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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.**********

...SUNDAY JULY 30 2023 2:15 AM EDT...

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

Elsewhere... the tropical wave of low pressure that recently emerged from western Africa and into the eastern tropical Atlantic is ingesting dry Saharan air. In addition... as the current central Atlantic upper vorticity to the north gradually fades from ongoing isolation from high-latitude cold air... it will gradually dissipate which will allow for the tropical Atlantic upper ridge axis to shift north. This may later subject this tropical wave to less favorable easterly shear on the south side of the upper ridge axis instead of allowing the tropical wave to develop in the low shear/outflow environment closer to the upper ridge axis... therefore this tropical wave is not an area of interest for further development.

AREA OF INTEREST #17... The northeast end of the central Atlantic tropical wave of low pressure has seperated from the rest of the wave axis as a now independent tropical low pressure. This tropical low pressure... which continues to be monitored for signs of further development... has accelerated northwestward in the flow between the remainder of the wave axis to the southwest and Atlantic surface ridge to the north. On this track the tropical low pressure has pushed through the dry Saharan air layer which caused it to have a lack of thunderstorms for much of Saturday. However in the most recent hours the thunderstorm activity has increased... particularly in the northern semicircle of the circulation... albeit this activity is not well organized so far.

Looking ahead... the current upper troughing over eastern North America will soon move offshore into the Atlantic where it will induce a surface ridge weakness... and a northward turn into the weakness is anticipated in the longer range. The updated forecast track in my outlook below is nudged northeastward relative to the previous due to the tropical low's current position relative to the previous forecast. Regarding odds of development... I maintain peak odds to 40% instead of going above 50% as the forecast track takes this disturbance into the south side of the central Atlantic upper vorticity thru 72 hours which will likely result in westerly shear. By 96+ hours the cool core upper vorticity is forecast to dissipate due to prolonged isolation from high-latitude cold air... making conditions most favorable for development within the 5-day forecast window assuming the disturbance does not lose too much organization from its interaction with the upper vorticity.

The potential for coastal surf for the northern Lesser Antilles from this disturbance has reduced as the forecast track update keeps this system even further from the islands. In about five days this system could be passing just offshore of southeastern Newfoundland potentially as a tropical cyclone... surf generated by this system could therfore reach the shores of Newfoundland during that timeframe.

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

IOH 24 Hr Outlook (0000Z Jul 31)... 30% chance of tropical cyclone formation (central Atlantic near 21.5N-53W)

IOH 48 Hr Outlook (0000Z Aug 1)... 30% chance of tropical cyclone formation (central Atlantic near 24.5N-55W)

IOH 72 Hr Outlook (0000Z Aug 2)... 30% chance of tropical cyclone formation (central Atlantic near 29.5N-55W)

IOH 96 Hr Outlook (0000Z Aug 3)... 40% chance of tropical cyclone formation (central Atlantic near 34.5N-55W)

IOH 120 Hr Outlook (0000Z Aug 4)... 40% chance of tropical cyclone formation (south of southeastern Newfoundland near 42.5N-51.5W)

******National Hurricane Center ( official outlook as of 2 AM EDT*****************************

Formation chance through 48 hours...40%

Formation chance through 7 days (168 hours)...70%


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

1200Z (Jul 29) CMC Model Run...

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

1200Z (Jul 29) ECMWF Model Run...

**For area of interest #17... compact tropical cyclone formation suggested near 28N-54.5W at 72 hours... the compact tropical cyclone accelerates north-northeast to 41.2N-51W through 120 hours

0000Z (Jul 30) GFS Model Run...

**For area of interest #17... compact tropical cyclone formation suggested near 31N-55W at 84 hours... the compact tropical cyclone accelerates north and then north-northeast to 43.8N-51.5W through 120 hours

1800Z (Jul 29) NAVGEM Model Run...

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

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