MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #22

*******Note that forecasts 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...SUNDAY JUNE 22 2025 8:15 PM EDT...

As of 8 PM EDT... the National Hurricane Center has increased odds of tropical cyclone formation to 40% for the open central Atlantic tropical low pressure spin... the feature tagged as area of interest #6 in this blog post. On colorized infrared satellite a very small area of thunderstorms is present but just east of the surface center rather than over it... a sign that westerly shear may already be developing in the environment of this system. Therefore I have not increased my odds of tropical cyclone formation above 20% as of this writing.

...SUNDAY JUNE 22 2025 7:50 PM EDT...

See area of interest #6 section below for information on the new area of interest in the open central Atlantic being monitored for possible tropical development... positioned near 31N-57.5W as of this writing.

For the western Atlantic tropical latitudes (western Caribbean and Bay of Campeche) and eastern Pacific... the current string of upper vorticity along 25N latitude has already begun to weaken while isolated from high-latitude cold air due to the current eastern US heat wave upper ridge. This is allowing for increased upper anticyclonic outflow over the south-central Caribbean... southern Central America... and far eastern Pacific resulting in increased widespread shower and thunderstorm activity in the region. Initially was anticipating the shorter-term formation of a well-defined Central America upper anticyclone to develop between Gulf of America and western Atlantic cells of fading upper vorticity... especially as the current United States upper ridge cell forces the Gulf of America vorticity to retrograde west toward Mexico thus creating an increasing gap for presence of an upper anticyclone in between the two cells of upper vorticity. However today's model runs suggest the two cells of upper vorticity may stay connected in the short-term as both retrograde westward in tandem... thus we may have to wait as late as 5+ days before the Central America upper anticyclone reaches full maturity when both linked cells of upper vorticity collapse further. In the days ahead will be watching for possible eastern Pacific and/or western Caribbean/Bay of Campeche tropical development as the outflow of the upper anticyclone promotes regional thunderstorms and lower surface pressures. The NHC is currently monitoring for the next eastern Pacific development in their tropical weather outlook which will likely spring up from the newly-formed tropical low near 7.5N-90W... for more on the possible eastern Pacific development see outlook at hurricanes.gov as this site is focused on Atlantic basin tropical development. Meanwhile not declaring an area of interest for the Atlantic basin side (western Caribbean/ Bay of Campeche) until the global models are in better agreement on development in that area and/or future satellite observations during future updates warrant.

AREA OF INTEREST #6... See the introduction section of previous post #21 for the origins of the open central Atlantic surface trough of low pressure that was in the vicinity of 30N-60W (https://www.infohurricanes.com/post/my-2025-atlantic-hurricane-season-birdseye-view-post-21). Over the last 12 hours a well-defined and fully closed surface low pressure spin has developed along the trough and near 31N-57.5W as seen in satellite animation... ASCAT-C descending pass (https://manati.star.nesdis.noaa.gov/datasets/ASCATCData.php)... and the CIMSS 850 mb vorticity product (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). The National Hurricane Center has added this feature as an area of interest for possible tropical development as this system has developed spiral bands of showers and thunderstorms... and this is the sixth tropical Atlantic area of interest tracked on this site this year. The surface low has begun to move northeast in the flow ahead of the nearby cold front delivered by the frontal low that recently departed Atlantic Canada... and will continue increasingly faster to the northeast in the flow ahead of the current Maine/Canada frontal low followed by the current north-central US frontal low once that system also reaches Atlantic Canada and offshore north Atlantic waters. On the current forecast track this system moves into less favorable water temps below 26 deg C after 24 hours... however was initially considering issuing higher than the NHC's current 20% odds of tropical cyclone formation for the next 24 hours due to the healthy initial structure of this system. A look at today's most recent model runs however suggest that some of the upper vorticity associated with the current passing northwest Atlantic upper trough could become cut-off along the forecast path of this system... different than yesterday where the models suggested that all of the upper vorticity retrogrades west and away under the influence of the east-shifting United States upper ridge. Therefore in as soon as 24 hours this system could be exposed to increased westerly shear induced by the south side of the upper vorticity left in this system's path... and I have to agree with the NHC's low 20% odds of tropical cyclone formation. Then by 48 hours this system is over cooler waters and moves directly underneath the suppressing upper vorticity... thus I drop odds of development to 0% for that timeframe and end my outlook at that point.

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

IOH 24 Hr Outlook (1800Z Jun 23)... 20% chance of tropical cyclone formation (central Atlantic near 34N-56W)

IOH 48 Hr Outlook (1800Z Jun 24)... 0% chance of tropical cyclone formation (central Atlantic near 36N-51W)

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

Formation chance through 48 hours... 20%

Formation chance through 7 days... 20%

...COMPUTER MODEL SUMMARY...

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

1200Z (Jun 22) CMC Model Run...

**For area of interest #6... no development shown as the weak surface low moves northeast through 72 hours while losing identity to current north-central US frontal low as that frontal low later enters the north Atlantic from Atlantic Canada

**By 84 hours a broad tropical low becomes established in the eastern Pacific offshore of the western Central America coast... by 156 hours a smaller eastern Pacific tropical cyclone develops within the broad low at a location offshore of south-central Oaxaca... as the small tropical cyclone nears the shore of Oaxaca another better-defined center develops in the central Bay of Campeche by 162 hours

0000Z (Jun 22) ECMWF Model Run...

**For area of interest #6... through 42 hours the weak surface low gains a little strength while reaching 34N-53.8W... afterwards continues northeast and by 78 hours loses identity to current north-central US frontal low as that frontal low later enters the north Atlantic from Atlantic Canada

1200Z (Jun 22) GFS Model Run...

**For area of interest #6... no development shown as the weak surface low moves northeast through 75 hours while losing identity to current north-central US frontal low as that frontal low later enters the north Atlantic from Atlantic Canada

**Through 72 hours eastern Pacific tropical cyclone formation shown to occur near 8N-92W with an eastern Pacific broad tropical low materializing north of the tropical cyclone and another broad tropical low materializing over the south-central Caribbean... through 120 hours the eastern Pacific tropical cyclone weakens while merging with the broad tropical low with the south-central Caribbean tropical low cyclonically orbiting the merged eastern Pacific circulation and sliding northwest onto the north-facing Honduras coast by 120 hours... through 168 hours the Honduras circulation merges with the eastern Pacific circulation with the merged system continuing west-northwest and covers the Bay of Campeche to the Gulf of Tehuantepec (within the south end of the merged circulation another eastern Pacific tropical cyclone materializes near the Gulf of Tehuantepec)

1200Z (Jun 22) NAVGEM Model Run...

**For area of interest #6... through 36 hours the weak surface low gains a little strength while reaching 33N-55W... afterwards continues northeast and by 78 hours opens to a surface trough near 36.5N-50W due to passing low pressure field of frontal low that ejects from Atlantic Canada and across the north Atlantic... through 168 hours the remnant trough transitions into a remnant frontal low reaching the northern British Isles

**Over next 48 hours a tropical cyclone develops over the eastern Pacific to the west of Costa Rica... after 48 hours the tropical cyclone proceeds northwest parallel to the western Central America coast while surface pressures stay low to the east of the cyclone and over Central America... by 108 hours the eastern Pacific tropical cyclone moves into the Gulf of Tehuantepec then gets pulled east for a landfall on the east coast of the Gulf by 132 by the Central America broad low as the Central America broad low moves west-northwest into western Central America... after absorbing the landfalling eastern Pacific tropical cyclone the western Central America broad low drifts west-northwest into southeastern Mexico and the Bay of Campeche through 168 hours