LEKIMA tracking west of Shanghai with strong winds but weakening. Krosa: update

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WESTERN NORTH PACIFIC

TY LEKIMA(10W)
As of 06:00 UTC Aug 10, 2019:
Location: 30.2°N 120.5°E
Maximum Winds: 65 kt ( 120km/h)
Gusts: 80 kt ( 150km/h)
Minimum Central Pressure: 962 mb
CATEGORY US: 1
WEAKENING
WDPN31 PGTW 100900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (LEKIMA) WARNING NR 26//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 10W (LEKIMA), LOCATED APPROXIMATELY 79 NM SOUTHWEST OF
SHANGHAI, CHINA, HAS TRACKED NORTH-NORTHWESTWARD AT 13 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A
RAPIDLY WEAKENING SYSTEM WITH LIMITED DEEP CONVECTION DISPLACED OVER
THE NORTHERN PERIPHERY. A 100526Z AMSR2 89GHZ IMAGE AND RADAR IMAGERY
INDICATE A DEFINED LOW-LEVEL CIRCULATION CENTER, THEREFORE, THERE IS
GOOD CONFIDENCE IN THE INITIAL POSITION. UPPER-LEVEL ANALYSIS REVEALS
LOW VERTICAL WIND SHEAR AND ROBUST POLEWARD OUTFLOW ENHANCED BY A
SHORTWAVE TROUGH TO THE NORTHWEST. THEREFORE, INTERACTION WITH LAND /
FRICTIONAL EFFECTS ARE THE PRIMARY WEAKENING MECHANISM. TY 10W IS
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE
(STR) POSITIONED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 10W IS FORECAST TO TRACK NORTHWARD THROUGH TAU 72 ALONG THE
WESTERN PERIPHERY OF THE STR, WHICH REORIENTS NORTH-SOUTH. THE SYSTEM
IS FORECAST TO RAPIDLY WEAKEN AS IT TRACKS OVER THE EASTERN COAST OF
CHINA. NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT,
THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC
FORECAST TRACK.  AT TAU 72, TY 10W IS EXPECTED TO DISSIPATE DUE TO
INCREASING VERTICAL WIND SHEAR AS IT TRACKS CLOSE TO THE UPPER-LEVEL
JET ASSOCIATED WITH A DEEP SHORTWAVE TROUGH OVER NORTHEAST CHINA.
OVERALL, TRACK CONFIDENCE REMAINS HIGH.//
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TY KROSA(11W)
As of 06:00 UTC Aug 10, 2019:
Location: 22.9°N 141.0°E
Maximum Winds: 65 kt ( 120km/h)
Gusts: 80 kt (150km/h)
Minimum Central Pressure: 970 mb
CATEGORY US: 1
WEAKENING
WDPN33 PGTW 100900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (KROSA) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 11W (KROSA), LOCATED APPROXIMATELY 115 NM SOUTH OF
IWO TO, HAS TRACKED WEST-NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS
CONVECTIVE BANDING WRAPPING INTO A DEFINED LOW-LEVEL CIRCULATION
CENTER (LLCC). HOWEVER, DEEP CONVECTION OVER THE CORE AND NORTHWEST
QUADRANT REMAINS COMPARATIVELY WEAK DUE TO THE PRESENCE OF CYCLONIC
FLOW AND CONVERGENCE ALOFT WHILE STRONG DIFFLUENCE OVER THE EASTERN
AND SOUTHERN FLANK CONTINUE TO FUEL DEEP CONVECTIVE BANDING. A 100520
SSMI 85GHZ IMAGE INDICATES TIGHTLY-CURVED BANDING WRAPPING INTO A
DEFINED, BROAD LLCC, WHICH SUPPORTS THE INITIAL POSITION WITH GOOD
CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 65 KNOTS, HEDGED
SLIGHTLY BELOW DVORAK CURRENT INTENSITY ESTIMATES OF 4.5 (77 KNOTS)
BASED ON WARMING CLOUD TOPS ACROSS THE SOUTHERN PERIPHERY. WITH THE
EXCEPTION OF THE COMPLEX, MARGINALLY-FAVORABLE OUTFLOW, VERTICAL WIND
SHEAR AND SST VALUES REMAIN FAVORABLE. TY 11W IS LOCATED WITHIN A
WEAK STEERING ENVIRONMENT WITH A NORTH-SOUTH SUBTROPICAL RIDGE
POSITIONED TO THE EAST, A WEAK STR OVER WESTERN JAPAN AND A BREAK TO
THE NORTH. THEREFORE, TY 11W IS TRACKING SLOWLY POLEWARD (AND
ERRATICALLY).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. IN THE NEXT 72 HOURS, THE PRIMARY STEERING FOR TY 11W WILL
GRADUALLY TRANSITION TO THE BUILDING STR TO THE NORTH OF TY 11W WITH
A NORTHWESTWARD TRACK TOWARD JAPAN, PASSING SOUTHWEST OF IWO TO
AROUND TAU 12. SLIGHTLY DIMINISHED OUTFLOW, WEAK SUBSIDENCE AND
POSSIBLE UPWELLING OF COOLER WATER WILL MAKE THE ENVIRONMENT SOMEWHAT
UNFAVORABLE THROUGH TAU 48 WITH GRADUAL WEAKENING TO ABOUT 60 KNOTS.
AFTER TAU 48, AS THE SYSTEM BEGINS TO ACCELERATE WEST-NORTHWESTWARD
TO NORTHWESTWARD OVER WARM SST, SLIGHT INTENSIFICATION IS EXPECTED.
   C. AFTER TAU 72, TY 11W WILL BEGIN TO RECURVE POLEWARD ALONG THE
SOUTHWEST
PERIPHERY OF THE STR TO THE NORTH, WHICH IS EXPECTED TO WEAKEN AND
REORIENT WITH THE APPROACH OF A DEEP MIDLATITUDE SHORTWAVE TROUGH. TY
11W SHOULD RE-INTENSIFY TO A PEAK INTENSITY OF 70 KNOTS AS POLEWARD
OUTFLOW IMPROVES UNTIL UPPER LEVEL CONVERGENCE AND LAND INTERACTION
GRADUALLY WEAKENS TY 11W. SST VALUES WILL REMAIN CONDUCIVE (28-29C)
DURING THIS EXTENDED PERIOD. NUMERICAL MODEL GUIDANCE DIVERGES
SLIGHTLY BUT REMAINS IN GOOD AGREEMENT WITH SOME UNCERTAINTY IN TRACK
SPEED AS TY 11W APPROACHES THE SOUTHERN COAST OF KYUSHU. BASED ON THE
ERRATIC SHORT-TERM MOTION AND UNCERTAINTY IN THE LATER TAUS, THERE IS
OVERALL MODERATE CONFIDENCE IN THE JTWC FORECAST TRACK.//
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