WDPS31 PGTW 241500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01P (LOLA) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.6S 168.3E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 126 NM NORTH OF PORT VILA, VANUATU
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT
TROPICAL CYCLONE (TC) 01P (LOLA) HAS BEEN ABLE TO MAINTAIN A SMALL
AND RAGGED CENTRAL DENSE OVERCAST (CDO) OVER THE PAST FEW HOURS BUT
HAS NOT BEEN ABLE TO REFORM AND EYE IN THE EIGHT HOURS. GLOBAL
LIGHTNING DATA SHOWS A LARGE BURST OF LIGHTNING OCCURRING ACROSS
THE SOUTHERN PORTION OF THE INNER CORE OVER THE PAST HOUR OR TWO,
BUT THE ASSOCIATED DEEP CONVECTION HAS FAILED TO WRAP UP THE WEST
SIDE. THE LAST USABLE MICROWAVE IMAGE WAS A 241050Z AMSU-B 89GHZ
IMAGE, WHICH UNFORTUNATELY DID NOT PROVIDE MUCH CLARITY TO THE
STRUCTURE OF THE SYSTEM DUE TO THE LOW RESOLUTION BUT DID SHOW THAT
THE BULK OF THE DEEP CONVECTION IS CONFINED TO THE SOUTH AND EAST
OF THE CENTER. A 241050Z ASCAT-B PASS SHOWED THE LOW LEVEL
CIRCULATION CENTER (LLCC) TO BE JUST EAST OF THE NORTHERN TIP OF
PENTECOST ISLAND. THE INITIAL POSITION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE LLCC SEEN IN THE ASCAT-B PASS AND THE
ACCOMPANYING AMSU-B IMAGE. ANALYSIS OF TWO COINCIDENT SAR PASSES (A
240702Z RCM-1 AND A 240714Z SENTINEL-1A) WHICH SHOWED MAX WINDS IN
THE SOUTHERN QUADRANT OF 127 KTS AND 113 KTS RESPECTIVELY, HAS LED
TO A REANALYSIS OF THE 0600Z INTENSITY TO 120 KNOTS. THE INITIAL
INTENSITY FOR 1200Z IS SET AT 110 KNOTS WITH MEDIUM CONFIDENCE, AT
THE AVERAGE OF THE AGENCY DVORAK CURRENT INTENSITY ESTIMATES,
SUPPORTED BY THE CIMSS ADT, AIDT AND DPRINT ESTIMATES OUTLINED
BELOW. THE ENVIRONMENT IS BECOMING INCREASINGLY MARGINAL, WITH
DEEP-LAYER SHEAR HAVING PICKED UP SHARPLY OVER THE PAST FEW HOURS.
DRY MID- TO UPPER-LEVEL AIR IS STILL AN ISSUE, AT LEAST ACCORDING
TO THE CIRA ADVECTED LAYER PRECIPITABLE WATER PRODUCT AND MODEL
ANALYSIS FIELDS. THESE FACTORS ARE COMPETING WITH, BUT SLOWLY
COMING TO DOMINATE THE ROBUST POLEWARD OUTFLOW AND WARM SSTS.

INITIAL WIND RADII BASIS: SCATTEROMETER AND SAR DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED NEAR SAMOA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   KNES: T6.0 - 115 KTS
   PHFO: T6.0 - 115 KTS
   NFFN: T6.0 - 115 KTS
   CIMSS SATCON: 88 KTS AT 241300Z
   CIMSS ADT: 109 KTS AT 241130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY MID- TO UPPER-LEVEL AIR.

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: ANALYSIS OF THE MOST RECENT ANIMATED IMAGERY
SUGGESTS THAT TC 01P HAS SLOWED DOWN TO A CRAWL AS IT APPROACHES
PENTECOST ISLAND, BUT WITHOUT A CLEAR VIEW BELOW THE CDO, OR
SURFACE OBSERVATIONS, IT IS IMPOSSIBLE TO TELL IF THE LLCC HAS
PASSED PENTECOST ISLAND YET OR NOT. ADDITIONAL ERRATIC MOTION CAN
BE EXPECTED AS THE SYSTEM MOVES INTO THE AREA BETWEEN PENTECOST AND
MALEKULA ISLANDS BUT OVERALL THE SYSTEM IS FORECAST TO TRACK
SOUTHWEST ALONG THE PERIPHERY OF THE STEERING RIDGE TO THE EAST,
THROUGH THE NEXT 36 HOURS. AROUND TAU 36, TC 01P WILL TURN TOWARDS
THE SOUTH AND THEN EVENTUALLY SOUTHEAST BY TAU 72, AS IT TRACKS
ALONG THE GRADIENT BETWEEN THE STR TO THE NORTHEAST AND AN
APPROACHING MID-LATITUDE LOW PRESSURE SYSTEM MOVING IN FROM THE
WEST. THE SYSTEM IS ALREADY STARTING TO WEAKEN FAIRLY QUICKLY AS IT
MOVES SOUTHWEST INTO A MORE HOSTILE ENVIRONMENT. GLOBAL MODEL
FIELDS SHOW THAT MID-LEVEL SHEAR IS RUNNING AT AROUND 30 KNOTS,
WHICH MAY BE A BIT AGGRESSIVE BASED ON THE SATELLITE PRESENTATION,
WHICH AS OF YET SHOWS NO SIGN OF A DECOUPLING OF THE VORTEX THOUGH
THERE CERTAINLY IS A FAIR AMOUNT OF VORTEX TILT. MID-LEVEL FLOW
FROM THE NORTHWEST IS DRAGGING WITH IT AN EXTREMELY DRY AIR MASS,
WHICH IS LURKING JUST WEST OF THE SYSTEM FOR THE MOMENT. GLOBAL
MODEL FIELDS SUGGEST THIS MID-LEVEL FLOW WILL INCREASE SHARPLY
WITHIN THE NEXT 12 TO 24 HOURS, BOTH INCREASING THE SHEAR AS WELL
AS ALLOW FOR THE DRY AIR TO PENETRATE INTO THE CORE OF THE SYSTEM.
THE EFFECTS WILL BE DRAMATIC, WITH A RAPID AND FULL DECOUPLING OF
THE VORTEX EXPECTED BY TAU 36. THE SYSTEM WILL RAPIDLY WEAKEN AS A
RESULT, WITH A NAKED REMNANT VORTEX PASSING OVER NEW CALEDONIA
BETWEEN TAU 48 AND 72. OF NOTE, THE SYSTEM WILL DISSIPATE BELOW
WARNING CRITERIA JUST PRIOR TO IT BEGINNING EXTRATROPICAL
TRANSITION AS IT MERGES WITH THE STRONG BAROCLINIC SYSTEM MOVING IN
FROM THE WEST. 

MODEL DISCUSSION: TRACK GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT,
WITH THE EXCEPTION OF THE NAVGEM AND GALWEM, WHICH CONTINUE TO BE
EXTREME OUTLIERS TO THE EAST AND WEST RESPECTIVELY. BOTH OF THESE
MODELS HAVE BEEN DISCARDED FROM THE CONSENSUS. THE REMAINDER OF THE
GUIDANCE CONTINUES TO BE WELL-CONSTRAINED, WITH THE ENVELOPE
GRADUALLY EXPANDING TO JUST 145NM AT TAU 72. THE JTWC FORECAST
CONTINUES TO LIE TO THE EAST OF THE CONSENSUS MEAN, AND CLOSE TO
THE ECMWF FORECAST TRACK, WITH HIGH CONFIDENCE THROUGH THE FORECAST
PERIOD. INTENSITY GUIDANCE REMAINS IN GOOD AGREEMENT WITH ALL
MODELS SHOWING A SHARP AND RAPID DECREASE IN INTENSITY THROUGH TAU
72. SEVERAL OF THE MODELS INCLUDING HAFS-A AND COAMPS-TC SHOW A
REINTENSIFICATION PERIOD STARTING AROUND TAU 72, BUT THIS IS DUE TO
BAROCLINIC FORCING AND NOT DUE TO TROPICAL EFFECTS. 

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