WPAC: LEKIMA - Post-Tropical

[1900hurricane]

Ha, at least JTWC upped 12Z to 35 kt.

10W LEKIMA 190804 1200 17.6N 131.2E WPAC 35 995

[1900hurricane]

It's also worth nothing that this isn't a system ready to go off yet. ASCAT data showed the center near 18ºN, 131ºE, and there likely hasn't been much movement since then. Basically all the convective activity remains west of the center. There is still plenty of development and organization to go.

[1900hurricane]

Ugh, come on JTWC...

10W LEKIMA 190804 1800 18.3N 130.4E WPAC 35 994

*EDIT for correct storm.

[shah83]

The 06z/12zGFS showing a stall inland China and pulling huge moisture into Shandong, Henan and Jiang provinces is pretty radical, at least Fitow/Rumbia bad.

[Dave C]

It's also worth nothing that this isn't a system ready to go off yet. ASCAT data showed the center near 18ºN, 131ºE, and there likely hasn't been much movement since then. Basically all the convective activity remains west of the center. There is still plenty of development and organization to go.

https://i.imgur.com/dHElu79.gif

Clearly has that easterly shear appearance to it.

[1900hurricane]

It's also worth nothing that this isn't a system ready to go off yet. ASCAT data showed the center near 18ºN, 131ºE, and there likely hasn't been much movement since then. Basically all the convective activity remains west of the center. There is still plenty of development and organization to go.

https://i.imgur.com/dHElu79.gif

Clearly has that easterly shear appearance to it.

It might be a part of it, although shear appears to be less than you'd expect just looking at a water vapor loop or CIMSS analysis. Another contributing reason for the lopsided appearance might be going on in the low levels. The eastern side of the circulation splits off from the strong monsoon westerlies, which may be creating a region of surface divergence, which in turn implies downwards vertical motion. This is also showing up in CIMSS analysis.







 https://twitter.com/1900hurricane/status/1158102523695292417

[euro6208]

WDPN31 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (LEKIMA) WARNING NR
04//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 10W (LEKIMA), LOCATED APPROXIMATELY 513 NM
SOUTH-SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 10 KNOTS
(KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY (EIR) REVEALS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION
(LLC) WITH DEEP CONVECTION TO THE WEST AND SOUTH. THERE IS LOW
CONFIDENCE IN THE INITIAL POSITION WHICH WAS PLACED USING THE EIR
IMAGERY AND SHALLOW BANDING VISIBLE IN A PARTIAL 041633Z AMSR2 89
GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY OF 35 KTS IS CONSISTENT
WITH MULTI-AGENCY DVORAK ESTIMATES OF T2.5 (35 KTS). THE INTENSITY
AND WIND RADII ARE CONSISTENT WITH A 041251Z METOP-B ASCAT PASS THAT
SHOWED A LARGE AREA OF 35 KTS (WITH A FEW 40-45 KT BARBS IN DEEP
CONVECTION) TO THE SOUTH OF THE BROAD LLC. THE ENVIRONMENT IS
FAVORABLE WITH RADIAL OUTFLOW, WARM (29-30 CELSIUS) SEA SURFACE
TEMPERATURE, AND LOW (5-15 KT) VERTICAL WIND SHEAR (VWS). TS 10W IS
TRACKING GENERALLY POLEWARD UNDER THE STEERING INFLUENCE OF A
SUBTROPICAL RIDGE (STR) STRETCHING FROM THE NORTH TO THE EAST OF THE
LLC.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 48, TS 10W IS EXPECTED TO CONTINUE TRACKING
NORTHWESTWARD AND SLOWLY ACCELERATE AS THE STR REORIENTS AND BUILDS
SLIGHTLY. BY TAU 72, THE FORWARD SPEED IS EXPECTED TO BE AROUND 10
KTS. THE INTENSITY GUIDANCE SUPPORTS A STEADY INTENSIFICATION RATE
AND THE SYSTEM SHOULD REACH 70 KTS BY TAU 72. UNCERTAINTY IN THE
MODEL TRACK GUIDANCE FOR THIS PORTION OF THE FORECAST IS VERY HIGH
AS TWO MEMBERS (UKMET AND GALWEM) SHOW A POLEWARD TRACK WHILE ONE
MEMBER (NAVGEM) SHOWS A WESTWARD TRACK. THE REMAINING GUIDANCE IS IN
GOOD AGREEMENT WITH THE JTWC TRACK FORECAST. AT TAU 72, SPREAD IS
OVER 330 NM BUT DECREASES TO 114 NM WHEN EXCLUDING THE THREE
AFOREMENTIONED OUTLIERS. FOR THIS PORTION OF THE FORECAST, THERE IS
VERY LOW CONFIDENCE IN FORECAST TRACK DUE TO HIGH UNCERTAINTY IN
BOTH THE INITIAL POSITION AND MODEL TRACK GUIDANCE.
C. BEYOND TAU 72, TS 10W IS EXPECTED TO CONTINUE ON A
NORTHWESTWARD TRACK ALONG THE SOUTHWEST PERIPHERY OF THE STR AND
INTENSIFY TO 95 KTS BY TAU 120. INTENSITY GUIDANCE BEGINS TO SPREAD
AFTER TAU 72 DUE TO SIGNIFICANT DIFFERENCES IN THE FORECAST TRACK OF
THE MODELS. AS A RESULT, THE INTENSIFICATION RATE FOR THIS PORTION
OF THE FORECAST IS MAINTAINED NEAR THE CLIMATOLOGICAL RATE UNDER
CONTINUED FAVORABLE ENVIRONMENTAL CONDITIONS. POOR AGREEMENT IN THE
TRACK GUIDANCE CONTINUES IN THE EXTENDED PERIOD AND CONFIDENCE IN
THE JTWC TRACK FORECAST REMAINS VERY LOW.//
NNNN

[euro6208]

[euro6208]

Perfect agreement for a Taiwan landfall from GFS and EURO.

[euro6208]

Yikes!

[1900hurricane]

More ASCAT data supports 45-50 kt, but JTWC stays at 35 kt again.

10W LEKIMA 190805 0000 18.8N 130.1E WPAC 35 994

[euro6208]

Intensity forecast has been lowered significantly.

WDPN31 PGTW 050900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (LEKIMA) WARNING NR
06//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 10W (LEKIMA), LOCATED APPROXIMATELY 456 NM
SOUTH-SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) REVEALS AN EXPOSED, BROAD LOW LEVEL CIRCULATION (LLC) WITH DEEP
CONVECTION WRAPPING INTO THE CENTER FROM THE SOUTH. THERE IS FAIR
CONFIDENCE IN THE INITIAL POSITION PLACED USING THE MSI AND SHALLOW
BANDING IN A 050649Z SSMIS 91 GHZ MICROWAVE IMAGE. THE INITIAL
INTENSITY OF 35 KTS IS CONSISTENT WITH MULTI-AGENCY DVORAK ESTIMATES
OF T2.5 (35 KTS). THE ENVIRONMENT IS FAVORABLE WITH RADIAL OUTFLOW,
WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE, AND MODERATE (15-20 KT)
VERTICAL WIND SHEAR (VWS). TS 10W IS TRACKING SLOWLY ALONG THE
SOUTHWEST PERIPHERY OF A SUBTROPICAL RIDGE (STR) THAT IS BEING
DISTORTED BY TS 09W.
3. FORECAST REASONING.
A. RIDGING BUILDING IN FROM THE NORTHEAST LATE IN THE FORECAST HAS
BECOME THE DOMINANT STEERING FEATURE, PULLING THE EXTENDED TRACK
SIGNIFICANTLY FURTHER WEST OVER EASTERN CHINA.
B. THROUGH TAU 48, TS 10W IS EXPECTED TO CONTINUE TRACKING
NORTHWESTWARD AND SLOWLY ACCELERATE AS TS 09W MOVES AWAY AND THE STR
BUILDS BEHIND IT. THE FAVORABLE ENVIRONMENT SHOULD SUPPORT STEADY
INTENSIFICATION TO 65 KTS BY TAU 72. UNCERTAINTY IN THE MODEL TRACK
GUIDANCE FOR THIS PORTION OF THE FORECAST IS HIGH AS THERE IS A 220NM
SPREAD AT TAU 72 WITH THE MOST SIGNIFICANT VARIABILITY BETWEEN NVGM
AND JGSI TRACKS.
C. BEYOND TAU 72, TS 10W IS EXPECTED TO GRADUALLY TURN MORE
POLEWARD AS IT ROUNDS THE STR AXIS AROUND TAU 96. ASSUMING THE SYSTEM
FOLLOWS THE FORECAST TRACK, THE ENVIRONMENT WILL REMAIN FAVORABLE
UNTIL LAND INTERACTION EFFECTS ARE INTRODUCED AS IT BEGINS TRACKING
OVER TAIWAN AROUND TAU 90. TRACK SPREAD AT TAU 120 HAS BEEN
SIGNIFICANTLY REDUCED WITH UNCERTAINTY BETWEEN POSITION OVER COASTAL
CHINA OR FURTHER INLAND. THE HIGH UNCERTAINTY IN THE TRACK GUIDANCE
COULD GREATLY AFFECT THE ENVIRONMENTAL AND LAND INTERACTION EFFECTS,
RESULTING IN HIGH UNCERTAINTY IN THE INTENSITY FORECAST. BASED ON THE
HIGH SPREAD IN THE MODEL GUIDANCE, THERE IS LOW CONFIDENCE IN THE
JTWC TRACK FORECAST.//
NNNN

[1900hurricane]

Looks like it's beginning to cover up the center a little better now. Still very south weighted though.

[Highteeld]

Some sort of structural changes seem to be underway over the last few hours...

[Hayabusa]

Upgraded to STS

STS 1909 (Lekima)
Issued at 07:05 UTC, 6 August 2019

<Analysis at 06 UTC, 6 August>
Scale Large
Intensity -
Center position N19°10' (19.2°)
E129°05' (129.1°)
Direction and speed of movement NNW Slow
Central pressure 980 hPa
Maximum wind speed near center 25 m/s (50 kt)
Maximum wind gust speed 35 m/s (70 kt)
≥ 30 kt wind area S 650 km (350 NM)
N 430 km (230 NM)

<Forecast for 06 UTC, 7 August>
Intensity -
Center position of probability circle N20°35' (20.6°)
E127°10' (127.2°)
Direction and speed of movement NW 10 km/h (6 kt)
Central pressure 970 hPa
Maximum wind speed near center 30 m/s (60 kt)
Maximum wind gust speed 45 m/s (85 kt)
Radius of probability circle 90 km (50 NM)
Storm warning area ALL 170 km (90 NM)

<Forecast for 06 UTC, 8 August>
Intensity -
Center position of probability circle N22°50' (22.8°)
E124°20' (124.3°)
Direction and speed of movement NW 15 km/h (9 kt)
Central pressure 965 hPa
Maximum wind speed near center 35 m/s (70 kt)
Maximum wind gust speed 50 m/s (100 kt)
Radius of probability circle 170 km (90 NM)
Storm warning area ALL 260 km (140 NM)

<Forecast for 06 UTC, 9 August>
Intensity -
Center position of probability circle N25°10' (25.2°)
E121°35' (121.6°)
Direction and speed of movement NW 15 km/h (9 kt)
Central pressure 980 hPa
Maximum wind speed near center 30 m/s (55 kt)
Maximum wind gust speed 40 m/s (80 kt)
Radius of probability circle 260 km (140 NM)
Storm warning area ALL 310 km (170 NM)

<Forecast for 06 UTC, 10 August>
Intensity -
Center position of probability circle N27°25' (27.4°)
E120°25' (120.4°)
Direction and speed of movement NNW 10 km/h (6 kt)
Central pressure 994 hPa
Maximum wind speed near center 20 m/s (40 kt)
Maximum wind gust speed 30 m/s (60 kt)
Radius of probability circle 370 km (200 NM)

<Forecast for 06 UTC, 11 August>
Intensity -
TD
Center position of probability circle N30°50' (30.8°)
E121°25' (121.4°)
Direction and speed of movement N 15 km/h (9 kt)
Central pressure 998 hPa
Radius of probability circle 520 km (280 NM)

[euro6208]

WDPN31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (LEKIMA) WARNING NR
09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 10W (LEKIMA), LOCATED APPROXIMATELY 468 NM
SOUTH OF KADENA AB, HAS TRACKED NORTH-NORTHEASTWARD AT 02 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A
CONSOLIDATING SYSTEM WITH SYMMETRIC DEEP CONVECTION AROUND THE CORE
WITH AN AREA OF DEEP CONVECTION EXTENDING TO THE SOUTH AND WEST. THE
INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE AND IS BASED ON A
052225Z SSMIS 91GHZ MICROWAVE IMAGE, WHICH SHOWS THE DEEP CONVECTION
EXTENDING TO THE SOUTH AND WEST. THE INITIAL INTENSITY ESTIMATE OF 45
KNOTS IS BASED ON DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T3.0 (45
KNOTS) FROM PGTW AND RJTD. ENVIRONMENTAL ANALYSIS SHOWS THAT TS 10W
IS EXPERIENCING NEUTRAL TO UNFAVORABLE (20 TO 25 KNOT) VERTICAL WIND
SHEAR WHICH IS LIMITING DEVELOPMENT. TS 10W HAS A STRONG EQUATORWARD
OUTFLOW CHANNEL WHILE THE POLEWARD OUTFLOW CHANNEL REMAINS
CONSTRAINED BY TS 09W TO THE NORTH. SEA SURFACE TEMPERATURE IS
FAVORABLE FOR DEVELOPMENT WITH TEMPERATURES GREATER THAN 31 DEGREES
CELSIUS. TS 10W IS DRIFTING NORTHWESTWARD WHILE POSITIONED BETWEEN A
SUBTROPICAL RIDGE (STR) TO THE NORTH AND A NEAR EQUATORIAL RIDGE
(NER) TO THE SOUTH.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 48, TS 10W WILL TRACK NORTHWESTWARD AS THE
AFOREMENTIONED RIDGES BUILD. IMPROVING VERTICAL WIND SHEAR AND
FAVORABLE SEA SURFACE TEMPERATURES WILL ALLOW TS 10W TO STEADILY
INCREASE IN INTENSITY, REACHING 70 KNOTS BY TAU 48. AS TS 10W TRACKS
NORTHWESTWARD IT WILL MOVE AWAY FROM TD 11W AND TS 09W WHICH WILL
ALLOW FOR IMPROVED UPPER LEVEL OUTFLOW. SHORTLY BEFORE TAU 72, TS 10W
WILL MAKE LANDFALL IN NORTHERN TAIWAN. DYNAMIC MODEL GUIDANCE IS IN
GOOD AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION
OF THE JTWC FORECAST TRACK.
C. IN THE EXTENDED FORECAST LAND INTERACTION WITH TAIWAN WILL
CAUSE TS 10W TO DECREASE IN INTENSITY, REACHING 50 KNOTS BY TAU 96.
ALSO BY TAU 96, THE STR TO THE NORTH WILL BECOME THE PRIMARY STEERING
FEATURE AND CAUSE TS 10W TO TURN NORTHWARD. AT TAU 96, TS 10W WILL
MAKE LANDFALL IN CENTRAL CHINA AND CONTINUE TO WEAKEN IN INTENSITY AS
IT TRACKS NORTHWARD. DYNAMIC MODEL GUIDANCE HAS A SPREAD OF 375 NM BY
TAU 120, THEREFORE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE
JTWC FORECAST TRACK.//
NNNN

[Hayabusa]

hmm?

2019AUG06 081000 3.7 980.1 59.0 3.7 4.1 5.2 0.5T/hour OFF OFF OFF OFF -29.73 -65.47 EYE -99 IR -0.0 19.25 -128.86 FCST HIM-8 26.3

[mrbagyo]

It has formed a faint eye in visible imagery.
I expect the feature to disappear temporarily since it will probably be obscured by intense convection as part of CDO building process. At least, we now have a vertically stacked system hehe.

I'm a bit worried about Lekima's interaction with 96W though since it might whip the lesser system towards the Western Portion of Luzon bringing dangerous torrential rain.

[euro6208]

WDPN31 PGTW 060900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (LEKIMA) WARNING NR
10//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 10W (LEKIMA), LOCATED APPROXIMATELY 449 NM
SOUTH OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTH-NORTHWESTWARD
AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS A CONSOLIDATING SYSTEM WITH SHALLOW AND FRAGMENTED
RAIN BANDS TRAILING FROM THE SOUTHWEST. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON A FORMATIVE MICROWAVE EYE IN THE
060636Z SSMIS MICROWAVE IMAGE. THE INITIAL INTENSITY OF 50 KNOTS IS
AVERAGED FROM AGENCY DVORAK ESTIMATES RANGING FROM T3.0/45KTS TO
T3.5/55KTS. ENVIRONMENTAL ANALYSIS SHOWS THAT TS 10W IS UNDER
MODERATE (20 TO 25 KNOT) VERTICAL WIND SHEAR (VWS) THAT IS OFFSET BY
A STRONG EQUATORWARD OUTFLOW. SSTS ARE HIGHLY FAVORABLE AT 31
CELSIUS. THE CYCLONE IS IN A COL BETWEEN A SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST AND A NEAR EQUATORIAL RIDGE (NER) TO THE SOUTH BUT
APPEARS TO BE MOVING SLOWLY NORTHWARD.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THE STR WILL SLOWLY ASSUME STEERING AND DRIVE TS 10W
NORTHWESTWARD TOWARD NORTHERN TAIWAN. THE VWS IS EXPECTED TO RELAX.
THIS PLUS IMPROVED RADIAL OUTFLOW AND WARM SSTS WILL PROMOTE STEADY
INTENSIFICATION TO A PEAK OF 75 KNOTS BY TAU 48. AFTERWARD, LAND
INTERACTION WILL REDUCE THE SYSTEM TO 65 KNOTS AFTER IT MAKES
LANDFALL JUST EAST OF TAIPEI. DYNAMIC MODEL GUIDANCE IS IN GOOD
AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE
JTWC FORECAST TRACK.
C. BEYOND TAU 72, TS 10W WILL ROUND THE STR AXIS AND TRACK MORE
POLEWARD THROUGH THE TAIWAN STRAIT THEN DRAG ACROSS THE EASTERN
CHINESE COAST. LAND INTERACTION AND INCREASING VWS WILL GRADUALLY
ERODE THE SYSTEM DOWN TO 30 KNOTS BY TAU 120 AS IT APPROACHES
SHANGHAI. DYNAMIC MODEL GUIDANCE SPREADS OUT TO OVER 260 NM BY TAU
120 WITH NAVGEM ON THE EXTREME RIGHT OF THE ENVELOPE. THEREFORE,
THERE IS LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC FORECAST
TRACK THAT IS LAID JUST LEFT OF CONSENSUS TO OFFSET THE UNLIKELY
NAVGEM SOLUTION THAT DRIVES THE CYCLONE INTO THE STR.//
NNNN

[euro6208]

TXPQ26 KNES 060921
TCSWNP

A. 10W (LEKIMA)

B. 06/0830Z

C. 19.4N

D. 128.8E

E. ONE/HIMAWARI-8

F. T4.0/4.0/D1.5/24HRS

G. IR/EIR/VIS

H. REMARKS...THIS INTENSITY ESTIMATE WAS DERIVED USING 4 KM IR DATA.
OW EYE IS EMBEDDED IN DG AND SURROUNDED BY MG RESULTING IN A DT OF
4.5 WITH NOTHING ADDED FOR EYE ADJUSTMENT. MET = 3.5 AND PT = 4.0.
FT IS BASED ON PT AS SYSTEM HAS RAGGED EYE AND 4.5 DT DOES NOT REPRESENT
CURRENT SATELLITE INTENSITY.

I. ADDL POSITIONS

NIL


...KIBLER