Tropical Storm TWENTYTWO Advisory Paz, 24.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 20W (TWENTYTWO)
WARNING NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 22W (TWENTYTWO), LOCATED APPROXIMATELY 223 NM
SOUTH OF HONG KONG, HAS TRACKED WEST-NORTHWESTWARD AT 22 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS AN AREA OF FLARING CONVECTION STILL STRUGGLING TO ORGANIZE
AS EASTERLY FLOW ALOFT DISPLACES THE CONVECTION TO THE SOUTHWEST. A
231402Z METOP-B ASCAT IMAGE SHOWS AN ASYMMETRIC AND ELONGATED LOW
LEVEL CIRCULATION CENTER  WITH A BROAD REGION OF 20 TO 25 KNOT WINDS
ON THE NORTHERN PERIPHERY AND A FEW 30 KNOT BARBS ON THE SOUTHWEST
QUADRANT NEAR THE SYSTEM CENTER. MORE RECENT SHIP AND SURFACE
OBSERVATIONS FROM HONG KONG INDICATE WINDS IN EXCESS OF 25 KNOTS,
AND THESE DATA ARE THE BASIS FOR THE INITIAL 30 KNOT INTENSITY.
UPPER-LEVEL ANALYSIS INDICATES FAIRLY STRONG EASTERLY FLOW FROM A
WELL ESTABLISHED NORTHERN RIDGE, YET ONLY MODERATE TO LOW VERTICAL
WIND SHEAR AS THE SYSTEM MOVES SWIFTLY IN PHASE WITH THE UPPER-LEVEL
PATTERN. SSTS IN THE REGION ARE ALSO FAVORABLE NEAR 30 CELSIUS.
CURRENTLY TD 20W IS TRACKING WEST-NORTHWESTWARD ALONG THE SOUTHERN
BOUNDARY OF A MID-TO-LOW LEVEL SUBTROPICAL RIDGE ANCHORED OVER
TAIWAN.
3. FORECAST REASONING.
   A. THIS IS THE FIRST WARNING ON THIS SYSTEM AND ESTABLISHES THE
FORECAST REASONING.
   B. TD 20W WILL CONTINUE TO TRACK GENERALLY NORTHWESTWARD OVER THE
NEXT 48 HOURS AS THE SUBTROPICAL RIDGE BUILDS EXTENDING WESTWARD
OVER CHINA. THE RAPID SPEED OF ADVANCE WILL CONTINUE TO MINIMIZE
SHEAR FROM THE UPPER-LEVEL EASTERLIES, HOWEVER, THERE WILL BE
INSUFFICIENT TIME FOR THE SYSTEM TO CONSOLIDATE SIGNIFICANTLY AS IT
TRAVERSES OVER THE WARM WATERS OF THE SOUTH CHINA SEA. TD 20W IS
EXPECTED TO INTENSIFY TO 35 KNOTS UNDER THE FAVORABLE CONDITIONS
OVER THE NEXT 12 HOURS BEFORE MAKING LANDFALL OVER HAINAN, AND
REEMERGING OVER THE GULF OF TONKIN BY TAU 24. LAND INTERACTION WITH
HAINAN WILL BEGIN TO WEAKEN THE SYSTEM BEFORE MAKING LANDFALL AGAIN
OVER NORTHERN VIETNAM. THE SYSTEM WILL CONTINUE TO TRACK INLAND
DISSIPATING BY TAU 48. DYNAMIC MODEL GUIDANCE SHOWS FAIRLY GOOD
AGREEMENT, LENDING HIGH CONFIDENCE IN THE FORECAST TRACK.//
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