WPAC: HALONG - Post-Tropical

[aspen]

Halong may be starting to form an eye: https://www.weathernerds.org/satellite/ ... rnerds.png

This is supported by microwave imagery showing a nearly complete early eyewall, but it’s possible the eye on IR imagery is just a warm spot.

[mrbagyo]

[aspen]

Maybe trying to build a more compact CDO?

https://www.weathernerds.org/satellite/ ... ascatb=Off

[aspen]

Halong’s tight cluster of <-85 C convection is just crazy. Once the eyewall closes off, I could see this bombing out, especially with the slightly increasing OHC and improving outflow channels ahead.

[Hayabusa]

STS 1923 (Halong)
Issued at 18:50 UTC, 3 November 2019

<Analysis at 18 UTC, 3 November>
Scale -
Intensity -
Center position N16°35' (16.6°)
E153°35' (153.6°)
Direction and speed of movement NW 15 km/h (7 kt)
Central pressure 985 hPa
Maximum wind speed near center 30 m/s (55 kt)
Maximum wind gust speed 40 m/s (80 kt)
≥ 50 kt wind area ALL 70 km (40 NM)
≥ 30 kt wind area E 390 km (210 NM)
W 220 km (120 NM)

[aspen]

Best track intensity is up to 65 kt/982 mbar. Halong is now a Category 1 typhoon.

[1900hurricane]

Has the cyan ring on the latest F-18 pass.

[mrbagyo]

[aspen]

https://www.nrlmry.navy.mil/tcdat/tc19/WPAC/24W.HALONG/tc_ssmis/91h/2degreeticks/20191103.1909.f18.x.91h.24WHALONG.65kts-982mb-167N-1535E.097pc.jpg

If the eyewall gets stronger and the eye clears, we could see Halong explode within the next 12-24 hours. It’s possible it could go pinhole judging by the size of the eye in that microwave image.

[1900hurricane]

Sun is up.

[Hayabusa]

WDPN31 PGTW 032100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (HALONG) WARNING NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 24W (HALONG), LOCATED APPROXIMATELY 453 NM EAST-
NORTHEAST OF SAIPAN, CNMI, HAS TRACKED NORTHWESTWARD AT 10 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS THE SYSTEM CONTINUED TO DEEPEN AS IT DEVELOPED A 10-NM
RAGGED AND OBSCURED OBLONG EYE. THE INITIAL POSITION IS PLACED WITH
GOOD CONFIDENCE BASED ON THE EYE FEATURE, SLIGHTLY ADJUSTED FOR
TILT. THE INITIAL INTENSITY OF 65KTS IS BASED ON THE PGTW DVORAK
INTENSITY ESTIMATE OF T4.0/65KTS. ENVIRONMENTAL ANALYSIS REVEALS
FAVORABLE CONDITIONS WITH NEAR-RADIAL OUTFLOW, LOW (<15KTS) VERTICAL
WIND SHEAR (VWS), WARM SST (29-30C) AND FAVORABLE OCEAN HEAT CONTENT
VALUES. TY 24W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A
DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 24W WILL CONTINUE ON ITS CURRENT TRACK THROUGH TAU 36.
AFTERWARD, IT WILL ROUND THE STR AXIS AND TURN NORTHWARD THEN
ACCELERATE NORTHEASTWARD ON THE POLEWARD SIDE OF THE STR AND BEGIN
EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH THE MIDLATITUDE
WESTERLIES. THE SYSTEM WILL INTENSIFY UNDER FAVORABLE CONDITIONS TO
A PEAK OF 105 KNOTS BY TAU 48 DUE TO IMPROVED POLEWARD OUTFLOW INTO
THE MIDLATITUDE WESTERLIES. THE NUMERICAL MODELS ARE IN FAIR
AGREEMENT WITH THE TRACK AND TIMING OF THE RECURVE LENDING HIGH
CONFIDENCE TO THIS PORTION OF THE JTWC TRACK FORECAST.
C. IN THE EXTENDED PERIOD, TY HALONG WILL CONTINUE TO ACCELERATE
NORTHEASTWARD AS IT TRACKS WITHIN THE MIDLATITUDE WESTERLIES AND
SHOULD COMPLETE ETT BY TAU 120. THE SYSTEM IS FORECAST TO SLOW AFTER
TAU 96 AS IT ENCOUNTERS A STRONG, LOW-LEVEL MIDLATITUDE HIGH, WHICH
MAY TURN THE SYSTEM MORE POLEWARD. TY 24W WILL WEAKEN RAPIDLY DUE TO
INCREASING VWS AND COOLER SST, HOWEVER, THE SYSTEM WILL STILL BE A
GALE FORCE COLD-CORE LOW AT TAU 120 WITH AN EXPANSIVE WIND FIELD.
NUMERICAL MODELS DIVERGE SIGNIFICANTLY AFTER TAU 72, LENDING LOW
CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.//
NNNN

[aspen]

Looking very healthy right now, with impressive outflow and a couple of hot towers trying to wrap around and form an eye. Halong may reach 75-85 kt for the next advisory if that eye starts to clear out.

[Highteeld]

0z HWRF takes Halong to near cat 5 in 24 hours.

[Highteeld]

0z HWRF takes Halong to near cat 5 in 24 hours.

[aspen]

Convection has maxed out yet again around <-85 C as the eye attempts to clear/form. If the eye is able to open in time, we could see a 90-100 kt system for the next advisory.

[Hayabusa]

TY 1923 (Halong)
Issued at 12:45 UTC, 4 November 2019

<Analysis at 12 UTC, 4 November>
Scale -
Intensity -
Center position N18°10' (18.2°)
E152°50' (152.8°)
Direction and speed of movement NW 15 km/h (9 kt)
Central pressure 970 hPa
Maximum wind speed near center 35 m/s (70 kt)
Maximum wind gust speed 50 m/s (100 kt)
≥ 50 kt wind area ALL 130 km (70 NM)
≥ 30 kt wind area NE 440 km (240 NM)
SW 280 km (150 NM)

<Forecast for 12 UTC, 5 November>
Intensity Very strong
Center position of probability circle N19°40' (19.7°)
E151°25' (151.4°)
Direction and speed of movement NW Slow
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 90 km (50 NM)
Storm warning area ALL 240 km (130 NM)

<Forecast for 12 UTC, 6 November>
Intensity Very strong
Center position of probability circle N22°05' (22.1°)
E151°35' (151.6°)
Direction and speed of movement N 10 km/h (6 kt)
Central pressure 940 hPa
Maximum wind speed near center 45 m/s (90 kt)
Maximum wind gust speed 65 m/s (130 kt)
Radius of probability circle 190 km (100 NM)
Storm warning area ALL 350 km (190 NM)

<Forecast for 12 UTC, 7 November>
Intensity -
Center position of probability circle N25°20' (25.3°)
E154°00' (154.0°)
Direction and speed of movement NNE 20 km/h (10 kt)
Central pressure 965 hPa
Maximum wind speed near center 40 m/s (75 kt)
Maximum wind gust speed 55 m/s (105 kt)
Radius of probability circle 330 km (180 NM)
Storm warning area ALL 440 km (240 NM)

<Forecast for 12 UTC, 8 November>
Intensity -
Center position of probability circle N29°05' (29.1°)
E159°25' (159.4°)
Direction and speed of movement NE 30 km/h (15 kt)
Central pressure 985 hPa
Maximum wind speed near center 30 m/s (55 kt)
Maximum wind gust speed 40 m/s (80 kt)
Radius of probability circle 480 km (260 NM)
Storm warning area ALL 540 km (290 NM)

<Forecast for 12 UTC, 9 November>
Intensity -
Center position of probability circle N31°35' (31.6°)
E166°20' (166.3°)
Direction and speed of movement ENE 30 km/h (16 kt)
Central pressure 992 hPa
Maximum wind speed near center 23 m/s (45 kt)
Maximum wind gust speed 35 m/s (65 kt)
Radius of probability circle 650 km (350 NM)

[Hayabusa]

24W HALONG 191104 1200 18.3N 152.8E WPAC 85 966

[aspen]

I know this has been said a quite a lot, but it must be said again: Halong continues to produce impressively deep <-85 C convection, with some areas colder than -90 C and possibly almost -100 C. An eye also appears to be in the beginning stages of formation.

https://www.weathernerds.org/satellite/ ... rnerds.png

[1900hurricane]

[Hayabusa]

thanks to that -80C+ convection, now if eye can go to the positives while maintaining that very cold convection

2019NOV04 134000 4.7 967.2 82.2 4.7 4.7 7.3 MW ON OFF OFF OFF OFF -27.80 -83.48 EYE/P -99 IR 44.8 18.65 -152.62 FCST HIM-8 25.7