MY 2023 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #4
*******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.**********
...THURSDAY JANUARY 26 2023 6:38 AM EDT...
Eastern Atlantic surface low pressure becoming a broad system without a well-defined center due to an area of widespread upper divergence... see area of interest #1 section below for more information. Therefore the potential for the eastern Atlantic surface low pressure to become a subtropical cyclone has ended and as such I will be ending regularly-scheduled birdseye view post on the Atlantic tropics. Will resume daily posts on the Atlantic tropics at the start of the hurricane season on June 1... or unless the potential for subtropical or tropical development returns to the Atlantic basin before then.
As done on this site starting last year... I will be sequentially numbering up areas of interest for possible Atlantic tropical development throughout the year... resetting back to #1 at the start of each year. This scheme is so that each area of interest retains a numeric identity from update to update... which reduces confusion when simultaneous areas of interest begin and end when tropical activity increases particularly during the Atlanitc Hurricane Season. I have not counted the short-lived northwest Atlantic tropical event on January 16 as #1 as that system was expected to quickly shed its tropical characteristics and not become identified as a subtropical or tropical cyclone by the National Hurricane Center... instead I am identifying the area of interest discussed below as #1 for this year (refer to special update #0A available on the home page of this site for a report on the January 16th event).
AREA OF INTEREST #1... The eastern Atlantic surface low pressure is becoming disrupted by the arrival of an upper vortex from the northwest... which has materialized due to the re-amplifying western Atlantic upper ridge which has amplified the south part of the current northwest Atlantic upper trough into a vortex (note the western Atlantic warm core upper ridge re-amplified due to warm southerly flow ahead of the vigorous eastern US winter storm underway as of this writing). The parent upper vortex that originally generated the surface low pressure is producing upper divergence to the east... while the second upper vortex which arrived from the northwest is being disruptive by producing another area of upper divergence to the west. The combination of both upper divergence zones is producing a sprawling area of lowering surface pressures that the original well-defined center of the surface low pressure (located near 24N-36W as of 0600Z) is losing its identity within... and this original center is not showing signs of acuqiring tropical characteristics while lacking thunderstorm activity that would have otherwise maintained it through tropical processes (i.e. becoming aided warm core outflow generated by thunderstorm latent heat release).
The remnant sprawling broad surface low pressure area is expected to shift westward going forward while steered by the merger between the re-amplifying western Atlantic upper ridge and current northeast Atlantic deep-layer ridge. The upper layer of the steering deep-layer ridge is forecast to be southwest of the surface layer... resulting in a faster westward track of the surface low pressure area while the overhead upper vorticity in the region lags behind toward the east. This will eventually place the surface low pressure area underneath suppressive upper convergence on the west side of the upper vorticity... ultimately weakening the surface low pressure area with time.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0600Z Jan 27)... 0% chance of subtropical cyclone formation (central Atlantic near 24N-40W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
0000Z (Jan 26) CMC Model Run...
**For area of interest #1... broad surface low pressure shifts west and weakens to a surface trough near 21N-46W by 72 hours.
0000Z (Jan 26) ECMWF Model Run...
**For area of interest #1... broad surface low pressure shifts west and weakens to a surface trough near 25N-45W by 60 hours.
0000Z (Jan 26) GFS Model Run...
**For area of interest #1... broad surface low pressure shifts west and weakens to a surface trough near 25N-46W by 66 hours.
0000Z (Jan 26) NAVGEM Model Run...
**For area of interest #1... broad surface low pressure shifts west and weakens to a surface trough near 23N-46W by 60 hours