CPAC: DARBY - Post-Tropical

[Kingarabian]

...DARBY UNEXPECTEDLY BECOMES A MAJOR HURRICANE...

[TheStormExpert]

...DARBY UNEXPECTEDLY BECOMES A MAJOR HURRICANE...

Nothing happens "UNEXPECTEDLY" these days in the East Pacific.

[Ntxw]

She's been a tenacious little storm fighting off constantly deterrents..

[CrazyC83]

Given that Danny was 110 kt in a similar setup, that seems like my best guess.

[cycloneye]

The Darbys like to be strong.

 https://twitter.com/philklotzbach/status/754464848793047040

[Kingarabian]

[Yellow Evan]

Cloud tops are warming and Darby is become less symmetrical. This has peaked for good.

[cycloneye]

HURRICANE DARBY DISCUSSION NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016
800 PM PDT SAT JUL 16 2016

Darby has finally responded to the cooler SSTs, with a weakening in
the central convection and the eye becoming less distinct. The
current intensity is reduced to 90 kt which is a blend of Data-T
and Current Intensity numbers. The cyclone is expected to
traverse ocean waters of near 25 deg C, along the northern edge of
the strong gradient of SST, for the next few days. Even though the
shear is forecast to remain low for the next 2-3 days, the
combination of cooler waters and a more stable air mass should
result in continued weakening. Near the end of the forecast period,
the SSTs under Darby will begin to warm a bit. By that time,
however, increasing west-southwesterly shear should prevent
restrengthening.

Center fixes are in good agreement, which is not surprising given
that an eye has been apparent, and the initial motion continues at
285/9 kt. A narrow mid-level subtropical ridge to the north of
Darby is expected to remain in place for the next several days.
This steering pattern should cause the tropical cyclone to move on a
mainly westward heading for the next 4 days or so. By the end of
the forecast period, the weakening system should be steered more by
the low-level tradewind flow, and turn to a slightly south of
westward heading. The official track forecast is very close to the
previous one, and is a blend of the latest GFS and ECMWF solutions.

A drifting buoy, ID 46906, near the southern eyewall of Darby,
measured a pressure of 980.1 mb around 0200 UTC.

FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 18.2N 125.8W 90 KT 105 MPH
12H 17/1200Z 18.4N 127.2W 85 KT 100 MPH
24H 18/0000Z 18.7N 129.1W 75 KT 85 MPH
36H 18/1200Z 18.9N 131.2W 65 KT 75 MPH
48H 19/0000Z 19.1N 133.2W 55 KT 65 MPH
72H 20/0000Z 19.8N 138.0W 45 KT 50 MPH
96H 21/0000Z 19.6N 142.5W 40 KT 45 MPH
120H 22/0000Z 18.5N 147.5W 35 KT 40 MPH

$$
Forecaster Pasch

[1900hurricane]

Yeah, looks like the colder water is starting to get to it. Darby did finally manage to shut the dry air out today though, likely giving it the brief window to intensify to a category 3.

[HurricaneRyan]

Similar to 2010's Darby.

I thought Darby was a male name though.

[Kingarabian]

So Euro has an Iselle-esque landfall.

[stormwise]

If Darby gets to 135W @TS intensity may see another resurrection.

[cycloneye]

HURRICANE DARBY DISCUSSION NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016
200 AM PDT SUN JUL 17 2016

Darby appears to be gradually weakening. Although the annular
hurricane still has a well organized cloud pattern and distinct eye,
the cloud tops in the eyewall have warmed during the last several
hours. The initial intensity for this advisory is lowered a little
to 85 kt. This intensity estimate is based on a blend of the Dvorak
Final T- and CI-numbers from TAFB, SAB, and CIMSS at the University
of Wisconsin. The hurricane is currently over cool, 25 deg C waters
and embedded in a fairly stable air mass. Since Darby is expected
to move over even cooler water and into a drier air mass during the
next couple of days, steady weakening is predicted. After that time,
Darby will likely track over slightly warmer water, but it will also
be moving into an environment of increasing westerly shear, which
should allow for some continued weakening. The NHC intensity
forecast is similar to the previous one and is in good agreement
with the intensity model consensus.

The hurricane is moving westward, or 280 degrees, at 8 kt. This
general heading with a slight increase in forward speed is expected
during the next few days as mid-level ridging remains in place to
the north of the tropical cyclone. Beyond that time, a motion
slightly south of due west is forecast when the shallower system is
steered by the low- to mid-level flow. The NHC official track
forecast is nudged to the north of the previous one to come in line
with the latest consensus of the GFS and ECMWF models.

FORECAST POSITIONS AND MAX WINDS

INIT 17/0900Z 18.2N 126.6W 85 KT 100 MPH
12H 17/1800Z 18.3N 128.0W 75 KT 85 MPH
24H 18/0600Z 18.6N 130.0W 65 KT 75 MPH
36H 18/1800Z 19.0N 132.1W 60 KT 70 MPH
48H 19/0600Z 19.4N 134.4W 50 KT 60 MPH
72H 20/0600Z 20.1N 139.0W 45 KT 50 MPH
96H 21/0600Z 19.8N 143.8W 40 KT 45 MPH
120H 22/0600Z 18.9N 148.5W 35 KT 40 MPH

$$
Forecaster Cangialosi

[cycloneye]

HURRICANE DARBY DISCUSSION NUMBER 24
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016
800 AM PDT SUN JUL 17 2016

Darby's satellite presentation has changed very little since the
last advisory. The hurricane still has a well-defined 10 n mi wide
eye and a symmetric central dense overcast with cloud tops as cold
as -68C. The initial intensity is held at 85 kt based on a blend
of the latest Dvorak Current Intensity numbers, which are 5.0/90 kt
from TAFB and SAB and 4.7/82 kt from the UW-CIMSS ADT.

A narrow subtropical ridge lies to the north of the hurricane along
30N, which is steering Darby westward, or 280/8 kt. A westward or
west-northwestward motion is expected during the next four days due
to the position and strength of the ridge, and the track guidance
is in excellent agreement during this period. By day 5, a weaker
Darby is forecast to turn west-southwestward due to strong
low-level ridging north of the Hawaiian Islands. There is a little
more spread among the track models at the end of the forecast
period, but the GFS, ECMWF, and UKMET are all south of the TVCE
multi-model consensus. The updated forecast therefore remains
south of TVCE and is a little faster than the previous forecast on
day 5.

Darby is now over SSTs between 24 and 25C and is expected to move
over even colder waters in 12-24 hours. Therefore, fairly quick
weakening is forecast in the short term, and Darby is likely to lose
hurricane strength on Monday. SSTs are actually expected to begin
increasing again after 24 hours, which could slow the rate of
weakening through the end of the forecast period. However,
increasing vertical shear and a drier mid-level air mass by days 4
and 5 will likely prevent significant re-intensification over the
warmer waters to the southeast of Hawaii. The NHC intensity
forecast is near the SHIPS model through day 3 and then a little
higher than SHIPS on days 4 and 5, closer to the ICON intensity
consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 17/1500Z 18.3N 127.4W 85 KT 100 MPH
12H 18/0000Z 18.4N 128.8W 75 KT 85 MPH
24H 18/1200Z 18.8N 130.9W 65 KT 75 MPH
36H 19/0000Z 19.3N 133.1W 55 KT 65 MPH
48H 19/1200Z 19.7N 135.4W 50 KT 60 MPH
72H 20/1200Z 20.1N 140.2W 40 KT 45 MPH
96H 21/1200Z 19.5N 145.0W 35 KT 40 MPH
120H 22/1200Z 18.5N 150.0W 35 KT 40 MPH

$$
Forecaster Berg

[Kingarabian]

Real test begins today:

[Kingarabian]

00z GFS into the big Island as a weak tropical storm.

[Yellow Evan]

Code: Select all

EP, 05, 2016071718,   , BEST,   0, 183N, 1278W,  80,  978, HU,  34, NEQ,  100,   70,   60,   90, 1010,  240,  15,   0,   0,   E,   0,    ,   0,   0,      DARBY, D,  0,    ,    0,    0,    0,    0, genesis-num, 011,

[Alyono]

12Z EC has a narrow miss of the big island from a hurricane

[cycloneye]

HURRICANE DARBY DISCUSSION NUMBER 25
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016
200 PM PDT SUN JUL 17 2016

Darby's eye has filled in during the day, and microwave data
indicate that the eyewall has opened up on its southeastern side.
Dvorak estimates are slowly coming down, and the initial intensity
is lowered to 80 kt based on Dvorak Current Intensity numbers which
range from 77-90 kt from SAB, TAFB, and UW-CIMSS ADT. The center
of Darby is approaching the 24C SST isotherm, and it should reach
waters around 23C in about 12 hours. After that time, SSTs will
slowly warm up to between 26-27C by the end of the forecast period.
Vertical shear is expected to remain low for another 2-3 days and
then increase to around 20 kt from the west by day 5. Considering
all these factors, fairly quick weakening is expected during the
next 24 hours while Darby is over the coldest water, followed by
more gradual weakening through day 5. The NHC intensity forecast
closely follows the ICON intensity consensus for the entire forecast
period, and Darby is likely to weaken to a tropical storm in about
24 hours.

The initial motion is 275/8 kt. Darby is expected to gain some
latitude through day 3 and then lose latitude on days 4 and 5, but
the ridge to the north should maintain the cyclone on a general
westward heading for the entire forecast period. The track guidance
remains tightly clustered with no noteworthy shifts in the overall
envelope on this forecast cycle. The updated NHC forecast is
therefore very similar to the previous one and is close to a
consensus of the GFS and ECMWF models.

FORECAST POSITIONS AND MAX WINDS

INIT 17/2100Z 18.3N 128.3W 80 KT 90 MPH
12H 18/0600Z 18.5N 129.9W 70 KT 80 MPH
24H 18/1800Z 18.8N 132.0W 60 KT 70 MPH
36H 19/0600Z 19.2N 134.4W 55 KT 65 MPH
48H 19/1800Z 19.6N 136.7W 50 KT 60 MPH
72H 20/1800Z 19.8N 141.4W 40 KT 45 MPH
96H 21/1800Z 19.0N 146.0W 35 KT 40 MPH
120H 22/1800Z 18.0N 150.5W 35 KT 40 MPH

$$
Forecaster Berg

[Kingarabian]

Doing better the last few frames.