WPAC: DORA - Post-Tropical - Discussion

[Hurricane Mike]

Very cool looking hurricane.

[Extratropical94]

Category 4

EP, 05, 2023080306, , BEST, 0, 151N, 1177W, 115, 952, HU

[Sciencerocks]

[cycloneye]

Hurricane Dora Discussion Number 11
NWS National Hurricane Center Miami FL EP052023
1100 PM HST Wed Aug 02 2023

Dora remains an impressive major hurricane this evening.
Geostationary satellite imagery indicates cloud top temperatures
surrounding the pinhole eye have cooled to -75 to -80 degrees C. The
initial intensity for this advisory has been increased slightly to
115 kt and is in agreement with both of the subjective Dvorak
estimates from TAFB and SAB.

The hurricane continues to move westward at 260/15 kt. A
well-established ridge to the north of the storm is expected to
maintain this general motion for the next several days. The most
recent track guidance is well-clustered and only minor adjustments
have been made to the latest official track forecast, which still
lies between the HCCA and TVCE multi-model consensus aids.

Model guidance suggests Dora is nearing its peak intensity. The
cyclone is currently over very warm waters (greater than 28 degrees
C) and in a environment with light-to-moderate vertical wind shear.
However, global models predict the wind shear will increase during
the next 24-48 h and induce a weakening trend. Between 60 h and
until the end of the forecast period, the wind shear should relax
again over the storm as it remains over warm waters (between 26-27
degrees C). The updated intensity forecast is similar to the
previous advisory prediction and shows a peak intensity of 125 kt in
12 h, which is above all model guidance. At 24 h, the forecast is
blended back into various model consensus guidance and shows gradual
weakening. Uncertainty remains high with the intensity forecast
since the compact system could be more prone to rapid intensity
fluctuations.



FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 15.0N 118.5W 115 KT 130 MPH
12H 03/1800Z 14.8N 120.8W 125 KT 145 MPH
24H 04/0600Z 14.4N 123.9W 115 KT 130 MPH
36H 04/1800Z 14.2N 127.0W 105 KT 120 MPH
48H 05/0600Z 13.8N 130.2W 90 KT 105 MPH
60H 05/1800Z 13.5N 133.3W 85 KT 100 MPH
72H 06/0600Z 13.3N 136.6W 85 KT 100 MPH
96H 07/0600Z 12.9N 143.4W 80 KT 90 MPH
120H 08/0600Z 12.9N 150.8W 75 KT 85 MPH

$$
Forecaster Bucci

[cycloneye]

An EWRC going on?

[cycloneye]

EP, 05, 2023080312, , BEST, 0, 149N, 1193W, 110, 955, HU

[Yellow Evan]

Pretty clearly sheared with convection stuck in upshear semicircle. Microwave also has an outer eyewall.

[cycloneye]

Hurricane Dora Discussion Number 12
NWS National Hurricane Center Miami FL EP052023
500 AM HST Thu Aug 03 2023

Dora's rapid intensification has ended during the past several
hours. While the eyewall cloud tops remain quite cold, the eye has
become cloud-filled and indistinct. The various subjective and
objective satellite intensity estimates have decreased a little, so
based on this the initial intensity is set at 110 kt.

The initial motion is now 265/16. As mentioned in the previous
forecast discussion, a well-established low- to mid-level ridge
north of Dora is expected to maintain this general motion for the
next several days. The track guidance remains tightly clustered in
both speed and direction, and the new forecast track, which is close
to the consensus models, has only minor adjustments from the
previous forecast.

Dora has likely peaked in intensity. While the storm is currently
over sea surface temperatures near 28C, the global model forecasts
indicate that increasing upper-level easterly winds should produce
shear during the next 36-48 h, and this is likely to cause problems
for the small inner core. Thus, the intensity forecast follows
the trend of the guidance in showing weakening during this time.
After 48 h, the shear is forecast to decrease while Dora is over
water temperatures of 26-27C. The intensity guidance during this
time shows a more gradual weakening than what is expected earlier
in the forecast period, and this part of the intensity forecast is
near or a little below the intensity consensus. Uncertainty
remains high with the intensity forecast since this compact system
could be more prone than normal to rapid intensity fluctuations.


FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 14.7N 120.1W 110 KT 125 MPH
12H 04/0000Z 14.6N 122.5W 105 KT 120 MPH
24H 04/1200Z 14.2N 125.7W 100 KT 115 MPH
36H 05/0000Z 13.9N 128.6W 90 KT 105 MPH
48H 05/1200Z 13.6N 131.6W 85 KT 100 MPH
60H 06/0000Z 13.4N 134.8W 85 KT 100 MPH
72H 06/1200Z 13.1N 138.3W 85 KT 100 MPH
96H 07/1200Z 13.0N 145.5W 80 KT 90 MPH
120H 08/1200Z 13.0N 153.0W 75 KT 85 MPH

$$
Forecaster Beven

[Kingarabian]

I think if it was a larger system with a larger anticyclone it could easily overcome the moderate easterly shear.

[Sciencerocks]

[Hurricane2022]

ERC is finishing.

[cycloneye]

 https://twitter.com/VortixWx/status/1687153518711357448

[Yellow Evan]

TXPZ21 KNES 031824
TCSENP

A. 05E (DORA)

B. 03/1800Z

C. 14.5N

D. 121.0W

E. ONE/GOES-W

F. T5.5/6.0

G. IR/EIR/VIS

H. REMARKS...LG EYE SURROUNDED BY W RING AND EMBEDDED IN B YIELDS A DT
OF 5.5. THE MET IS 5.0 BASED ON A 24HR STEADY TREND. THE PT AGREES WITH
THE DT. THE FT IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...GATLING

[cycloneye]

EP, 05, 2023080318, , BEST, 0, 145N, 1210W, 105, 958, HU

[cheezyWXguy]

Larger eye clearing out now, appearance improving

[Hayabusa]

Latest Euro has this crossing into the Western Pacific. Could this be the first since 2018's Hector?

[Sciencerocks]

[weeniepatrol]

What a cool little hurricane

[cycloneye]

Hurricane Dora Discussion Number 13
NWS National Hurricane Center Miami FL EP052023
1100 AM HST Thu Aug 03 2023

Microwave satellite data received between 12-14Z suggests that Dora
has been undergoing an eyewall replacement cycle. In addition, the
eye has been becoming more distinct during the past hour or two,
although it is not much larger than the pinhole eye seen last night.
Based on the satellite intensity estimates and the apparent
eyewall replacement, the initial intensity is set at 105 kt.

The initial motion remains 265/16 kt. As mentioned before, a
well-established low- to mid-level ridge north of Dora is expected
to maintain this general motion for the next several days. The
track guidance, while tightly clustered, has shifted a little to
the south from the previous advisory, and the forecast track is
also nudged southward. The new forecast track is close to the
various consensus models.

The latest shear estimates and forecasts suggest the expected
increase in easterly shear has not yet occurred. Based on this,
there is probably a 6-12 h window for Dora to re-intensify as the
eyewall replacement cycle ends, and the new intensity forecast
shows modest intensification during that time. After 12 h,
increased shear and slowly decreasing sea surface temperatures along
the forecast track should cause weakening through 48 h. After 48 h,
the shear is forecast to decrease while Dora is over water
temperatures of 26-27C. The intensity guidance during this time
shows a more gradual weakening than during the 12-48 h period, and
this part of the intensity forecast follows the overall trend of the
guidance. While the wind field of Dora may expand slightly due to
the eyewall replacement, it is expected to remain a compact system
that could be more prone than normal to rapid intensity
fluctuations.


FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 14.4N 121.8W 105 KT 120 MPH
12H 04/0600Z 14.1N 124.3W 110 KT 125 MPH
24H 04/1800Z 13.8N 127.4W 100 KT 115 MPH
36H 05/0600Z 13.5N 130.4W 90 KT 105 MPH
48H 05/1800Z 13.3N 133.5W 85 KT 100 MPH
60H 06/0600Z 13.0N 136.9W 85 KT 100 MPH
72H 06/1800Z 12.8N 140.4W 85 KT 100 MPH
96H 07/1800Z 12.5N 148.0W 80 KT 90 MPH
120H 08/1800Z 12.5N 155.5W 75 KT 85 MPH

$$
Forecaster Beven

[Yellow Evan]

CDO expanding and convection is rotating out of upshear. Need the eye to clear.