Tropical Storm FAXAI Advisory Sun Sep 01

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FOURTEEN) WARNING NR 1//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 14W (FOURTEEN), LOCATED APPROXIMATELY
310 NM SOUTHEAST OF WAKE ISLAND, HAS TRACKED WESTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A VERY COMPACT SYSTEM WITH PERSISTENT, FLARING DEEP CONVECTION
OBSCURING THE LOW-LEVEL CIRCULATION. A 011750Z AMSU-B 89 GHZ MICROWAVE PASS SHOWED
A VERY SMALL CORE CIRCULATION, WITH DEEP CONVECTION TO THE SOUTH. EXPOSED LOW-LEVEL
BANDING ON THE NORTH SIDE OF THE CONVECTIVE BALL CAN BE SEEN WRAPPING INTO AN OBSCURED LLC,
 AND TOGETHER WITH THE AMSU-B MICROWAVE IMAGE PROVIDE SUPPORT TO THE MODERATE CONFIDENCE INITIAL
 POSITION. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED WITH FAIR CONFIDENCE BASED ON DVORAK
 CURRENT INTENSITY ESTIMATES OF T2.0 (30 KNOTS) FROM KNES, AND T1.5 (25 KNOTS) FROM PGTW AND RJTD.
 ENVIRONMENTAL ANALYSIS REVEALS THE SYSTEM LIES IN A FAVORABLE REGION, WITH LOW (5-10 KNOTS) VWS,
 MODERATE TO STRONG POLEWARD OUTFLOW BEING PROVIDED BY A NEARBY TUTT CELL TO THE NORTHWEST,
 AND WARM SSTS (28-30C). TD 14W IS CURRENTLY TRACKING SLOWLY WESTWARD ALONG THE SOUTHERN PERIPHERY OF
A SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND SETS THE
FORECAST PHILOSOPHY.
   B. IN THE NEAR TERM, TD 14W WILL TRACK SLOWLY WESTWARD BEFORE TURNING MORE WEST-NORTHWESTWARD
OVER THE NEXT 12 HOURS. THE STEERING RIDGE IS EXPECTED TO MAINTAIN TO THE NORTH OF THE SYSTEM,
 LEADING TO A STEADY NORTHWESTWARD TRACK THROUGH TAU 72. FROM AN INTENSITY PERSPECTIVE, THE TUTT
 CELL CURRENTLY TO THE NORTHWEST WILL CONTINUE TO MOVE WESTWARD LEAVING TD 14W IN A FAVORABLE POSITION
 AND ABLE TO TAP INTO DIVERGENT POLEWARD OUTFLOW, LEADING TO STEADY INTENSIFICATION THROUGH TAU 36.
 FROM TAU 48 THROUGH 72, TD 14W WILL MOVE INTO A LESS FAVORABLE POSITION IN RELATION TO THE TUTT CELL,
 WHICH WILL LEAD TO A DECREASE IN OUTFLOW. WHILE VWS WILL REMAIN LOW AND SSTS REMAIN HIGH, THESE
 FAVORABLE FACTORS WILL BE OFFSET BY THE REDUCTION IN OUTFLOW, LEADING TO A LEVELING OFF OF THE
INTENSITY DURING THIS PERIOD.
   C. TD 14W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD ALONG THE SOUTHWESTERN
PERIPHERY OF A DEEP STR TO THE NORTHEAST. AFTER TAU 72, THE UPPER-LEVEL PATTERN
 BECOMES HIGHLY COMPLEX WITH THE AFOREMENTIONED TUTT CELL DISSIPATING AND MOVING
AWAY, WHILE AN UPPER-LEVEL ANTICYCLONE DEVELOPS JUST TO THE EAST OF THE SYSTEM.
THE RESULT WILL BE TO PLACE TD 14W IN ANOTHER DIVERGENT OUTFLOW PATTERN, WHICH WHEN
 COMBINED WITH HIGH SSTS AND LOW TO MODERATE (10-15 KNOTS) VWS, WILL LEAD TO ANOTHER
ROUND OF INTENSIFICATION, PEAKING AT 50 KNOTS BY TAU 120. DYNAMIC MODEL GUIDANCE IS IN
FAIRLY 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.//
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