EPAC: CRISTINA - Post-Tropical

[supercane4867]

Cristina(top image taken today) looks similar to Hurricane Lowell(2014), which had been operationally assessed as a 65kt hurricane with no hesitance

[Yellow Evan]

The Cristina Controversy of 2020 continues.

I'd give it 65kts at least at this point. The eye has seemed to tighten up a bit, which is a good indicator the pressure has probably dropped a few mbs and the gradient has probably tightened a bit too.

It's strange that while in really good conditions Cristina struggled, but when she got farther north with cooling waters and less heat content she started to get her act together.

Slightly off topic, but does anyone know of any research comparing the coupling between ocean and atmosphere in the EPAC compared to other basins around the world? Storms in this basin seem to be able to ride the 26C isotherm and maintain intensity or slightly intensity better than any other basin. They take on an annular-esque structure with larger, more stable eyes and less banding in this basin much more frequently than any other in my opinion.

It's odd but yeah the EPACs storms are considerably more resilient for some reason. Daniel 2006 seemed to have started this all.

I mean in the Atlantic we’ve seen high latitude hurricanes over colder water.

Also these types of storms were an occurrence long before Daniel 06 just not really high profile. They existed in the 80s and 90s too.

[Hammy]

Given how dead the Atlantic is in the MDR, how the Pacific has struggled and almost void of convection the W Pacific has been, I wonder if these are indicators that most things will struggle south of 20N.

[Kingarabian]

The Cristina Controversy of 2020 continues.

I'd give it 65kts at least at this point. The eye has seemed to tighten up a bit, which is a good indicator the pressure has probably dropped a few mbs and the gradient has probably tightened a bit too.

It's strange that while in really good conditions Cristina struggled, but when she got farther north with cooling waters and less heat content she started to get her act together.

Slightly off topic, but does anyone know of any research comparing the coupling between ocean and atmosphere in the EPAC compared to other basins around the world? Storms in this basin seem to be able to ride the 26C isotherm and maintain intensity or slightly intensity better than any other basin. They take on an annular-esque structure with larger, more stable eyes and less banding in this basin much more frequently than any other in my opinion.

It's odd but yeah the EPACs storms are considerably more resilient for some reason. Daniel 2006 seemed to have started this all.

I mean in the Atlantic we’ve seen high latitude hurricanes over colder water.

Also these types of storms were an occurrence long before Daniel 06 just not really high profile. They existed in the 80s and 90s too.

In the past 14 years it seems a lot more prevalent in the EPAC vs anywhere else.

[cycloneye]

Tropical Storm Cristina Discussion Number 19
NWS National Hurricane Center Miami FL EP052020
1100 PM HST Fri Jul 10 2020

Despite being over relatively cool 24 C waters, Cristina is
maintaining its strength for now. Deep convection wraps most of the
way around the center and is strongest on the south side of the
circulation. There remains a large spread in the satellite
intensity estimates that currently range from 45 kt to 65 kt. In
addition, a recent ASCAT-B pass showed maximum winds of 45-50 kt
north of the center. Based on a compromise of all of this data, the
initial intensity is held at 60 kt.

Cristina is moving toward even cooler waters and into a
progressively drier and more stable air mass. These conditions
should cause weakening soon, and the storm is forecast to lose all
of its deep convection and become a post-tropical cyclone in about
60 hours when it will be over SSTs of around 22 C. The NHC
intensity forecast generally follows the IVCN and HCCA consensus
models and calls for steady weakening during the next several days.

Cristina is still moving west-northwestward, and it should continue
moving in that direction for the next couple of days as a mid-level
ridge remains parked over the southwestern United States. Beyond
that time, a westward motion is expected as the weak and shallow
post-tropical cyclone should be steered by the low-level trade
winds. The models remain in good agreement on this scenario, and
the NHC track forecast is largely an update of the previous one.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0900Z 20.4N 118.3W 60 KT 70 MPH
12H 11/1800Z 20.7N 120.3W 55 KT 65 MPH
24H 12/0600Z 21.1N 122.7W 50 KT 60 MPH
36H 12/1800Z 21.5N 125.0W 45 KT 50 MPH
48H 13/0600Z 21.9N 127.3W 40 KT 45 MPH
60H 13/1800Z 22.4N 130.1W 35 KT 40 MPH...POST-TROPICAL
72H 14/0600Z 22.9N 132.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 15/0600Z 23.7N 138.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 16/0600Z 24.0N 142.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

[aspen]

Down to 55 kt for 12z. She will not be operationally assessed as a hurricane.

[cycloneye]

Tropical Storm Cristina Discussion Number 20
NWS National Hurricane Center Miami FL EP052020
500 AM HST Sat Jul 11 2020

Over the past several hours, the coverage of deep convection around
the center of Cristina has gradually decreased as the cyclone
continues to move over relatively cool 24 C waters. The latest
satellite intensity estimates from TAFB, SAB, and the UW-CIMSS
SATCON all support lowering the initial intensity to 55 kt.

Cristina is forecast to move over even cooler waters and into a
progressively drier and more stable air mass over the next couple of
days. These conditions should cause the cyclone to steadily weaken.
By 60 h, Cristina is forecast to have lost its deep convection near
its center and become a remnant low. There is a chance that the
convection could dissipate sooner than indicated, and Cristina could
become a post-tropical cyclone while wind speeds are still greater
than 30 kt. The NHC intensity forecast is largely an update of the
previous one.

Cristina is moving just north of due west at 12 kt. This motion is
expected to continue for the next several days, as the cyclone is
steered by a mid-level ridge centered over the southwestern U.S.
early on, then by the low level easterlies once the system becomes a
remnant low. The NHC forecast lies in the middle of tightly
clustered track guidance, and is little changed from the previous
forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 11/1500Z 20.6N 119.7W 55 KT 65 MPH
12H 12/0000Z 20.9N 121.6W 50 KT 60 MPH
24H 12/1200Z 21.2N 123.9W 45 KT 50 MPH
36H 13/0000Z 21.6N 126.2W 40 KT 45 MPH
48H 13/1200Z 22.1N 128.7W 35 KT 40 MPH
60H 14/0000Z 22.6N 131.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 14/1200Z 23.1N 133.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 15/1200Z 23.8N 139.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 16/1200Z 24.0N 144.0W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Latto

[ScottNAtlanta]

It's odd but yeah the EPACs storms are considerably more resilient for some reason. Daniel 2006 seemed to have started this all.

I mean in the Atlantic we’ve seen high latitude hurricanes over colder water.

Also these types of storms were an occurrence long before Daniel 06 just not really high profile. They existed in the 80s and 90s too.

In the past 14 years it seems a lot more prevalent in the EPAC vs anywhere else.

It actually depends on the temperature gradient as you go up in the atmosphere. If the top end in anomalously cold as compared to the lower levels, you will still develop convection.

[cycloneye]

Tropical Storm Cristina Discussion Number 22
NWS National Hurricane Center Miami FL EP052020
500 PM HST Sat Jul 11 2020

Cristina continues to maintain a broken ring of convection around
its center, and there has been little change in either the
organization or the various satellite intensity estimates since the
last advisory. Based on that, the initial intensity is held at 50
kt.

The initial motion is westward or 270/12. The track forecast
guidance remains in excellent agreement that Cristina should
continue generally westward through the forecast period on the south
side of the subtropical ridge. Only minor adjustments have been
made to the previous forecast track, and the new forecast is in the
middle of the tightly clustered guidance.

The cyclone is over sea surface temperatures near 23C, and the
temperatures cool along the forecast track for the next 60 h or so.
This should cause Cristina to weaken to a depression in about 48 h
and degenerate to a remnant low shortly thereafter. The latest
global models forecast the remnant low to weaken to a trough between
96-120 h, and the NHC forecast thus shows dissipation by 120 h. The
new intensity forecast is otherwise unchanged from the previous
forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0300Z 20.6N 122.2W 50 KT 60 MPH
12H 12/1200Z 20.8N 124.0W 45 KT 50 MPH
24H 13/0000Z 21.2N 126.3W 40 KT 45 MPH
36H 13/1200Z 21.6N 128.7W 35 KT 40 MPH
48H 14/0000Z 22.0N 131.2W 30 KT 35 MPH
60H 14/1200Z 22.4N 133.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 15/0000Z 22.9N 136.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 16/0000Z 23.5N 141.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 17/0000Z...DISSIPATED

$$
Forecaster Beven

[storminabox]

You’re telling me that Barry was a hurricane and Christina never was... smh

[cycloneye]

Tropical Storm Cristina Discussion Number 23
NWS National Hurricane Center Miami FL EP052020
200 AM PDT Sun Jul 12 2020

Conventional satellite and scatterometer data indicate that
Cristina has weakened during the past several hours. Deep
convection has become fragmented near the center of the cyclone,
with only a small amount in the eastern semicircle. A blend of the
satellite estimates from TAFB/SAB gives an initial wind speed of 40
kt for this advisory, and this value is also quite close to a
recent scatterometer pass as well.

Cristina should gradually lose strength during the next few days
due to a combination of very cool waters and increasing shear,
along with nearby dry air. These factors will likely cause the
storm to transition into a non-convective remnant low on Monday.
The intensity forecast is lowered from the previous one, mostly due
to the decreased initial intensity, and the remnant low timing is
earlier as well.

The storm is moving a little north of due west, or 275/11. A
well-defined subtropical ridge over the eastern Pacific should keep
this general motion going for the next several days. The model
guidance has changed little since the last cycle, so no significant
changes were made to the track forecast. None of the global models
hold onto the low-level circulation for long beyond 72 hours, so
dissipation is now shown by day 4.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 20.7N 123.3W 40 KT 45 MPH
12H 12/1800Z 20.9N 125.0W 35 KT 40 MPH
24H 13/0600Z 21.2N 127.4W 30 KT 35 MPH
36H 13/1800Z 21.6N 130.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 14/0600Z 22.1N 132.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 14/1800Z 22.6N 135.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 15/0600Z 23.0N 138.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 16/0600Z...DISSIPATED

$$
Forecaster Blake

[cycloneye]

Tropical Storm Cristina Discussion Number 25
NWS National Hurricane Center Miami FL EP052020
200 PM PDT Sun Jul 12 2020

Cristina has been devoid of deep convection for several hours. The
cyclone's circulation now consists of a large swirl of low- to
mid-level clouds as it continues to move over waters of about 23 C
and into a progressively drier and more stable surrounding
atmosphere. Although intensity estimates continue to steadily
decease, the vortex is taking some additional time to spin down, as
indicated by a recent ASCAT-A overpass that showed maximum winds of
35 kt over a portion of the cyclone. Based on the ASCAT data,
Cristina's intensity is being maintained at 35 kt for this advisory.

Given the environmental conditions, it is unlikely that deep
convection will redevelop near Cristina's center, and the cyclone
is expected to become a remnant low soon. The associated winds will
continue to decrease over the next couple of days and the low is
forecast to open into a trough within a few days. Cristina is
moving westward at 11 kt and this general motion is expected to
continue until dissipation, as the system is steered by the low
level easterlies.


FORECAST POSITIONS AND MAX WINDS

INIT 12/2100Z 20.7N 125.5W 35 KT 40 MPH
12H 13/0600Z 21.0N 127.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 13/1800Z 21.4N 129.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 14/0600Z 22.0N 132.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 14/1800Z 22.5N 135.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 15/0600Z 23.0N 137.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 15/1800Z...DISSIPATED

$$
Forecaster Latto

[aspen]

Someone just put this storm out of its misery.

I can’t believe a system with a track through such an apparently favorable environment with days to intensify couldn’t even hit 65 kt, nor could it surpass the rather low ACE of the Atlantic.

[cycloneye]

Post-Tropical Cyclone Cristina Discussion Number 26
NWS National Hurricane Center Miami FL EP052020
800 PM PDT Sun Jul 12 2020

Cristina has lacked deep convection for more than 12 hours and is
now a swirl of low- to mid-level clouds. The system has therefore
become a remnant low and this is the last NHC advisory. The
estimated intensity is 30 kt, assuming some spin down has occurred
since the last advisory.

Cristina is moving westward near 10 kt, and low-level easterly flow
should steer the remnant low on this general heading for the next
few days. The cyclone is moving over sea surface temperatures of
about 23 deg C that will prevent the redevelopment of organized
convection. Cristina should continue to gradually spin down during
the next 2-3 days until it opens into a trough and dissipates.

FORECAST POSITIONS AND MAX WINDS

INIT 13/0300Z 20.7N 126.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
12H 13/1200Z 21.0N 128.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 14/0000Z 21.5N 130.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 14/1200Z 22.0N 133.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 15/0000Z 22.6N 136.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 15/1200Z 22.9N 139.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 16/0000Z...DISSIPATED

$$
Forecaster Zelinsky