Tropics are on Fire. Invest 92L: A Storm to Keep a Close Eye on.
Updated July 25, 2020 @ 4:55pm EST
Current areas of interest in the North Atlantic Basin and over towards the Gulf of Mexico. Taken on July 25, 2020 (Courtesy of the National Hurricane Center).
Late July and already the tropics are catching fire. Hurricane Hanna, our first hurricane of the 2020 Atlantic Hurricane Season is quickly approaching the Texas coastline and will continue to move further inland over the Rio Grande Valley and towards northern Mexico.
Hurricane Hanna, the first hurricane of the 2020 Atlantic Hurricane Season approaching the Texas Gulf Coast on July 25, 2020 (Courtesy NOAA).
Elsewhere, Tropical Storm Gonzalo weakened back to a Tropical Depression on Saturday as it approached the southern Windward Islands. Nevertheless, heavy rains and gusty winds are expected to continue to fall across the small islands through Sunday and possibly into Monday. What was interesting about this particular storm was where is formed. A very tropical location close to the equator. Typically storms that develop in this area track directly westward and impact the Lesser Antilles before crossing into the Caribbean Sea. Gonzalo did track westward, for the most part, but it was so far south in latitude that it was bring some rain showers to parts of Venezuela, which does not typically happen. Most tropical cyclones keep their distance from South America and are generally far enough north that they do not bring any impacts to these areas. The good news is that Gonzalo will not be posing a threat for much longer to any Caribbean areas as it continues to weaken as it exits out into the Caribbean Sea.
Tropical Depression Gonzalo in the far south Windward Islands quickly weakening on July 25, 2020 (Courtesy NOAA).
The main topic of the week will be a large area of disturbed weather that is still days away from any landmass.
Invest 92L taken on July 25, 2020 off the west coast of Africa (Courtesy NOAA).
While it is not classified as a Tropical Depression it is still very impressive on satellite. The National Hurricane Center is currently referring to it as Invest 92L (an area under investigation).
This tropical wave began to come off the west coast of Africa Thursday and Friday and immediately started to take advantage of the warm sea surface temperatures (SSTs) and the open space far from any land mass areas. Once again, it is not a cyclone yet, but it is an area that forecasters have been watching the past few days and it has a very good chance of increasing in strength as it moves generally westward over the next several days. This is a perfect example of a Cape Verde Cyclone (even though it is not named yet) which are the ones that we should pay very close attention to. Cape Verde Cyclones develop near and around the Cape Verde Islands which lie just to the west of the African continent. These cyclones are formidable because they have ample amount of time to grow and intensify as they track towards the west and approach the Caribbean nations and the United States. An average hurricane season generally sees about 2-3 Cape Verde Cyclones, but given how active this year already is, we may be seeing a few more of these. Hurricane Hugo (1989), Hurricane Ivan (2004), and Hurricane Irma (2017) are three examples of Cape Verde Cyclones which caused massive destruction during their respected hurricanes seasons.
The National Hurricane Center at this time is giving this large cluster of showers and thunderstorms a 20% chance of development within the next 48 hours and a much higher, 70% chance, of development over the next 5 days, placing the storms around the central Tropical Atlantic, close to where Tropical Storm Gonzalo formed last week. Here is the main difference between Gonzalo and this upcoming storm though: latitude. Latitude is very important when it comes to development. Storms that form closer to the equator usually track due west and cross into the Caribbean Sea. However, further north in latitude and the track usually begins to pivot northward as the storm moves close to the continental United States. Usually colliding with some of the Greater Antilles. We are already anticipating this slight pivot northward by the time it gets to the central Atlantic but there is still the chance that it could track due west and push into the Caribbean.
Tropical activity in the North Atlantic as of the afternoon of July 25, 2020 and projections on intensification (Courtesy National Hurricane Center).
Weather models are starting to come into agreement with this pivot northward and this could make a few Floridians and southeast residents raise an eyebrow. I am not a fan of sharing models this far out as there are so many uncertainties, however, it is a good heads up to residents along the southeast United States that we are entering into the active part of the Hurricane Season (August through October) and conditions are likely just going to continue to get more active.
The first model we will look at is the American Model (GFS) and the estimated location and strength the storm could be around August 4, 2020. Keep in mind, all of these models are just estimates based on atmospheric conditions over the next several days, they are not solidified in stone and should not be used to make decisions at this time.
GFS model showing a FORECAST for August 4, 2020 and where Invest 92L MIGHT be, this is not to be used to make decisions and is only an ESTIMATE (this will be subject to change in the coming days as more information becomes available).
The GFS is so far anticipating a low pressure system with a barometric pressure of about 975mb (fairly strong hurricane typically on the Saffir-Simpson Hurricane Scale) impacting around the Space Coast or First Coast before traveling inland over North Florida and quickly pivoting away back towards the east over the southeast United States. This is not the whole story, if anything this is just a “nightmare” model that likes to cause fear.
Ensemble models for the GFS showing most of the projections staying offshore (these will be subject to change in the coming days as more information becomes available).
When we look at the ensemble models we see better news which show the majority of the tracks turning away from the State of Florida but still maintaining “decent” hurricane strength.
Another model we look at (and in recent years favor) is the European Model, which at this time shows some better news for August 4. Invest 92L is indeed expected to be strong and probably a hurricane but it is curving to the north staying away from the coast of Florida. This model will continue to project into the future with our next main concern being: will it turn completely back out to sea, or would the Carolinas be at risk? It will be a close call no matter what and even if it stays offshore, heavy surf and coastal flooding will be likely (all of this considering if the storm makes it to this point and is relatively strong).
Euro model showing a FORECAST for August 4, 2020 and where Invest 92L MIGHT be, this is not to be used to make decisions and is only an ESTIMATE (this will be subject to change in the coming days as more information becomes available).
All models available at this time are in agreement on one thing thought, Invest 92L will likely continue to strengthen over the next several days and could become a Category 1 hurricane in the 4-6 days.
Estimated intensity of Invest 92L over the next 168 hours. This is not to be used to make decisions and is only an ESTIMATE (this will be subject to change in the coming days as more information becomes available).
This is very likely given how warm the sea surface temperatures are across the tropical Atlantic and the diminished wind shear in the higher layers of the atmosphere. Both of these favor tropical cyclones and allows them to intensify, sometimes quickly.
Wind shear levels across the North Atlantic Basin and the Gulf of Mexico. Red depicts high wind shear/not favorable for cyclone development. Blues and greens show favorable areas for potential development.
Aside from a patch of high wind shear (depicted in red) right where Invest 92L is currently located the rest of the tropical Atlantic remains “healthy” for cyclone formation. What will likely happen is Invest 92L will take advantage of this prime environment, quickly strengthen, and track westward before tilting slightly northward as it approaches the Lesser Antilles.
I cannot emphasize this enough, this is a storm that is still over a week away from any impact on the continental United States, but it is certainly one that we should keep an eye on given its location, impressive size and formation, and the fact that we are heading into the active hurricane season months.
Given the ongoing pandemic it is recommended that residents begin to stock up now ahead of this storm and not wait until the last minute. Whether this storm impacts a landmass or not, this is only the beginning of what is likely to be a very active hurricane season.