*******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.**********
...UPDATE...MONDAY JANUARY 24 2022 10:19 AM EDT...
Updated satellite image of subtropical disturbance in the open eastern Atlantic Ocean supported by the upper trough in the region now amplifying into a cut-off upper vortex...taken at 1410Z:
As mentioned in the Saturday update below...a surface low pressure is in the process of forming in the open eastern Atlantic with the support of the eastern divergence zone of the upper trough in the region...which is now amplifying into a cut-off upper vortex. The 0600Z NHC TAFB surface analysis shows a surface trough on the southwest edge of the comma-shaped cloud shield of this disturbance...located in the vicinity of 22.5N-32.5W...and the surface trough is likely to evolve into a surface low pressure spin. While the 0000Z CMC and 0600Z GFS model runs from early today suggested a quick ramp up in the intensity of the surface low...the current surface trough shows no signs of a surface low pressure spin in the low-level cloud field on satellite animation. And with the surface trough/low forecast to soon accelerate westward under the influence of the surface layer of the deep-layered ridge to the north...it is more likely that the surface low will be under the west side of the upper vortex (where suppressive upper convergence is likely) by the time it develops a spin...and therefore a weaker surface low pressure spin as shown in the ECMWF and NAVGEM seems more plausible. Therefore subtropical/tropical cyclone formation here is unlikely...and this is my planned final statement on this disturbance on this blog. Will resume daily posts on the Atlantic tropics at the start of the next hurricane season on June 1 2022... or unless the potential for subtropical or tropical development returns to the Atlantic basin before then.
...SATURDAY JANUARY 22 2021 6:14 PM EDT...
Satellite image of a broad area of showers and thunderstorms produced by an upper trough in the open eastern Atlantic Ocean…taken as of 2210Z:
A surface low pressure in the open eastern Atlantic Ocean is forecast to form in the next couple of days with the support of an upper trough in the region… short window of time for this feature to acquire tropical characteristics as follows:
A warm deep-layered ridge is expected to develop in the central Atlantic with the support of warm southerly flow ahead of a developing surface frontal cyclone currently offshore of the eastern US (the same frontal system that dropped snow and freezing rain across the eastern Carolinas and southeast Virginia last evening). This warm deep-layer ridge will cut-off the south part of the cold core eastern Atlantic upper trough into a cut-off upper vortex over the next 48 hours. During this time models are unanimous in forecasting the formation of an eastern Atlantic surface low pressure supported by the eastern divergence zone of the vortex… with the surface low subsequently accelerating west under the steering influence of the surface layer of the deep-layer ridge.
The westward forecast track of the surface low takes it across 23 deg C waters… which is below the typical 26 deg C threshold needed for tropical development. However the eastern divergence zone of the upper vortex and also cold temps of the upper vortex (forecast by the GFS to be 1200 dekameters in height at 200 mb) may allow the surface low to have thunderstorm activity in the 48 to 60 hour window… and the 06Z and 12Z GFS runs suggested a compact… circular… and stronger core to the surface low pressure field… making it suspect as a possible tropical feature. While the other global models (NAVGEM… ECMWF… and CMC) agree with the surface low’s formation… they did not show as strong of a surface low. In addition… given the narrow window of time for the surface low to acquire tropical characteristics (which will be brought to an end at 60+ hours once the surface low migrates to the west side of the upper vortex where suppressing upper convergence is possible)… I have not opted at this time to begin regularly scheduled posts with probability outlooks for tropical development for this feature.
Will resume daily posts on the Atlantic tropics at the start of the next hurricane season on June 1 2022… or unless the potential for subtropical or tropical development returns to the Atlantic basin before then.