WDPN31 PGTW 291500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (GONI) WARNING NR
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 22W (GONI), LOCATED APPROXIMATELY 796 NM EAST OF MANILA,
PHILIPPINES, HAS TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL ENHANCED INFRARED SATELLITE IMAGERY
SHOWS A VERY COMPACT SYSTEM THAT CONTINUES TO RAPIDLY INTENSIFY,
WITH A NASCENT EYE FEATURE STARTING TO FORM JUST AFTER THE 1200Z
HOUR. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
TIMELY RECEIPT OF A 291200Z ASCAT-B BULLSEYE PASS, WHICH CLARIFIED
THE LLCC WHICH AT THAT TIME WAS STILL OBSCURED BY A CDO. THE INITIAL
INTENSITY IS SET WITH MODERATE CONFIDENCE AT 80 KNOTS, HEDGED HIGHER
THAN THE MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T4.0 (65
KNOTS) FROM PGTW, RJTD AND KNES, WHICH ARE LAGGING BEHIND THE
ADVANCED DVORAK TECHNIQUE ESTIMATE OF T4.7 (82 KNOTS) DUE TO THE
VERY COMPACT NATURE OF THE SYSTEM. TY 22W IS TRACKING WESTWARD UNDER
THE STEERING INFLUENCE OF A LARGE, DEEP-LAYER SUBTROPICAL RIDGE
(STR) WITH A NEW CENTER DEVELOPING JUST NORTHEAST OF TY 22W, PUSHING
IT BACK ONTO A WESTERLY COURSE A BIT FASTER THAN ANTICIPATED. TY
GONI CONTINUES MOVING THROUGH AN ENVIRONMENT THAT IS HIGHLY
FAVORABLE FOR ADDITIONAL RAPID INTENSIFICATION, WITH VERY WARM (30-
31 DEG CELSIUS) WATERS WITH HIGH OHC VALUES (GREATER THAN 150), LOW
(5-10 KNOTS) VWS AND ROBUST RADIAL OUTFLOW WITH THE POLEWARD OUTFLOW
BEING ENHANCED AS IT TAPS INTO A AN UPPER-LEVEL MID-LATITUDE TROUGH
PASSING BY TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE..
B. TY 22W WILL CONTINUE TRACKING GENERALLY WESTWARD THROUGH TAU
12 UNDER THE STEERING INFLUENCE OF THE STR CENTER LOCATED TO THE
NORTHEAST. BY TAU 24 THE SYSTEM WILL TURN ONTO A WEST-SOUTHWEST THEN
SOUTHWESTERLY TRACK AS THE PRIMARY STEERING MECHANISM SHIFTS TO THE
STR CENTER LOCATED OVER FAR SOUTHERN CHINA. BY TAU 72 THE SYSTEM
RESUMES A WEST TO SLIGHTLY WEST-NORTHWEST TRACK AS THE STEERING
PATTERN SHIFTS ONCE MORE TO THE STR CENTER TO THE NORTHEAST. TY 22W
IS FORECAST TO CONTINUE ITS RAPID INTENSIFICATION THROUGH TAU 36
UNDER VERY FAVORABLE CONDITIONS OF VERY WARM (31 DEG CELSIUS) SSTS
AND VERY HIGH (GREATER THAN 150) OHC, AND LOW (5 TO 10 KNOTS) VWS,
PEAKING AT 130 KNOTS AT TAU 48. INCREASING VWS IN CONJUNCTION WITH
WEAKER AND LESS DIVERGENT OUTFLOW ALOFT WILL COMBINE TO BEGIN A
STEADY WEAKENING TREND WITH THE SYSTEM WEAKENING TO 115 KNOTS BY TAU
72. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE NOTABLE
EXCEPTION OF NAVGEM, WHICH CONTINUES ITS TREND OF BEING WELL NORTH
OF THE REMAINDER OF THE GUIDANCE PACKAGE. WHEN DISCOUNTING NAVGEM,
THE SPREAD AT TAU 72 IS JUST 80 NM, INCREASING TO 130 NM IF NAVGEM
IS INCLUDED. THE JTWC FORECAST TRACK LIES ALONG THE NORTHERN SIDE OF
THE GUIDANCE ENVELOPE THROUGH TAU 72 WITH HIGH CONFIDENCE. INTENSITY
GUIDANCE CONTINUES TO STRONGLY INDICATE EXTREMELY RAPID
INTENSIFICATION AND THE JTWC FORECAST LIES ABOVE THE MAJORITY OF THE
INTENSITY CONSENSUS, CLOSE THE HWRF SOLUTION WITH HIGH CONFIDENCE.
C. BEYOND TAU 72, THE SYSTEM WILL TURN TOWARDS THE WEST-NORTHWEST
IN RESPONSE TO A SLIGHT WEAKENING IN THE STR, WITH LANDFALL IN
CENTRAL LUZON EXPECTED AROUND TAU 84 AS A SIGNIFICANT TROPICAL
CYCLONE. AFTER LANDFALL AND TRANSIT ACROSS THE MOUNTAINOUS TERRAIN
OF CENTRAL LUZON, THE SYSTEM WILL REEMERGE INTO THE SOUTH CHINA SEA
PRIOR TO TAU 96, ALBEIT AS A SIGNIFICANTLY WEAKENED TYPHOON DUE TO
COMBINED EFFECTS OF TERRAIN INTERACTION, INCREASED VWS AND
ENTRAINMENT OF COOLER AND DRIER AIR FROM THE NORTHEAST. THROUGH TAU
120, THE SYSTEM WILL CONTINUE TO WEAKEN UNDER THE INFLUENCE OF
MODERATE VWS AND CONTINUED ENTRAINMENT OF DRY MID-LEVEL AIR. DYNAMIC
MODEL GUIDANCE REMAINS IN GOOD OVERALL AGREEMENT THOUGH THE END OF
THE FORECAST WITH A CROSS-TRACK SPREAD OF 150 NM AT TAU 120.
HOWEVER, THE MODELS CONTINUE TO SHOW A FAIRLY LARGE AMOUNT OF ALONG-
TRACK SPREAD AFTER TAU 96, AND THE JTWC FORECAST TRACK LIES ALONG
THE NORTHERN EDGE OF THE MODEL GUIDANCE AND SLIGHTLY SLOWER THAN THE
MULTI-MODEL CONSENSUS WITH OVERALL LOW CONFIDENCE DUE TO THE
INCREASING ALONG-TRACK SPREAD.//
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