WDPN31 PGTW 300300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 11W (ELEVEN) WARNING 
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.9N 154.7E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 583 NM EAST OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION, AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
CONSOLIDATING REGION OF PERSISTENT DEEP CONVECTION THAT IS FULLY
OBSCURING THE LOW LEVEL CIRCULATION CENTER BENEATH. A 282011Z SUITE
OF SSMIS MICROWAVE IMAGERY INDICATES BANDS OF DEEP CONVECTION TO
THE EAST AND SOUTH WRAPPING INTO A BROAD AND SLIGHTLY ELONGATED
CIRCULATION CENTER. THE CROWN JEWEL OF RECENT DATA IS A BULLSEYE
292330Z ASCAT-C SCATTEROMETRY PASS WHICH SHOWS AN EAST-WEST
ELONGATED CIRCULATION OF 25KTS WITH SEVERAL PATCHES OF 30KT WINDS
WITHIN THE DEEPEST CONVECTION. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON MSI, SSMIS AND SCATTEROMETRY DATA. THE
INITIAL INTENSITY OF 25 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED
ON RECENT SCATTEROMETRY DATA.

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

CURRENT STEERING MECHANISM: ONGOING TRANSITION FROM A
NEAREQUATORIAL RIDGE (NER) TO THE SOUTH, TO A SUBTROPICAL RIDGE
(STR) TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.0 - 25 KTS
   RJTD: T1.0 - 25 KTS
   KNES: T1.5 - 25 KTS
   CIMSS ADT: 28 KTS AT 292358Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: THE FORECAST TRACK FOR TD 11W IS INITIALLY
STRAIGHTFORWARD, AS WE SPEAK THE SYSTEM IS TRANSITIONING STEERING
FLOW TO A STR POSITIONED TO THE NORTHEAST. THROUGH TAU 48, 11W WILL
TRANSIT GENERALLY NORTHWARD AND EVENTUALLY NORTH-NORTHWESTWARD.
BEYOND TAU 48, THE EXISTENCE AND STRENGTH OF TWO PARTICULAR
ATMOSPHERIC BODIES WILL DETERMINE THE EXTENDED TRACK OF 11W. THE
FIRST AND MORE GENERIC IS THE ORIENTATION AND STRENGTH OF THE
STEERING RIDGE TO THE NORTHEAST. THE PREPONDERANCE OF AVAILABLE
GUIDANCE INDICATES THE STR WILL PERSIST AND FORCE THE SYSTEM
WESTWARD. THE SECOND AND MORE COMPLICATED FACTOR IS THE ANTICIPATED
FORMATION OF YET ANOTHER TROPICAL CYCLONE IN THE PHILIPPINE SEA
(PFA P72W). IF THIS SYSTEM DOES DEVELOP AND INTENSIFY AS GFS IS
ANTICIPATING, AFTER TAU 72, 11W AND THIS NEW SYSTEM WILL CLOSE
WITHIN 700NM AND BEGIN A BINARY INTERACTION. BY TAU 96 AND THROUGH
THE FORECAST PERIOD, THE TWO SYSTEMS CONTINUE THEIR INTERACTION AND
POTENTIALLY MERGE WITH ONE ANOTHER IN A PROCESS KNOWN AS THE
FUJIWHARA EFFECT. SUFFICE TO SAY, BINARY INTERACTION IS A HIGHLY
COMPLEX PHENOMENA TO FORECAST AND CAN LEAD TO ERRATIC AND SOMETIMES
UNPREDICTABLE OUTCOMES. IN TERMS OF INTENSITY, 11W IS FORECAST TO
QUICKLY INTENSIFY TO 50KTS BY TAU 24, FUELED BY WARM WATERS AND
ROBUST POLEWARD OUTFLOW, DUE TO A TROPICAL UPPER TROPOSPHERIC
TROUGH (TUTT) CENTERED TO THE NORTHWEST. AS THE SYSTEM MOVES TO THE
EAST OF THE TUTT HOWEVER, INCREASED SHEAR VALUES AND SUBSIDENCE
WILL BLUNT THE SYSTEMS SHARP INTENSIFICATION TREND. A BRIEF PERIOD
OF INTENSIFICATION IS ONCE AGAIN POSSIBLE NEAR TAU 72, AS SHEAR
VALUES FALL AND OUTFLOW IMPROVES, LEADING TO A PEAK INTENSITY NEAR
60KTS. AFTER TAU 72, AS PREVIOUSLY MENTIONED, BINARY INTERACTION, OR
LACK THEREOF WILL DOMINATE THE RELIABILITY BOTH THE TRACK AND
INTENSITY FORECASTS, THOUGH JTWC IS ANTICIPATING GRADUAL WEAKENING
AS THE TWO SYSTEMS CLOSE WITH ONE ANOTHER THROUGH THE FORECAST
PERIOD.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH
TAU 72 WITH ALL MEMBERS CLOSELY FOLLOWING THE MULTI-MODEL
CONSENSUS. AFTER TAU 72, THE BULK OF THE MODEL GUIDANCE INDICATES A
WESTWARD TRACK THROUGH THE FORECAST PERIOD WHILE NVGM AND COAMPS-TC
(NVGM) INDICATE A POLEWARD RECURVE. FOR THESE REASONS THE JTWC
FORECAST TRACK IS PLACED INITIALLY WITH MEDIUM CONFIDENCE AND WITH
LOW CONFIDENCE THEREAFTER. RELIABLE MODEL INTENSITY GUIDANCE IS IN
FAIR AGREEMENT WITH A BULK OF THE GUIDANCE FOLLOWING THE JTWC
INTENSITY FORECAST TREND THROUGH TAU 36. AFTER TAU 36, MEMBER
GUIDANCE DIVERGES AS VARIOUS MODELS ATTEMPT TO RESOLVE THE
AFOREMENTIONED CONFOUNDING VARIABLES IN THE EXTENDED TRACK. FOR
THESE REASON, THE JTWC INTENSITY FORECAST IS PLACED INITIALLY WITH
MEDIUM CONFIDENCE AND WITH LOW CONFIDENCE THEREAFTER.

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