WDPS31 PGTW 072100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 30P (MAILA) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.5S 156.0E
   INITIAL INTENSITY: 125 KTS
   GEOGRAPHIC REFERENCE: 743 NM NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 30P WITH A WELL-DEFINED, CLEAR, AND SYMMETRIC EYE
APPROXIMATELY 24 NM IN DIAMETER EMBEDDED IN A SLIGHTLY ASYMMETRIC
UPPER LEVEL CANOPY WITH THE STRONGEST DEEP CONVECTION ALONG THE
WESTERN SEMICIRCLE. A 071749Z SSMIS MICROWAVE IMAGE CONFIRMS THE
EYE IS SYMMETRICAL THROUGHOUT THE VERTICAL COLUMN, AND THE CORE IS
VERTICALLY STACKED WITH NO TILT WITH HEIGHT. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE AND AFOREMENTIONED
071749Z SSMIS IMAGE. THE STORM IS ASSESSED TO HAVE RAPIDLY
INTENSIFIED OVER THE PAST 24 HOURS, INTENSIFYING FROM 9O KTS AT
061800Z TO NOW 125 KTS AT 071800Z. ENVIRONMENTAL ANALYSIS REVEALS A
FAVORABLE ENVIRONMENT CHARACTERIZED MY LOW (10-15 KTS) VERTICAL
WIND SHEAR (VWS), WARM (29-30 KTS) SEA SURFACE TEMPERATURES, AND
MODERATE OUTFLOW ALOFT. ANY COLD WATER UPWELLING CAUSED BY THE
STORM'S QUASISTATIONARY TRACK APPEARS TO HAVE LITTLE TO NO EFFECT
ON THE CURRENT INTENSIFICATION TREND. THE INITIAL INTENSITY OF 125
KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AUTOMATED CIMSS
INTENSITY ESTIMATES AND THE AGENCY SUBJECTIVE DVORAK FIXES LISTED
BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE SOUTHWEST AND CENTERED OVER AUSTRALIA

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   KNES: T6.5 - 127 KTS
   ABRF: T6.0 - 115 KTS
   CIMSS SATCON: 125 KTS AT 071600Z
   CIMSS ADT: 127 KTS AT 071830Z
   CIMSS AIDT: 122 KTS AT 071830Z
   CIMSS D-MINT: 119 KTS AT 071748Z
   CIMSS D-PRINT: 121 KTS AT 071830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TC 30P (MAILA) IS EXPECTED TO SLOWLY TRACK
WEST-NORTHWESTWARD FROM THE NEXT 24-36 HOURS WHILE IT REMAINS IN
THE RELATIVELY WEAK STEERING ENVIRONMENT OF THE NORTHEASTERN
PERIPHERY OF THE STR CENTERED OVER AUSTRALIA. AROUND TAU 48, THE
STR IS EXPECTED TO BUILD A EASTWARD EXTENSION THAT WILL CAUSE 30P
TO INCREASE TRANSLATION SPEED AND ACCELERATE SOUTHWESTWARD TOWARD
CAPE YORK FOR THE REMAINDER OF THE FORECAST PERIOD. REGARDING
INTENSITY, MAILA IS FORECAST TO REMAIN AT A STABLE INTENSITY
THROUGH TAU 24 WHILE IT'S SUSTAINED BY THE SUPPORTIVE ENVIRONMENT.
WHILE 30P REMAINS QUASISTATIONARY, COLD WATER UPWELLING IS A
POTENTIAL WEAKENING FACTOR, WITH A DEVELOPED COLD WAKE (SUB 26C)
DEPICTED IN THE HAFS-A MODELS IN CLOSE PROXIMITY TO THE ASSESSED
POSITION. THE CURRENT FORECAST TRACK DEPICTS 30P TRANSITING NORTH
OF THE MODEL-DERIVED COLD POOL IN HAFS-A, INDICATING THE
POSSIBILITY THAT 30P WILL MISS ITS COLD WAKE ENTIRELY AS IT
MEANDERS NORTHWESTWARD THROUGH TAU 24. ONCE 30P TURNS SOUTHWESTWARD
AT TAU 24-36, IT WILL ENCOUNTER UPWARDS OF 35KTS OF MIDLEVEL SHEAR,
BATTERING THE STORM THROUGH TAU 72. THE MIDLEVEL SHEAR IS EXPECTED
TO LET UP SLIGHTLY BETWEEN TAU 72-120, BUT REMAIN ELEVATED ENOUGH
TO PREVENT SIGNIFICANT REINTENSIFICATION AT THE END OF THE FORECAST
PERIOD. MAILA'S CLOSE BRUSH WITH THE PAPAUN PENINSULA WILL BE
ADDITIONAL CONTRIBUTOR TO WEAKENING, INDUCING TERRAIN INTERACTION
AS 30P SCRAPES IT WESTERN FLANK ALONG THE OWEN STANLEY RANGE.

MODEL DISCUSSION: DETERMINISTIC TRACK MODEL GUIDANCE IS IN MODERATE
AGREEMENT OVERALL, WITH LARGE DISCREPANCIES IN HOW EACH MODEL
DEPICTS THE QUASISTATIONARY PERIOD INTO THE SOUTHWESTWARD
ACCELERATION, INDUCING A LARGE (575 NM) ALONG-TRACK SPREAD AT TAU
120. AS A RESULT, THE JTWC TRACK FORECAST IS PLACED CLOSE THE THE
MULTI-MODEL CONSENSUS WITH OVERALL MEDIUM CONFIDENCE. RELIABLE
INTENSITY GUIDANCE ARE IN STRONG AGREEMENT THAT 30P HAS REACHED ITS
PEAK INTENSITY AND WILL GRADUALLY WEAKEN UNTIL THE END OF THE
FORECAST PERIOD. NOTABLY, THE MESOSCALE MODELS (HAFS-A AND HWRF)
DEPICT A MUCH MORE DRASTIC WEAKENING TREND THROUGH TAU 24. THE JTWC
INTENSITY FORECAST IS ASSESSED WITH OVERALL LOW CONFIDENCE, AS A
RESULT OF THE UNCERTAINTIES REGARDING POTENTIAL INTERACTION WITH
THE COLD POOL AND THE MAGNITUDE OF THE MID-LEVEL SHEAR THE STORM
WILL ENCOUNTER AS IT TRANSITS SOUTHWESTWARD.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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