WDPN31 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 02W (TWO) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 4.2N 147.1E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 572 NM SOUTH-SOUTHEAST OF NAVSTA GUAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
CONSOLIDATING SYSTEM WITH IMPROVED CONVECTIVE BANDING OVER THE
NORTHERN AND WESTERN SEMICIRCLES. UNFORTUNATELY, THERE IS NO USEFUL
ASCAT OR MICROWAVE IMAGERY OVER THE PAST SIX HOURS, HOWEVER, THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A TIGHT
GROUPING OF AGENCY POSITION FIXES. ENVIRONMENTAL CONDITIONS REMAIN
FAVORABLE WITH MODERATE WESTWARD OUTFLOW AND LOW VERTICAL WIND
SHEAR (VWS) AS WELL AS WARM SST VALUES AND HIGH OCEAN HEAT CONTENT.
THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE PGTW AND KNES DVORAK ESTIMATES. THE 071200Z SOUNDINGS
FROM BOTH CHUUK AND GUAM INTERNATIONAL AIRPORT INDICATE DEEP
EASTERLY FLOW REFLECTING THE STRONG EAST-WEST ORIENTED SUBTROPICAL
RIDGE POSITIONED TO THE NORTH.

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

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 33 KTS AT 071140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 02W IS FORECAST TO TRACK WEST-NORTHWESTWARD
THEN NORTHWESTWARD ALONG THE SOUTHERN AND SOUTHWESTERN PERIPHERIES
OF THE STR THROUGH TAU 96. AFTER TAU 96, TD 02W WILL SLOW SLIGHTLY
AND TURN NORTH-NORTHWESTWARD AS IT APPROACHES A LARGE BREAK IN THE
STR POSITIONED SOUTH AND SOUTHEAST OF OKINAWA. AS MENTIONED
PREVIOUSLY, THE LOW- TO MID-LEVEL STR IS CURRENTLY STRONG AND IS
ORIENTED EAST-WEST SUPPORTING THE WEST-NORTHWESTWARD TRACK IN THE
EARLY PART OF THE FORECAST. TD 02W WILL INTENSIFY SLOWLY THROUGH
TAU 36 AS IT CONSOLIDATES UNDER GENERALLY FAVORABLE CONDITIONS BUT
IS FORECAST TO INTENSIFY AT A STEEPER RATE AFTER TAU 36 AS POLEWARD
OUTFLOW IMPROVES. THE PEAK INTENSITY OF 100 KNOTS IS EXPECTED NEAR
TAU 120.

MODEL DISCUSSION: ALTHOUGH GFS AND THE GFS ENSEMBLE (GEFS) REMAIN 
OUTLIERS ON THE EASTERN SIDE OF THE AIDS ENVELOPE, NUMERICAL MODEL 
GUIDANCE HAS IMPROVED AND IS IN CLOSER AGREEMENT THROUGH TAU 72 WITH A 
200NM SPREAD IN SOLUTIONS AT TAU 72. GFS HAS SHIFTED FURTHER WEST AWAY 
FROM GUAM SINCE THE PREVIOUS JTWC FORECAST BUT CONTINUES TO SHOW A 
BRIEF NORTHWARD TRACK THROUGH TAU 24 BEFORE TURNING NORTHWESTWARD. THIS 
NORTHWARD KINK IN THE TRACK HAS GRADUALLY BECOME LESS PRONOUNCED AND 
SHORTER IN DURATION OVER SUCCESSIVE MODEL RUNS. THE 070600Z ECMWF 
ENSEMBLE STRIKE PROBABILITY PRODUCT INDICATES A NARROW CONE OF 60-70 
PERCENT STRIKE PROBABILITY WEST OF 140E THROUGH TAU 96, WHICH SUPPORTS 
THE JTWC FORECAST TRACK. THE COAMPS-TC ENSEMBLE AND UK MET ENSEMBLE 
(MOGREPS) ALSO SHOW A SIMILAR GROUPING OF SOLUTIONS WEST OF 140E. THE 
GFS ENSEMBLE IS IN TIGHTER AGREEMENT AND SHOWS THE BULK OF SOLUTIONS 
WEST OF 142E. AFTER TAU 72, MODEL GUIDANCE DIVERGES SIGNIFICANTLY WITH 
GFS RECURVING THE SYSTEM NORTH-NORTHEASTWARD WHILE THE REMAINDER OF THE 
MODEL TRACKERS INDICATE A NORTHWESTWARD TO NORTHWARD TRAJECTORY. THE 
GFS SOLUTION STILL APPEARS A BIT AGGRESSIVE CONSIDERING THAT GLOBAL 
MODELS INDICATE A BROAD MIDLATITUDE RIDGE PERSISTING SOUTH OF JAPAN, 
WHICH WILL STRENGTHEN THE EXISTING STR. ADDITIONALLY, THERE ARE NO 
DYNAMIC SHORTWAVE TROUGHS SUFFICIENT TO WEAKEN THE STR THROUGH TAU 120. 
ADDITIONALLY, GFS CONTINUES TO RAPIDLY DEVELOP ANOTHER TROPICAL CYCLONE 
EAST OF THE PHILIPPINES (900-1000NM SEPARATION DISTANCE) IN THE NEXT 
TWO DAYS, WHICH INTERACTS WITH AND SLINGS 02W DIRECTLY INTO AND THROUGH 
THE STR WITH NO EVIDENCE OF ANY DYNAMIC SHORTWAVE TROUGHS THAT COULD 
POSSIBLY WEAKEN THE STR. BOTTOMLINE: THERE ARE CONCERNING ISSUES WITH 
GFS WITHIN THE SYNOPTIC STEERING ENVIRONMENT THAT ARE ODD AND UNLIKELY,
THEREFORE, THE JTWC FORECAST TRACK REMAINS POSITIONED NEAR THE JTWC
MULTI-MODEL CONSENSUS WITH THE BULK OF THE DETERMINISTIC AND 
PROBABILISTIC GUIDANCE.          

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN