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 #100

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


...WEDNESDAY SEPTEMBER 14 2022 1:20 AM EDT...

The short-term focus for potential tropical development in the Atlantic remains with a trio of tropical waves of low pressure lined up from the central Atlantic to western Africa... see area of interest #28 to #30 sections below for an update on each wave. Further west... a broad tropical disturbance could materialize over the western Caribbean... Bay of Campeche... southeastern Mexico... western Central America... and far eastern Pacific in the next five days as follows:

(1) A surface trough of low pressure has materialized in the central Gulf of Mexico over the last few days while produced by the eastern divergence zone of cut-off upper vorticity. Recently this upper vorticity has become absorbed by the upper trough currently over the eastern US... with the surface trough becoming pushed into the southwestern Gulf of Mexico by a surface ridge being built by the western convergence zone of the eastern US upper trough. The southwestern Gulf of Mexico surface trough and outflow of a current upper ridge over southeastern Mexico/western Central America are already producing a broad area of scattered thunderstorms.

(2) Upper vorticity in the Caribbean is expected to gradually fade while remaining cut-off from high-latitude cold air... with whatever remains of that upper vorticity to get swept up into the eastern US upper trough once that trough moves eastward and away. This will allow for the upper ridge in the region to expand in the wake of the upper trough and fading Caribbean upper vorticity. At the surface... the tail end of the cold front to be left behind in the Gulf of Mexico by the eastern US upper trough... the current southwestern Gulf of Mexico surface trough... and the current tropical wave approaching from the central Caribbean Sea may merge into a broad tropical low pressure area supported by the expanding upper ridge's outflow. The broad tropical low pressure area would span the western Caribbean... Bay of Campeche... southeastern Mexico... western Central America... and far eastern Pacific.

(3) Computer model runs favor tropical cyclone formation in the eastern Pacific in regards to the broad tropical low pressure area. However should observations in future updates or future model runs support any development in the Bay of Campeche or western Caribbean... will declare a new area of interest as needed.


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 #28 to #30 as the other twenty-seven 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.


AREA OF INTEREST #28...The axis of the tropical wave of low pressure currently crossing the central tropical Atlantic has been re-analyzed by the NHC TAFB to be aligned with its ongoing low pressure circulation further east. While the circulation has remained defined over the last 24 hours... the associated thunderstorm activity reduced for much of Tuesday perhaps while ingesting dry Saharan air lurking to the north. However thunderstorm activity was not totally absent while grouping into a northwest-southeast band straddling the circulation. More recently the western part of this band has fizzled while a concentrated and growing thunderstorm cluster has developed to the east. Although this cluster initially seems to be where this system might be becoming better organized... in reality the cluster is also east of the circulation center rather than over it. As of 0000Z earlier this evening the circulation center appeared to be passing near 15.5N-46.5W. This system is expected to continue steadily westward across the tropical Atlantic and around the south side of the current Atlantic surface ridge. The updated forecast track below is nudged slighlty north based on the slighlty more north 0000Z center fix relative to the previous forecast. In 48 to 120 hours... a vigorous frontal system is expected over eastern Canada and the northwest Atlantic. The tail end of this frontal system is expected to deposit a cut-off upper trough over the southeastern United States whose eastern divergence zone is expected to support an offshore cold front. The northward component of this area of interests's westward track could increase slighlty on days 4 and 5 while moving toward the cold front forecast to be offshore of the southeastern United States.


Even though this tropical wave of interest continues to maintain a low pressure circulation... I still cap odds of tropical cyclone formation to 20% over the next 72 hours due to uncertainty in the longer range upper wind forecast. The uncertain upper wind pattern lies with the development of the vigorous frontal system over eastern Canada and the northwest Atlantic at 48+ hours. The warm sector of the frontal system is expected to build an upper ridge over the western Atlantic that cuts-off some of the upper vorticity tied to Earl's remnant system and sends it southwestward toward this tropical wave. In the unfavorable scenario... the upper vorticity catches up to the wave where it would increase wind shear and suppress upper outflow. In the favorable scenario... the upper vorticity does not quiet catch up to the wave... leaving the wave in a favorable split flow upper divergence pattern between the west side of the upper vorticity and southeast side of the built-up western Atlantic upper ridge (noting the NAVGEM wants to strengthen this tropical wave into a strong tropical cyclone while picking up on this potentially favorable upper wind scenario). At 96 hours it appears more likely that this system will pass under the core of the western Atlantic upper ridge featuring low shear and upper outflow... and for that timeframe I have raised odds of development to 30%. At 120 hours the cut-off upper trough to be left over the southeastern United States... mentioned in the previous paragraph... could approach this system in a de-amplified state which would increase wind shear in the region... and this is when I taper odds of development back down to 20%.


Note that interests in the northern Lesser Antilles... Virgin Islands... and Puerto Rico may see gusty winds and heavy rains from this tropical wave late this week and into the weekend.

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

IOH 24 Hr Outlook (0000Z Sep 15)...20% chance of tropical cyclone formation (central tropical Atlantic near 16.5N-51.5W)

IOH 48 Hr Outlook (0000Z Sep 16)...20% chance of tropical cyclone formation (east of the northern Lesser Antilles near 17.5N-57W)

IOH 72 Hr Outlook (0000Z Sep 17)...20% chance of tropical cyclone formation (just north of the northern Lesser Antilles near 18.5N-62W)

IOH 96 Hr Outlook (0000Z Sep 18)...30% chance of tropical cyclone formation (north of Puerto Rico near 20.5N-66W)

IOH 120 Hr Outlook (0000Z Sep 19)...20% chance of tropical cyclone formation (just east of the eastern Bahamas near 21.5N-70W)


AREA OF INTEREST #29...The eastern Atlantic tropical wave of low pressure moving through the Republic of Cabo Verde Islands in the last 24 hours has succumbed to dry Saharan air. Specifically the quickly organizing circulation with concentrated thunderstorms that was moving into the islands early Tuesday ingested the surrounding dry air and quickly collapsed into disorganized shower activity over the islands by Tuesday afternoon. The tropical wave is now producing a circulation southwest of the islands... spotted in the vicinity of 13.8N-26W as of 0000Z... featuring some disorganized shower and thunderstorm activity over and south of the circulation center. A general westward track around the south side of the Atlantic surface ridge anticipated over the next few days... with the updated track shifted south and west based on the current center of circulation's position. Another factor in the southward adjustment is that this system is now unlikely to become strong/tall enough in the short-term to interact steering-wise with the lingering eastern Atlantic upper vorticity located to the north. It is clear that my previous outlook on this system had odds of tropical cyclone formation set too high... and in this update I have halved my peak odds of tropical cyclone formation to 20%. Due to current observations of the wave struggling with dry air and the current lack of computer model support showing development... the NHC has already dropped odds of tropical cyclone formation to 0%. I am reluctant to go that far in this update as this tropical wave could make a recovery while moving further away from Africa and into lower concentrations of dry Saharan air. In fact the tropical wave tagged as area of interest #28 in this update went through a similar situation in the days past... initially struggling offshore of Africa and then later recovering. By 120 hours the potential for development becomes more murky with some upper vorticity getting cut-off from Earl's remnant system as an upper ridge builds over the western Atlantic (more info on this upper wind pattern was discussed in the above area of interest #28 section). This tropical wave has potential to near the south side of this upper vorticity where upper westerly shearing winds would be present... and so I end the 5-day forecast period with lower 10% odds of tropical cyclone formation.

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

IOH 24 Hr Outlook (0000Z Sep 15)...20% chance of tropical cyclone formation (eastern tropical Atlantic near 14.5N-31W)

IOH 48 Hr Outlook (0000Z Sep 16)...20% chance of tropical cyclone formation (eastern tropical Atlantic near 15.5N-36W)

IOH 72 Hr Outlook (0000Z Sep 17)...20% chance of tropical cyclone formation (eastern tropical Atlantic near 16N-41W)

IOH 96 Hr Outlook (0000Z Sep 18)...20% chance of tropical cyclone formation (central tropical Atlantic near 17N-46W)

IOH 120 Hr Outlook (0000Z Sep 19)...10% chance of tropical cyclone formation (central tropical Atlantic near 18N-51W)


AREA OF INTEREST #30...An additional tropical wave of low pressure currently over western Africa... trailing behind area of interest #29... has become notable over the last several hours with a tremendous area of thunderstorm activity. Favoring this tropical wave as it moves into and across the eastern tropical Atlantic at 48+ hours is the persistent tropical upper ridge in the region featuring low shear and upper outflow. However I continue to cap peak odds of tropical cyclone formation to 20% due to the current lack of computer model support showing development... and will have to wait and see how this wave later interacts with the dry Saharan air before suggesting any higher odds of tropical cyclone formation. Specifically as seen time and again this hurricane season... conditions for tropical development in the eastern tropical Atlantic have been unfriendly due to dry air. However also noting that I have ramped up to the 20% odds a little faster in this update to account for the current tremendous area of thunderstorms this tropical wave has developed.

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

IOH 24 Hr Outlook (0000Z Sep 15)...0% chance of tropical cyclone formation (west coast of Africa near 10.5N-15.5W)

IOH 48 Hr Outlook (0000Z Sep 16)...15% chance of tropical cyclone formation (eastern tropical Atlantic near 11N-20.5W)

IOH 72 Hr Outlook (0000Z Sep 17)...20% chance of tropical cyclone formation (eastern tropical Atlantic near 11.5N-25.5W)

IOH 96 Hr Outlook (0000Z Sep 18)...20% chance of tropical cyclone formation (eastern tropical Atlantic near 12N-30W)

IOH 120 Hr Outlook (0000Z Sep 19)...20% chance of tropical cyclone formation (eastern tropical Atlantic near 12.5N-35W)


...COMPUTER MODEL SUMMARY...

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


1200Z (Sep 13) CMC Model Run...

**For area of interest #28... low pressure spin on tropical wave dissipates as it moves across the northern Lesser Antilles at 72 hours... tropical wave redevelops a low pressure spin over western Cuba at 168 hours.

**For area of interest #29... no development shown

**For area of interest #30... tropical wave becomes a short-lived tropical low south of the Republic of Cabo Verde Islands at 96 hours after which time the tropical low opens back to a wave with no development shown in the long range.


1200Z (Sep 13) ECMWF Model Run...

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

**For area of interest #29... no development shown

**For area of interest #30... no development shown


1800Z (Sep 13) GFS Model Run...

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

**For area of interest #29... no development shown

**For area of interest #30... no development shown


1800Z (Sep 13) NAVGEM Model Run...

**For area of interest #28... tropical cyclone formation suggested east of the northern Lesser Antilles near 16.5N-59W at 66 hours... passes over the northern Lesser Antilles at 90 hours as a strengthening tropical storm... passes just north of the Virgin Islands and Puerto Rico at 114 hours while strengthening into a hurricane... hurricane located near 19.9N-66N at 120 hours

**For area of interest #29... no development shown

**For area of interest #30... no development shown

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