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 2021 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #4A (Special Update)

*******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 MAY 23 2021 1:01 AM EDT...


Subtropical Storm Ana develops a persisting small core of stronger thunderstorm activity...this special update is to increase the intensity forecast over my previous full update on the Atlantic tropics to indicate the possibility of Ana strengthening further in the next 12 hours. This development could be due to Ana mixing out the dry air that previously prevented it from taking advantage of the de-stabilizing cold upper air temps. I have also nudged the forecast points slightly north and east due to the current position and heading seen in satellite animation.


In this forecast...I have not indicated Ana transitioning to fully tropical status as I am uncertain if the current bout of thunderstorms will last long enough to generate warm core upper outflow...but it wouldn’t surprise me if Ana did so as we have seen other examples of storms gain full tropical status above similar low-20 deg C water temps and cold upper air temps (200 mb heights below 1200 dekameters). It also wouldn’t surprise me if Ana’s actual peak strength ends up being a margin higher or lower than what I forecasted below as small storms such as Ana are notorious for rapid intensity fluctuations (it only takes a small change in central pressure to notably change the pressure gradient between the center and outer edge of the storm...and hence the wind speed...since the distance between the center and outer edge is so small).


For Bermuda...expect any coastal sea swells being generated by Ana to gradually subside as the storm continues pulling away to the east-northeast.

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

0 Hr Position (0000Z May 23)...45 mph maximum sustained wind subtropical storm centered northeast of Bermuda at 35N-61.4W

IOH 12 Hr Forecast (1200Z May 23)...60 mph maximum sustained wind subtropical storm centered at 36N-60W

IOH 36 Hr Forecast (1200Z May 24)...Absorbed by cold front near 37N-55W

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