WDXS31 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19S (GOMBE) WARNING 
NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.3S 36.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 459 NM NORTH-NORTHWEST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
  
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EXPOSED
LOW-LEVEL CIRCULATION (LLC) THAT HAS CONTINUED TO UNRAVEL AND
WEAKEN IN INTENSITY. THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE AS THE LLC IS OBSCURED BY MID AND HIGH-LEVEL CLOUDS.
VERY LITTLE CONVECTION REMAINS WITH TC 19S ON THE EASTERN AS
INDICATED USING THE 120415Z SSMIS 89GHZ IMAGE. THE INITIAL
INTENSITY OF 30KTS IS ASSESSED WITH LOW CONFIDENCE DUE TO A LACK OF
OBJECTIVE AND SUBJECTIVE AIDS DUE TO THE SYSTEM REMAINING OVERLAND.
THE OVERALL CONVECTIVE STRUCTURE HAS CONTINUED TO UNRAVEL OVER THE
RUGGED TERRAIN OF MOZAMBIQUE. ALTHOUGH THE LOW (5-10KT) VWS AND
UPPER-LEVEL OUTFLOW ARE BOTH FAVORABLE, THE LACK OF A MOISTURE
SOURCE AND TERRAIN INFLUENCE DECREASE THE OVERALL ENVIRONMENT TO
UNFAVORABLE. TC 19S WILL CONTINUE TRACKING ALONG THE NORTHWEST
PERIPHERY OF THE STR TO THE SOUTHEAST.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
SOUTHEAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 5-10 KTS
   SST: OVER LAND
   OUTFLOW: WEAK RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: LOW
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE EXTENDED FORECAST INTENSITIES
OVER THE MOZAMBIQUE CHANNEL HAS BEEN INCREASED TO ABOVE 35 KTS;
OTHERWISE, THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE 
PREVIOUS WARNING. 

FORECAST DISCUSSION: TC 19S IS STRUGGLING TO REMAIN INTACT AS IT
MOVES OVER THE RUGGED TERRAIN OF MOZAMBIQUE. TC 19S IS EXPECTED TO 
RECURVE TO THE SOUTHWEST AS IT BEGINS ROUNDING THE FAR WESTERN EDGE 
OF THE STR AXIS TO THE EAST-SOUTHEAST THROUGH THE NEXT 36-48 HOURS. 
BY TAU 48, OR SLIGHTLY AFTER, TC 19S IS EXPECTED TO REGAIN ITS 
MOISTURE SOURCE AS IT ENTERS BACK OVER THE MOZAMBIQUE CHANNEL NEAR 
QUELIMANE AS A WEAK TROPICAL DEPRESSION AND THEN WILL REGAIN 
INTENSITY TO TROPICAL STORM STRENGTH OVER THE NEXT 72-120 HOURS.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN BROAD AGREEMENT WITH THE
TRACK UP TO THE FIRST 36 TO 48 HOURS. AFTERWARD, THE MODELS BEGIN
TO DIVERGE SIGNIFICANTLY, AS THE SYSTEM EXITS THE COAST NEAR
QUELIMANE AND THE MOUTH OF RIO ZAMBEZE INTO THE WARM WATERS OF THE
MOZAMBIQUE CHANNEL. A BIFURCATION BEGINS TO FORM AT TAU 72 WITH
GFS, AFUM, AND UEMN MOVING THE SYSTEM TO THE NORTHEAST, WHILE THE
REST OF THE MODELS AND ECMF ENSEMBLES MOVE THE SYSTEM SOUTHWEST.
THE INTENSITY GUIDANCE IS ALSO LIMITED AS A RESULT OF THE WEAK
VORTEX BEFORE IT REEMERGES OVER THE CHANNEL. HWRF SHOWS THE EXTREME
OF 115KTS AS IT INDICATES A POSSIBLE RAPID INTENSIFICATION SCENARIO
BY TAU 108, WHILE COTC IS ONLY EXPECTING THE SYSTEM TO REMAIN UNDER
25KTS FOR THE DURATION OF THE FORECAST. DUE TO THIS UNCERTAINTY,
THERE IS OVERALL LOW CONFIDENCE IN THE JTWC TRACK AND INTENSITY
FORECASTS. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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