Advisories

WDPN32 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (KUJIRA) WARNING 
NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.4N 120.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 169 NM NORTH OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 06 KTS

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL DEPRESSION (TD) 13W HAS LIKELY MADE LANDFALL OVER THE
WESTERN COAST OF LUZON. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS DISORGANIZED CONVECTIVE BANDING THAT IS OBSCURING A
WEAK, COMPACT LOW-LEVEL CIRCULATION CENTER (LLCC). WHILE THE SYSTEM
IS IN AN AREA OF MODERATE VERTICAL WIND SHEAR (VWS) AND MODEST
DIVERGENCE ALOFT, THE INTERACTION WITH RUGGED TERRAIN IS THE
PREDOMINANTLY AND HIGHLY UNFAVORABLE FACTOR DRIVING ITS STRUCTURE.
THE INITIAL POSITION IS ASSESSED WITH LOW CONFIDENCE. THE INITIAL
INTENSITY HAS BEEN LOWERED TO 30 KTS WITH MEDIUM CONFIDENCE BASED
ON THE STANDARD DECAY RATE OVER LAND. IT IS UNCLEAR IF THE LLCC HAS
REMAINED INTACT THROUGH THE LAND INTERACTION.

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

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   RJTD: T1.5 - 25 KTS
   CIMSS D-MINT: 38 KTS AT 052332Z
   CIMSS D-PRINT: 35 KTS AT 060010Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: LAND INTERACTION

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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 13W WILL BE CARRIED EAST-NORTHEASTWARD BY
DEEP-LAYER WESTERLIES EXTENDING FROM THE SURFACE TO 400 MB. WHAT
REMAINS OF THE SYSTEM WILL EMERGE OVER THE EASTERN COAST OF LUZON
AND THE PHILIPPINE SEA WITHIN THE NEXT 12 HOURS, WITH THIS MOTION
CONTINUING UNTIL COMPLETE DISSIPATION. IT IS QUITE POSSIBLE THAT
THE CIRCULATION WILL NOT SURVIVE ITS JOURNEY OVER THE MOUNTAINOUS
TERRAIN OF NORTHERN LUZON. IN FACT, MODELS GENERALLY SUPPORT THIS
SCENARIO, DEPICTING AN OPEN TROUGH EMERGING FROM THE EASTERN COAST
RATHER THAN A CLOSED CIRCULATION. THE ENVIRONMENT WILL BE
UNFAVORABLE, CHARACTERIZED BY WARM SEA SURFACE TEMPERATURE (SST)
STRONGLY OFFSET BY MODERATE TO HIGH VWS. THE 25-KT TROUGH WILL
GRADUALLY BROADEN AND BECOME ABSORBED BY THE LARGE CIRCULATION OF
TYPHOON 12W TO THE NORTH. THE FORECAST GENEROUSLY MAINTAINS THE
SYSTEM FOR 48 HOURS BEFORE DEPICTING FULL DISSIPATION. IT IS
POSSIBLE THAT SUBSEQUENT FORECASTS MAY BE CUT SHORT IF NO EVIDENCE
OF A CLOSED CIRCULATION CAN BE FOUND WHEN IT RE-EMERGES OVER WATER.

MODEL DISCUSSION: THE MODEL TRACKERS ARE IN GOOD AGREEMENT IN AN
EASTWARD TO EAST-NORTHEASTWARD MOTION THROUGH TAU 36. THE ECMWF
SOLUTION BOUNDS THE EQUATORWARD SIDE OF THE UNCERTAINTY ENVELOPE,
WHILE THE REMAINING MODELS ARE TIGHTLY CLUSTERED. THE JTWC TRACK
FORECAST IS POSITIONED NEAR THE CONSENSUS WITH HIGH CONFIDENCE. THE
JTWC INTENSITY FORECAST DEPICTS CONTINUED WEAKENING OVER THE NEXT
12 HOURS DUE TO ONGOING LAND INTERACTION. THE RELIABLE INTENSITY
AIDS ARE FLAT, SHOWING MINIMAL STRENGTHENING OR WEAKENING, LARGELY
BECAUSE THE SYSTEM WILL REMAIN DEEPLY EMBEDDED WITHIN THE 25-30 KT
SOUTHWESTERLY FLOW. DEGENERATION INTO A TROUGH WITH 25 KT WINDS
CONFINED TO THE SOUTHERN PERIPHERY IS PREDICTED NO LATER THAN TAU
36.

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