EPAC: CARLOTTA - Post-Tropical

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Re: EPAC: CARLOTTA - Tropical Storm

#61 Postby cycloneye » Sun Jun 17, 2018 9:43 am

Tropical Storm Carlotta Discussion Number 12
NWS National Hurricane Center Miami FL EP042018
1000 AM CDT Sun Jun 17 2018

The system has become quite disorganized this morning and, even with
high-resolution visible satellite images, it is extremely difficult
to locate a center. Dvorak T-numbers from TAFB and SAB continue to
decrease and the intensity estimate is lowered to 35 kt kt for this
advisory. Hopefully, we will receive data from some upcoming ASCAT
scatterometer overpasses in a few hours that will help us better
locate the center of circulation. Carlotta is likely to continue
to spin down due to the interaction with mountainous terrain and
the system should degenerate into a remnant low tomorrow, or sooner.

Given the uncertainty in the location, the initial motion estimate,
305/6 kt, is also highly uncertain. The steering currents around
Carlotta remain weak, but the cyclone is expected to move slowly
northwestward between a couple of mid-level anticyclones. The
official forecast is a little to the left of the previous one but
still north of most of the track guidance for the first 12 to 24
hours of the forecast. Most of the track models lose the analyzed
vortex after that time.

It must again be emphasized that, regardless of the exact track of
Carlotta, the main threat of heavy rainfall and potential of
life-threatening flash floods and mudslides continue over the
southern parts of Guerrero and Michoacan. The rainfall threat will
be enhanced by moist southwesterly flow over the southern Sierra
Madre mountains of Mexico. For details, please see products issued
by your local weather office.

FORECAST POSITIONS AND MAX WINDS

INIT 17/1500Z 17.2N 101.3W 35 KT 40 MPH
12H 18/0000Z 17.7N 102.0W 30 KT 35 MPH
24H 18/1200Z 18.0N 102.4W 25 KT 30 MPH...INLAND
36H 19/0000Z 18.3N 102.8W 20 KT 25 MPH...POST-TROP/INLAND
48H 19/1200Z...DISSIPATED

$$
Forecaster Pasch
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EPAC: CARLOTTA - Tropical Depression

#62 Postby cycloneye » Sun Jun 17, 2018 1:41 pm

BULLETIN
Tropical Depression Carlotta Intermediate Advisory Number 12A
NWS National Hurricane Center Miami FL EP042018
100 PM CDT Sun Jun 17 2018

...CARLOTTA WEAKENS TO A DEPRESSION...


SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...17.2N 101.6W
ABOUT 35 MI...55 KM S OF ZIHUATANEJO MEXICO
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
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Re: EPAC: CARLOTTA - Tropical Depression

#63 Postby cycloneye » Sun Jun 17, 2018 1:43 pm

For a second it was like a hurricane.

@iCyclone
Tropical Storm #CARLOTTA has been meandering along #Mexico coast near #Acapulco this evening. It developed a sexy—but very tiny—inner core earlier, complete with pinhole eye & winds of 55 knots. It's now interacting with land & weakening. But for a half-sec it was kinda hawt.


 https://twitter.com/iCyclone/status/1008223488367210497


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Re: EPAC: CARLOTTA - Tropical Depression

#64 Postby cycloneye » Sun Jun 17, 2018 3:40 pm

Tropical Depression Carlotta Discussion Number 13
NWS National Hurricane Center Miami FL EP042018
400 PM CDT Sun Jun 17 2018

Data from a recent scatterometer pass indicated Carlotta still had
a small circulation, but that it was quite weak with maximum winds
near 25 kt. Persistent northerly shear continues to affect the
depression. The system has lacked much organized deep convection
for the past several hours and it is likely to degenerate into a
remnant low overnight. Accordingly, the official forecast shows the
system becoming post-tropical by early Monday.

Based on the ASCAT observations, the center has been re-positioned a
little to the southeast of the previous track. The initial motion
estimate is now 300/6 kt. High pressure to the north of Carlotta
should maintain a general west-northwestward track for the next day
or two.

The main threat from Carlotta continues to be heavy rains over the
southern portions of the states of Guerrero, Michoacan, and Colima.
These rains, which will likely be enhanced by moist upslope flow
over the southern Sierra Madre mountains of Mexico, could produce
life-threatening flash floods and mudslides. Consult products
issued by your national meteorological service.

FORECAST POSITIONS AND MAX WINDS

INIT 17/2100Z 17.1N 101.9W 25 KT 30 MPH
12H 18/0600Z 17.5N 102.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 18/1800Z...DISSIPATED

$$
Forecaster Pasch
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Re: EPAC: CARLOTTA - Tropical Depression

#65 Postby cycloneye » Sun Jun 17, 2018 9:50 pm

Tropical Depression Carlotta Discussion Number 14
NWS National Hurricane Center Miami FL EP042018
1000 PM CDT Sun Jun 17 2018

Visible satellite imagery indicates that Carlotta has maintained a
small but robust low-level circulation, with strong convection
bursting over and south of the well-defined center. Satellite
intensity estimates are T2.0/30 kt from TAFB and T2.3/33 kt from
UW-CIMSS ADT. Based on these data, the intensity is being
maintained at 25 kt and Carlotta is still classified as a tropical
cyclone.

The initial motion estimate is a slightly slower 295/04 kt. The
recent development of deep convection has likely amplified the
vertical circulation, resulting in the forward motion being
slightly retarded by the north-northwesterly upper-level winds.
However, a stout ridge to the north of the small cyclone should keep
the system moving in a general west-northwestward direction just
offshore the coast of Mexico for the next day or so.

Pulsing convection with tops to near -80C has been occurring since
the previous advisory. However, vertical wind shear of around 15 kt
along with drier mid-level air coming in off of mainland Mexico are
expected to steadily weaken the system, resulting in degeneration
into a remnant low on Monday.

The main threat from Carlotta continues to be heavy rains over the
southern portions of the states of Guerrero, Michoacan, and Colima.
These rains, which will likely be enhanced by moist upslope flow
over the southern Sierra Madre mountains of Mexico, could produce
life-threatening flash floods and mudslides. Consult products
issued by your national meteorological service.


FORECAST POSITIONS AND MAX WINDS

INIT 18/0300Z 17.2N 102.2W 25 KT 30 MPH
12H 18/1200Z 17.4N 102.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 19/0000Z...DISSIPATED

$$
Forecaster Stewart
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Re: EPAC: CARLOTTA - Tropical Depression

#66 Postby HurricaneRyan » Sun Jun 17, 2018 10:23 pm

Did Carlotta even make landfall?
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Re: EPAC: CARLOTTA - Tropical Depression

#67 Postby cycloneye » Mon Jun 18, 2018 5:05 am

Tropical Depression Carlotta Discussion Number 15
NWS National Hurricane Center Miami FL EP042018
400 AM CDT Mon Jun 18 2018

Successive bursts of deep convection have been occurring since last
evening, each one to the northwest of the previous one, which
likely indicates that Carlotta still has a tight circulation and
well-defined center. As such, the cyclone has not yet dissipated
nor degenerated into a remnant low. Satellite classifications
support maintaining a 25-kt initial intensity.

Based on the propagation of convection, Carlotta's center appears
to be nearing the coast of Mexico, and the initial motion is
northwestward, or 305/4 kt. The depression is entering an area of
low-level southerly to westerly winds, which should force its small
circulation closer to land. Due to steep coastal mountains,
however, the low-level center is unlikely to move inland and should
dissipate near the coast. A 12-hour forecast point based on
persistence is provided, but Carlotta could dissipate at any time.

Each time a pulse of deep convection occurs, it is displaced south
of the center due to 10-15 kt of north-northeasterly shear. The
shear is not expected to decrease in the short term, which could
allow Carlotta to continue as a tropical depression until the
circulation is disrupted by the terrain of Mexico and dissipates.

Heavy rains could still produce life-threatening flash floods and
mudslides over southern portions of the states of Guerrero,
Michoacan, and Colima. Consult products issued by the Mexican
meteorological service for more information.

FORECAST POSITIONS AND MAX WINDS

INIT 18/0900Z 17.7N 102.6W 25 KT 30 MPH
12H 18/1800Z 18.1N 103.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 19/0600Z...DISSIPATED

$$
Forecaster Berg
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Re: EPAC: CARLOTTA - Tropical Depression

#68 Postby cycloneye » Mon Jun 18, 2018 9:41 am

Tropical Depression Carlotta Discussion Number 16
NWS National Hurricane Center Miami FL EP042018
1000 AM CDT Mon Jun 18 2018

Locating Carlotta's center this morning in conventional satellite
imagery has been difficult. An earlier 0806 UTC GMI polar orbital
microwave pass, however, was helpful in confirming that the system
has in fact persisted as a small, relatively symmetric tropical
cyclone. A blend of subjective and objective T-numbers supports 25
kt for this advisory.

With the assistance of the aforementioned microwave image, the
initial motion is estimated to be 310/4 kt, within the weak low-
to mid-level flow generated by high pressure to the north.
Landfall still appears to be unlikely due to the expected motion
parallel to the coastline, but only a slight northward deviation
could bring the center of the small cyclone onshore. In any
event, dissipation should occur just offshore by Tuesday morning, if
not sooner.

Heavy rains could still produce life-threatening flash floods and
mudslides over southern portions of the states of Guerrero,
Michoacan, and Colima. Consult products issued by the Mexican
meteorological service for more information.


FORECAST POSITIONS AND MAX WINDS

INIT 18/1500Z 17.9N 103.1W 25 KT 30 MPH
12H 19/0000Z 18.1N 103.2W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 19/1200Z...DISSIPATED

$$
Forecaster Roberts
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Re: EPAC: CARLOTTA - Tropical Depression

#69 Postby cycloneye » Mon Jun 18, 2018 3:36 pm

Tropical Depression Carlotta Discussion Number 17
NWS National Hurricane Center Miami FL EP042018
400 PM CDT Mon Jun 18 2018

The center of the depression, if it exists, remains very difficult
to locate either with geostationary or microwave satellite
imagery. In fact, the microwave images suggest that there is no
longer a center. Unfortunately, the scatterometer swath missed the
estimated location of Carlotta so that was of no help. Given these
uncertainties, we will write at least one more advisory on this
system, but the next one could be the last. The current intensity
is held at 25 kt based on continuity and a Dvorak estimate from
SAB. It is anticipated that the small system will dissipate by
early tomorrow due to interaction with land.

The initial motion is a highly uncertain 315/4 kt. There is little
in the way of track guidance available, since most of the models are
unable to analyze a center for the tropical cyclone. Carlotta or
its remnant should continue to move northwestward to
north-northwestward, in a weakness of the subtropical ridge, until
dissipation.

Heavy rains could still produce life-threatening flash floods and
mudslides over southern portions of the states of Guerrero,
Michoacan, and Colima. Consult products issued by the Mexican
meteorological service for more information.


FORECAST POSITIONS AND MAX WINDS

INIT 18/2100Z 18.1N 103.3W 25 KT 30 MPH
12H 19/0600Z 18.5N 103.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 19/1800Z...DISSIPATED

$$
Forecaster Pasch
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Re: EPAC: CARLOTTA - Post-Tropical

#70 Postby cycloneye » Mon Jun 18, 2018 9:36 pm

Bye.

Post-Tropical Cyclone Carlotta Discussion Number 18
NWS National Hurricane Center Miami FL EP042018
1000 PM CDT Mon Jun 18 2018

A 2239Z SSMI/S microwave image indicated that a small mid-level
circulation remained, but Carlotta's low-level circulation was
either very small and indistinct, or it was located along the coast
of Mexico. For this, the final advisory, it is assumed that the
low-level center is beneath the remnant mid-level circulation. The
upper-level circulation noted in hi-res GOES-16 visible imagery has
continued to move southwestward and decouple from the rest of the
circulation, and what little convection that does exist is rather
amorphous-looking and disorganized. Based on the disheveled
appearance of the system, Carlotta is considered to be a remnant low
pressure system with 20-kt winds.

The initial motion estimate is 315/03 kt. Steering currents are
weak and the shallow nature of the tiny cyclone should prevent
Carlotta's remnant circulation from moving inland over the high
mountainous terrain of southwestern Mexico. As a result, the system
is forecast to drift northwestward and skirt the coast of Mexico
for the next 12-24 hours until dissipation or absorption into the
monsoon trough occurs some time on Tuesday.

Although there could be some intermittent short-lived bursts of
convection, proximity to land, modest northerly vertical wind
shear, and dry mid-level air should prevent the remnant low from
regenerating into a tropical cyclone.

Although Carlotta is no longer a tropical cyclone, an abundance of
tropical moisture flowing inland from the Pacific is expected to
produce heavy rains, along with life-threatening flash floods and
mudslides over southern portions of the states of Guerrero,
Michoacan, and Colima for the next couple of days. Consult products
issued by the Mexican meteorological service for more information.

This is the last advisory on Carlotta issued by the National
Hurricane Center. For additional information on the remnant low...
please see High Seas Forecasts issued by the National Weather
Service...under AWIPS header NFDHSFEPI and WMO header FZPN02 KWBC.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0300Z 18.2N 103.6W 20 KT 25 MPH...POST-TROPICAL
12H 19/1200Z 18.4N 104.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 20/0000Z...DISSIPATED

$$
Forecaster Stewart
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