forecast track could bring higher storm surge to these areas.
At least some storm surge flooding is also expected in southeast Louisiana, including along Lake Pontchartrain, and along the Mississippi and Alabama coasts, including areas affected by Hurricane Sally last month.
A faster forward speed than what we saw with Hurricane Sally last month will lessen Delta’s extreme rainfall potential, though heavy rainfall is still expected, particularly along and to the east of its path.
This heavy rainfall combined with storm surge could worsen and prolong flooding for a time along the northern Gulf Coast.
According to the National Hurricane Center, 5 to 10 inches, with isolated 15-inch amounts are expected with Delta in southwest and south-central Louisiana. This rainfall could cause flash flooding and minor to locally moderate river flooding.
Rainfall totals of 3 to 6 inches, with isolated 10-inch amounts are forecast in parts of extreme eastern Texas, southern Arkansas and western Mississippi.
Some locally heavy rainfall will also spread into the Ohio Valley, Southeast and mid-Atlantic this weekend.
As with most landfalling hurricanes and tropical storms, there’s also a threat of isolated tornadoes from Delta.
Southeast Louisiana and southern Mississippi have the greatest chance of seeing a few tornadoes Thursday night and Friday.
Tropical Depression Twenty-Six formed late Sunday evening to the south of Jamaica and then strengthened into Tropical Storm Delta on Monday morning, the 25th named storm of the 2020 Atlantic hurricane season.