B. TYPHOON BILLIE (12-18 JULY 1959)
As early as 090000Z, a reconnaissance aircraft was dispatched to investigate a suspect area between the islands of Yap and Koror. However, it was not until 120000Z that a closed surface circulation was confirmed, and at that time a tropical depression warning was issued by JTWC. Within six hours Tropical Depression BILLIE reached tropical storm intensity and twenty-four hours later, at 130600Z, BILLIE was a full-blown typhoon with winds of 65 knots near the center.
From the beginning, BILLIE moved in a northwesterly direction at an average speed of 11 knots. She reached her maximum intensity at 140200Z when surface winds of 100 knots were observed. Later, at 150900Z, reconnaissance aircraft located Typhoon BILLIE approximately 20 miles off the northern tip of Taiwan. She continued to travel in a northwesterly direction and passed inland over the China Mainland at 160000Z, at which time JTWC issued a final warning pending recurvature. Orographic effect took its toll and BILLIE gradually degenerated to a tropical storm, curving abruptly northward. Tracking from land data indicated that BILLIE would enter the Yellow Sea at approximately 32N — 122E. JTWC resumed warnings at 170000Z. The storm center rapidly accelerated and moved through North Korea heading for Vladivostok. By 171800Z cold air advection in connection with a polar front rapidly caused BILLIE to become extra-tropical and the final warning was issued.
Typhoon BILLLIE's movement followed a decided minor sine wave from inception until near the Chinese coast. Elliptical center reports suggested eccentric movement. Originally, BILLIE was forecast to re-
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