EPAC: CELIA - Post-Tropical

[Alyono]

MU south this run

[1900hurricane]

Interesting to see the old eyewall still spinning around in there.



Also for once, there's more good microwave passes recently than I even know what to do with.

[stormwise]

[cycloneye]

HURRICANE CELIA DISCUSSION NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
200 AM PDT TUE JUL 12 2016

The cloud pattern of Celia has changed somewhat, as the hurricane
appears to be completing an eyewall replacement cycle. A 50-60 n mi
wide eye now is embedded in a relatively small central dense
overcast, which gives Celia a somewhat annular appearance.
Subjective and objective satellite estimates have changed little
since the past advisory, so the initial intensity remains 85 kt.

Celia has continued to turn to the right and the initial motion is
now 300/9. The hurricane is near the western periphery of a
mid-tropospheric subtropical ridge, and a northwestward motion is
likely for the next couple of days. A mid-level cyclone seen in
water vapor imagery near 29N 151W is expected to weaken to a trough
and move northward after 24-48 hours, which would allow a ridge to
build back in to the north of the tropical cyclone. This
development would steer Celia in a more westerly direction in the
later part of the forecast period. The tightly clustered track
models have again shifted a little northward from their previous
predictions, and the official forecast shows a similar small shift.
The new forecast track lies near the various consensus models in
the middle of the guidance envelope.

Celia should be moving over decreasing sea surface temperatures for
the next several days, and the dynamical models forecast increasing
northwesterly shear after 48 hours. This combination should cause
Celia to weaken, and all of the intensity guidance supports this
scenario. The new intensity forecast remains in best agreement with
the intensity consensus IVCN.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 16.2N 127.9W 85 KT 100 MPH
12H 12/1800Z 17.0N 129.2W 80 KT 90 MPH
24H 13/0600Z 18.2N 131.1W 70 KT 80 MPH
36H 13/1800Z 19.4N 133.1W 60 KT 70 MPH
48H 14/0600Z 20.4N 135.2W 50 KT 60 MPH
72H 15/0600Z 22.0N 139.5W 40 KT 45 MPH
96H 16/0600Z 22.5N 144.0W 35 KT 40 MPH
120H 17/0600Z 23.0N 148.5W 30 KT 35 MPH

$$
Forecaster Beven

[cycloneye]

 https://twitter.com/EricBlake12/status/752790569785655296

[cycloneye]

HURRICANE CELIA DISCUSSION NUMBER 24
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
800 AM PDT TUE JUL 12 2016

Although the cloud pattern remains well organized, the convection
has weakened considerably during the past several hours while the
circulation moves over cooler waters. The eye, or what is left
of it, has become large and ragged with the deepest convection
located within a curved band to the east. Given that the numbers
from both TAFB and SAB have decreased to 4.0 on the Dvorak scale,
the initial intensity is lowered to 80 kt, which is an intensity
higher than one can expect from these numbers. However, due to
continuity and Dvorak constraints, this is probably a good estimate
at this time.

Celia is moving toward increasingly cooler waters, and beyond 2
days, the shear is expected to increase. These two factors should
result in weakening. Most of the models call for gradual weakening
and so does the NHC forecast, which in fact, is very close to the
SHIPS model.

Celia is now moving toward the northwest at 10 kt around the
subtropical ridge. Global models forecast the ridge to amplify a
little, and this could force Celia on a more west-northwesterly
track later today or Wednesday. By the end of the forecast period,
Celia should have become a shallow cyclone, and will likely move on
a westward track steered by the low-level flow. The NHC forecast is
very near the multi-model consensus and continues to be very
similar to the previous forecast. Since the track guidance is in
good agreement, there is high confidence in the forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 12/1500Z 16.8N 128.5W 80 KT 90 MPH
12H 13/0000Z 17.8N 129.9W 70 KT 80 MPH
24H 13/1200Z 18.9N 131.8W 60 KT 70 MPH
36H 14/0000Z 19.9N 133.8W 50 KT 60 MPH
48H 14/1200Z 21.0N 136.0W 40 KT 45 MPH
72H 15/1200Z 22.1N 140.2W 30 KT 35 MPH
96H 16/1200Z 22.5N 145.0W 25 KT 30 MPH
120H 17/1200Z 23.5N 149.5W 25 KT 30 MPH

$$
Forecaster Avila

[alan1961]

Hurricane Celia from ISS





Large outer band stretching way out

[Alyono]

I strongly disagree with the lowering of the winds to 70 kts. The eye remains very well defined and cloud tops have cooled significantly to the west of the center. TAFB has a 4.0/4.0. I'm not seeing anything less than a 4.5 myself

Not a big deal as this is in the middle of nowehere

[cycloneye]

HURRICANE CELIA DISCUSSION NUMBER 25
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
200 PM PDT TUE JUL 12 2016

The cloud pattern consists of a large ragged eye surrounded by a
ring of moderate convection and a convective curved band to the
east of the eye. The overall amount of convection has been
decreasing during the past 12 hours. The Dvorak T-numbers have
decreased slightly during the day, and the best estimate of the
current intensity is 70 kt. The circulation of Celia has continued
to move over increasingly cooler waters, and SHIPS guidance
indicates a gradual increase in shear. On this basis, the NHC
forecast calls for weakening, and Celia is forecast to be a tropical
depression in about 3 days or sooner.

The best estimate of the initial motion is toward the west-northwest
or 300 degrees at about 11 kt. Global models continue to show a
persistent moderate subtropical ridge north of Celia. This pattern
will continue to steer the cyclone on a west-northwesterly track
for the next 2 to 3 days. After that time, Celia should have become
a shallow cyclone, and will likely move on a westward track steered
by the low-level flow. The track guidance continues to be in very
good agreement, and there is high confidence in the forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 12/2100Z 17.4N 129.5W 70 KT 80 MPH
12H 13/0600Z 18.4N 130.9W 65 KT 75 MPH
24H 13/1800Z 19.6N 133.0W 55 KT 65 MPH
36H 14/0600Z 20.5N 135.2W 45 KT 50 MPH
48H 14/1800Z 21.3N 137.0W 35 KT 40 MPH
72H 15/1800Z 22.5N 141.5W 30 KT 35 MPH
96H 16/1800Z 23.0N 146.0W 25 KT 30 MPH
120H 17/1800Z 24.0N 150.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Avila

[stormwise]

[Kingarabian]

GFS hurts itself when it keeps forecasting Cat. 2 storms intensifying over 23-24C water. But looks like it did a good job with the steering pattern.

[Kingarabian]

Holding its own as it enters 25C waters.

[cycloneye]

HURRICANE CELIA DISCUSSION NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
800 PM PDT TUE JUL 12 2016

The convective cloud tops surrounding the large ragged eye of Celia
have been gradually warming since earlier today. Based on
subjective Dvorak classifications from both TAFB and SAB as well as
objective ADT estimates from UW-CIMSS, the intensity is reduced to
65 kt. Since the tropical cyclone will be moving over cooler
waters, into a stabler air mass, and westerly shear is forecast to
increase, a continued weakening trend is expected. Celia should
weaken into a tropical depression by the time it reaches the
Central Pacific Hurricane Basin. The official intensity forecast
is a little below the latest model consensus and a little above the
latest LGEM guidance.

The large eye has been moving between west-northwest and northwest
at around 10 kt. There is no reason to make any significant
changes to the previous NHC forecast track. A mid-level
subtropical ridge is predicted by the global models to remain to
the north of the cyclone for the next several days. Celia is
likely to become an increasingly shallow system, so later in the
forecast period, it should turn toward the west following the
low-level flow. The official forecast is close to the consensus of
the dynamical guidance, which are fairly tightly clustered. This
is basically an extension/update of the previous NHC track.

FORECAST POSITIONS AND MAX WINDS

INIT 13/0300Z 18.0N 130.3W 65 KT 75 MPH
12H 13/1200Z 18.9N 131.8W 60 KT 70 MPH
24H 14/0000Z 20.0N 133.9W 50 KT 60 MPH
36H 14/1200Z 21.0N 135.9W 45 KT 50 MPH
48H 15/0000Z 21.9N 138.1W 35 KT 40 MPH
72H 16/0000Z 22.7N 142.6W 30 KT 35 MPH
96H 17/0000Z 23.5N 147.5W 25 KT 30 MPH
120H 18/0000Z 24.0N 152.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Pasch

[Kingarabian]

Looks like rapid weakening is about to ensue.

[cycloneye]

TROPICAL STORM CELIA DISCUSSION NUMBER 27
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
200 AM PDT WED JUL 13 2016

While Celia continues to show an eye in infrared imagery, several
recent microwave overpasses indicate this feature is displaced to
the north-northeast of the low-level center. Satellite intensity
estimates from TAFB and SAB are 65 kt, and a recent CIMSS AMSU
estimate is 74 kt. However, a partial ASCAT-B overpass showed
maximum winds of 55 kt north of the center. Given these data and
the level of disorganization implied by the microwave imagery,
Celia is downgraded to a tropical storm with 60-kt winds.

The initial motion is 300/10. A mid-level subtropical ridge is
predicted by the global models to remain to the north of the cyclone
for the next several days. This should result in Celia moving
west-northwestward for the next 36-48 hours. After that time, the
guidance becomes somewhat divergent. The GFS and UKMET models are
on the south side of the guidance envelope and forecast a more
westward motion, while the ECMWF is on the north side and forecasts
a continued west-northwestward motion. Overall, the consensus
models have shifted a little to the south after 36 hours. Based on
this, the new forecast track is also shifted a little to the south
and shows a just north of due west motion from 48-120 hours.

Celia should encounter decreasing sea surface temperatures for the
next 48-72 hours. After 72 hours, the cyclone is likely to
encounter strong westerly shear even as it moves over slightly
warmer water. This evolution should cause Celia to weaken further,
with the system forecast to become a tropical depression by 72 hours
and a remnant low by 120 hours. The new forecast intensity is an
update of the previous forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 13/0900Z 18.3N 131.2W 60 KT 70 MPH
12H 13/1800Z 19.3N 132.7W 55 KT 65 MPH
24H 14/0600Z 20.4N 134.8W 50 KT 60 MPH
36H 14/1800Z 21.3N 136.9W 40 KT 45 MPH
48H 15/0600Z 22.0N 139.0W 35 KT 40 MPH
72H 16/0600Z 22.5N 144.0W 30 KT 35 MPH
96H 17/0600Z 23.0N 149.0W 25 KT 30 MPH
120H 18/0600Z 23.5N 153.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

[cycloneye]

TROPICAL STORM CELIA DISCUSSION NUMBER 28
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
800 AM PDT WED JUL 13 2016

The cloud pattern is gradually deteriorating, and deep convection
is confined to a small area near the center. Microwave and
conventional infrared images continue to show that the low- and
mid-level centers are not vertically aligned, which is another
indication of weakening. In addition, subjective Dvorak estimates
from TAFB and SAB, as well as objective numbers from CIMMS, argue
for a reduction of the winds. Therefore, the initial intensity is
set at 55 kt.

Celia is already over cooler waters, and the wind shear is forecast
to gradually increase. The presence of these conditions will
result in weakening, and Celia is expected to degenerate into a
tropical depression in a couple of days or sooner and into a remnant
low thereafter. The NHC forecast follows the trend of the SHIPS
guidance and the intensity model consensus.

The cyclone appears to be moving toward the northwest or 305 degrees
at 10 kt around the periphery of the subtropical ridge. Given that
Celia is forecast to weaken and become a shallow system, the cyclone
most likely will move toward the west in a couple of days steered by
the prevailing low-level easterly flow. All track models are tightly
clustered, and the NHC forecast, which is similar to the previous
one, is in the middle of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 13/1500Z 19.1N 132.6W 55 KT 65 MPH
12H 14/0000Z 19.8N 134.0W 45 KT 50 MPH
24H 14/1200Z 20.8N 136.1W 40 KT 45 MPH
36H 15/0000Z 21.7N 138.0W 35 KT 40 MPH
48H 15/1200Z 22.0N 140.3W 30 KT 35 MPH
72H 16/1200Z 23.0N 145.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 17/1200Z 23.5N 150.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 18/1200Z 24.0N 154.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Avila

[cycloneye]

TROPICAL STORM CELIA DISCUSSION NUMBER 29
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
200 PM PDT WED JUL 13 2016

Deep convection associated with Celia has practically vanished, and
consequently the Dvorak subjective and objective T-numbers have
continued to decrease. However, the cyclone still has a vigorous
circulation, and the best estimate of the initial intensity is 45
kt.

The circulation of Celia is moving over waters of about 24 degree
Celsius and cooling, while the wind shear is forecast to gradually
increase. These conditions will result in additional weakening, and
Celia is expected to degenerate into a tropical depression in about
a day, and into a remnant low soon thereafter. The NHC forecast
is following SHIPS guidance.

The cyclone appears to be moving toward the west-northwest or 300
degrees at 11 kt around the periphery of the subtropical ridge.
Given that Celia is already weakening and becoming a shallow
system, it will be steered by the low-level flow on a general
west to west-northwest track for the next several days until
dissipation.

FORECAST POSITIONS AND MAX WINDS

INIT 13/2100Z 19.5N 133.8W 45 KT 50 MPH
12H 14/0600Z 20.3N 135.4W 40 KT 45 MPH
24H 14/1800Z 21.2N 137.5W 30 KT 35 MPH
36H 15/0600Z 21.7N 139.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 15/1800Z 22.0N 142.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 16/1800Z 22.5N 147.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 17/1800Z 23.5N 151.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 18/1800Z 24.0N 156.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Avila

[cycloneye]

TROPICAL STORM CELIA DISCUSSION NUMBER 30
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
800 PM PDT WED JUL 13 2016

After Celia was nearly devoid of deep convection earlier today,
infrared satellite images indicate that convection has made a bit of
comeback over the northern portion of the circulation. The initial
intensity is being held at 45 kt, which is in agreement with the
Dvorak classifications from TAFB and SAB, and a partial ASCAT-B pass
from a few hours ago.

Celia is currently over cool 24 C waters, and although the waters
could warm a little along the forecast track, they are expected to
stay below 26 C. In addition, the tropical cyclone will be moving
into an environment of increasing westerly shear and drier air.
These conditions should cause weakening, and the official forecast
shows Celia degenerating into a remnant low by 36 hours. The global
models suggest that the remnant low could persist for several days
over the central Pacific.

The tropical storm is moving west-northwestward at 11 kt, and is
being steered on the southwestern periphery of a sprawling mid-level
ridge centered over northern Mexico and the southern United States.
A westward turn is expected in a day or two, when Celia becomes a
shallow system and is steered by the low-level trade wind flow. The
models are tightly clustered, and the NHC official track forecast
lies near the middle of the guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 14/0300Z 19.9N 134.7W 45 KT 50 MPH
12H 14/1200Z 20.8N 136.3W 40 KT 45 MPH
24H 15/0000Z 21.5N 138.4W 30 KT 35 MPH
36H 15/1200Z 21.9N 140.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 16/0000Z 22.2N 143.2W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 17/0000Z 22.9N 148.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 18/0000Z 23.6N 152.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 19/0000Z 24.5N 157.0W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

[Kingarabian]

000
WTPZ44 KNHC 140901
TCDEP4

TROPICAL STORM CELIA DISCUSSION NUMBER 31
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
200 AM PDT THU JUL 14 2016

Although conventional satellite imagery indicates some decrease in
overall deep convection coverage this morning, a 0558 UTC ASCAT
overpass revealed numerous 45 kt winds over the northern half of the
system. West-southwesterly shear appears to be undercutting the
upper easterly diffluent flow aloft, subsequently, creating a
structural tilt and displacing the circulation center to the
south of the convective mass. The initial intensity is held at 45
kt based on the aforementioned scatterometer pass. Celia is
traversing gradually decreasing sea surface temperatures, and the
large-scale models all indicate that the cyclone will encounter
moderate to strong westerly shear by the 72 hour forecast period.
Therefore, the cyclone should commence a weakening trend today, and
become a depression by tonight. The official forecast is based
primarily on a blend of the LGEM and decay SHIPS and reflects a
degeneration of the cyclone into a remnant low in 36 hours.

The initial motion is estimated to be west-northwestward, or 295/11
kt, around the southwestern periphery of a subtropical ridge
anchored to the north of the cyclone. Guidance shows that Celia
should turn westward by the 36 hour period as the cyclone decays
into a shallow system and is steered by the low-level trades. The
NHC forecast is weighed heavily on the multi-model consensus, and is
adjusted slightly to the south of the previous forecast beyond day
3.

FORECAST POSITIONS AND MAX WINDS

INIT 14/0900Z 20.3N 135.8W 45 KT 50 MPH
12H 14/1800Z 21.0N 137.4W 35 KT 40 MPH
24H 15/0600Z 21.6N 139.7W 30 KT 35 MPH
36H 15/1800Z 21.9N 142.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 16/0600Z 22.2N 144.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 17/0600Z 22.9N 149.2W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 18/0600Z 23.5N 153.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 19/0600Z 24.5N 158.6W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Roberts

[cycloneye]

TROPICAL STORM CELIA DISCUSSION NUMBER 32
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016
800 AM PDT THU JUL 14 2016

Celia has continued to maintain a small area of deep convection
this morning, however recent microwave imagery shows that the area
of cold cloud tops has become separated from the low-level
center due to some southwesterly shear. Dvorak current intensity
numbers of T3.0 from both TAFB and SAB and the earlier ASCAT data
support keeping an initial wind speed of 45 kt. The remaining
convection should gradually decrease in coverage while Celia
moves over SSTs around 24C during the next day or so. This should
result in weakening, and Celia is forecast to become a
post-tropical cyclone in 24 to 36 hours. After that time, the
cyclone will be moving over slightly warmer SSTs, but moderate
to strong westerly shear should prevent regeneration. A tight
pressure gradient between the post-tropical cyclone and a strong
high pressure area to the north will likely help maintain winds
of around 30 kt with the system for several days.

Recent microwave fixes indicate that Celia is moving west-
northwestward, or 295/10 kt. The cyclone should continue moving
west-northwestward today, but is forecast to turn westward on
Friday as it becomes a shallow system and is steered by the
low-level easterly flow. The NHC forecast track is close to the
GFS, GFS ensemble mean, and the multi-model consensus, which are
all in fairly close agreement.


FORECAST POSITIONS AND MAX WINDS

INIT 14/1500Z 20.8N 136.7W 45 KT 50 MPH
12H 15/0000Z 21.4N 138.4W 35 KT 40 MPH
24H 15/1200Z 21.7N 140.7W 30 KT 35 MPH
36H 16/0000Z 22.0N 143.2W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 16/1200Z 22.3N 145.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 17/1200Z 23.0N 149.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 18/1200Z 23.7N 154.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 19/1200Z 24.5N 160.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown