EPAC: BARBARA - Remnants

[cycloneye]

Hurricane Barbara Discussion Number 13
NWS National Hurricane Center Miami FL EP022019
500 AM HST Wed Jul 03 2019

It appears that the weakening process has already begun. The ring
of intense convection surrounding the eye has warmed up and
consequently, Dvorak numbers have continued to fall. Based on an
average of the latest objective and subjective numbers, the initial
intensity has been adjusted down to 125 kt in this advisory.
Barbara's circulation is beginning to move toward cooler waters so a
gradual weakening trend should prevail, although some minor
fluctuations in intensity are possible today. Faster weakening
is anticipated once the shear increases significantly in about 2
days. In fact, Barbara could lose its deep convection, and thus
become post tropical, around the time it is forecast to cross 140W
into the central Pacific basin. This is indicated by most of the
intensity guidance.

Barbara is moving toward the west-northwest or 295 degrees at 9
kt. The hurricane has reached the southwestern edge of the
subtropical high that has been steering the cyclone, and this flow
pattern should force Barbara to move slowly toward the northwest
during the next 2 days or so. After that time, a new ridge is
forecast to re-build north of the cyclone, resulting in a more
westerly track. In addition, since Barbara is forecast to become a
weak shallow cyclone, it will likely become steered by the low-level
trade winds. The NHC forecast is not different from the previous
one, and it continues to be in the middle of the guidance envelope
and basically on top of the multi-model consensus TVCE.


FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 13.9N 126.6W 125 KT 145 MPH
12H 04/0000Z 14.6N 128.0W 115 KT 130 MPH
24H 04/1200Z 15.7N 129.7W 105 KT 120 MPH
36H 05/0000Z 16.9N 131.5W 95 KT 110 MPH
48H 05/1200Z 18.0N 133.2W 80 KT 90 MPH
72H 06/1200Z 19.0N 138.0W 40 KT 45 MPH
96H 07/1200Z 19.0N 144.0W 35 KT 40 MPH...POST-TROPICAL
120H 08/1200Z 18.5N 150.0W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Avila

[HurricaneEnzo]

I feel like this was probably minimal Cat 5 at some point in it's life. Unfortunately we have to deal with this a lot with these Pacific storms that are out 'in the middle of nowhere'. Maybe one day technology for unmanned flights will be more advanced and affordable so we can get recon in these storms.

[storm_in_a_teacup]

https://twitter.com/TropicalTidbits/status/1146387963917606912

I take it the 3rd bullet point refers to the broad ring of red that appears inside the ring of black?

(Also I am not feeling at my best today. Perhaps I too am about to undergo an eyewall replacement cycle (sorry)
)

[AnnularCane]

https://twitter.com/TropicalTidbits/status/1146387963917606912

I take it the 3rd bullet point refers to the broad ring of red that appears inside the ring of black?

(Also I am not feeling at my best today. Perhaps I too am about to undergo an eyewall replacement cycle (sorry)
)

As long as it's not an acute case of wind shear. That would be bad. (Also sorry. Hope you feel better.)

[cycloneye]

Hurricane Barbara Discussion Number 14
NWS National Hurricane Center Miami FL EP022019
1100 AM HST Wed Jul 03 2019

Satellite images indicate that Barbara has continued to gradually
weaken. The eye is not as distinct as it has been during the past 24
hours, and the cloud tops surrounding the eye have warmed. Dvorak
numbers have continued to fall, and based on an average of the
latest objective and subjective numbers, the initial intensity has
been adjusted down to 120 kt in this advisory. Barbara's circulation
is beginning to move toward cooler waters so a gradual weakening
trend should prevail. Faster weakening is anticipated once the shear
increases significantly in about 2 days. In fact, Barbara could lose
its deep convection, and thus become post-tropical, around the time
it is forecast to cross 140W into the central Pacific basin. This
is indicated by most of the intensity guidance.

Barbara is moving toward the west-northwest or 300 degrees at 10 kt.
The hurricane has reached the southwestern edge of the subtropical
ridge, and this flow pattern should steer Barbara on a northwest
track during the next 2 days or so. After that time, a new ridge is
forecast to build north of the cyclone, resulting in a turn back
toward the west. In addition, since Barbara is forecast to become a
weak and shallow cyclone, it will likely become steered westward by
the low-level trade winds by Saturday. The NHC forecast is not
different from the previous one, and it continues to be in the
middle of the guidance envelope and very close to the multi-model
consensus TVCE.


FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 14.3N 127.5W 120 KT 140 MPH
12H 04/0600Z 15.1N 128.9W 110 KT 125 MPH
24H 04/1800Z 16.3N 130.4W 100 KT 115 MPH
36H 05/0600Z 17.5N 132.0W 80 KT 90 MPH
48H 05/1800Z 18.5N 134.0W 60 KT 70 MPH
72H 06/1800Z 19.0N 139.0W 35 KT 40 MPH
96H 07/1800Z 19.0N 145.0W 30 KT 35 MPH...POST-TROPICAL
120H 08/1800Z 18.5N 151.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Avila

[cycloneye]

Still has some punch left.

Location: 14.6°N 128.0°W
Maximum Winds: 115 kt Gusts: N/A
Minimum Central Pressure: 947 mb
Environmental Pressure: 1009 mb
Radius of Circulation: 210 NM
Radius of Maximum Wind: 10 NM

[cycloneye]

 https://twitter.com/DrRickKnabb/status/1146596389616586752

[cycloneye]

Hurricane Barbara Discussion Number 15
NWS National Hurricane Center Miami FL EP022019
500 PM HST Wed Jul 03 2019

Cloud tops around the still well-defined eye of Barbara have warmed
a little more this afternoon/evening, suggesting that the hurricane
continues to weaken. Recent satellite-based intensity estimates
range from 102 to 127 kt, and the initial intensity of Barbara has
been lowered to 115 kt, in the middle of the various fixes.

Virtually no change has been made to the intensity forecast. Barbara
will be moving over cooler SSTs for the next several days, and the
hurricane should cross the 26 degree C isotherm in about 24 hours.
The vertical wind shear is also forecast to increase sharply in
about 36 to 48 hours, which should hasten the weakening of the
tropical cyclone. These factors, along with a drier surrounding
environment, will likely cause Barbara to lose its deep convection
and become post-tropical in about 3 days, possibly just after
reaching the central Pacific basin. The intensity guidance is in
extremely good agreement on this general scenario, with the only
uncertainty being the exact rate at which Barbara will weaken, and
the NHC forecast is near the middle of the intensity guidance.

Barbara continues to move steadily west-northwestward or 300/10 kt.
The new NHC forecast is practically on top of the previous one, and
there have been no changes of significance in the track forecast
guidance. The hurricane is currently moving along the southwestern
edge of a mid-level subtropical ridge that extends from Mexico over
much of the eastern North Pacific, and this should continue for
another day or two. As it weakens, Barbara will be increasingly
steered by low-level easterly trade wind flow, and this should
causes the cyclone to turn toward the west by the weekend. The NHC
forecast continues to lie near the middle of the guidance envelope
and very near TVCN and HCCA.

FORECAST POSITIONS AND MAX WINDS

INIT 04/0300Z 14.9N 128.5W 115 KT 130 MPH
12H 04/1200Z 15.8N 129.7W 105 KT 120 MPH
24H 05/0000Z 17.0N 131.3W 90 KT 105 MPH
36H 05/1200Z 18.2N 133.1W 75 KT 85 MPH
48H 06/0000Z 19.0N 135.1W 55 KT 65 MPH
72H 07/0000Z 19.1N 140.6W 35 KT 40 MPH
96H 08/0000Z 18.8N 146.9W 30 KT 35 MPH...POST-TROPICAL
120H 09/0000Z 18.5N 153.0W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Zelinsky

[cycloneye]

Hurricane Barbara Discussion Number 16
NWS National Hurricane Center Miami FL EP022019
1100 PM HST Wed Jul 03 2019

Barbara is on a weakening trend. Although the hurricane is still
impressive in satellite images with a well-defined eye and
relatively symmetric convective pattern, the cloud tops have been
gradually warming in the eyewall. Accordingly, the subjective and
objective satellite intensity estimates have been falling, and the
initial intensity is lowered to 105 kt. This intensity estimate is
in best agreement with the Dvorak CI-numbers from TAFB and SAB.

The hurricane is still in relatively favorable conditions of
marginally warm waters, low wind shear, and a fairly moist
environment. However, these conditions are expected to change
significantly during the next couple of days. Barbara is forecast
to cross the 26 degree C isotherm in about 12 hours, and it will
also be moving into a progressively drier airmass during the next
day or two. These conditions combined with a notable increase in
southwesterly shear suggest that rapid weakening is likely. Barbara
is forecast to weaken to a tropical storm by 36 hours and
degenerate to a post-tropical cyclone by day 3. The post-tropical
transition will likely occur around the time the cyclone enters the
Central Pacific basin, when Barbara is forecast to be over 25 degree
C waters and in an environment of about 30 kt of southwesterly
shear. The NHC intensity forecast lies near the various intensity
consensus models.

Barbara is moving west-northwestward at 10 kt steered by a mid-level
ridge to its northeast. The hurricane is forecast to make a slight
turn to the northwest soon, and it should continue in that general
direction during the next day or so while it moves along the
southwestern periphery of the ridge. After that time, low- to
mid-level ridging is expected to build to the north of the
weakening cyclone and that should cause it to move westward at a
faster pace. The remnants of Barbara are expected to approach the
Hawaiian Islands in about 5 days. The track models are tightly
clustered, and only small changes were made to the previous NHC
track forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 04/0900Z 15.4N 129.2W 105 KT 120 MPH
12H 04/1800Z 16.3N 130.4W 95 KT 110 MPH
24H 05/0600Z 17.6N 132.1W 75 KT 85 MPH
36H 05/1800Z 18.6N 134.0W 60 KT 70 MPH
48H 06/0600Z 19.1N 136.3W 45 KT 50 MPH
72H 07/0600Z 19.1N 142.1W 35 KT 40 MPH...POST-TROPICAL
96H 08/0600Z 18.7N 148.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 09/0600Z 18.5N 155.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

[cycloneye]

Hurricane Barbara Discussion Number 17
NWS National Hurricane Center Miami FL EP022019
500 AM HST Thu Jul 04 2019

Satellite images indicate that Barbara continues to gradually
weaken. Convection in the eyewall is becoming less intense, with
eye temperatures slowly falling. A consensus of the latest
satellite estimates suggests 100 kt as the initial wind speed.
The hurricane is entering an environment that will likely promote
rapid weakening during the next couple of days. Barbara is forecast
to traverse sub-26C waters and encounter increasing southwesterly
shear, which would help to mix in drier air from the mid-levels of
the atmosphere. Thus, the cyclone should weaken to a tropical storm
by 36 hours and degenerate into a post-tropical cyclone around
the time it enters the Central Pacific basin. The new NHC
prediction is similar to the previous one and is a bit lower than
the model consensus.

Barbara has turned northwestward recently, and is moving about
310/10 kt. This general path is forecast until tomorrow when a
mid-level ridge builds to north of the cyclone, causing a
west-northwestward motion. As Barbara weakens, it should
turn westward on Saturday, steered by the low-level flow. Model
guidance is in very good agreement on this scenario, and no
significant changes were required to the previous forecast. All of
the model dissipate the cyclone east of the Hawaiian Islands,
although the remnants could move across that area in about 5 days.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 16.0N 130.0W 100 KT 115 MPH
12H 05/0000Z 17.0N 131.2W 85 KT 100 MPH
24H 05/1200Z 18.1N 133.0W 70 KT 80 MPH
36H 06/0000Z 18.9N 135.2W 50 KT 60 MPH
48H 06/1200Z 19.2N 137.8W 40 KT 45 MPH
72H 07/1200Z 19.0N 143.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 08/1200Z 18.8N 150.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 09/1200Z...DISSIPATED

$$
Forecaster Blake

[Kingarabian]

Let's see how long it lasts:

[cycloneye]

Hurricane Barbara Discussion Number 18
NWS National Hurricane Center Miami FL EP022019
1100 AM HST Thu Jul 04 2019

The eye of Barbara has gradually been filling in during the day,
with eyewall convection eroding somewhat on the south side. In
addition, the cloud pattern has become elongated to the north -- a
sign that southwesterly shear is affecting the circulation. A blend
of the satellite intensity estimates, with more weight on the
subjective estimates, gives 85 kt as the initial wind speed. Barbara
should rapidly weaken over the next day or so due to cool waters,
increasing southwesterly shear, and dry air entrainment. The cyclone
is forecast to weaken into a tropical storm by 24 hours and
degenerate into a post-tropical cyclone near or just before it
enters the Central Pacific basin. The new NHC prediction is similar
to the previous one, close to the model consensus.

Barbara continues moving northwestward, or 310/10 kt. This general
path is forecast until tomorrow when a mid-level ridge builds to
north of the cyclone, causing a slightly faster west-northwestward
motion. As Barbara weakens, it should turn westward and accelerate
on Saturday, steered by the low-level flow. The overall model
guidance envelope is virtually unchanged from the previous one, and
no significant changes were made to the forecast. All of the models
dissipate the cyclone east of the Hawaiian Islands, although the
remnants could move across that area in 4-5 days.

FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 16.7N 130.8W 85 KT 100 MPH
12H 05/0600Z 17.6N 132.1W 70 KT 80 MPH
24H 05/1800Z 18.6N 134.1W 55 KT 65 MPH
36H 06/0600Z 19.1N 136.6W 45 KT 50 MPH
48H 06/1800Z 19.2N 139.3W 35 KT 40 MPH...POST-TROPICAL
72H 07/1800Z 18.9N 145.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 08/1800Z 18.9N 152.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 09/1800Z...DISSIPATED

$$
Forecaster Blake

[Ntxw]

17 units Barbara has added to the EPAC. With the NHC forecast a little over 2 units more before post so she may end up being a ~20 unit system.

[cycloneye]

Hurricane Barbara Discussion Number 19
NWS National Hurricane Center Miami FL EP022019
500 PM HST Thu Jul 04 2019

Barbara still appears to be a hurricane on the downswing. The
cyclone had a surprising last gasp earlier this afternoon with a
ring of cold cloud-tops surrounding the well-defined eye in infrared
imagery, and satellite intensity estimates actually increased
slightly since the last advisory. However, several microwave passes
during the past 6 hours revealed that all of the active deep
convection is limited to the northern semicircle of the hurricane,
likely due to the continued effects of southwesterly shear.
Furthermore, the eye of the hurricane has become poorly defined
since around 0000 UTC. Although the intensity of Barbara is 85 kt
for this advisory, rapid weakening should resume imminently due to
the aforementioned shear, cold waters, and a relatively dry
surrounding environment. No changes of significance were made to the
NHC intensity forecast, which remains close to the intensity
consensus, IVCN, and Barbara is still forecast to become a remnant
low on Saturday.

No changes of note were made to the track forecast either. Barbara's
estimated motion is 310/10 kt, but a turn toward the west-northwest
is anticipated on Friday. The cyclone should then turn westward as
it weakens, steered by low-level easterlies, and will likely remain
on that general heading until it dissipates east of the Hawaiian
Islands early next week. The track guidance is in good agreement and
the NHC forecast closely follows the simple track consensus TVCN.

FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 17.3N 131.7W 85 KT 100 MPH
12H 05/1200Z 18.1N 133.1W 70 KT 80 MPH
24H 06/0000Z 18.8N 135.4W 55 KT 65 MPH
36H 06/1200Z 19.1N 138.0W 40 KT 45 MPH
48H 07/0000Z 19.2N 141.1W 35 KT 40 MPH...POST-TROPICAL
72H 08/0000Z 18.7N 147.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 09/0000Z...DISSIPATED

$$
Forecaster Zelinsky

[HurricaneRyan]

It was good while it lasted

[cycloneye]

Hurricane Barbara Discussion Number 20
NWS National Hurricane Center Miami FL EP022019
1100 PM HST Thu Jul 04 2019

Conventional and microwave satellite imagery indicates that Barbara
is shearing apart, with the eyewall structure disintegrating and
the low-level center located to the south of the remaining deep
convection. Recent scatterometer overpasses showed several 65-kt
wind vectors near the center, and based on a blend of these data
and other satellite intensity estimates the initial intensity is
reduced to 70 kt. Increasing southwesterly shear, dry air
entrainment, and cool sea surface temperatures along the forecast
track should cause continued rapid weakening, and Barbara is
forecast to decay to a remnant low late Saturday or Saturday night
and weaken to a trough by Monday.

The initial motion is now 305/10. The cyclone should turn
west-northwestward later today and westward by Saturday as easterly
flow on the south side of a large low- to mid-level ridge becomes
the predominant steering mechanism. There has been little change
in the track guidance since the last advisory. Thus, the new
forecast track is similar to the previous track and lies near the
various consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 17.7N 132.6W 70 KT 80 MPH
12H 05/1800Z 18.4N 134.2W 60 KT 70 MPH
24H 06/0600Z 18.9N 136.8W 45 KT 50 MPH
36H 06/1800Z 19.0N 139.6W 35 KT 40 MPH
48H 07/0600Z 18.9N 142.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 08/0600Z 18.5N 150.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 09/0600Z...DISSIPATED

$$
Forecaster Beven

[cycloneye]

Tropical Storm Barbara Discussion Number 21
NWS National Hurricane Center Miami FL EP022019
500 AM HST Fri Jul 05 2019

Strong southwesterly shear and marginal SSTs are causing Barbara to
continue to weaken. The associated deep convection, which is
displaced to the northeast of the cyclone center, is diminishing in
both coverage and intensity. Using a blend of Dvorak Current
Intensity and T-numbers from TAFB and SAB results in an advisory
intensity estimate of 60 kt. Since the shear is expected to
increase further, continued weakening is likely and Barbara should
degenerate into a remnant low in 48 hours or sooner. The official
intensity forecast is near or above the latest model consensus.

The initial motion estimate is 305/11 kt. A low- to mid-level
ridge is forecast to build to the north of Barbara over the next
couple of days. As a result, the cyclone should turn toward the
west-northwest and west during the next 24 to 48 hours. The
official track forecast is similar to the previous one, and very
close to the simple and corrected model consensus tracks.

FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 18.4N 133.6W 60 KT 70 MPH
12H 06/0000Z 18.8N 135.4W 50 KT 60 MPH
24H 06/1200Z 19.2N 138.1W 40 KT 45 MPH
36H 07/0000Z 19.3N 141.0W 30 KT 35 MPH
48H 07/1200Z 19.1N 144.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 08/1200Z 19.0N 151.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 09/1200Z...DISSIPATED

$$
Forecaster Pasch

[Kingarabian]

Strongest "B" storm since 1971.

[cycloneye]

Tropical Storm Barbara Discussion Number 22
NWS National Hurricane Center Miami FL EP022019
1100 AM HST Fri Jul 05 2019

Increasingly strong vertical shear has stripped away the deep
convection from the system. A recent ASCAT overpass indicates that
the cyclone's intensity is around 50 kt. Although Barbara will not
be moving over much cooler waters during the next couple of days,
the shear is forecast to increase to more than 30 kt with an
accompanying decrease in mid-level moisture. These hostile
environmental factors will likely cause continued weakening, and the
system should degenerate into a post-tropical cyclone by tomorrow.
The NHC intensity forecast is close to the latest corrected model
consensus, HCCA.

Barbara is turning toward the left and the initial motion estimate
is now west-northwestward, or 290/11 kt. There is basically no
change to the track forecast reasoning. A low- to mid-level ridge
to the north of the cyclone should induce a turn toward the west
with some acceleration. The official track forecast is, again, very
similar to the dynamical model consensus solution.

FORECAST POSITIONS AND MAX WINDS

INIT 05/2100Z 18.6N 134.7W 50 KT 60 MPH
12H 06/0600Z 18.9N 136.8W 35 KT 40 MPH...POST-TROPICAL
24H 06/1800Z 19.0N 139.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 07/0600Z 18.8N 142.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 07/1800Z 18.8N 146.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 08/1800Z...DISSIPATED

$$
Forecaster Pasch

[cycloneye]

Very fast demise.

Tropical Storm Barbara Discussion Number 23
NWS National Hurricane Center Miami FL EP022019
500 PM HST Fri Jul 05 2019

Barbara is fading fast. The cyclone has been devoid of deep
convection since this morning and unless it has an unexpected
resurgence of thunderstorm activity during the next few hours, it
will likely be declared post-tropical later tonight. Barbara's
intensity is set at 45 kt, assuming that the winds have decreased a
little in 6 hours since a pair of ASCAT passes showed 45-50 kt peak
winds. High shear, low mid-level moisture, and cool SSTs should
prevent Barbara from recovering during the next couple of days, so a
steady spin down is forecast. This should cause the system to open
into a trough within the next three days, if not sooner.

Barbara is now moving westward, with an initial motion of 275/12
kt. A low-level ridge to the north of the cyclone will keep it
moving generally westward with a slight increase in speed for the
next few days until Barbara dissipates. No major changes were made
to the NHC track forecast, which is based primarily on a blend of
the GFS and ECMWF models.

FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 18.6N 136.2W 45 KT 50 MPH
12H 06/1200Z 18.7N 138.3W 35 KT 40 MPH...POST-TROPICAL
24H 07/0000Z 18.6N 141.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 07/1200Z 18.6N 144.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 08/0000Z 18.4N 148.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 09/0000Z...DISSIPATED

$$
Forecaster Zelinsky