JTWC Report PDF - Weather Underground

TROPICAL STORM BETTY(04W)Tropical Storm Betty originated in theeastern extension of the monsoon trough earlyin July but took several days to develop intoa significant tropical cyclone. Oncedeveloped, Betty moved steadily to the northwestthrough the South China Sea eventuallymaking landfall and dissipating over southernChina.At 0000Z on the 2nd, a disturbance whichlater developed into Tropical Storm Betty waslocated approximately 550 nm (1019 km) southweetof Guam. Synoptic data showed thedisturbance to be a broad, weak surfacecirculation with winds of 10 to 15 kt(5 to 8 m/s). Concurrent satellite imageryshowed the disturbance as an area of poorlyorganized convection. Strong surface ridgingwas present between the disturbance and thedeveloping Tropical Storm Alex (03W) to thenorth which was then located off the eastcoast of Luzon. Above this surface ridginga TUTT was providing good upper-level outflowto the north of the disturbance enhancing theconvective activity.When the disturbance was mentioned onthe 030600Z Significant Tropical WeatherAdvisory (ABEH PGTW), it had moved northwestbehind now Typhoon Alex (03W) which waslocated east of Taiwan and moving rapidlynorthward. With the TUTT providing goodupper-level outflow over the disturbance,the convection exhibited a marked increasein organization and intensity over 24 hoursearlier.By 02002 on the 4th, the disturbancehad moved to ne~r 15N 128E and was becomingmore organized. At this time the first TCFAwas issued on the system. Figure 3-04-1shows the disturbance at the time the TCFAwas issued. Note the banding in the convectionand anticyclonic upper-level outflow.Synoptic data indicated that only a broad10 to 15 kt (5 to 8 m/s) surface circulationwas present. Strong ridging still persistednorth of the disturbance.instrumental in preventingThis ridging wasBetty fromfollowing a path similar to that of TyphoonAlex (03W).F.igluce 3-04-1 Tmpi.d Atom Betty &z .7k tinw tksI@@ TCFA WA .ibbued [0401 162 Juty UMSP V.dlld~w ‘W.27