WDPN31 PGTW 060900 AMD
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W (CONSON) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 10.8N 126.9E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 414 NM EAST-SOUTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A SYSTEM
WHICH HAS SIGNIFICANTLY IMPROVED IN STRUCTURE OVER THE PAST 12
HOURS, WITH SUSTAINED DEEP CONVECTION OVER THE CENTER. THE INITIAL 
POSITION IS BASED ON AN EYE-LIKE FEATURE THAT WAS PRESENT IN VISIBLE 
IMAGERY AROUND 0500Z. THE INITIAL INTENSITY IS BASED ON A 060442Z 
AMSR2 WINDSPEED PRODUCT SHOWING 50 KT WIND IN THE EASTERN PORTION OF 
THE CIRCULATION WITH POSSIBLE 55-65 KT GUSTS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 32 KTS AT 060540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: CURRENT INTENSITY AND FORECAST
INTENSITY HAVE BEEN SIGNIFICANTLY INCREASED FROM PREVIOUS WARNING.

FORECAST DISCUSSION: TS 18W IS FORECAST TO CONTINUE NORTHWESTWARD
ON ITS CURRENT TRACK, SKIRTING ALONG THE EASTERN PORTION OF THE
PHILIPPINES AND THEN EVENTUALLY CROSSING LUZON 39 NM NORTH OF
MANILA AROUND TAU 72. AFTERWARDS, IT WILL REEMERGE OVER WATER,
HEADING WEST-NORTHWESTWARD TOWARDS HAINAN. THE SYSTEM IS EXPECTED
TO REACH AN INTENSITY OF 65 KTS BY TAU 24, AT WHICH TIME LAND
INTERACTION WILL SLOW INTENSIFICATION AND EVENTUALLY DECREASE TO 55
KTS AS IT CROSSES LUZON. BY TAU 120, WARM SEA SURFACE TEMPERATURES
AND LOW VERTICAL WIND SHEAR WILL ALLOW TS 18W TO REACH AN INTENSITY
OF 70 KTS. OF NOTE, TD 19W IS CURRENTLY 700NM EAST-NORTHEASTWARD OF
TS 18W. THIS DISTANCE IS ON THE HIGHER THRESHOLD OF POSSIBLE BINARY
INTERACTION BETWEEN THE SYSTEMS AND THE CURRENT FORECAST DOES NOT
PREDICT ANY INTERACTION, AS THE CURRENT FORECAST TRACKS MAINTAIN
ABOUT 700 NM SEPARATION UP TO TAU 72, AT WHICH POINT THE DISTANCE
BEGINS TO INCREASE.

MODEL DISCUSSION: NUMERICAL MODELS ARE GENERALLY IN GOOD AGREEMENT
IN REGARDS TO THE TRACK FORECAST, IN WHICH ALL MODELS SHOW A 
NORTHWESTWARD TRACK UP TO TAU 72, AND THEN A WEST-NORTHWESTWARD
TRACK AFTERWARDS. INTENSITY GUIDANCE IS IN AGREEMENT AS FAR AS THE
INTENSITY TREND, WITH ALL MODELS PREDICTING CONTINUED
INTENSIFICATION, FOLLOWED BY A WEAKENING PERIOD AROUND TAU 72
BEFORE RESUMING STEADY INTENSIFICATION AFTERWARDS. THE OUTLIER IS
GFS WHICH SHOWS LITTLE TO NO INTENSIFICATION IN THE NEAR TERM. THE
FORECAST INTENSITY IS THEREFORE PLACED SLIGHTLY HIGHER THAN
CONSENSUS.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW

JUSTIFICATION FOR AMENDMENT: AMENDED FORECAST INTENSITY FROM 
PREVIOUS WARNING.//
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