WDXS31 PGTW 180300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 29S (ERROL) WARNING NR 
026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.0S 123.3E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 130 NM NORTH-NORTHEAST OF BROOME,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: EASTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS RAPIDLY
DETERIORATING TROPICAL CYCLONE (TC) 29S (ERROL) TRACKING EASTWARD
TOWARD THE KIMBERLEY COAST. ENVIRONMENTAL ANALYSIS REVEALS
PERSISTENT UNFAVORABLE CONDITIONS, WITH 25-30 KTS VERTICAL WIND
SHEAR (VWS) AND BROAD AREA OF DRY AIR PUSHING INTO THE CORE OF THE
VORTEX. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED
ON THE SURFACE WIND OBSERVATIONS FROM ADELE ISLAND INDICATING
PASSING OF THE LOW-LEVEL CIRCULATION CENTER (LLCC) JUST SOUTH OF
THE SITE, WITHIN THE LAST 3 HOURS, AS WELL AS VISIBLE SATELLITE 
IMAGERY LOOP. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON THE COMBINATION OF AGENCY DVORAK ESTIMATES AND 
OBJECTIVE AIDS LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: PASSING LONG WAVE TROUGH TO THE SOUTH
OF THE SYSTEM AND ASSOCIATED DEEP-LAYER WESTERLY FLOW

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   CIMSS ADT: 59 KTS AT 172330Z
   CIMSS AIDT: 58 KTS AT 172330Z
   CIMSS D-MINT: 31 KTS AT 172207Z
   CIMSS D-PRINT: 30 KTS AT 180000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: LAND INTERACTION AND DRY AIR INTRUSION FROM THE
WEST

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: SINCE LAST FORECAST, THE LLCC OF TC ERROL
ALIGNED WITH THE AXIS OF THE PASSING LONG WAVE TROUGH TO THE SOUTH,
RESULTING IN A TEMPORARILY EASTWARD PROPAGATION OF THE SYSTEM. 
MAJORITY OF AVAILABLE GUIDANCE PREDICTS A SLIGHT SOUTH-SOUTHEASTWARD 
TURN, FOLLOWED BY A LANDFALL IN PROXIMITY OF THE WALCOTT INLET, AS 
PICTURED BY THE JTWC TRACK FORECAST. PERSISTENT UNFAVORABLE 
CONDITIONS AMPLIFIED BY LAND INTERACTION AND EVENTUAL LACK OF ENERGY 
SOURCE WILL LEAD TO CONTINUOUS WEAKENING AND DISSIPATION IS EXPECTED 
TO OCCUR BY TAU 12. REMNANTS OF THE SYSTEM WILL CONTINUE INLAND, WITH 
NO EXPECTATION OF RECURVING MOTION OR REGENERATION.

MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH CROSS-TRACK SPREAD AT LANDFALL OF JUST 40 NM. THE
MAIN OUTLIER IS DETERMINISTIC ECMWF GUIDANCE PREDICTING A SLIGHTLY
NORTHEASTWARD TRACK AND LANDFALL CLOSER TO STORR ISLAND. JTWC
FORECAST IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS CENTERED WITHIN
A 25 NM CROSS-TRACK SPREAD ASSOCIATED WITH THE REMAINING MEMBERS OF
THE CONSENSUS GUIDANCE. INTENSITY MODEL ESTIMATES CONTINUE TO SUPPORT
RAPID WEAKENING ACROSS ALL AVAILABLE MODELS AND THEREFORE JTWC
FORECAST IS ASSESSED WITH HIGH CONFIDENCE AND PLACED ALSO WITHIN
CLOSE PROXIMITY OF THE CONSENSUS.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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