*******Note that forecast and outlooks in this post are NOT the official forecast from the National Hurricane Center (NHC). They are my own detailed views on the Atlantic tropics based on current observations and latest computer model runs. As such do not make decisions based on my posts...consult news media...watches and warnings from your local weather office...and any evacuation orders issued by local governments to make the most informed and best decisions. Visit the NHC website hurricanes.gov (hurricanes dot gov) for the latest watches/warnings and official forecasts on active tropical cyclones.*********
...THURSDAY AUGUST 22 2024 12:30 AM EDT...
Within the next few days... the area in the Atlantic basin that is the most likely to see possible tropical development remains the Gulf of Mexico as follows:
Over the last couple of days a tropical wave of low pressure which emerged from the coast of Mauritania... which featured a lack of thunderstorms as its northern position allowed it to more easily ingest dry Saharan air... and another tropical wave of low pressure featuring curved thunderstorm bands that was racing across western Africa... have merged into a singular large tropical wave over offshore eastern Atlantic waters and the Republic of Cabo Verde Islands. Tropical development of this feature is not expected as the large wave continues to ingest dry Saharan air.
Satellite imagery over Africa (https://www.goes.noaa.gov/FULLDISK/GMIR.JPG) shows another large tropical wave of low pressure... featuring curved thunderstorm bands... is now moving into central Africa from eastern Africa. However upper-level winds across the tropical latitudes of the Atlantic... when this wave later departs Africa in about four days... are currently forecast to be less conducive for tropical development as follows... (1) a cold core upper vortex is forecast to coalesce in the vicinity of western Europe in association with the cold sector of the current surface frontal cyclone that is absorbing ex-Ernesto and currently heading into Europe... (2) a portion of the cold core upper vorticity by day 4 is currently forecast to be pushed south into the Atlantic tropics by the current central Atlantic upper ridge. Therefore this tropical wave is also not forecast to undergo tropical development when it later reaches the tropical Atlantic.
A shortwave upper trough currently over the eastern United States for the next few days is forecast to dive south into the Gulf of Mexico... then west across the Gulf as an upper vortex... while continuing to anticyclonically revolve around the steering central North America upper ridge. In the days ahead will watch to see if divergence between the periphery of the forecast upper vortex and surrounding upper flow results in a tropical disturbance in Gulf of Mexico. Any disturbance that does develop is likely to shift west toward the Texas coast as steering surface ridging remains intact to the north of the Gulf... supported by the convergence zone of high-latitude upper troughs expected pass to the north of the central North America upper ridge. Note the 1200Z CMC model run from Wednesday was beginning to pick up on possible Gulf development in the days ahead... see the CMC model run in the computer model summary section below for more details.
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
1200Z (Aug 21) CMC Model Run...
**Divergence between southwest side of south-diving eastern US shortwave upper trough and southeast side of central North America upper ridge produces a surface trough offshore of southeastern Louisiana at 66 hours... trough moves west into the northwest Gulf of Mexico (28N-94W) through 78 hours while evolving into a surface low... surface low makes landfall on the south Texas coast at 102+ hours which ends tropical development potential.
**Above-mentioned shortwave upper trough begins retrograding west across the Gulf of Mexico as an upper vortex in 5+ days... north side of large tropical wave currently crossing the eastern Caribbean interacts with eastern divergence zone of upper vortex to evolve into a west Gulf surface low near 25.5N-94W at 150 hours... strengthens further to a possible tropical depression just offshore of the south Texas coast through 168 hours
1200Z (Aug 21) ECMWF Model Run...
**No tropical development shown in Atlantic basin through 7 days (168 hours)
1800Z (Aug 21) GFS Model Run...
***No tropical development shown in Atlantic basin through 7 days (168 hours)
1800Z (Aug 21) NAVGEM Model Run...
**Model run not available at above-mentioned source
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