Tropical Storm DOLPHIN Advisory Fri May 15

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (DOLPHIN) WARNING NR 31//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 07W (DOLPHIN), LOCATED APPROXIMATELY 384 NM EAST-
SOUTHEAST OF ANDERSEN AFB, GUAM HAS TRACKED WEST-NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS TIGHTLY CURVED BANDING WRAPPING INTO THE LOW
LEVEL CIRCULATION CENTER (LLCC) OBSCURED BY FLARING CENTRAL
CONVECTION. THE WATER VAPOR LOOP HAS SHOWN A STRUGGLING CONVECTIVE
SIGNATURE THAT HAS BEEN PULLING IN DRY AIR FROM THE WEST. A 130638Z
SSMIS 91GHZ MICROWAVE IMAGE SHOWS DEEP CONVECTIVE BANDING ALONG THE
NORTHERN PERIPHERY WITH SHALLOW BANDING ALONG THE SOUTHERN PERIPHERY
AND A DEVELOPING MICROWAVE EYE FEATURE. THE INITIAL POSITION IS
BASED ON THE TIGHTLY WOUND LLCC IN THE MSI LOOP AND THE MICROWAVE
IMAGE WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS HELD AT 90
KNOTS BASED ON CONSENSUS CURRENT INTENSITY ESTIMATES FROM PGTW AND
KNES. UPPER LEVEL ANALYSIS INDICATES TYPHOON DOLPHIN REMAINS IN AN
AREA OF MODERATE (15-20 KNOT) SOUTHERLY VERTICAL WIND SHEAR (VWS)
PARTIALLY OFFSET BY EXCELLENT RADIAL OUTFLOW WITH A POLEWARD BIAS.
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 TO 12 HOURS, AN UPPER LEVEL TROUGH PASSING TO
THE NORTH WILL CAUSE A BREAK IN THE STR, MODIFYING AND SLIGHTLY
SHIFTING TY 07W ON A 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 AND REORIENT TO THE EAST ALLOWING TYPHOON 07W TO
TURN POLEWARD. AS THE SYSTEM BEGINS TO ROUND THE STR AXIS, TY
DOLPHIN WILL GAIN AN INCREASED POLEWARD OUTFLOW CHANNEL, ASSOCIATED
WITH THE MID-LATITUDE WESTERLIES, LEADING TO A MAXIMUM INTENSITY OF
130 KNOTS BY TAU 72.
   C. IN THE EXTENDED TAUS, TY 07W WILL CONTINUE TO ROUND THE STR
AXIS AND BEGIN ITS WEAKENING TREND AS IT GAINS LATITUDE WHERE VWS
INCREASES AND SEA SURFACE TEMPERATURES DECREASE. DYNAMIC MODEL
GUIDANCE REMAINS IN GOOD AGREEMENT AND MOSTLY UNCHANGED FROM THE
PREVIOUS FORECAST. THE CURRENT JTWC TRACK FORECAST IS POSITIONED
CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.//
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