WDIO31 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (ASNA) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.9N 62.6E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 260 NM NORTHEAST OF MASIRAH ISLAND
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 02A (ASNA) WITH A DEGRADED APPEARANCE OVER THE PAST 6 HOURS
AS DRY AIR HAS STARTED TO QUICKLY WEAKEN THE SYSTEM. THE CONVECTION
THAT WAS FORMING NEAR THE CENTER IS NOW MINIMAL AND IS BEING BLOWN
OFF TO THE NORTHWEST AS SOUTHEASTERLY SHEAR ACTS ON THE SYSTEM. THE
LOW-LEVEL CIRCULATION CENTER (LLCC) IS ALMOST COMPLETELY EXPOSED
NOW AS THE CONVECTION CONTINUES TO DISAPPEAR. ENVIRONMENTAL
ANALYSIS INDICATES THAT 02A IS IN AN UNFAVORABLE ENVIRONMENT. THE
MODERATE EQUATORWARD OUTFLOW ALOFT, MODERATE VERTICAL WIND SHEAR,
AND RELATIVELY WARM SEA SURFACE TEMPERATURES ARE GREATLY OFFSET BY 
SIGNIFICANT DRY AIR ENTRAINMENT. THE INITIAL POSITION IS PLACED WITH 
MEDIUM CONFIDENCE BASED ON THE ANIMATED EIR IMAGERY. THE INITIAL 
INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE 
OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHEASTERN PERIPHERY OF A
DEEP-LAYERED RIDGE TO THE NORTHWEST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T2.5 - 35 KTS
   CIMSS SATCON: 43 KTS AT 312330Z
   CIMSS ADT: 39 KTS AT 010000Z
   CIMSS DPRINT: 39 KTS AT 010000Z
   CIMSS DMINT: 36 KTS AT 312356Z 

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: SIGNIFICANT DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: 02A IS FORECAST TO CONTINUE TRACKING
SOUTHWESTWARD ALONG THE SOUTHEASTERN PERIPHERY OF THE RIDGING TO
ITS NORTHWEST FOR THE REMAINDER OF THE FORECAST PERIOD. DRY AIR HAS
ALREADY STARTED TO ERODE THE SYSTEM ALONG WITH THE MODERATE
VERTICAL WIND SHEAR. AS THE CORE OF 02A CONTINUES TO DRY OUT, IT IS
EXPECTED TO WEAKEN THROUGH TAU 24 WHERE IT DROPS TO BELOW TROPICAL
STORM STRENGTH NORTHEAST OF MASIRAH ISLAND. 

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL
GUIDANCE IS IN VERY GOOD AGREEMENT WITH A CROSS-TRACK SPREAD OF
JUST 30 NM IN CONSENSUS MEMBERS (NOT ACCOUNTING FOR NAVGEM). THIS 
LENDS HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. THE INTENSITY 
GUIDANCE IS ALSO IN VERY GOOD AGREEMENT WITH THE VAST MAJORITY OF 
MODELS DEPICTING THE WEAKENING TREND THROUGH TAU 24. AS A RESULT, THE 
JTWC INTENSITY FORECAST IS ALSO PLACED WITH HIGH CONFIDENCE. 

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