JULY 16 - AUGUST 3, 1973 (HURRICANE DOREEN)

The disturbed area that developed into Hurricane DOREEN was first located by satellite at 16/1600Z on the Intertropical Convergence Zone near 9N 101W. It showed some signs of a closed circulation. A nighttime infrared photograph at 17/0400Z indicated that the disturbance was moving west at 10 knots and becoming better organized. By 1800Z satellite pictures placed the circulation center near 9N lO5W, but reports from the KAPAA, HOEGH DYKE, and the AKADEMIC KOROLYOV indicated that the center was 20 farther north. By this time a tropical depression had formed, and advisories were started.

Development was rapid. The AKADEMIC KOROLYVO reported 30-knot winds at 18/0000Z suggesting that a tropical storm had formed near 10.5N 107W, about 120 nautical miles east of Clipperton Island. The AMERICAN CORSAIR reported 38-knot winds and 15- foot seas at 0600Z, confirming observations at 0600Z and 0900Z from the SHAMALY. An Air Force reconnaissance aircraft measured 60-knot winds at 18/2230Z; considering the rate of development, the storm was classified as a hurricane at 19/0000Z.

It was moving west-northwestward about 12 knots. The AMERICAN CHALLENGER passed to its south during the night of the 18th. The HOEGH DYKE, heading west, passed in front of the storm on the 19th reporting 40-knot winds. Both vessels were about 150 nautical miles from the center. Reconnaissance aircraft at that time measured winds of 90 knots and a central pressure of 973 mb (28.73").

DOREEN continued on its course well out of range of surface vessels. Aircraft reported maximum winds of 120 knots at 20/1920Z, 80 knots at 21/1806Z, 85 knots at 22/1825Z, and 69 knots at 23/1800Z, near 15N 133W. Reconnaissance priority after the 23rd was directed toward hurricane EMILY, nearer to the more heavily traveled shipping lanes off Manzanillo, Mexico. Wind speeds in DOREEN were in the 55-70 knot range after 23/1800Z. DOREEN passed 140W at 16.3N on a westward course shortly before 25/1800Z.

A frontal system between two portions of the North Pacific high pressure area weakened as DOREEN moved closer to Hawaii and the two cells merged with the main center about 1,000 miles northwest of Honolulu. The high center then moved eastward forcing DOREEN southwestward on the 27th to near 12.5N 150W by 28/1800Z. The storm then changed course to west-northwest at 810 knots.

On the afternoon of the 27th the 144-foot Greek ship CORNELIA sailed into DOREEN's path, calling for help when it lost its rudder while being lashed by 52-knot winds and 35-foot waves. A sea level pressure of 971 mb (28.67") was reported. The ship managed to clear the storm and continued on its way to Panama, deciding not to return to Honolulu with Coast Guard assistance.

Before the dip to lower latitudes, DOREEN had been classified as a tropical storm, but hurricane winds developed again on the 28th and continued until 0600Z on August 1. The hurricane passed 300 miles south-southwest of South Point, Hawaii on the afternoon of the 30th. On the afternoon of the 29th, a 9 foot open ocean swell and 3-1/2 foot surf generated by DOREEN had been observed at Kapoho, the easternmost town on the island of Hawaii.

Deterioration of the storm was rapid west of 165W. Winds decreased to 60 knots near 18N 166W by 01/1200Z; and to 35 knots at 20N 171W by 02/1200Z. The system was a depression with 30-knot winds by 03/0000Z. Advisories were discontinued, and the remaining vortex of the storm dissipated under an upper air trough as it crossed the Date Line.

DOREEN's abrupt southwestward movement on the 27th and 28th and its subsequent redevelopment to hurricane intensity were unusual. The system had a long life of 18 days, and covered a distance of 4,200 nautical miles. Except during the redevelopment period on the 27th, it followed the forecast track. DOREEN's path was similar to that of hurricane CELESTE in August 1972.

No unusual weather events were reported in the Hawaiian Islands or at Johnston Island as DOREEN bypassed them.

SEPTEMBER 27 - OCTOBER 8, 1973 (HURRICANE KATHERINE)

Squally areas of showers and thunderstorms about 400 miles south of Zihuantenejo, Mexico on September 27 drifted west and increased on the 28th. A cyclonic circulation developed just north of Clipperton Island by the morning of the 29th. Satellite pictures at 29/1800Z suggested intensification had continued, with development into tropical storm KATHERINE. The MOUNT PARK, southeast bound and north of the center, experienced 10- 20 knot veering winds.

The storm moved northwest at 10-12 knots and was tracked by successive satellite pictures on account of a lack of nearby ship reports. The SHEAF TYNE's reports from 200-300 miles south of the center on the 30th and October I indicated the storm's presence.

An infrared picture at, 01/0435Z showed a well-developed hurricane near 14.ON 116.5W. The system developed maximum winds of 85 knots near 16N 118W by 02/0000Z and continued at that strength to near 17N 121W by 03/0000Z. Weakening began as the hurricane continued westward at 15 knots, and it became a tropical storm near 17N 127W at 04/0000Z.

The storm then moved west-southwest at 10-12 knots to 14N 140W by 06/1800Z when advisory responsibility was transferred to the CPHC at Honolulu.

It moved west at 12 knots with winds of 40-50 knots during the daylight hours of the 7th, weakening to 35 knots during the night of the 7th and to a depression with 30-knot winds earlv on the 8th. It dissipated under a cold upper trough near 14N 148W soon after 1800Z on the 8th.

Vessels reporting from the periphery of the cyclone during its latter stages included the EXPORT BANKER, PIONEER, CONTENDER, TOKUYO MARU, and non-AMVER-listed vessels BLHD, FNAW, GLHF, and UNDK.