WPAC: DORA - Post-Tropical - Discussion

[CyclonicFury]

It's pretty crazy to think the disturbance that became Dora nearly reached tropical depression status in the Atlantic MDR, and now it appears as if there's a chance it could survive all the way to the western Pacific as a TC.

[cycloneye]

Hurricane Dora Discussion Number 15
NWS National Hurricane Center Miami FL EP052023
1100 PM HST Thu Aug 03 2023

The satellite presentation of Dora has degraded since the last
advisory. The eye is cloud filled and the outflow on the eastern
portion of the semicircle appears restricted. The initial intensity
has been lowered to a conservative 115 kt based on a blend of the T-
and CI-numbers from TAFB and SAB.

Dora is moving westward at 265/16 kt and the track forecast
reasoning is unchanged. A well-established ridge to the north of
the storm is forecast to build westward and keep Dora on the same
general trajectory for entire forecast period. The latest model
consensus has shifted slightly northward, so the new forecast lies
just north of the previous advisory prediction.

Based on the current satellite presentation, Dora may be
experiencing the effects of easterly vertical wind shear and thus,
beginning its weakening trend. Moderate shear is expected to
continue for the next 24 h and the intensity guidance suggests Dora
should continue to weaken. By 36-48 h, the shear is forecast to
decrease and the forecast track takes the hurricane over relatively
warm sea surface temperatures of 26-27 degrees C. These conditions
should allow for Dora's intensity to remain steady for a couple of
day. Additional weakening is noted by days 4 and 5, following the
overall trends in the intensity guidance, but Dora is expected to
remain a hurricane through the entire 5-day forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0900Z 14.1N 125.1W 115 KT 130 MPH
12H 04/1800Z 13.9N 127.5W 110 KT 125 MPH
24H 05/0600Z 13.7N 130.5W 100 KT 115 MPH
36H 05/1800Z 13.5N 133.7W 95 KT 110 MPH
48H 06/0600Z 13.2N 136.9W 95 KT 110 MPH
60H 06/1800Z 13.0N 140.4W 95 KT 110 MPH
72H 07/0600Z 12.8N 144.0W 95 KT 110 MPH
96H 08/0600Z 12.7N 151.7W 85 KT 100 MPH
120H 09/0600Z 13.0N 159.9W 75 KT 85 MPH

$$
Forecaster Bucci

[cycloneye]

EP, 05, 2023080412, , BEST, 0, 140N, 1261W, 105, 957, HU

[cycloneye]

Hurricane Dora Discussion Number 16
NWS National Hurricane Center Miami FL EP052023
500 AM HST Fri Aug 04 2023

Dora is experiencing some moderate easterly shear at this time.
While the cyclone continues to generate cold cloud tops in the
eyewall, the eye has become almost indistinct in infrared imagery.
In addition, recently-received SSM/IS data shows decreased
convection in the northeastern quadrant. There is a considerable
spread in the various subjective and objective satellite intensity
estimates with a range from 95-115 kt. Based on the trends since
the last advisory, the initial intensity is lowered to a somewhat
uncertain 105 kt.

The initial motion is still 265/16 kt, and the track forecast
reasoning is again unchanged from the previous advisory. A deep-
layer ridge to the north of the storm is forecast to build westward
and keep Dora on the same general trajectory for entire forecast
period. The new track guidance has changed little from the
previous advisory, and the new forecast track is an update of the
previous track.

The current shear should persist for another 24 h or so, and after
the shear lets up Dora will be moving over sea surface temperatures
of 26-27C until about 96 h. Based on these and the intensity
guidance, the intensity forecast through 96 h will show unsteady
weakening, with faster weakening during the first 24 h and around
72-96 h when Dora is closest to cold water. The intensity forecast
becomes more uncertain by 120 h. The cyclone is supposed to move
over warmer water and be in a light shear environment by that time.
However, the dynamical guidance suggests continued weakening despite
the apparently favorable environment. The 120-h forecast point
will show continued weakening in deference to the dynamical models.
It should be noted, though, that even while weakening Dora is
expected to remain a hurricane through the entire 5-day forecast
period.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 14.0N 126.9W 105 KT 120 MPH
12H 05/0000Z 13.9N 129.2W 95 KT 110 MPH
24H 05/1200Z 13.7N 132.4W 90 KT 105 MPH
36H 06/0000Z 13.5N 135.7W 90 KT 105 MPH
48H 06/1200Z 13.2N 139.1W 90 KT 105 MPH
60H 07/0000Z 13.0N 142.6W 90 KT 105 MPH
72H 07/1200Z 12.9N 146.3W 85 KT 100 MPH
96H 08/1200Z 13.0N 154.5W 80 KT 90 MPH
120H 09/1200Z 13.0N 162.0W 75 KT 85 MPH

$$
Forecaster Beven

[Sciencerocks]

[cycloneye]

EP, 05, 2023080418, , BEST, 0, 138N, 1277W, 100, 957, HU

[Sciencerocks]

[Sciencerocks]

[cycloneye]

Hurricane Dora Discussion Number 17
NWS National Hurricane Center Miami FL EP052023
1100 AM HST Fri Aug 04 2023

While there are occasional hints of an eye in visible and infrared
satellite imagery, the organization of Dora has decreased a little
since the last advisory. This is most notable in the eastern
semicircle, where the size of the central dense overcast has
diminished due to the effects of easterly shear. Satellite
intensity estimates are now in the 90-105 kt range, and the initial
intensity is reduced to a somewhat uncertain 95 kt.

This is starting to sound like a stuck record, but the initial
motion is again 265/16 kt. The track guidance and the track
forecast philosophy are again unchanged from the previous advisory,
as a deep-layer ridge to the north of the storm is forecast to build
westward and keep Dora on the same general trajectory for entire
forecast period. The new forecast track has noise-level
adjustments from the previous track.

The current shear should let up in the next 12-18 h, but until that
time Dora should continue to weaken some. After 18 h, the cyclone
should be over 26-27C sea surface temperatures, with the forecast
track taking Dora close to a patch of colder water between 72-96 h.
Based on these conditions and the intensity guidance, the new
intensity forecast calls for a little more weakening during the
first 24 h, followed by little change in strength from 24-72 h.
After 72 h, slight weakening is forecast due to the colder water
just to the north of the track. The new forecast is near the
intensity consensus through 72 h, then lies a little above the
consensus. It should be noted, though, that even while weakening
Dora is expected to remain a hurricane through the entire 5-day
forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 13.8N 128.5W 95 KT 110 MPH
12H 05/0600Z 13.6N 130.8W 90 KT 105 MPH
24H 05/1800Z 13.5N 134.0W 85 KT 100 MPH
36H 06/0600Z 13.3N 137.5W 85 KT 100 MPH
48H 06/1800Z 13.1N 141.0W 85 KT 100 MPH
60H 07/0600Z 12.9N 144.6W 85 KT 100 MPH
72H 07/1800Z 12.8N 148.4W 85 KT 100 MPH
96H 08/1800Z 12.5N 156.5W 80 KT 90 MPH
120H 09/1800Z 13.0N 164.0W 75 KT 85 MPH

$$
Forecaster Beven

[Hurricane2022]

 https://twitter.com/zeb199818/status/1687612945310855171

[cycloneye]

Yes, let's have a Hector 2018 repeat. Does anyone know how much ACE it got?

[cycloneye]

EP, 05, 2023080500, , BEST, 0, 137N, 1293W, 90, 972, HU

[Sciencerocks]

[cycloneye]

Hurricane Dora Discussion Number 18
NWS National Hurricane Center Miami FL EP052023
500 PM HST Fri Aug 04 2023

Deep convection continues to burst within Dora's eyewall, and due
to the resulting convective canopy, there have not been any hints
of an eye during the past few hours. In fact, a recent 0052 UTC
SSMIS microwave pass doesn't show an eye either, but instead a
compact curved band wrapping into the center. TAFB and SAB both
used the Dvorak embedded center pattern and provided consensus
estimates of T5.0/5.0, which closely matches the latest objective
ADT and AiDT numbers from UW-CIMSS. Dora's initial intensity is
therefore set at 90 kt.

Dora's motion remains westward at 265/16 kt. The low- to mid-level
ridge to the north of the hurricane is expected to strengthen in a
couple of days, which should result in Dora moving faster toward the
west while it passes well to the south of Hawaii early next week.
The track guidance has been tightly clustered and unwavering, and
the new NHC forecast is merely an update of the previous prediction,
lying close to a blend of the HCCA and TVCE consensus aids.

It appears that some moderate mid-level westerly shear (beneath the
outflow layer) may develop in Dora's environment in a couple of
days as a result of the strengthening low- to mid-level steering
flow. The thermodynamic environment is not ideal with (1) sea
surface temperatures along Dora's forecast path only marginally
warm at 26-27C, (2) the hurricane about to move through a more
stable environment during the next 48 hours, followed by (3) a
drier mid-level environment after 48 hours. Since the worst of
these conditions doesn't appear to overlap in time and space,
Dora's intensity is forecast to decrease gradually or be relatively
steady with some fluctuations for much of the next 5 days. The
updated NHC intensity forecast is a blend of the previous forecast
with the latest HCCA corrected-consensus model.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 13.7N 130.1W 90 KT 105 MPH
12H 05/1200Z 13.6N 132.4W 85 KT 100 MPH
24H 06/0000Z 13.4N 135.7W 80 KT 90 MPH
36H 06/1200Z 13.1N 139.1W 80 KT 90 MPH
48H 07/0000Z 12.9N 142.6W 80 KT 90 MPH
60H 07/1200Z 12.8N 146.3W 85 KT 100 MPH
72H 08/0000Z 12.7N 150.1W 85 KT 100 MPH
96H 09/0000Z 12.7N 158.1W 80 KT 90 MPH
120H 10/0000Z 13.4N 165.8W 75 KT 85 MPH

$$
Forecaster Berg

[Yellow Evan]

GFS has this being plagued by shear for the rest of its life.

[cycloneye]

Hurricane Dora Discussion Number 19
NWS National Hurricane Center Miami FL EP052023
1100 PM HST Fri Aug 04 2023

There is a hint of Dora's eye clearing once again this evening.
Since the last advisory, geostationary satellite imagery has shown
deep and persistent bursts of convection near the estimated center.
A couple of satellite microwave passes from 0241 and 0253 UTC showed
an eye open to the north. Subjective analyses from TAFB and SAB
both gave a T5.0/90 kt, however given recent satellite trends, the
initial intensity is set at 95 kt for this advisory.

The hurricane is moving westward at 16 kt along the southern
periphery of a ridge to its north. This ridge is expected to build
westward, which should induce a faster forward speed while it passes
well south of Hawaii early next week. The track guidance is still
well-clustered and the latest official track forecast is largely
unchanged.

Unlike the track model guidance, there is quite a bit of spread in
the intensity guidance. Thus, there is lower-than-normal confidence
in this prediction. Global models suggest the moderate deep-layer
vertical wind shear should decrease within 24 h, but there may
be some mid-layer shear caused by the building ridge that could
weaken Dora in a couple days. Sea surface temperatures along the
forecast track remain relatively conducive (26-27 degrees C), but
the environmental moisture gradually decreases. The latest NHC
intensity forecast is similar to the previous advisory and overall
shows some gradual weakening. However, slight fluctuations
in intensity are possible through much of the forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 13.5N 131.6W 95 KT 110 MPH
12H 05/1800Z 13.3N 134.0W 90 KT 105 MPH
24H 06/0600Z 13.2N 137.4W 85 KT 100 MPH
36H 06/1800Z 12.9N 140.8W 80 KT 90 MPH
48H 07/0600Z 12.7N 144.5W 80 KT 90 MPH
60H 07/1800Z 12.6N 148.3W 85 KT 100 MPH
72H 08/0600Z 12.5N 152.3W 85 KT 100 MPH
96H 09/0600Z 12.5N 160.2W 80 KT 90 MPH
120H 10/0600Z 13.3N 167.7W 75 KT 85 MPH

$$
Forecaster Bucci

[Hurricane2022]

 https://twitter.com/KeviShader/status/1687755319215005696



Another surprise intensification is underway!

[cycloneye]

TXPZ21 KNES 051226
TCSENP

A. 05E (DORA)

B. 05/1200Z

C. 13.4N

D. 132.5W

E. ONE/GOES-W

F. T5.5/5.5

G. IR/EIR/SWIR

H. REMARKS...A LG EYE SURROUNDED IN W AND EMBEDDED IN B YIELDS A DT OF
5.5. THE MET AGREES BASED ON SLOW DEVELOPMENT OVER 24 HOURS. THE PT ALSO
AGREES. THE FT IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...BROWN

[cycloneye]

EP, 05, 2023080512, , BEST, 0, 134N, 1325W, 95, 967, HU

[Yellow Evan]

Very curious to see how the NHC justifies retaining 95 with Dvorak and ADT supporting 10 knots higher.