MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #60

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

...MONDAY AUGUST 18 2025 5:40 AM EDT...

The Atlantic tropics are still active with Major Hurricane Erin set to continue west-northwest into the waters north of the Bahamas while potentially re-intensifying in the next 24 hours. In addition monitoring other areas of interest in the Atlantic tropics as follows:

(1) See Hurricane Erin section below for an update on the powerful hurricane... including on impacts expected across the northern Caribbean islands including Cuba... Bermuda... the Bahamas... and the east coast of continental North America.

(2) See area of interest #17 section below for a final update on the frontal low midway between North Carolina and Bermuda that the National Hurricane Center was watching for tropical development.

(3) See area of interest #19 section below for a final update on the current north Atlantic frontal cyclone which will no longer be able to acquire tropical character while turning north into cool waters going forward.

(4) See area of interest #20 section below for more information on the tropical wave of low pressure following behind Erin that the National Hurricane Center is monitoring for possible tropical cyclone formation in the days ahead... unlike Erin this system could track directly into the northeastern Caribbean Islands by late this week into the weekend and interests here should monitor the progress of this disturbance.

MAJOR HURRICANE ERIN... For much of Sunday... while moving west-northwest across the waters north of the northeastern Caribbean islands and into the waters just northeast of the southeastern Bahamas... Erin maintained category 3 hurricane strength of 125 mph maximum sustained winds while in the midst of a slowly progressing eye wall replacement cycle. As of 11 PM EDT Erin regained low-end category 4 strength (130 mph maximum sustained winds) as the new eye became increasingly defined in satellite pictures. The sprawling warm core upper anticyclone backed by Erin's thunderstorm latent heat release has fractured the tropical latitude upper vorticity band into one over Florida/ Gulf of America and another in the central tropical Atlantic. It appears upper convergence on the east side of the upper anticyclone and west side of the central Atlantic upper vorticity has expanded the west nose of the Atlantic surface ridge... for instance the 1016 mb isobar of the ridge has been shifted west in recent NHC TAFB surface analyses. This is probably behind Erin's more west and less north track in recent hours... and my updated forecast track below assumes this will continue for another 24 hours and thus is a little southwest of this past 0000Z GFS model run. After 24 hours a north turn should finally occur once Erin is gravitated toward the surface ridge weakness associated with the tail end of the surface front containing areas of interest #17 and #19. Through the 48 hour period Erin reaches the warmest waters along its forecast track (30 deg C per the data at https://www.nhc.noaa.gov/sst/) and the vast upper anticyclone keeping shear low and upper outflow high remains intact above all quadrants of the hurricane as the mid-latitude upper vorticity band along 35N latitude splits in half... the eastern half which is ingested into the upper trough associated with area of interest #19 and the western half remaining distant while stuck over North Carolina/ Tennessee. Therefore I believe the max potential intensity through 48 hours is category 5. In recent colorized infrared satellite frames Erin is looking well organized rather quickly with an increasingly symmetrical central dense overcast around the increasingly defined new eye... and I forecast Erin to reach a category 5 peak stronger than its first in the next 24 hours. I then project another eye wall replacement cycle and lower the intensity a notch to high-end category 4 status by 48 hours.

The long-range fate of Erin... after 48 hours... hinges upon a currently materializing bi-polar upper vortex which will result from the merger between the current eastern Canada and northwestern Atlantic upper troughs. As the elongated upper vortex initially materializes it will have a northwest-southeast tilt... this tilt angle is usually associated with high upper divergence to the east and indeed a rapidly forming frontal cyclone will be born over Newfoundland in 24 hours which will shift into the north Atlantic as the forecast period progresses. Previous model projections had this frontal cyclone pull enough cold air south such that the northwestern center of the cold core bi-polar upper vortex would be pulled south closer to Erin. As of late the models keep the northwestern center of the bi-polar upper vortex away while the surface frontal cyclone simply ingests the cold air of the southeastern center. Despite this... Erin is still expected to turn northeast across the northwestern Atlantic waters due south of Atlantic Canada due to the approach of a shortwave upper trough from the northern US. With time Erin pulls the cold air associated with the shortwave upper trough southward... which causes it to become a more bonafide amplified upper trough with increasing upper divergence that should slow the weakening rate of Hurricane Erin despite shearing the hurricane. After day 5 transition into a hurricane-force non-tropical remnant frontal cyclone supported by the amplifying upper trough should be completed as Erin speeds into cooler water. Note the long range forecast track for Erin's remnant cyclone has shifted to a more east and less north angle as Erin is now expected to interact with a gradually amplifying upper trough instead of the already amplified flow around the aforementioned bi-polar upper vortex.

Regarding the impact to land areas:

(1) Heavy rainfall from Erin's southern outer bands is over Haiti and the Dominican Republic where flash flooding and mudslides over mountainous terrain cannot be ruled out... and is spreading into the southeastern Bahamas. Outer bands of heavy rainfall will spread into the central Bahamas and possibly eastern Cuba through 24 hours. Gusty winds are also possible across the southeastern and central Bahamas over the next 24 hours given the latest westward-nudged forecast track.

(2) Erin as a powerful hurricane at first... then as a large and still powerful non-tropical frontal cyclone after day 5... will produce widespread surf across the western Atlantic. Surf is currently affecting the shores of the northeastern Caribbean Islands... Bahamas... and Cuba. Surf will reach the shores of the southeastern United States coast and Bermuda by 24 hours. And by Thursday through Saturday surf should reach the shores of the northeastern United States and Atlantic Canada

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

0 Hr Position (0600Z Aug 18)... 130 mph maximum sustained wind major hurricane centered just northeast of the southeastern Bahamas at 22.6N-69.9W

IOH 24 Hr Forecast (0600Z Aug 19)... 170 mph maximum sustained wind major hurricane centered just northeast of the central Bahamas at 25N-73W

IOH 48 Hr Forecast (0600Z Aug 20)... 150 mph maximum sustained wind major hurricane centered offshore of the southeastern United States at 28.5N-74W

IOH 72 Hr Forecast (0600Z Aug 21)... 140 mph maximum sustained wind major hurricane centered east of the Carolinas at 32.5N-73.5W

IOH 96 Hr Forecast (0600Z Aug 22)... 115 mph maximum sustained wind major hurricane centered midway between Cape Cod Massachusetts and Bermuda at 37.5N-67.5W

IOH 120 Hr Forecast (0600Z Aug 23)... 85 mph maximum sustained wind hurricane transitioning into a hurricane-force remnant frontal cyclone while centered south-southwest of Newfoundland at 40N-57W

*****National Hurricane Center (hurricanes.gov) official forecast of 11 PM EDT***********************

Peak Strength (1200Z Aug 18)... 145 mph maximum sustained wind major hurricane centered just northeast of the southeastern Bahamas at 23.2N-70.2W

5-Day Position (0000Z Aug 23)... 90 mph maximum sustained wind hurricane centered south of Newfoundland at 41.4N-56.7W

AREA OF INTEREST #17... Up until only recently the National Hurricane Center continued to mention the western Atlantic frontal low (positioned near 34N-70W as of 0600Z) in their tropical weather outlook... so providing one final update on this feature in this update. It is apparent that conditions are no longer favorable for tropical development due to increased westerly shear imparted by upper vorticity from the eastern US that has settled along 35N latitude... the shear has displaced the small pockets of thunderstorms well east of the swirl center. The National Hurricane Center finally removed this feature from their tropical weather outlook as of 2 AM EDT. The innocuous frontal low should continue east-southeast with the aid of the surface ridge descending from eastern Canada up until it loses its identity due to the encroaching low pressure field of Hurricane Erin to the south. This is my final statement on this area of interest on this blog.

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

IOH 24 Hr Outlook (1800Z Aug 17)... 0% chance of tropical cyclone formation (just north-northwest of Bermuda near 33N-65.5W)

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

Not in the official outlook

AREA OF INTEREST #19... The current north Atlantic frontal cyclone did not acquire tropical characteristics while lacking a persistent core of showers and thunderstorms. Going forward the northwest Atlantic upper trough supporting the surface cyclone becomes the southeastern center of a bi-polar upper vortex while the current upper trough over eastern Canada become the northwestern center. The divergence maximum of the NW/SE tilted elongated upper vortex will be to the west of the surface cyclone... resulting in a more dominant surface cyclone to the west. Meanwhile this surface cyclone takes an arcing path into cooler open north Atlantic waters while steered in the flow around the east side of the bi-polar upper vortex and then the dominating surface cyclone... and the models agree on this surface cyclone losing its identity along the warm front extending east from the dominating surface cyclone. Tropical development is no longer possible with the future path going straight into waters well below 26 deg C... and this is my final statement on this area of interest on this blog.

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

IOH 24 Hr Outlook (0600Z Aug 19)... 0% chance of subtropical cyclone formation (north Atlantic near 47.5N-39W)

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

Not in the official outlook

AREA OF INTEREST #20... About 24 hours ago the National Hurricane Center introduced a new area of interest in their tropical weather outlook for the eastern and central tropical Atlantic... and as of Sunday pinpointed it to the tropical wave of low pressure that emerged from western Africa Friday/ Saturday with the wave axis analyzed by the NHC TAFB to be along 25W longitude as of earlier tonight. It appears the wave has become a southwest to northeast oblong gyre while absorbing energy left behind by the adjacent tropical wave which is nearing 50W longitude as of this writing. In the upper-levels an inverted upper trough is forming to the west which should continue west and away while revolving around the south side of Hurricane Erin's upper anticyclone. During my previous update on the Atlantic tropics northward warm air transport ahead of the current northeast Atlantic deep-layer low locally displaced the warm core regional tropical upper ridge axis northward into northwestern Africa... resulting in another inverted upper trough to the east which will be chasing this tropical wave while embedded in the easterlies on the south side of the upper ridge axis. The inverted upper trough to the east however does not catch up to this wave... in all keeping the surface tropical wave of interest under favorable upper anticyclonic outflow in between the inverted upper troughs during the forecast period. However the global models wait to develop the wave in the long range... perhaps while projecting the wave will first need to reach lower concentrations of dry Saharan air toward the west... as a result the NHC odds of tropical cyclone formation are 0% in the short-term and above zero for the longer term.

For this update I am initializing this area of interest at the approximate centroid of the oblong gyre at 12N-31W... in the vacuous area between the scattered thunderstorms beside the Republic of Cabo Verde Islands and large circular area of thunderstorms toward the southwest. In recent hours nighttime infrared suggests increasing rotation in the low clouds at the northeast edge of the circular thunderstorm mass... therefore I have gone ahead and issued odds of tropical cyclone formation above 0% for the short term but have kept them below 50% due to the lack of models showing short-term development and in case dry Saharan air indeed disrupts short-term development. My longer term odds are already above 50% as the global models are coming into increasing agreement on developing this system by day 5 and beyond. My forecast track is based on the southwestern area of the oblong gyre developing near the circular thunderstorm mass... which results in an initial west track along 12N latitude as the cyclonic flow of the remainder northeastern part of the gyre keeps the developing circulation suppressed to the south. In this scenario... the remainder northeast part of the gyre vaults west to a position northwest of the developing circulation while channeled in vigorous easterlies between the developing circulation and Atlantic surface ridge. After 48 hours I begin to lift the track of the developing circulation on a more north angle at first due to the tug of the remainder gyre to the northwest... then due to the developing circulation reaching the weakened west part of the Atlantic surface ridge induced by the presence of Erin. By day 5 Erin's ridge weakness may close as it lifts northeast toward the north Atlantic... thus I do not show a turn to the north through day 5.

Interests in the northeastern Caribbean Islands (northern Lesser Antilles... Virgin Islands... and Puerto Rico) should be aware of this disturbance for possible heavy rainfall... gusty wind... and coastal surf impacts by late this week into the weekend.

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

IOH 24 Hr Outlook (0600Z Aug 19)... 10% chance of tropical cyclone formation (eastern tropical Atlantic near 12N-36W)

IOH 48 Hr Outlook (0600Z Aug 20)... 30% chance of tropical cyclone formation (central tropical Atlantic near 12N-41.5W)

IOH 72 Hr Outlook (0600Z Aug 21)... 50% chance of tropical cyclone formation (central tropical Atlantic near 14N-48.5W)

IOH 96 Hr Outlook (0600Z Aug 22)... 60% chance of tropical cyclone formation (east of the Lesser Antilles near 16N-55.5W)

IOH 120 Hr Outlook (0600Z Aug 23)... 60% chance of tropical cyclone formation (beside the northern Lesser Antilles near 17.5N-61.2W)

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

Formation chance through 48 hours... 0%

Formation chance through 7 days... 50%

...COMPUTER MODEL SUMMARY...

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

1200Z (Aug 17) CMC Model Run...

**For Major Hurricane Erin... continues west-northwest and passes just northeast of the southeastern Bahamas by 18 hours... subsequently curves north into the waters between North Carolina and Bermuda by 90 hours... then turns northeast toward a north Atlantic frontal cyclone that is born over Newfoundland and by 168 hours absorbs it while itself becoming an exceptionally large and powerful non-tropical remnant frontal cyclone centered at 50.5N-33.5W

**For area of interest #17... frontal low between Bermuda and North Carolina continues drifting east-southeast and loses its identity to Hurricane Erin incoming from the south after 36 hours

**For area of interest #19... the surface layer of the north Atlantic deep-layer cyclone continues northeast and while midway between the south tip of Greenland and the British Isles at 84 hours loses identity along warm front extending east from the developing frontal cyclone over Newfoundland/ North Atlantic.

**For area of interest #20... eastern Atlantic tropical wave initialized as a SW/NE trough to the southeast of the Republic of Cabo Verde Islands... while continuing west the trough tilt becomes increasingly north-south as it continues across the tropical Atlantic and by 126 hours the trough axis arrives to the northern Lesser Antilles islands and extends into the waters to the north of the islands... north apex of the surface trough becomes a tropical low near 22.5N-64.5W at 150 hours... proceeds to become a tropical cyclone while continuing northwest to 24N-65.8W through 168 hours

**Currently weak tropical wave nearing west coast of Africa moves offshore and becomes a tropical low centered just west of the Republic of Cabo Verde Islands at 78 hours... tropical low moves west-southwest to 13N-37W through 138 hours... tropical low then turns west-northwest to 15N-41.5W through 168 hours

1200Z (Aug 17) ECMWF Model Run...

**For Major Hurricane Erin... continues west-northwest and passes just northeast of the southeastern Bahamas by 18 hours... subsequently curves north into the waters between North Carolina and Bermuda by 96 hours... then turns northeast toward a north Atlantic frontal cyclone that is born over Newfoundland and by 168 hours absorbs it while itself becoming an exceptionally large and powerful non-tropical remnant frontal cyclone centered at 50N-36W

**For area of interest #17... frontal low between Bermuda and North Carolina continues drifting east-southeast and loses its identity along the front while positioned just northwest of Bermuda at 42 hours

**For area of interest #19... the surface layer of the north Atlantic deep-layer cyclone continues northeast and while midway between the south tip of Greenland and the British Isles at 90 hours loses identity along warm front extending east from the developing frontal cyclone over Newfoundland/ North Atlantic.

**For area of interest #20... continues across the eastern and central tropical Atlantic as a large tropical low which finally consolidates into a smaller tropical low near 18N-57W at 114 hours... the tropical low passes just north of the northern Lesser Antilles at 138 hours with tropical cyclone formation suggested near 20.5N-64.8W at 150 hours... tropical cyclone positioned at 22N-67W (east of the southeastern Bahamas) at 168 hours

0000Z (Aug 18) GFS Model Run...

**For Major Hurricane Erin... continues west-northwest and passes just northeast of the southeastern Bahamas by 12 hours... subsequently curves north into the waters between North Carolina and Bermuda by 81 hours... then turns northeast toward a north Atlantic frontal cyclone that is born over Newfoundland and while itself transitioning into a large and powerful non-tropical remnant frontal cyclone reaches the northeast Atlantic near 49N-30W at 168 hours

**For area of interest #17... frontal low between Bermuda and North Carolina continues drifting east-southeast and loses its identity along the front while positioned just northwest of Bermuda at 51 hours

**For area of interest #19... the surface layer of the north Atlantic deep-layer cyclone continues northeast and while midway between the south tip of Greenland and Iceland at 81 hours loses identity along warm front extending northeast from the developing frontal cyclone over Newfoundland/ North Atlantic.

**For area of interest #20... continues across the eastern and central tropical Atlantic as a large tropical low which finally consolidates into a smaller tropical low near 15N-55.2W at 87 hours... while moving west-northwest into the northern Lesser Antilles through 111 hours becomes a tropical cyclone... continues west-northwest into the Virgin Islands through 120 hours as a tropical storm... center of tropical storm continues west-northwest along the north coast of Puerto Rico through 129 hours then becomes disrupted into a multi-center tropical low while moving into the mountainous terrain of the northern Dominican Republic through 144 hours... re-consolidates into a single-center tropical depression between Haiti and the southeastern Bahamas at 153 hours... begins to briskly strengthen as a compact tropical storm between eastern Cuba and the Bahamas by 168 hours

1800Z (Aug 17) NAVGEM Model Run...

**For Major Hurricane Erin... continues west-northwest and passes just northeast of the southeastern Bahamas by 24 hours... subsequently curves north into the waters between North Carolina and Bermuda by 90 hours... then turns northeast toward a north Atlantic frontal cyclone that is born over Newfoundland and by 168 hours absorbs it while itself becoming an exceptionally large and powerful non-tropical remnant frontal cyclone centered at 51N-34W

**For area of interest #17... frontal low between Bermuda and North Carolina continues drifting east-southeast and loses its identity to Hurricane Erin incoming from the south after 24 hours

**For area of interest #19... the surface layer of the north Atlantic deep-layer cyclone continues northeast and while south-southwest of Iceland at 102 hours loses identity along warm front extending northeast from the developing frontal cyclone over Newfoundland/ North Atlantic.

**For area of interest #20... continues across the eastern and central tropical Atlantic as a large tropical low which finally consolidates into a smaller tropical low near 15.5N-48W at 96 hours... tropical low reaches position east of the northern Lesser Antilles (17N-56.5W) by 168 hours

**Large tropical wave begins to move off the west coast of Africa at 90 hours as a large gyre... northward-moving smaller low develops in east side of the gyre and is positioned just east of the Republic of Cabo Verde Islands at 168 hours