Tropical Storm DOLPHIN Advisory Wed May 13

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (DOLPHIN) WARNING NR 28//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 07W (DOLPHIN), LOCATED APPROXIMATELY 576 NM
EAST-SOUTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD
AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY (EIR) SHOWS THE SYSTEM HAS MAINTAINED A 10-NM EYE
AS CONVECTIVE BANDING DEEPENED AND WRAPPED TIGHTER INTO THE LOW LEVEL
CIRCULATION CENTER. THE INITIAL POSITION IS BASED ON THE EIR LOOP
WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 90 KNOTS IS BASED ON
CONGRUENT DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD. UPPER LEVEL
ANALYSIS SHOWS THE SYSTEM IS SOUTH OF THE RIDGE AXIS IN AN AREA OF
LOW VERTICAL WIND SHEAR AND GOOD RADIAL OUTFLOW WITH A STRONG
EQUATORWARD BIAS. THE CYCLONE IS TRACKING ALONG THE SOUTHEASTERN
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. IN THE NEAR TO MID-TERM, TY 07W WILL CONTINUE TO TRACK
GENERALLY WEST-NORTHWESTWARD UNDER THE INFLUENCE OF THE STR. THE
SYSTEM IS FORECAST TO CONTINUE STRENGTHENING AS FAVORABLE UPPER
LEVEL CONDITIONS, IN ADDITION TO WARM ALONG-TRACK SEA SURFACE
TEMPERATURES, PERSIST. BY TAU 72, THE SYSTEM WILL HAVE REACHED 120
KNOTS.
   C. IN THE EXTENDED TAUS, TY DOLPHIN WILL BEGIN TO ROUND THE BREAK
IN THE STR CAUSED BY A TRANSITORY MID-LATITUDE TROUGH DIGGING IN FROM
THE NORTHWEST AND PASSING THROUGH JAPAN. THIS POLEWARD TRACK WILL
EXPOSE THE CYCLONE TO INCREASED UPPER LEVEL WIND FLOW ASSOCIATED WITH
THE MID-LATITUDE WESTERLIES. THIS INITIAL EXPOSURE WILL ENHANCE THE
POLEWARD OUTFLOW AND TRIGGER RAPID INTENSIFICATION - REACHING SUPER
TYPHOON INTENSITY BY END OF FORECAST. DYNAMIC MODEL GUIDANCE REMAINS
IN VERY TIGHT AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC TRACK
FORECAST.//
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