WDPN31 PGTW 222100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W (NINETEEN) 
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.1N 117.0E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 275 NM NORTHWEST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 22 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS DEEP
CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC) OF
TROPICAL DEPRESSION (TD) 19W. WATER VAPOR IMAGERY REVEALS DRY AIR
TO THE NORTH AND WEST OF THE DEEP CONVECTION. UPPER-LEVEL
DIFFLUENCE IS ENHANCED TO THE SOUTHWEST. THE INITIAL POSITION IS
PLACED WITH LOW CONFIDENCE BASED ON THE CONCEALED LLCC HIDDEN UNDER
DEEP CONVECTION. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH
LOW CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED
BELOW.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: ALONG THE SOUTHERN EDGE OF A
SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 34 KTS AT 221721Z
   CIMSS ADT: 28 KTS AT 221730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: LOW
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TD 19W WILL TRACK WESTWARD UNDER THE STEERING
INFLUENCE OF A SUBTROPICAL RIDGE TO THE NORTH FOR THE REMAINDER OF
THE FORECAST PERIOD. BETWEEN TAU 48-72, THE SYSTEM WILL MAKE
LANDFALL ON THE EAST COAST OF VIETNAM. ENVIRONMENTAL CONDITIONS
WILL BE FAVORABLE FOR DEVELOPMENT DURING THE FIRST 40 HOURS OF THE
FORECAST. VERTICAL WIND SHEAR WILL REMAIN LOW AND UPPER-LEVEL
DIVERGENCE WILL FLOW EQUATORWARD. OCEAN HEAT CONTENT (OHC) EAST OF
110E IS HIGH, HOWEVER THE OHC DECREASES WESTWARD DESPITE WARM (26C)
SEA SURFACE TEMPERATURES. THE FAVORABLE ENVIRONMENT WILL ALLOW TD
19W TO REACH A PEAK OF 75KTS BY TAU 48. AFTER LANDFALL, TD 19W WILL
GRADUALLY WEAKEN TO DISSIPATION BY THE END OF THE FORECAST PERIOD.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT THAT TD 19W WILL TRACK WESTWARD FOR THE REMAINDER OF THE
FORECAST. THE CROSS-TRACK SPREAD AT LANDFALL BETWEEN TAU 48-72 IS
70NM, WITH NAVGEM TO THE NORTH AND THE ECMWF ENSEMBLE TO THE SOUTH.
THE INTENSITY GUIDANCE SHOWS A LARGER SPREAD, WITH PEAK
INTENSITIES AT TAU 48 BETWEEN 50-100KTS. THE JTWC GUIDANCE
INDICATES A 50 PERCENT PROBABILITY OF RAPID INTENSIFICATION BY TAU
72, BUT KEY FEATURES MAY NOT PERMIT A SIGNIFICANT RATE OF
INTENSIFICATION. THE UPPER-LEVEL ENVIRONMENT WILL REMAIN PRIMARILY
EQUATORWARD AND THE OHC IS NOT VERY HIGH NEAR THE GULF OF TONKIN.
AS THE SYSTEM APPROACHES THE SHALLOWER WATERS OF THE GULF OF
TONKIN, THE INFLUENCE OF UPWELLING MAY BECOME MORE SIGNIFICANT.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 0 - 72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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