MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #56

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

...SUNDAY AUGUST 10 2025 7:30 PM EDT...

Atlantic tropical activity has increased further as we move to mid-August with the number of concurrent areas of interest increasing to four:

(1) See area of interest #14 section below for an update on the open central Atlantic tropical low still being monitored for signs of development

(2) See area of interest #15 section below for an update on the northwestern Atlantic frontal low which may still acquire tropical characteristics as wind shear later drops.

(3) See area of interest #16 section below for an update on the large eastern Atlantic tropical wave of low pressure which may develop into a tropical cyclone over the northern Republic of Cabo Verde Islands tonight. If short-term tropical cyclone formation does not occur... the tropical wave is likely to later develop in the open central Atlantic while reaching warmer waters and reduced concentrations of dry Saharan air.

(4) See area of interest #17 section below for information on a new disturbance in the eastern Gulf of America which may develop within the next 48 hours while moving northwest toward the western Florida panhandle... southern Alabama... and southeastern Mississippi.

Elsewhere in the Atlantic basin... yet another tropical disturbance may emerge in the eastern tropical Atlantic within the 2 to 5 day window within the next large tropical waves of low pressure to emerge from western Africa.

AREA OF INTEREST #14... The small tropical low pressure in the open central Atlantic was positioned near 24N-51W as of 1800Z today. Its original thunderstorm canopy that it displayed for the latter half of Friday had fizzled on Saturday while the tropical low ingested dry Saharan air... however as of today the tropical low persists with a comma-shaped thunderstorm mass. The dry air episode likely prevented the tropical low from maintaining enough strength to have a closed surface circulation... and as of this afternoon it is hard to spot a closed spin in the low clouds at the head of the comma-shaped cloud canopy in visible satellite animation. Currently at a critical juncture where this system could reform to the north while becoming a system supported by the eastern divergence zone of the nearby mid-ocean upper vortex... or this system continues west-northwest under the influence of the surface ridge currently entering the western Atlantic from the coastal northeastern US. Noting the CMC... ECMWF... and projected track in the NHC tropical weather outlook show the immediate reformation to the north... while the GFS shows a continued west-northwest track as an inverted surface trough. Even though this system does not have a fully closed spin in visible satellite... the CIMSS 850 mb vorticity product shows a spin that is still sufficiently strong which makes it harder for a reformation to the north (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=) and thus continuing with a west-northwest track in my updated outlook below. In that scenario conditions for development are favorable due to an upper ridge cell (low shear/ upper outflow potential) to the southwest of the mid-ocean upper vortex. I have dropped my peak odds of tropical cyclone formation to 50% as this system does not currently have a fully closed spin... and have shorter-term odds below the peak to give time for this system to establish one.

By days 4 and 5 the outlook below shows a north turn into the waters southeast of Bermuda as the western Atlantic surface ridge begins to fade due to the approach of a large-scale frontal system from eastern Canada and northeastern US. The warm sector upper ridge associated with the frontal system forces the upper vortex over area of interest #15 to become an elongated north-south upper trough... with the south base of the upper trough digging toward this area of interest. As a result this area of interest could already be tracking straight north on day 4 despite the western Atlantic surface ridge not yet fully dissipating... while transitioning into a feature supported by the eastern divergence zone of the upper trough. The latest model data shows the majority of the nearby upper trough becoming scooped into the larger scale upper trough approaching from eastern Canada around day 4... with the tail end what is left of the upper trough dissipating by day 5. This keeps westerly shear levels low through day 5... and I maintain 50% odds of tropical cyclone formation through that time.

If this system tracks further west as shown in the outlook below... and gains tropical cyclone strength... it could generate surf that reaches the shores of Bermuda in the Wednesday through Friday timeframe.

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

IOH 24 Hr Outlook (1800Z Aug 11)... 30% chance of tropical cyclone formation (central Atlantic near 25.5N-54.5W)

IOH 48 Hr Outlook (1800Z Aug 12)... 40% chance of tropical cyclone formation (central Atlantic near 26N-59W)

IOH 72 Hr Outlook (1800Z Aug 13)... 50% chance of tropical cyclone formation (southeast of Bermuda near 27.5N-62W)

IOH 96 Hr Outlook (1800Z Aug 14)... 50% chance of tropical cyclone formation (southeast of Bermuda near 30N-62.5W)

IOH 120 Hr Outlook (1800Z Aug 15)... 50% chance of tropical cyclone formation (east of Bermuda near 32N-60.5W)

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

Formation chance through 48 hours... 10%

Formation chance through 7 days... 20%

AREA OF INTEREST #15... The frontal low pressure that was east of North Carolina on Friday has continued east-northeast into the open northwest Atlantic over the weekend and was positioned at 38N-62W as of 1800Z today. The shower and thunderstorm tops are removed well to the northeast of the surface swirl as westerly shear is elevated due to the current southwest-northeast tilt configuration of the frontal low's supporting upper trough. The upper trough is currently amplifying into a cut-off upper vortex due to an amplifying upstream warm core upper ridge induced by the warm southwesterly flow ahead of a large-scale frontal system developing over Canada... once the frontal low whirls beneath the upper vortex wind shear will be lower. Combined with the system still being over 26 deg C waters... I continue to hang on to this area of interest as a tropical area of interest and this past 1200Z GFS model run still suggests possible acquisition of tropical characteristics. I continue to hold a low 20% chance that this system acquires tropical characteristics as the GFS is an exception rather than the consensus among the family of global models. Note the model consensus has switched back to having the frontal low whirling beneath the core of the upper vortex which keeps it trapped further south for longer... and my updated forecast track below is adjusted accordingly. Thus if this system were to gain tropical characteristics it would more likely be subtropical instead of tropical... and the designations in my updated outlook below are switched to subtropical. Finally by Wednesday the upper vortex and surface low move north in tandem and over cooler waters while pulled by the upper trough and surface frontal system approaching from Canada. The upper vortex is not particularly cold enough to support instability and thunderstorms at waters below 26 deg C... and I drop odds of subtropical cyclone formation to 0% by 72 hours.

Noting if this system were to gain enough strength as a subtropical system... it could generate surf reaching the shores of Nova Scotia by Wednesday.

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

IOH 24 Hr Outlook (1800Z Aug 11)... 20% chance of subtropical cyclone formation (northwest Atlantic near 39.5N-61.5W)

IOH 48 Hr Outlook (1800Z Aug 12)... 20% chance of subtropical cyclone formation (northwest Atlantic near 39.5N-61.5W)

IOH 72 Hr Outlook (1800Z Aug 13)... 0% chance of subtropical cyclone formation (south-southeast of Nova Scotia near 40.8N-61.5W)

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

Not in the official outlook

AREA OF INTEREST #16... Infrared satellite image of organizing tropical low moving into the northern Republic of Cabo Verde Islands as of 2320Z:

Recent developments associated with the large tropical wave of low pressure in the eastern tropical Atlantic were covered in special update #55A (https://www.infohurricanes.com/post/my-2025-atlantic-hurricane-season-birdseye-view-post-55a-special-update)... much of the text from that update is re-used here:

The large size of the tropical wave that emerged from western Africa late Friday and early Saturday was re-enforced while absorbing a previously inactive wave southwest of the Republic of Cabo Verde Islands. A smaller low pressure spin with increasingly organized thunderstorms has developed within the east side of the large wave... and has moved northwest into the northeastern islands due to the cyclonic flow of the rest of the large wave. The organization has improved further this afternoon as the pattern of thunderstorm bands has become replaced by a stronger circular central thunderstorm burst... and I project a high 70% chance of tropical cyclone formation in the next 12 hours. Tropical cyclone like conditions such as gusty winds and heavy rains are likely occurring beneath the burst and over the northeastern islands... and overnight should transfer to the northwestern islands as the track of the tropical low turns west while it bumps into the Atlantic surface ridge. The thunderstorm burst was likely initiated by the tropical low pulling in moist air from the southeast... however between 12 and 24 hours I drop odds of tropical cyclone formation to 40% as this system track into marginal sea surface temperatures and potentially wraps in the dry Saharan air to the west which would wrap around the central thunderstorm canopy and potentially weaken it. The tropical low then continues briskly west-northwest across the Atlantic tropics due to its initial more north position closer to the surface ridge... reaching warmer sea surface temps and lower concentrations of dry Saharan air with time and it makes sense to have high odds of tropical cyclone formation again by day 5. By day 4 I bend the track slightly more north with a slowing forward speed as this system has a high chance of being strong/ tall enough by then to be dragged by upper southwesterly flow streaming into the current mid-ocean upper vortex. The same slowed forward speed and slightly higher north angle is continued into day 5 due to the developing western Atlantic ridge weakness associated with an upper trough and surface frontal system emerging from eastern Canada and the northeastern US. The long range track beyond day 5 will depend on the exact evolution of the upper trough and surface frontal system... and due to the usual long range model errors those exact details cannot be known at this time.

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

IOH 12 Hr Outlook (0600Z Aug 11)... 70% chance of tropical cyclone formation (just northwest of the Republic of Cabo Verde Islands near 17.5N-25.5W)

IOH 24 Hr Outlook (1800Z Aug 11)... 40% chance of tropical cyclone formation (eastern tropical Atlantic near 17.8N-28.5W)

IOH 48 Hr Outlook (1800Z Aug 12)... 50% chance of tropical cyclone formation (eastern tropical Atlantic near 18N-35.5W)

IOH 72 Hr Outlook (1800Z Aug 13)... 60% chance of tropical cyclone formation (central tropical Atlantic near 18.5N-42W)

IOH 96 Hr Outlook (1800Z Aug 14)... 80% chance of tropical cyclone formation (central tropical Atlantic near 19.5N-49W)

IOH 120 Hr Outlook (1800Z Aug 15)... 80% chance of tropical cyclone formation (central tropical Atlantic near 20.5N-54W)

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

Formation chance through 48 hours... 50%

Formation chance through 7 days... 90%

AREA OF INTEREST #17... The surface trough of low pressure that was attached to the southwest side of the western Atlantic frontal low (area of interest #15) has detached and begun moving west while pushed by the surface ridge currently over the coastal northeastern US... and as of 1800Z the trough axis was nearing the southeastern US coast and continues to straddle the Florida peninsula. A persisting thunderstorm complex at the southwest end of the surface trough... supported by the outflow of the upper ridge cell in the region... is positioned in the eastern Gulf of America and just offshore of the southwestern Florida peninsula. The thunderstorms have shown increasing banding features and the CIMSS 850 mb vorticity product is showing increasing spin at this location (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). Have upgraded the area of thunderstorms to an area of interest for possible tropical development... the seventeenth tracked on this site this year. The upper vorticity over the eastern US is retrograding northwest and away while attracted toward the current central Canada upper trough which will keep the favorable upper ridge cell (low shear/ upper outflow) on top of the tropical disturbance. I have already started with 30% odds of tropical cyclone formation due to the above-mentioned organization showing in satellite data... waiting to see if computer models come on board and/or if organization on satellite persists before issuing higher odds. While rounding the west side of the aforementioned surface ridge this system will track northwest toward the western Florida panhandle... southern Alabama... and southeastern Mississippi through Tuesday. Interests here should be aware of this disturbance for possible Tuesday impacts including potential heavy rainfall with flash flooding... with gusty winds and surf toward the coast should tropical cyclone formation occur.

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

IOH 24 Hr Outlook (1800Z Aug 11)... 30% chance of tropical cyclone formation (northeastern Gulf of America near 27.5N-85.5W)

IOH 48 Hr Outlook (1800Z Aug 12)... 30% chance of tropical cyclone formation (just offshore of the Alabama/ Florida border near 30N-87W)

IOH 72 Hr Outlook (1800Z Aug 13)... 0% chance of tropical cyclone formation (northern Alabama near 33.5N-86.5W)

*****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/).

0000Z (Aug 10) CMC Model Run...

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

**For area of interest #15... Surface low strengthens over next 18 hours while reaching 39N-60.5W... the supporting upper trough to the northwest becomes a cut-off upper vortex with the surface low becoming quasi-stationary near 40N-60W through 72 hours while trapped under the vortex... subsequently turns north-northeast into Newfoundland through 108 hours where it loses identity to low pressure field of approaching eastern Canada frontal system

**For area of interest #16... Small tropical low within southeast side of large tropical wave moves northwest while orbiting the remainder of the wave and reaches the northeastern Republic of Cabo Verde Islands by 24 hours... tropical cyclone formation suggested just northwest of the Republic of Cabo Verde Islands at 36 hours... proceeds west while weakening back to a remnant low positioned near 19N-31.5W by 48 hours... regains tropical cyclone status near 19N-54W at 126 hours... gains hurricane strength near 20N-59W at 144 hours... positioned north of the Virgin Islands and Puerto Rico as a potentially intense hurricane by 168 hours

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

0000Z (Aug 10) ECMWF Model Run...

**Checked this ECMWF model run at tropical tidbits as the above-mentioned source had data from several forecast timestamps missing (https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=atl&pkg=mslp_pcpn&runtime=2025081000&fh=18)

**For area of interest #14... turns north in the flow between the Atlantic surface ridge and area of interest #15 and becomes a surface low near 34.5N-50.5W at 66 hours... surface low turns northeast in the flow ahead of frontal system approaching from eastern Canada and reaches 43N-37W at 168 hours

**For area of interest #15... Surface low strengthens over next 36 hours while reaching 38.5N-58.5W... the supporting upper trough to the northwest becomes a cut-off upper vortex and the surface low whirls northwest into the core of the upper vortex through 72 hours and near 41.5N-59W while weakening... drifts north toward eastern tip of Nova Scotia through 96 hours where it loses identity to low pressure field of approaching eastern Canada frontal system

**For area of interest #16... Small tropical low within southeast side of large tropical wave moves northwest while orbiting the remainder of the wave and reaches the Republic of Cabo Verde Islands by 24 hours where it proceeds to lose identity within the large wave... a new tropical low develops at north apex of the wave and near 18.5N-37.5W at 66 hours... tropical cyclone formation suggested near 23N-61W at 144 hours... tropical cyclone positioned near 24.5N-65W at 168 hours

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

**Large tropical wave emerges from west coast of Africa at 63 hours... becomes a large tropical low whose centroid is just west of the Republic of Cabo Verde Islands at 111 hours... the large tropical low reaches 41W longitude while taking on an elongated north-south structure

1200Z (Aug 10) GFS Model Run...

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

**For area of interest #15... surface low generally quasi-stationary at current location through 54 hours while becoming trapped beneath supporting upper trough to the northwest as that trough amplifies into an overhead cut-off upper vortex... potentially gains tropical characteristics through 63 hours while drifting northeast to 40N-60W... the surface low then accelerates north-northeast into Newfoundland through 99 hours where it loses identity to low pressure field of approaching eastern Canada frontal system

**For area of interest #16... Small tropical low within east side of large tropical wave moves northwest while orbiting the remainder of the wave and reaches the northeastern Republic of Cabo Verde Islands by 15 hours... the tropical low then turns west with tropical cyclone formation suggested near 18N-31.5W at 39 hours... the tropical cyclone proceeds west-northwest with an eventual north turn while gaining hurricane strength and reaches 23N-59W at 168 hours as a potentially intense hurricane

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

**Large tropical wave emerges from west coast of Africa at 54 hours and proceeds to develop into a tropical low near 11.5N-20.5W... the tropical low proceeds to drift northwest toward the southeastern Republic of Cabo Verde Islands through 114 hours as it becomes a larger feature while merging with another tropical wave emerging from the west coast of Africa... the enlarged tropical low then turns west away from the islands and reaches 16N-32.5W at 168 hours

1200Z (Aug 10) NAVGEM Model Run...

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

**For area of interest #15... surface low generally quasi-stationary at current location through 54 hours while becoming trapped beneath supporting upper trough to the northwest as that trough amplifies into an overhead cut-off upper vortex... the surface low then accelerates north-northeast into Newfoundland through 114 hours where it loses identity to low pressure field of approaching eastern Canada frontal system

**For area of interest #16... Small tropical low within east side of large tropical wave moves northwest while orbiting the remainder of the wave and reaches the Republic of Cabo Verde Islands by 12 hours... proceeds to turn west with tropical cyclone formation suggested near 18N-37W at 54 hours... while becoming a large and intense hurricane reaches 23.5N-61W at 168 hours

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

**Large tropical wave emerges from west coast of Africa at 54 hours and organizes into a large tropical low whose centroid is just south of the Republic of Cabo Verde Islands by 90 hours... centroid of large tropical low reaches 13N-38.8W at 168 hours