MY 2023 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #4A (Special Update)
*******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 JANUARY 27 2023 10:22 AM EDT...
The following is a special update on the eastern Atlantic surface low pressure area tagged as area of interest #1 in full update #4... which has recently moved westward into the central Atlantic while seeing an increase in shower and thunderstorm activity. Satellite image of this disturbance at the time of this writing (1430Z) is provided below:
The eastern Atlantic surface low pressure area... which was broadening due to the added region of upper divergence incoming from the northwest associated with a second upper vortex in addition to the divergence zone of the first parent upper vortex that initially generated this system... has seen an increase in shower and thunderstorm activity over the last several hours while continuing westward into the central Atlantic. As of 0600Z the NHC TAFB surface analysis placed the broad center of circulation at 22.5N-42.5W which on an ASCAT-B or ASCAT-C satellite pass presents itself as a southwest-northeast elongated and sprawling system (https://manati.star.nesdis.noaa.gov/datasets/ASCATData.php). Toward the northeast side of the elongated circulation... near 25N-40W... the shower and thunderstorm activity presents itself in an organized hook or comma shape. Despite water temps in the region being at 23 deg C... the increase in shower and thunderstorm activity is likely attributed to the divergence zone of the incoming second upper vortex and also the de-stabilzing cold temperatures of this vortex (200 mb heights of 1190 dekameters). This system is likely not being mentioned in the NHC tropical weather outlook due to the lack of a well-defined center within the elongated broad surface circulation. Should this situation later change... particularly if a well-defind surface center develops close to/within the thunderstorm activity... will resume regularly-scheduled posts on this system. Otherwise...regularly-scheduled posts will resume at the start of the Atlantic Hurricane Season on June 1st... or if another subtropical/tropical system of interest develops before then.
Final note... due to the upper layer of the steering deep-layer ridge being further southwest relative to the surface layer... the surface low pressure area will continue faster to the west than the overhead upper vorticity... placing the surface low pressure area underneath the suppressive western convergence zone of the upper vorticity over the next day or so which should weaken the thunderstorm activity and surface low pressure area.