Post-Tropical Cyclone Fernanda / Tropical Cyclone Hilary / Tropical Cyclone 08E (Greg) / Tropical Cyclone 07W (Lan)
Thursday, August 17, 2023

Current Snapshot

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By PDC’s Senior Weather
Specialist Glenn James

The Pacific Disaster Center’s (PDC Global) Thursday, August 17, 2023, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas

Current Tropical Cyclones:

Post-Tropical Cyclone 07E (Fernanda)…is located about 1515 miles west-southwest of the southern tip of Baja California – Last Advisory

Tropical Cyclone 09E (Hilary)…is located about 475 miles south of Cabo San Lucas, Mexico

Tropical Cyclone 08E (Greg)…is located about 480 miles south of Kailua-Kona, Hawaii

Tropical Cyclone 07W (Lan)…is located approximately 243 NM north-northeast of Misawa, Japan – Final Warning


Northeast Pacific Ocean:

Post-Tropical Cyclone 07E (Fernanda) Last Advisory


According to the NHC advisory number 20

The post-tropical cyclone is moving toward the west near 15 mph (24 km/h) and this general motion is expected to continue for the next few days.

Maximum sustained winds have decreased to near 35 mph (55 km/h) with
higher gusts. Continued weakening is forecast during the next couple
of days, and Fernanda is likely to dissipate by the weekend.


Tropical Cyclone 09E (Hilary)


According to the NHC advisory number 6

Hilary is moving toward the west-northwest near 14 mph (22 km/h), and this general motion is expected to continue through tonight. A turn toward the northwest is expected Friday morning, followed by a turn toward the north-northwest and north on Saturday. On the forecast track, the center of Hilary will approach the Baja California peninsula over the weekend.

Maximum sustained winds have increased to near 110 mph (175 km/h) with higher gusts. Additional rapid strengthening is forecast during the next day or so, and Hilary is likely to become a major hurricane later today.

Hurricane-force winds extend outward up to 60 miles (95 km) from the center and tropical-storm-force winds extend outward up to 275 miles (445 km).


RAINFALL: Hilary is expected to produce rainfall amounts of 3 to 6 inches, with isolated maximum amounts up to 10 inches, across portions of the Baja California Peninsula through Sunday night. Flash flooding, locally significant, will be possible.

Heavy rainfall in association with Hilary is expected to impact the Southwestern United States from Friday through early next week, peaking on Sunday and Monday. Rainfall amounts of 2 to 4 inches, with isolated amounts in excess of 8 inches, will be possible across portions of southern California and southern Nevada.

WIND: Tropical storm conditions are expected within the warning area by late Friday, and are possible within the watch area by early Saturday.

SURF: Large swells generated by Hilary will affect portions of the coast of southwestern Mexico and the Baja California peninsula over the next few days. These swells are likely to cause life-threatening surf and rip current conditions.

>>> South of Southern Mexico…

A broad area of low pressure could form offshore of the coast of southern Mexico during the early or middle part of next week.

Some gradual development of this system is possible thereafter while it moves slowly west-northwestward or northwestward.

* Formation chance through 48 hours…low…near 0 percent
* Formation chance through 7 days…low…20 percent


Central Pacific Ocean:

Tropical Cyclone 08E (Greg)


According to the CPHC advisory number 16

The depression is moving toward the west near 13 mph (20 km/h), and this motion is expected to continue for the next day or two.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Greg will continue to gradually weaken over the next day or so, then dissipate by Saturday.

Tropical-storm-force winds extend outward up to 80 miles (130 km) from the center.


Western Pacific, Indian Ocean and adjacent Seas:

Western Pacific…

Tropical Cyclone 07W (Lan) – Final Warning

According to the JTWC Warning number 38

Sustained winds were 40 knots…with gusts to near 50 knots

Animated multi-spectral satellite imagery and a microwave image depict a broad low-level circulation with deep convection sheared over the northwest periphery due to strong (30 knots) southwesterly vertical wind shear.

TS 07W is tracking under strong mid-latitude southwesterly flow and over cool sea surface temperatures while undergoing extra-tropical transition (ett).

The system is forecast to weaken gradually as it tracks northeastward to east-northeastward through 24 hours with decreasing sea surface temperatures, increasing vertical wind shear, and significant dry air. TS 07W will complete ett by 24 hours near the southern tip of Sakhalin Island.