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 2021 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #12 (Weekend Edition)

*******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 JUNE 6 2021 2:20 PM EDT...

Satellite image as of 1230Z. Areas of interest circled in yellow are not mentioned in the NHC tropical weather outlook. Areas circled in a green dashed line are in the NHC 5-day tropical weather outlook. Areas circled in a solid green line are in the NHC 2-day tropical weather outlook:

NHC TAFB Surface Analysis 0600Z:

GFS Model Upper-Level Winds 1200Z:

Welcome to what I call my “weekend edition” posts...where I put together the entire post on using only mobile phone tools instead of a laptop computer. This will allow me to execute these posts while on the go during weekend activities.


See area of interest section below regarding the potential tropical development between Bermuda and the northern Caribbean Islands in the coming days. Elsewhere...the latest computer model runs continue suggest that the current Caribbean cold core upper vorticity will remain cut-off from mid-latitude cold air...resulting in its dissipation and replacement by the warm core upper ridging currently over the Gulf of Mexico. The low shear and outflow of the upper ridging will make conditions more conducive for the lowering of surface pressures and tropical development across Central America and the Caribbean. The CMC...GFS...and NAVGEM are on increasing agreement on western Caribbean development in about a week. However...I have not highlighted the western Caribbean Sea at this time to see if the model consensus stays over the next day or so.


AREA OF INTEREST #1...Warm upper ridging is expected to amplify across North America due to surface warm southerly flow forecast on the west side of the Atlantic surface ridge and east side of the current central Canada frontal system...followed by another frontal system to become parked over the western US. This upper ridging will cut-off a part of the current upper trough entering the NW Atlantic into a vortex that dives southeast toward the waters north of the Caribbean Islands and south of Bermuda. The GFS continues to forecast a well-defined surface subtropical or tropical system by days 4 and 5...triggered by the divergence zone of the forecast upper vortex. In the outlook below...a northward track begins by day 5 as a North Atlantic upper trough is forecast to amplify southward and gradually erode the west extent of the Atlantic surface ridge...while driving a frontal cyclone to exit from Atlantic Canada by day 5...and in the long range driving a surface front to eject from the northeast US. Beyond day 5...conditions for tropical development will be less favorable as the north track will take this system to waters below 26 deg C...thus the potential for this system to bring coastal sea swells to Bermuda appears low and is dependent on how much development occurs on days 4 and 5. I have low 20% odds of development as only the GFS forecasts the formation of a well-defined surface feature...and going forward will only raise odds further if other models join or if observations in the coming days warrant.

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

IOH 24 Hr Outlook (1200Z Jun 7)...0% chance of tropical cyclone formation (western Atlantic near 30N-70W)

IOH 48 Hr Outlook (1200Z Jun 8)...0% chance of tropical cyclone formation (western Atlantic near 27.5N-68W)

IOH 72 Hr Outlook (1200Z Jun 9)...0% chance of tropical cyclone formation (western Atlantic near 25N-65W)

IOH 96 Hr Outlook (1200Z Jun 10)...20% chance of tropical cyclone formation (western Atlantic near 25N-62.5W)

IOH 120 Hr Outlook (1200Z Jun 10)...20% chance of tropical cyclone formation (western Atlantic near 27.5N-62.5W)


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