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BIRDSEYE VIEW POSTS

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 IOHurricanes@outlook.com 

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MY 2024 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #116

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

...UPDATE...WEDNESDAY NOVEMBER 13 2024 12:28 PM EDT...

The model data for area of interest #50... which was not previously included in the computer model summary section below to allow for a more timely release of this update... is now included.


...WEDNESDAY NOVEMBER 13 2024 10:00 AM EDT...

Even though it is now mid-November... the Atlantic tropics are flaring back up in activity while monitoring two concurrent areas of interest for possible future development:

(1) High chance of tropical cyclone formation in the Caribbean waters between Central America and the Cayman Islands... see area of interest #49 section below for details.

(2) Some chance of subtropical development in the far eastern Atlantic in the vicinity of the Canary Islands... see area of interest #50 section below for details.


AREA OF INTEREST #49... More recent visible satellite image of the central Caribbean tropical low while positioned south-southeast of Jamaica... as of 1420Z this morning:

Satellite imagery over the last couple of days shows the thunderstorms associated with the broad eastern Caribbean tropical low have been progressively organizing while the system slides into the central Caribbean. Finding a center fix has been challenging as the CIMSS 850 mb vorticity product shows the low-level spin associated with the tropical low has been elongated north-south (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=)... however lately the curvature of the thunderstorm banding suggests the best-defined center is further south along 16.5N latitude in the waters south of Jamaica. The above visible satellite image suggests another swirl center just west of Jamaica... and the CIMSS 850 mb vorticity product shows a flange of low-level spin extending northwest toward that area. Although this system is not quiet a tropical depression due to the ongoing elongated nature of the low-level spin... the models are latching on to the more south overall initial position which keeps it further away from any cool dry air associated with the frontal system that recently moved into the western Atlantic from the central US and also further away from westerly wind shear that develops in the middle of the forecast period... and the models have switched to aggressively developing this area of interest. The latest model trends and increasing organization of this system have caused the NHC to raise odds of tropical cyclone formation to 90% over the last couple of days. Accordingly I have begun a tropical cyclone formation forecast with a specific track and intensity projection now assuming this system will become a tropical cyclone.


A strong surface ridge is building over the eastern US in the wake of the aforementioned frontal system that recently moved into the western Atlantic... and the track forecast for the next 48 hours has this feature shove this system west into the waters between the Cayman Islands and Central America. After that time the models generally agree on this system becoming quasi-stationary as the next upper trough/surface frontal system that arrives into the north-central US erodes the steering eastern US surface ridge and merges with the western Atlantic upper trough/surface frontal system. In the wake of the re-enforced western Atlantic frontal system a deep-layer ridge develops over the eastern and central US... however the quasi-stationary effect is due to the eastern/central US ridge and western Atlantic trough tugging this system in opposite directions. Through 72 hours I forecast little intensification of the quasi-stationary system due to westerly shear introduced by the north-central US upper trough which proceeds to merge with the western Atlantic upper trough. By day 4 the force of the eastern/central US deep-layer ridge begins to push a southwest lobe of the re-enforced cool-core western Atlantic upper trough into the western Caribbean... with the western Caribbean cool-core upper vortex then pushed further southwest toward Central America by the force of the thunderstorm latent heat release of this system by day 5. During the day 4 period the incoming upper vortex tries to lift this system northeast... however the deep-layer ridge blocks this progress and so I only show a slow northeast drift. Once the upper vortex has a further south position by day 5... I begin to bend the track on an increasingly faster northwest to west turn in the flow between the upper vortex and deep-layer ridge. Regarding the intensity forecast during this time... I finally show strengthening to a stronger tropical storm by day 4 as the incoming upper vortex reduces westerly shear levels. I prefer to not show hurricane strength on day 4 as that timeframe is the end of the prolonged quasi-stationary period which by then could result in upwelled cooler water... and also because the upper vortex will be blocking the western upper outflow of this system. Once this system moves faster on day 5 upwelled cooler waters are no longer a concern and I show hurricane strength... however I show gradual instead of rapid intensification as the position of the upper vortex would be blocking the southern outflow of this system.


The periods of rainfall affecting Jamaica and Hispaniola (Haiti and the Dominican Republic) appear to have ended as the latest satellite imagery shows the thunderstorm bands have become increasingly lopsided toward the south half of this system. Interests in the Cayman Islands and Central America should continue to monitor the progress of this system for possible tropical cyclone impacts (heavy rain... gusty winds... coastal surf) in the days ahead as this system is forecast to track erratically in their vicinity in the days ahead. Interests in Belize... the Yucatan peninsula... and western Cuba should also be aware of this system as long-range model trends are for an ongoing westward or northwestward swing in 5+ days.

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

0 Hr Position (0600Z Nov 13)... Tropical low centered south-southeast of Jamaica at 16.5N-76.5W

IOH 24 Hr Forecast (0600Z Nov 14)... 35 mph maximum sustained wind tropical depression centered southwest of Jamaica at 16.5N-79W

IOH 48 Hr Forecast (0600Z Nov 15)... 45 mph maximum sustained wind tropical storm centered south of the Cayman Islands at 16.5N-81.2W

IOH 72 Hr Forecast (0600Z Nov 16)... 45 mph maximum sustained wind tropical storm centered south of the Cayman Islands at 16.5N-81.2W

IOH 96 Hr Forecast (0600Z Nov 17)... 60 mph maximum sustained wind tropical storm centered south of the Cayman Islands at 17N-81W

IOH 120 Hr Forecast (0600Z Nov 18)... 80 mph maximum sustained wind hurricane centered just southwest of the western Cayman Islands at 17.5N-82.5W

*****National Hurricane Center (hurricanes.gov) official outlook as of 7 AM EDT*************************

Formation chance through 48 hours... 90%

Formation chance through 7 days... 90%


AREA OF INTEREST #50... More recent satellite image of the cold core upper vortex centered over the Iberian peninsula as of 1500Z this morning... this feature is expected to continue retrograding westward in the far eastern Atlantic where it may trigger subtropical development:

Monitoring for possible subtropical development in the far eastern Atlantic and in the vicinity of the Canary Islands in the days ahead. The origin feature is a classical upper trough/surface frontal system that moved into western Europe from the eastern Atlantic on November 7 and 8. By the 8th this system split into a cut-off upper vortex (and associated surface low that was triggered by the divergence zone of the upper vortex) just west of the Canary Islands and another upper vortex over western Europe. In recent days the warm southerly flow ahead of a series of vigorous open central Atlantic surface frontal lows pumped up a northeast Atlantic warm-core deep-layer ridge... with the force of the deep-layer ridge fusing the previous western Europe and Canary Islands upper vortices into a singular upper vortex over the Iberian peninsula of Europe (Portugal/ Spain). As of last evening split flow upper divergence between the northwest side of the upper vortex and south side of the deep-layer ridge was triggering a surface trough of low pressure on the north coast of the Iberian peninsula per NHC TAFB surface analyses. More recently the upper vortex has accelerated west across the Iberian peninsula and into offshore far eastern Atlantic waters while pushed by the deep-layer ridge... with the southeast divergence zone of the upper vortex triggering a surface low on the southwest coast of the Iberian peninsula.


Going forward... the upper vortex and developing surface low/ cyclone become vertically stacked into a deep-layer cyclone positioned in offshore of waters north of the Canary Islands. Although water temps along the 5-day track of this system are 20 to 22 deg C... the temps of the upper vortex are rather cold and potentially de-stabilizing (200 mb heights at the core of the upper vortex well below 1200 dekameters). This thermal profile could therefore allow for a core of thunderstorms and tropical characteristics to develop at the core of the surface layer of the cyclone... and this will mark the 50th tropical Atlantic area of interest tracked on this site this year. By 72 hours a new warm-core deep-layer ridge develops in the north-central Atlantic... within the warm sector of the current and vigorous western Atlantic frontal system. The new deep-layer ridge is likely to push the deep-layer cyclone southwest closer to Madeira island during that timeframe. By 96 hours the force of the deep-layer ridge forces the upper layer of the cyclone to elongate into a SW/ NE tilted upper trough... with the tilted upper trough and surface cyclone drifting northeast toward a passing high-latitude upper trough fragment that moves around the north side of the deep-layer ridge (note this upper trough fragment will be a north fracture of the current western Atlantic upper trough). Then by 120 hours the southeast side of the deep-layer ridge takes over the steering by pushing the elongated upper trough south and surface cyclone on a south to south-southwest dive into the Canary Islands. The models indicate the south dive of the surface cyclone may lag the dive of the upper trough... placing it beneath the back suppressive convergence zone of the upper trough which would help weaken the surface cyclone. Therefore by 120 hours I trim the odds of subtropical cyclone formation down from the peak. I assign a low 20% peak odds of subtropical development while waiting to see if the models remain consistent through the next update cycle... and will assign higher odds in future updates should the models remain consistent on showing the current solution and/ or future satellite observations warrant. Regardless of subtropical development or not... odds of gusty winds and coastal surf increase for the Canary Islands by this weekend.

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

IOH 24 Hr Outlook (0600Z Nov 14)... 0% chance of subtropical cyclone formation (south coast of Portugal near 36.8N-8.8W)

IOH 48 Hr Outlook (0600Z Nov 15)... 10% chance of subtropical cyclone formation (northeast of the Canary Islands near 36.8N-14W)

IOH 72 Hr Outlook (0600Z Nov 16)... 20% chance of subtropical cyclone formation (just north-northwest of Madeira near 35.5N-18W)

IOH 96 Hr Outlook (0600Z Nov 17)... 20% chance of subtropical cyclone formation (northeast of Madeira near 36N-16W)

IOH 120 Hr Outlook (0600Z Nov 18)... 10% chance of subtropical cyclone formation (Madeira near 32.8N-17W)

*****National Hurricane Center (hurricanes.gov) official outlook as of 7 AM EDT*************************

Not in the official outlook


...COMPUTER MODEL SUMMARY...

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


1200Z (Nov 11) CMC Model Run...

**For area of interest #49... tropical low reaches waters just SW of Jamaica at 60 hours then moves west toward Belize/Mexico border through 168 hours


1200Z (Nov 12) CMC Model Run...

**For area of interest #49... tropical cyclone formation suggested just offshore of eastern Honduras by 72 hours... wobbles south into the eastern Honduras coast through 102 hours... proceeds west-northwest then northwest across the western Caribbean waters and makes landfall on the east-central Yucatan peninsula coast by 150 hours... continues north-northwest into the south-central Gulf of Mexico through 168 hours

**For area of interest #50... deep-layer cyclone materializes north of the Canary Islands through 72 hours... initially wobbles northeast then finally southward into Madeira through 132 hours while weakening.... dissipates just south of Madeira by 156 hours


1200Z (Nov 11) ECMWF Model Run...

**For area of interest #49... tropical low reaches waters just south of Jamaica at 48 hours... tropical cyclone formation suggested just offshore of eastern Honduras at 96 hours... while strengthening reverses course while moving back east into the waters south of Jamaica by 144 hours... centered SSE of Jamaica by 168 hours as a potentially intense hurricane


1200Z (Nov 12) ECMWF Model Run...

**For area of interest #49... tropical cyclone formation suggested offshore of eastern Honduras at 60 hours... drifts west then southeast through 102 hours into a position just offshore of the eastern tip of Honduras through 102 hours while gaining hurricane strength... while maintaining hurricane strength moves on a west-northwest track that parallels the north-facing Honduras shore and makes landfall in Belize at 156 hours... inland weakening hurricane then curves north-northwest into the southeastern Yucatan peninsula through 168 hours

**For area of interest #50... deep-layer cyclone materializes north of the Canary Islands through 78 hours... initially wobbles northeast then finally southward into Madeira through 138 hours while weakening.... dissipates southeast of Madeira by 156 hours


1800Z (Nov 11) GFS Model Run...

**For area of interest #49... tropical low reaches waters just south of Jamaica at 36 hours... tropical cyclone formation suggested just offshore of eastern Honduras at 78 hours... while strengthening drifts southwest into the eastern Honduras coast through 84 hours... drifts south into the Nicaragua/Honduras border through 105 hours while weakening due to land interaction... weakens to a remnant low while quasi-stationary over the Nicaragua/Honduras border through 138 hours... remnant low proceeds west-northwest along north-facing Honduras coast through 168 hours.


1200Z (Nov 12) GFS Model Run...

**For area of interest #49... tropical cyclone formation suggested south of the Cayman Islands at 45 hours... rapidly intensifies into a strong hurricane while stalling at a position east-northeast of eastern Honduras through 81 hours... while becoming a large and intense hurricane remains quasi-stationary through 135 hours... the intense hurricane then moves northwest across the western Caribbean with the center reaching the Yucatan channel (between northeast corner of Yucatan peninsula and west tip of Cuba) through 168 hours.

**For area of interest #50... deep-layer cyclone materializes north of the Canary Islands through 78 hours... initially wobbles northeast then finally southward into Madeira through 138 hours while weakening.... while continuing south dissipates over the southern Canary Islands at 168 hours


1800Z (Nov 11) NAVGEM Model Run...

**For area of interest #49... tropical low reaches waters just south of the Cayman Islands at 60 hours... tropical cyclone formation suggested offshore of eastern Honduras by 90 hours... while moving west then southeast strengthens and then makes landfall over the eastern Honduras coast by 132 hours... while continuing to strengthen the tropical cyclone reverses course and moves northwest across the western Caribbean and into the waters just offshore of the southeastern Yucatan peninsula coast through 168 hours.


1200Z (Nov 12) NAVGEM Model Run...

**For area of interest #49... tropical cyclone formation suggested south of the Cayman Islands at 42 hours... while drifting west then back east to the same initial position south of the Cayman Islands the tropical cyclone becomes a large and intense hurricane through 120 hours... center of the intense hurricane then turns north-northwest and passes just west of the Cayman Islands at 150 hours then makes landfall over western Cuba at 162 hours... the center then begins to turn northeast toward the Florida Keys by 168 hours

**For area of interest #50... deep-layer cyclone materializes north of the Canary Islands through 54 hours... makes one complete counter-clockwise loop just north of Madeira through 96 hours then is quasi-stationary at this location through 150 hours... afterwards drifts southwest to a position just west of Madeira through 168 hours

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