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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 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 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.**********

...SATURDAY SEPTEMBER 28 2019 11:49 AM EDT...

See Karen and Lorenzo sections below for all active tropical cyclones in the Atlantic basin. Elswhere over the next week...a broad area of low pressure is expected to develop over the western Atlantic...western Caribbean...and southeastern Gulf of Mexico as a pattern of upper divergence persists between the east side of the upper trough currently in the western Atlantic and the cell of upper ridging in the western tropical Atlantic. Will watch to see if a tropical disturbance emerges within this broad low pressure area. Meanwhile...the favorable upward motion of the Madden Julian Oscillation (MJO) is beginning to shift east...and could leave the Atlantic basin next week which would reduce the overall tropical activity in the Atlantic (

REMNANTS OF KAREN...Looks like Karen continues to be entangled with the remnant low pressure of Jerry at a location southeast of Bermuda...and appears will soon be absorbing the remnant of Jerry. This entanglement has kept Karen at a more northeast position into dry air caused by upper convergence on the southwest side of the upper trough ejecting from eastern Canada and northwest Atlantic..and dry air caused by convergence between the northeast side of the cell of upper ridging in the area and west side of the central Atlantic upper trough to the east. The result is Karen has degenerated into a remnant low pressure absent of thunderstorms. Regeneration into a tropical cyclone is not expected as the remnant low drifts westward under the influnce of the surface ridge moving into the western Atlatnic...with Karen's more north than previously forecast positions keeping the remnant under unfavorable westerly shear on the north side of the cell of tropical upper ridging...followed by westerly shear from the upper trough in the western Atlantic that will approach from the west. The remnant low should lose its identity to a broad surface trough of low pressure to consolidate to the be supported by a large area of upper divergence between the west side of the cell of upper ridging and east side of the upper trough. This is my final statement on Karen on this blog as it is no longer a tropical cyclone.

MAJOR HURRICANE LORENZO...Lorenzo has weakened to a minimal but still formidable category 3 hurricane in the last 24 hours while sheared by the upper trough in the central Atlantic...but as well-forecast in the modeling its latent heat release has split the cold core upper trough in half...with the thunderstorms becoming better organized and more symmetric about the eye while the hurricane is in a lower shear spot between the split halves of the upper trough this morning. My intensity forecast is adjusted downward in the short term to account for the recent weakening...but does catch up to my previous one as I forecast Lorenzo to re-strengthen in the lower shear environment in the next 24 hours...and keep strength by 48 hours as its tremendous latent heat release keeps a portion of the unfavorable upper trough ejecting from eastern Canada/NW Atlantic cut-off and at bay to the west. The smidge of weakening I show at 48 hours has a little to do with some light shear out ahead of the aforementioned upper trough ejecting from eastern Canada/NW Atlantic...but has more to do with increasingly cooler water temps along the forecast track because as mentioned prior the thunderstorm latent heat release appears enough to keep the effects of the upper trough minimized. The upper southwesterly flow ahead of the aforementioned upper trough will try to nudge Lorenzo eastward...but the Atlantic subtropical surface ridge will prevent an eastward turn for the early part of the forecast. Once Lorenzo moves past the surface ridge by 72+ will finally turn increasingly eastward toward the Azores. As it does so...a second a more vigorous upper trough ejecting from the central Canada upper vortex will keep Lorenzo energized with tremendous upper divergence on its east side...thus transitioning Lorenzo into a formidable non-tropical remnant gale still packing hurricane-force winds. Therefore it appears damaging winds will overspread the Azores on Tuesdsay evening...interests here should continue to monitor the progress of Lorenzo carefully and begin preparations for the wind and coastal sea swells tomorrow! My updated forecast track is once again nudged westward given Lorenzo's current position...and it appears the most significant effects from Lorenzo in the Azores will be towards the western islands.

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

0 Hr Position (1200Z Sep 28)...115 mph maximum sustained major hurricane centered at 22.5N-44.8W

IOH 24 Hr Forecast (1200Z Sep 29)...125 mph maximum sustained wind major hurricane centered at 27N-43.5W

IOH 48 Hr Forecast (1200Z Sep 30)...120 mph maximum sustained wind major hurricane centered at 31N-42W

IOH 72 Hr Forecast (1200Z Oct 1)...105 mph maximum sustained wind hurricane transitioning to non-tropical centered southwest of the Azores at 35N-37.5W

IOH 96 Hr Forecast (1200Z Oct 2)...95 mph maximum sustained wind non-tropical remnant gale centered north of the Azores at 46.5N-26W

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