By PDC’s Senior Weather
Specialist Glenn James
The Pacific Disaster Center’s (PDC Global) Tuesday, September 5, 2023, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas
Current Tropical Cyclones:
Tropical Cyclone 11E (Jova)…is located approximately 675 NM south of the southern tip of Baja California
Tropical Cyclone 12W (Yun-yeung)…is located approximately 291 NM east of Kadena AB, Okinawa, Japan –
Northeast Pacific Ocean:
Tropical Cyclone 11E Jova
JOVA IN THE MIDST OF RAPID INTENSIFICATION AND ALMOST A HURRICANE
According to the NHC Advisory number 6…
Jova is moving toward the west-northwest near 9 mph (15 km/h), and this general motion with an increase i forward speed is expected through late this week.
Maximum sustained winds have increased to near 70 mph (110 km/h) with higher gusts. Jova has rapidly intensified over the past 24 hours and is expected to continue strengthening rapidly during the next day or two. Jova is likely to become a hurricane overnight and then strengthen to major hurricane intensity by Wednesday night.
Tropical-storm-force winds extend outward up to 80 miles (130 km) from the center.
Central North Pacific…
There are no tropical cyclones, nor any areas of disturbed weather under investigation by the CPHC.
Western Pacific, Indian Ocean and adjacent Seas:
Tropical Cyclone 12W (Yun-yeung)
According to the JTWC Warning number 3…
Sustained winds were 35 knots…with gusts to near 45 knots
Animated enhanced infrared satellite imagery depicts a large area of persistent deep convection obscuring the low-level circulation center (llcc).
Tropical depression 12W is forecast to track northeastward to north-northeastward along the western periphery of the ridge through 96 hours then turn sharply eastward and slow as it rounds the ridge axis.
The ridge is forecast to remain entrenched to the east through most of 12W’s lifecycle and the rapid passage of a mid-latitude shortwave trough over northern Japan near day two is unlikely to significantly affect the ridge or initiate a typical recurve scenario.
Additionally, the baroclinic zone is well north of 40 north, thus the system is not expected to undergo extra-tropical transition. The shortwave trough, however, should boost poleward outflow through 48 hours with a peak intensity of 55 knots anticipated at 48 hours.
After 72 hours, environmental conditions should degrade with dry air entrainment, cooling sea surface temperature values and increasing vertical wind shear leading to a gradual weakening trend through 120 hours. Eventually TD 12W will dissipate near 120 hours as it slows and potentially stalls east of northern Honshu.