Tropical Storm DOLPHIN Advisory Sat May 16

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 07W (DOLPHIN) WARNING NR
40//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 07W DOLPHIN LOCATED APPROXIMATELY 500 NM
SOUTH OF IWO TO, JAPAN, HAS TRACKED NORTHWESTWARD AT 11 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY SHOWS THE SYSTEM HAS MAINTAINED A HIGHLY SYMMETRICAL 20 NM
EYE AS DEEP CONVECTIVE BANDS WRAPPED TIGHTER INTO THE LOW LEVEL
CIRCULATION CENTER. THE INITIAL POSITION IS BASED ON THE EYE FEATURE
IN THE EIR LOOP, WHICH IS ALSO EVIDENT ON A 16104Z 91 GHZ SSMIS
MICROWAVE PASS, WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 135
KNOTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM
PGTW, KNES, AND RJTD. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS
APPROACHING THE RIDGE AXIS AND REMAINS IN A LOW VERTICAL WIND SHEAR
(VWS) AREA. ADDITIONALLY, EXCELLENT RADIAL OUTFLOW, AS EVIDENT ON
ANIMATED WATER VAPOR IMAGERY, CONTINUES TO PROVIDE HIGHLY-EFFICIENT
VENTILATION TO THE CONVECTION. THE CYCLONE IS CURRENTLY TRACKING
ALONG THE SOUTHWEST PERIPHERY OF A DEEP LAYERED SUBTROPICAL RIDGE
(STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. STY 07W WILL CONTINUE TO TRACK NORTHWESTWARD OVER THE NEXT
12 HOURS UNDER THE INFLUENCE OF THE STR. AFTERWARDS, IT WILL ROUND
THE WESTERN EDGE OF THE STR AND CROSS INTO THE POLEWARD SIDE OF THE
RIDGE AXIS AND BEGIN TO ACCELERATE NORTHEASTWARD. CONTINUED FAVORABLE
UPPER LEVEL ENVIRONMENT, IN ADDITION TO WARM SEA SURFACE TEMPERATURES
(SSTS) AND INCREASED POLEWARD OUTFLOW CONCURRENT WITH THE SYSTEMS
INITIAL EXPOSURE TO THE STRONG MID-LATITUDE WESTERLIES, WILL FUEL
FURTHER INTENSIFICATION, PEAKING AT 145 KNOTS BETWEEN TAU 24-36.
AFTERWARDS, INCREASING VWS AND COOLING SSTS WILL BEGIN TO ERODE THE
SYSTEM. BY TAU 72, STY 07W WILL COMMENCE EXTRA-TROPICAL TRANSITION
(ETT) AS IT GETS EMBEDDED IN THE COLD BAROCLINIC AIR MASS.
   C. IN THE EXTENDED TAUS, STY DOLPHIN WILL CONTINUE TO ACCELERATE
NORTHEASTWARD AND DEEPER INTO THE BAROCLINIC ZONE. HIGH VWS, COOLING
SSTS, AND THE INFLUX OF COLD DRY AIR WILL GRADUALLY ERODE THE
SYSTEM. BY THE END OF THE FORECAST, THE SYSTEM WILL COMPLETE ETT AND
TRANSFORM INTO A STORM-FORCE COLD CORE LOW. DYNAMIC MODEL GUIDANCE
REMAINS IN VERY TIGHT AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC
TRACK FORECAST WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS.//
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