WDXS31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19S (GOMBE) WARNING 
NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.9S 42.1E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 393 NM NORTH-NORTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT THE
SYSTEM CONTINUES TO CONSOLIDATE AND STRENGTHEN, BUT YET UNABLE TO
SUSTAIN AN EYE IN THE EIR OR VISIBLE IMAGERY. A FORTUITOUS 101105Z
AMSR2 PASS SHOWED WELL DEFINED, VERTICALLY STACKED MICROWAVE EYE
FEATURES IN BOTH THE 37GHZ AND 89GHZ BANDS WITH DEEP CONVECTIVE
BANDS WRAPPING IN THE FROM THE NORTH AND WEAKER, MORE ILL-DEFINED
BANDING TO THE SOUTH. THE MICROWAVE IMAGERY SUGGESTS A COMPLETE
EYEWALL, PARTICULARLY IN THE 36GHZ BAND, BUT WEAKER ON THE
SOUTHWEST SIDE. THE HIGH RESOLUTION HWRF SHOWS A POCKET OF
RELATIVELY DRIER AIR ON THE SOUTHERN SIDE OF THE EYE, AND THE
MICROWAVE IMAGERY SEEMS TO CONFIRM THIS. THE PRESENCE OF THIS DRY
AIR IS LIKELY ONE FACTOR KEEPING A LID ON THE INTENSIFICATION RATE
OF THIS SYSTEM AT PRESENT. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON AN EXTRAPOLATION OF THE MICROWAVE EYE IN
THE AMSR2 DATA. THE INITIAL CONFIDENCE IS ASSESSED WITH HIGH
CONFIDENCE AS WELL, IN LINE WITH THE T4.5 DVORAK CURRENT INTENSITY
ESTIMATES FROM BOTH PGTW AND FMEE, AS WELL AS AN AIDT ESTIMATE OF
74 KNOTS (WELL ABOVE THE ADT ESTIMATE IN THIS INSTANCE) AND THE
MAXIMUM WIND OF 74 KNOTS SEEN IN THE AMSR2 WINDSPEED PRODUCT.

INITIAL WIND RADII BASIS: AMSR2 WINDSPEED PRODUCT. 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE SOUTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   FMEE: T4.5 - 77 KTS
   CIMSS SATCON: 62 KTS AT 101117Z
   CIMSS ADT: 61 KTS AT 101215Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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: OVER THE PAST 6-12 HOURS, TC 19S HAS TAKEN A
BIT MORE OF A SOUTHWESTERLY JOG THAN PREVIOUSLY ANTICIPATED. WHILE
THE PREDOMINANT STEERING MECHANISM REMAINS THE STR TO THE SOUTH, A
NEAR-EQUATORIAL RIDGE (NER) TO THE NORTH IS SLIGHTLY STRONGER THAN
ANTICIPATED AND IS IMPARTING A STEERING PRESSURE FROM THE NORTH.
HOWEVER, IN THE NEAR-TERM THE STR TO THE SOUTH IS ANTICIPATED TO
STRENGTHEN AGAIN AND THE SOUTHWESTERLY MOTION SHOULD BE ARRESTED,
WITH TC 19S RESUMING A MORE WESTWARD TRACK THROUGH TAU 48. THE
SYSTEM IS FORECAST TO MAKE LANDFALL SHORTLY AFTER TAU 12 IN THE
VICINITY OF ANGOCHE, MOZAMBIQUE, THEN MOVING SLOWLY WESTWARD
THROUGH TAU 48 AS THE STEERING PATTERN WEAKENS. ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO REMAIN VERY FAVORABLE THROUGH LANDFALL,
WITH VERY WARM (30-31C) SSTS, LOW VWS AND STRONG OUTFLOW ALOFT,
WITH A PEAK INTENSITY OF 100 KNOTS EXPECTED JUST PRIOR TO LANDFALL.
ONCE INLAND, EVEN THOUGH THE SYSTEM WILL RAPIDLY WEAKEN, IT IS
EXPECTED TO BRING COPIOUS AMOUNTS OF RAINFALL AND INDUCE MAJOR
FLOODING OVER NORTH-CENTRAL MOZAMBIQUE AND SURROUNDING AREAS. BY
TAU 48 THE STEERING PATTERN WILL BEGIN TO SHIFT, AS THE STR TO THE
SOUTH ERODES, MOVES EAST AND REORIENTS TO A NORTH-SOUTH AXIS AHEAD
OF AN APPROACHING MID-LATITUDE TROUGH. IN RESPONSE, THE REMNANTS OF
TC 19S WILL TURN SHARPLY POLEWARD AFTER TAU 48, AND SHOULD EMERGE
BACK OVER WATER SHORTLY AFTER TAU 72. CONDITIONS OVER THE CENTRAL
PORTION OF THE MOZAMBIQUE CHANNEL ARE EXPECTED TO BE FAVORABLE FOR
TC DEVELOPMENT, AND THE REMNANTS OF TC 19S ARE FORECAST TO ONCE
AGAIN INTENSIFY, PEAKING AT 45 KNOTS BY TAU 120. 

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS VERY
GOOD AGREEMENT THROUGH LANDFALL AND UP TO TAU 36, AND SUPPORTS THE
JTWC FORECAST IN THIS SEGMENT OF THE FORECAST WITH HIGH CONFIDENCE.
AS THE SYSTEM RAPIDLY WEAKENS AND THE STEERING PATTERN BEGINS TO
SHIFT, THE MODEL GUIDANCE SHOWS DRAMATICALLY DECREASED CONFIDENCE,
WITH A WIDE SPREAD OF SOLUTIONS, PARTICULARLY IN THE ENSEMBLE
GUIDANCE. THE NAVGEM AND HWRF REMAIN THE TWO OUTLIERS, KEEPING THE
SYSTEM OVER LAND FOR THE ENTIRE DURATION OF THE FORECAST. THE
REMAINDER OF THE GUIDANCE PACKAGE CONCURS ON A TURN SOUTHEASTWARD
AFTER TAU 48, BUT DIFFERS IN THE TIMING AND SHARPNESS OF THE TURN.
THE JTWC FORECAST TRACK REMAINS CONSISTENT WITH THE PREVIOUS
FORECAST, AND LIES ON THE EASTERN SIDE OF THE ENVELOPE WITH LOW
CONFIDENCE AFTER TAU 48. INTENSITY GUIDANCE IS IN OVERALL GOOD
AGREEMENT BUT HAS COME DOWN IN THE PEAK AGAIN, WITH ALL
DETERMINISTIC GUIDANCE PEAKING BELOW 95 KNOTS BEFORE LANDFALL. THE
RIDE RAPID INTENSIFICATION (RI) AID IS THE SOLE REMAINING RI AID TO
BE TRIGGERED. THE JTWC FORECAST LIES ABOVE ALL OF THE GUIDANCE WITH
THE EXCEPTION OF THE RIDE THROUGH LANDFALL, THEN SLIGHTLY ABOVE THE
CONSENSUS THROUGH THE OVER LAND PHASE. THE MAJORITY OF THE
DETERMINISTIC GUIDANCE INDICATES LITTLE TO NO INTENSIFICATION AFTER
TAU 96, BUT THE COAMPS-TC, ECENS AND GEFS ENSEMBLE INTENSITY
GUIDANCE INDICATES A 20-30 PERCENT PROBABILITY OF MODERATE
INTENSIFICATION AND A 10-15 PERCENT PROBABILITY OF RI, LENDING
INCREASED CONFIDENCE TO THE LONG-RANGE FORECAST. HOWEVER, THERE IS
LOW CONFIDENCE IN THE FORECAST INTENSITY AFTER TAU 48 DUE TO THE
UNCERTAIN EFFECTS OF PROLONGED PERIODS OVER LAND AND THE ULTIMATE
INTENSITY OF THE REMNANTS THAT EMERGE BACK OVER WATER. 

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