WDXS32 PGTW 060900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 10S (CLIFF) WARNING 
NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.5S 80.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 1023 NM SOUTH-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS LOW-LEVEL
CLOUD LINES WRAPPING TIGHTLY INTO AN EXPOSED LOW-LEVEL CIRCULATION
CENTER, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. A
052324Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS ISOLATED, DISORGANIZED
DEEP CONVECTION SHEARED OVER THE SOUTHERN QUADRANT. ENVIRONMENTAL
CONDITIONS REMAIN UNFAVORABLE WITH NORTHERLY VERTICAL WIND SHEAR,
EXTENSIVE DRY AIR ENTRAINMENT AND MARGINAL SEA SURFACE
TEMPERATURES. A 060404Z ASCAT-B IMAGE SHOWS 30-35 KNOT WINDS OVER
THE SOUTHERN SEMICIRCLE, WHICH SUPPORTS THE INITIAL INTENSITY OF 35
KTS WITH HIGH CONFIDENCE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF LOW TO MID-LEVEL
SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   CIMSS ADT: 35 KTS AT 060315Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR MASS EXCEPT FOR SHALLOW LAYER OF MOISTURE
IN THE LOWER LEVELS 

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 10S IS SITUATED IN AN UNFAVORABLE, VERY DRY
ENVIRONMENT WITH EXTENSIVE STRATOCUMULUS, INDICATIVE OF A COOLER,
MORE STABLE AIRMASS, OVER THE SOUTHERN SEMICIRCLE ADVECTING AROUND
THE WESTERN SEMICIRCLE. ADDITIONALLY, PERSISTENT MODERATE TO STRONG
(20-25 KNOTS) VERTICAL WIND SHEAR AND MODERATE POLEWARD VENTING IS
LIMITING DEEP CONVECTION TO THE SOUTHERN QUADRANT ONLY. ALTHOUGH
THERE ARE GRADIENT-ENHANCED GALE FORCE WINDS OVER THE SOUTHERN
SEMICIRCLE, NUMERICAL MODEL GUIDANCE INDICATES A GRADUAL WEAKENING
OF THESE WINDS OVER THE NEXT 24 HOURS THUS THE SYSTEM IS FORECAST
TO DISSIPATE NO LATER THAN TAU 24 AS IT TRACKS WEST-
SOUTHWESTWARD.     

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, WHICH TRACKS
DIRECTLY INTO THE STRONG HIGH TO THE SOUTH, MODEL TRACKERS ARE IN
TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK.
INTENSITY GUIDANCE ALSO SUPPORTS THE JTWC INTENSITY FORECAST WITH
THE BULK OF THE GUIDANCE SHOWING A STEADY WEAKENING TREND.
 
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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