MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #36

*******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 JULY 13 2025 4:15 PM EDT...

URGENT - See area of interest #9 section below for an area of increasing thunderstorms and rotation that has developed today offshore of the southeastern United States at the tail end of a low-level trough of low pressure. Will monitor this feature for signs of short-term tropical development before it moves west-southwest into northern Florida over the next 36 hours... and will provide special updates on this feature before my next full update on the Atlantic tropics if odds of short-term tropical cyclone formation increase.

For the tropical latitudes of the Atlantic basin... tropical development continues to be precluded by surges of dry Saharan air. Furthermore upper-level winds are unfavorable for tropical development across the Caribbean and Bay of Campeche due to a upper westerly shearing winds on the south side of a band of upper vorticity in the region.

AREA OF INTEREST #9... Satellite sequence of increasing thunderstorms and mid-level low pressure spin developing offshore of the southeastern United States today:

Through 0000Z early today... the surface trough of low pressure that was over the mid-Atlantic United States has been dragged east-southeast into eastern North Carolina by the northwest Atlantic frontal low that has been moving east just offshore of Atlantic Canada and its trailing surface cold front. On 2 PM EDT Saturday the National Hurricane Center declared an area of interest for possible tropical development in the northeastern Gulf of America as the surface trough retrogrades southwest toward the Gulf while upper winds potentially become conducive... this will mark the ninth Atlantic tropical area of interest tracked on this site this year. In the above charts dated 0000Z... I initially positioned the new area of interest over eastern North Carolina where the surface trough was positioned in the NHC TAFB surface maps. From 0700Z to 1500Z... a billowing area of thunderstorms developed offshore of the southeastern United States and the CIMSS 850 mb vorticity product is confirming an increasing mid-level rotation in the activity (https://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). Water vapor satellite imagery shows the upper trough tied to the northwest Atlantic frontal low is leaving behind a small upper vortex just south of Cape Hatteras North Carolina... and split flow upper divergence between the southwest side of the upper vortex and east side of an upper anticyclonic ridge over the southeastern United States is supporting the thunderstorm activity and dropping pressures in the middle and lower layers of the atmosphere. As such the surface trough of low pressure over eastern North Carolina is likely expanding south into offshore waters... however as of this writing the latest available NHC TAFB analysis (from 1200Z) does not show the surface trough extended southward yet. Despite this I have relocated this area of interest into offshore waters at 31.5N-78.5W using current satellite observations.

To the northwest... a surface frontal low and its upper trough pivoting into eastern Canada is expected to arc north and away while orbiting the east side of a polar upper vortex diving into Canada. Convergence on the back side of the retreating upper trough will contribute to a steering surface ridge over the eastern US which will push this tropical area of interest west-southwest into northern Florida through 48 hours. After that time the southeastern divergence zone of the Canadian polar upper vortex erodes the steering surface ridge and generates a surface front slowly sagging southeast across the eastern US... turning this tropical area of interest increasingly northwest across the northeastern corner of the Gulf of America and into the United States Gulf coast. The area of interest will be embedded within a warm air mass ahead of the Canadian polar upper vortex and its surface front during its lifecycle... and as such will be below a sprawling warm core anticyclonic upper ridge. This makes for a recipe of possible tropical cyclone formation thanks to high potential of overhead upper anticyclonic outflow. The negatives going against development include land interaction along the forecast path and aforementioned small upper vortex to the northeast chasing this area of interest while pushed around by the upper anticyclone. Over the next 24 hours I have my odds of tropical cyclone formation slightly higher than the NHC's 7-day peak due to the initial organization of the disturbance and as the upper vortex is not likely to overtop the disturbance in the short-term. Recent GFS model data suggests the upper vortex overtops the area of interest with increased northerly shear and then upper outflow suppression after 24 hours. It is possible this disturbance produces enough thunderstorm latent heat release to collapse the upper vortex early... or the GFS is too slow in fading the cool core upper vortex in the midst of the ongoing warm air regime. Due to the current uncertainty in whether or not the upper vortex squashes this area of interest and the forecast track staying close to the Florida panhandle... my odds of tropical development in the northeast corner of the Gulf are at a low 10% as of this update.

Interests across the northern half of the Florida peninsula and far southern Georgia should be aware of an increased risk of widespread thunderstorms capable of producing flash flooding heavy rains over the next 36 hours or so. There is also a slight risk of gusty winds and coastal surf for northeastern Florida and the southeastern corner of Georgia should tropical cyclone formation occur in the short-term. Will provide special updates on this area of interest before my next full update on the Atlantic tropics if odds of short-term tropical cyclone formation increase.

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

IOH 24 Hr Outlook (1200Z Jul 14)... 30% chance of tropical cyclone formation (offshore of northeastern Florida near 30.2N-79.8W)

IOH 48 Hr Outlook (1200Z Jul 15)... 0% chance of tropical cyclone formation (inland northern Florida near 29N-82W)

IOH 72 Hr Outlook (1200Z Jul 16)... 10% chance of tropical cyclone formation (just offshore of the Florida panhandle near 29.8N-84W)

IOH 96 Hr Outlook (1200Z Jul 17)... 0% chance of tropical cyclone formation (inland southeastern Alabama near 31.8N-86W)

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

Formation chance through 48 hours... 0%

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 (Jul 12) CMC Model Run...

**For area of interest #9... surface trough over North Carolina shifts south into offshore waters near 31.5N-79W through 48 hours under influence of surface ridge building over the eastern US... as the steering surface ridge passes to the north the surface trough turns west into inland south Georgia and north Florida through 78 hours and dissipates shortly thereafter

1200Z (Jul 12) ECMWF Model Run...

**For area of interest #9... surface trough over North Carolina shifts southwest into coastal Georgia through 48 hours under influence of surface ridge building over the eastern US... as the steering surface ridge passes to the north the surface trough turns west into inland south Georgia through 84 hours and dissipates shortly thereafter

0000Z (Jul 13) GFS Model Run...

**For area of interest #9... surface trough over North Carolina shifts southwest into inland southern Georgia and northern Florida through 42 hours under influence of surface ridge building over the eastern US... the lowest surface pressures of the trough continues southwest across the Florida panhandle and into the northeast Gulf of America by 57 hours... as the steering surface ridge becomes replaced by surface front slowly advancing southeast across the eastern US the surface trough turns west-northwest into the southeast Louisiana coast by 105 hours... while drifting north along the inland Louisiana/ Mississippi border and toward the surface front the surface trough loses identity to the tail end of the front through 126 hours

1800Z (Jul 12) NAVGEM Model Run...

**For area of interest #9... surface trough over North Carolina shifts south into offshore waters near 31N-79W through 36 hours under influence of surface ridge building over the eastern US and proceeds to evolve into a surface low... as the steering surface ridge passes to the north the surface low proceeds to turn west into the northern Florida peninsula through 78 hours... as the steering surface ridge becomes replaced by surface front slowly advancing southeast across the eastern US the surface low turns west-northwest into waters just offshore of the Florida panhandle through 96 hours and then makes landfall across the panhandle/ far southern Georgia/ far southern Alabama/ southeastern Mississippi by 102 hours while de-generating into an east-west surface trough... the inland east-west surface trough dissipates soon thereafter while continuing north.