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 #121

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


...THURSDAY OCTOBER 6 2022 2:39 AM EDT...

Tropical Depression Twelve lingers in the eastern tropical Atlantic... unable to strengthen into a tropical storm under southwesterly wind shear. See Tropical Depression Twelve section below for more information on this system. Elsewhere in the Atlantic basin... monitoring a couple of areas of interest for signs of future tropical development:

(1) The current tropical wave of low pressure crossing northeastern Venezuela and the southeastern Caribbean Sea continues to show signs of vigor. It is expected to develop into a tropical cyclone to head toward Nicaragua by this weekend. In the short-term this tropical wave will affect northwestern Venezuela... the ABC Islands (Aruba Bonaire and Curacao)... and northern Colombia for the remainder of this week regardless of tropical cyclone formation or not. See area of interest #35 section below for more information.

(2) See area of interest #37 section below for an update on the Caribbean surface trough of low pressure offshore of Honduras.


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 #35 and #37 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 TWELVE...The tropical depression in the eastern tropical Atlantic continues to remain sheared courtesy of the nearby upper vortex to its northwest that is imparting upper southwesterly flow across the depression. The upper flow is keeping the thunderstorm bursts of the depression east of its swirl center... however the thunderstorm activity remains near enough the swirl center to maintain the technical definition of this system as a tropical depression. The depression's center is a tad southwest of my prior forecast track... and my updated one is nudged accordingly. The depression has been floating northwest instead of west around the Atlantic surface ridge as the south side of the ridge has been kept weak by the divergent east side of the upper vortex which is keeping surface pressures low. However the strength of the central Atlantic upper ridge is expected to stretch the upper vortex into a string of upper vorticity such that it loses its focused eastern divergence zone... resulting in the south side of the Atlantic surface ridge recovering which in turn will push the depression more westward. I forecast the depression to dissipate by 48 hours as the forecast track brings the depression directly into the upper vortex where shear is higher.


In the long-range... will watch the remnants of the depression which will continue west-northwest to the other side (north side) of the of the elongating upper vortex and underneath the southwest side of the central Atlantic upper ridge where shear will be lower and upper outflow will be higher. This may allow for the remnants of the depression to re-generate. In this update cycle... noting the models have backed off on this idea. If this changes in future update cycles... or if future observation warrant... the remnants of the depression would be re-introduced as an area of interest on this blog complete with a forecast.

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

0 Hr Position (0000Z Oct 6)...35 mph maximum sustained wind tropical depression centered at 17.7N-32.5W

IOH 24 Hr Forecast (0000Z Oct 7)...35 mph maximum sustained wind tropical depression centered at 20N-35W

IOH 48 Hr Forecast (0000Z Oct 8)...Remnant trough near 20.5N-38W


AREA OF INTEREST #35...The vigorous tropical wave of low pressure which crossed the southern Lesser Antilles... and continues crossing northeastern Venezuela and the southeastern Caribbean Sea... has moved past the westerly shear on the south side the nearby upper vortex. Although the wave is in a lower shear environment... shear is not totally absent as the wave is exposed to upper northerly flow occurring on the south side of the current northern Caribbean upper ridge axis. The light northerly shear has kept the thunderstorm activity suppressed toward the south... which appears to have kept the broad area of surface low pressure rotation toward the south where the thunderstorm latent heat release driven upper outflow has been more effective at keeping surface pressures lower. The updated forecast track in the outlook below is adjusted southward based on the current position of the wave's area of rotation. The window for this system to make slight northward progress in its westward track will close by 48+ hours as the surface ridge weakness associated with the broad western Atlantic frontal low pressure and its upper vortex will close... as the upper vortex and frontal low pressure area lift away to the northeast while kicked by a major upper trough to settle into eastern North America. The western convergence zone of the major upper trough is also expected to build a rather strong surface ridge over the United States... enough to keep the track of this system on a westward or perhaps west-southwest heading toward Nicaragua by 4+ days. The outlook below is ended by day 4 as this system could very well cross Nicaragua and enter the eastern Pacific by day 5 where it could become a concern there... this site is dedicated to Atlantic tropical activity.


Regarding odds of tropical cyclone formation...the updated forecast track increases land interaction with northern Venezuela and northern Colombia and so I have lowered my short-term odds of tropical cyclone formation to 70%... now in agreement with the latest NHC tropical weather outlook as of this writing. I also agree with the NHC outlook's higher 90% odds in the longer range as land interaction reduces once this system moves past the Guajira peninsula and into more open south-central Caribbean waters. The rather high longer-term development odds are supported by the global models... which despite the light northerly wind shear are essentially in unanimous agreement on developing this system in the south-central Caribbean. If this tropical wave maintains its current signs of organization and models continue to remain in their unanimous agreement... I will issue a tropical cyclone formation forecast in my next update with specific track and intensity forecast points. It also would not surprise me if this system becomes a tropical cyclone a little sooner and in the waters just offshore of Venezuela or Colombia... which would definitely require a track and intensity forecast by my next update.


Regarding impacts to land areas:

(1) Regardless of short-term tropical cyclone formation or not... heavy rainfall and gusty winds are expected for northwestern Venezuela... the ABC Islands (Aruba Bonaire and Curacao)... and northern Colombia through today and Friday. If this system manages to become a tropical storm during this timeframe... coastal sea swells in these areas will be more likely.

(2) Interests in Nicaragua should be carefully monitoring the progress of this system... preparations for tropical storm to hurricane-force wind and coastal sea swells for the east coast may be required starting Friday or Saturday. Heavy rainfall with flash flooding potential will be an additional hazard. Depending on the exact track and size of this system... heavy rains and gusty winds could also reach parts of Honduras... Costa Rica... or El Salvador by early next week.


Update as of 2 AM EDT... the NHC has raised short-term odds of tropical cyclone formation for this system from 70% to 80%. Long-term odds remain set at 90%.

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

IOH 24 Hr Outlook (0000Z Oct 7)...70% chance of tropical cyclone formation (between the northwest coast of Venezuela and ABC Islands near 11.5N-68.5W)

IOH 48 Hr Outlook (0000Z Oct 8)...80% chance of tropical cyclone formation (west coast of Guajira Peninsula of northern Colombia near 11.8N-72W)

IOH 72 Hr Outlook (0000Z Oct 9)...90% chance of tropical cyclone formation (south-central Caribbean Sea near 12N-77.5W)

IOH 96 Hr Outlook (0000Z Oct 10)...90% chance of tropical cyclone formation (east of the southern Nicaragua coast near 12N-82W)


AREA OF INTEREST #37...The Caribbean surface trough of low pressure offshore of Honduras is expected to drift southwest into Honduras as steering surface high pressure ridging persists to the northwest. This ridging will continue as a major upper trough settles into eastern North America... with the western convergence zone of the upper trough in turn re-enforcing the ridging. The surface trough has lost its thunderstorm activity... and its potential to become a short-lived tropical depression before moving into Honduras has declined. 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 7)...0% chance of tropical cyclone formation (northeast coast of Honduras near 15.8N-85W)


...COMPUTER MODEL SUMMARY...

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


1200Z (Oct 5) CMC Model Run...

**For Tropical Depression Twelve... weakens to a trough near 17.5N-35W at 24 hours.

**For area of interest #35... tropical cyclone formation suggested just west of the Guajira peninsula of northern Colombia near 12.2N-73.5W at 60 hours... makes landfall on the north coast of Nicaragua at 108 hours potentially at hurricane strength... weakens to an inland tropical storm whose center reaches the central Nicaragua/Honduras border at 120 hours.

**For area of interest #37... no development shown


1200Z (Oct 5) ECMWF Model Run...

**For Tropical Depression Twelve... weakens to a remnant trough near 17.5N-40W by 48 hours.

**For area of interest #35... tropical cyclone formation suggested near 13.5N-78W at 72 hours... makes landfall on central Nicaragua coast as a top-end tropical storm at 96 hours... from landfall weakens to a remnant low which westward across northern Nicaragua and into El Salvador by 120 hours.

**For area of interest #37... no development shown


1800Z (Oct 5) GFS Model Run...

**For Tropical Depression Twelve... weakens to a trough near 18N-35.5W at 27 hours.

**For area of interest #35... tropical cyclone formation suggested on the west coast of the Guajira peninsula of northern Colombia at 51 hours... makes landfall on the Nicaragua/Honduras border at 114 hours potentially as a hurricane... located over eastern Honduras as a weakening inland tropical storm at 120 hours.

**For area of interest #37... no development shown


1800Z (Oct 5) NAVGEM Model Run...

**For Tropical Depression Twelve... weakens to a trough near 17.5N-35W at 18 hours.

**For area of interest #35... tropical cyclone formation suggested offshore of northwestern Venezuela near 13.5N-70.5W at 42 hours... makes landfall over eastern Honduras potentially as a hurricane at 108 hours... center moves west-northwest into the waters just offshore of north-central Honduras by 120 hours as a moderate/strong tropical storm.

**For area of interest #37... no development shown

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