Tropical Storm DOLPHIN Advisory Thu May 14

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (DOLPHIN) WARNING NR 32//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 07W (DOLPHIN), LOCATED APPROXIMATELY 290 NM EAST-
SOUTHEAST OF ANDERSEN AFB, GUAM HAS TRACKED WEST-NORTHWESTWARD AT 16
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A SMALL CONVECTIVE CORE STRUCTURE WITH BROKEN
CONVECTIVE BANDING ALONG THE NORTHERN PERIPHERY. THE BD CURVE
ENHANCEMENT REVEALS TROCHOIDAL MOTION WITHIN THE CONVECTIVE CORE AS
IT CONTINUES TO FIGHT DRY AIR TO THE WEST. A 140856Z SSMIS 91GHZ
MICROWAVE IMAGE DEPICTS A COMPACT CORE SURROUNDING A MICROWAVE EYE
FEATURE WITH THE MOST INTENSE CONVECTION ALONG THE NORTHWESTERN
PERIPHERY. THE INITIAL POSITION IS BASED ON A NOTCH IN THE 141134Z
AMSU-B MICROWAVE IMAGE AND EXTRAPOLATED FROM THE MICROWAVE EYE
FEATURE IN THE SSMIS IMAGE WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY HAS BEEN INCREASED TO 95 KNOTS BASED ON THE IMPROVED
CONVECTIVE SIGNATURE AND SUPPORTED BY AN INCREASE IN THE PGTW AND
RJTD DVORAK INTENSITY ESTIMATES. UPPER LEVEL ANALYSIS INDICATES
TYPHOON DOLPHIN REMAINS IN AN AREA OF MODERATE (15-20 KNOT) VERTICAL
WIND SHEAR (VWS) OFFSET BY EXCELLENT RADIAL OUTFLOW THAT IS
SUSTAINING CONVECTION. TYPHOON 07W IS CURRENTLY TRACKING ALONG THE
SOUTHERN PERIPHERY OF AN ELONGATED SUBTROPICAL RIDGE (STR) TO THE
NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. OVER THE NEXT 06 HOURS, AN UPPER LEVEL TROUGH PASSING TO THE
NORTH WILL CAUSE A BREAK IN THE STR, SHIFTING TY 07W ON A MORE
NORTHWESTWARD TRAJECTORY. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO
REMAIN MOSTLY UNCHANGED, LEADING TO A GRADUAL INTENSIFICATION RATE.
AFTER TAU 48, THE STEERING STR IS EXPECTED TO REBUILD TO THE
NORTHEAST ALLOWING TYPHOON 07W TO BEGIN THE TURN POLEWARD. TY
DOLPHIN WILL GAIN AN INCREASED POLEWARD OUTFLOW CHANNEL FROM THE MID-
LATITUDE WESTERLIES AS IT ROUNDS THE STR AXIS, ALLOWING IT TO
ACHIEVE ITS MAXIMUM INTENSITY.
   C. BEYOND TAU 72, TY DOLPHIN WILL ACCELERATE NORTHEASTWARD AFTER
IT ROUNDS THE STR AXIS. CONCURRENTLY, TY 07W WILL BEGIN ITS
WEAKENING TREND AS IT GAINS LATITUDE WHERE VWS INCREASES (25-35
KNOT) AND SEA SURFACE TEMPERATURES DROP BELOW 27 CELSIUS. BY THE END
OF THE FORECAST PERIOD, TY 07W WILL BEGIN TO EMBED WITHIN THE MID-
LATITUDE WESTERLIES AHEAD OF A SHORTWAVE TROUGH AND START EXTRA-
TROPICAL TRANSITION. DYNAMIC MODEL GUIDANCE CONTINUES TO REMAIN
CONSISTENT ON A TRACK BETWEEN GUAM AND SAIPAN. THE CURRENT JTWC
TRACK FORECAST IS POSITIONED JUST SOUTH OF THE MULTI-MODEL CONSENSUS
WITH HIGH CONFIDENCE.//
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