WDPS31 PGTW 100300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 30P (MAILA) WARNING NR 
017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.1S 154.6E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 737 NM NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 30P (MAILA) WITH DISORGANIZED CONVECTION OFFSET TO THE WEST
OF THE LOW-LEVEL CIRCULATION CENTER. A 092033Z F16 SSMIS 91 GHZ
MICROWAVE IMAGE REVEALED EXPOSED LOW-LEVEL CLOUD LINES WITHIN THE
EASTERN AND SOUTHERN PERIPHERIES WRAPPING INTO THE CENTER. THE
SSMIS IMAGE ALSO SHOWED CONVECTIVE BANDING HAS LARGELY DISSIPATED
AND IS NOW LOCATED WITHIN A SMALL AREA TO THE NORTH OF THE ASSESSED
CENTER. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED
ON THE SSMIS IMAGE AND ANIMATED MSI. A PARTIAL 091930Z RCM-3 SAR
IMAGE SHOWED WINDS OF 85-95 KTS WITHIN THE EASTERN PORTION OF THE
CIRCULATION. THE INITIAL INTENSITY OF 70 KTS IS ASSESSED WITH LOW
CONFIDENCE BASED ON A CONTINUED WEAKENING TREND FROM THE TIME OF
THE SAR IMAGE, ALONG WITH THE AGENCY DVORAK AND CIMSS INTENSITY
ESTIMATES LISTED BELOW. ENVIRONMENTAL ANALYSIS INDICATES THAT 30P
IS IN AN UNFAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE WESTWARD
OUTFLOW ALOFT, MODERATE TO HIGH (20-25 KTS) EASTERLY VERTICAL WIND
SHEAR, AND COLD SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF AN EASTERN
EXTENSION OF THE DEEP-LAYER SUBTROPICAL RIDGE (STR) POSITIONED OVER
NORTHERN AUSTRALIA 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   ABRF: T4.5 - 77 KTS
   CIMSS ADT: 77 KTS AT 100010Z
   CIMSS AIDT: 64 KTS AT 100010Z
   CIMSS D-MINT: 70 KTS AT 092212Z
   CIMSS D-PRINT: 51 KTS AT 100010Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 22-24 CELSIUS
   OUTFLOW: MODERATE WESTWARD
   OTHER FACTORS: THE SYSTEM IS CURRENTLY OVER A POOL OF COLD SEA
SURFACE TEMPERATURES DUE TO UPWELLING EFFECTS 

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: LOW
   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 IS FORECAST TO DRIFT SOUTHWESTWARD
ALONG THE NORTHERN PERIPHERY OF A BUILDING RIDGE TO THE SOUTHEAST
THROUGHOUT THE ENTIRE FORECAST PERIOD. THE RIDGE IS NOT EXPECTED TO
BE FULLY BUILT IN UNTIL AROUND TAU 72, SO TRACK SPEEDS ARE FORECAST
TO BE SLOW MOVING. THERE REMAINS A SIGNIFICANT AMOUNT OF UNCERTAINTY 
IN THE ACTUAL DIRECTION THAT 30P TAKES AS MODELS SHOW THE SYSTEM 
TRACKING IN WIDE RANGE OF POSSIBLE TRAJECTORIES. THERE IS A CHANCE 
THAT 30P FALLS APART MORE QUICKLY IN A LOCATION CLOSER TO ITS CURRENT 
POSITION. REGARDING INTENSITY, 30P IS FORECAST TO CONTINUE WEAKENING 
UNDER THE EFFECTS OF PERSISTENT EASTERLY SHEAR AND COOL SEA SURFACE 
TEMPERATURES CAUSED BY UPWELLING. THERE IS ALSO SIGNIFICANT 
UNCERTAINTY IN THE TIMING OF DISSIPATION. IF THE SYSTEM STAYS IN 
PLACED LONGER THAN ANTICIPATED, A MUCH EARLIER DISSIPATION COULD 
OCCUR. AS IT STANDS, THE JTWC INTENSITY FORECAST CALLS FOR DISSIPATION 
NEAR THE TIP OF THE PAPUAN PENINSULA NO LATER THAN TAU 96. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN VERY
POOR AGREEMENT WITH A GENERAL CONSENSUS ON A WEST-SOUTHWESTWARD
TRACK, BUT EXTREME VARIATIONS IN TRACK SPEEDS BETWEEN MODELS. 
ADDITIONALLY, THERE REMAIN OUTLIERS SUCH AS THE EC-AIFS, WHICH TRACK 
THE VORTEX NORTHWARD VICE SOUTHWESTWARD. THE JTWC TRACK FORECAST IS 
PLACED NEAR THE ECMWF AND GOOGLE DEEPMIND ENSEMBLE MEANS WITH LOW 
CONFIDENCE. INTENSITY GUIDANCE DOES AGREE ON WEAKENING, BUT AT 
VARYING RATES. HWRF HAS THE SYSTEM DROPPING BELOW 35 KTS AT TAU 48 
WHILE SOME OF THE GLOBAL DETERMINISTIC MODELS HOLD ONTO THE VORTEX 
FOR LONGER, SUCH AS ECMWF. THE JTWC INTENSITY FORECAST IS PLACED NEAR 
THE MULTI-MODEL CONSENSUS WITH LOW CONFIDENCE DUE TO THE POSSIBILITY 
OF A MUCH EARLIER DISSIPATION TIMELINE. 

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