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 #154

*******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 OCTOBER 19 2020 9:55 PM EDT...

See Tropical Storm Epsilon section below for the only active tropical cyclone in the Atlantic basin. See area of interest section below for western Caribbean Sea activity being monitored for development.  TROPICAL STORM EPSILON...The central Atlantic surface low pressure spawned by the western Atlantic upper vortex had produced increasing thunderstorms in the east half of the circulation through this morning...producing latent heat release warming to establish warm core anticyclonic outflow to the east of the upper vortex and south of upper vorticity approaching from the northeast Atlantic upper vortex. The thunderstorm activity became better organized to upgrade the surface low to tropical depression twenty-seven...and then Tropical Storm Epsilon as the outflow has allowed for strengthening. The tropical storm has become stationary while its southward drift has ended...as Epsilon is now reversing to a northwest turn around the upper vorticity approaching from northeast which is quickly diving towards the western Atlantic upper vortex to the west. As long as Espilon stays east of the western Atlantic upper vortex...it will be able to continue to produce expansive warm core outflow in between that vortex and the northeast Atlantic upper vortex...and significant strengthening is on the table. In fact I forecast Epsilon to become a category 2 hurricane before reaching 26 deg C and cooler water by 96+ hours...higher than the 5 PM EDT NHC forecast. My short term forecast track is adjusted northward due to the current position of Epsilon...which shows Epsilon going northwest around the east side of the upper vortex. A west angle is kept through 96 hours as a surface ridge will be building to the north under the convergence zone of one of the upper troughs to eject from the central North America upper vortex once that vortex finally breaks up...with a straight north angle shown by 120 hours from a surface ridge weakness to then pass north of Epsilon under the eastern divergence zone of the next upper trough tied to the collapsing North America upper vortex. My long term track forecast is shifted eastward as Epsilon has already established warm anticyclonic outflow all the way up to the 200 mb layer of the atmosphere...making it more difficult for Epsilon and its outflow to whirl under the western Atlantic upper vortex if it were a shallower warm core system or subtropical system. This could mean less rain and wind impact to Bermuda from Epsilon later this week...but coastal sea swells are definitely on the table. Interest here should watch Epsilon carefully as there is the usual forecast track uncertainty in the longer range. ******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official  forecast*********** 0 Hr Position (1800Z Oct 19)...45 mph maximum sustained wind tropical storm centered at 25.5N-55.5W IOH 24 Hr Forecast (1800Z Oct 20)...60 mph maximum sustained wind tropical storm centered at 25.5N-55.5W IOH 48 Hr Forecast (1800Z Oct 21)...90 mph maximum sustained wind hurricane centered at 26.5N-57W IOH 72 Hr Forecast (1800Z Oct 22)...105 mph maximum sustained wind hurricane centered at 30.5N-60W IOH 96 Hr Forecast (1800Z Oct 23)...105 mph maximum sustained wind hurricane centered just east-northeast of Bermuda at 33N-62.5W IOH 120 Hr Forecast (1800Z Oct 24)...80 mph maximum sustained wind hurricane centered in the northwest Atlantic at 37.5N-62.5W

AREA OF INTEREST #1....The tail end of one of the surface fronts tied to the central Atlantic upper vortex and a tropical wave passing through the region have combined with the outflow of the upper ridge axis in the region to produce a broad area of low surface pressure. This system is poorly organized while producing scattered showers and thunderstorms that span from Cuba to the southern Caribbean...and while lacking a tightly defined center. The 1200Z model consensus is for the surface low pressure to consolidate toward the north due to the divergence zones of shortwave upper troughs to eject from Texas...but this places the system in westerly shear on the north side of the upper ridge axis such that no development is shown. However I forecast the disturbance to consolidate further south along 17N latitude where the outflow of the upper ridge axis is centered in the longer range on the 1200Z GFS. However I have 0% odds of development in the short term to give time for this sprawling system to consolidate...and I keep odds of development at a low 10% in the long term as there is no guarantee that this system will consolidate enough to become a tropical cyclone. My policy with this system has been to keep peak odds of development at a low 10% until there were definitive signs of a consolidated low pressure system developing...and it is interesting to note the NHC outlook which had higher odds in previous days has now lowered odds of development to 10%.


On a final note...the models agree that if and when a consolidated surface low pressure forms that the track will drift westward under the influence of persistent surface ridging to the north. Therefore statements for the Yucatan peninsula region...including Belize...in regards to this system have been added to the home page bulletins of this site. ******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook*********** IOH 24 Hr Outlook (1800Z Oct 20)...0% chance of tropical cyclone formation (western Caribbean Sea near 15N-80W) IOH 48 Hr Outlook (1800Z Oct 21)...0% chance of tropical cyclone formation (western Caribbean Sea near 16.5N-82.5W) IOH 72 Hr Outlook (1800Z Oct 22)...10% chance of tropical cyclone formation (western Caribbean Sea near 17N-85W) IOH 96 Hr Outlook (1800Z Oct 23)...10% chance of tropical cyclone formation (east coast of the Yucatan peninsula just south of the Belize/Mexico border near 17N-87.5W) IOH 120 Hr Outlook (1800Z Oct 24)...0% chance of tropical cyclone formation (Belize/Mexico/Guatemala border near 17N-89W)

...COMPUTER MODEL SUMMARY... Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/) 1200Z CMC Model Run...For Tropical Storm Epsilon...gradually strengthens and passes just east of Bermuda at 84 hours...reaches 35N-62.5W at 120 hours. For area of interest #1...broad low pressure forms near 20.5N-85W at 18 hours...gradually moves west-northwest across southern Gulf of Mexico without tropical cyclone formation. 1200Z ECMWF Model Run...For Tropical Storm Epsilon...gradually strengthens and passes just east of Bermuda at 96 hours...reaches 33.5N-63.5W at 120 hours. For area of interest #1...broad low pressure forms near 20N-86W at 24 hours...gradually moves west-northwest across southern Gulf of Mexico without tropical cyclone formation. 1200Z GFS Model Run...For Tropical Storm Epsilon...rapidly strengthens in short term and passes just east of Bermuda at 96 hours...reaches 33N-63W at 120 hours. For area of interest #1...broad low pressure forms over the northeastern Yucatan peninsula at 30 hours...gradually moves west-northwest across southern Gulf of Mexico without tropical cyclone formation. 1200Z NAVGEM Model Run... For Tropical Storm Epsilon...gradually strengthens while passing well east of Bermuda at 72 hours...turns east and reaches 35.5N-56W at 120 hours. For area of interest #1...broad low pressure forms at 20.5N-85W at 18 hours...gradually moves west-northwest across southern Gulf of Mexico without tropical cyclone formation.

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