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 2022 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #97

Updated: Sep 12

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


...SATURDAY SEPTEMBER 10 2022 8:45 AM EDT...


See Hurricane Earl and area of interest #27 to #29 sections below for updates on the current tropical systems being closely monitored in the Atlantic basin. Elsewhere... the upper vortex currently in the western Gulf of Mexico is producing thunderstorm activity in the eastern Gulf with its eastern divergence zone. However there are no signs of a subtropical or tropical disturbance developing in this area.


New to this site this year... I will be sequentially numbering up areas of interest for possible Atlantic tropical development. In this scheme... will reset back to #1 at the start of next year (January 2023). The current areas of interest in this blog post is designated #27 and #29 as the other twenty-six were mentioned in previous birdseye view posts. This scheme is to reduce confusion as Atlantic tropical activity increases during the peak of the hurricane season... when multiple simultaneous areas of interest begin and end which previously required shuffling around the area of interest numbers from update to update.


HURRICANE EARL... The hurricane that was passing just east of Bermuda on Thursday has spent much of Friday and this early morning hauling northeastward away from Bermuda and into the northwestern Atlantic waters offshore of southeastern Newfoundland. This is due to Earl's interaction with the upper trough that has recently departed eastern Canada. Specifically the surface northerly flow in Earl's northwest quadrant has pulled cool air associated with the trough southward... helping the trough to amplify. In turn a strengthening southerly jet on the east side of the amplifying upper trough has induced the rapid northeast acceleration in the hurricane's forward speed. Increasing divergence on the east side of the amplifying upper trough has also been aiding Hurricane Earl which allowed it to re-intensify into a category 2 with 105 mph maximum sustained winds over the last day. More recently Earl looks like a hurricane beginning a gradual transition into a non-tropical frontal cyclone while still having a thunderstorm core with an eye... but with the cooler dry air associated with the upper trough encroaching and eroding away the outer thunderstorm activity just west of the core. Also helping the transition is Earl has just crossed the 26 deg C sea surface temperature isotherm and is now moving into cooler waters. The above-discussed interaction between Earl and the upper trough will cause the trough to amplify into an upper vortex... with Earl whirling beneath the center of the vortex to a location just offshore of southeastern Newfoundland. The remnant frontal cyclone of Earl is expected to meander at this location between 24 and 48 hours... after which time the upper vortex shifts east as a typical mid-latitude feature. As it does so... the remnant frontal cyclone of Earl will also shift east in the long-range and gradually weaken while trapped below the core of the upper vortex where there is a lack of upper divergence.


Coastal sea swells will continue to increase to strong levels for Newfoundland today... with gale force winds generated by Earl and its eventual remnant frontal cyclone overspreading southeastern Newfoundland by late today. Gale force winds over southeastern Newfoundland could last through Monday as the remnant frontal cyclone meanders in the 24 to 48 hour period as mentioned above. I recommend that interests in southeastern Newfoundland should be finishing preparations for gale force conditions by the early afternoon.

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

0 Hr Position (0600Z Sep 10)... 105 mph maximum sustained wind hurricane centered in the northwestern Atlantic at 41.2N-53.5W

IOH 24 Hr Forecast (0600Z Sep 11)... Hurricane-force non-tropical remnant frontal cyclone centered just southeast of Newfoundland at 45N-52W


AREA OF INTEREST #27...The tropical low pressure that has been moving west-northwest across the central Atlantic is beginning to separate from the north end of its parent tropical wave while turning increasingly north into the surface ridge weakness being generated by Hurricane Earl and the eastern divergence zone of the amplifying upper trough that Earl is interacting with. The nearby upper vortex to the west continues to shear the thunderstorm activity well north of the tropical low pressure's center of rotation. The thunderstorm activity has grown into a sizeable mass supported by split flow upper divergence between the north side of the upper vortex and the northwest side of a cell of tropical upper ridging to the east... however tropical cyclone formation is no longer expected as the tropical low moves increasingly into the shearing winds on the east side of the upper vortex. The shear will also be continued by the south side of the amplifying upper trough interacting with Earl... once the south side of the upper trough absorbs the upper vortex. This is my final statement on this area of interest on this blog as tropical cyclone formation is no longer expected.

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

IOH 24 Hr Outlook (0600Z Sep 11)...0% chance of tropical cyclone formation (central Atlantic near 27.5N-51W)


AREA OF INTEREST #28...The center of rotation associated with the tropical wave of low pressure currently in the eastern tropical Atlantic is located near 9N-29.5W as of this writing. The rotation continues to lack thunderstorm activity with still only one broken band currently present west of the center. This disturbance is expected to continue steadily westward across the tropical Atlantic and around the south side of the current eastern Atlantic surface ridge. The forecast track points are nudged southward to account for the current position of the center of rotation. In the longer range as Earl and its eventual remnant cyclone eventually weaken... the associated surface ridge weakness closes by 3+ days which should allow this system to continue westward.


Regarding development potential...this disturbance will be in an environment of low shear and upper outflow beneath the tropical upper ridge in the region. However given the struggle that this circulation has had in generating thunderstorms over the last couple of days... this suggests this system is ingesting dry Saharan air lurking to the north. And combined with the lack of support in the latest computer model runs... the NHC has removed this system from thier tropical weather outlook. In this update I have chosen to maintain this system as an area of interest given the persistence of its rotation and perhaps its southern location allowing it to eventually ward off the effects of the dry Saharan air. However I have notably lowered my peak odds of tropical cyclone formation to 10%.

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

IOH 24 Hr Outlook (0600Z Sep 11)...0% chance of tropical cyclone formation (eastern tropical Atlantic near 9.5N-34.5W)

IOH 48 Hr Outlook (0600Z Sep 12)...0% chance of tropical cyclone formation (eastern tropical Atlantic near 10N-39.5W)

IOH 72 Hr Outlook (0600Z Sep 13)...10% chance of tropical cyclone formation (central tropical Atlantic near 10.5N-44.5W)

IOH 96 Hr Outlook (0600Z Sep 14)...10% chance of tropical cyclone formation (central tropical Atlantic near 11.5N-49.5W)

IOH 120 Hr Outlook (0600Z Sep 15)...10% chance of tropical cyclone formation (central tropical Atlantic near 12N-54.9W)


AREA OF INTEREST #29... Satellite image highlighting a pair of tropical waves of low pressure spanning the central and western regions of Africa... with each wave marked by a red-dashed line. Image taken at 0600Z:

Satellite imagery suggests a pair of tropical waves of low pressure over the interior regions of western and central Africa... with one wave axis near 4E longitude and a second wave which has become better defined to the west near 5W longitude. The more recent model runs have suggested a disturbance moving offshore of Africa in a sooner timeframe... perhaps while now picking up on the better defined western wave and my updated forecast track below is adjusted westward accordingly. Models are also representing this disturbance as an initially broad low pressure area... perhaps a suggestion that the two tropical waves will become entangled with the end result being a broad system. While atmospheric conditions are expected to be favorable for development as a disturbance becomes established offshore of Africa... due to the ongoing presence of a tropical upper ridge in the region with low shear and upper outflow... the thermodynamic conditions offshore of Africa this hurricane season have been hostile over the last several days with air that has been too dry. Also the latest suite of model runs have backed off in showing development... and to add to that the potential for a broad instead of a consolidated disturbance does not help make the case for development. Therefore my peak odds of tropical cyclone formation remain at a low 10% for this area of interest (this is below the NHC 5-day tropical weather outlook's 30% as of this writing).

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

IOH 24 Hr Outlook (0600Z Sep 11)...0% chance of tropical cyclone formation (western Africa near 10.5N-7W)

IOH 48 Hr Outlook (0600Z Sep 12)...0% chance of tropical cyclone formation (western Africa near the eastern tropical Atlantic coast near 11N-13W)

IOH 72 Hr Outlook (0600Z Sep 13)...0% chance of tropical cyclone formation (offshore of western Africa near 11.5N-19W)

IOH 96 Hr Outlook (0600Z Sep 14)...10% chance of tropical cyclone formation (south-southwest of the Republic of Cabo Verde Islands near 12N-25W)

IOH 120 Hr Outlook (0600Z Sep 15)...10% chance of tropical cyclone formation (eastern tropical Atlantic near 12.5N-31W)


...COMPUTER MODEL SUMMARY...

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


0000Z (Sep 10) CMC Model Run...

**For Hurricane Earl... Whirls beneath the center of upper trough/vortex while transitioning into a frontal cyclone with the frontal cyclone stalling near 44N-52.5W (southeast of Newfoundland) from 24 to 48 hours... remnant frontal cyclone turns east and reaches 43N-39.5W at 120 hours.

**For area of interest #27... tropical low dissipates near 27.5N-50.5W at 24 hours

**For area of interest #28... no development shown

**For area of interest #29... tropical wave emerges from west coast of Africa at 54 hours... organizes into a broad tropical low southeast of the Republic of Cabo Verde Islands at 78 hours... tropical low gradually consolidates while moving west-northwest and reaches 20N-40.5W at 168 hours


0000Z (Sep 10) ECMWF Model Run...

**For Hurricane Earl... Whirls beneath the center of upper trough/vortex while transitioning into a frontal cyclone with the frontal cyclone stalling near 44N-52.5W (southeast of Newfoundland) from 24 to 48 hours...remnant frontal cyclone turns east and reaches 43.5N-41W at 120 hours.

**For area of interest #27... tropical low dissipates in the next 24 hours

**For area of interest #28... no development shown

**For area of interest #29... tropical wave emerges from west coast of Africa at 48 hours... organizes into a tropical low midway between west coast of Africa and Republic of Cabo Verde Islands by 72 hours while located near 14.8N-20W... tropical low passes over the southern Republic of Cabo Verde Islands at 96 hours... tropical low continues west-northwest and reaches 20N-40W at 168 hours


0000Z (Sep 10) GFS Model Run...

**For Hurricane Earl... Whirls beneath the center of upper trough/vortex while transitioning into a frontal cyclone with the frontal cyclone stalling near 44N-53.8W (south-southeast of Newfoundland) from 24 to 48 hours...remnant frontal cyclone turns east and reaches 43.5N-39.5W at 120 hours.

**For area of interest #27... tropical low dissipates near 25.5N-50.5W at 21 hours

**For area of interest #28... no development shown

**For area of interest #29... tropical wave emerges from west coast of Africa at 63 hours... coalesces into a broad tropical low near 12.5N-20.5W at 75 hours... tropical low weakens back to a wave while crossing 35W longitude by 126 hours

**Upper trough currently crossing central Canada deposits cut-off upper vortex over northern Illinois at 54 hours where it produces a frontal low in the region... cut-off upper vortex elongates into an upper trough sliding across the eastern US and Atlantic Canada through 120 hours with the associated frontal low moving across Atlantic Canada and the tail end of its cold front midway between Bermuda and the US east coast... south end of upper trough cuts-off into a vortex over Georgia at 144 hours whose eastern divergence zone triggers a surface low along tail end of cold front near 31.2N-78.5W... as upper vortex moves into western Carolinas the supported surface frontal low transitions into a subtropical cyclone moving north-northeast into the North Carolina Outer Banks through 168 hours.


0000Z (Sep 10) NAVGEM Model Run...

**For Hurricane Earl... Whirls beneath the center of upper trough/vortex while transitioning into a frontal cyclone with the frontal cyclone stalling near 44.5N-51W (southeast of Newfoundland) from 24 to 48 hours...remnant frontal cyclone turns east and reaches 44N-37W at 120 hours.

**For area of interest #27... tropical low dissipates near 25.5N-51.2W at 18 hours

**For area of interest #28... tropical low continues west and reaches waters east of the Lesser Antilles near 16N-59W at 168 hours

**For area of interest #29... tropical wave emerges from west coast of Africa at 54 hours... coalesces into a broad tropical low which passes over the Republic of Cabo Verde Islands at 144 hours... tropical low gradually consolidates while reaching 18N-34W at 168 hours

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