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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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Updated: May 5, 2022

*******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.**********

...WEDNESDAY MAY 4 2022 9:30 PM EDT...

Although Atlantic Hurricane Season does not officially start till June 1st... resuming daily birdseye view posts due to potential subtropical cyclone formation in the western Atlantic in the days ahead. Regardless of whether the forecast cyclone acquires tropical characteristics... it is likely to produce sea swells and rip currents for the mid-Atlantic and northeastern United States coast by this weekend. See area of interest #1 section below for more details.

AREA OF INTEREST #1... An amplified upper trough and associated surface low pressure ejecting eastward from the southwestern US is expected to produce severe thunderstorms across the south-central US through tonight... spreading into the southeastern US over the next 48 hours... check your local and national news media for more info on this severe weather outbreak. Sliding east in tandem with this severe weather system is a current upper trough over eastern Canada.

By Friday a northeastern Pacific upper trough will pivot toward western Canada and support a vigorous surface frontal cyclone... with this cyclone’s warm southerly flow supporting a warm deep-layer ridge over central and eastern Canada. Per the latest computer model consensus... this ridge will in turn cut-off the aforementioned severe weather system and also a portion of the current eastern Canada upper trough into a western Atlantic upper vortex by 72+ hours. The eastern divergence zone of the upper vortex will trigger the formation of a broad surface cyclone... with the models also agreeing on the upper vortex and surface cyclone retrograding west-southwest toward the southeast US coast in 4+ days under the influence of the Canadian deep-layer ridge. By the end of the 5-day forecast period I have low 10% odds of subtropical cyclone formation due to lukewarm low-20 deg C water and an upper vortex not very cold (1200 dekameter height at 200 mb... would like to see heights below 1200 dekameters for more confidence in instability for thunderstorms). It should be noted that as the surface cyclone and upper vortex move west-southwest closer to the warmer Gulf steam waters after day 5... the potential for more instability and higher subtropical development odds is on the table.

A tight surface pressure gradient is expected to setup between the north side of the forecast surface cyclone and south side of the Canadian deep-layer ridge. This will drive a strong toward-shore wind and ocean flow for the northeastern and mid-Atlantic US east coast by this weekend... expect coastal sea swells and rip currents here regardless of whether or not the surface cyclone gets tropical characteristics.

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

IOH 24 Hr Outlook (1800Z May 5)...0% chance of subtropical cyclone formation (Kansas/Oklahoma/Missouri border near 36N-94W)

IOH 48 Hr Outlook (1800Z May 6)...0% chance of subtropical cyclone formation (Kentucky/Tennessee border near 36N-85W)

IOH 72 Hr Outlook (1800Z May 7)...0% chance of subtropical cyclone formation (Offshore of North Carolina/Virginia border near 36N-75W)

IOH 96 Hr Outlook (1800Z May 8)...0% chance of subtropical cyclone formation (western Atlantic near 35N-70W)

IOH 120 Hr Outlook (1800Z May 9)...10% chance of subtropical cyclone formation (western Atlantic near 33N-70W)


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

1200Z CMC Model Run...

**For area of interest #1...broad surface low pressure forecast near 35N-69W by 120 hours

1200Z ECMWF Model Run...

**For area of interest #1...broad surface low pressure forecast near 35N-71W by 120 hours

1200Z GFS Model Run...

**For area of interest #1...broad surface low pressure forecast near 33N-71W by 120 hours

1200Z NAVGEM Model Run...

**For area of interest #1...broad surface low pressure forecast near 33N-72.5W by 120 hours

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