Tapah(18W) becoming extratropical and accelerating. Invest 96A: upgraded to medium

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WESTERN NORTH PACIFIC

TS TAPAH(18W)
As of 06:00 UTC Sep 22, 2019:
Location: 32.7°N 127.9°E
Maximum Winds: 55 kt ( 100km/h)
Gusts: 70 kt ( 130km/h)
Minimum Central Pressure: 979 mb
WDPN31 PGTW 220900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W (TAPAH) WARNING NR
014//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 18W (TAPAH), LOCATED APPROXIMATELY 94 NM WEST-
SOUTHWEST OF SASEBO, JAPAN, HAS TRACKED NORTHEASTWARD AT 22 KNOTS
OVER THE PAST SIX HOURS. TS 18W HAS COMMENCED EXTRA-TROPICAL
TRANSITION (ETT) AND IS ACCELERATING NORTHEASTWARD WITHIN THE
MIDLATITUDE SOUTHWESTERLIES. ADDITIONALLY, THE SYSTEM HAS A WEAK
FRONTAL STRUCTURE AS EVIDENCED IN SATELLITE IMAGERY AND THE 22/00Z
1000-500MB THICKNESS ANALYSIS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A BROAD, EXPOSED LOW-LEVEL CIRCULATION (LLCC) WITH
DEEP CONVECTION SHEARED OVER THE NORTH AND NORTHEAST QUADRANTS DUE
TO STRONG (30-35 KNOT) SOUTHERLY VERTICAL WIND SHEAR (VWS). ALTHOUGH
BROAD, THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION DUE TO THE
EXPOSED NATURE OF THE LLCC AND RJTD RADAR FIXES. A 220508Z AMSR2
89GHZ COLOR COMPOSITE IMAGE SHOWS A DEFINED LLCC WITH DEEP
CONVECTIVE BANDING PERSISTING OVER THE NORTH QUADRANT. SURFACE
OBSERVATIONS HAVE INCREASED ALONG THE NORTHWEST COAST OF KYUSHU
ISLAND WITH 40-45 KNOT WIND GUSTS REPORTED. THE INITIAL INTENSITY OF
55 KNOTS IS BASED ON A DVORAK CURRENT INTENSITY ESTIMATE OF 3.5 (55
KNOTS) FROM PGTW. ENVIRONMENTAL CONDITIONS ARE GRADUALLY DEGRADING
WITH THE INCREASING VWS AND SLIGHTLY COOLER SST, HOWEVER, POLEWARD
OUTFLOW REMAINS ROBUST. TS 18W IS TRACKING NORTHEASTWARD AS IT
RECURVES AROUND THE NORTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE
(STR) LOCATED TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 18W WILL CONTINUE TO RECURVE NORTHEASTWARD INTO THE SEA OF
JAPAN WITH INCREASING, HOSTILE VWS EXPECTED AND COOLER SST (LESS
THAN 24C). TS 18W WILL COMPLETE ETT BY TAU 24 AND CONTINUE TO
ACCELERATE NORTHEASTWARD TOWARD HOKKAIDO. THE SYSTEM IS FORECAST TO
REMAIN A STRONG COLD-CORE LOW WITH GALE-FORCE WINDS ANTICIPATED OVER
NORTHERN HONSHU. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
THROUGH TAU 36, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK.//
NNNN
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NORTH INDIAN

INVEST 96A
As of 06:00 UTC Sep 22, 2019:
Location: 20.0°N 68.8°E
Maximum Winds: 30 kt
Minimum Central Pressure: 1001 mb
ABIO10 PGTW 212300
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
   A. TROPICAL CYCLONE SUMMARY: NONE.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) AN AREA OF CONVECTION (INVEST 96A) PREVIOUSLY LOCATED NEAR
19.2N 70.2E, IS NOW LOCATED NEAR 19.2N 69.9E, APPROXIMATELY 167 NM
WEST OF MUMBAI, INDIA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
AND A 211901Z 89GHZ GMI IMAGE DEPICT A CONSOLIDATING LOW LEVEL
CIRCULATION WITH PERSISTENT DEEP CONVECTION. UPPER LEVEL ANALYSIS
REVEALS 96A IS MOVING INTO AN AREA OF MODERATE VERTICAL WIND SHEAR
(15-25 KNOTS) AND HAS VERY LITTLE OUTFLOW ALOFT. SEA SURFACE
TEMPERATURES REMAIN FAVORABLE AT 27-28 DEGREES CELSIUS. GLOBAL
MODELS ARE IN GOOD AGREEMENT THAT 96A WILL SLOWLY TRACK WESTWARD.
ADDITIONALLY, ECMWF SHOWS 96A REACHING SUSTAINED WINDS OF 35 KNOTS
WITHIN 48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20
TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1002
MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.