WPAC: DORA - Post-Tropical - Discussion

[cycloneye]

Dora has traveled 12,000 miles since emerging from Africa.

 https://twitter.com/WxPatel/status/1688718731512344576

[Fancy1002]

It looks like it’s getting better again.

[cycloneye]

Hurricane Dora Discussion Number 31
NWS Central Pacific Hurricane Center Honolulu HI EP052023
500 PM HST Mon Aug 07 2023

Dora remains on a westward track to pass far south of Hawaii, posing
no direct threat to the islands. Satellite data shows Dora has had
little structural change in the past 12 hours, remaining a compact
and symmetric system. A recent 2317Z AMSR2 pass shows solid deep
convection surrounding the eye. A blend of the latest subjective
Dvorak estimates from PHFO, SAB and JTWC, combined with the
objective estimates from UW-CIMSS support maintaining Dora at an
initial intensity of 115 kt.

The initial motion vector is 265/20 kt. As has been the case for
several days, the track guidance remains tightly clustered through
day 3 maintaining this general trajectory, with some limited model
spread in the track beyond. The forecast track closely follows the
previous advisory, with westward movement continuing through day 3,
and then a more west-northwest track as Dora approaches the date
line.

The current environment around Dora remains largely unchanged, with
the SST of 27 C and low shear. Little change in the environment
surrounding Dora is expected in the short term, so minor
fluctuations in intensity are still possible. Beyond day 3, as the
system begins to gain latitude, SST values are expected to increase
just a bit (28-29 C). However around the same time, shear is
expected to increase. With the general consensus of the
intensity models showing weakening during this time, it would
appear the shear will be a larger contributing factor to weakening
Dora.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0300Z 12.0N 152.3W 115 KT 130 MPH
12H 08/1200Z 12.0N 155.1W 110 KT 125 MPH
24H 09/0000Z 12.0N 158.9W 105 KT 120 MPH
36H 09/1200Z 12.3N 162.7W 100 KT 115 MPH
48H 10/0000Z 12.8N 166.5W 100 KT 115 MPH
60H 10/1200Z 13.3N 170.3W 95 KT 110 MPH
72H 11/0000Z 14.2N 174.0W 95 KT 110 MPH
96H 12/0000Z 16.3N 179.5E 85 KT 100 MPH
120H 13/0000Z 18.5N 173.5E 70 KT 80 MPH

$$
Forecaster M Ballard/Birchard

[Yellow Evan]

T6.5 again. Still some debris to clear out from the older inner eyewall but making steady progress there.

[Yellow Evan]

[Kingarabian]

I think it's stronger than the CPHC's forecast atm.

[Sciencerocks]

[Yellow Evan]

[Yellow Evan]

CDO not quite what it was at main peak yet and you can see SE shear on the east. I am nitpicking here - this is the best EPAC storm I’ve tracked since Walaka.

[Astromanía]

So happy to admire this hurricane right now, remember me the times where I was looking at Hector in 2018, the first season for me in this forum

[xtyphooncyclonex]

Having tracked Hector, I think this has been the most fun EPac storm to track so far. Hoping this stays south, harmless, and resilient. Lol

This has repeatedly defied the models and NHC forecasts and that element adds to it. I'm feeling this could peak at least once more

[Yellow Evan]

 https://twitter.com/webberweather/status/1688773626378735616

[Yellow Evan]

Having tracked Hector, I think this has been the most fun EPac storm to track so far. Hoping this stays south, harmless, and resilient. Lol

This has repeatedly defied the models and NHC forecasts and that element adds to it. I'm feeling this could peak at least once more

ECMWF has low shear for 4 more days and the shear forecasts have been better than the GFS’s with Dora. I’d expect 1-2 more peaks before then, including maybe a push for T7.0 tomorrow.

[Yellow Evan]

TPPZ01 PGTW 080307

A. HURRICANE 05E (DORA)

B. 08/0230Z

C. 12.04N

D. 151.90W

E. ONE/GOES18

F. T5.0/5.0/W1.0/24HRS STT: S0.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 03A/PBO EYE/ANMTN. EYE EMBEDDED 20NM IN CDO YIELDS AN
E# OF 3.5. ADDED 0.5 FOR A WELL-DEFINED EYE AND ADDED 1.0 FOR BF TO
YIELD A DT OF 5.0. MET YIELD 4.5. PT YIELDS 5.0. DBO DT.

I. ADDITIONAL POSITIONS:
07/2312Z 12.23N 151.15W ATMS
07/2315Z 12.20N 151.03W AMS2


RAE

Vis Dvorak attempt here but that isn’t even correct.

[Yellow Evan]

TPPZ01 PGTW 080537

A. HURRICANE 05E (DORA)

B. 08/0510Z

C. 11.87N

D. 152.96W

E. ONE/GOES18

F. T5.0/5.0/W1.0/24HRS STT: S0.0/03HRS

G. IR/EIR

H. REMARKS: 01A/PBO EYE/ANMTN. WMG EYE SURROUNDED BY LG YIELDS AN
E# OF 5.0. ADDED 1.0 EYE ADJUSTMENT FOR B, TO YIELD A DT OF 6.0.
MET YIELDS 5.0. PT YIELDS 5.5. FT BASED ON MET.

I. ADDITIONAL POSITIONS: NONE


CVACH

Why use MET?

[FireRat]

Dora has traveled 12,000 miles since emerging from Africa.

https://twitter.com/WxPatel/status/1688718731512344576

Dora the Explorer!

[cycloneye]

Hurricane Dora Discussion Number 32
NWS Central Pacific Hurricane Center Honolulu HI EP052023
1100 PM HST Mon Aug 07 2023

The satellite presentation of Dora remains impressive this evening,
with the tropical cyclone continuing to display annular
characteristics. The 15 nautical mile wide eye remains very warm and
surrounded by a very cold dense overcast. Microwave imagery from
earlier this evening showed a well defined eyewall structure in
place as well. The latest subjective Dvorak current intensity
estimates from PHFO and SAB were both 6.0 (115 kt), while the
objective Dvorak ADT and AiDT estimates from UW-CIMSS were 117 kt
each. As a result, the initial intensity has been held at 115 kt for
this advisory.

Dora is moving slightly south of due west at 20 kt. This general
motion is expected to continue during the next couple days as a deep
layer ridge builds north of the Hawaiian Islands. A turn to the
west- northwest is forecast beyond day 2 as the tropical cyclone
rounds the southwestern periphery of the deep layer subtropical
ridge north of Hawaii. On this forecast track, Dora is expected to
move into the western Pacific basin late Friday. The official
forecast track was nudged southward slightly during the next couple
days due to the recent southward jog that Dora has taken and to
bring it in better alignment with the latest consensus guidance.
Beyond 48 hours, the forecast track is virtually identical to the
previous advisory.

The environmental conditions along the forecast track of Dora appear
conducive for maintaining a very intense tropical cyclone during the
next several days, with the only potential negative factor being the
surrounding dry mid-level air around the system. Given the current
annular appearance of Dora, and the fact it has appeared annular for
several days now, the dry mid-level air surrounding the storm will
likely have a difficult time being entrained into the system.
Vertical wind shear will remain low during the next 3 days, before
increasing slightly by day 4, and more substantially by day 5.
Meanwhile sea surface temperatures will change little during the
next 24 to 36 hours, remaining around 27C. Beyond 36 hours, the SSTs
will gradually increase into the 28/29C range, with ocean heat
content values rising considerably from day 2 onward. The official
intensity forecast shows a slow and gradual decrease during the next
24 hours, with the intensity then held steady through day 3. There
is the potential that Dora could strengthen again in the 48 through
72 hour time frame due to the increase in SSTs and OHC. By day 4,
vertical wind shear should begin to impact the tropical cyclone,
with a more drastic decline in intensity expected by day 5 as shear
begins to overwhelm Dora. This forecast is weighted heavily toward
the intensity consensus guidance, which has been performing much
better than the dynamical models over the last couple days.


FORECAST POSITIONS AND MAX WINDS

INIT 08/0900Z 11.7N 154.2W 115 KT 130 MPH
12H 08/1800Z 11.6N 157.2W 110 KT 125 MPH
24H 09/0600Z 11.6N 161.1W 105 KT 120 MPH
36H 09/1800Z 11.9N 164.8W 105 KT 120 MPH
48H 10/0600Z 12.5N 168.5W 105 KT 120 MPH
60H 10/1800Z 13.3N 172.2W 105 KT 120 MPH
72H 11/0600Z 14.5N 175.7W 105 KT 120 MPH
96H 12/0600Z 16.8N 178.4E 90 KT 105 MPH
120H 13/0600Z 18.5N 172.6E 60 KT 70 MPH

$$
Forecaster Jelsema

[cycloneye]

Remains at 115kt.

EP, 05, 2023080812, , BEST, 0, 115N, 1552W, 115, 953, HU

[cycloneye]

Hurricane Dora Discussion Number 33
NWS Central Pacific Hurricane Center Honolulu HI EP052023
500 AM HST Tue Aug 08 2023

Dora remains a powerful hurricane early this morning, with the
tropical cyclone continuing to display annular characteristics. The
eye has cooled slightly since the previous advisory, but it
continues to be surrounded by a very cold dense overcast. The latest
subjective Dvorak current intensity estimates from PHFO and SAB were
both 6.0 (115 kt). Meanwhile, the objective Dvorak ADT and AiDT
estimates from UW-CIMSS were both 112 kt. Using a blend of these
data the initial intensity has been held at 115 kt for this
advisory.

Dora is moving slightly south of due west at 19 kt. This general
motion is expected to continue during the next couple days as a deep
layer ridge builds north of the Hawaiian Islands. A turn to the
west- northwest is forecast beyond day 2 as the tropical cyclone
rounds the southwestern periphery of the deep layer subtropical
ridge north of Hawaii. On this forecast track, Dora is expected to
move into the western Pacific basin Friday. The official forecast
track is essentially the same as the previous advisory, and closely
aligns with a blend of the consensus and reliable dynamical
guidance.

The environmental conditions along the forecast track of Dora appear
conducive for maintaining a very intense tropical cyclone during the
next several days, with the only potential negative factor being the
surrounding dry mid-level air. Given the persistent annular
appearance of Dora during the past several days, the dry mid-level
air will likely have a difficult time being entrained into the
system. Vertical wind shear will remain low during the next 3 days,
before increasing considerably by days 4 and 5. Meanwhile sea
surface temperatures will change little during the next 24 hours,
remaining around 27C. Beyond 24 hours however, the SSTs will
gradually increase into the 28/29C range, with ocean heat content
values rising beyond 36 hours as well. The official intensity
forecast shows a slow and gradual decrease during the next 24 hours,
with the intensity then held steady through 60 hours. There is the
potential that Dora could re-intensify in the 36 through 60 hour
time frame due to the increase in SSTs and OHC, however this is not
shown in the intensity forecast. By day 3, vertical wind shear
should begin to impact the tropical cyclone, with a more drastic
decline in intensity expected for days 4 and 5 as shear begins to
overwhelm Dora. This forecast is weighted heavily toward the
intensity consensus guidance through day 3, then trends toward a
blend of the consensus and dynamical guidance for days 4 and 5.


FORECAST POSITIONS AND MAX WINDS

INIT 08/1500Z 11.5N 156.1W 115 KT 130 MPH
12H 09/0000Z 11.4N 159.1W 110 KT 125 MPH
24H 09/1200Z 11.5N 163.0W 105 KT 120 MPH
36H 10/0000Z 11.9N 166.8W 105 KT 120 MPH
48H 10/1200Z 12.5N 170.4W 105 KT 120 MPH
60H 11/0000Z 13.5N 173.9W 105 KT 120 MPH
72H 11/1200Z 14.7N 177.1W 100 KT 115 MPH
96H 12/1200Z 16.9N 177.0E 65 KT 75 MPH
120H 13/1200Z 18.5N 171.5E 45 KT 50 MPH

$$
Forecaster Jelsema

[Sciencerocks]