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BIRDSEYE VIEW POSTS

Since 2012 on the now retired Weather Underground blogs, I have been posting annotated "birdseye view" charts of the Atlantic basin, with a detailed explanation and forecasting that references the chart. From there you may know me as "NCHurricane2009." While I now do these "birdseye view" posts here, I will continue to do comments at Yale Climate Connections via Disqus where the former Weather Underground community has moved to. Feel free to reply to me there, at my Disqus feed at this link, or via e-mail at IOHurricanes@outlook.com 

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MY 2024 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #39

*******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 JULY 12 2024 4:45 AM EDT...

See area of interest #11 section below for an update on the broad tropical disturbance offshore of the southeastern United States coast expected to make landfall by late tonight. It is quiet elsewhere in the Atlantic tropics.


AREA OF INTEREST #11... A broad surface low pressure field offshore of the southeastern United States has materialized from the merger between an offshore surface trough that materialized Wednesday and tail end of a surface front attached to ex-Beryl that is moving into offshore waters… and the disturbance remains supported by split flow upper divergence between the west side of the upper vortex approaching from the east and southeast side of the regional upper ridge axis. The overall flow between these two upper features remains northeasterly… and northeasterly shear continues to negatively affect the disturbance. For instance early on Thursday a burst of thunderstorms on the south side of the circulation appeared to be generating a better-defined low-level spin near 30.5N-78W… which at the time was confirmable on the CIMSS 850 mb vorticity product (https://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor&zoom=&time=). However by Thursday evening the burst was pushed off to the west by the shear and collapsed offshore of northeastern Florida… and the 850 mb signature became less consolidated and more elongated north-south. Around 0300Z early this morning a second similar short-lived burst was in progress just north of the northwestern Bahamas which has since fizzled.


Per the latest NHC TAFB surface analysis at 0000Z the lowest pressure of the disturbance may have already shifted onshore onto the Georgia coast and along the aforementioned incoming surface front. However the CIMSS 850 mb vorticity product shows the 850 mb elongated circulation remains offshore… therefore not counting this disturbance down and out yet until the 850 mb layer of the circulation moves west and onshore (the low-level steering pushing the disturbance west is being provided by the surface ridge approaching from the Great Lakes)… especially as the 850 mb layer of the circulation potentially takes advantage of better upper winds directly below the regional upper ridge axis (area of lowest shear and maximal upper outflow) as it makes landfall in the vicinity of coastal Georgia. Noting the suppressing upper vortex to the east is not expected to squash this disturbance at landfall time as the vortex is beginning to turn north and away toward the incoming Great Lakes upper trough. Because the disturbance has not become organized over the last 24 hours and will have little time to do so as it makes landfall… I have lowered my peak odds of tropical cyclone formation to 10%. Regardless of tropical cyclone formation or not... this disturbance has potential to produce periods of heavy rain across Florida… Georgia… and the Carolinas through Saturday… incidents of flash flooding in the region cannot be ruled out.

******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********

IOH 24 Hr Outlook (0000Z Jul 13)... 10% chance of tropical cyclone formation (coastal Georgia near 31.2N-81.2W)

IOH 48 Hr Outlook (0000Z Jul 14)... 0% chance of tropical cyclone formation (southwestern Georgia near 31.8N-84W)

*****National Hurricane Center (hurricanes.gov) official outlook as of 2 AM EDT**************************

Formation chance through 48 hours... 0%

Formation chance through 7 days... 0%


...COMPUTER MODEL SUMMARY...

Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).


1200Z (Jul 11) CMC Model Run...

**For area of interest #11... over next 24 hours broad surface low shifts west toward southeast US coast with northeast part of the circulation developing a better-defined center making landfall on the South Carolina coast... through 48 hours the remainder of the circulation makes landfall and degenerates into a SW/NE tilted surface trough spanning Georgia and the Carolinas… trough dissipates shortly thereafter


1200Z (Jul 11) ECMWF Model Run...

**For area of interest #11... broad surface low makes landfall on vicinity of GA/SC border at 30 hours… dissipates shortly thereafter


1800Z (Jul 11) GFS Model Run...

**For area of interest #11... broad surface low makes landfall on vicinity of GA/SC border at 18 hours… after arriving to west-central Georgia at 36 hours dissipates shortly thereafter


1800Z (Jul 11) NAVGEM Model Run...

**For area of interest #11... broad surface low makes landfall on South Carolina coast at 18 hours… gradually decays into a surface trough covering the Carolinas through 66 hours which proceeds to dissipate shortly thereafter

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