Advisories

WDPN31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (KROVANH) 
WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.9N 129.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 108 NM EAST-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS THE
REEMERGENCE OF THE LOOSE, POORLY DEFINED LOW LEVEL CIRCULATION FROM
UNDER OBSCURING CONVECTION AND CIRRUS IN THE LAST FEW HOURS. IT
APPEARS THAT THE LOW-LEVEL CIRCULATION CENTER (LLCC) THAT HAD BEEN
PREVIOUSLY TRACKED HAS RECONSTITUTED ITSELF IN THE VICINITY OF
LOCALIZED DEEP CONVECTION EAST OF OKINAWA. THAT CONVECTION IS
DISSIPATING AND A NEW BURST OF CONVECTION IS BEGINNING TO WRAP
AROUND THE WESTERN SIDE OF THE ASSESSED CIRCULATION CENTER.
POLEWARD OUTFLOW HAS CONTINUED TO WEAKEN OVER THE PAST 6 HOURS,
THOUGH THE CHANNEL IS STILL PRESENT. UNFORTUNATELY, THERE HAVE BEEN
NO SCATTEROMETER PASSES DIRECTLY OVER TROPICAL DEPRESSION (TD) 22W
FOR MORE THAN 18 HOURS, SO IT'S DIFFICULT TO CONFIRM THE LOW-LEVEL
WIND STRUCTURE OR CHARACTERIZE ITS EVOLUTION. THE INITIAL POSITION
IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE ROTATION OBSERVED IN
ANIMATED MSI. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH LOW
CONFIDENCE, HEDGED SLIGHTLY BELOW THE CONSENSUS OF AGENCY DVORAK
FIXES AND OBJECTIVE INTENSITY ESTIMATES IN LIGHT OF THE SYSTEM'S
POOR ORGANIZATION AND DISTANCE FROM ENHANCED GRADIENT WINDS. THE
ENVIRONMENT IS CHARACTERIZED AS MARGINAL FOR FURTHER DEVELOPMENT
DUE TO LOW-MODERATE VERTICAL WIND SHEAR (VWS), WEAKENING OUTFLOW
ALOFT, AND CONTINUED DRY AIR ENTRAINMENT, DESPITE WARM SEA SURFACE
TEMPERATURES.

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

CURRENT STEERING MECHANISM: THE NORTHERN PERIPHERY OF A NEAR
EQUATORIAL RIDGE (NER) POSITIONED TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   CIMSS ADT: 35 KTS AT 052340Z
   CIMSS AIDT: 36 KTS AT 052340Z
   CIMSS D-PRINT: 28 KTS AT 060020Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE WEST

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST TRACK AS A WHOLE HAS
SHIFTED WESTWARD AS A RESULT OF THE 060000Z ANALYZED POSITION,
FOLLOWING THE REORGANIZATION OF THE LLCC.

FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 22W HAS GONE THROUGH
A REORGANIZATION PHASE OVER THE PAST 6 HOURS AND REEMERGED JUST
NORTHWEST OF MINAMI DAITOJIMA. THE TRACK IS FORECAST TO RESUME IN
AN EAST-NORTHEASTWARD DIRECTION FOR THE NEXT 24 HOURS UNDER THE
STEERING INFLUENCE OF THE NER TO THE SOUTH. AFTER TAU 24, A
POLEWARD TURN IS EXPECTED AS THE SYSTEM TRACKS ALONG THE WESTERN
PERIPHERY OF A SUBTROPICAL RIDGE (STR) POSITIONED SOUTHEAST OF
JAPAN. A NORTHEASTWARD TURN IS EXPECTED TO BEGIN AROUND TAU 60 AS
22W APPROACHES THE RIDGE AXIS. PERSISTENT LOW-MODERATE VWS AND
CONTINUED DRY AIR ENTRAINMENT ARE EXPECTED TO PREVENT ANY FURTHER
INTENSIFICATION OF 22W, INSTEAD RESULTING IN A GRADUAL WEAKENING
TREND AS IT APPROACHES SOUTHERN HONSHU. THE CIRCULATION WILL LIKELY
BECOME EXTREMELY STRETCHED AS IT INTERACTS WITH THE HOSTILE
UPPER-LEVEL WINDS AFTER TAU 60, RESULTING IN DISSIPATION BY TAU 96.
IT IS POSSIBLE THAT THE LLCC IS UNABLE TO REMAIN INTACT UNDER
UNFAVORABLE ENVIRONMENTAL CONDITIONS, IN WHICH CASE DISSIPATION
WOULD OCCUR SOONER.

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN MODERATE AGREEMENT
THROUGH TAU 48 WITH A CROSS-TRACK SPREAD OF 80 NM FOLLOWING THE
POLEWARD TURN. AFTER TAU 48, SOME TRACKERS BEGIN TO LOSE THE VORTEX
WHILE THOSE THAT MAINTAIN THE VORTEX TEND TO ACCELERATE
NORTHEASTWARD. THE JTWC TRACK FOLLOWS CLOSE TO THE MULTI-MODEL
CONSENSUS THROUGH TAU 48, THEN CLOSER TO THE GUIDANCE THAT FAVORS
THE DISSIPATION SCENARIO. ALL INTENSITY GUIDANCE REMAINS AT OR
BELOW 35 KTS, WITH THE EXCEPTION OF GFS-BASED COAMPS-TC. THE JTWC
INTENSITY FORECAST FOLLOWS CLOSE TO THE CONSENSUS MEAN THROUGH TAU
48, THEN JUST BELOW THE MEAN IN ANTICIPATION OF DISSIPATION DUE TO
THE EXPECTED UNFAVORABLE ENVIRONMENT.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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