cieldumort
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An overwhelming majority of all models and their ensembles are now forecasting the development of a strong or very strong non-tropical low near or over the Gulf Stream roughly east of North Carolina as soon as late Sunday. This region is now an official 20% Area of Interest and given its potential to transition into a strong subtropical or even tropical cyclone and have significant coastal impacts regardless, we are starting a Lounge on this feature at this time, Invest TBD.

Above: Water Vapor image of precursor system 10-17-26-2225z. SST contours added. Image credit: Weathernerds.org
2026-10-19 18:00 33.8N 70.6W 45KTS
During the day on October 19, 2026, the non-tropical low pressure system we have been tracking was Invest-tagged, 93L, and the title has been updated accordingly.
Ciel
2026-10-21 18:00 37.1N 69.6W 55KTS
During the day on October 21, 2026, Invest 93L was found to have completed transition into a strong sub-tropical cyclone, and Advisories have begun on Josephine. The title has been updated accordingly.
Ciel
Edited by cieldumort (Wed Oct 21 2026 05:34 PM)
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cieldumort
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Today's most recent DeepMind FNv3 1000-member ensemble advertising a 61% chance of reaching 34+ knots

Image credit: TC-ATLAS
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cieldumort
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cieldumort
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93L 10-20-26-05z MSLP 850 hPa Vorticity SST analysis overlay atop IR. Image credits: TC-ATLAS
The cyclone is trying, but relatively cool SSTs as well as some shear are clearly challenging the attempted transition, so far
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cieldumort
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That 'little bit of shear'

Credit: CIMSS
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cieldumort
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Invest 93L appears to be rapidly transitioning into a tropical storm tonight and it would not be surprising to see Josephine declared tomorrow morning, if not sooner. Virtually all models and ensembles take it well out to sea.
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cieldumort
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Some 10-21-0z runs from hurricane and regional models (three of each) for 10-22-0z





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cieldumort
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10-21-0z DeepMind FNv3 1000-member ensemble now at 98% development odds. Out to sea.
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