*******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.*********
...FRIDAY AUGUST 23 2024 11:15 PM 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... see area of interest #18 section below for more information.
Elsewhere... satellite imagery shows a vigorous tropical wave of low pressure with widespread thunderstorms that is continuing rapidly west across western Africa from central Africa. The tropical wave is expected to enter the eastern Atlantic tropics within the next couple of days. However the current eastern Atlantic upper vorticity... and a portion of the current Icelandic upper vortex... are forecast to descend southward overtop this tropical wave while pushed by the current central Atlantic upper ridge... with the overhead wave of upper vorticity suppressing outflow needed for tropical development. Therefore this tropical wave is not forecast to develop.
AREA OF INTEREST #18... A broad tropical disturbance appears to be materializing in the vicinity of the western Bahamas and Cuba... featuring cyclonic turning in the clouds and scattered thunderstorms. The surface low pressure vorticity of the disturbance appears to be a merger between the tail end of the surface front that was driven toward the region by the slow-moving frontal low that has been over the northeastern US and southeastern Canada border region over the last couple of days... and the north end of the surface tropical wave that has been recently crossing the Caribbean. Recent NHC TAFB surface analyses have marked the emerging disturbance as a pair of surface troughs. Because the forecast track of the disturbance in the days ahead is in alignment with upper winds potentially favorable for tropical development... I have introduced it as a tropical area of interest for the Atlantic basin... the eighteenth such area of interest I have tracked on this site this year.
Through the next 72 hours steering surface ridging remains intact to the north of the disturbance while becoming supported by the western convergence zone of the current central Canada upper trough that will dive southeast around the central North America upper ridge... resulting in the disturbance shifting west across the Florida peninsula and into the Gulf of Mexico. During this time the central North America upper ridge will also push the current eastern Gulf of Mexico upper trough/vortex westward into Texas... with this disturbance staying aligned with an upper anticyclone (favorable low shear/outflow environment) that manifests in the relatively higher upper pressures between the southeastward-diving eastern North America upper trough and Texas upper trough/vortex. However I currently assign a low 10% chance of tropical cyclone formation as the CMC and GFS models... which were the only models in recent days that showed Gulf of Mexico tropical development... have stopped doing so. For the longer-range... 96 to 120 hours... the next mid-latitude upper troughs approaching from western North America are currently forecast to weaken the steering surface ridge which results in a slow-down and northward turn toward southwestern Louisiana in the current forecast track shown below. The northward turn may also be aided by the Texas upper trough/vortex getting kicked back east toward this disturbance by the approaching mid-latitude upper troughs... which could result in some increase in shear or outflow blockage from the west but at the same time possibly enhancing the disturbance with its eastern divergence zone. Thus I keep 10% odds of development through 120 hours.
In the short-term (next couple of days) the disturbance could bring additional scattered thunderstorms and heavy rainfall across Cuba and the northwestern Bahamas... shifting west across the Florida peninsula. If the disturbance remains intact as it treks the Gulf of Mexico... southeastern Texas and/or Louisiana may see a round of heavy rainfall from this system by the middle of this upcoming week.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Aug 25)... 0% chance of tropical cyclone formation (southeast coast of the Florida peninsula near 25.8N-80.1W)
IOH 48 Hr Outlook (0000Z Aug 26)... 10% chance of tropical cyclone formation (eastern Gulf of Mexico near 25.8N-84.5W)
IOH 72 Hr Outlook (0000Z Aug 27)... 10% chance of tropical cyclone formation (eastern Gulf of Mexico near 25.8N-89.5W)
IOH 96 Hr Outlook (0000Z Aug 28)... 10% chance of tropical cyclone formation (western Gulf of Mexico near 25.8N-92W)
IOH 120 Hr Outlook (0000Z Aug 29)... 10% chance of tropical cyclone formation (offshore of southwestern Louisiana near 27N-93W)
*****National Hurricane Center (hurricanes.gov) official outlook as of 8 PM EDT***************************
Not in the official outlook
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
1200Z (Aug 23) CMC Model Run...
**For area of interest #18... no development shown
**Tropical wave currently over western Africa emerges into the tropical Atlantic at 36 hours and moves over the Republic of Cabo Verde Islands by 78 hours as a broad tropical low which becomes suppressed by eastern Atlantic upper vorticity that descends southward on top of the surface wave... the surface wave then moves only slowly west after that time due to the tug of an additional wave that approaches from the east while the suppressing upper vorticity moves west and away such that the surface wave is able to re-develop into a tropical low near 11.5N-37.5W by 168 hours
1200Z (Aug 23) ECMWF Model Run...
**For area of interest #18... no development shown
1800Z (Aug 23) GFS Model Run...
**For area of interest #18... no development shown
1800Z (Aug 23) NAVGEM Model Run...
**Model run not available at above-mentioned source
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