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 #168

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


...MONDAY NOVEMBER 2 2020 11:00 AM EDT...

See Hurricane Eta section below for the only active tropical cyclone in the Atlantic basin.


Colorized infrared satellite image of Hurricane Eta as of 1540Z showing a pinhole eye in progress:

HURRICANE ETA...Our latest tropical storm of the 2020 Atlantic Hurricane Season...Eta...has become yet another rapidly intensifying hurricane throughout the morning hours while developing a pinhole eye on colorized infrared satellite surrounded by a core of strong thunderstorms...with maximum sustained winds vautling upward to 110 mph that now make the hurricane already a top-end category 2. Given these observations...warm 28 deg C southern Caribbean waters...and symmetric upper outflow channels underneath the upper ridge prevailing across the Caribbean...it is now quiet likely Eta becomes a top-end category 4 hurricane before it makes landfall on the north Nicaragua coast...or possibly the Nicaragua/Honduras border...in the next 24 hours. My 24 hour forecast intensity of 130 mph (minimal category 4) reflects weakening from a top-end category 4 (150 to 155 mph) just after landfall. Forecast track points below have been adjusted to northward as Eta has not bent southward in track just yet in response to the strong surface ridge over the central United States...but it has at least slowed down as expected in response to the ridge. The latest satellite animation seems to suggest some southward angle is beginnign to occur in the track...but more satellite frames will be needed to discern whether this is short-term wobbling of the eye or indeed the start of a longer term trend in the forecast track.


There continues to be indications in multiple model runs over the last few days that Eta will slow down to a potential stall after landfall...and then reverse on a north or northeast track back over water and reform or hang on as a tropical cyclone. It appears this could happen as the current eastern North America upper trough leaves behind a cut-off trough in the vicinity of Florida in a couple of days or so...to be re-enforced by the current upper vorticity on the coast of California as that vorticity later slides eastward into the southeast US. This cut-off upper trough’s eastern divergence zone is forecast to lower surface pressures to the southeast of the blocking central US surface ridge and to the northeast of Eta...with this low pressure field potentially drawing Eta or its remnants back northeastward instead of allowing Eta to continue southwest around the surface ridge. The ECMWF has joined the GFS and CMC in showing Eta lifting back into the western Caribbean water and regenerating into a tropical cyclone in the long term...while the NAVGEM has moved away from the GFS-CMC idea and shows Eta's remnant low dissipating inland...with the northern lobe of Eta's remnant low regenerating into a seperate tropical cyclone under the supportive divergence zone of the cut-off upper trough. Given that the ECMWF is more reliable than the NAVGEM in regards to tropical cyclones...I have now extended my forecast thru 5 days to track what will be the remnant low of Eta...in preparation for issuing probability outlooks on the remnants of Eta once Eta weakens to a remnant low after landfall. I forecast a slow westward drift of Eta's remnant low thru 96 hours as Eta rounds the south side of the central US surface ridge while the surface low pressure field to the northeast slows its progress around the ridge. I wait till 120 hours to lift the remnant low pressure toward the surface low pressure field as this is when the cut-off upper troughing generating the surface low pressure field will get a notable boost from the energy to arrive from the California coast.


Interests in eastern Nicaragua and eastern Honduras should be rushing preparations to completion for potentially catastrophic wind damage and coastal storm surge as Eta is likely to become a top end category 4 hurricane before landfall. Conditions will detereorate by tonight. Severe rainfall flooding is a possibility across all of Nicaragua and Honduras with the potential slow down in the track after landfall as discussed in the previous paragraph.

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

0 Hr Position (1200Z Nov 2)...110 mph maximum sustained wind hurricane centered offshore of Nicaragua and Honduras at 14.8N-81.5W

IOH 24 Hr Forecast (1200Z Nov 3)...130 mph maximum sustained wind major hurricane centered just south of the Nicaragua/Honduras border and just inland from the coast at 14.5N-84W

IOH 48 Hr Forecast (1200Z Nov 4)...Remnant low pressure centered over the Nicaragua/Honduras border at 14N-85W

IOH 72 Hr Forecast (1200Z Nov 5)...Remnant low pressure centered over southern Honduras at 14N-87W

IOH 96 Hr Forecast (1200Z Nov 6)...Remnant low pressure centered over the Honduras/El Salvador border at 14N-89W

IOH 120 Hr Forecast (1200Z Nov 7)...Remnant low pressure centered over the northwest coast of Honduras at 15.5N-89W


...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 Hurricane Eta...makes landfall on north coast of Nicaragua at 42 hours...weakens to a remnant low over central Honduras at 72 hours...remnant low moves northwest toward the east coast of the Yucatan peninsula by 120 hours...in long range remnant low lifts northeastward into the southeastern Gulf of Mexico with possible reformation into a tropical cyclone.


0000Z ECMWF Model Run...For Hurricane Eta...makes landfall on north coast of Nicaragua at 48 hours...weakens to a remnant low over the central Nicaragua/Honduras border by 72 hours...remnant low lifts northwestward across Honduras and into the western Caribbean Sea to the east of Belize at 120 hours...while drifting east-northeast across the western Caribbean Sea in the long range redevelops into a tropical cyclone.


0600Z GFS Model Run...For Hurricane Eta...makes landfall on north coast of Nicaragua at 30 hours...while stationary near the coast weakens to a tropical storm thru 54 hours...weakens further to a remnant low while moving inland across eastern Honduras and reaches north Honduras coast at 72 hours...in long range remnant low lifts northeastward into western Caribbean Sea where regeneration into a tropical cyclone is suggested.


0600Z NAVGEM Model Run...For Hurricane Eta...makes landfall on north coast of Nicaragua at 24 hours...drifts west-southwest while weakening to a remnant low pressure over northwestern Nicaragua at 54 hours. Elsewhere...northern portion of Eta's remnant low pressure field drifts northward from Honduas and into the western Caribbean Sea...and becomes a tropical cyclone at 108 hours...while strengthening the tropical cyclone lifts northeastward toward the Cayman Islands and Cuba.

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