*******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.**********
…MONDAY JUNE 20 2022 10:09 PM EDT...
The current deep-layer ridge over the United States is in the process of cutting off some of the upper vorticity from the current eastern Canada to northwest Atlantic upper trough. Over the next couple of days the cut-off upper vorticity string is expected to settle 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 by 48 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. An alternate solution was shown in the 18Z GFS with a tropical disturbance forming later… in 6 days… in split flow upper divergence between the west side of the remaining upper vorticity 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.
Elsewhere… the current deep-layer ridge over the United States is also expected to cut-off a large portion of the current eastern Canada to northwest Atlantic upper trough into an upper vortex offshore of the eastern US. Computer models have come into increasing agreement that split flow upper divergence between the west side of the upper vortex and east side of the deep-layer ridge will induce a surface low pressure over the mid-Atlantic US in the timeframe now 2 days away… with the surface low subsequently pivoting eastward and then northeastward into offshore Atlantic waters while orbiting around the south side of the upper vortex. The model consensus has also shifted northward with the track of the surface low such that the surface low would most likely spend too short of a time over warm Gulf Stream waters to have tropical characteristics. Therefore at this time not adding an area of interest for this forecast surface low.
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z (Jun 20) CMC Model Run...
**Current east Canada to NW Atlantic upper trough deposits upper vortex offshore of the eastern US at 48 hours… split flow upper divergence between the west side of the vortex and east side of the current US deep-layer ridge creates a broad surface low across North Carolina at 60 hours… east end of the surface low becomes a possible tropical cyclone offshore of the North Carolina Outer Banks near 34N-72.8W at 72 hours… tropical cyclone soon after loses tropical characteristics and weakens while turning east and then north into cooler waters while orbiting the south side of the upper vortex… the remnant non-tropical low reaches 40N-66.5W at 120 hours
1200Z (Jun 20) ECMWF Model Run.…
** Current east Canada to NW Atlantic upper trough deposits upper vortex offshore of the eastern US at 48 hours…split flow upper divergence between the west side of the vortex and east side of the current US deep-layer ridge drops surface pressures across Virginia and the Carolinas during this time… after a sprawling low pressure area develops a tight circulation in the low pressure area forms offshore of the US east coast near 34.8N-71.5W at 72 hours… tight circulation accelerates northeast to 42N-66.5W at 120 hours
1800Z (Jun 20) GFS Model Run...
** Current east Canada to NW Atlantic upper trough deposits upper vortex offshore of the eastern US at 48 hours…split flow upper divergence between the west side of the vortex and east side of the current US deep-layer ridge generates broad surface low pressure across the Carolinas and Virginia by 54 hours… east end of the broad low pressure develops a tighter center offshore of the eastern US at 69 hours near 36.5N-72W… while moving northeast weakens to a surface trough offshore of the northeast US by 120 hours.
**Surface low becomes defined in the southern Caribbean Sea near 12N-79W at 141 hours… develops into a possible tropical cyclone just east of Nicaragua by 168 hours
1200Z (Jun 20) NAVGEM Model Run...
**No tropical cyclone formation shown in the Atlantic basin over next 168 hours (7 days)