MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #42

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

...TUESDAY JULY 22 2025 6:19 PM EDT...

For the tropical latitudes of the Atlantic basin... time has ran out for development of the tropical wave of low pressure currently approaching the southern Lesser Antilles islands as westerly wind shear is expected to increase soon... see area of interest #10 section below for details. For the tropical wave that recently departed the west coast of Africa... upper winds appear more favorable for possible development as it treks west across the open Atlantic tropic as the region of upper vorticity negatively affecting area of interest #10 shifts northwest and away while gravitating toward the upper trough currently entering the northwest Atlantic. However none of the models develop this wave... and the northern half of the wave has already lost thunderstorms squalls while ingesting dry Saharan air... therefore I have not upgraded this tropical wave to an area of interest.

For the mid-latitudes of the Atlantic basin... a broad surface low pressure area is materializing in the vicinity of northern Florida from the fusion between the tail end of a surface cold front and pre-frontal surface trough. Watching for signs of development as the broad surface low proceeds west across the northeastern Gulf of America... in the direction of southeast Louisiana... through Friday. See area of interest #11 section below for details.

AREA OF INTEREST #10... Based on visible satellite animation... the maximum spin of the surface tropical wave of low pressure moving west across the central tropical Atlantic reached 12.5N-54W as of 1800Z. This is a touch slower than the previous forecast track and so my updated one is adjusted accordingly. The tropical wave has continued to struggle in maintaining organized thunderstorm activity due to a combination of the dry Saharan air lurking to the north and the open Atlantic upper vorticity that is descending south toward the tropical wave under the force of the current north Atlantic upper ridge... with this upper vorticity increasingly resisting the northern outflow of the tropical wave. Going forward the current southeastern US upper ridge will expand due to northward warm air transport ahead of a frontal system ejecting from western Canada... and the expanding upper ridge will push the tail end of the Atlantic upper vorticity southwest toward the northern Lesser Antilles and even closer to this tropical wave... this will result in increasing westerly shear across the wave and at this point time has ran out for the wave to develop. As the wave then continues across the Caribbean conditions will continue to be unfavorable for development as the expanding southeast US upper ridge fuses together the Atlantic upper vorticity to the northeast... upper vorticity separated from the northwest Atlantic upper trough to the north... and northwestern Caribbean upper vorticity to the northwest at a location overtop the tropical wave. Noting some model runs eventually develop this wave in the eastern Pacific after it escapes all the unfavorable upper vorticity... however this is beyond the jurisdiction of this site where I focus on Atlantic tropical activity. As a result this will be my final statement on this area of interest on this blog.

Noting the southern Lesser Antilles may see increased heavy rainfall from the tropical wave in the next 24 hours as the westerly shear may not be strong enough to completely decouple the thunderstorms from the tropical wave.

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

IOH 24 Hr Outlook (1800Z Jul 23)... 0% chance of tropical cyclone formation (southern Lesser Antilles near 13N-60.5W)

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

Not in the official outlook

AREA OF INTEREST #11... It has been hard to establish a center fix for this area of interest... yesterday I had positioned it along the southwest end of a pre-frontal surface trough offshore of the southeastern United States where a thunderstorm complex appeared to initiate a spin. Since then the spin lost its identity overnight and the northeast half of the pre-frontal surface trough has merged with the cold front being driven by the current Atlantic Canada frontal cyclone. Meanwhile the southwest part of the surface trough is shown to have moved west into northern Florida thru today's 1200Z NHC TAFB surface analysis due to the steering provided by the surface ridge expanding behind the Atlantic Canada frontal cyclone... this position is well west of my previous forecast track. Noting the remainder north Florida surface trough also appears to be merging with the tail end of the cold front... with the merger resulting in what appears to be a broad surface low whose outer circulation is producing thunderstorm bursts as of this afternoon with the aid of the upper outflow provided by the ongoing southeastern US upper ridge... curiously the inner area of this circulation is vacuous while lacking thunderstorms. For today's forecasting I have fixed the initial position of this area of interest at the centroid of the oblong vacuous area... which is just offshore of northeast Florida and still west of my previous forecast track. The updated forecast track in the outlook below is adjusted accordingly... calling for an initial west to west-southwest track around the steering surface ridge. Later in the forecast period the steering surface ridge is then re-enforced by the western convergence zone of the upper trough now ejecting from western Canada... however a gradual bend/ turn to the north eventually occurs as this disturbance rounds the southwest side of the ridge.

The adjusted forecast track keeps this system farther from the upper vortex currently near the central Bahamas... and any upper vorticity left behind by the northwest Atlantic upper trough... with the upper vorticity to approach from the east under the force of the southeast US upper ridge. Moreover there is less upper vorticity forecast to be in the environment of this area of interest as the northwest Atlantic upper trough leaves less behind than shown in the models in previous days. The implication is that there will be less northeasterly shear over this disturbance than previously forecasted... however I have only slightly raised my peak odds of tropical cyclone to 15% due to the initial broad structure of the surface low which will tend to have a hard time establishing a better-defined center needed for focusing thunderstorms and tropical development.

Regarding impact to land areas... pockets of thunderstorms featuring heavy rainfall with flash flooding potential have developed across coastal South Carolina... southern Georgia... south Florida... and the panhandle of Florida... while northern Florida is currently calm as of this writing while positioned in the aforementioned vacuous area. Going forward... as this system continues west... expecting periods of heavy rainfall for Florida... southern Georgia... southern Alabama... southern Mississippi... and south-central to southeastern Louisiana thru Thursday (this is a larger area than previously mentioned due to the initially larger state of this area of interest... and also less northeasterly shear which will allow for thunderstorm activity in the northern quadrants of the circulation). By Friday... as this system makes landfall... the heavy rainfall potential expands across the remainder of Louisiana and Mississippi... as well as the southeast half of Arkansas. For the United States Gulf coast region from the Florida panhandle to southeast Louisiana... the wind and coastal surf probability currently remains low due to the current low probabilities of tropical cyclone formation.

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

IOH 24 Hr Outlook (1800Z Jul 23)... 10% chance of tropical cyclone formation (central Florida panhandle coast near 29.9N-85.8W)

IOH 48 Hr Outlook (1800Z Jul 24)... 15% chance of tropical cyclone formation (far northern Gulf of America just south of the Mississippi/ Louisiana border and just east of southeastern Louisiana near 29.5N-88.8W)

IOH 72 Hr Outlook (1800Z Jul 25)... 0% chance of tropical cyclone formation (interior northern section of Louisiana/ Mississippi border region near 32.5N-91W)

*****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/).

1200Z (Jul 22) CMC Model Run...

**For area of interest #10... no Atlantic basin development shown (in long range the tropical wave shown to develop in the eastern Pacific)

**For area of interest #11... surface trough currently over northern Florida proceeds west-southwest into the northeastern Gulf of America through 42 hours... turns west-northwest into southern Louisiana through 66 hours and dissipates shortly thereafter

0000Z (Jul 22) ECMWF Model Run...

**For area of interest #10... no development shown

**For area of interest #11... no development shown

1200Z (Jul 22) GFS Model Run...

**For area of interest #10... no Atlantic basin development shown (in long range the tropical wave shown to develop into an eastern Pacific tropical low by 168 hours)

**For area of interest #11... current north Florida surface trough shown to move west-southwest into the waters just offshore of southeast Louisiana through 45 hours... shortly thereafter turns northwest into southeast Louisiana then dissipates

1200Z (Jul 22) NAVGEM Model Run...

**For area of interest #10... no development shown

**For area of interest #11... current north Florida surface trough shown to move west-southwest into the waters just offshore of southeast Louisiana through 54 hours... shortly thereafter turns northwest into southeast Louisiana then dissipates