Advisories

WDPN31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (KROVANH) 
WARNING NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.6N 132.9E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 364 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 19 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A MOSTLY
EXPOSED LOW-LEVEL CIRCULATION CENTER WITH MORE PERSISTENT
CONVECTION IN THE NORTHWEST QUADRANT OF TROPICAL DEPRESSION (TD)
22W AS IT SLOWLY CONSOLIDATES. THE LLCC STILL APPEARS TO BE
ELONGATED ALONG A GENERALLY NORTHWEST-SOUTHEAST AXIS AND HAS
SEPARATED ITSELF FROM THE ENHANCED SOUTHWEST MONSOON FLOW TO THE
SOUTH.  ANIMATED WATER VAPOR IMAGERY STILL SHOWS DRY AIR WRAPPING
AROUND THE SOUTHERN PERIPHERY WITH WEAK PENETRATION INTO THE CORE,
WHICH MAY CONTINUE TO INHIBIT CONSOLIDATION. 012032Z GMI 37 AND 89
GHZ MICROWAVE IMAGERY CONFIRMED THE POOR STRUCTURAL ORGANIZATION
AND LACK OF DEEP CONVECTION ASSOCIATED WITH THE DRY AIR. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MOSTLY
EXPOSED LLCC. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON T2.0 AGENCY DVORAK FIXES AND IN LIGHT OF
THE SEPARATION OF THE LLCC FROM ENHANCED SOUTHWESTERLY FLOW TO THE
SOUTH. THE ENVIRONMENT IS CHARACTERIZED AS MARGINALLY FAVORABLE,
WITH LOW VERTICAL WIND SHEAR (VWS), WARM SEA SURFACE TEMPERATURES,
AND MODERATE EQUATORWARD OUTFLOW ALOFT, AND WEAK DRY AIR
ENTRAINMENT.

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

CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A SUBTROPICAL
RIDGE (STR) CENTERED TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 32 KTS AT 020010Z
   CIMSS AIDT: 34 KTS AT 020010Z
   CIMSS D-MINT: 31 KTS AT 012034Z
   CIMSS D-PRINT: 30 KTS AT 020000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE WEST

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 22W HAS STARTED ON A NORTHWESTWARD TRACK
OVER THE PAST FEW HOURS AS IT SLOWLY CONSOLIDATES AND COMES UNDER
THE STEERING INFLUENCE OF THE STR TO THE NORTHEAST. THE
NORTHWESTWARD TRACK IS EXPECTED TO CONTINUE AS THE SYSTEM
ACCELERATES OVER THE NEXT 36 HOURS TOWARD THE RYUKYU ISLANDS. AFTER
TAU 36, THE STEERING STR IS EXPECTED TO BE WEAKENED BY A PASSING
MIDLATITUDE TROUGH AND LEAVE 22W IN AN UNCERTAIN AND WEAK STEERING
ENVIRONMENT. THE SYSTEM IS EXPECTED TO REMAIN LARGELY
QUASI-STATIONARY IN THE VICINITY OF THE RYUKU ISLANDS BETWEEN TAU
39-96, DURING WHICH TIME THERE IS A HIGH DEGREE OF UNCERTAINTY IN
ITS MOTION. BY TAU 120 THE SYSTEM IS EXPECTED TO HAVE MADE A
GENERALLY SOUTHEASTWARD SHIFT AS A RESULT OF ITS TIME IN THE WEAK
STEERING ENVIRONMENT. IN REGARD TO INTENSITY, THE SLOW
CONSOLIDATION IS EXPECTED TO CONTINUE AND THE SYSTEM IS EXPECTED TO
REMAIN VERY BROAD AND POORLY ORGANIZED, RESULTING IN VERY GRADUAL
INTENSIFICATION THROUGH TAU 60. AFTER TAU 60, INCREASING VWS WILL
CONTRIBUTE TO THE GRADUAL WEAKENING TREND. 

MODEL DISCUSSION: MODEL TRACK GUIDANCE HAS COME INTO SLIGHTLY
BETTER AGREEMENT DURING THE FIRST 36 HOURS OF THE FORECAST. AFTER
TAU 36 THERE IS VERY POOR AGREEMENT THROUGHOUT THE END OF THE
FORECAST PERIOD AS A RESULT OF THE AMBIGUOUS STEERING ENVIRONMENT
AND BROAD NATURE OF THE VORTEX. EVENTUALLY, NEARLY ALL MODELS
SUGGEST THE SYSTEM WILL TURN AROUND AND GAIN A SOUTHEASTWARD TRACK,
BUT WITH NO CONSENSUS ON THE TIMING AND LOCATION. THE JTWC TRACK
FORECAST ATTEMPTS TO SYNTHESIZE A CONSENSUS SOLUTION FROM THE
VARIED CONFIDENCE BUT WITH LOW CONFIDENCE THROUGHOUT THE FORECAST
PERIOD. INTENSITY GUIDANCE GENERALLY AGREES ABOUT THE GRADUAL
INCREASE IN INTENSITY FOLLOWED BY GRADUAL WEAKENING, HOWEVER, THE
RATE OF CONSOLIDATION IN THE NEAR TERM AND UNCERTAINTY ABOUT THE
TRACK IN THE LONGER TERM STILL LEND LOW CONFIDENCE TO THE JTWC
INTENSITY FORECAST. 

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