WDPN31 PGTW 110300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 27W WARNING NR 03//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL DEPRESSION (TD) 27W HAS MAINTAINED INTENSITY OVER
THE PAST 12 HOURS. RECENT ANIMATED INFRARED IMAGERY INDICATED A
WEAK SYSTEM WITH LIMITED DEEP CONVECTION, WEAK BANDING AND A DEFINED
LOW-LEVEL CIRCULATION CENTER (LLCC). THE LATEST MULTISPECTRAL IMAGERY
SHOWS THAT THE LLCC MAY HAVE OPENED BACK UP INTO A MORE WAVE-LIKE
FEATURE AND SHOWED NO EVIDENCE OF A CLOSED CIRCULATION OVER THE
SOUTHERN QUADRANT E.G., NO WESTERLY LOW-LEVEL CLOUD LINES WRAPPING
INTO THE CENTER. INSTEAD DEEP CONVECTION IS FLARING IN A LINEAR
FASHION NORTHEAST TO SOUTHWEST. THE SYSTEM IS TRACKING RAPIDLY
WESTWARD AT 15-17 KNOTS. MODEL GUIDANCE HAS REMAINED LIMITED
AND MORE CONSISTENT OVER THE PAST 12 HOURS.
   B. TD 27W IS EMBEDDED WITHIN ENHANCED FLOW BETWEEN LOW-LEVEL
NORTHEASTERLIES ASSOCIATED WITH THE SUBTROPICAL RIDGE POSITIONED
NORTH AND A BROAD CYCLONIC CIRCULATION TO THE SOUTHWEST. ANIMATED
WATER VAPOR IMAGERY DEPICTS POOR OUTFLOW WITH THE SYSTEM ISOLATED
WITHIN GENERALLY DRY STABLE AIR OVER MUCH OF THE WESTERN PACIFIC.
THE CURRENT POSITION IS BASED ON VISIBLE IMAGERY AS WELL AS A
102200Z SSMIS IMAGE DEPICTING A WEAK LLCC WEST OF THE CURVED
CONVECTIVE BAND. THE CURRENT INTENSITY IS ASSESSED SLIGHTLY
HIGHER THAN DVORAK ESTIMATES OF 25 KNOTS BASED ON STRONGER WINDS
OBSERVED NORTH OF THE CENTER ENHANCED BY THE PRESSURE GRADIENT
BETWEEN THE SYSTEM AND HIGH PRESSURE NORTH.  
3. FORECAST REASONING.
   A. FORECAST TRACK HAS BEEN SHIFTED SOUTH TO REFLECT A MORE WEST-
WARD TO WEST-SOUTHWESTWARD TRACK WITH A LOWER PEAK INTENSITY OF 35
KNOTS. 
   B. TD 27W IS TRACKING ALONG SOUTHERN PERIPHERY OF THE LOW- TO
MID-LEVEL SUBTROPICAL RIDGE (STR) WITHIN AN AREA OF ENHANCED FLOW
NORTH OF A BROAD CYCLONIC CIRCULATION THEREFORE THE SYSTEM HAS BEEN
TRACKING RAPIDLY WESTWARD AND HAVING DIFFICULTY CONSOLIDATING. THE
SYSTEM IS FORECAST TO CONTINUE TRACKING GENERALLY WESTWARD AND IS
NOT EXPECTED TO INTENSIFY BEYOND A WEAK TS DUE TO THE UNFAVORABLE
OUTFLOW AND PERSISTENT NORTHEASTERLY FLOW. THE AVAILABLE MODEL
GUIDANCE HAS IMPROVED OVER THE PAST 12 HOURS AND IS IN AGREEMENT
WITH THE OFFICIAL FORECAST BUT IS LIMITED TO THE UK MET OFFICE
MODEL, WBAR, GFS AND JGSM. AVAILABLE INTENSITY GUIDANCE INDICATES
A PEAK INTENSITY OF 65-70 KNOTS BUT IS DEEMED UNRELIABLE DUE TO
THE CONTINUED MARGINAL ENVIRONMENT AND STRONG, DRIER NORTHEASTERLY
EXPECTED TO HAMPER DEVELOPMENT.  
   C. TD 27W IS FORECAST TO TRACK MORE WEST-SOUTHWESTWARD UNDER A
RENEWED NORTHEASTERLY SURGE EXPECTED TO DEVELOP. THIS SHOULD HELP
DISSIPATE THE SYSTEM OVER WATER BY TAU 120.  
FORECAST TEAM: CHARLIE//
BT
#0280
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