Tropical Storm TWENTYTWO Advisory Mon Sep 25

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (TWENTYTWO)
WARNING NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 22W (TWENTYTWO), LOCATED APPROXIMATELY
255 NM SOUTH-SOUTHWEST OF HONG KONG, HAS TRACKED WEST-NORTHWESTWARD
AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A WELL-DEFINED, EXPOSED LOW-LEVEL
CIRCULATION CENTER WITH DEEP CONVECTION DISPLACED OVER THE SOUTHWEST
QUADRANT DUE TO MODERATE NORTHEASTERLY VERTICAL WIND SHEAR (VWS). A
240230Z METOP-B 89GHZ IMAGE REVEALS SHALLOW BANDING WRAPPING INTO
THE CENTER WITH ISOLATED DEEP CONVECTION OVER THE WEST QUADRANT. A
240231Z ASCAT IMAGE SHOWS 25 TO 30 KNOT WINDS, PRIMARILY OVER THE
EASTERN SEMI-CIRCLE. IN ADDITION TO THE ASCAT DATA, DVORAK INTENSITY
ESTIMATES OF T2.0 (30 KNOTS) FROM KNES AND PGTW SUPPORT THE INITIAL
INTENSITY ESTIMATE OF 30 KNOTS. TD 22W IS TRACKING ALONG THE
SOUTHWEST PERIPHERY OF THE LOW-LEVEL SUBTROPICAL RIDGE POSITIONED
OVER SOUTHEAST CHINA.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TD 22W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD THROUGH THE
FORECAST PERIOD, MAKING LANDFALL OVER HAINAN ISLAND NEAR TAU 6 THEN
RE-EMERGING OVER THE GULF OF TONKIN AFTER TAU 12. UPPER-LEVEL
CONDITIONS ARE EXPECTED TO REMAIN MARGINAL WITH PERSISTENT MODERATE
TO STRONG (25 TO 30 KNOTS) NORTHEASTERLY VWS, THEREFORE, TD 22W IS
FORECAST TO MAINTAIN TROPICAL DEPRESSION STRENGTH WINDS THROUGH TAU
24. AFTER TAU 24, THE SYSTEM WILL MAKE LANDFALL OVER NORTHERN
VIETNAM AND WILL RAPIDLY DISSIPATE BY TAU 36. DYNAMIC GUIDANCE IS IN
TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK.//
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