MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #51A (Special Update)

*******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 3 2025 3:30 PM EDT...

The following is a special update on the frontal low that continues east-northeast between North Carolina and Bermuda... tagged as area of interest #13 in previous full update #51... as that feature has seen a notable increase in thunderstorms and its transition into a tropical cyclone appears to be underway. For information regarding activity elsewhere in the Atlantic tropics... refer to full update #51 (https://www.infohurricanes.com/post/my-2025-atlantic-hurricane-season-birdseye-view-post-51)

AREA OF INTEREST #13... Visible satellite image of frontal low positioned midway between North Carolina and Bermuda while gaining tropical characteristics... image taken 1716Z Sunday August 3:

A lengthy surface front remains positioned across the southeastern United States and northwestern Atlantic... one of the dominant features along the front is a surface low pressure spin that continues to produce thunderstorm activity while moving east-northeast into the waters midway between Bermuda and North Carolina. Because of the thunderstorm activity this feature continues to be monitored for transition into a tropical cyclone. After previously having a small central thunderstorm canopy around 0100Z early today... the canopy fizzled out and became replaced by curved thunderstorm bands east of the center. Since 1200Z an expanding central canopy of thunderstorms has re-developed... larger than the previous... and it appears transition from a frontal low into a tropical cyclone is underway and as such I have begun a tropical cyclone formation forecast with specific track and intensity projections. This system appears positioned just right for transitioning into a tropical cyclone where its poleward (northern) upper outflow is enhanced by the southwesterly jet ahead of the series of upper troughs to the northwest instead of being sheared by the jet... albeit there is also some shear affecting the central area as the thunderstorm canopy is lopsided to the east of center but not enough to prohibit tropical development.

The future track will depend on the interaction between the series of upper troughs to the northwest. In the short-term an upper trough that recently dived southeast into eastern Canada from central Canada will be merging with current upper troughs approaching from the central and eastern US to make an eastern North America upper trough. By the middle and end of the 5-day forecast period the eastern North America upper trough proceeds to split into three pieces per the latest model trends... one in the far northeast corner of the Atlantic... another an east-west ribbon of upper vorticity strung across the northwest Atlantic... and a weak upper trough stalled over the eastern US. The question is whether this system continues east-northeast out to sea while caught in the deep-layer weakness associated with the upper vorticity ribbon and remainder eastern part of the surface front to be maintained by the divergence ahead of the ribbon... or whether this system slows down its east-northeast progress or even stalls while becoming pinned by a surface ridge to the north that builds in the western convergence zone of the initial piece of energy that swings to the northeast Atlantic and is then maintained by convergence behind the upper vorticity ribbon. As of this morning the majority of the models still continuous east-northeast track out to sea while the GFS is still leaning toward the slow down/ stall idea. While my updated track forecast below remains a blend of the two extremes... it is leaning toward the GFS idea as this system's east-northeast progress is a little behind my previous forecast track. Due to the strength of the surface ridge... I show an east-southeast bend between 72 and 96 hours then east drift from 96 to 120 hours.

Regarding intensity... I forecast steady intensification into a high-end tropical storm through 48 hours as it continues to maintain its favorable position with respect to the southwesterly upper jet where the jet enhances its northern outflow. The updated slower forecast track keeps this system from outright walking into the jet where it would weaken and lose tropical cyclone status due to the high shear ripping away the core thunderstorms from the center... and where it would transition into a less tropical remnant low supported by the upper divergence. However this system won't be immune from shear either as there is still lighter shear south of the jet affecting the core of this system's circulation as noted in the above paragraphs... with the effect of the lighter shear becoming worse toward day 5 as the forecast track progresses toward a slower forward speed. I depict a tropical cyclone holding on to equilibrium strength as a lower-end tropical storm towards day 5 in the lighter shear.

If the forecast below holds... surf generated by this system could reach the shores of Bermuda tomorrow and Tuesday.

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

0 Hr Position (1800Z Aug 3)... Frontal low centered at 34N-72W

IOH 24 Hr Forecast (1800Z Aug 4)... 60 mph maximum sustained wind tropical storm centered northwest of Bermuda at 35N-67.5W

IOH 48 Hr Forecast (1800Z Aug 5)... 65 mph maximum sustained wind tropical storm centered north-northeast of Bermuda at 36N-63.5W

IOH 72 Hr Forecast (1800Z Aug 6)... 50 mph maximum sustained wind tropical storm centered in the northwestern Atlantic at 36.5N-61.5W

IOH 96 Hr Forecast (1800Z Aug 7)... 45 mph maximum sustained wind tropical storm centered in the northwestern Atlantic at 36N-60.5W

IOH 120 Hr Forecast (1800Z Aug 8)... 45 mph maximum sustained wind tropical storm centered in the northwestern Atlantic at 36N-59W

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

Formation chance through 48 hours... 70%

Formation chance through 7 days... 70%