WDPS31 PGTW 050300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 30P (MAILA) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.8S 154.2E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 691 NM NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 30P (MAILA) MOVING SLOWLY WITH VIGOROUS BURSTS OF DEEP 
CONVECTION IN CLOSE PROXIMITY TO THE ASSESSED CENTER AND DEFINED
BANDING ALONG THE WESTERN PERIPHERY. A 041922Z RCM-2 SAR IMAGE
REVEALED THAT THE INTENSIFICATION RATE HAS BEEN FASTER THAN ORIGINALLY 
ANTICIPATED. THE SAR IMAGE SHOWED 65-70 KNOT WINDS SURROUNDING ALL BUT 
THE SOUTHWESTERN QUADRANT OF THE INNER-CORE. IT ALSO SHOWED AN 
ERRONEOUS PATCH OF 90 KNOT WINDS WITHIN A SMALL PORTION OF THE EASTERN 
SEMICIRCLE. A PARTIAL 042320Z METOP-C ASCAT PASS REVEALED A SOLID 
SWATH OF 50-55 KNOT BARBS TO THE EAST OF THE CENTER. THE INITIAL 
INTENSITY OF 65 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE 
SAR IMAGE AS WELL AS THE T3.5-4.0 AGENCY DVORAK FIXES. THE INITIAL 
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE ANIMATED MSI. 
ENVIRONMENTAL ANALYSIS INDICATES THAT 30P IS NOW IN A HIGHLY FAVORABLE 
ENVIRONMENT CHARACTERIZED BY STRONG OUTFLOW ALOFT, LOW (10-15 KTS) 
VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE TEMPERATURES. THE 
SLOW MOVEMENT OF THE SYSTEM HAS NOT LASTED LONG ENOUGH TO ALLOW FOR 
ANY UPWELLING EFFECTS TO HINDER THE SYSTEM.

INITIAL WIND RADII BASIS: PERSISTENCE FROM 041922Z RCM-2 SAR DATA 

CURRENT STEERING MECHANISM: COMPETING STEERING BETWEEN A
SUBTROPICAL RIDGE (STR) CENTERED OVER AUSTRALIA AND A
NEAR-EQUATORIAL RIDGE (NER) POSITIONED TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   ABRF: T3.5 - 55 KTS
   CIMSS SATCON: 54 KTS AT 042200Z
   CIMSS ADT: 63 KTS AT 050020Z
   CIMSS AIDT: 56 KTS AT 050020Z
   CIMSS D-PRINT: 59 KTS AT 050020Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE PEAK INTENSITY OF THE SYSTEM HAS
BEEN INCREASED TO 110 KTS. 

FORECAST DISCUSSION: TC 30P IS EXPECTED TO REMAIN WITHIN A COMPETING 
STEERING ENVIRONMENT, SQUISHED BETWEEN RIDGING TO BOTH THE NORTH AND 
SOUTH, THROUGH THE NEXT 96 HOURS. THROUGHOUT THIS TIME, ERRATIC TRACK 
MOTION IS POSSIBLE, THOUGH THE FORWARD ADVANCE SPEED WILL REMAIN SLOW. 
AFTER TAU 96, SOME MODELS SHOW THE RIDGING TO THE NORTH MOVING 
NORTHWARD, AWAY FROM THE SYSTEM, ALLOWING FOR THE STR OVER NORTHERN 
AUSTRALIA TO BECOME THE PRIMARY STEERING MECHANISM. ON THE OTHER HAND, 
OTHER MODELS DEPICT A QUASI-STATIONARY MOVEMENT WITHIN THE SOLOMON SEA 
THROUGHOUT THE ENTIRE 5-DAY FORECAST. THE JTWC FORECAST CALLS FOR A 
COUNTERCLOCKWISE LOOP THROUGH TAU 96, FOLLOWED BY THE BEGINNING OF A 
WESTWARD TRACK THROUGH TAU 120. IN TERMS OF INTENSITY, 30P IS FORECAST 
TO RAPIDLY INTENSIFY OVER THE NEXT 24-36 HOURS DUE TO THE HIGHLY 
FAVORABLE ENVIRONMENT. A PEAK INTENSITY OF 110 KTS IS FORECAST TO 
OCCUR AROUND TAU 48. AFTER TAU 48, THE SYSTEM WILL BEGIN TO FEEL THE 
EFFECTS OF UPWELLING COOLER WATERS, WHICH WILL INITIATE A WEAKENING 
TREND. THE WEAKENING TREND IS FORECAST TO PERSIST THROUGH TAU 120 AS 
TRACK SPEEDS REMAIN VERY SLOW, KEEPING THE VORTEX OVER THE COOLER 
WATERS. IF A TRACK IS SLIGHTLY FASTER WESTWARD, THEN THE VORTEX MAY BE 
ABLE TO TAP INTO WARMER WATERS SOONER, ALLOWING FOR REINTENSIFICATION.  

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN RELATIVELY
GOOD AGREEMENT THROUGH TAU 48, SHOWING A COUNTERCLOCKWISE LOOP. 
AFTER TAU 48, MODELS BEGIN TO DIVERGE WITH GFS BEING THE QUICKEST
TO ACCELERATE THE SYSTEM WESTWARD. THE EXPERIMENTAL GOOGLE DEEPMIND
ENSEMBLE MEAN AND THE EC-AIFS BOTH SHOW A TRACK NORTHWARD FROM TAU
48-120 RATHER THAN A TURN WESTWARD, CREATING SOMEWHAT OF A BIFURCATION 
IN GUIDANCE. BY TAU 120, GFS IS SOUTH OF PAPUA NEW GUINEA WHILE THE 
EC-AIFS IS WITHIN THE NORTHERN SOLOMON SEA, CREATING SIGNIFICANT 
UNCERTAINTY IN THE FORECAST TRACK. THE JTWC TRACK FORECAST IS PLACED 
NEAR THE TES1 CONSENSUS (WHICH ACCOUNTS FOR THE VARIOUS AI MODELS) 
THROUGH TAU 72, AND THEN HEDGED CLOSER TO THE GOOGLE DEEPMIND AND 
ECMWF ENSEMBLE MEANS THROUGH TAU 120 WITH LOW CONFIDENCE. INTENSITY 
GUIDANCE HAS SIGNIFICANTLY CHANGED THIS MODEL RUN, WITH NEARLY EVERY 
AVAILABLE RAPID INTENSIFICATION (RI) AID BEING TRIGGERED. PEAK 
INTENSITIES NOW RANGE FROM 85 KTS (HWRF) TO 135 KTS (RIDE) AT TAU 48. 
THE JTWC INTENSITY FORECAST IS PLACED NEAR THE HAFS-A (WHICH CLOSELY 
ALIGNS WITH THE RI MODELS) THROUGH TAU 48, THEN NEAR THE MULTI-MODEL 
CONSENSUS THROUGH TAU 120. CONFIDENCE IN THE INTENSITY FORECAST 
REMAINS LOW DUE TO THE HIGH UNCERTAINTY IN THE TRACK AND INHERENT 
UNCERTAINTIES REGARDING RI.

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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