BIRDSEYE VIEW POSTS

Since 2012 on the Weather Underground (www.wunderground.com) 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 via Disqus on Weather Underground at www.wunderground.com/cat6. You can see my Disqus feed at this link for my latest comments. Feel free to reply to me with your disqus account or e-mail at IOHurricanes@outlook.com 

 
 
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MY 2020 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #33

*******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 15 2020 1:44 PM EDT...


See area of interest section below for complex disturbance emerging from the northwestern Caribbean Sea to the waters offshore of the southeastern United States as a tropical wave and old frontal boundaries in the region interact with a longwave upper trough over eastern North America.

AREA OF INTEREST #1...A tropical wave of low pressure that has entered and is crossing the western Caribbean Sea is combining with old surface frontal boundaries to the north and the upper divergence zone on the east side of the longwave upper trough over eastern North America to produce a long band of showers and thunderstorms over the western Caribbean and Bahamas region...extending to the eastern Carolinas and southeastern Virginia. Based on the latest model runs...this complex and elongated disturbance is likely to soon consolidate as a surface trough of low pressure offshore of the southeastern United States...and satellite imagery suggests this maybe already occurring offshore of the Carolinas where the clouds are already hooking around an elongated spin. My updated outlook forecast points below are shifted northward to better align with the timing of the surface trough formation shown in the models...with the paradigm in the outlook being that a pertubation of low pressure will lift northward from the tropical wave...move across the Cuba and the western Bahamas...and into the surface trough offshore of the southeastern United States. It is possible that the tropical wave may not become an important player in this setup...and I may have to more abruptly adjust the area of interest further northward should something organize sooner offshore of the southeastern United States. Whether or not a tropical cyclone forms will be heavily influenced by the evolution of the longwave upper trough over eastern North America...which the models show the south half of evolving into an upper vortex cut-off from the rest of the trough by a pattern of longwave upper ridging building over the central United States. The precise shape and evolution of the cut-off upper vortex will be influenced by the warm air advection zones of frontal systems that will sweep across the western and north-central United States...which will influence of the precise evolution of the adjacent central United States upper ridge. The latest GFS model run suggests an elongated southwest-northeast upper vortex through 72 hours which would produce southwesterly wind shear unfavorable to tropical cyclone development across the region. The shear may relax a bit and supportive upper divergence on the east side of the upper vortex may increase a bit by 96 hours when the GFS shows the upper vortex taking a more north-south shape...so this is when I finally show odds of development above 0%...but I only have a very low 5% odds due to the overall lackluster computer model support. I drop the odds of development back down to 0% as the northeastern quadrant of the upper vortex has potential to hook this system northward into the mid-Atlantic coast of the Uinted States where water temps are too cool to support tropical development.

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

IOH 24 Hr Outlook (1200Z Jun 16)...0% chance of tropical cyclone formation (central Cuba near 22.5N-79W)

IOH 48 Hr Outlook (1200Z Jun 17)...0% chance of tropical cyclone formation (western Bahamas near 26N-78W)

IOH 72 Hr Outlook (1200Z Jun 18)...0% chance of tropical cyclone formation (east of the Florida/Georgia border near 30N-77.5W)

IOH 96 Hr Outlook (1200Z Jun 19)...5% chance of tropical cyclone formation (just south of Cape Hatteras North Carolina near 34N-75.5W)

IOH 120 Hr Outlook (1200Z Jun 20)...0% chance of tropical cyclone formation (southeast coast of Maryland near 37.5N-75.5W)


...COMPUTER MODEL SUMMARY...

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


0000Z CMC Model Run...For area of interest #1...no tropical cyclone formation shown...but a surface low pressure shown to form just offshore of northeast Florida in 30 hours...reaching Cape Hatteras North Carolina by 72 hours...weakens to a surface trough offshore of New Jersey by 108 hours.


0000Z ECMWF Model Run...For area of interest #1...no tropical cyclone formation shown...but a surface trough is shown by 24 hours stretching from southwest Florida to the waters offshore of the Carolinas...develops a low pressure center on the Carolina coast by 48 hours...moves inland into the Carolinas at 72 and 96 hours while weakening to a surface trough...trough dissipated at 120 hours.


0600Z GFS Model Run...For area of interest #1...no tropical cyclone formation shown...but a surface trough of low pressure defined offshore of the southeastern United States by 24 hours...weak surface low defined just offshore of the Carolinas by 48 hours...moves inland into northeastern North Carolina and southeastern Virginia by 90 hours...dissipated inland over Virginia by 108 hours.


0000Z NAVGEM Model Run...For area of interest #1...no tropical cyclone formation shown...but a surface trough shown offshore of the southeastern United States by 48 hours...moves north-northwestward onto the east coast of the mid-Atlantic United States by 102 hours where it dissipates.

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