WDPN31 PGTW 270300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (NANMADOL) WARNING NR 18//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TYPHOON (TY) 14W (NANMADOL), LOCATED APPROXIMATELY 580 NM 
SOUTH-SOUTHWEST OF KADENA AB, OKINAWA, HAS TRACKED NORTHWESTWARD AT 
03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY SHOWS THAT LAND INTERACTION WITH LUZON HAS CAUSED THE EYE TO 
BECOME CLOUD-FILLED WHILE THE EYEWALL ALONG THE NORTHERN SEMICIRCLE 
HAS ERODED. A 262219Z SSMIS MICROWAVE IMAGE SHOWS THAT THE LOW LEVEL 
CIRCULATION CENTER IS JUST SEAWARD OF THE NORTHEASTERN TIP OF LUZON, 
WITH THE EASTERN HALF OF THE STORM REMAINING WELL ORGANIZED WITH 
ABUNDANT DEEP CONVECTION. ANIMATED WATER VAPOR IMAGERY CONFIRMS THE 
POLEWARD OUTFLOW CHANNEL IS STILL OPEN OVER THE NORTHEASTERN 
QUADRANT, AND OUTFLOW IN THE OTHER QUADRANTS REMAINS VIGOROUS. TY 
14W IS BEING NUDGED TO THE NORTHWEST BY THE WESTWARD EXTENSION OF 
THE NEAR EQUATORIAL RIDGE. 
3. FORECAST REASONING
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY. 
   B. THE NEAR EQUATORIAL RIDGE WILL BUILD OVER THE PHILIPPINE SEA 
DURING THE NEXT 72 HOURS AND REMAIN THE DOMINANT STEERING INFLUENCE. 
THE RIDGE WILL GUIDE TY 14W TOWARDS THE EAST COAST OF TAIWAN. ALONG-
TRACK ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR RE-INTENSIFICATION. 
VERTICAL WIND SHEAR, CURRENTLY ASSESSED AT JUST 08 KNOTS, WILL 
WEAKEN FURTHER OVER THE LUZON STRAIT, WHILE SEA SURFACE TEMPERATURES 
WILL AVERAGE 31 DEGREES CELSIUS. THUS, TY 14W WILL RE-INTENSIFY 
DURING THE NEXT 24 HOURS AS IT CLEARS THE LAND IMPEDIMENTS OF LUZON, 
THEN WEAKEN AGAIN AS IT APPROACHES TAIWAN. THE EFFECTS OF LAND 
INTERACTION WITH TAIWAN WILL BECOME EVIDENT BY TAU 36. 
   C. AFTER TAU 72, TY 14W WILL ENCOUNTER COMPETING STEERING 
INFLUENCES BETWEEN THE NEAR EQUATORIAL RIDGE AND AN UPPER LEVEL 
ANTICYCLONE SETTLING JUST WEST OF KYUSHU. ECMWF AND JGSM MOVE THE 
SYSTEM ACROSS THE TAIWAN STRAIT AND TO LANDFALL OVER EASTERN CHINA, 
WHILE THE REMAINDER OF THE TRACKERS KEEP TY 14W EAST OF TAIWAN. THE 
JTWC TRACK FORECAST STAYS CLOSE TO CONSENSUS, WHICH PRESENTS A GOOD 
MEAN BETWEEN THE DISPARATE MODEL SOLUTIONS. THE ENVIRONMENTAL 
CONDITIONS ALONG THE TRACK WILL REMAIN HIGHLY FAVORABLE FOR 
DEVELOPMENT, BUT LAND INTERACTION WITH TAIWAN WILL MITIGATE THOSE 
FACTORS.//
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