WPAC: MAYSAK - Post-Tropical

[doomhaMwx]

Large windfield.

[doomhaMwx]

WDPN31 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (TEN) WARNING NR
01//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 10W (TEN), LOCATED APPROXIMATELY 603 NM
SOUTH-SOUTHEAST OF KADENA AB, OKINAWA, HAS TRACKED WEST-NORTHWESTWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A SOMEWHAT DISORGANIZED CIRCULATION, WITH DEEP
FLARING CONVECTION DISPLACED SOUTHWEST OF THE LOW LEVEL CIRCULATION
CENTER (LLCC). A 270030Z AMSU-B 89GHZ COMPOSITE MICROWAVE IMAGE
REVEALS FORMATIVE BANDING WRAPPING INTO AN INCREASINGLY CONSOLIDATED
LLCC, WITH THE AFOREMENTIONED DEEP CONVECTION DISPLACED WELL
SOUTHWEST OF THE LLCC. THE INITIAL POSITION IS PLACED WITH MODERATE
CONFIDENCE BASED ON AN ANALYSIS OF THE LOW LEVEL CONVECTIVE BANDS,
SUPPORTED BY A 270030Z ASCAT-B PASS WHICH CONFIRMS THAT THE CENTER IS
STILL FAIRLY BROAD BUT QUICKLY CONSOLIDATING INTO A TIGHTER
CIRCULATION. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T1.5 (25
KNOTS) FROM BOTH PGTW AND RJTD, AS WELL AS THE PREVIOUSLY MENTIONED
ASCAT PASS, WHICH CONFIRMS A LARGE SWATH OF 25 KNOTS WINDS TO THE
SOUTH AND A SMALLER AREA OF 25 KNOT WINDS TO THE NORTH OF THE
ASSESSED CENTER. THE ASCAT DATA ALSO SHOWS AN AREA OF 30-35 KNOT,
WITH EVEN HIGHER WINDS ON THE EDGE OF THE SWATH, TO THE SOUTHWEST;
HOWEVER, THE 30-35 KNOT WINDS ARE ISOLATED AND ARE UNDER A BURST OF
DEEP CONVECTION DISPLACED FROM THE CENTER OF CIRCULATION AND ARE
ASSESSED AS NOT REPRESENTATIVE OF THE OVERALL INTENSITY.
ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR FURTHER DEVELOPMENT WITH
LOW TO MODERATE (10-20 KNOTS) VERTICAL WIND SHEAR (VWS), STRONG
DIVERGENT EQUATORWARD OUTFLOW AS WELL AS VERY WARM SST VALUES (31C)
AND HIGH OCEAN HEAT CONTENT VALUES
REFLECTING A DEEP, WARM POOL OF WATER. TD 10W IS CURRENTLY TRACKING
SLOWLY WESTWARD IN A WEAK STEERING ENVIRONMENT BETWEEN A NEAR
EQUATORIAL RIDGE (NER) THAT EXTENDS FROM THE PHILIPPINES EASTWARD
ALONG 10 DEGREES NORTH LATITUDE, A STRONG SUBTROPICAL RIDGE (STR) TO
THE NORTH AND A DEEP-LAYER SUBTROPICAL LOW CENTERED NEAR THE NORTHERN
MARIANAS.
3. FORECAST REASONING.
A. THIS IS THE INITIAL PROGNOSTIC REASONING MESSAGE FOR THIS
SYSTEM AND SETS THE FORECAST PHILOSOPHY.
B. THE WEAK STEERING PATTERN IS FORECAST TO REMAIN RELATIVELY
STAGNANT THROUGH THE NEXT DAY, WHICH WILL RESULT IN A SLOW WESTWARD
TRACK MOTION THROUGH TAU 24. ENVIRONMENTAL CONDITIONS REMAIN
FAVORABLE THROUGH TAU 24 AS WELL, WITH DIVERGENT EQUATORWARD OUTFLOW,
VERY WARM SSTS, HIGH OHC AND STEADILY DECREASING VWS, ALLOWING FOR
STEADY INTENSIFICATION. BETWEEN TAU 24 AND TAU 36, THE UPPER LEVEL
PATTERN BEGINS TO CHANGE, WITH THE NER MOVING NORTHWARD AND
REORIENTING INTO A NORTH-SOUTH ORIENTATED RIDGE AXIS ALONG ROUGHLY
THE 140 EAST LONGITUDE LINE, ALLOWING TD 10W TO SLOWLY TURN
NORTHWARD. AT THE SAME TIME, A TROPICAL UPPER TROPOSPHERIC TROUGH
(TUTT) CELL CURRENTLY NORTH OF GUAM WILL MOVE WEST INTO A POSITION
NORTH-NORTHEAST OF THE SYSTEM. WHILE EQUATORWARD OUTFLOW WILL REMAIN
ROBUST DURING THIS TIMEFRAME, THE TUTT WILL PROVIDE SOME CONVERGENT
FLOW ON THE NORTH SIDE OF THE SYSTEM, LEADING TO A PERIOD OF SLOWER
DEVELOPMENT. FROM TAU 36 TO TAU 72, THE NER-STR RIDGE COMPLEX TO THE
EAST BECOMES ORIENTED NORTHWEST-SOUTHEAST, PUSHING TD 10W ONTO A
FASTER TRACK TOWARDS THE NORTH-NORTHWEST. AT THIS TIME, THE TUTT WILL
CONTINUE MOVING WEST AND AN UPPER LEVEL ANTICYCLONE IS FORECAST TO
DEVELOP JUST EAST OF TD 10W ALLOWING FOR DEVELOPMENT OF A STRONG
POLEWARD OUTFLOW CHANNEL, IN ADDITION TO THE ALREADY ESTABLISHED
EQUATORWARD CHANNEL, LEADING TO A PERIOD OF RAPID INTENSIFICATION
BETWEEN TAU 36 AND TAU 72. DYNAMIC MODEL GUIDANCE IS IN STRONG
AGREEMENT IN THE OVERALL SCENARIO BUT DO HAVE SOME DISAGREEMENT IN
THE EXACT TIMING OF THE TURN NORTH AND IN THE EXTENT OF THE WESTWARD
MOTION IN THE NEAR-TERM, LEADING TO A 140NM SPREAD AT TAU 72.
C. IN THE EXTENDED PERIOD, THE AFOREMENTIONED RIDGE COMPLEX TO THE
EAST WILL REORIENT ONCE AGAIN TO A MORE NORTH-SOUTH AXIS, ALLOWING
FOR A SLOW TURN ONTO A MORE NORTHWARD TRACK AFTER TAU 96. TD 10W IS
FORECAST TO REACH PEAK INTENSITY OF 110 KNOTS AT TAU 96 UNDER VERY
FAVORABLE CONDITIONS OF LOW VWS, ROBUST, DIVERGENT POLEWARD OUTFLOW
AND VERY WARM SSTS. AS THE SYSTEM ENTERS THE EAST CHINA SEA, IT IS
FORECAST TO WEAKEN SLIGHTLY, AS COOLER SSTS IN THE WAKE OF THE
PASSAGE OF TY 09W THROUGH THE AREA AND INCREASING VWS, WILL OFFSET
STRONG POLEWARD OUTFLOW INTO THE BASE OF AN APPROACHING MID-LATITUDE
TROUGH. DYNAMIC MODEL GUIDANCE IS IN FAIR AGREEMENT THROUGH TAU 120.
CROSS-TRACK SPREAD INCREASES TO A MODEST 178NM AT TAU 120 BUT ALONG-
TRACK SPREAD INCREASES SIGNIFICANTLY FROM TAU 96 TO TAU 120 AS THE
MODELS DIFFER IN THE AMOUNT OF INTERACTION WITH THE APPROACHING MID-
LATITUDE TROUGH. THE JTWC FORECAST TRACK LIES WEST OF THE MULTI-MODEL
CONSENSUS THROUGH TAU 72, FAVORING THE ECMWF SOLUTION, THEN LIES VERY
CLOSE TO THE CONSENSUS, BUT FASTER, THROUGH TAU 120, WITH OVERALL
MODERATE CONFIDENCE IN THE OFFICIAL TRACK.//
NNNN

[mrbagyo]

[euro6208]

TPPN11 PGTW 280616

A. TROPICAL DEPRESSION 10W (E OF LUZON)

B. 28/0550Z

C. 16.43N

D. 129.58E

E. FIVE/HMWRI8

F. T2.0/2.0 STT: S0.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 40A/PBO SBC/ANMTN. CNVCTN WRAPS .35 ON LOG10 SPIRAL
YIELDING A DT OF 2.0. MET AND PT AGREE. DBO DT.

I. ADDITIONAL POSITIONS:
28/0032Z 16.78N 130.87E MMHS


RHOADES

[dexterlabio]

This is now Tropical Storm Maysak.

[euro6208]

That outflow is just incredible and it'll get even more well defined.

[Hayabusa]

[euro6208]

TS 2009 (Maysak)
Issued at 07:25 UTC, 28 August 2020

<Analysis at 06 UTC, 28 August>
Scale -
Intensity -
Center position N17°10' (17.2°)
E130°10' (130.2°)
Direction and speed of movement Almost stationary
Central pressure 996 hPa
Maximum sustained wind speed 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
≥ 30 kt wind area SW 280 km (150 NM)
NE 165 km (90 NM)

<Forecast for 06 UTC, 29 August>
Intensity -
Center position of probability circle N17°10' (17.2°)
E129°35' (129.6°)
Direction and speed of movement Almost stationary
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 65 km (35 NM)

<Forecast for 06 UTC, 30 August>
Intensity -
Center position of probability circle N19°40' (19.7°)
E129°55' (129.9°)
Direction and speed of movement N 10 km/h (6 kt)
Central pressure 975 hPa
Maximum wind speed near center 30 m/s (60 kt)
Maximum wind gust speed 45 m/s (85 kt)
Radius of probability circle 110 km (60 NM)
Storm warning area E 220 km (120 NM)
W 165 km (90 NM)

<Forecast for 06 UTC, 31 August>
Intensity Very strong
Center position of probability circle N24°35' (24.6°)
E128°35' (128.6°)
Direction and speed of movement N 25 km/h (13 kt)
Central pressure 950 hPa
Maximum wind speed near center 45 m/s (85 kt)
Maximum wind gust speed 60 m/s (120 kt)
Radius of probability circle 185 km (100 NM)
Storm warning area E 410 km (220 NM)
W 300 km (160 NM)

<Forecast for 06 UTC, 1 September>
Intensity Very strong
Center position of probability circle N27°40' (27.7°)
E125°30' (125.5°)
Direction and speed of movement NW 20 km/h (10 kt)
Central pressure 950 hPa
Maximum wind speed near center 45 m/s (85 kt)
Maximum wind gust speed 60 m/s (120 kt)
Radius of probability circle 260 km (140 NM)
Storm warning area E 480 km (260 NM)
W 430 km (230 NM)

<Forecast for 06 UTC, 2 September>
Intensity -
Center position of probability circle N30°35' (30.6°)
E125°25' (125.4°)
Direction and speed of movement N 15 km/h (7 kt)
Central pressure 955 hPa
Maximum wind speed near center 40 m/s (80 kt)
Maximum wind gust speed 60 m/s (115 kt)
Radius of probability circle 370 km (200 NM)
Storm warning area ALL 540 km (290 NM)

[euro6208]

WDPN31 PGTW 280900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MAYSAK)
WARNING NR 02//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 10W (MAYSAK), LOCATED APPROXIMATELY
610 NM SOUTH OF KADENA AB, HAS TRACKED WEST-SOUTHWESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A DEVELOPING LOW LEVEL CIRCULATION CENTER
(LLCC) PARTIALLY OBSCURED BY DEEP CONVECTION OVER THE WESTERN
SEMICIRCLE, AND FLARING CONVECTION OVER THE EASTERN SEMICIRCLE. THE
INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE
PARTIALLY OBSCURED LLCC IN THE MSI LOOP AND THE LOW LEVEL FEATURES
PRESENT IN THE MICROWAVE IMAGERY FROM A 280513Z ATMS PASS. THE
INITIAL INTENSITY OF 30 KTS IS PLACED WITH HIGH CONFIDENCE BASED ON
MULTIAGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.0 (30 KTS, PGTW AND
RJTD) AND THE 30 KTS WINDS DEPICTED IN BOTH A 280033Z ASCAT-B
AND 280125Z ASCAT-C PASS THAT ARE POSITIONED TO THE SOUTHWEST OF THE
LOW LEVEL CIRCULATION FEATURE. THE WINDFIELD IN THE SCATTEROMETRY
DATA ALSO CONSTRAINS THE INITIAL POSITION, HOWEVER THE LOW LEVEL
CIRCULATION IN THE DATA REMAINS ELONGATED ALONG THE WEST TO EAST
AXIS. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR FURTHER DEVELOPMENT
WITH DIVERGENT EQUATORWARD OUTFLOW AND VERY WARM (30-31 CELSIUS) SEA
SURFACE TEMPERATURES (SST) OFFSET SLIGHTLY BY MODERATE (15-20 KTS)
VERTICAL WIND SHEAR (VWS) AND CONVERGENT FLOW ALOFT TO THE NORTH OF
THE SYSTEM STEMMING FROM AN INCOMING TROPICAL UPPER TROPOSPHERIC TROUGH
(TUTT) CELL TO THE EAST. OCEAN HEAT CONTENT IS VERY HIGH (GREATER THAN
125 JOULES PER SQUARE CENTIMETER). THE SYSTEM IS TRACKING SLOWLY IN A
WEAK STEERING ENVIRONMENT INDUCED BY AN EXTENSION OF A NEAR EQUATORIAL
RIDGE POSITIONED TO THE SOUTH AND EAST OF THE SYSTEM CENTER THAT EXTENDS
FROM THE PHILIPPINES EASTWARD ALONG 10 DEGREES NORTH LATITUDE, A STRONG
SUBTROPICAL RIDGE (STR) TO THE NORTH AND A DEEP-LAYER SUBTROPICAL LOW
CENTERED NEAR THE NORTHERN MARIANAS.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
B. TD 10W WILL CONTINUE ITS SLOW, GENERALLY WESTWARD TRACK UNDER THE
INFLUENCE OF THE CURRENT WEAK STEERING PATTERN THROUGH TAU 12. STEADY
INTENSIFICATION TO 50 KTS WILL TAKE PLACE DURING THIS TIME AS THE SYSTEM
TRACKS OVER VERY WARM WATERS AND THROUGH CONTINUED MODERATE VWS AND
CONVERGENT FLOW ALOFT TO THE NORTH FROM THE AFOREMENTIONED TUTT CELL.
DECREASING VWS FROM TAU 12 TO TAU 24, COUPLED WITH THE WARM SST AND
AND CONTINUED DIVERGENT EQUATORWARD OUTFLOW, WILL ALLOW FOR FURTHER
INTENSIFICATION TO 50 KTS BY TAU 24. AFTER THIS TIME, THE CONVERGENT FLOW
FROM THE TUTT CELL WILL BECOME DIVERGENT AS THE THE CELL PROPAGATES
WESTWARD. BETWEEN TAU 24 AND TAU 36, A REORIENTATION OF THE STEERING
RIDGES WILL ALSO TAKE PLACE WITH THE NER MOVING NORTHWARD AND REORIENTING
INTO A NORTH-SOUTH ORIENTATED RIDGE AXIS ALONG ROUGHLY THE 140 EAST
LONGITUDE LINE, RESULTING IN A GENERALLY NORTHWARD TRACK BETWEEN THESE
TIMES. AT TAU 36 THE ENHANCED OUTFLOW FROM THE TUTT CELL, ALONG WITH THE
CONTINUED HIGH OCEAN HEAT CONTENT, VERY WARM SSTS AND LOW (5-10 KTS) VWS
WILL ALLOW THE SYSTEM TO INTENSIFY, POSSIBLY RAPIDLY, FROM TAU 36 TO TAU
48 AT WHICH TIME THE SYSTEM WILL REACH AN INTENSITY OF 80 KTS. AFTER THIS
TIME, THE SYSTEM WILL BEGIN TO TRACK ALONG THE PERIPHERY OF THE SUBTROPICAL
RIDGE TO THE EAST, RESULTING IN A NORTH-NORTHWESTWARD TRACK. THE ENVIRONMENT
IS EXPECTED TO REMAIN VERY FAVORABLE FOR FURTHER INTENSIFICATION AND WILL
RESULT IN FURTHER INTENSIFICATION TO 100 KTS BY TAU 72. NUMERICAL MODEL
SOLUTIONS ARE IN POOR AGREEMENT ON THE TIMING OF THE STEERING RIDGE
REPOSITIONING, WHICH LEADS TO A 255 NM CROSS TRACK SPREAD IN SOLUTIONS BY
TAU 72. THIS LARGE SPREAD IN SOLUTIONS LENDS OVERALL FAIR CONFIDENCE IN THE
INITIAL PORTION OF THE JTWC FORECAST TRACK.
C. IN THE EXTENDED PERIOD, THE AFOREMENTIONED RIDGE COMPLEX TO THE
EAST WILL REORIENT ONCE AGAIN, DEEPENING AFTER TAU 72, AND BECOME THE
PRIMARY STEERING MECHANISM OF THE STORM. THIS WILL LEAD TO A GENERALLY
NORTHWESTWARD TRACK INITIALLY, AND THEN TO A NORTHWARD TRACK AS TD 10W
APPROACHES THE SUBTROPICAL RIDGE AXIS. TD 10W IS FORECAST TO REACH PEAK
INTENSITY OF 110 KNOTS AT TAU 96 UNDER VERY FAVORABLE CONDITIONS OF LOW
VWS, ROBUST, DIVERGENT POLEWARD OUTFLOW AND VERY WARM SSTS. AS THE SYSTEM
ENTERS THE EAST CHINA SEA, IT IS FORECAST TO WEAKEN SLIGHTLY, AS COOLER
SSTS IN THE WAKE OF THE PASSAGE OF TY 09W THROUGH THE AREA AND INCREASING
VWS, WILL OFFSET STRONG POLEWARD OUTFLOW INTO THE BASE OF AN APPROACHING
MID-LATITUDE TROUGH. THIS SLIGHT WEAKENING WILL BRING THE INTENSITY DOWN
TO 100 KTS BY TAU 120. NUMERICAL MODEL SOLUTIONS MAINTAIN A NEARLY 255 NM
CROSS TRACK SPREAD THROUGH THE REMAINDER OF THE FORECAST. ALONG TRACK
CROSS SPREAD HAS IMPROVED SINCE THE LAST SET OF NUMERICAL MODEL
CALCULATIONS, WITH AN AVERAGE 120 NM SPREAD BETWEEN TAU 72 AND TAU 120.
THE JTWC FORECAST TRACK LIES WEST OF THE MULTI-MODEL CONSENSUS THROUGH TAU
72, FAVORING THE ECMWF SOLUTION, THEN LIES VERY CLOSE TO THE CONSENSUS,
ALBEIT WITH A FASTER TRACK, THROUGH TAU 120. DUE TO THE SPREAD IN MODEL
SOLUTIONS AND UNCERTAINTY IN THE TIMING OF STEERING RIDGE REPOSITIONING,
THE OVERALL JTWC FORECAST TRACK IS PLACED WITH OVERALL FAIR CONFIDENCE.//
NNNN

[aspen]

This is now Tropical Storm Maysak.

Now it’s time to see how it’ll compare to the previous Maysak.

[aspen]

Maysak’s slow motion would make it vulnerable to upwelling. However, it’s sitting over some of the highest OHC on the planet, and will be within it for the next ~60 hours. If it develops an inner core quickly, it could start to rapidly intensify while it remains over the OHC pocket.

[mrbagyo]

Coldest convection so far this season

[euro6208]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.0
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 28 AUG 2020 Time : 113000 UTC
Lat : 16:30:53 N Lon : 129:35:48 E


CI# /Pressure/ Vmax
2.4 / 998.6mb/ 34.0kt


Final T# Adj T# Raw T#
2.4 2.6 2.7

Center Temp : -73.6C Cloud Region Temp : -72.5C

Scene Type : UNIFORM CDO CLOUD REGION

Subtropical Adjustment : OFF

Extratropical Adjustment : OFF

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : 0.7T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : N/A
- Environmental MSLP : 1005mb

Satellite Name : HIM-8
Satellite Viewing Angle : 23.2 degrees

****************************************************

[euro6208]

[Hayabusa]

Strong forecast peak, they had Bavi peaking 940 mb at one point but didn't pan out

<Forecast for 12 UTC, 31 August>
Intensity Very strong
Center position of probability circle N25°40' (25.7°)
E128°00' (128.0°)
Direction and speed of movement NNW 25 km/h (14 kt)
Central pressure 925 hPa
Maximum wind speed near center 50 m/s (95 kt)
Maximum wind gust speed 70 m/s (135 kt)
Radius of probability circle 185 km (100 NM)
Storm warning area ALL 390 km (210 NM)

[euro6208]

 https://twitter.com/EarthUncutTV/status/1299321023435649024

[aspen]

Convection does seem to be slightly displaced, indicating a substantial amount of shear, but Maysak has enough to work with once shear eventually lessens.

[euro6208]

10W MAYSAK 200828 1200 16.5N 129.1E WPAC 35 1001

[euro6208]

EURO makes a beeline for South Korea and peaks Maysak at 950's.

GFS 960's.

[euro6208]

NAVGEM bombs this into 931 mb.

ICON 949 mb.