Tropical Storm FAXAI Advisory nie., 01.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FOURTEEN) WARNING
NR 02//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 14W (FOURTEEN), LOCATED APPROXIMATELY
214 NM SOUTH-SOUTHEAST OF WAKE ISLAND, HAS TRACKED WEST-NORTHWESTWARD AT
15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A COMPACT, SHEARED SYSTEM WITH A NEARLY FULLY EXPOSED LLCC,
DISPLACED TO THE NORTHWEST OF FLARING DEEP CONVECTION. THE INITIAL POSITION
WAS RELOCATED WITH THIS WARNING BASED ON THE EMERGENCE OF THE CLEARLY
DEFINED LLCC, AND THE BEST TRACK WAS ADJUSTED TO REFLECT THIS MOVEMENT.
WITH THE LLCC NOW EXPOSED, AND COMBINED WITH AN ASSESSMENT OF A 012219Z
AMSU-B 89 GHZ MICROWAVE PASS, CONFIDENCE IN THE INITIAL POSITION HAS
IMPROVED SIGNIFICANTLY. THE AFOREMENTIONED MICROWAVE PASS SHOWED A VERY SMALL
AMOUNT OF DEEP CONVECTION TO THE SOUTH-SOUTHEAST OF THE LLCC, WHICH SUPPORTS
THE DECOUPLING OF THE LLCC FROM THE CONVECTIVE CORE. THE INITIAL INTENSITY OF
30 KNOTS IS ASSESSED WITH FAIR CONFIDENCE BASED ON DVORAK CURRENT INTENSITY
ESTIMATES OF T2.0 (30 KNOTS) FROM KNES, T1.5 (25 KNOTS) FROM PGTW, AUTOMATED
ESTIMATES OF T1.9 (29 KNOTS) AND A SATELLITE CONSENSUS ESTIMATE OF 32 KNOTS).
ENVIRONMENTAL ANALYSIS REVEALS THE SYSTEM LIES IN A FAVORABLE AREA,
WITH LOW (5-10 KNOTS) VWS, MODERATE TO STRONG POLEWARD OUTFLOW AND WARM SSTS
(28-30C).
TD 14W IS CURRENTLY TRACKING WEST-NORTHWESTWARD ALONG THE SOUTHERN
PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE. THE INITIAL POSITION HAS BEEN RELOCATED
 SINCE THE PREVIOUS WARNING DUE TO THE EMERGENCE OF THE LLLC AWAY FROM
THE CONVECTIVE SIGNATURE BUT THIS HAS NOT CHANGED THE OVERALL FORECAST
 PHILOSOPHY.
   B. TD 14W WILL TRACK GENERALLY NORTHWESTWARD THROUGH TAU 72 UNDER
THE STEERING INFLUENCE OF A DEEP-LAYER STR ANCHORED IN PLACE TO THE
NORTH. A VERY SMALL UPPER-LEVEL ANTICYCLONE APPEARS TO HAVE DEVELOPED
JUST NORTH OF TD 14W AND LED TO THE NORTHERLY SHEAR CURRENTLY AFFECTING
THE SYSTEM. HOWEVER, OVER THE NEXT 12-24 HOURS, THE ANTICYCLONE
WILL MOVE TO THE EAST, ALLOWING THE SYSTEM TO TAP INTO THE DIFFLUENT
 POLEWARD OUTFLOW ASSOCIATED WITH A TUTT CELL NORTHWEST OF THE SYSTEM.
ONCE THIS OCCURS, EXPECT TD 14W TO INTENSIFY THROUGH TAU 36 TO 40 KNOTS.
AT THIS POINT TD 14W WILL MOVE INTO A LESS FAVORABLE POSITION IN RELATION
TO THE TUTT CELL LEADING TO A DECREASE IN OUTFLOW AND A LEVELING OFF OF
INTENSITY THROUGH TAU 48. THEREAFTER AND TD 14W WILL AGAIN SLOWLY INTENSIFY
THROUGH TAU 72 AS THE TUTT CELL BEGINS TO MOVE TO THE SOUTHWEST OF TD 14W,
PLACING THE SYSTEM ONCE AGAIN IN A FAVORABLE OUTFLOW ENVIRONMENT. VWS REMAINS
LOW AND SSTS REMAIN FAVORABLE, WITH OUTFLOW BEING THE PRIMARY INTENSITY DRIVER
THROUGH TAU 72.
   C. BEYOND TAU 72, TD 14W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD ALONG
THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER STR TO THE NORTHEAST. AFTER TAU 72,
AN UPPER-LEVEL ANTICYCLONE DEVELOPS IN THE WAKE OF TD 14W AND TRAILS THE SYSTEM
THROUGH TAU 120, PROVIDING A MODERATE LEVEL OF WESTWARD AND POLEWARD OUTFLOW,
WHICH ALONG WITH LOW TO MODERATE (10-20 KNOTS) VWS AND HIGH SSTS (28-29 CELSIUS),
COMBINE TO ALLOW FOR STEADY INTENSIFICATION THROUGH THE FORECAST PERIOD. DYNAMIC
MODEL GUIDANCE IS IN GOOD AGREEMENT WITH ALL MODELS AGREEING ON THE GENERAL
NORTHWESTWARD TRACK AND ONLY SOME MINOR DIFFERENCES IN THE EXACT TRACK, LEADING
TO HIGH CONFIDENCE IN THE FORECAST TRACK. AVAILABLE INTENSITY GUIDANCE IS IN POOR
AGREEMENT, WITH THE HWRF AND COTC MODELS SHOWING RAPID INTENSIFICATION TO OVER 100
KNOTS BY TAU 120, AND THE DECAY SHIPS PEAKING OUT AT AROUND 75 KNOTS. THE OFFICIAL
INTENSITY FORECAST LIES ABOUT 10 KNOTS LESS THAN THE INTENSITY CONSENSUS AND CLOSE
TO THE HWRF SOLUTION THROUGH TAU 96.//
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