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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 2024 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #37

Writer's picture: NCHurricane2009NCHurricane2009

Updated: Jul 9, 2024

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


...UPDATE...WEDNESDAY JULY 10 2024 12:40 AM EDT...

The birdseye view chart for this post was initially released without the surface and upper air charts included... to ensure the post was released in a timely manner. The birdseye view chart is now updated to include the surface and upper air charts.


...TUESDAY JULY 9 2024 5:50 PM EDT...


See remnants of Beryl section below for an update on the remnant frontal low of the former tropical storm now moving northeastward across the interior eastern United States. See area of interest #10 section below for an update on the tropical wave of low pressure that has moved from the Yucatan peninsula... across the Bay of Campeche... and will soon be making landfall over northern Veracruz.


Elsewhere... computer models are picking up on the idea that the tail end of the surface front attached to ex-Beryl has potential to evolve into a surface tropical disturbance in the vicinity of coastal South Carolina in about 48 hours while taking advantage of an island of low shear and anticyclonic upper outflow between the upper trough supporting ex-Beryl to the northwest and central Atlantic upper vorticity that will be approaching from the east. It is possible the disturbance remains quasi-stationary for some time over coastal South Carolina while sandwiched between the Atlantic surface ridge to the east and surface ridge building in the wake of ex-Beryl to the northwest (suggestion from 0000Z ECMWF)... or slips norhteastward parallel to the Carolina coast and then into offshore northwest Atlantic waters in a narrow surface ridge weakness induced by the divergence zone of some of the eastern upper vorticity as some of that vorticity potentially gets pulled norhtward into the upper trough tied to ex-Beryl (suggestion from 1200Z CMC)... or slips westward into the interior southeastern United States without further development as the surface ridge building behind ex-Beryl potentially takes over the steering (suggestion by 1200Z GFS). Currently not declaring a new tropical area of interest for the coastal Carolinas until there is better agreement among the models... or alternatively if future observations of satellite and radar data warrant... will be keeping an eye on this region in the days ahead.


REMNANTS OF BERYL... Over the last 24 hours Tropical Storm Beryl has transitioned into a non-tropical frontal low supported by divergence on the east side of the current central North America upper trough... with the surface center of circulation moving northeastward from eastern Texas and into the eastern Missouri/Arkansas border. Over the next 72 hours the remnant frontal low is expected to continue northeastward into the eastern Great Lakes and interior southeastern Canada... after which time the upper trough supporting ex-Beryl and ex-Beryl itself loses its identity while merging with a larger frontal system and upper trough sliding across northern Canada. Based on the latest radar presentation of ex-Beryl... a band of heavy rainfall has setup in the northwest half of the circulation while the southeast side features pockets of thunderstorms... some of which are severe and tornadic... with the severe thunderstorms being aided by vertical wind shear induced by the surface southerly flow on ex-Beryl's east side not being aligned with the upper southwesterly flow ahead of the aforementioned central North America upper trough. The northwestern band of heavy rainfall is positioned over northeastern Missouri... Illinois... northern Indiana... southern Michigan... and northern Ohio... and will be pivoting northeastward into southeastern Ontario and southwestern Quebec within the next couple of days... flash flooding from the heavy rainfall cannot be ruled out in this region. For the severe thunderstorms on the southeast side of ex-Beryl... as of this writing a tornado watch is in effect for north-central Tennessee... western and central Kentucky... southern Illinois... southern Indiana... and the southwest corner of Ohio (https://www.spc.noaa.gov/products/watch/). Given that the Storm Prediction Center has a potential area of severe weather further northeast for tomorrow (https://www.spc.noaa.gov/products/outlook/)... expecting the corridor of severe thunderstorms to shift northeast across Ohio... northwestern Pennsylvania... central New York State... and possibly into Vermont and New Hampshire in the next 24 hours. On a final note regarding ex-Beryl... models suggest an elevated amount of upper divergence on the east side of the supporting central North America upper trough such that the surface circulation of ex-Beryl remains low in pressure and vigorous for some time... as such all of the aforementioned land areas may see some gusty winds induced by ex-Beryl's surface low pressure field over the next day or so. This is my final statement on Beryl on this blog as it is no longer a tropical system.


AREA OF INTEREST #10... The surface tropical wave of low pressure that was previously over the Yucatan peninsula is now positioned over southeastern Mexico and the Bay of Campeche while continuing to be pushed west-northwest by surface ridging building in the wake of ex-Beryl. Upper winds over the tropical wave have become increasingly favorable for development while the suppressing inverted upper trough that was stacked over the wave has decayed into a weaker string of upper vorticity moving into east-central Mexico due to its prolonged isolation from high-latitude cold air. To the south of the decaying upper vorticity... thunderstorms associated with the wave flourished early this morning across the Isthmus of Teheuantepec and vicinity... then by the late morning the decaying thunderstorms over the Isthmus became replaced by curved bands of activity over the Bay of Campeche. Recently thunderstorms have flared up over central Veracruz and vicinity... with visible satellite animation and CIMSS 850 mb vorticity (https://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor&zoom=&time=) suggesting a better-defined spin developing on the northeast edge of the thunderstorms and just offshore of central Veracruz. It is likely the north side of the developing spin lacks thunderstorms due to the aforementioned decaying upper vorticity... however as the upper vorticity continues to fade upper-level winds over the developing spin will continue to favor it. Therefore I am assigning a low 10% chance of tropical cyclone formation for the next 12 hours and before the spin moves into northern Veracruz (low odds as the models are not showing tropical development and the NHC continues to not mention this system in their tropical weather outlook). Regardless of tropical cyclone formation or not... periods of heavy rainfall with flash flooding potential are possible across east-central Mexico (northern and central Veracruz... southern Tamaulipas... and vicinity) within the next 24 hours.

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

IOH 12 Hr Outlook (0600Z Jul 10)... 10% chance of tropical cyclone formation (just offshore of northern Veracruz near 21N-97W)

IOH 24 Hr Outlook (1800Z Jul 10)... 0% chance of tropical cyclone formation (inland over east-central Mexico near 22N-99W)

*****National Hurricane Center (hurricanes.gov) official outlook as of 2 PM EDT**************************

Not in the official outlook


...COMPUTER MODEL SUMMARY...

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


1200Z (Jul 9) CMC Model Run...

**For area of interest #10... no development shown

**Tail end of cold front attached to ex-Beryl develops into another frontal low over South Carolina at 60 hours due to split flow upper divergence between the flow ahead of the upper trough supporting ex-Beryl and northwesterly upper winds flowing into upper vorticity offshore of the southeastern US... through 84 hours the original surface center over South Carolina fades under suppressive upper convergence on the west side of the offshore upper vorticity while divergence on the northeast side of the offshore upper vorticity produces another possibly more tropical surface center just south of Cape Fear North Carolina... the potentially tropical surface center continues north-northeast across the North Carolina Outer Banks through 96 hours... the potentially tropical surface center then accelerates east-northeast across the northwest Atlantic while transitioning into an elognated remnant frontal low near 40N-63.5W by 138 hours... remnant frontal low located southeast of Newfoundland at 168 hours


0000Z (Jul 9) ECMWF Model Run...

**For area of interest #10... no development shown

**Tail end of cold front attached to ex-Beryl develops into another frontal low over the southern South Carolina coast at 60 hours supported by anticyclonic outflow between offshore upper vorticity to the southeast and upper trough supporting ex-Beryl to the northwest... regime of anticyclonic outflow continues over the frontal low as the offshore upper vorticity is swept north and away by the upper trough supporting ex-Beryl... however the frontal low does not undergo tropical development while degenerating into a remnant surface trough still positioned on the South Carolina coast through 102 hours... surface trough dissipates shortly thereafter


1200Z (Jul 9) GFS Model Run...

**For area of interest #10... no development shown

**Tail end of cold front attached to ex-Beryl develops into another frontal low over the South Carolina coast at 48 hours supported by anticyclonic outflow between offshore upper vorticity to the southeast and upper trough supporting ex-Beryl to the northwest... tropical development of the frontal low subsequently not forecast as it retrogrades west into and across the southeastern US under the influence of a north-central US surface ridge supported by the convergence on the back side of ex-Beryl's parent upper trough.


1200Z (Jul 9) NAVGEM Model Run...

**For area of interest #10... no development shown

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