WDIO31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 07A (SEVEN) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.9N 64.9E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 524 NM SOUTHEAST OF MASIRAH ISLAND
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
CIRA PROXY VISIBLE IMAGERY FROM MET-9 DEPICTS AN EXPOSED LOW LEVEL
CENTER (LLC) DISPLACED APPROXIMATELY 40NM TO THE SOUTHWEST OF DEEP
CONVECTION DUE TO THE PRESENCE OF STRONG (20-25 KNOT) SOUTHWESTERLY
VERTICAL WIND SHEAR. DESPITE THE OBVIOUS DECOUPLING, A 152351Z
SSMIS PASS REVEALS THE LOW LEVEL STRUCTURE REMAINS REASONABLY WELL
INTACT. THE CURRENT POSITION WAS PLACED JUST AHEAD OF AGENCY FIXES
BASED ON THE AFOREMENTIONED SSMIS DATA. THE INTENSITY WAS HELD AT 35
KNOTS GIVEN THE LOW LEVEL STRUCTURE, WHICH IS COMMENSURATE WITH
MULTI-AGENCY FINAL-T DVORAK ESTIMATES OF T2.0 TO T2.5, AS WELL AS AN 
ADT VALUE OF 34 KTS AND SATCON OF 40 KTS.

INITIAL WIND RADII BASIS: EXTRAPOLATION FROM PRIOR ASCAT DATA AND
PERSISTENCE. 

CURRENT STEERING MECHANISM: EXTENSION OF MID-LEVEL RIDGE ANCHORED
OVER CENTRAL INDIA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T2.0 - 30 KTS
   CIMSS SATCON: 40 KTS AT 152126Z
   CIMSS ADT: 34 KTS AT 152115Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: SIGNIFICANT DRY AIR OVER THE ARABIAN SEA.

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: UNFAVORABLE ENVIRONMENTAL CONDITIONS INCLUDING
PERSISTENT VERTICAL WIND SHEAR AND DRY AIR ARE EXPECTED TO CONTINUE 
ERODING THE REMAINING LLC AS IT TRACKS WESTWARD OVER COOLER (26 
DEGREE C) WATERS. THE FORECAST CALLS FOR TC 07A TO WEAKEN BELOW 
WARNING CRITERIA AT TAU 24, HOWEVER, THIS DISSIPATION COULD OCCUR 
SOONER BASED ON THE LATEST GLOBAL MODEL GUIDANCE, INCLUDING THE GFS 
AND ECMWF MODELS. AFTER DISSIPATION, REMNANTS OF TC 07A MAY CONTINUE 
TO TRACK WESTWARD TOWARDS SOCOTRA ISLAND. NO FURTHER RE-
INTENSIFICATION IS EXPECTED.  

MODEL DISCUSSION: MODELS ARE IN GOOD AGREEMENT WITH THE WESTWARD
TRACK, WITH A CONSENSUS SPREAD OF 40 NM AT TAU 24. LIKEWISE,
INTENSITY GUIDANCE AGREES ON DISSIPATION WITHIN 24 HOURS, EXCEPT
FOR COAMPS-TC, WHICH MAINTAINS A WEAK TROPICAL STORM EQUIVALENT
INTENSITY UNTIL TAU 36. 

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