MY 2025 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #18

*******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 JUNE 17 2025 1:04 PM EDT...

A tropical disturbance has formed along the east coast of Nicaragua... and will have a tendency to track west-northwest across Central America and a swath of southeastern Mexico and possible into the western Bay of Campeche waters... see area of interest #5 section below for more information. Elsewhere in the Atlantic basin... there are no additional areas of interest being monitored for tropical development.

AREA OF INTEREST #5... Due to the recent collapse of the northwestern Caribbean upper vorticity... an upper anticyclonic ridge currently centered over the west coast of Central America has been allowed to expand. The outflow of the upper ridge is supporting newly-formed eastern Pacific tropical storm Erick and also an increasing low-level spin and associated thunderstorms making landfall on the east coast of Nicaragua as of this writing... the increasing spin has been confirmed by the CIMSS 850 mb vorticity product (https://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor&zoom=&time=). A surface tropical wave of low pressure of African origin... which has been crossing the Atlantic tropical latitudes over the last several days as typically seen with such waves... is also moving into the east coast of Nicaragua and may also be contributing to the coastal Nicaragua spin. The new low pressure spin and eastern Pacific tropical cyclone Erick are expected to move west-northwest in tandem while steered by the southwest edge of the Atlantic surface ridge... note I have shifted the forecast track for this area of interest south due to the initial position of the new spin. The latest model consensus regarding Erick is for the tropical cyclone to make landfall near the Oaxaca/ Guerrero border region in about 48 hours... allowing this area of interest to potentially become the dominant system in the region as it curves increasingly north onto the west coast of the Bay of Campeche (coastal Veracruz). Through much of the 5-day forecast period a west-northwest angle in track is expected due to an additional surface ridge that builds over the eastern US in the wake of a surface frontal system/ upper trough that passes well to the north (across the Central US... Great Lakes... then Atlantic Canada)... with the additional surface ridge a manifestation of the western upper convergence zone of the passing upper trough. The northward turn along west coast of the Bay of Campeche finally happens toward day 5 when this system rounds the west side of the additional surface ridge.

Regarding odds of tropical cyclone formation... assigning a low 10% chance that this system becomes a coastal tropical cyclone on days 4 and 5 as the favorable upper anticyclone is allowed to stay overhead as the current Gulf of America upper vortex is swept east away from the Bay of Campeche while merging with the passing upper trough mentioned toward the end of the previous paragraph. The low odds are a reflection of recent global model runs which have moved away from showing development of this area of interest. Note development beyond day 5 looks increasingly unlikely as the unfavorable upper vortex is currently forecast to then separate from the passing upper trough and retrograde southwest toward this area of interest under the influence of a sprawling warm core upper ridge that builds over the eastern US thanks to the warm southerly flow ahead of a vigorous surface frontal system that develops over the western US in the long range.

Regarding impact to land areas... the most likely impact for the days ahead from this Atlantic basin area of interest is periods of heavy rainfall with flash flooding potential across a swath of Central America (Nicaragua... Honduras... Guatemala... El Salvador... Belize) and a swath of southeastern Mexico (southern Quintana Roo... Campeche... Tabasco... Chiapas... eastern Oaxaca... and Veracruz) as this area of interest tracks west-northwest (then northwest toward day 5) across the region (excess rainfall further southwest... for western Oaxaca and provinces further west... will be more associated with tropical cyclone Erick rather than this area of interest). Within the next 5 days... notable tropical cyclone impacts (such as gusty winds and coastal surf) are currently not likely from this Atlantic basin area of interest due to its currently low odds of tropical cyclone formation. For the south-facing eastern Pacific coasts of Chiapas... Oaxaca... and provinces located further west... please refer to National Hurricane Center products (hurricanes.gov) regarding expected impacts from eastern Pacific tropical cyclone Erick as this site is focused on tropical cyclone impacts from Atlantic basin systems.

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

IOH 24 Hr Outlook (1200Z Jun 18)... 0% chance of tropical cyclone formation (inland over the western part of the Nicaragua/ Honduras border near 13N-87W)

IOH 48 Hr Outlook (1200Z Jun 19)... 0% chance of tropical cyclone formation (inland over Guatemala near 15.8N-90W)

IOH 72 Hr Outlook (1200Z Jun 20)... 0% chance of tropical cyclone formation (inland over the Isthmus of Tehuantepec near 17.5N-94W)

IOH 96 Hr Outlook (1200Z Jun 21)... 10% chance of tropical cyclone formation (coastal Veracruz near 20N-96.2W)

IOH 120 Hr Outlook (1200Z Jun 22)... 10% chance of tropical cyclone formation (coastal Mexico in vicinity of Tamaulipas/ Veracruz border near 22.5N-97.8W)

*****National Hurricane Center (hurricanes.gov) official outlook as of 8 AM 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/).

0000Z (Jun 17) CMC Model Run...

**For area of interest #5... no development shown

1200Z (Jun 16) ECMWF Model Run...

**For area of interest #5... no development shown (model data from more recent 0000Z Jun 17 unavailable before 168 hours... only available for the usually less reliable longer range beyond 168 hours)

0600Z (Jun 17) GFS Model Run...

**For area of interest #5... no development shown

**Current trans-Atlantic upper vorticity string in vicinity of 25N latitude decays into multiple vortices due to prolonged isolation from high-latitude cold air... by 135 hours a surface tropical low emerges near 28N-61.5W due to split flow upper divergence between two of the vortices... after its formation the tropical low is caught in conflicting steering between the Atlantic surface ridge to the east and passing surface ridge to the north associated with convergent back side of upper trough that emerges from Atlantic Canada... however the passing surface ridge has some dominance on the steering which causes the tropical low to drift west to 28.8N-63W by 168 hours

0600Z (Jun 17) NAVGEM Model Run...

**For area of interest #5... Central America tropical low tracks parallel to eastern Pacific tropical cyclone Erick and by 48 hours arrives to southeastern Mexico just west of Guatemala as Erick makes landfall near the Oaxaca/ Guerrero border... through 150 hours tracks slowly northwest and becomes better organized offshore of northern Veracruz... makes landfall at the Veracruz/ Tamaulipas border by 168 hours while degenerating into a surface trough