SPAC: HAROLD - Post-Tropical

[Nancy Smar]

90P INVEST 200331 0600 8.5S 154.3E SHEM 20 1004

[Nancy Smar]

IDQ20018
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - EASTERN REGION
Issued by BRISBANE TROPICAL CYCLONE WARNING CENTRE
at: 1338 UTC 02/04/2020
Name: Tropical Cyclone Harold
Identifier: 12U
Data At: 1200 UTC
Latitude: 10.0S
Longitude: 157.8E
Location Accuracy: within 30 nm [55 km]
Movement Towards: east southeast [113 deg]
Speed of Movement: 8 knots [14 km/h]
Maximum 10-Minute Wind: 35 knots [65 km/h]
Maximum 3-Second Wind Gust: 50 knots [95 km/h]
Central Pressure: 999 hPa
Radius of 34-knot winds NE quadrant: 80 nm [150 km]
Radius of 34-knot winds SE quadrant: 80 nm [150 km]
Radius of 34-knot winds SW quadrant: 60 nm [110 km]
Radius of 34-knot winds NW quadrant: 80 nm [150 km]
Radius of Maximum Winds: 20 nm [35 km]
Dvorak Intensity Code: T2.5/3.0/D1.0/24HRS
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 130 nm [240 km]
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+06: 02/1800: 10.4S 158.8E: 040 [080]: 035 [065]: 999
+12: 03/0000: 11.1S 159.9E: 055 [100]: 040 [075]: 997
+18: 03/0600: 11.7S 160.9E: 065 [125]: 050 [095]: 991
+24: 03/1200: 12.3S 161.8E: 080 [145]: 060 [110]: 983
+36: 04/0000: 13.5S 163.1E: 100 [180]: 080 [150]: 967
+48: 04/1200: 14.2S 164.1E: 120 [220]: 085 [155]: 961
+60: 05/0000: 14.8S 164.7E: 140 [255]: 085 [155]: 960
+72: 05/1200: 15.2S 165.4E: 155 [290]: 085 [155]: 960
+96: 06/1200: 16.1S 168.0E: 200 [370]: 085 [155]: 962
+120: 07/1200: 17.9S 172.8E: 290 [535]: 085 [155]: 964
REMARKS:
The system showed rapid development during the afternoon hours earlier today,
which has since been a little more restricted over the last six hours as
convection reorganises around the centre. Confidence in the centre location is
high with assistance of recent scatterometry.

Curved band has become more difficult to discern in the past few hours, however
an average wrap of 0.5 is just about possible to assign yielding a DT of 2.5.
Using a shear pattern with centre displaced from convection to the SE also yieds
DT 2.5. MET is 2.0 and PT 2.5 FT set to 2.5, with CI maintained at 3.0.

The system is being steered towards the southeast by a weak upper low to the
south. A slight curve to the south is likely from late Friday as the upper low
weakens and the mid level ridge to the east builds a little. These features are
likely to weaken over the weekend, with the motion of the cyclone becoming
significantly slower, before a new upper torugh developing and moving east over
the Tasman Sea leads to a renewed acceleration to the southeast.

TC Harold will remain in a very favourable environment for intensification over
the next 48 hours, within an area of weak vertical shear underneath an upper
ridge, excellent upper outflow both poleward and equatorward, and over SSTs of
around 30 degrees celsius. Statistical RI guidance is extremely favourable for a
period of rapid intensification in the next 24 to 36 hours. The forecast calls
for intensification at a greater than climatological rate over this period,
followed by a plateauing early next week when proximity to the upper trough may
begin to inhibit further intensification of the system as vertical shear
increases. It should be noted that development at an even faster rate than
forecast is possible, which could bring the system to category 4 or above near
the central islands of Vanuatu.



Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 02/1930 UTC by Brisbane
TCWC.

[aspen]

Looks like we might finally see a major hurricane equivalent system in the Southern Hemisphere this year. It’s already looking a lot better than any other South Pacific cyclone, with outflow in all quadrants and a tight, compact structure. Every other cyclone so far has had such a broad circulation, limiting then to Cat 1 intensity at the most.

[aspen]

RI might be about to commence. Diurnal max has begun, and Harold already has excellent outflow and a good CDO, which seems to be trying to curve around the center some more. SSTs and OHC in its path are high enough to support a Cat 4 or above storm.

[galaxy401]

This cyclone is already deadly. A boat carrying up to 60 people went missing when it sailed into the storm.

[aspen]

It’s taking awfully long to get an eye going. SSTs and outflow are still great, and I haven’t spotted any signs of dry air intrusion. Maybe there’s some shear at certain levels, but since microwave imagery has been running behind all day, I can’t tell.

[Kingarabian]

It’s taking awfully long to get an eye going. SSTs and outflow are still great, and I haven’t spotted any signs of dry air intrusion. Maybe there’s some shear at certain levels, but since microwave imagery has been running behind all day, I can’t tell.

It's trying to RI right now. Or probably going through the phase now.

[aspen]

It’s taking awfully long to get an eye going. SSTs and outflow are still great, and I haven’t spotted any signs of dry air intrusion. Maybe there’s some shear at certain levels, but since microwave imagery has been running behind all day, I can’t tell.

It's trying to RI right now. Or probably going through the phase now.

Looks like it. The eye is trying to clear, and might end up being on the small side.

[cycloneye]

 https://twitter.com/StormBarretto/status/1246202127581687810

[aspen]

The latest microwave pass shows a completed eyewall. While small, it doesn’t appear to be a pinhole.
https://rammb-data.cira.colostate.edu/t ... 031840.gif

[Kingarabian]

The latest microwave pass shows a completed eyewall. While small, it doesn’t appear to be a pinhole.
https://rammb-data.cira.colostate.edu/t ... 031840.gif

Yeah just bigger than a pinhole eye.

[Highteeld]

[Kingarabian]

 https://twitter.com/webberweather/status/1246201760743665666

[aspen]

https://twitter.com/webberweather/status/1246201760743665666

To be fair, the eye popped out between advisories. If they go with something under 70 kt, or say it’s not >100 kt once the eye fully clears, then we’ll have a problem.

[aspen]

It’s probably at 100-115 kt now (possibly higher), but the JTWC is going to put Harold at 75-85 kt. I’m calling it now.

[Highteeld]

Nowhere near 60 knots haha

[aspen]

Nowhere near 60 knots haha

https://i.imgur.com/GSgVQph.jpg

Easy Cat 4 right there, but Dvorak says 75-80 kt, so that’s what the JTWC is going to go with.

I wonder how little they’re going to try this year. Honestly, you can’t do much worse without intentionally trying to suck.

EDIT: I just remembered how they put 130-140 kt Cyclone Ambali as a 100 kt Cat 3 a couple of months ago. I sense a repeat here.

[aspen]

JTWC put Harold at 90 kt. I think that’s worthy of getting out the pitchforks and torches...

[Kingarabian]

This is a major hurricane lol.

[1900hurricane]

Hey, the SHem did a thing.