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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 

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*******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 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 dot gov) for the latest watches/warnings and official forecasts on active tropical cyclones.**********

...TUESDAY AUGUST 1 2023 11:55 PM EDT...

See area of interest #17 section below for more information on a tropical low pressure in the open central tropical Atlantic that continues to be monitored for signs of development for the days ahead.

Elsewhere... satellite imagery shows a tropical wave of low pressure has recently emerged from western Africa and into the eastern tropical Atlantic with concentrated thunderstorm activity. Atmospheric conditions will likely be conducive for its development due to an expansive tropical upper ridge in the region... featuring low shear and upper outflow... which is forecast to persist. Should the tropical wave continue to wall off the dry Saharan air layer to the north with ongoing thunderstorms... and/or should the tropical wave gains computer model support... will add it as an area of interest in future updates.

AREA OF INTEREST #17... The tropical low pressure in the open central Atlantic is continuing northwestward in the flow on the southwest side of the Atlantic surface ridge... and will soon curve north and then eventually northeastward into the open north Atlantic as it moves into the surface ridge weakness associated with the cold front currently in the western Atlantic. The tropical low pressure is south and west of the previous forecast track... and the updated track shown is adjusted accordingly. The thunderstorm activity continues to be displaced to the east thanks to westerly shear being generated by the south side of the current central Atlantic upper vorticity string. In the next 24 hours the upper-level winds will become more conducive for development as the shearing cool core upper vorticity is forecast to dissipate due to prolonged isolation from high-latitude cold air. Regarding odds of development... initially I was inclined to raise peak odds above 40% as a better defined cloud swirl was developing near the thunderstorm activity. However in recent hours the activity has waned... and the adjusted forecast track is also now closer to the cold front which means it could merge with the front and hence lose tropical characteristics sooner. This is why by 48 hours I already lower development odds below the 40% peak. I drop odds of tropcial cyclone development to 0% by 72 hours as this system finishes merging with the cold front... moves into cooler waters... and aligns with the supportive eastern divergence zone of the upper trough currently approaching from eastern Canada... which should transition this system into a non-tropical frontal cyclone supported by the upper trough.

By early Friday this system is expected to be passing offshore of southeastern Newfoundland... most likely while transitioning into a remnant frontal cyclone as discussed above. The remnant cyclone may produce surf that reaches the shores of Newfoundland during this timeframe.

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

IOH 24 Hr Outlook (0000Z Aug 3)... 40% chance of tropical cyclone formation (central Atlantic near 32N-57W)

IOH 48 Hr Outlook (0000Z Aug 4)... 30% chance of tropical cyclone formation (central Atlantic near 39N-54.5W)

IOH 72 Hr Outlook (0000Z Aug 5)... 0% chance of tropical cyclone formation (north Atlantic near 46N-46W)

******National Hurricane Center ( official outlook as of 8 PM EDT*****************************

Formation chance through 48 hours...20%

Formation chance through 7 days (168 hours)...20%


Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (

1200Z (Aug 1) CMC Model Run...

**For area of interest #17... no development shown

**Tropical wave currently on the west coast of Africa becomes a compact tropical low near 13.8N-49.5W at 150 hours... tropical cyclone formation suggested shortly thereafter with the cyclone reaching 15.5N-44.5W at 168 hours

1200Z (Aug 1) ECMWF Model Run...

**For area of interest #17... no development shown

1800Z (Aug 1) GFS Model Run...

**For area of interest #17... no development shown

1200Z (Aug 1) NAVGEM Model Run...

**For area of interest #17... no development shown

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