Lekima and Krosa both downgraded. Krosa expected South of Japan in 4 days as a typhoon

Météo974

M974World

WESTERN NORTH PACIFIC

TS LEKIMA(10W)
As of 12:00 UTC Aug 10, 2019:
Location: 30.8°N 120.7°E
Maximum Winds: 60 kt ( 110km/h)
Gusts: 75 kt ( 140km/h)
Minimum Central Pressure: 966 mb
WEAKENING
WDPN31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (LEKIMA) WARNING NR 27//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 10W (LEKIMA), LOCATED APPROXIMATELY 48 NM
WEST-SOUTHWEST OF SHANGHAI, CHINA, HAS TRACKED NORTH-NORTHEASTWARD
AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A WEAKENING SYSTEM WITH LIMITED DEEP
CONVECTION DISPLACED OVER THE NORTHERN PERIPHERY. A 101029Z SSMIS
91GHZ 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 (5-10 KNOTS) AND STRONG POLEWARD OUTFLOW ENHANCED BY A
SHORTWAVE TROUGH TO THE NORTHWEST. THEREFORE, INTERACTION WITH LAND
AND FRICTIONAL EFFECTS ARE THE PRIMARY WEAKENING MECHANISM. TS 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. TS 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, TS 10W IS EXPECTED TO DISSIPATE DUE TO
UNFAVORABLE VERTICAL WIND SHEAR (40-45 KNOTS) 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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TS KROSA(11W)
As of 12:00 UTC Aug 10, 2019:
Location: 22.8°N 140.7°E
Maximum Winds: 60 kt ( 110km/h)
Gusts: 75 kt (140km/h)
Minimum Central Pressure: 974 mb
WEAKENING
WDPN33 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (KROSA) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 11W (KROSA), LOCATED APPROXIMATELY 124 NM
SOUTH-SOUTHWEST OF IWO TO, HAS TRACKED WEST-SOUTHWESTWARD AT 03 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
(EIR) 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 101227 AMSU 89GHZ 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 60 KNOTS,
HEDGED SLIGHTLY BELOW DVORAK CURRENT INTENSITY ESTIMATES OF T4.0-4.5
(65-77 KNOTS) BASED ON WARMING CLOUD TOPS ACROSS THE SOUTHERN
PERIPHERY. A 100933Z SATCON ESTIMATE FURTHER SUPPORTS THIS INTENSITY
ESTIMATE. DESPITE THE COMPLEX, MARGINALLY-FAVORABLE OUTFLOW, LOW
VERTICAL WIND SHEAR (5-10 KNOTS) AND WARM SST VALUES (28-29 DEGREES
CELSIUS), THE ENVIRONMENT REMAINS FAVORABLE. TS 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, TS 11W IS TRACKING SLOWLY POLEWARD.
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 TS 11W CONTINUE
TRANSITIONING TO THE BUILDING STR TO THE NORTH OF TS 11W WITH A
NORTHWESTWARD TRACK TOWARD JAPAN. SLIGHTLY DIMINISHED OUTFLOW, WEAK
SUBSIDENCE AND POSSIBLE UPWELLING OF COOLER WATER WILL MAKE THE
ENVIRONMENT SOMEWHAT UNFAVORABLE THROUGH TAU 36 WITH GRADUAL
WEAKENING TO ABOUT 55 KNOTS. AFTER TAU 36, AS THE SYSTEM BEGINS TO
ACCELERATE WEST-NORTHWESTWARD TO NORTHWESTWARD OVER WARM SST, SLIGHT
INTENSIFICATION IS EXPECTED.
   C. AFTER TAU 72, TS 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. TS 11W SHOULD RE-INTENSIFY SLIGHTLY TO A PEAK INTENSITY OF 70
KNOTS AS TRACK SPEED INCREASES AROUND TAU 96 UNTIL UPPER LEVEL
CONVERGENCE AND LAND INTERACTION GRADUALLY TS 11W AS IT MAKES
LANDFALL IN KYUSHU. SST VALUES WILL REMAIN CONDUCIVE (28-29 DEGREES
CELSIUS) DURING THIS EXTENDED PERIOD. NUMERICAL MODEL GUIDANCE HAS
CONTINUED TO IMPROVE WITH LIMITED ALONG TRACK SPREAD AND NO
SIGNIFICANT OUTLIERS. BASED ON THE CURRENT ERRATIC MOTION THERE IS
OVERALL MODERATE CONFIDENCE IN THE JTWC FORECAST TRACK.//
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