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 #129

Updated: Oct 16

*******Note that forecast 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 OCTOBER 15 2022 4:00 AM EDT...

Tropical Storm Karl has weakened to a depression while nearing the Bay of Campeche coast of Mexico's Tabasco province... see Karl section below for an update on this tropical cyclone. Elsewhere... the potential for tropical development in the open central Atlantic is closing... see area of interest #38 section below for more information. See area of interest #40 section below for an update on the tropical wave of low pressure in the eastern Atlantic continuing to be monitored for signs of development.


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 #38 and #40 as the other numbers were used 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.


TROPICAL DEPRESSION KARL... While drifting southward in the eastern Bay of Campeche and toward the coast of Tabasco... Karl has not overcome the challenges of northerly shear being induced by the east side of an upper ridge cell approaching from mainland Mexico. The tropical storm has gradually faded on Friday and as of 11 PM EDT earlier this evening was downgraded to a tropical depression. What remains of Karl's thunderstorm activity as of this writing is displaced south of the center by the shear and occurring only in small pockets over parts of southeastern Mexico. The southward drift of Karl has been induced by the tropical cyclone being strong/tall enough to be dragged by the shearing northerly (southward-pushing) upper winds. At some point a turn to the west and perhaps northwest is anticipated as weakening Karl becomes shallower and decouples from the upper winds... resulting in a takeover of surface-layer steering. Also note that by 48 hours the anticyclonic core of the approaching upper ridge cell will overspread Karl... neutralizing its ability to steer Karl even if it were hypothetically strong/tall. The surface-layer steering will be controlled by the southwest quadrant of a surface ridge currently building over the southeastern US and behind the cold front that recently has entered the northern Gulf of Mexico... and also a frontal low to approach from the southwestern US and northern Mexico (frontal low supported by a small upper vortex that slides into the southwestern US from the Pacific). The question remains as to how soon Karl turns to the west and northwest while transitioning into a weaker/shallower feature. The sooner it turns to the west the more likely it can hang on just offshore of Veracruz through 72 hours... the later in turns to the west the more likely Karl will continue southward and inland and thus dissipate sooner as shown by the current NHC official forecast. Given that Karl has already weakened notably... I continue to opt for a sooner turn and keep Karl just offshore of Veracruz in my updated track forecast (also note their is a slight eastward adjustment to the track forecast due to Karl's current position... therefore a sooner turn to the west and northwest now also means Karl would stay just offshore instead of along the Veracruz coast). Also noting in the computer model summary section below the NAVGEM and GFS somewhat hinted at a sooner westward turn. Should Karl indeed stick around the Veracruz coast through 72 hours... it should be brought to an end by 96 hours as a southward-diving surface ridge... to be supported by the western convergence zone of an amplified upper trough to move across western Canada which will be diving south while merging with the west side of the current North American upper vortex... shoves Karl on a more westward track and further inland. Note that although Karl by 72+ hours will have tracked into upper westerlies on the north side of the regional upper ridge cell... the land interaction and dose of upper westerly shear should keep Karl weak/shallow such that Karl should have no chance to be dragged into the Gulf of Mexico at 96 hours by the upper westerlies.


Regarding intensity... Karl's currently poor satellite appearance suggests a downgrade to a remnant low is possible by the next 5 AM EDT NHC advisory... or in subsequent advisories to be issued later today... therefore my current intensity forecast now downgrades Karl to a remnant low in the next 24 hours. Normal protocol on this blog is to end the forecast when decay to remnant low status is expected. However noting that if Karl or its remnants manages to hang around coastal Veracruz or the waters just offshore as discussed in the previous paragraph... it could try to make a comeback around 48 hours as the anticyclonic core of the approaching upper ridge cell overspreads Karl and thus creates a haven of low wind shear. Therefore on this blog the forecast for the remnant low remains extended through 96 hours... in preparation for tropical cyclone formation probability outlooks in future updates in case Karl's remnants do try to make a comeback.


Regarding impacts to land areas:

(1) Heavy rainfall and flash flood risk... Karl or its remnants could produce pockets of heavy rainfall across southwestern Campeche... Chiapas... Oaxaca... Tabasco... and southeastern Veracruz through Sunday. At further east locations the flash flooding risk may end by this afternoon as Karl bends more west in track. By early this upcoming week... should Karl in fact linger as a northwestward-tracking remnant tropical low or weak tropical cyclone along/near the Veracruz coast... the flooding risk would shift toward northern Veracruz... Tlaxacala... Hildalgo... eastern San Luis... and southern Tamaulipas.

(2) Gusty winds... Karl has weakened below tropical storm force and all previous coastal tropical storm watches/warnings have been cancelled. I recommend that interests along coastal Tabasco and Veracruz that had previously prepared under prior watches and warnings should remain aware of this system in case Karl or its remnants do try to make a comeback as discussed above.

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

0 Hr Position (0000Z Oct 15)... 35 mph maximum sustained wind tropical depression centered in the eastern Bay of Campeche at 19.1N-92.8W

IOH 24 Hr Forecast (0000Z Oct 16)... Remnant low centered just offshore of the northwestern Tabasco coast at 18.9N-93.8W

IOH 48 Hr Forecast (0000Z Oct 17)... Remnant low centered just offshore of the Tabasco/Veracruz border region at 18.7N-95.2W

IOH 72 Hr Forecast (0000Z Oct 18)... Remnant low centered along the northern Veracruz coast at 20.2N-97W

IOH 96 Hr Forecast (0000Z Oct 19)... Dissipating inland over east-central Mexico near 21.5N-99.2W


AREA OF INTEREST #38... The broad surface trough of low pressure in the open central Atlantic... located in the vicinity of 32.5N-52.5W and previously supported by the eastern divergence zone of an upper trough in the region... has dissipated despite the regional reduction in shear and increase in upper divergence as the upper trough has amplified into a cut-off upper vortex. The CIMSS 850 mb vorticity product (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=) suggests that just above the surface that rotation continues in the region... therefore it is possible for surface spin to return to the region. However any surface spin that develops should quickly shift northwest around the north side of the upper vortex and southwest side of surface ridging that is persisting to the north... carrying it into waters temps below 26 deg C. Therefore tropical cyclone formation in this region has become unlikely... and this is my planned final statement on this area of interest on this blog.

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

IOH 24 Hr Outlook (0000Z Oct 16)...0% chance of tropical cyclone formation (central Atlantic near 37.5N-54W)


AREA OF INTEREST #40... The tropical wave of low pressure currently in the eastern tropical Atlantic continues to have an area of defined showers and thunderstorms... however has not made progress in developing further. Their remains some potential for the tropical wave to develop as the tropical upper ridge is forecast to continue expanding as the string of cool core upper vorticity to the north continues receding while weakening from its ongoing lack of access to high-latitude cold air... which will allow the tropical wave to be sheltered from shear in the days ahead. The Atlantic surface ridge to the north is forecast to remain weak due to the presence of area of interest (AOI) #38 in the shorter-term... followed by the development of another low pressure system east of Bermuda as a fragment of the current North American upper vortex moves offshore as an upper trough and supports the new low pressure area with its eastern divergence zone. As a result a sluggish west-northwest track is forecast for this tropical wave of low pressure (as opposed to a faster more westward motion which would occur if the Atlantic surface ridge stays intact). Note that the upper trough associated with AOI #38 has fractured into a small upper vortex near AOI #38 and a low-latitude upper trough northeast of the Lesser Antilles further south. Although this low-latitude upper trough may shift east toward the forecast track region of this tropical wave and hence potentially shear it at 48 hours... it is subsequently expected to weaken while remaining cut-off from high-latitude cold air and the return to a lower shear environment is possible by 72+ hours. Therefore I continue to forecast peak 5-day odds of tropical cyclone formation at 30%. I have not raised odds of development above the 30% due to the latest lack of computer model support showing development and as the wave has not made progress in developing further thus far... and have also lowered short-term odds of tropical cyclone formation as another way to account for the current lack of development progress.

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

IOH 24 Hr Outlook (0000Z Oct 16)... 0% chance of tropical cyclone formation (eastern tropical Atlantic near 9.5N-32.5W)

IOH 48 Hr Outlook (0000Z Oct 17)... 10% chance of tropical cyclone formation (eastern tropical Atlantic near 10.5N-35.5W)

IOH 72 Hr Outlook (0000Z Oct 18)... 20% chance of tropical cyclone formation (eastern tropical Atlantic near 11.5N-38.5W)

IOH 96 Hr Outlook (0000Z Oct 19)... 30% chance of tropical cyclone formation (eastern tropical Atlantic near 12.5N-41W)

IOH 120 Hr Outlook (0000Z Oct 20)... 30% chance of tropical cyclone formation (central tropical Atlantic near 13.5N-45W)


...COMPUTER MODEL SUMMARY...

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


1200Z (Oct 14) CMC Model Run...

**For Tropical Storm Karl... makes landfall at the western Tabasco coast at 18 hours... drifts southwest further inland and dissipates at the Tabasco/Veracruz border at 30 hours.

**For area of interest #38... no development shown

**For area of interest #40... no development shown


1200Z (Oct 14) ECMWF Model Run...

**For Tropical Storm Karl... makes landfall at the Tabasco/Veracruz border at 24 hours and dissipates shortly thereafter

**For area of interest #38... no development shown

**For area of interest #40... no development shown


1200Z (Oct 14) GFS Model Run...

**For Tropical Storm Karl... moves southwest to waters just offshore of the Veracruz/Tabasco border at 24 hours... afterwards weakens to a tropical depression that drifts westward... makes landfall at the southeast Veracruz coast at 45 hours shortly after which time it dissipates.

**For area of interest #38... no development shown

**For area of interest #40... no development shown


1200Z (Oct 14) NAVGEM Model Run...

**For Tropical Storm Karl... drifts southwes tto the waters offshore of the Veracruz/Tabasco border at 18 hours... turns west-southwest and makes landfall at the southeast Veracruz coast at 36 hours shortly after which time it dissipates.

**For area of interest #38... no development shown

**For area of interest #40... organizes into a tropical low near 9.8N-32.5W at 30 hours... tropical low weakens to a trough near 15N-38W at 108 hours

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