WDPN32 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (LEEPI) WARNING 
NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 35.8N 148.3E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 421 NM EAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 11 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE LOW LEVEL
CIRCULATION CENTER HAS BECOME FULLY EXPOSED AS THE CENTRAL DENSE
OVERCAST IS SHEARED EASTWARD AND STRIPPED OF DEEP CONVECTION. THE
MSI LOOP ALSO SHOWS COOL DRY AIR INTRUSION ALONG THE WESTERN
PERIPHERIES AS EVIDENCED BY STRATOCUMULUS CLOUD LINES WRAPPING
TOWARD THE LLC. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE EXPOSED LLCC IN THE MSI LOOP. THE INITIAL INTENSITY OF
30KTS IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON THE DVORAK
ESTIMATES FROM PGTW AND RJTD THAT REFLECTS THE SIGNIFICANT 6-HR
CONVECTIVE DETERIORATION. ANALYSIS INDICATES THE ENVIRONMENT REMAINS 
MARGINAL WITH WARM SST AND WEAK RADIAL OUTFLOW OFFSET BY HIGH VWS AND 
COOL DRY AIR INTRUSION AT THE LOW LEVELS.

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

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 35 KTS AT 052330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 30+ KTS
   SST: 27-28 CELSIUS
   OUTFLOW: WEAK RADIAL
   OTHER FACTORS: COOL DRY AIR INTRUSION NEAR THE SURFACE.

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 LEEPI WILL CONTINUE TO ACCELERATE
NORTHEASTWARD ON THE POLEWARD SIDE OF THE STEERING STR. THE
MARGINAL ENVIRONMENT WILL REDUCE THE SYSTEM TO 25KTS BY TAU 24 AND
INHIBIT ANY FURTHER INTENSIFICATION. CONCURRENTLY BY TAU 12, THE
SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AND BY TAU 36,
WILL TRANSFORM INTO A COLD CORE LOW. THERE IS ALSO A DISTINCT
POSSIBILITY THAT TD 13W WILL DISSIPATE PRIOR TO COMPLETION OF ETT.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH AN
EVEN SPREAD TO A MERE 77NM BY TAU 36, LENDING HIGH CONFIDENCE IN
THE JTWC TRACK FORECAST. GIVEN THE VARIABILITY ASSOCIATED WITH ETT
AND THE POSSIBILITY OF AN EARLY DISSIPATION, THERE IS ONLY MEDIUM
CONFIDENCE IN THE JTWC INTENSITY FORECAST. 


FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
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