Tropical Storm NANGKA Advisory 05 Ιουλ.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (NANGKA) WARNING NR
06//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 11W (NANGKA), LOCATED APPROXIMATELY 202 NM
EAST OF ENEWETAK, HAS TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX
HOURS. THE CURRENT POSITION IS BASED ON A 041732Z PGTW SATELLITE FIX
AND A 041816Z GPM PASS. THE INTENSITY OF 50 KNOTS IS SET SLIGHTLY
HIGHER THAN MULTI-AGENCY DVORAK INTENSITY ESTIMATES BASED ON AN
EARLIER ASCAT PASS AND RECENT AUTOMATED SATELLITE INTENSITY
CONSENSUS DATA FROM CIMSS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS
DEEP CONVECTION FLARING NEAR THE CENTER OF A COMPACT LOW LEVEL
CIRCULATION CENTER EVIDENT IN THE 041816Z GPM PASS. TS 11W LIES IN
AN AREA OF LOW VERTICAL WIND SHEAR AND IMPROVING UPPER LEVEL
OUTFLOW. THE SYSTEM IS TRACKING WESTWARD ALONG THE SOUTHERN
PERIPHERY OF A SUBTROPICAL STEERING RIDGE TO THE NORTH.
3. FORECAST REASONING.
   A. THE FORECAST TRACK HAS BEEN SHIFTED SLIGHTLY EQUATORWARD FROM
THE PREVIOUS WARNING AND NEAR-TERM FORECAST INTENSITIES HAVE BEEN
LOWERED BY A FEW KNOTS. HOWEVER, THERE IS NO MAJOR CHANGE TO
FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 11W WILL CONTINUE TRACKING ALONG THE PERIPHERY OF THE
CURRENT SUBTROPICAL STEERING RIDGE THROUGH THE NEXT 72 HOURS,
GRADUALLY TRENDING FROM A GENERALLY WESTWARD TRACK IN THE NEAR-TERM
TOWARD A NORTHWESTWARD TRACK AS THE STEERING RIDGE REORIENTS. LOW
VERTICAL WIND SHEAR AND FAVORABLE OUTFLOW WILL ALLOW THE SYSTEM TO
STEADILY INTENSIFY DURING THIS PERIOD. DYNAMIC MODEL GUIDANCE IS IN
FAIR AGREEMENT REGARDING THE FORECAST TRACK, WITH SOME SPREAD NOTED
IN THE ORIENTATION OF THE TRACK BETWEEN MORE WESTWARD AND MORE
NORTHWESTWARD. THE CURRENT TRACK FORECAST LIES CLOSE TO THE MULTI-
MODEL CONSENSUS, WHICH HAS SHIFTED SLIGHTLY EQUATORWARD FROM THE
PREVIOUS RUN.
   C. IN THE EXTENDED FORECAST PERIOD, TS 11W IS EXPECTED TO
CONTINUE TRACKING GENERALLY NORTHWESTWARD ALONG THE SUBTROPICAL
RIDGE PERIPHERY. INTENSIFICATION SHOULD CONTINUE AS ENVIRONMENTAL
CONDITIONS REMAIN MOSTLY FAVORABLE, ALTHOUGH RESTRICTED POLEWARD
OUTFLOW MAY LIMIT THE INTENSIFICATION RATE AS REFLECTED IN THE
CURRENT FORECAST. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT IN THE
EXTENDED RANGE, LENDING HIGH CONFIDENCE TO THE CURRENT TRACK
FORECAST.//
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