*******Note that forecasts 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.**********
…WEDNESDAY JUNE 22 2022 1:19 AM EDT...
The surface low forecast to develop over the mid-Atlantic US in the next 24 hours… in response to split flow upper divergence between the deep-layer ridge to the west and an upper vortex to the east to soon be left behind by the current west Atlantic upper trough… is expected to swing east into offshore waters soon after its formation. The latest model consensus is for a more south track of the surface low more aligned with the ribbon of warm northwest Atlantic Gulf Stream waters… as a result there is potential for the surface low to become a short-lived tropical cyclone. See area of interest #7 section below for more information.
Elsewhere… a string of cut-off upper vorticity is currently settling across the Bay of Campeche… the northwestern Caribbean Sea… and western Atlantic near the northern Caribbean islands. Upper divergence between the south side of this upper vorticity and north side of a low-latitude tropical upper ridge over Central America and southern Caribbean may trigger thunderstorm activity in the central Caribbean in 24 hours… with upper winds becoming more conducive for tropical development shortly thereafter as the upper vorticity string weakens while remaining cut-off from high-latitude cold air which would reduce wind shear and allow the tropical upper ridge and its supportive outflow to expand. This could result in a central Caribbean tropical disturbance in the near term. Alternatively a central Caribbean disturbance could form in the longer range… in 5 days… in split flow upper divergence between the west side of the remaining upper vorticity to be located to the northeast and east side of the expanded tropical upper ridge. In summary… will be watching for the possible formation of an area of interest in the central Caribbean in the days ahead.
For the eastern tropical Atlantic… conditions for tropical development have been generally improving over the last several days with a reduction in dry Saharan air… the establishment of a strong deep-layer ridge in the eastern Atlantic which will generally keep wind shear low… and the establishment of a low-latitude tropical upper ridge conducive for upper outflow. Various model runs suggest the tropical wave of low pressure currently near the Republic of Cabo Verde Islands… or the tropical wave currently entering the Atlantic from the west coast of Africa… may gradually develop in the days ahead while continuing west. Will add an area of interest as needed in future updates.
New to this site this year… I will be sequentially numbering up areas of interest for possible Atlantic tropical development. In this scheme… will reset back to #1 at the start of next year (January 2023). The current area of interest in this blog post is designated #7 as I designated the other six of this year in previous birdseye view posts on the home page. This scheme is to reduce confusion as Atlantic tropical activity increases during the peak of the hurricane season… when multiple simultaneous areas of interest begin and end which previously required shuffling around the area of interest numbers from update to update.
AREA OF INTEREST #7… See the above intro section of this blog post and computer model summary below for the mechanisms expected to generate a surface low pressure over the US mid-Atlantic region over the next 24 hours. Shortly thereafter… the surface low is expected to swing east and then northeast into and across the northwest Atlantic while pulled around the southern and eastern edges of the cut-off upper vortex slated to be in the western Atlantic. The best opportunity for tropical cyclone formation is the 48 to 60 hour window as the surface low tracks over or near the narrow ribbon of warm Gulf Stream waters. Tropical development is not expected after 60 hours while the surface low moves into cooler waters. I assign a low 10% peak odds of tropical cyclone formation due to the narrow nature of the warm water swath… with a sizeable chance the surface low misses it. In addition the half of the surface low located toward the upper vortex may see upper outflow and hence thunderstorm suppression.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Jun 23)… 0% chance of tropical cyclone formation (eastern North Carolina near 35N-77.5W)
IOH 48 Hr Outlook (0000Z Jun 24)… 10% chance of tropical cyclone formation (western Atlantic near 34N-72.5W)
IOH 72 Hr Outlook (0000Z Jun 25)… 0% chance of tropical cyclone formation (western Atlantic near 37.5N-65W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z (Jun 21) CMC Model Run...
**For area of interest #7… Current west Atlantic upper trough deposits upper vortex offshore of the eastern US at 24 hours… split flow upper divergence between the west side of the vortex and east side of the current US deep-layer ridge generates a surface low over eastern North Carolina at 36 hours… moves northeast into offshore waters and reaches 38.5N-67.5W at 120 hours
**Tropical wave currently entering the Atlantic from the west coast of Africa evolves into a tropical low near 7.5N-32.5W at 90 hours… tropical cyclone formation near 8N-43.5W at 144 hours
1200Z (Jun 21) ECMWF Model Run.…
** For area of interest #7… Current west Atlantic upper trough deposits upper vortex offshore of the eastern US at 24 hours… split flow upper divergence between the west side of the vortex and east side of the current US deep-layer ridge generates a broad surface low over the coast of North Carolina shortly thereafter… within the east side of the broad low tropical cyclone formation occurs near 33.8N-71.5W at 48 hours… while continuing northeast away from warm Gulf Stream waters weakens to a remnant low offshore of Nova Scotia by 96 hours
**Current broad tropical low in the vicinity of the Republic of Cabo Verde Islands continues across the tropical Atlantic as a tropical wave… crosses the southern Lesser Antilles and southeastern Caribbean Sea at 144 to 168 hours while redeveloping into a tropical low.
1800Z (Jun 21) GFS Model Run...
** For area of interest #7… Current west Atlantic upper trough deposits upper vortex offshore of the eastern US at 24 hours… split flow upper divergence between the west side of the vortex and east side of the current US deep-layer ridge generates a surface low over North Carolina at 30 hours… surface low moves east into offshore waters and reaches 34.8N-72W at 48 hours… turns northeast and weakens to a surface trough offshore of Nova Scotia at 96 hours
**Surface low becomes defined in the southern Caribbean Sea near 11.5N-79.5W at 111 hours… surface low becomes brood at a location just east of Nicaragua at 150 hours
1800Z (Jun 21) NAVGEM Model Run...
** For area of interest #7… Current west Atlantic upper trough deposits upper vortex offshore of the eastern US at 24 hours… split flow upper divergence between the west side of the vortex and east side of the current US deep-layer ridge generates a surface low over the eastern NC/VA border at 36 hours… surface low moves east into offshore waters and reaches 36N-72W at 60 hours… surface low becomes generally stationary while whirling cyclonically beneath the upper vortex and weakens to a surface trough near 36.5N-73W at 120 hours due to a lack of divergence directly beneath the upper vortex.
** Surface low becomes defined in the southern Caribbean Sea near 11N-78.5W at 126 hours…drifts west to the waters just offshore of the Nicaragua/Costa Rica border by 150 hours
** Tropical wave currently entering the Atlantic from the west coast of Africa evolves into a tropical low near 7.5N-27.5W at 96 hours… tropical low reaches 11N-40.5W at 120 hours.