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JTWC/04W/#11/04-11 12Z Prognostic Reasoning
WDPN31 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (SINLAKU) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 9.0N 151.1E
INITIAL INTENSITY: 85 KTS
GEOGRAPHIC REFERENCE: 465 NM SOUTHEAST OF NAVSTA GUAM
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 30 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
CONSOLIDATION OF DEEP CONVECTIVE BANDING SPIRALING INTO A CENTRAL
DENSE OVERCAST (CDO) FEATURE THAT IS OBSCURING THE LOW-LEVEL
CIRCULATION CENTER (LLCC) OF TYPHOON (TY) 04W (SINLAKU). THE INITIAL
POSITION IS DETERMINED WITH HIGH FIDELITY, PINPOINTED BY THE CENTRAL
CONVECTIVE CONVERGENCE, APPARENT IN THE SHORTWAVE INFRARED IMAGERY
LOOP, SUPPORTED BY THE EXTRAPOLATION FROM A 110809Z SENTINEL-1C SAR
WIND SPEED PRODUCT. THE INITIAL INTENSITY OF 85 KTS IS ALSO ASSESSED
WITH HIGH CONFIDENCE, SUPPORTED BY STRONG AGREEMENT AMONG OBJECTIVE
INTENSITY AIDS AND AGENCY DVORAK ESTIMATES, ADDITIONALLY CORROBORATED
BY THE AFOREMENTIONED SAR PASS SHOWING PEAK WIND SPEEDS OF 83-86 KTS.
A COMPREHENSIVE ENVIRONMENTAL DIAGNOSIS REVEALS EXCEPTIONALLY
CONDUCIVE CONDITIONS FOR INTENSIFICATION, CHARACTERIZED BY HIGH
OCEANIC HEAT CONTENT WITH SEA SURFACE TEMPERATURES OF 28-29 C, A MOIST
TROPOSPHERIC COLUMN, NEGLIGIBLE VERTICAL WIND SHEAR AT 5-10 KTS, AND
ROBUST, RADIAL UPPER-LEVEL OUTFLOW. THIS EFFICIENT VENTILATION IS
FURTHER AUGMENTED BY THE PRESENCE OF AN UPPER-LEVEL ANTICYCLONE TO THE
NORTHEAST AND A NEAR-EQUATORIAL RIDGE TO THE EAST.
INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK
CURRENT STEERING MECHANISM: WEAK STEERING ENVIRONMENT WITH A
NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST AND A SUBTROPICAL
RIDGE (STR) TO THE NORTHWEST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T5.0 - 90 KTS
RJTD: T5.0 - 90 KTS
RCTP: T5.0 - 90 KTS
KNES: T5.0 - 90 KTS
CIMSS ADT: 82 KTS AT 111130Z
CIMSS AIDT: 82 KTS AT 111130Z
CIMSS D-MINT: 80 KTS AT 110740Z
CIMSS D-PRINT: 74 KTS AT 111230Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
VWS: 5-10 KTS
SST: 28-29 CELSIUS
OUTFLOW: STRONG RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: HIGH
INITIAL WIND RADII: LOW
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TY SINLAKU CONTINUES TO SLOWLY TRACK
NORTHWESTWARD, DRIVEN BY A GENERALLY WEAK AMBIENT STEERING FLOW. MODEL
DATA INDICATES THAT A NORTHWARD EXTENSION OF THE NEAR-EQUATORIAL RIDGE
(NER) IS PROGGED TO BUILD AND BECOME THE PRIMARY STEERING MECHANISM.
CONSEQUENTLY, TY 04W IS FORECAST TO ACCELERATE ON A GENERALLY
NORTHWESTWARD TRAJECTORY TOWARD THE SOUTHERN MARIANA ISLANDS. THE
PERSISTENCE OF A HIGHLY FAVORABLE ATMOSPHERIC AND OCEANIC REGIME IS
EXPECTED TO FUEL A PERIOD OF RAPID INTENSIFICATION, WITH A PEAK
INTENSITY OF 125 KTS PROJECTED AROUND TAU 48, PRIOR TO THE CLOSEST
POINT OF APPROACH TO THE ISLANDS. THE EXPANSIVE NATURE OF THE WIND
FIELD WILL LIKELY BRING GALE FORCE WINDS (34 KT WIND RADII) WITHIN
RANGE OF SOUTHERN MARIANAS BETWEEN TAUS 36 AND 48. AROUND TAU 72, TY
04W IS EXPECTED TO INITIATE RECURVATURE AROUND THE SOUTHWESTERN
PERIPHERY OF THE BUILDING RIDGE EXTENSION. A GRADUAL WEAKENING TREND
IS ANTICIPATED TO COMMENCE AT THAT JUNCTURE AS VERTICAL WIND SHEAR
BEGINS TO MODESTLY INCREASE.
MODEL DISCUSSION: NUMERICAL MODEL PREDICTION GUIDANCE IS IN FAIR
AGREEMENT ON THE GENERAL STEERING PATTERN AND THE ULTIMATE
RECURVATURE SCENARIO. TRACK MODEL GUIDANCE HAS IMPROVED AGAIN SINCE
THE LAST WARNING, AS WITNESSED BY A CROSS-TRACK SPREAD OF LESS THAN 70
NM AMONG THE MULTI-MODEL CONSENSUS MEMBERS AND AROUND THE TIME OF
CPA TO THE ISLAND CHAIN. THE INDIVIDUAL TRACKERS CONVERGE WITHIN AN
AREA BETWEEN THE ISLANDS OF GUAM AND TINIAN, WITH THE TRACK CONSENSUS
MEAN NOW POSITIONED JUST NORTHWEST OF GUAM. UNCERTAINTY IN THE LONG
TERM TRACK FORECAST IS STILL HIGH, AND WILL DEPEND HEAVILY ON THE
EVOLUTION OF THE DEEP-LAYER STEERING PATTERN. CURRENTLY ALL MODELS
FAVOR THE RECURVATURE SCENARIO, HOWEVER, IF THE SUBTROPICAL RIDGE
(STR) TO THE WEST-NORTHWEST DOES NOT RETREAT WESTWARD AND TOWARD THE
SOUTH CHINA SEA, TY 04W MAY YET AGAIN FIND ITSELF WITHIN A COMPETING
STEERING ENVIRONMENT. AS SUCH, THE STR WOULD PROVIDE A WESTWARD
COMPONENT, WHILE THE EXTENSION OF THE NER TO THE SOUTHEAST WOULD STEER
THE SYSTEM NORTHWARD AND TOWARDS RECURVATURE. THEREFORE, LONG-TERM
TRACK FORECAST IS ASSESSED WITH LOW CONFIDENCE, BUT IS LAID CLOSE TO
THE MULTI-MODEL CONSENSUS GUIDANCE. REGARDING INTENSITY, THE OFFICIAL
FORECAST IS ALIGNED CLOSELY WITH THE HAFS SOLUTION AND IS SET SLIGHTLY
ABOVE THE MULTI-MODEL MEAN, WITH MEDIUM CONFIDENCE. THE HAFS
PROJECTION OF A 120-125 KTS PEAK AT TAU 48 IS CONSISTENT WITH THE
OFFICIAL JTWC FORECAST. GLOBAL DETERMINISTIC AND STATISTICAL-DYNAMICAL
MODELS STILL OFFER A MORE CONSERVATIVE PEAK INTENSITY IN THE 100-115
KTS RANGE. SEVERAL RAPID INTENSIFICATION AIDS INDICATE THE POTENTIAL
FOR A MAXIMUM INTENSITY REACHING 140 KTS.
FORECAST CONFIDENCE:
TRACK 00-72 HR: MEDIUM
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
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楼主: ygsj24
发表于 2026-4-11 20:37
