MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #45

*******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 JULY 25 2025 11:00 PM EDT...

For the mid-latitudes of the Atlantic basin... the northwestern Gulf of America surface low is making landfall on the United States Gulf coast in the vicinity of the Texas/ Louisiana border and its tropical development potential has ended... see area of interest #11 section below for a final statement on this feature. Meanwhile... an additional surface low pressure area could descend southwestward into the northern Gulf in approximately 5 days from now to become yet another tropical area of interest in this region... more details as follows:

(1) Ahead of the surface front originally generated by the eastern divergence zone of the current eastern Canada upper trough... a pre-frontal surface trough of low pressure has developed over North Carolina and Virginia in the eastern divergence zone of a smaller shortwave upper trough in the region. Over the next 30 hours this surface low pressure feature is shown to fester over the Carolinas perhaps with the aid of upper anticyclonic outflow induced by the ongoing southeastern US upper ridge.

(2) Between 30 and 54 hours another shortwave upper trough and its associated surface front ejects east from the Great Lakes region into the northeastern US... with the tail end of that front potentially merging with the persistent Carolinas surface low pressure area as that front is pushed southeast by the surface ridge induced by the back convergent side of the shortwave upper trough. Noting what is the current north Atlantic upper trough has left behind a northwest Atlantic upper vortex and also a small piece of energy that has rapidly retrograded west across Florida and merged with the current Gulf of America inverted upper trough. The eastern convergence zone of the retrograding Gulf of America inverted upper trough will likewise cause a retrogression of the current surface ridge center offshore of the southeast US onto the US Gulf coast through 54 hours.

(3) From 54 to 120 hours the Carolinas surface low pressure area is coaxed southwest into the northern Gulf under the force of the US Gulf coast surface ridge... then a more sprawling and strong surface ridge descending from the US/Canada border induced by the back convergence zone of the next major upper trough to pass over Canada.

(4) This next northern Gulf surface low may then try to take advantage of outflow induced by the ongoing southeastern US upper ridge... however the upper vorticity currently near the northeastern Caribbean Islands is also scheduled to reach the Gulf as an inverted upper trough also around 120 hours. Tropical development potential will hinge on the exact positions of the surface low and the inverted upper trough... today the models have shifted toward a quicker arrival of the disruptive inverted upper trough which goes against tropical development potential. Moreover the models have some disagreement on the long-range position of the surface low in 5+ days... for example in the suite of recent model runs in the computer model summary section below the 12Z NAVGEM... CMC... and ECMWF had the surface low further north where there is increased land interaction with the southeastern US landmass during its lifecycle... only the 18Z GFS had the surface low further south over northern Gulf waters offshore of southeast Louisiana. Therefore not declaring a new tropical area of interest for this scenario during this update cycle.

For the tropical latitudes of the Atlantic basin:

(1) Tropical development in the waters between Africa and the Lesser Antilles continues to be suppressed by surges of dry Saharan air. Moreover upper winds in a swath of the eastern tropical Atlantic will be less favorable for development over the next 48 hours due to suppressing upper vorticity being pushed into the region by the current northeast Atlantic upper ridge cell (the unfavorable upper winds clear out after 48 hours once the upper vorticity is lifted north and away by the approach of the current east Canada upper trough... northwest Atlantic upper vortex... and upper vortex southwest of the Azores... however dry Saharan air will still continue to be a suppressing factor).

(2) Further west in the Caribbean Sea where dry Saharan air concentrations tend to be lower... upper winds have made a recovery (as far as supporting thunderstorms) where anticyclonic outflow has increased due to the weakening and westward departure of the upper vortex that was over Cuba 48 hours ago (the remains of that vortex is the current Gulf of America inverted upper trough). Thunderstorms across Central America and western Caribbean waters have been more robust compared to the past 24 hours due to the support of the expanding upper outflow... while surface analysis does not show a surface low pressure feature associated with the thunderstorms the CIMSS 850 mb vorticity product suggests increasing mid-level spin on the north coast of Honduras (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). If it persists... the mid-level disturbance through 48 hours would continue west-northwest into the Bay of Campeche under the same surface ridge steering area of interest #11. However some of the suppressing upper vorticity currently near the northeastern Caribbean Islands is expected to be pushed around the ongoing southeastern US upper ridge and overtop the Bay of Campeche around the same time... therefore tropical development is not anticipated in the short term in the western Caribbean nor the Bay of Campeche.

(3) For the longer range after day 4... the cool-core suppressing upper vorticity that descends southwest into the Caribbean Sea from the northeastern Caribbean islands is likely to weaken and break up from prolonged isolation from high-latitude cold air... this may give an opening for upper winds to become favorable for development in the Caribbean assuming that surface tropical waves of low pressure arriving from the east are not excessively weakened through their journey in higher concentrations of dry Saharan air. Noting for now models are not in agreement on long-range development in the Caribbean.

AREA OF INTEREST #11... As of 0600Z early today the National Hurricane Center (in the TAFB surface analysis) confirmed a southwestward reformation of the northern Gulf broad surface low into the northwestern Gulf near 27.5N-91W where warm core upper anticyclonic outflow perhaps enhanced by the latent heat release of last night's thunderstorms dropped surface pressures. Since then the broad surface low has turned north toward the Texas/ Louisiana border region while rounding the west side of the steering surface ridge (this is a multi-center ridge with one in the northwestern Atlantic supported by the back convergence zone of the current northwest Atlantic upper vortex... another offshore of the southeastern US supported by the eastern convergence zone of the inverted upper trough progressing across the Gulf of America... and a third one over the Great Lakes supported by the western convergence zone of the upper trough currently over eastern Canada). As of 0000Z (8 PM EDT) tonight the NHC in their tropical weather outlook had positioned the spin maximum of the broad surface low along the US Gulf coast at the Texas/ Louisiana border... while visible satellite animation of the low-level clouds as the sun was setting suggested the spin maximum was just offshore of the southeast corner of Texas in alignment with my previous track forecast... and the update forecast track in my outlook below is unchanged. Either way the spin maximum over the next 24 hours will be continuing north into land... ending tropical development potential. Noting the animation of low-level clouds on visible during the daylight suggests the broad surface low continues to be elongated southwest-to-northeast... and the CIMSS 850 mb vorticity product has been in agreement with this idea (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). This means the southwestern tail of the oblong surface low could be over northwestern Gulf water over the next several hours... however the risk of development of the southwestern tail should be curtailed by the incoming inverted upper trough to the east that will impart northeasterly shear on its west side and suppression of upper outflow directly below its axis... in fact scattered thunderstorms that were over the northwestern Gulf have since faded. This cool core inverted upper trough seems to be the cause of this system's failure to develop in the last 24 hours as last night's thunderstorms and associated latent heat release faded... hence failing to weaken the incoming inverted upper trough.

A recent round of thunderstorm cells brining heavy rainfall to Louisiana has since faded perhaps due to suppression brought on by the incoming inverted upper trough axis. Periods of heavy rainfall continue across eastern Texas... and as the remains of this system lift to the north in the next 24 hours periods of heavy rainfall cannot be ruled out for southeastern Oklahoma and Arkansas. Localized flash flooding cannot be ruled out from cells of heavy rainfall. This will be my final statement on this area of interest on this blog as it is no longer at risk for tropical development.

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

IOH 24 Hr Outlook (0000Z Jul 27)... 0% chance of tropical cyclone formation (eastern Texas near 32.5N-95W)

*****National Hurricane Center (hurricanes.gov) official outlook as of 8 PM EDT***********************

Formation chance through 48 hours... 0%

Formation chance through 7 days... 0%

...COMPUTER MODEL SUMMARY...

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

1200Z (Jul 25) CMC Model Run...

**For area of interest #11... current broad northwestern Gulf of America low turns northwest into the Texas/Louisiana border region through 6 hours... shortly thereafter continues north further inland and dissipates

1200Z (Jul 25) ECMWF Model Run...

**For area of interest #11... current broad northwestern Gulf of America low turns northwest into the Texas/Louisiana border region through 18 hours... shortly thereafter continues north further inland and dissipates

1800Z (Jul 25) GFS Model Run...

**For area of interest #11... current broad northwestern Gulf of America low is initialized on the coast at the Texas/Louisiana border region... within next few hours continues north further inland and dissipates

**Tropical wave emerges from the west coast of Africa at 69 hours... evolves into a tropical low near 12.5N-48.8W at 162 hours

1200Z (Jul 25) NAVGEM Model Run...

**For area of interest #11... current broad northwestern Gulf of America low turns northwest into the Texas/Louisiana border region through 12 hours... shortly thereafter continues north further inland and dissipates