WDPN31 PGTW 230900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (GONI) WARNING NR 38//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 16W (GONI), LOCATED APPROXIMATELY 281 NM WEST-
SOUTHWEST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED AT 06 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
SHOWS CONVECTION HAS DEEPENED AROUND A NEW, LARGER 23-NM EYE. THE
INITIAL POSITION IS BASED ON THE EYE FEATURE IN THE MSI LOOP AND
SUPPORTED BY RJTD RADAR. THE INITIAL INTENSITY OF 90 KNOTS IS BASED
ON DVORAK ESTIMATES FROM PGTW AND RJTD AND REFLECTS THE DEEPENED
STATE OF THE CYCLONE. ANIMATED WATER VAPOR IMAGERY SHOWS IMPROVED
POLEWARD OUTFLOW INTO THE MID-LATITUDE WESTERLIES; THIS, IN ADDITION
TO THE EXISTING ROBUST EQUATORWARD OUTFLOW HAVE ENHANCED THE
CONVECTION. ADDITIONALLY, NORTHERLY VERTICAL WIND SHEAR REMAINS LIGHT
AT 5-10 KNOTS. TY 16W IS TRACKING UNDER THE STEERING INFLUENCE OF A
BUILDING NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST. SSTS ARE ALSO
VERY FAVORABLE AT 29 DEGREES CELSIUS.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY 16W WILL MOVE NORTHEASTWARD, STEERED BY THE BUILDING NER.
VWS IS FORECAST TO REMAIN LIGHT UNTIL TAU 24. ADDITIONALLY,
ALONG-TRACK SSTS, ALIGNED WITH THE WARM KUROSHIO CURRENT, WILL
PROMOTE FURTHER INTENSIFICATION. AFTERWARDS, THE FORECAST TRACK WILL
TURN MORE POLEWARD AS THE STR BUILDING TO THE EAST ASSUMES STEERING.
THE COMBINED EFFECTS OF INCREASING VWS. LAND INTERACTION WITH KYUSHU,
FOLLOWED BY COOLER WATERS OF THE SEA OF JAPAN WILL CAUSE GRADUAL THEN
RAPID WEAKENING. BY TAU 48, TY 16W WILL BEGIN EXTRA-TROPICAL
TRANSITION (ETT).
C. BEYOND TAU 72, TY GONI WILL TURN NORTH-NORTHWESTWARD AS THE STR
FURTHER BUILDS TO THE NORTH AND EAST. GONI WILL COMPLETE ETT
BY TAU 96 AS IT IS MAKES LANDFALL INTO THE RUGGED NORTHERN MOUNTAINS
OF NORTH KOREA. DYNAMIC GUIDANCE IS IN TIGHT AGREEMENT UP TO TAU 48
THEN SPREADS WITH VARYING DEGREES OF A NORTHWESTWARD TURN. AN OVERALL
GOOD AGREEMENT AMONG THE NUMERICAL GUIDANCE MEMBERS GIVES HIGH
CONFIDENCE TO THE JTWC FORECAST.//
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