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 #85

Updated: Aug 27

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


...FRIDAY AUGUST 26 2022 3:52 AM EDT...

The Atlantic tropics remain calm as the following two areas of interest are not showing signs of developing in the short-term:

(1) A pair of vigorous tropical waves of low pressure in the eastern tropical Atlantic have the potential to merge into an organizing tropical low pressure... see area of interest #20 section below for more information.

(2) See area of interest #22 section below for an update on the tropical low pressure area which has recently crossed the Lesser Antilles and is now in the eastern Caribbean Sea.


Elsewhere...a sprawling tropical wave of low pressure currently over central Africa is expected to enter the eastern tropical Atlantic in approximately four days. At present there is a strong agreement among multiple global computer models that this wave could develop after moving offshore. However the more recent model runs have trended with a more gradually developing wave that initially struggles to consolidate due to multiple low pressure centers... bringing the potential for tropical cyclone formation beyond the 5-day forecast period. As a result I have not added this tropical wave as an area of interest in this update. Once the potential for tropical cyclone formation is within the 5-day forecast range... and if model solutions and/or current observations warrant... will add the wave as an area of interest as needed in future updates.


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 are designated #20 and #22 as I designated the other nineteen of this year... as well as #21... in previous birdseye view posts on the home page. 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.


AREA OF INTEREST #20...A pair of closely spaced and vigorous tropical waves of low pressure continue sliding west across the eastern tropical Atlantic. As of 0000Z earlier this evening the eastern of the two waves was producing a rotating circular thunderstorm mass just southwest of the Republic of Cabo Verde Islands...or in the vicinity of 13N-25W. The western of the two appeared to be located near 10N-31W with its associated thunderstorm mass lopsided to its west side... as its east side appears to be open to the eastern wave. This suggests the eastern wave and its rotating thunderstorm mass is becoming the dominant feature in the region as the two waves are trying to merge. Should the merger be successful... we could end up with a broad tropical low pressure area underneath the ongoing favorable tropical upper ridge in the region featuring low shear and upper outflow. The only thing barring development in the region is a mass of dry saharan air lurking just to the north... some of which has become ingested into the circulation of the eastern tropical wave. In this update I have not raised odds of tropical cyclone formation above 40% as their are some questions regarding how much dry saharan air could become ingested into this area of interest... and it is possible that the two waves spend more time competing with each other for low-level inflow and upper outflow instead of merging into a singular consolidating disturbance.

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

IOH 24 Hr Outlook (0000Z Aug 27)...0% chance of tropical cyclone formation (eastern tropical Atlantic near 13N-29W)

IOH 48 Hr Outlook (0000Z Aug 28)...15% chance of tropical cyclone formation (eastern tropical Atlantic near 13N-34W)

IOH 72 Hr Outlook (0000Z Aug 29)...30% chance of tropical cyclone formation (eastern tropical Atlantic near 13N-39W)

IOH 96 Hr Outlook (0000Z Aug 30)...40% chance of tropical cyclone formation (central tropical Atlantic near 13N-44W)

IOH 120 Hr Outlook (0000Z Aug 31)...40% chance of tropical cyclone formation (central tropical Atlantic near 13N-49W)


AREA OF INTEREST #22...The tropical wave of low pressure that was crossing the Lesser Antilles 24 hours ago is now well into the Caribbean Sea at 70W longitude... and over the last couple of days its southeast side has been leaving behind a surface trough of low pressure. Satellite animation over the last several hours suggests the maximum rotation of the surface trough crossed the central Lesser Antilles islands... and is now located in the far eastern Caribbean Sea just west of the central islands. The CIMSS 850 mb vorticity product also agrees with this positioning of the maximum rotation(http://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). Over the next few days the surface trough is expected to continue west-northwest across the Caribbean Sea while steered around the southwest side of the Atlantic surface ridge. The forecast track in the updated outlook below is adjusted based on the fact that the observed maximum rotation of the trough is north and west of the previous forecast. Short-term odds of tropical cyclone formation remain 0% as the surface trough continues to struggle in terms of having sustained thunderstorm activity. A subsequent peak of 10% odds is shown at 48 and 72 hours as the surface trough may take advantage of the current upper ridge in the Caribbean providing a low shear environment... with the upper ridge also potentially allowing this system to establish a favorable upper outflow pattern. For 96 and 120 hours... odds of development are dropped back to 0% as the latest model runs show the inverted upper trough currently near Bermuda retrograding southwest over this disturbance and suppressing upper outflow. The GFS has returned to showing this disturbance developing... this time in the western Caribbean Sea and just beyond 5 days...with also the NAVGEM as of 1800Z on Thursday beginning to agree. This is why the outlook below continues through 5 days despite ending with 0% odds... in preparation for possible western Caribbean development just beyond the 5-day period. In the modeling... the mechanism for potential western Caribbean development is upper divergence between the west side of the inverted upper trough and southeast side of the current Gulf of Mexico upper ridge. The forecast track from 96 to 120 hours takes a southwestward drifting excursion in anticipation of this disturbance potentially re-organzing at the location of the aformentioned upper divergence maximum.


This disturbance has potential to produce two rounds of thunderstorm activity and associated heavy rainfall... the first this weekend over the southwestern Dominican Republic... Haiti... and Jamaica. The activity could then take a pause by early next week... followed by the development of the second round of activity in the western Caribbean Sea by the middle of next week.

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

IOH 24 Hr Outlook (0000Z Aug 27)...0% chance of tropical cyclone formation (eastern Caribbean Sea near 15.5N-66W)

IOH 48 Hr Outlook (0000Z Aug 28)...10% chance of tropical cyclone formation (just offshore of the southwestern Dominican Republic near 16.5N-71W)

IOH 72 Hr Outlook (0000Z Aug 29)...10% chance of tropical cyclone formation (just southwest of Haiti and just southeast of Jamaica near 17.5N-75W)

IOH 96 Hr Outlook (0000Z Aug 30)...0% chance of tropical cyclone formation (between Jamaica and the Cayman Islands near 18.5N-79W)

IOH 120 Hr Outlook (0000Z Aug 31)...0% chance of tropical cyclone formation (south of the Cayman Islands near 18N-80.2W)


...COMPUTER MODEL SUMMARY...

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


1200Z (Aug 25) CMC Model Run...

**For area of interest #20...no development shown

**For area of interest #22...no development shown

**Vigorous tropical wave emerges from the west coast of Africa at 108 hours... organizes into a southwest-northeast elongated low pressure circulation over the Republic of Cabo Verde Islands at 138 hours... at 144 hours northeast end of circulation develops a distinct low pressure center that swings west and passes just north of the Republic of Cabo Verde Islands through 168 hours.


1200Z (Aug 25) ECMWF Model Run...

**For area of interest #20...pair of tropical waves in eastern tropical Atlantic gradually merge into a tropical low over the next 48 hours... tropical low becomes tropical cyclone by 168 hours located at 15.5N-52.5W

**For area of interest #22...no development shown

**Vigorous tropical wave featuring broad low pressure center emerges from the west coast of Africa at 120 hours... broad low pressure consolidates into a tropical cyclone over the northwestern Republic of Cabo Verde Islands at 144 hours... tropical cyclone located at 15.5N-31W at 168 hours


1800Z (Aug 25) GFS Model Run...

**For area of interest #20...no development shown

**For area of interest #22...tropical low pressure becomes increasingly broad but better defined by the time it reaches the western Caribbean Sea at 138 hours... broad tropical low gradually strenghthens and centered at 19.8N-85W at 168 hours.

**Vigorous tropical wave emerges from west coast of Africa at 96 hours... develops a pair of low pressure centers (one just southeast of the Republic of Cabo Verde Islands and a second just offshore of the Mauritania/Senegal border) at 117 hours... eastern of the two centers becomes the dominant and passes just north of the Republic of Cabo Verde Islands through 168 hours while the western of the two centers becomes stationary due to fujiwhara interaction with the dominant center and eventually it dissipates.


1800Z (Aug 25) NAVGEM Model Run...

**For area of interest #20...no development shown

**For area of interest #22... tropical low pressure becomes increasingly broad but better defined by the time it reaches the western Caribbean Sea at 150 hours... center of broad tropical low located at 19.5N-85W at 168 hours

**Vigorous tropical wave emerges from west coast of Africa at 72 hours... becomes a tropical low midway between the west coast of Africa and Republic of Cabo Verde Islands at 84 hours... although tropical low gradually strengthens while moving into the Republic of Cabo Verde Islands through 168 hours it also becomes rather elongated southwest-to-northeast.

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