Tropical Storm KALMAEGI Advisory Sun Sep 14

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (KALMAEGI) WARNING NR 16//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 15W (KALMAEGI), LOCATED APPROXIMATELY 203 NM NORTH-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD
AT 18 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY (EIR) SHOWS THE CENTRAL DENSE OVERCAST FEATURE AND
DEEP CONVECTIVE BANDING HAS WARMED AND STARTED TO DECREASE IN SIZE
AND SYMMETRY AS THE SYSTEM HAS MADE LANDFALL ACROSS NORTHERN LUZON.
A 141132Z SSMIS MICROWAVE IMAGE SHOWS THE LOW LEVEL CIRCULATION
CENTER (LLCC) HAS STARTED TO BECOME POORLY DEFINED WHILE THE TIGHTLY
CURVED BANDING PREVIOUSLY OBSERVED HAS BECOME FRAGMENTED. THERE IS
NOW ONLY FAIR CONFIDENCE IN THE INITIAL POSITION AND TRACK MOTION
DUE TO THE LLCC NOW BEING OVERLAND AND POORLY DEFINED. THE INITIAL
INTENSITY REMAINS ASSESSED AT 70 KNOTS BASED ON DVORAK INTENSITY
ESTIMATES THAT RANGE FROM 65 TO 77 KNOTS, WHILE A PREVIOUS 140845Z
SSMIS SHOWED IMPROVED STRUCTURE AS A DEVELOPING EYEWALL FEATURE WAS
OBSERVED JUST PRIOR TO LANDFALL. UPPER-LEVEL ANALYSIS REVEALS AN
UNCHANGED ENVIRONMENT CHARACTERIZED BY MODERATE (15 TO 25 KNOTS)
NORTHEASTERLY VERTICAL WIND SHEAR (VWS) THAT CONTINUES TO HAMPER THE
SYSTEM WHILE STRONG EQUATORWARD OUTFLOW AND THE MOTION OF THE SYSTEM
OFFSETS THE NEGATIVE EFFECTS OF THE VWS. TY 15W IS CURRENTLY
TRACKING ALONG THE SOUTHERN PERIPHERY OF AN EAST-WEST ORIENTED
SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH OF THE SYSTEM.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 15W IS FORECAST TO ACCELERATE WEST-NORTHWESTWARD UNDER THE
STEERING INFLUENCE OF THE STRONG STR THROUGH TAU 72. THE SYSTEM WILL
CONTINUE TO SLIGHTLY WEAKEN BEFORE RE-EMERGING ACROSS THE SOUTH
CHINA SEA (SCS) WERE RE-INTENSIFICATION IS EXPECTED DUE TO FAVORABLE
ENVIRONMENTAL CONDITIONS IN THE SCS. NEAR TAU 48, TY 15W IS FORECAST
TO WEAKEN AGAIN AS IT APPROACHES AND DRAGS ACROSS THE SOUTHERN COAST
OF CHINA.
   C. IN THE EXTENDED TAUS, TY 15W IS EXPECTED TO MAINTAIN A
PREDOMINANTLY WESTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST
PERIOD AS THE STR REMAINS ENTRENCHED TO THE NORTH. FURTHER WEAKENING
IS EXPECTED AS THE SYSTEM TRACKS WELL INLAND WITH DISSIPATION
EXPECTED BY TAU 96. DYNAMIC MODEL GUIDANCE (INCLUDING THE MODEL
ENSEMBLES) IS IN VERY TIGHT AGREEMENT, THEREFORE, THERE IS HIGH
CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS POSITIONED CLOSE TO
THE MULTI-MODEL CONSENSUS.//
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