We are now at that time of year when the tropics ramp up quickly as robust tropical waves that come off of the African Coast, near the Cape Verde Islands, have increased potential for hurricane development.
Danielle was the first this year with another candidate looking to become “Earl” before the week is done.
All indicators for an active tropical season remain present, including very warm ocean temperatures, lower than normal tropical surface pressures, and favorable upper level winds associated with La Nina.
There remain two “wild cards” as we have mentioned over the last several weeks…dry Saharan air with dust has been a storm “mitigator” over the last several weeks, and probably has had impact on Danielle today. This dust should become less of a factor over the next week or two as more regular and wetter waves traverse the southern Saharan Desert.
The second wild card: upper level lows, that present interupting shear, have also inhibited some development so far this summer. These upper lows have been theorized to be more robust and numerous in hotter summers.
There is no indication one way or another whether these features will continue to be a factor as we head into the heart of hurricane season.
Factoring all the variables, it is still expected that on average we will likely be talking about 1-2 tropical systems per week through at least the second week of October. How many of these systems will threaten the Gulf of Mexico and the East Coast of the U.S. remains to be seen.
In the near term and closer to home, deep tropical moisture will be pooling along a decaying frontal boundary in the Western Gulf of Mexico through the end of the week. This moisture should bring higher rain chances and the threat of soaking rains back to Acadiana just in time for the weekend.