*******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 NOVEMBER 5 2022 4:55 AM EDT...
The Atlantic tropics remain exceptionally and unusually active for November due to multiple areas of interest as follows:
(1) Tropical Depression Lisa is forecast to meander and dissipate over the western Bay of Campeche later today due to increasing wind shear... see Lisa section below for more information.
(2) A series of disturbances with tropical characteristics are expected to cyclonically orbit around a cut-off upper vortex to become established in the vicinity of the Bahamas and northern Caribbean. See area of interest #44 section below for more information on the primary subtropical disturbance that is expected to be generated by upper divergence on the east side of the vortex. Area of interest #45 currently located east of Bermuda is now forecast to consolidate further north and away from area of interest #44 while area of interest #46 in the southern Caribbean Sea has remained weak. This reduces the chances that areas of interest #45 and #46 merge with #44... decreasing the potential for area of interest #44 to become disorganized and hence increasing its potential to become a subtropical cyclone that later swings toward the northwest Bahamas and Florida peninsula.
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 #44 to #46 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 LISA... As expected Lisa continued west-northwest into the western Bay of Campeche under the influence of the deep-layer ridge to the northeast. As of late Lisa has meandered due to weak steering currents due south of the surface ridge weakness associated with the current central US cold front. Recent nighttime infrared satellite loops suggest the surface cloud swirl of Lisa may be reversing into an eastward drift due to the eastward push of the cold front. My updated forecast track below suggests Lisa continuing on an eastward drift over the next 12 hours... followed by another reversal back toward the west between 12 and 24 hours under the influence of a weak surface ridge to build and pass to the north of Lisa (a surface ridge to be created by the western convergence zone of the cold front's upper trough). Essentially this results in Lisa arriving back to its current position by 24 hours. This is also in agreement with the latest model consensus that shows Lisa meandering aimlessly at its current location until dissipation. Southerly shear between the west side of the ongoing western Caribbean upper ridge cell and out ahead of the upper trough associated with the central US cold front has kept the thunderstorm activity pulled northward from Lisa's surface spin. At one point the sheared-off thunderstorm activity featured Lisa's mid-level rotation which became sepearated from the surface spin thanks to the shear... and this mid-level rotation has since dissipated. As of this writing there is not much thunderstorm activity left in association with Lisa... and the shear is expected to worsen and take a more westerly direction as the south side of the upper trough associated with the central US cold front nears and increases the upper westerly flow in Lisa's envirionment... this is why dissiaption is anticipated in the next 24 hours.
Because the direction of the wind shear is keeping Lisa's thunderstorm activity away from Tabasco and southern Veracruz... impacts to land areas going forward are not anticipated.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (0000Z Nov 5)... 30 mph maximum sustained wind tropical depression centered over the western Bay of Campeche at 19.5N-95.5W
IOH 24 Hr Forecast (0000Z Nov 6)... Remnant low centered over the western Bay of Campeche at 19.5N-95.5W
AREA OF INTEREST #44... Over the last 36 hours... an upper trough that was near coastal North Carolina has been pushed southeastward to a position just northeast of the Bahamas and has also amplified all due to the amplifying upper layer of an unseasonably warm deep-layer ridge materializing over eastern North America and northwest Atlantic. The eastern divergence zone of this upper trough is currently producing a growing area of showers and thunderstorms across the eastern Caribbean... the northeastern Caribbean Islands from the Dominican Republic to Lesser Antilles... and western Atlantic waters to the east of the eastern Bahamas. The upper trough's divergence zone has also spawned a surface trough of low pressure in the eastern Caribbean due south of the Dominican Republic. As the aforementioned deep-layered ridge continues to mature... the upper trough is forecast to become a cut-off upper vortex... with the eastern divergence zone of the vortex forecast to trigger a subtropical disturbance just north of the northeastern Caribbean Islands over the next 48 hours. After formation... the subtropical disturbance is expected to then track north around the east side of the upper vortex... then curve west toward the northwestern Bahamas and Florida peninsula while steered between the north side of the upper vortex and south side of the deep-layer ridge. The westward swing in track is expected to continue through day 5 as another unseasonably warm deep-layer ridge develops over Canada in the warm sector of a vigorous frontal system to develop over the western US. The Canadian ridge is also expected to trap the south fragment of the current central US upper trough near Lisa in the eastern Gulf of Mexico... with this energy potentially merging with the west side of the upper vortex to re-enforce the upper vortex which will all the more help promote the westward track of this system. Between 72 and 96 hours... the westward track is forecast to slow as the curernt upper trough over the west Canadian coast will be heading into the northwest Atlantic where it creates a break between the current steering deep-layer ridge and the next deep-layer ridge to build over Canada. The forward speed picks up again between 96 and 120 hours once the Canadian deep-layer ridge takes over the steering.
Regarding odds of subtropical cyclone formation... I agree with the NHC increasing odds of developemnt to 60% through day 5 as the more respecpatble GFS is now onboard with the CMC and NAVGEM on showing subtropical cyclone formation. If this continues... and/or if the ECMWF joins... will be raising development odds even further in future updates. With the latest outlook... confidence is increasing that a large subtropical circulation will develop due to the size of the parent upper vortex's divergence zone. Thunderstorms in the circulation will be supported by water temps above 26 deg C... and will also be able to stay stacked vertically in a low shear environment caused by deep-layer cyclonic flow caused by the combo of the surface subtropical circulation and upper vortex... potentially allowing for the formation of a fully tropical core to the subtropical circulation that establishes warm anticyclonic outflow below the upper vortex and supported by the thunderstorm latent heat release. Should this occur... the transition to a strong fully tropical storm or hurricane could occurr by day 5. Regarding impact to land areas:
(1) A prolonged period of heavy rainfall with flooding potential is possible over the next few days for the Dominican Republic... Puerto Rico... the Virgin Islands... and the Lesser Antilles.
(2) Due to the large outer circulation of this system... a large area of wind blowing toward shore could produce notable coastal surf for the northwestern Bahamas as well as the southeast US coast from the Carolinas to east coast of Florida by Wednesday and Thursday. Gusty winds could also spread onshore during this timeframe.
(3) Should a fully tropical core become established as described above... more significant wind and coastal storm surge could affect the northwestern Bahamas and Florida peninsula by Thursday and Friday. I recommend interests here should be aware of this system and monitor the latest forecast trends with this system in the days ahead.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Nov 6)... 0% chance of subtropical cyclone formation (northeast of the Dominican Republic and north-northwest of Puerto Rico near 21N-66.5W)
IOH 48 Hr Outlook (0000Z Nov 7)... 20% chance of subtropical cyclone formation (western Atlantic near 24N-66.5W)
IOH 72 Hr Outlook (0000Z Nov 8)... 60% chance of subtropical cyclone formation (western Atlantic near 26N-71W)
IOH 96 Hr Outlook (0000Z Nov 9)... 60% chance of subtropical cyclone formation (western Atlantic near 27N-72.5W)
IOH 120 Hr Outlook (0000Z Nov 10)... 60% chance of subtropical cyclone formation (north of the northwestern Bahamas and east of the Florida peninsula near 27.5N-77.5W)
AREA OF INTEREST #45...The surface frontal low pressure area in the open Atlantic and currently well east of Bermuda over the last 36 hours has undergone some changes that require notable changes to its forecast. While the original surface circulation has been pushed south toward 27.5N-59W by the deep-layer ridge to the west of this system... the surface circulation has also expanded northeastward to 31N-52.5W which results in an southwest-northeast elongated circulation. The change in the surface circulation is due to changes with the upper trough fragment supporting the circulation. The upper trough fragment is a south fracture of the large scale upper trough interacting with Martin's remnant cyclone... and it has been fractured off due to the building upper layer of the deep-layer ridge while also taking on a southwest-northeast tilt due to the amplification of the deep-layer ridge. This explains the southwest-northeast tilt to the supportive eastern divergence zone of this upper trough fragment which in turn explains the elongation of the surface circulation. The northeast end of the end of the elongated surface circulation appears to be doing quiet well from a tropical perspective... establishing a better defined rotation featuring thunderstorms in its northern semicircle with associated latent heat release driven warm core upper outflow occuring to the east of the upper trough. The models have now trended with developing the northeast end of this system... requiring a notable northward shift in the forecast track. Due to the thunderstorms and associated warm outflow... I have upgraded this system from subtropical to tropical in this update cycle and have raised odds of tropical cyclone formation to 60% for the next 24 hours.
The updated forecast track for this system is anticyclonically curving around the aforementioned deep-layer ridge as the ridge passes to the north of this system... with this system ultimately curving eastward in the long range (72+ hours) in the flow ahead of a high-latitude upper trough to approach from its current position over the west coast of Canada. I drop odds of tropical cyclone formation from the 60% peak with time as the track takes this system into increasingly cooler water below 26 deg C... dropping the odds of development to 0% by 96 hours once this system is overran by the cold front of the high-latitude upper trough. Despite water temps below 26 deg C in the 48 to 72 hour range... I still have odds above 0% as the divergence zone of this system's parent upper trough fragment may aid in thunderstorm generation. Some of this parent upper trough will be ingested by the north side of the upper vortex to be associated with area of interest #44... with what remains of the parent upper trough potentially getting pushed into this system by the approaching high-latitude upper trough in 72+ hours... potentially resulting in an early increase in westerly wind shear over this system especially if most of the parent upper trough escaped absoprtion into area of interest #44 which would leave a good chunk of it to get pushed into this system. The potential early increase in shear is another reason why I continuously drop development odds after the 24 hour mark.
This system has potential to produce coastal surf to the island of Bermuda over the next 48 hours should tropical cyclone formation occur. I recommend interests here be aware of this system as any westward shift in the forecast track would bring this system very close to or over the island... for example if the high-latitude upper trough discussed in the previous paragraph does not quiet dig as far south as currently forecast thus delaying the northward turn of this system.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Nov 6)... 60% chance of tropical cyclone formation (east of Bermuda near 31N-57W)
IOH 48 Hr Outlook (0000Z Nov 7)... 50% chance of tropical cyclone formation (just east of Bermuda near 32.5N-61W)
IOH 72 Hr Outlook (0000Z Nov 8)... 40% chance of tropical cyclone formation (northwest Atlantic near 37N-60.5W)
IOH 96 Hr Outlook (0000Z Nov 9)... 0% chance of tropical cyclone formation (north Atlanitc near 41N-46W)
AREA OF INTEREST #46...Shower and thunderstorm activity in the southern Caribbean Sea has become weaker and more dispersed over an east-west elongated area of low-level vorticity seen in the CIMSS 850 mb vorticity product (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). The low-level vorticity (surface low pressure) and activity is supported by split flow upper divergence between the current western Caribbean upper ridge cell and current upper trough associated with area of interest #44. So far no tropical disturbance has solidified in the region... and the GFS model no longer forecasts this to occur. The low-level vorticity of this system will be flung northeastward toward the northeastern Caribbean Islands while ingested by the deep-layer cyclonic flow of area of interest #44... however I have dropped odds of tropical cyclone formation to 0% in this update as no disturbance has formed so far. Should the northeasward-moving vorticity later kick off a tropical disturbance... will re-introduce this system as an area of interest in future updates. For now... this is my planned final statement on this disturbance on this blog.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Nov 6)... 0% chance of tropical cyclone formation (southern Caribbean and just northwest of the Guajira peninsula of Colombia near 12.5N-73.5W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z (Nov 4) CMC Model Run...
**For Tropical Depression Lisa... dissipates just offshore of southern Veracruz over the next 24 hours.
**For area of interest #44... surface low forms just southeast of the Dominican Republic and just southwest of Puerto Rico at 42 hours... center of the broad surface low lifts north and passes between the Dominican Republic and Haiti at 48 hours... while curving north-northwest in track subtropical cyclone formation suggested near 28N-72W at 96 hours... subtropical cyclone turns west to west-southwest under influence of strong surface ridge expanding from Canada with the center of the cyclone just northeast of the northwestern Bahamas at 120 hours.
**For area of interest #45... frontal low establishes a better defined center near 29N-59.5W at 30 hours... weakens to a surface trough just southeast of Bermuda and near 30N-64W at 54 hours... westward moving surface trough subsequently loses its identity to area of interest #44 developing to the south.
**For area of interest #46... no development shown
0000Z (Nov 4) ECMWF Model Run...
**For Tropical Depression Lisa... while meandering just offshore of southern Veracruz dissipation forecast over next 36 hours.
**For area of interest #44... no development shown while becoming too broad and disorganized while absorbing areas of interest #45 and #46.
**For area of interest #45... no development shown
**For area of interest #46... no development shown
1800Z (Nov 4) GFS Model Run...
**For Tropical Depression Lisa... while meandering just offshore of southern Veracruz dissipation forecast over next 36 hours.
**For area of interest #44... surface low forms near 21N-66W at 42 hours... subtropical cyclone formation forecast near 25N-70W at 66 hours... cyclone continuously strengthens while swining west toward the northwestern Bahamas and reaches 27.5N-77.5W at 120 hours.
**For area of interest #45... northeast side of broad frontal low pressure system quickly consolidates and becomes a tropical cyclone near 32N-55.5W at 30 hours... while only gradually weakening over cooler waters the tropical cyclone conntinues west-northwest to 33.5N-59.8W through 54 hours... upper trough to approach from its current west Canada coast position recurves the tropical cyclone northward then northeastward with cold front driven by the upper trough causing a loss in tropical characteristics while cyclone located near 39N-57.5W at 84 hours... cyclone loses identity on the cold front while located near 41.5N-42W at 102 hours.
**For area of interest #46... no development shown
1800Z (Nov 4) NAVGEM Model Run...
**For Tropical Depression Lisa... while meandering just offshore of southern Veracruz dissipation forecast over next 18 hours.
**For area of interest #44... broad surface low forms near 20.8N-65W at 48 hours... subtropical cyclone formation suggested near 23.5N-66.5W at 60 hours... cyclone continuously strengthens while swining west and reaches 29.5N-75W at 120 hours.
**For area of interest #45... frontal low establishes a better defined center near 30N-57.5W at 18 hours...weakens to a trough east of Bermuda while located near 32N-62W at 60 hours... upper trough to approach from its current west Canada coast position brings cold front across northwest Atlantic which absorbs the surface trough while its located near 37.5N-59.8W at 84 hours.
**For area of interest #46... no development shown
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