11:50 AM (Tuesday) | **Continuing to monitor a tropical wave that soon should be named “Isaias” - it could threaten Florida and the Southeast US by late in the weekend**
Paul Dorian
The latest satellite imagery animation features a large tropical wave (lower, middle) in the central Atlantic (tropical cyclone #9) - still without a well-defined circulation center. A kind of “milky haze” can be seen surrounding the tropical system which is related to Sahara Desert dry air that has been an inhibiting factor for intensification in recent days. The circulation center should become better defined in coming days, however, as more favorable environmental conditions develop (i.e., less dry air) and likely lead to intensification. Another tropical wave can be seen trailing the first one in the eastern Atlantic (lower, right). Images courtesy NOAA, College of DuPage
Overview
The 2020 Atlantic Basin tropical season has gotten off to an active start with eight named storms already and another (still unnamed) wave closing in on the Lesser Antilles. This latest tropical wave pushed off the west coast of Africa late last week and is likely to intensify over the next couple of days as it continues on a general west-to-northwest track. There is a high probability that this system intensifies enough to become classified as a tropical storm and, if so, it would be named “Isaias” – the ninth named storm of the still relatively young 2020 tropical season and the earliest date for the “I” storm. There is a good chance that this system continues on a track that’ll bring it to near Puerto Rico later this week and then to the southern Bahama Islands at weeks end. After that, there is a growing chance that the likely-to-be-named “Isaias” will threaten Florida and the Southeast US by the latter part of the upcoming weekend.
Tropical cyclone #9 pushed off the west coast of Africa late last week and has moved on a general west-to-northwest track into the central part of the tropical Atlantic. Map courtesy NOAA, ESRI
Details
A large tropical wave pushed off the west coast of Africa late last week and it has progressed at a steady pace into the central tropical Atlantic. The latest movement of tropical cyclone #9 is to the west at a fairly rapid clip of 23 mph. This system has taken a track slightly to the north of the one taken by Tropical Storm Gonzalo last week which dissipated over the weekend after an encounter with dry (Saharan desert) air and increased wind shear. This newest tropical wave remains rather large at mid-day Tuesday, and it still features a rather broad circulation pattern that is quite elongated and lacks a well-defined center. One of the reasons for the lack of intensification in recent days has been the systems proximity to the same dry (desert) air that helped to weaken Gonzalo; however, environmental conditions should become more favorable over the next couple of days as it “escapes” the dry air. As a result, tropical cyclone #9 could very well reach tropical storm status and named “Isaias” before it reaches the Leeward Islands later in the week. If indeed this system becomes the named “I” storm for this season then it would best the prior earliest date for the ninth named tropical storm by several days (“Irene” on August 7th, 2005).
A series of computer forecast model tracks are shown for tropical cyclone #9 over the next several days with NOAA’s official National Hurricane Center path shown in black. Map courtesy NOAA, weathermodels.com (Dr. Ryan Maue, Twitter)
After a likely interaction with the Leeward Islands, a continuing west-to-northwest track would bring the tropical system to near Puerto Rico later in the week and then close the southern Bahamas by week’s end. Ultimately, this tropical system could head right towards the Florida Peninsula and the Southeast US by the latter stages of the upcoming weekend. Its eventual track will likely depend on a couple of factors including the intensity of the storm and also on the progression of an upper-level trough that will “dig” into the south-central states over the upcoming weekend. A stronger tropical cyclone is likely to favor a more northern track while a weaker system may result in it staying farther to the south. The strength of the tropical system will not only depend on environmental conditions - which should become more favorable shortly - but also on its possible land interactions in coming days.
NOAA’s National Hurricane Center has a forecasted storm track that would bring tropical cyclone #9 to near Puerto Rico on Thursday, to near the southern Bahama Islands on Friday, and potentially to Florida by late in the upcoming weekend. Map courtesy NOAA/NHC
Stay tuned…still a bit too early for specifics on the growing chance for an impact in the Southeast US later this weekend by the soon-to-be-named “Isaias”.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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