BIRDSEYE VIEW POSTS

Since 2012 on the Weather Underground (www.wunderground.com) 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 via Disqus on Weather Underground at www.wunderground.com/cat6. You can see my Disqus feed at this link for my latest comments. Feel free to reply to me with your disqus account or e-mail at IOHurricanes@outlook.com 

 
 
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MY 2020 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #129

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


...WEDNESDAY SEPTEMBER 23 2020 11:50 AM EDT...

See remnants of Paulette...remnants of Teddy...and remnants of Beta sections below for a final statement on all three systems. See area of interest section below for the tail end of a cold front moving into Cuba that was previosuly being monitored for tropical development.


REMNANTS OF TEDDY...While remaining supported by the tremendous upper divergence zone of a large upper trough to the west...which is the merger of an upper trough over central North America and a more amplified trough over the western Atlantic which Teddy previously amplified with its western cold air advection (southward cold air transport)...Teddy is still packing a large area of strong winds after transitioning to a remnant frontal cyclone that is now moving into Atlantic Canada. As such...interests in Nova Scotia...Prince Edward Island...New Brunswick...and Newfoundland should be hunkered down until the winds and coastal waves of Teddy pass. By tomorrow the remnant frontal cyclone will be in the far north Atlantic waters between eastern Canada and western Greenland where it will kick up high waves...with coastal sea swells expected for the east Canada and western Greenland shores until the remnant frontal cyclone of Teddy fades as a typical post-mature frontal cyclone that whirls beneath its supporting upper trough axis where there is less upper divergence. This is my final statement on Teddy on this blog as it is no longer a tropical cyclone...but the home page bulletins on this site will continue to carry statements on the remnants of Teddy as long as they continue to bring impacts.


REMNANTS OF BETA...Slow-moving tropical depression Beta has transitioned into a remnant non tropical low pressure supported by the eastern divergence zone of an incoming upper trough from the southwestern United States. The reason for the ongoing slow eastward slow motion is both the slow motion of the supporting upper trough and also the blocking effect of a strong surface ridge that remains parked over the central and eastern United States. The center of Beta's remnant low is just northeast of the Houston/Galveston Bay area of Texas based on the latest doppler radar imagery. The heavier rain has shifted into Louisiana where flash flood watches remain in effect due to the potential for long periods of heavy rain as Beta continues to move slowly... so when encountering a flooded roadway...do not drive into the floodwater to avoid accidental drowning! Because the divergence maximum of the upper trough is currently north of Beta...rainfall extends further north along the Mississippi river valley in areas such as eastern Arkansas...western Mississippi...and western Tennessee...and a flash flood watch has been extended into western Mississippi. After 48 hours...the remnant of Beta is expected to dissipate over the Alabama/Mississippi region as the supporting upper trough moves eastward and away while Beta remains trapped by the blocking surface ridge over the eastern United States. This is my final statement on Beta on this blog as it is no longer a trpoical cyclone...but the home page bulletins on this site will continue to carry statements on the remnants of Beta as long as they continue to bring impacts.


REMNANTS OF PAULETTE...Tropical Storm Paulette's continued lack of thunderstorms last night caused its downgrade to a remnant low pressure by the National Hurricane Center...but this morning Paulette has seen some increase in activity as the eastern divergence zone of energy from a northeastern Atlantic upper trough has arrived. However in the next 24 hours Paulette and the upper-level energy will be in two seperate places...with Paulette slowing down and beginning to drift southweswtward under the influence of deep-layered ridging incoming from the west (a surface north Atlantic ridge supported by the eastern convergence zone of a warm north Atlantic upper ridge driven by Teddy's northward warm air transport)...and the upper-level energy splitting into two...one piece retrograding southwestward and away around the deep-layered ridge...and another piece continuing eastward and away into Europe. The loss of upper air support for Paulette's remnant means it will commence weakening by 24 hours and beyond as it moves around the south side of the deep-layered ridge. This is my final statement on Paulette on this blog as it is no longer a tropical cyclone.


AREA OF INTEREST #1....The tail end of a western Atlantic cold front has shifted southward into Cuba (the same front that has merged with Teddy and now being driven by Teddy's remnant cyclone). The non-tropical remnant low pressure of Beta...currently moving into Louisiana...will push the warmest air in the Gulf of Mexico southeastward toward Cuba...resulting in a warm upper ridge directy over the decaying front such that the decaying front might evolve into a tropical disturbance with thunderstorms aided by the outflow of the upper ridge. Anything that develops here will shift northwestward across the eastern Gulf of Mexico around the southwest side of the eastern United States surface ridge. I have lowered odds of tropical cyclone formation here to 0% as no disturbance has formed thus far...and any disturbance that does form only would have a narrow window for additional development as it would quickly enter shearing upper southwesterly winds on the northwest side of the Cuba upper ridge. This is my final statement on this disturbance on this blog as it has also been removed from the National Hurricane Center tropical weather outlook.

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

IOH 24 Hr Outlook (1200Z Sep 24)...0% chance of tropical cyclone formation (southeastern Gulf of Mexico offshore of western Cuba near 24N-84W)


...COMPUTER MODEL SUMMARY...

Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)


0000Z CMC Model Run...For area of interest #1...no tropical cyclone formation shown.


0000Z ECMWF Model Run....For area of interest #1...no tropical cyclone formation shown.


0600Z GFS Model Run...For area of interest #1...no tropical cyclone formation shown.


0600Z NAVGEM Model Run...For area of interest #1...no tropical cyclone formation shown.

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