Advisories

WDPN32 PGTW 060900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (KUJIRA) WARNING 
NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.0N 121.7E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 150 NM NORTH-NORTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 10 KTS

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
DEPRESSION 13W (KUJIRA) AS A POORLY CONSOLIDATED SYSTEM THAT
APPEARS TO BE MOSTLY, IF NOT ALL, CONFINED TO THE MIDLEVEL AT THIS
POINT. STRONG GRADIENT FLOW FROM THE WEST AND NORTHWEST DOMINATE
ANIMATED MSI; THE FLOW SURGES OVER LUZON AND CONVERGES ON THE
EASTERN COAST, CAUSING THE LINE OF DEEP CONVECTION. THE 060430Z
OSCAT DATA CONFIRMS WHAT IS IDENTIFIABLE IN ANIMATED IMAGERY:
STRONG STRAIGHT-LINE FLOW PRESENT ON BOTH SIDES OF LUZON.
ADDITIONALLY, SURFACE OBSERVATIONS FROM LUZON DO NOT SUPPORT THE
PRESENCE OF A SURFACE CIRCULATION, WITH APARRI REPORTING
NORTHWESTERLIES AT 12 KTS AND TUGUEGARAO (APPROXIMATELY 35 NM FROM
THE ASSESSED CENTER) REPORTING 2 KT EAST-NORTHEASTERLIES. THE
PERSISTENT MIDLEVEL TURNING IS BEGINNING TO BE SHEARED APART AND
BECOMING SIGNIFICANTLY LESS DEFINED AS IT TRACKS ACROSS LUZON AND
EMERGES OVER WATER. IT IS DIFFICULT TO DETERMINE IF THE LOW LEVEL
CENTER IS TRULY GONE WHILE THE SYSTEM REMAINS OVER LUZON, THOUGH
THE OSCAT AND SURFACE OBSERVATIONS ARE STRONG INDICATORS.
ENVIRONMENTAL ANALYSIS REVEALS A HIGHLY UNFAVORABLE ENVIRONMENT,
CHARACTERIZED BY MOUNTAINOUS TERRAIN INTERACTION OVER LUZON,
MODERATE TO HIGH (20-25 KTS) VERTICAL WIND SHEAR (VWS), AND STRONG
WESTERLY GRADIENT FLOW ENHANCED BY INFLOW TO TYPHOON 12W (DOLPHIN).
THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON THE
PGTW POSITION FIX AND MIDLEVEL ROTATION. THE INITIAL INTENSITY OF
25 KTS IS ASSESSED WITH LOW CONFIDENCE BASED ON A WEAKENING TREND
OVER LAND AND THE WEAK SURFACE OBSERVATIONS.

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

CURRENT STEERING MECHANISM: EXTENSIVE LOWER-LEVEL WESTERLY
MONSOONAL SURGE FLOW


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   KNES: T1.5 - 25 KTS
   CIMSS D-MINT: 30 KTS AT 060521Z
   CIMSS D-PRINT: 28 KTS AT 060610Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 20-25 KTS
   SST: OVER LAND
   OUTFLOW: WEAK EQUATORWARD
   OTHER FACTORS: TERRAIN INTERACTION WHILE POSITIONED OVER LUZON

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: LOW
   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 13W (KUJIRA) WILL CONTINUE TRACKING OVER
LUZON WHILE REMAINING UNDER THE STEERING INFLUENCE OF THE WESTERLY
SURGE, EMERGING OVER WATER WITHIN THE NEXT FEW HOURS. ONCE OVER
WATER, THE SHALLOW REMNANTS OF 13W WILL BE CARRIED NORTHEASTWARD AS
IT GETS ABSORBED INTO TY 12W'S INFLOW.  13W IS EXPECTED TO BE FULLY
DISSIPATED NO LATER THAN TAU 24; HOWEVER, THE SURFACE CIRCULATION
HIGHLY LIKELY DISSIPATED OVER LUZON AND THE REMNANT MIDLEVEL
CIRCULATION WILL LIKELY BE GONE WITHIN 12 HOURS. WIND SPEEDS ARE
EXPECTED TO REMAIN ELEVATED THROUGHOUT THE FORECAST PERIOD DUE TO
THE ACCELERATED WESTERLIES.

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 24, SUPPORTING THE JTWC TRACK FORECAST WITH
HIGH CONFIDENCE. DETERMINISTIC GFS AND ECMWF DEPICT 13W REEMERGING
OVER THE PHILIPPINE SEA AS AN OPEN TROUGH RATHER THAN A CLOSED
CIRCULATION, SUPPORTING DISSIPATION PRIOR TO TAU 24. RELIABLE
INTENSITY AIDS ARE IN STRONG AGREEMENT THAT 13W WILL NOT INTENSIFY
WHEN REEMERGING OVER WATER, AND DEPICT THE STRONG WESTERLIES
DRIVING THE INCREASED WIND SPEEDS VICE THE CIRCULATION ITSELF. AS A
RESULT, THE JTWC INTENSITY FORECAST IS ASSESSED WITH HIGH
CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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