Contrary to conditions during calm periods in the Atlantic, a large disturbance east of Belize in the northwest Caribbean Sea was designated by the National Hurricane Center (NHC) as Potential Tropical Cyclone 15 (PTC 15) on Friday, October 18 at 5:00 pm ET ). On average, the 14th Atlantic named storm forms on November 19th.
As of 5 p.m. ET, the dispersal center of PTC 15 was located approximately 210 miles east of Belize City, moving west-northwest at 7 mph (11 km/h). Maximum sustained winds were 35 mph (55 km/h). Showers and thunderstorms (convection) remain disorganized but are expanding across the Northwest Caribbean, with some evidence of banding around a broad low-level circulation. For a brief period of about a day before PTC 15 moved inland, conditions were favorable for some limited development. The system is enveloped in a very humid atmosphere (moderate relative humidity of about 75%) and moves over very warm sea surface temperatures (about 30 degrees Celsius (86°F)) with ample deep-sea heat, all of which 5-10 knots in light to moderate windshear.
The four high-resolution intensity models used by NOAA (HWRF, HMON, HAFS-A and HAFS-B models) agreed on Friday morning to designate PTC 15 as a low-to-moderate tropical storm with top sustained winds expected in It will make landfall between 8 a.m. and 2 p.m. EDT Saturday, with speeds of 40 to 60 mph. Friday morning's SHIPS rapid intensification model shows that PTC 15 has a 44% chance of reaching maximum sustained winds of about 65 mph (105 km/h) on Saturday morning, and a 28% chance of reaching 70 mph (115 km/h). km/h). The official NHC forecast, released at 5 p.m. ET on Friday, is more conservative, predicting that PTC 15 will be a minimal tropical storm (maximum sustained winds of about 40 mph or 65 km/h), which is expected to arrive early Saturday afternoon. It often makes landfall along the eastern seaboard of the United States. A reconnaissance flight to PTC 15 is scheduled for Saturday morning. After landfall, steering currents will cause PTC 15 to rapidly dissipate westward and inland.
Regardless of its status, the unrest will bring heavy downpours from northern Belize and Guatemala across southern and eastern Mexico, with rainfall totals of more than 12 inches possible in some areas and increasing the threat of localized flooding.
An area of low pressure is forming in the eastern Yucatan Peninsula, and the National Hurricane Center has classified it as a “Potential Tropical Cyclone 15” (Potential Tropical Cyclone 15) (#PTC15), meaning the system is not yet a tropical storm, but is expected to become one soon and affect land.
Strong ridge… pic.twitter.com/YgV4NnSmJB
— Dr. Levi Cowan (@TropicalTidbits) October 18, 2024
Invest 94L to Hispaniola and the Bahamas
Another Atlantic disturbance, known as 94L, remained chaotic as it pushed westward north of Puerto Rico on Friday afternoon. The environment of 94L is much drier than that of PTC 15, with a mid-level relative humidity of only about 45%, but strong convection persists around the emerging mid-level circulation center. 94L also brings moderate rip current risk to the northern coast of Puerto Rico.
Very warm sea surface temperatures and deep sea heat content of 30-31°C (86-88°F) will favor development, with breeze shear of around 5 knots on Saturday, increasing to around 10 knots by Sunday. 94L's orbit, north of the Greater Antilles, will help reduce land interactions.
Any developments should be canceled as 94L moves into an area of stronger wind shear on Sunday and Monday. Before then, it is not inconceivable that 94L could become a short-lived tropical depression or tropical storm. However, only European models provided any support for this outlook on Friday. The NHC's Tropical Weather Outlook, released at 2 p.m. ET on Friday, noted that the chance of 94L developing is only 20 percent over the 2-day and 7-day periods. The next name on the 2024 Atlantic list after Nadine is Oscar.
Republish our articles for free online or in print under a Creative Commons license.
