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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 2023 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #41

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


...FRIDAY JULY 28 2023 2:45 PM EDT...

Atlantic tropical activity remains active with multiple areas of interest in progress:

(1) See area of interest #14 section below for an update on the tropical wave that is now moving across the central Caribbean and into Nicragua and Honduras

(2) See area of interest #17 section below for more information on a tropical wave of low pressure moving into the central tropical Atlantic being monitored for signs of development by the NHC for the days ahead... this wave is forecast to pass just northeast of the Lesser Antilles in about three days

(3) See area of interest #18 sections below for an update on the disturbance that was over the northwestern Bahamas... which over the last several hours relocated northward and is making landfall over the Florida/Georgia border region.


Elsewhere... satellite imagery shows another tropical wave of low pressure from western Africa is now entering the eastern tropical Atlantic with vigorous thunderstorm activity. As the current central Atlantic upper vorticity to the north gradually fades from ongoing isolation from high-latitude cold air... it will gradually dissipate which will allow for the tropical Atlantic upper ridge axis to shift north. This may later subject this tropical wave to less favorable easterly shear on the south side of the upper ridge axis instead of allowing the tropical wave to develop in the low shear/outflow environment closer to the upper ridge axis... therefore this tropical wave is not an area of interest for further development at this time.


AREA OF INTEREST #14... The tropical wave of low pressure over the central Caribbean Sea overnight has redeveloped concentrated thunderstorms along the southern part of its axis while continuing westward. In the upper-levels... this tropical wave is finding itself underneath an upper anticyclone that has developed in between central Atlantic upper vorticity to the northeast and northwest Caribbean upper vorticity to the northwest. The low shear and upper outflow of the anticyclone has aided in the tropical wave's overnight re-development. The updated forecast track of this disturbance in the outlook below is now adjusted notably southward where the thunderstorm activity is occurring... which will now take it over Nicaragua and Honduras where it will be capaable of producing heavy rainfall with flash flooding potential over the next 24 hours. Belize may also see heavy rainfall from this tropical wave. Because of this land interaction tropical cyclone formation for this disturbance no longer appears possible... and this will be my planned final statement on this tropical wave on this blog unless it continues to be mentioned in the National Hurricane Center tropical weather outlook by my next update... or unless the northern part of the wave axis later produces notable thunderstorm activity over offshore northwestern Caribbean or southwestern Gulf of Mexico waters.

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

IOH 24 Hr Outlook (1200Z Jul 29)... 0% chance of tropical cyclone formation (northwestern Nicaragua near 13N-85.5W)

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

Formation chance through 48 hours...10%

Formation chance through 7 days (168 hours)...10%


AREA OF INTEREST #17... A tropical wave of low pressure is now entering the central tropical Atlantic from the eastern Atlatnic while having continued westward. Over the last day or so the thunderstorm activity of the tropical wave has increased in a west-southwest (WSW) to east-northeast (ENE) elongated envelope... and as of 1200Z the NHC TAFB analyzed that the wave axis was in the middle of this envelope along 40W longitude. The CIMSS 850 mb vorticity product (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=) also confirms the WSW-ENE elongated tropical wave structure. It is now clear the models have insisted on a more northward track of this disturbance while having the developing ENE end of the structure... which was near 13.5N-37.5W at 1200Z... perform a fujiwhara interaction with the WSW end of the structure... and my updated forecast track of this disturbance is adjusted northward accordingly. The current upper troughing over eastern North America will soon move offshore into the Atlantic where it will induce a surface ridge weakness... and a northward turn into the weakness is anticipated in the longer range. Regarding odds of development... I have raised peak odds to 40% due to persisting computer model support and the increase in thunderstorm activity noted above. I have not yet gone above 50% for the peak odds as the forecast track of this disturbance takes it across the dry Saharan air swath in the short-term... and then toward the south side of the central Atlantic upper vorticity from 48 to 96 hours which will likely result in westerly shear. By 120 hours the cool core upper vorticity is forecast to dissipate due to prolonged isolation from high-latitude cold air... making conditions most favorable for development within the 5-day forecast window.


Note the updated forecast track has this disturbance now clearing the Lesser Antilles to the northeast. However should this disturbance develop early... it may become strong enough to produce coastal surf that reaches the northern islands.

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

IOH 24 Hr Outlook (1200Z Jul 29)... 10% chance of tropical cyclone formation (central tropical Atlantic near 15.5N-44W)

IOH 48 Hr Outlook (1200Z Jul 30)... 30% chance of tropical cyclone formation (central tropical Atlantic near 18N-52W)

IOH 72 Hr Outlook (1200Z Jul 31)... 30% chance of tropical cyclone formation (central Atlantic near 22.5N-57.5W)

IOH 96 Hr Outlook (1200Z Aug 1)... 30% chance of tropical cyclone formation (central Atlantic near 26N-57.5W)

IOH 120 Hr Outlook (1200Z Aug 2)... 40% chance of tropical cyclone formation (central Atlantic near 32N-56W)

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

Formation chance through 48 hours...20%

Formation chance through 7 days (168 hours)...60%


AREA OF INTEREST #18... The surface trough that was over the northwestern Bahamas yesterday has undergone some changes over the last day that have notably changed its outcome. Although the disturbance became better organized... it did so towards the north side of the trough axis and just offshore of the Florida/Georgia border. More recently the organizing center of circulation made landfall on the Florida/Georgia border which has brought an end to tropical cyclone formation potential for this disturbance... and what is left of the disturbance's surface low pressure center will drift north-northwestward further into Georgia while rounding the west side of the steering Atlantic surface ridge. It is probable that the disturbance relocated further north due to the suppressive upper vorticity in the Gulf of Mexico toward the southwest and more favorable upper anticyclonic cell of upper outflow located toward the northeast. This is my planned final statement on this disturbance on this blog unless it continues to be mentioned in the NHC tropical weather outlook by my next update. Due to the northward relocation of this disturbance... the potential for locally heavy rainfall over the next several hours has likewise shifted northward into Georgia and South Carolina. The Florida peninsula is also likely to see locally heavy rainfall based on the latest satellite and doppler radar presentation.

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

IOH 24 Hr Outlook (1200Z Jul 29)... 0% chance of tropical cyclone formation (east-central Georgia near 31.5N-81.8W)

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

Formation chance through 48 hours...0%

Formation chance through 7 days (168 hours)...0%


...COMPUTER MODEL SUMMARY...

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


0000Z (Jul 28) CMC Model Run...

**For area of interest #14... no development shown

** For area of interest #17... while curving northwest develops into a tropical low near 22N-56W at 84 hours... curves north to 27N-58W through 108 hours where it develops into a tropical depression... becomes a briskly strengthening compact tropical storm at 30N-58W at 120 hours.

**For area of interest #18... no development shown


0000Z (Jul 28) ECMWF Model Run...

**For area of interest #14... no development shown

** For area of interest #17... while curving northwest develops into a tropical low near 24N-54W at 78 hours... develops into a tropical cyclone near 30N-55W at 114 hours which begins to briskly strengthen as a compact tropical storm through 120 hours

**For area of interest #18... no development shown


0600Z (Jul 28) GFS Model Run...

**For area of interest #14... no development shown

**For area of interest #17... develops into a tropical low near 17N-44W at 33 hours... tropical cyclone formation suggested near 24N-55W at 78 hours... accelerates north to 33N-55W through 120 hours while strengthening into a hurricane.

**For area of interest #18... no development shown


0600Z (Jul 28) NAVGEM Model Run...

**For area of interest #14... no development shown

** For area of interest #17... no development shown

**For area of interest #18... no development shown

**Large tropical low emerges from western Africa at 138 hours... moves into the Republic of Cabo Verde Islands at 168 hours.

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