
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MARIA) WARNING NR
18//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 10W (MARIA), LOCATED APPROXIMATELY 463 NM SOUTH OF
IWO TO, JAPAN, HAS TRACKED NORTHWESTWARD AT 02 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES
THAT TY 10W HAS FAILED TO RE-INTENSIFY MUCH SINCE THE PREVIOUS
ANALYSIS. MICROWAVE IMAGERY AT 062101Z INDICATED THAT THE EYEWALL
REPLACEMENT CYCLE (ERC) HAD COMPLETED, WITH A WELL DEFINED NEW OUTER
EYEWALL COMPLETELY REPLACING THE DISSIPATED INNER EYEWALL. NEAR-TERM
CONTRACTION OF THE EYE WAS EXPECTED WITH THE ASSOCIATED
INTENSIFICATION, BUT THE SYSTEM HAS MAINTAINED INTENSITY AT 125
KNOTS, THOUGH THIS ESTIMATE IS HEDGED HIGHER THAN BOTH AUTOMATED
DVORAK AND SUBJECTIVE DVORAK ANALYSES RESULTING IN T6.0 (115 KNOTS).
DEEP CONVECTION IS REFORMING AROUND THE ASSESSED CENTER, BUT IS
STRUGGLING TO PERSIST. THE INITIAL POSITION IS PLACED WITH MODERATE
CONFIDENCE BASED ON A CLOUD-FILLED EYE FEATURE EVIDENT IN THE MSI,
AND EXTRAPOLATION OF THE PREVIOUSLY MENTIONED MICROWAVE IMAGE.
ENVIRONMENTAL ANALYSIS INDICATES THAT TY 10W REMAINS IN A FAVORABLE
ENVIRONMENT, WITH MODERATE OUTFLOW, LOW VWS AND HIGH SSTS. A TUTT
CELL TO THE NORTHEAST IS TRACKING SLOWLY WESTWARD AND SATELLITE
DERIVED UPPER-LEVEL WIND VECTORS INDICATE THAT OUTFLOW IS BEGINNING
TO BE PULLED INTO THIS CELL, IMPROVING EXHAUST FOR THE SYSTEM. AT
THE SAME TIME, AN UPPER-LEVEL ANTICYCLONE HAS DEVELOPED TO THE
SOUTHEAST OF THE SYSTEM, AND IS ENABLING A BROAD AND WEAK
EQUATORWARD OUTFLOW CHANNEL. TY 10WÂ’S FORWARD MOTION HAS SLOWED
SIGNIFICANTLY OVER THE PAST SIX HOURS, AS A NORTH-SOUTH ORIENTED
EXTENSION OF THE STR CENTERED TO THE NORTHEAST HAS DEVELOPED TO THE
WEST OF THE SYSTEM, EFFECTIVELY PUTTING THE BRAKES ON FORWARD
TRANSLATION, LEADING TO A SLOW DRIFT TOWARDS THE NORTH-NORTHWEST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THE AFOREMENTIONED NORTH-SOUTH ORIENTED RIDGE, WHICH IS
CURRENTLY RESULTING IN A SLOW DRIFT NORTH-NORTHWESTWARD IS FORECAST
TO REMAIN IN PLACE THROUGH ABOUT TAU 12 TO 18, RESULTING IN A
CONTINUED SLOW MOVEMENT TO THE NORTH-NORTHWEST. BY TAU 24, THE RIDGE
WEAKENS AND RETREATS NORTHWARD, ALLOWING TY 10W TO TURN MORE WEST-
NORTHWESTWARD AND ACCELERATE, CONTINUING ALONG THIS GENERAL TRACK
THROUGH TAU 72 UNDER THE INFLUENCE OF AN EAST-WEST ORIENTED DEEP-
LAYER STR CENTERED TO THE NORTHEAST OVER CENTRAL HONSHU. DESPITE THE
QUASI-STATIONARY MOVEMENT OVER THE PAST SIX HOURS AND THE SLOW
MOVEMENT TO THE NORTHWEST, TY 10W REMAINS IN A FAVORABLE ENVIRONMENT
FOR NEAR-TERM INTENSIFICATION. SSTS AND OCEAN HEAT CONTENT VALUES
ARE VERY HIGH AND ARE PROVIDING AMPLE ENERGY TO SUPPORT THE SYSTEM.
THE TUTT CELL TO THE NORTHEAST IS SLOWLY DRIFTING WESTWARD AND WILL
SOON BE IN A FAVORABLE POSITION FOR TY 10W TO TAP INTO THIS OUTFLOW
CHANNEL. THIS COMBINED WITH CONTINUED LOW VWS (5-10 KNOTS) WILL
ALLOW FOR INTENSIFICATION TO 130 KNOTS BY TAU 12, MAINTAINING
THROUGH TAU 24. BEYOND TAU 24 AND THROUGH ABOUT TAU 48, TY 10W WILL
STEADILY WEAKEN AS THE TUTT MOVES OFF TO THE NORTH AND OUTFLOW
DECREASES. A SHORT PERIOD OF LESS RAPID WEAKENING IS EXPECTED
BETWEEN TAU 48 AND 72, AS TY 10W BRIEFLY TAPS INTO A WEAK POLEWARD
OUTFLOW CHANNEL AHEAD OF A MID-LATITUDE TROUGH PASSING TO THE NORTH
OF THE SYSTEM, THOUGH BY THIS POINT THE SYSTEM WILL BE MOVING OVER
COOLER WATERS AND WILL NOT INTENSIFY. NUMERICAL MODEL GUIDANCE IS IN
GOOD CROSS-TRACK AGREEMENT THROUGH TAU 72 WITH A SPREAD OF 98 NM AT
TAU 72 BETWEEN THE RIGHT OUTLIER (UKMO) AND THE LEFT OUTLIER (COAMPS-
TC). HOWEVER, ALONG-TRACK SPREAD HAS INCREASED BETWEEN TAU 0 AND TAU
72 DUE TO THE RECENT SLOWING IN FORWARD MOTION, LENDING DECREASED
CONFIDENCE IN THE STORM MOTION PORTION OF THE TRACK. OVERALL, THERE
REMAINS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.
C. AFTER TAU 72, TY 10W IS FORECAST TO CONTINUE TRACKING WEST-
NORTHWESTWARD AS THE STR TO THE NORTHEAST STRENGTHENS AND RIDGES
WESTWARD INTO CENTRAL CHINA, REMAINING THE DOMINANT STEERING
INFLUENCE. THE SYSTEM IS FORECAST TO TRANSIT SOUTH OF OKINAWA AND
MAKE LANDFALL AROUND TAU 108 ALONG THE EAST-CENTRAL COAST OF CHINA
SOUTH OF SHANGHAI. TY 10W IS FORECAST TO STEADILY WEAKEN FROM TAU 72
TO LANDFALL AND BEYOND, AS ENVIRONMENTAL CONDITIONS PROGRESSIVELY
DETERIORATE. THE SYSTEM WILL TRANSIT A COOL POOL OF WATER AS IT
APPROACHES THE RYUKUS, WHILE AT THE SAME TIME VWS INCREASES AND
OUTFLOW BECOMES CHOKED OFF UNDER THE INFLUENCE OF NORTHERLY FLOW AND
MASS CONVERGENCE. NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT
BEYOND TAU 72, WITH 145 NM SPREAD BETWEEN THE HWRF ON THE RIGHT AND
THE COAMPS-TC ON THE LEFT OF THE ENVELOPE AT TAU 96, INCREASING
FURTHER BY TAU 120 AS THE SYSTEM APPROACHES THE CHINESE COAST. THE
ECMWF SOLUTION REMAINS A LEADING INDICATOR AND CONTINUES TO BE ON
THE LEFT OR SOUTH EDGE OF GUIDANCE ENVELOPE. THE OFFICIAL TRACK IS
HEDGED SLIGHTLY SOUTH OF THE MULTI-MODEL CONSENSUS TOWARDS THE ECMWF
SOLUTION. ALONG-TRACK SPREAD DECREASES AFTER TAU 72 AND RESUMES
ALIGNMENT WITH THE PREVIOUS FORECAST. DUE TO THE TIGHTLY PACKED
NATURE OF THE AVAILABLE GUIDANCE, THERE REMAINS HIGH CONFIDENCE IN
THIS PORTION OF THE JTWC FORECAST TRACK.//
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