Tropical Storm HAIMA Advisory Di, 18.10.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (HAIMA) WARNING NR 14//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
  TYPHOON 25W (HAIMA), LOCATED APPROXIMATELY 644 NM EAST OF MANILA,
PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS A TIGHTLY SPIRALED SYSTEM WITH A 15 NM WELL-DEFINED EYE
FEATURE GIVING HIGH CONFIDENCE TO THE INITIAL POSITION. A PREVIOUS
171638Z AMSR2 89 GHZ IMAGE SHOWED AN OUTER RING OF DEEP CONVECTION
SURROUNDING THE INNER EYE SUGGESTING AN EYEWALL REPLACEMENT CYCLE
(ERC) WAS UNDERWAY. HOWEVER, NO RECENT MICROWAVE DATA IS AVAILABLE
TO CONFIRM EYEWALL CONTRACTION AND MSI OVER THE LAST SIX HOURS
INDICATES EYEWALL EXPANSION, REVERSING THE ERC TREND. THE INITIAL
INTENSITY IS ASSESSED AT 120 KNOTS AND IS BASED ON CURRENT INTENSITY
DVORAK ESTIMATES RANGING FROM T6.0 TO T6.5 (115 TO 127 KNOTS). UPPER-
LEVEL ANALYSIS SHOW EXCELLENT RADIAL OUTFLOW WITH VERY LOW VERTICAL
WIND SHEAR. SEA SURFACE TEMPERATURES ARE ALSO VERY FAVORABLE NEAR 30
CELSIUS. CURRENTLY TY HAIMA IS TRACKING NORTHWEST ALONG THE
PERIPHERY ON A DEEP LAYERED SUBTROPICAL RIDGE POSITIONED TO THE
NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
   B. TY HAIMA WILL CONTINUE TO TRACK NORTHWESTWARD ALONG THE
SUBTROPICAL RIDGE AS IT BUILDS EXTENDING WESTWARD. THE INTENSITY IS
EXPECTED TO PULSATE AROUND 120 KNOTS OVER THE NEXT 12 TO 24 HOURS AS
THE SECONDARY EYE FEATURE OBSERVED IN THE AFOREMENTIONED MICROWAVE
IMAGE REORGANIZES WITH THE POTENTIAL FOR ERC IN THE NEAR FUTURE.
ANOTHER PERIOD OF SLIGHT INTENSIFICATION IS LIKELY AFTER TAU 24 AS
FAVORABLE CONDITIONS PERSIST, REACHING A PEAK INTENSITY OF 125
KNOTS. LAND INTERACTION WITH THE NORTHERN COAST OF LUZON IS EXPECTED
NEAR TAU 42 SETTING IN MOTION A WEAKENING TREND EXPECTED TO CONTINUE
THROUGH THE REMAINDER OF THE FORECAST PERIOD.
   C. BEYOND TAU 72 TY HAIMA WILL BEGIN TO ROUND THE STEERING RIDGE
AXIS SHIFTING FROM A NORTHWESTWARD TRACK TO A NORTH-NORTHEASTWARD
TRACK. AROUND TAU 90 THE SYSTEM IS EXPECTED TO MAKE LANDFALL EAST OF
HONG KONG AND TRACK INLAND AS IT COMPLETES ITS TRACK SHIFT.
AVAILABLE MODEL GUIDANCE SHOWS VERY GOOD AGREEMENT THROUGH TAU 72.
MODEL SOLUTIONS BEYOND TAU 72 SHOW SOME DIVERGENCE IN TRACK MOTION
AS THE SYSTEM ROUNDS THE RIDGE AXIS OVER LAND, BUT ALL AVAILABLE
SOLUTIONS ARE SHOWING A NORTHWARD CURVE AROUND THE STEERING RIDGE.
DUE TO THE GOOD AGREEMENT IN MODELS UP TO TAU 72 AND RELATIVELY GOOD
AGREEMENT AS IT MAKES LANDFALL, THERE IS OVERALL HIGH CONFIDENCE IN
THE FORECAST TRACK.//
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