WPAC: RAI - Post-Tropical

[Hayabusa]

96W INVEST 211209 1800 6.0N 151.0E WPAC 15 0

This is expected to merge with 95W, JTWC seems already set in making 95W the dominant one though (edit they switched to 96W)

[ElectricStorm]

Kinda hard to tell since they're pretty close to each other but it's either this or 95W that's the potential big one the GFS is showing.

[mrbagyo]

[Hayabusa]

They switched to 96W

ABPW10 PGTW 100600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/100600Z-110600ZDEC2021//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 95W) PREVIOUSLY LOCATED
NEAR 4.6N 142.4E HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.
(2) THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED
NEAR 4.6N 142.4E IS NOW LOCATED NEAR 5.7N 149.8E, APPROXIMATELY 156
NM SOUTHWEST OF CHUUK . ANIMATED ENHANCED MULTISPECTRAL IMAGERY
(MSI) DEPICTS FLARING CONVECTION SURROUNDING A WEAK BROAD LOW LEVEL
CIRCULATION (LLC). ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT FOR DEVELOPMENT WITH STRONG POLEWARD OUTFLOW, LOW TO
MODERATE (10-15KT) VERTICAL WIND SHEAR, AND WARM (29-30C) SEA
SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 96W
WILL FOLLOW A WESTWARD TRACK AS IT INTENSIFIES. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1006MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS LOW.

[wxman57]

Finally, an invest for the correct developing disturbance. 95W was never going to develop. We've been tracking this features westward since it was around 170E. 96W already has a broad LLC with increasing convection. Will probably be a TD by tomorrow.

[Sciencerocks]

[mrbagyo]

96W INVEST 211211 0000 5.0N 145.9E WPAC 15 1006

[Hayabusa]

Up to medium

ABPW10 PGTW 110230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS REISSUED/110230Z-110600ZDEC2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/102121ZDEC2021//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT REISSUED//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED
NEAR 5N 149.3E IS NOW LOCATED NEAR 5.0N 145.9E, APPROXIMATELY 385 NM
WEST-SOUTHWEST OF CHUUK, FSM. THE POSITION WAS MOVED APPROXIMATELY
200 NM TO THE WEST BASED ON ANALYSIS OF ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) AND A RECENT ASCAT PASS. THESE DATA REVEAL A
BROAD LOW LEVEL CIRCULATION (LLC) BECOMING ESTABLISHED WITHIN AN
AREA OF SURFACE TROUGHING WITH DISORGANIZED, YET PERSISTENT
CONVECTION IN THE WESTERN PERIPHERY. ENVIRONMENTAL ANALYSIS
INDICATES THAT THE CONDITIONS FOR TROPICAL CYCLONE
DEVELOPMENT ARE FAVORABLE SUPPORTED BY VERY WARM SEA SURFACE
TEMPERATURES (29-30C), LOW TO MODERATE (10-15KTS) VERTICAL WIND
SHEAR, AND FAIR POLEWARD OUTFLOW. GLOBAL MODELS ARE IN AGREEMENT
THAT THE SYSTEM WILL CONTINUE TO DEVELOP OVER THE NEXT 36
TO 48HRS WITH GFS BEING THE MOST AGGRESSIVE. IN ADDITION, THE SYSTEM
IS TRACKING NORTH-NORTHWESTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO
MEDIUM.

[Hayabusa]

HWRF first run, instead of being a happy trigger, keeps it rather weak, weaker than the GFS

[mrbagyo]

GFS is also trending weaker on the latest run - still at typhoon strength but weaker than the previous

[aspen]

GFS and HWRF have trended stronger for their 12z runs — 945mb on the GFS and 952mb on the HWRF.

[Sciencerocks]

[cycloneye]

EC ensembles stronger.

[Sciencerocks]

[Hayabusa]

HWRF 18Z stronger

[Hayabusa]

JMA straight to warning, wonder if JTWC would do the same?
First peak 950 mb

TD a
Issued at 2021/12/12 01:25 UTC
Analisys at 12/12 00 UTC
Category TD
Scale -
Intensity -
Center Position N4°55′(4.9°)
E145°0′(145.0°)
Direction and speed of movement Almost stationary
Central pressure 1004hPa
Maximum wind speed near the center 15m/s(30kt)
Maximum wind gust speed 23m/s(45kt)
Forecast at 12/13 00 UTC
Category TS
Intensity -
Center of probability circle N5°35′(5.6°)
E141°35′(141.6°)
Direction and speed of movement W 15km/h(9kt)
Central pressure 996hPa
Maximum wind speed near the center 20m/s(40kt)
Maximum wind gust speed 30m/s(60kt)
Radius of probability circle 150km(80NM)
Forecast at 12/14 00 UTC
Category STS
Intensity -
Center of probability circle N7°20′(7.3°)
E137°55′(137.9°)
Direction and speed of movement WNW 20km/h(10kt)
Central pressure 980hPa
Maximum wind speed near the center 30m/s(55kt)
Maximum wind gust speed 40m/s(80kt)
Radius of probability circle 240km(130NM)
Storm warning area WIDE320km(175NM)
Forecast at 12/15 00 UTC
Category TY
Intensity Strong
Center of probability circle N9°0′(9.0°)
E133°0′(133.0°)
Direction and speed of movement WNW 25km/h(13kt)
Central pressure 965hPa
Maximum wind speed near the center 35m/s(70kt)
Maximum wind gust speed 50m/s(100kt)
Radius of probability circle 370km(200NM)
Storm warning area WIDE500km(270NM)
Forecast at 12/16 00 UTC
Category TY
Intensity Strong
Center of probability circle N9°35′(9.6°)
E127°50′(127.8°)
Direction and speed of movement W 25km/h(13kt)
Central pressure 950hPa
Maximum wind speed near the center 40m/s(80kt)
Maximum wind gust speed 60m/s(115kt)
Radius of probability circle 520km(280NM)
Storm warning area WIDE700km(370NM)
Forecast at 12/17 00 UTC
Category TY
Intensity Strong
Center of probability circle N9°55′(9.9°)
E122°10′(122.2°)
Direction and speed of movement W 25km/h(14kt)
Central pressure 960hPa
Maximum wind speed near the center 40m/s(75kt)
Maximum wind gust speed 55m/s(105kt)
Radius of probability circle 700km(390NM)
Storm warning area WIDE850km(470NM)

[Hayabusa]

TCFA first...

WTPN21 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 96W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
135 NM EITHER SIDE OF A LINE FROM 5.6N 143.7E TO 8.1N 138.2E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 15 TO 20 KNOTS. METSAT
IMAGERY AT 121200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 5.6N 143.7E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 11
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED
NEAR 5.2N 144.7E IS NOW LOCATED NEAR 5.6N 143.7E APPROXIMATELY 407NM
SOUTHEAST FROM YAP. A LONGITUDINAL AND CHAOTIC DUAL-CLUSTER OF
PERSISTENT CONVECTION HAS STARTED TURNING WITH A POORLY DEFINED LOW
LEVEL CIRCULATION (LLC). CURRENT ANALYSIS INDICATES THE SYSTEM IS
TILTED WITH HEIGHT TO THE NORTH ALONG THE MOST POTENT CONVECTION
WHILE THE LOW LEVELS REMAIN AMBIGUOUS AND ELONGATED. A RECENT
PARTIAL 112352Z ASCAT PASS SHOWS A 20-25 KNOT BAND OF WINDS TO THE
NORTHWEST OF THE POORLY DEFINED LLC. THE ENVIRONMENTAL OUTLOOK FOR
96W IS FULL OF PROMISE WITH WARM SEA SURFACE TEMPERATURES (29-30 C),
WEAK VERTICAL WIND SHEAR (05-10 KTS) AND BURGEONING RADIAL OUTFLOW.
THE GLOBAL MODELS AGREE -WITH ECMWF JUMPING ON THE DEVELOPMENT
BANDWAGON- THAT THE SYSTEM WILL INTENSIFY IN THE NEXT 24 HOURS AND
TRACK WEST. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO
20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007
MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
130300Z.
//
NNNN

[mrbagyo]

[Hayabusa]

Where it will track, if it's northerly (like the HWRF shows), seems to be more stronger (assuming no cold surge to inhibit) than a flat one like over northern Mindanao.

[ChrisH-UK]

Still looking elongated but shows signs of improving.

Source - https://col.st/z5zv1