MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #50

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

...FRIDAY AUGUST 1 2025 3:15 PM EDT...

As we kick off the month of August in the 2025 Atlantic Hurricane Season... development potential across the tropical latitudes of the Atlantic basin remains low due to ongoing dry Saharan air surges toward the east... and suppressing upper vorticity across the Caribbean and Gulf of America toward the west. Noting former central and western Atlantic upper troughs are merging into another wave of upper vorticity... which will slide southwest toward the Caribbean under the influence of the upper ridge now shifting offshore from the southeastern US.

For the mid-latitudes of the Atlantic basin... on the lookout for possible tropical development along the lengthy surface front now entering the northwestern Atlantic from North America in the days ahead. The front's supporting upper trough currently over eastern Canada leaves behind its tail over the Great Lakes and northeastern US whose southeastern divergence zone maintains the tail end of the surface front at a position offshore of the southeastern US and open northwestern Atlantic. In the longer range... the tail upper-level energy merges with surrounding upper troughs to make an eastern North America upper trough regime. There is agreement in the models that the upper trough regime undergoes a southwestern and northeastern split... offering a gap of low wind shear conducive to tropical development over offshore waters and in between the upper trough halves. Generally the GFS and CMC have been proponents of a tropical development signal along the surface front... and the ECMWF may be beginning to join as of 0000Z today albeit it is a weak signal with only a weak surface low/ inverted surface trough shown. The models that do suggest tropical development still have disagreement on when/ where it occurs... if further east and/ or sooner then the track would be northeast out to sea while entangled with the northeastern half of the upper trough split... if further west and/or later then the track would trend west toward the US east coast under the influence of a surface ridge that builds in the western convergence of the northeastern half of the upper trough split. Some runs even suggest the surface front decaying into multiple possibly tropical lows instead of just one. There is not enough consistency among models in this update cycle to begin a new area of interest with a track forecast and probability of tropical cyclone formation (and in the case of multiple surface lows would need more than one area of interest)... however on standby to add an area of interest in future updates should a model consensus develop and/ or based on satellite observations.

...COMPUTER MODEL SUMMARY...

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

1200Z (Jul 31) CMC Model Run...

**Current SW/NE tilted eastern Canada upper trough shifts southeast through 24 hours with which shifts the surface front produced by its southeastern divergence zone into northwestern Atlantic... the majority of the eastern Canada upper trough and a pair of elongated frontal lows it produces continue towards the open north Atlantic through 60 hours however the tail end of the front persists offshore of the southeastern US due to the southeastern divergence zone of a band of upper vorticity over the Great Lakes and NE US left behind by the upper trough... rapid tropical cyclone formation along the decaying tail end of the front and near 33.5N-71.5W through 72 hours... during tropical cyclogenesis and through 84 hours a pair of central US upper troughs and incoming upper trough from central Canada merge with Great Lakes/ NE US upper vorticity band to make a broad eastern North America upper trough and the tropical cyclone lifts northeast ahead of the upper trough and to 34.5N-70W where it proceeds to reach peak strength... the tropical cyclone transitions into a sheared and more elongated remnant low while continuing northeast to 37.5N-66W through 108 hours... the eastern North America upper trough splits into southwest and northeast halves with the remnant low becoming elongated further into a surface front positioned west-northwest of the Azores by 168 hours due to the elongated southeastern divergence zone of the northeast half of the upper trough split

0000Z (Aug 1) CMC Model Run...

**Similar results to CMC 1200Z Jul 31 run... with rapid tropical cyclone formation near 33.5N-73.8W at 54 hours... tropical cyclone reaching peak strength near 35N-70W at 72 hours... through 114 hours continues northeast while transitioning into a sheared and more elongated remnant low near 38.5N-59W... remnant low elongates further into a surface front through 168 hours while reaching waters west-northwest of the Azores

1200Z (Jul 31) ECWMF Model Run...

**No tropical development shown in the Atlantic basin through 7 days (168 hours)

0000Z (Aug 1) ECMWF Model Run...

**Similar result to 0000Z Aug 1 GFS model run detailed below where a portion of the tail end of surface front/ trough offshore of the southeastern US becomes a surface low with possible tropical development potential near 34N-70W by 138 hours... the weak surface low/ trough drifts west through 168 hours due to surface ridge to the north

0000Z (Aug 1) GFS Model Run...

**Current SW/NE tilted eastern Canada upper trough shifts southeast through 24 hours with which shifts the surface front produced by its southeastern divergence zone into northwestern Atlantic... the majority of the eastern Canada upper trough and a an elongated frontal low it produces continue towards the open north Atlantic through 60 hours however the tail end of the front persists offshore of the southeastern US due to the southeastern divergence zone of a band of upper vorticity over the Great Lakes and NE US left behind by the upper trough... through 84 hours a pair of central US upper troughs and incoming upper trough from central Canada merge with Great Lakes/ NE US upper vorticity band to make a broad eastern North America upper trough whose eastern divergence zone continues to maintain the tail end of the surface front/ trough offshore of the SE US... through 126 hours the eastern North America upper trough splits into southwest and northeast halves with a portion of the offshore surface front/ trough becoming a surface low with possible tropical development near 34.5N-71.5W due to a gap featuring low wind shear between the upper trough halves... the trailing convergence zone of the northeast half of the upper trough split produces a surface ridge to the north which in turn drives the possibly tropical low west toward the North Carolina Outer Banks through 168 hours

0600Z (Aug 1) GFS Model Run...

**No tropical development shown in the Atlantic basin through 7 days (168 hours)

1800Z (Jul 31) NAVGEM Model Run...

**No tropical development shown in the Atlantic basin through 7 days (168 hours)

0600Z (Aug 1) NAVGEM Model Run....

**No tropical development shown in the Atlantic basin through 7 days (168 hours)