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 #60

*******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.**********


...SUNDAY JULY 12 2020 6:09 PM EDT...

See area of interest section below for an area I am monitoring for tropical development. Elsewhere...the north end of a tropical wave moving through the eastern Caribbean Sea is interacting with the eastern divergence zone of cut-off upper vorticity in the region to produce a cluster of thunderstorms in the western Atlantic northwest of the Dominican Repubilc. Computer models do not show tropical development from this disturbance. It is possible the disturbance will quickly lose activity in the next 24 hours while continuing west-northwest around the southwest quadrant of the Atlantic subtrpoical ridge while moving into unfavorable western convergence on the west side of the upper vorticity. But the GFS model also shows the upper vorticity weakening in the next 24 hours...so this disturbance may also continue to be active a little longer while reaching the waters northeast of the Bahamas in 48 hours...after which time it will encounter unfavorable southwesterly wind shear to be generated by the large upper trough over eastern North America as the trough moves into the west Atlantic. Due to the lack of computer model support and potentially unfavorable upper winds ahead...I have not added this disturbance as an area of interest for tropical development.


AREA OF INTEREST #1...Warm southerly flow on the east side of Fay's remnant frontal low over southeastern Canada has amplified warm upper riding across the western Atlantic...which has caused the shortwave upper trough supporting the surface frontal low pressure that has moved east-southeast into the open central Atlantic to amplify into a cut-off upper vortex now directly overhead of the surface frontal low. Although a clump of showers and thunderstorms has been near the surface frontal low pressure's center...supported by the instability provided by the 23 deg C sea surface temperature in combination with the cold temperatures of the upper vortex...the National Hurricane Center has not considered this activity strong enough to mention this system in their tropical weather outlook. Going forward...conditions will become less favorable for tropical development as the remnant low pressure of Fay creates a weakness in the Atlantic surface subtropical ridge...which will draw the surface frontal low pressure north-northwest into the northwestern quadrannt of the upper vortex where upper convergence will weaken the surface frontal low. Therefore is my final statement on this disturbance on this blog as it is losing potential to become a subtropical cyclone.

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

IOH 24 Hr Outlook (1800Z Jul 13)...0% chance of subtropical cyclone formation (central Atlantic near 43N-41W)


...COMPUTER MODEL SUMMARY...

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


1200Z CMC Model Run...For area of interest #1...frontal low lifts north-northwest into ridge weakness created by the non-tropical remnant of Fay...dissipating near 46N-44W in 42 hours.


1200Z ECMWF Model Run...For area of interest #1...frontal low lifts north-northwest into ridge weakness created by the non-tropical remnant of Fay...dissipating near 43N-41W just after 24 hours.


1200Z GFS Model Run...For area of interest #1...frontal low lifts north-northwest into ridge weakness created by the non-tropical remnant of Fay...dissipating near 45N-42W in 36 hours.


1200Z NAVGEM Model Run...For area of interest #1...frontal low lifts north-northwest into ridge weakness created by the non-tropical remnant of Fay...dissipating near 43N-42W in 30 hours.

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