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 #127

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


...WEDNESDAY OCTOBER 12 2022 3:40 AM EDT...

Per special update #126A released earlier on Tuesday afternoon... Tropical Storm Karl has quickly formed in the Bay of Campeche. See Tropical Storm Karl section below for the latest outlook regarding potential impacts to parts of southeastern Mexico and east-central Mexico expected over the next 72 hours. Also noting in the long range that the remnant moisture of Karl may be spread northward into northeastern Mexico and southern Texas.


Also noting in special update #126A that the target time for this full update was for earlier this evening. However was not able to achieve an earlier update time as we continue to monitor potential for additional tropical development elsewhere in the Atlantic basin as follows:

(1) See area of interest #38 section below for an update on the surface trough of low pressure in the open central Atlantic... which may develop into an organizing subtropical or tropical disturbance later this week and into the weekend.

(2) A tropical wave of low pressure is currently emerging from the west coast of Africa with a vigorous but disorganized area of thunderstorm activity. Various model runs over the last few days suggest this wave may attempt to develop in the eastern tropical Atlantic as westerly shear in the region relaxes with the decay of the cool core upper vorticity in the region generating the shear... as the vortiicty remains cut-off from high latitude cold air. The long range outlook for this tropical wave does not appear positive for it as it will tend to move west-northwest in track toward the surface ridge weakness associated with area of interest (AOI) #38... and hence toward shearing upper westerlies to be induced by the upper trough supporting AOI #38. Should the wave show signs of organizing as shear reduces in the short-term... will add it as an area of interest for tropical development in future updates.


TROPICAL STORM KARL... Karl has rapidly formed over the last 24 hours from the Bay of Campeche disturbance that materialized from the north half of Julia's remnant outer circulation. Since formation the center of circulation has been observed to drift northwest toward the surface ridge weakness associated with the frontal cyclone currently maturing over North America. Noting that Karl has formed further west of prior forecasts... as a result the models now see that Karl will be too far from the frontal cyclone's cold front to dive into the north-central Gulf of Mexico such that the models no longer have the front drag Karl east and southeast. Instead after 24 hours... the latest model consensus shows Karl simply getting pushed southwest toward the north coast of Veracruz by the surface ridge to build behind the cold front. My updated forecast below... and also the NHC official forecast... show this idea. I suggest a northwest track for the landfalling tropical storm and subsequent inland remnant low between 48 and 72 hours while Karl moves toward a surface ridge weakness to develop over the southwestern United States in association with the eastern divergence zone of an upper vortex to slide into the region.


Regarding intensity... Karl looks more like a sheared tropical storm in the latest satellite pictures with the thunderstorms now displaced in a comma-shaped feature to the northeast of the center. The distance between Karl and shearing mid-latitude upper westerlies has decreased due to Karl's northwest track toward those upper winds... and as the southern reaches of the upper trough associated with the developing North America frontal cyclone has expanded the field of upper westerlies in a southward direction toward Karl. I agree with the NHC on only gradually strengthening Karl over the next 24 hours as the shear is not expected to increase further... but at the same time should be moderate enough to hamper rapid development of Karl. At 48+ hours... the frontal cyclone and associated upper trough are expected to begin a gradual northeastward retreat which may allow the shear to relax. Therefore I forecast additional gradual strengthening of Karl toward a higher-end tropical storm through 48 hours... higher than the NHC official forecast as of this writing. I chose gradual instead of more rapid development for this timeframe as it is still uncertain how much of the cool dry air to enter the northern Gulf of Mexico and behind the frontal cyclone's cold front will be ingested by Karl.


Regarding impacts to land areas:

(1) Westerly shear has pushed stronger thunderstorm activity of Karl toward Campeche province and western parts of the Yucatan province. Heavy rainfall with flash flooding potential cannot be ruled out in this region over the next 24 hours... after which time the rainfall potential should subside as Karl drifts westward further away from the eastern Bay of Campeche region and as shear potentially relaxes.

(2) If the current forecast holds... the impact potential of Karl to Tabasco... Oaxaca... and Chiapas has reduced. However interests in Tabasco should remain on guard for any potential forecast shifts... for example Karl becoming more entangled with the cold front to enter the northern Gulf of Mexico such that the front drags Karl southeastward toward the south-central Bay of Campeche.

(3) The potential for a heavy rainfall event starting Thursday evening is increasing for Veracruz... Tlaxcala... Hidalgo... and eastern San Luis. Flash flooding and mudslides are a possiblity. The potential for flash flooding heavy rains to shift northward across Tamaulipas and into southern Texas by Friday and the weekend is increasing as the moisture from Karl's remnants becomes pulled northward by a frontal low pressure area to be supported across the south-central and southwestern United States by an upper vortex shifting eastward into the region.

(4) Interests across the northern Veracruz coastline remain under a tropical storm watch as of this writing. I recommend interests here prepare now for an increasing likelihood of tropical storm force gusts with some damage potential and coastal surf to arrive by Thursday evening. As such preparations should be completed by Thursday morning.

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

0 Hr Position (0000Z Oct 12)...40 mph maximum sustained wind tropical storm centered in the western Bay of Campeche at 20.5N-94.9W

IOH 24 Hr Forecast (0000Z Oct 13)...50 mph maximum sustained wind tropical storm centered in the southwestern Gulf of Mexico at 21.5N-96W

IOH 48 Hr Forecast (0000Z Oct 14)...60 mph maximum sustained wind tropical storm centered just offshore of northern Veracruz at 20.5N-97W

IOH 72 Hr Forecast (0000Z Oct 15)...Remnant low located over northern Veracruz and centered at 21.2N-98.5W


AREA OF INTEREST #38... The broad surface trough of low pressure in the open central Atlantic... currently located in the vicinity of 30N-55W... is now being supported by the eastern divergence zone of an upper trough that has arrived into the northwest Atlantic from eastern Canada. The associated thunderstorm activity is disorganized and wind shear levels are currently too high to support tropical development. However the warm sector of the frontal cyclone currently developing over North America is expected to build an amplifying western Atlantic upper ridge... which in turn will cause the upper trough to amplify which will reduce shear and increase the supporting upper divergence over the surface trough. Therefore will be watching for the surface trough to potentially evolve into an organizing subtropical or tropical disturbance to be supported by the amplifying upper trough. The forecast track below is adjsuted based on the current position of the surface trough and through 72 hours shows an eastward shift of the surface trough corresponding to an eastward shift of the supporting upper trough. The eastward track of the upper trough and disturbance is slower in this update as the latest model data suggests a more amplified and slower moving upper trough in this update cycle. By 96+ hours the amplifying western Atlantic upper ridge is forecast to further amplify the upper trough into a cut-off vortex that moves southeastward and away... while at the same time the current eastern US surface ridge will have shifted to a position due north of this system. As a result the forecast track in the updated outlook below shows a northward hook around the east side of the cut-off upper vortex between 72 and 96 hours... and then a northwest acceleration around the southwest side of the surface ridge between 96 and 120 hours after the upper vortex moves out of the region. Conditions for development will remain favorable through 120 hours as the northwest track moves this system under the low shear and upper outflow environment of the amplifying west Atlantic upper ridge. My peak odds of tropical cyclone formation for this area of interest remains at a low 10% as models do not show this system developing as of this writing.

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

IOH 24 Hr Outlook (0000Z Oct 13)...0% chance of tropical cyclone formation (central Atlantic near 30N-55W)

IOH 48 Hr Outlook (0000Z Oct 14)...10% chance of tropical cyclone formation (central Atlantic near 30N-54W)

IOH 72 Hr Outlook (0000Z Oct 15)...10% chance of tropical cyclone formation (central Atlantic near 31N-52.5W)

IOH 96 Hr Outlook (0000Z Oct 16)...10% chance of tropical cyclone formation (central Atlantic near 33N-52W)

IOH 120 Hr Outlook (0000Z Oct 17)...10% chance of tropical cyclone formation (central Atlantic near 35.5N-54W)


...COMPUTER MODEL SUMMARY...

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


1200Z (Oct 11) CMC Model Run...

**For Tropical Storm Karl... moves northwest toward waters just offshore of northern Veracruz through 36 hours... drifts south-southwest into the north coast of Veracruz at 60 hours and dissiptes shortly thereafter.

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

**South fragment of current upper trough rolling across western North America moves into the western Atlantic in the long range and generates a broad surface low southeast of Bermuda near 30N-61W at 144 hours... while drifitng north surface low consolidates into a tropical cyclone near 30.5N-60.5W at 168 hours.

**Tropical wave currently over far western Africa emerges from the west coast of Africa at 30 hours... organizes into a tropical low near 9N-25W at 66 hours... tropical low moves west-northwest toward surface ridge weakness associated with area of interest #38 and weakens to a surface trough near 14N-38.8W at 168 hours.

**Cold front across the western United States... driven by an additional upper trough that moves into western Canada/northwestern US and upper vortex that moves into the southwestern United States... moves into the western Gulf of Mexico at 156 hours... cold front evolves into broad tropical low pressure supported by outflow of tropical upper ridge in the region at 168 hours that covers the Bay of Campeche... southeastern Mexico... northern Guatemala... and Belize.


1200Z (Oct 11) ECMWF Model Run...

**For Tropical Storm Karl... moves northwest to 21N-96W by 24 hours... drifts south-southwest into the central coast of Veracruz and dissipates by 72 hours.

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

**South fragment of current upper trough rolling across western North America moves into the western Atlantic in the long range and generates a broad surface low southeast of Bermuda near 30N-60W at 144 hours

**Cold front across the western United States... driven by an additional upper trough that moves into western Canada/northwestern US and upper vortex that moves into the southwestern United States... moves into the western Gulf of Mexico at 144 hours... cold front evolves into broad tropical low pressure supported by outflow of tropical upper ridge in the region at 168 hours that covers the western Gulf of Mexico and east-central Mexico.


1800Z (Oct 11) GFS Model Run...

**For Tropical Storm Karl... moves northwest to 20.5N-96W by 30 hours... drifts south into southeastern Vereacruz through 51 hours and dissipates at this location by 63 hours.

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

**South fragment of current upper trough rolling across western North America moves into the western Atlantic in the long range and generates a broad surface low just east-southeast of Bermuda at 105 hours... moves northeast and consolidates into a possible tropical cyclone near 33N-60W at 120 hours

**Cold front across the western United States... driven by an additional upper trough that moves into western Canada/northwestern US and upper vortex that moves into the southwestern United States... moves into the western Gulf of Mexico at 147 hours... cold front evolves into broad tropical low pressure supported by outflow of tropical upper ridge in the region at 168 hours that covers the Bay of Campeche... southeastern Mexico... northern Guatemala... and Belize.


1800Z (Oct 11) NAVGEM Model Run...

**For Tropical Storm Karl... moves northwest to 23N-96W by 30 hours... drifts south-southwest into the northern Veracruz coast through 78 hours where it weakens to a remnant trough with the trough dissipating by 96 hours.

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

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