ATL: RINA - Advisories

[cycloneye]

Tropical Storm Rina Discussion Number 1
NWS National Hurricane Center Miami FL AL182023
1100 AM AST Thu Sep 28 2023

Visible imagery early this morning indicates that a well-defined
center has emerged to the northwest of persistent deep convective
activity. A recent ASCAT pass and subjective Dvorak estimates from
TAFB both indicate that the system has become a tropical cyclone.
Thus, advisories have been initiated on Tropical Storm Rina.

The recent partial ASCAT pass indicated winds in the 30-35 kt
range but did not capture the most intense convection east of the
center. Therefore, the current intensity for this advisory is set
at 35 kt. Moderate deep-layer westerly shear is likely to limit
intensification in the short term, and this shear is expected to
increase this weekend and early next week. Persistent shear, in
addition to the close proximity and uncertain interaction with
Tropical Storm Philippe, should limit intensification during the
forecast period. The NHC forecast is in the middle of the guidance
envelope and very close to the HCCA solution. Rina is expected to
remain a tropical storm throughout the forecast period, though some
of the regional hurricane models do indicate a faster rate of
intensification during the next several days compared to the NHC
forecast.

Rina is moving north-northwestward, with an initial forward speed
near 9 kt. The tropical storm should begin to turn more westward
today and continue this general motion for the next several days.
Early next week, the system is expected to turn northward as a
mid-level ridge builds to the west. The NHC forecast is a blend of
the HCCA and TVCN consensus guidance throughout the forecast
period. Confidence in the track forecast is lower than normal based
on the model spread and uncertainty regarding the potential
interaction with Tropical Storm Philippe during the next several
days.

FORECAST POSITIONS AND MAX WINDS

INIT 28/1500Z 17.4N 45.0W 35 KT 40 MPH
12H 29/0000Z 18.5N 45.8W 35 KT 40 MPH
24H 29/1200Z 19.2N 46.8W 40 KT 45 MPH
36H 30/0000Z 19.6N 47.8W 45 KT 50 MPH
48H 30/1200Z 19.9N 49.0W 50 KT 60 MPH
60H 01/0000Z 20.4N 50.4W 50 KT 60 MPH
72H 01/1200Z 21.1N 52.2W 45 KT 50 MPH
96H 02/1200Z 23.9N 56.2W 40 KT 45 MPH
120H 03/1200Z 26.2N 58.2W 40 KT 45 MPH

$$
Forecaster Hogsett/Cangialosi

[cycloneye]

Tropical Storm Rina Discussion Number 2
NWS National Hurricane Center Miami FL AL182023
500 PM AST Thu Sep 28 2023

Tropical Storm Rina has not changed much this afternoon. Visible
satellite imagery indicates that the center of circulation is
mostly exposed to the northwest of persistent deep convective
activity. Subjective Dvorak estimates from SAB and TAFB both support
an initial intensity of 35 kt for this advisory.

A combination of Rina's close proximity to Tropical Storm Philippe
and moderate deep-layer northwesterly shear is likely to limit
intensification in the short term. This shear is expected to
increase this weekend and early next week, and it not forecast to
abate during the forecast period. The NHC forecast remains in the
middle of the guidance envelope and is slightly lower than the prior
forecast. While Rina is expected to remain a tropical storm
throughout the forecast period, uncertainty in the intensity
forecast is higher than normal due to the potential interaction with
Philippe.

Rina is moving northwestward, with an initial forward speed
near 12 kt. The tropical storm should begin to turn more westward
tonight and continue this general motion for the next several days.
Early next week, the system is expected to turn northward and
eventually northeastward as a mid-level ridge builds to the west.
The NHC forecast is a blend of the prior forecast and the HCCA and
TVCN consensus guidance throughout the forecast period. As
with the intensity forecast, confidence in the track forecast is
lower than normal due to uncertainty regarding the potential
interaction of Rina with Tropical Storm Philippe during the next
several days.


FORECAST POSITIONS AND MAX WINDS

INIT 28/2100Z 18.1N 46.2W 35 KT 40 MPH
12H 29/0600Z 18.8N 46.9W 40 KT 45 MPH
24H 29/1800Z 19.4N 47.9W 45 KT 50 MPH
36H 30/0600Z 19.7N 48.9W 45 KT 50 MPH
48H 30/1800Z 20.1N 50.1W 45 KT 50 MPH
60H 01/0600Z 20.6N 51.4W 45 KT 50 MPH
72H 01/1800Z 21.5N 53.3W 40 KT 45 MPH
96H 02/1800Z 24.2N 56.7W 35 KT 40 MPH
120H 03/1800Z 26.8N 58.4W 35 KT 40 MPH

$$
Forecaster Hogsett/Cangialosi

[cycloneye]

Tropical Storm Rina Discussion Number 3
NWS National Hurricane Center Miami FL AL182023
1100 PM AST Thu Sep 28 2023

The future for Rina has not become any clearer during the past
several hours. The cyclone is more or less unchanged since the last
advisory, with its center still generally exposed to the northwest
of the associated deep convection. The intensity remains 35 kt based
on recent operational SAB, TAFB, and UW-CIMSS ADT estimates.

During the past day or so, the guidance has flip-flopped over
whether Rina or nearby Tropical Storm Philippe will become dominant.
While Rina appears to be the better organized of the two at the
moment, the latest runs of most models indicate that Philippe is
more likely to become the dominant cyclone by early next week. Until
the forecast becomes more consistent, it appears prudent to make
only very small incremental changes to the official NHC forecast.
Therefore, both the intensity and track forecasts are very similar
to the previous advisory, but confidence in the NHC forecast is
unusually low.

Rina is heading northwestward into an area of stronger expected
vertical wind shear. A combination of the circulation of Philippe
and a ridge centered over the eastern subtropical Atlantic should
keep Rina generally on a west-northwest to northwest heading for at
least a few days. After that, if Rina deepens or at least maintains
its current strength and structure, it could begin to lift
northward. However, if it weakens, Rina or its remnants will likely
turn westward by early next week. The wind shear should prevent Rina
from strengthening much, and could eventually lead to its
dissipation in as soon as 4 or 5 days. The NHC track forecast is
based heavily on a blend of the previous NHC forecast with the ECMWF
and GFS ensemble means, while the intensity forecast is close to the
IVCN consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 29/0300Z 18.4N 46.6W 35 KT 40 MPH
12H 29/1200Z 19.1N 47.3W 40 KT 45 MPH
24H 30/0000Z 19.6N 48.3W 45 KT 50 MPH
36H 30/1200Z 19.9N 49.4W 45 KT 50 MPH
48H 01/0000Z 20.4N 50.7W 40 KT 45 MPH
60H 01/1200Z 21.0N 52.4W 35 KT 40 MPH
72H 02/0000Z 22.0N 54.1W 35 KT 40 MPH
96H 03/0000Z 24.5N 57.0W 30 KT 35 MPH
120H 04/0000Z 27.0N 57.0W 30 KT 35 MPH

$$
Forecaster D. Zelinsky

[cycloneye]

Tropical Storm Rina Discussion Number 4
NWS National Hurricane Center Miami FL AL182023
500 AM AST Fri Sep 29 2023

Rina has become slightly better organized overnight. Deep,
persistent convection, with cloud top temperatures less than -80
degrees C, has mostly obscured the low-level circulation. While the
subjective satellite intensity estimates have risen this cycle to
45-55 kt, the objective estimates have generally held steady around
35 kt. The initial intensity is set to 40 kt to represent a blend
of these estimates.

The intensity forecast is still unusually complex and therefore,
unclear. While Rina appears to be gradually strengthening, most
models agree that Philippe, the tropical storm to its west, will
become the stronger storm. As Philippe becomes better organized,
Rina is expected to be sheared and subsequently weaken. By days 4
and 5, as Rina potentially moves away from the influence of
Philippe, the GFS and ECMWF do not show the environmental conditions
becoming any more conducive and continue to weaken Rina into a
remnant low. Only minor adjustments have been made to the latest
intensity forecast.

Rina's motion is estimated to be north-northwestward, or 340/4 kt.
The storm is expected to move generally west-northwestward to
northwestward through day 3. This is in part due to a binary
interaction with Philippe and a mid-level ridge over the eastern
subtropical Atlantic. Later in the forecast period, Rina is
forecast to turn north-northwestward to northward in the flow
between the subtropical ridge and an upper-level trough over the
western Atlantic. There is still a large spread in the model
solutions and thus, higher uncertainty in the track forecast, for
the latter part of the forecast period. The model guidance
envelope has generally shifted eastward this advisory cycle, and
the latest NHC track forecast has been nudged in this direction.
The official track forecast lies between the previous prediction and
consensus aids, TVCN and HCCA.


FORECAST POSITIONS AND MAX WINDS

INIT 29/0900Z 18.9N 46.6W 40 KT 45 MPH
12H 29/1800Z 19.3N 47.1W 45 KT 50 MPH
24H 30/0600Z 19.8N 48.1W 45 KT 50 MPH
36H 30/1800Z 20.4N 49.6W 45 KT 50 MPH
48H 01/0600Z 21.1N 51.0W 40 KT 45 MPH
60H 01/1800Z 22.0N 52.8W 35 KT 40 MPH
72H 02/0600Z 23.3N 54.3W 35 KT 40 MPH
96H 03/0600Z 26.0N 56.0W 30 KT 35 MPH
120H 04/0600Z 28.1N 55.6W 30 KT 35 MPH

$$
Forecaster Bucci

[cycloneye]

Tropical Storm Rina Discussion Number 5
NWS National Hurricane Center Miami FL AL182023
1100 AM AST Fri Sep 29 2023

Over the last few hours, Rina's center has become exposed with less
convective organization noted in the GOES-E satellite imagery. The
subjective satellite intensity estimates held steady at 45 kt,
while the objective estimates are lower around 35 to 40 kt. Based
on a blend of these data, the initial intensity is set to 40 kt.

Rina's current motion remains nearly the same, moving
north-northwestward at 335/5 kt. Most of the track guidance shows
Rina moving generally northwestward through the weekend between
nearby Tropical Storm Philippe and a subtropical ridge over the
central Atlantic. By early next week, Rina will start to make a turn
to the north within the flow between the subtropical ridge and an
upper-level trough moving across the western Atlantic. Most of the
model guidance shows a shift to the right of the previous forecast
track with a faster forward speed. The official NHC forecast track
reflects these trends and is adjusted closer to the latest consensus
aids. The one notable outlier is the GFS, which shows more of an
interaction between Rina and Philippe.

The exposed center of Rina indicates a sheared environment, and
strong deep-layer shear (partially associated with Philippe) is
forecast to persist during the next few days. The official NHC track
intensity is held steady through the next day or so, followed by
gradual weakening as supported by the latest intensity guidance. By
early next week, Rina is forecast to become a post-tropical remnant
low as it begins that turn to the north and open up into a trough by
day 5. Some model guidance suggests dissipation could occur even
sooner. The NHC intensity forecast is based on this weakening
trend, in agreement with the multi-model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 29/1500Z 19.4N 47.0W 40 KT 45 MPH
12H 30/0000Z 19.8N 47.6W 40 KT 45 MPH
24H 30/1200Z 20.4N 48.8W 40 KT 45 MPH
36H 01/0000Z 21.5N 50.3W 35 KT 40 MPH
48H 01/1200Z 22.7N 52.2W 35 KT 40 MPH
60H 02/0000Z 24.0N 53.8W 30 KT 35 MPH
72H 02/1200Z 25.6N 55.0W 30 KT 35 MPH
96H 03/1200Z 29.0N 55.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 04/1200Z...DISSIPATED

$$
Forecaster A. Reinhart/B. Reinhart

[cycloneye]

Tropical Storm Rina Discussion Number 6
NWS National Hurricane Center Miami FL AL182023
500 PM AST Fri Sep 29 2023

Strong northwesterly shear has caused the low-level center of Rina
to become completely exposed today. The overall convective structure
of the storm has deteriorated as well, with only small bursts of
deep convection observed in satellite images well downshear of its
center. An earlier scatterometer pass did not sample the core of the
system, but still showed 30-35 kt winds well removed from the center
in the southeast quadrant. The latest objective and subjective
satellite intensity estimates range from 30-45 kt, and the initial
intensity is conservatively held at 40 kt this afternoon. A full
scatterometer pass should be available this evening to better assess
the current intensity of Rina.

The tropical cyclone has turned northwestward and is accelerating,
with an initial motion of 320/8 kt. This general motion with a
slight increase in forward speed is expected during couple of days
while Rina moves around the northeastern periphery of the broader
circulation associated with Tropical Storm Philippe. Thereafter, the
shallow cyclone is forecast to separate from Philippe and turn
north-northwestward between a subtropical ridge to the east and an
approaching frontal system over the western Atlantic. There is still
large spread in the track guidance regarding the extent and speed of
this turn, with the GFS still on the western edge of the guidance.
With this uncertainty in mind, the updated NHC forecast remains
close to the HCCA and TVCA consensus aids and lies near the center
of the guidance envelope.

The strong wind shear currently affecting Rina is unlikely to relent
during the next couple of days. So despite warm SSTs along its path,
Rina seems unlikely to sustain a more organized convective structure
going forward, which is consistent with simulated satellite imagery
from the global models. The NHC intensity forecast shows gradual
weakening during the next several days, following the latest
multi-model intensity consensus aids. By 96 h, Rina is forecast to
open into a trough and/or merge with a frontal system. But if the
center remains decoupled from the convection, it is possible that
Rina degenerates into a remnant low even sooner than forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 29/2100Z 20.0N 47.8W 40 KT 45 MPH
12H 30/0600Z 20.5N 48.8W 40 KT 45 MPH
24H 30/1800Z 21.4N 50.2W 40 KT 45 MPH
36H 01/0600Z 22.8N 52.0W 35 KT 40 MPH
48H 01/1800Z 24.4N 53.8W 35 KT 40 MPH
60H 02/0600Z 25.9N 55.1W 30 KT 35 MPH
72H 02/1800Z 27.8N 55.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 03/1800Z...DISSIPATED

$$
Forecaster B. Reinhart/A. Reinhart

[cycloneye]

Tropical Storm Rina Discussion Number 7
NWS National Hurricane Center Miami FL AL182023
1100 PM AST Fri Sep 29 2023

Rina continues to produce persistent but poorly organized shower and
thunderstorm activity well to the east of its exposed surface
center. Despite the apparent lack of organization, a pair of ASCAT
passes near 00Z revealed that Rina's wind field was both slightly
larger and stronger than previously estimated. Both ASCAT passes
showed a large swath of winds of 40-45 kt east and northeast of
Rina's center. Based on this new information, the intensity of Rina
has been increased to 45 kt. Both ASCAT passes had slightly higher
winds in the deep convection that were flagged as marginal for
rain contamination, so they weren't considered as representative.
That said, its possible 45 kt could be slightly conservative.

With SHIPS-analyzed 850-200 mb shear higher than 40 kt for the next
24 h, its very unlikely Rina will become any better organized than
it is now. Nearly all of the dynamical models forecast that Rina
will dissipate in the next 24 to 48 h. Based on the structure
information provided by ASCAT, it appears unlikely that the tropical
storm will dissipate that quickly. Therefore the the NHC official
forecast is a little more conservative, but still shows Rina slowly
weakening, close to the intensity consensus. It is worth noting that
the vortex tracker associated with a few models flipped to Philippe
beyond 72 h and the tracks are therefore not representative of the
actual model forecast.

Rina is heading northwestward near 10 kt. The combination of
Tropical Storm Philippe to its west-southwest and a subtropical
ridge to the northeast should keep Rina on this general heading for
a couple of days. The NHC track forecast is near the center of the
guidance envelope, between the simple and corrected consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0300Z 20.4N 48.8W 45 KT 50 MPH
12H 30/1200Z 21.1N 50.2W 45 KT 50 MPH
24H 01/0000Z 22.2N 51.9W 40 KT 45 MPH
36H 01/1200Z 23.3N 53.7W 35 KT 40 MPH
48H 02/0000Z 24.8N 55.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 02/1200Z 26.7N 56.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 03/0000Z...DISSIPATED

$$
Forecaster D. Zelinsky

[cycloneye]

Tropical Storm Rina Discussion Number 8
NWS National Hurricane Center Miami FL AL182023
500 AM AST Sat Sep 30 2023

Rina remains a sheared tropical cyclone. Deep bursts of convection
have been flaring to the southeast of an exposed low-level
circulation. However, recent trends in geostationary satellite
imagery have shown the convection shrinking in areal coverage and
becoming shallower. The latest subjective Dvorak intensity
estimates were T3.0 (45 kt) and T2.5 (35 kt) from TAFB and SAB,
respectively. The initial intensity is held at a possibly
generous 45 kt in deference to the earlier scatterometer pass and
the latest TAFB estimate.

It is unlikely Rina will regain significant convective organization.
Global model guidance indicates that the deep-layer vertical wind
shear is likely to remain strong for the entirety of the forecast
period. Simulated satellite imagery shows convection attempting
to re-form near the center for the next couple of days, but it is
quickly stripped away by the strong upper-level winds. The NHC
intensity forecast shows Rina gradually weakening and becoming a
remnant low in 48 h.

Rina is moving to the west-northwest at 9 kt. Tropical Storm
Philippe, to its west-southwest, and a subtropical mid-level ridge
to the northeast are likely to steer Rina generally
west-northwestward to northwestward through 48 h. Only minor
adjustments have been made to the latest track forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 20.9N 49.5W 45 KT 50 MPH
12H 30/1800Z 21.7N 50.9W 40 KT 45 MPH
24H 01/0600Z 22.9N 52.8W 40 KT 45 MPH
36H 01/1800Z 24.2N 54.6W 35 KT 40 MPH
48H 02/0600Z 26.0N 56.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 02/1800Z 27.6N 56.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 03/0600Z...DISSIPATED

$$
Forecaster Bucci

[cycloneye]

Tropical Storm Rina Discussion Number 9
NWS National Hurricane Center Miami FL AL182023
1100 AM AST Sat Sep 30 2023

Satellite images show that Rina remains disorganized with any deep
convection sheared off well southeast of the center. Intensity
estimates are dropping, and ASCAT just came in with maximum winds
just above 35 kt, so the initial wind speed is set to 40 kt.
Strong shear should continue near the cyclone until it dissipates
in 2-3 days. Model guidance is in relatively good agreement on
this scenario, and the new intensity forecast is lower than before,
showing remnant low status as the weekend closes.

Rina continues moving west-northwestward, now at 10 kt. The storm
should rotate northwestward and northward on the northern side of
Philippe for the next couple of days. Thereafter, a weakened Rina
is forecast to degenerate into a trough of low pressure as it moves
into the subtropics. The new track forecast is very similar to the
last forecast, with no big changes to the guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 30/1500Z 21.2N 50.4W 40 KT 45 MPH
12H 01/0000Z 22.1N 51.8W 35 KT 40 MPH
24H 01/1200Z 23.5N 53.7W 30 KT 35 MPH
36H 02/0000Z 25.0N 55.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 02/1200Z 27.0N 56.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 03/0000Z...DISSIPATED

$$
Forecaster Blake

[cycloneye]

Tropical Storm Rina Discussion Number 10
NWS National Hurricane Center Miami FL AL182023
500 PM AST Sat Sep 30 2023

Visible satellite imagery shows the exposed center of Rina is well
displaced from deep convection, as strong northwesterly shear
continues to impact the storm. The intensity is held at a possibly
generous 40 kt for this advisory, which is a blend of the subjective
and objective satellite estimates.

The intensity forecast shows gradual weakening through Sunday. Given
Rina's structural trends today, and model simulated IR satellite
data over the next couple of days, the forecast shows Rina
degenerating into a remnant low Sunday evening. The strong shear as
diagnosed by SHIPS is expected to continue impacting Rina and its
remnants until the cyclone dissipates early next week. Even if the
shear isn't enough to prevent convective reformation, Rina will
likely struggle with dry mid-level relative humidities.

Rina is now moving northwestward at a slightly faster 12 kt. The
storm or its remnant low should continue to track northwestward and
then northward along the northern periphery of Philippe for the next
couple of days. The new track forecast is very similar to the
previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 30/2100Z 22.6N 51.5W 40 KT 45 MPH
12H 01/0600Z 23.5N 53.1W 35 KT 40 MPH
24H 01/1800Z 25.1N 54.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 02/0600Z 27.0N 55.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 02/1800Z 29.0N 55.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 03/0600Z...DISSIPATED

$$
Forecaster Mahoney/Blake

[cycloneye]

Tropical Storm Rina Discussion Number 11
NWS National Hurricane Center Miami FL AL182023
1100 PM AST Sat Sep 30 2023

Satellite imagery this evening indicates that Rina is maintaining a
well-defined center of circulation. However, strong northwesterly
vertical shear continues to impact the storm, resulting in
short-lived, episodic convection in the southeastern quadrant of the
circulation. Based on the limited convective activity, as well as
subjective and objective satellite estimates, the intensity for this
advisory is lowered to 35 kt.

Not much has changed with the intensity forecast, with all reliable
consensus aids suggesting that Rina will continue to gradually
weaken. The large-scale environment appears unfavorable for further
intensification due to low mid-level humidity and continued
moderate northwesterly wind shear, as well as the detrimental
influence of nearby Tropical Storm Philippe. Thus, the NHC forecast
shows Rina gradually weakening through tomorrow and degenerating
into a remnant low on Sunday.

Rina is continuing to track northwestward at approximately 12 kt.
The storm is expected to continue on this trajectory tonight, with a
turn to the north expected tomorrow. Early next week, Rina or its
remnants will accelerate northeastward between a mid-level ridge to
its east and an upper-level trough to its west. The new track
forecast is very similar to both the previous NHC forecast and the
consensus aids HCCA and TVCN.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0300Z 23.5N 52.8W 35 KT 40 MPH
12H 01/1200Z 24.7N 54.3W 30 KT 35 MPH
24H 02/0000Z 26.5N 55.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 02/1200Z 28.7N 55.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 03/0000Z 31.1N 54.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 03/1200Z...DISSIPATED

$$
Forecaster Hogsett/Pasch

[cycloneye]

Tropical Storm Rina Discussion Number 12
NWS National Hurricane Center Miami FL AL182023
500 AM AST Sun Oct 01 2023

Strong northwesterly shear continues to take a toll on Rina. The
cyclone has been producing an area of deep convection overnight,
but it is disorganized and located well southeast of the exposed
center. Any convection that has occurred near the center during
the past 12-18 hours has been very short-lived. Given the tight
circulation that is noted in infrared satellite imagery, the
initial wind speed is held at a possibly generous 35 kt for this
advisory. Scatterometer data later this morning should help to
determine if Rina is still producing tropical-storm-force winds.

Environmental conditions consisting of moderate to strong vertical
wind shear and dry mid-level air should cause gradual weakening
during the next day or two. Rina is forecast to become a remnant
low later today or tonight, and the global models indicate that the
circulation will open up into a trough of low pressure and
dissipate within a couple of days.

Rina is moving northwestward at about 12 kt. The cyclone is
expected to turn northward later today as it is steered between a
low- to mid-level ridge to its northeast and a mid-tropospheric
trough over the western Atlantic. The latest NHC track forecast is
near the center of the guidance envelope, which is slightly east of
the previous advisory.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0900Z 24.3N 53.7W 35 KT 40 MPH
12H 01/1800Z 25.6N 55.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 02/0600Z 27.7N 55.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 02/1800Z 30.4N 54.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 03/0600Z...DISSIPATED

$$
Forecaster Brown

[cycloneye]

Tropical Storm Rina Discussion Number 13
NWS National Hurricane Center Miami FL AL182023
1100 AM AST Sun Oct 01 2023

Despite continued northwesterly shear, a small area of deep
convection has persisted to the south and southeast of the center of
Rina this morning. The low-level center remains exposed in visible
satellite images, and recent ASCAT data suggests the center is
becoming less defined with weak winds noted on the southwest side of
the circulation. Based on the scatterometer winds, the initial
intensity is held at 35 kt for this advisory, with the strongest
winds confined to the southeastern quadrant of the storm.

Rina is still moving northwestward at 320/13 kt. The system is
expected to turn more northward later today and tonight while it
moves around the periphery of a subtropical ridge over the central
Atlantic. The track models are in good agreement, and the updated
NHC forecast is very similar to the previous one. The environmental
conditions are forecast to remain hostile going forward, and Rina is
forecast to gradually weaken over the next day or so due to the
negative influences of moderate to strong wind shear and dry
mid-level air. Simulated satellite imagery from the global models
suggest Rina could become a post-tropical remnant low by tonight,
and the system is forecast to open into a trough of low pressure and
dissipate by late Monday.


FORECAST POSITIONS AND MAX WINDS

INIT 01/1500Z 25.3N 54.8W 35 KT 40 MPH
12H 02/0000Z 26.8N 55.2W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 02/1200Z 29.3N 54.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 03/0000Z...DISSIPATED

$$
Forecaster Reinhart

[cycloneye]

Tropical Depression Rina Discussion Number 14
NWS National Hurricane Center Miami FL AL182023
500 PM AST Sun Oct 01 2023

Rina is barely a tropical cyclone. Its associated sheared convection
collapsed a few hours ago, and the fully exposed low-level center
has continued to lose definition based on recent GOES derived motion
wind (DMW) vectors. Assuming some weakening has occurred since the
earlier scatterometer passes, the initial intensity is lowered to 30
kt for this advisory.

The initial motion of Rina is still northwestward (325/14 kt), but
the shallow cyclone is expected to turn northward soon while moving
around the western extent of a low-level ridge. The continued
northwesterly shear and dry air in the surrounding environment are
expected to limit convective development going forward, and Rina
is likely to degenerate to a remnant low or open into a trough
during the next 12-24 h. No notable changes were made to the NHC
track or intensity forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 01/2100Z 26.2N 55.5W 30 KT 35 MPH
12H 02/0600Z 28.2N 55.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 02/1800Z...DISSIPATED

$$
Forecaster Reinhart

[cycloneye]

BULLETIN
Post-Tropical Cyclone Rina Advisory Number 15
NWS National Hurricane Center Miami FL AL182023
1100 PM AST Sun Oct 01 2023

...DEPRESSION BECOMES A REMNANT LOW...
...THIS IS THE LAST ADVISORY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.1N 55.4W
ABOUT 785 MI...1265 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1010 MB...29.83 INCHES

Post-Tropical Cyclone Rina Discussion Number 15
NWS National Hurricane Center Miami FL AL182023
1100 PM AST Sun Oct 01 2023

The depression's surface circulation has become increasingly diffuse
this evening while the cyclone has been devoid of organized deep
convection for over 18 hours. Only a few small intermittent bursts
of convection have been present just to the east and south of the
center during the past couple of hours. Therefore, this is the final
advisory on Rina, and the system is now considered to be a
post-tropical remnant low and is likely to open up into a surface
trough on Monday.

The initial motion of the low-level cloud swirl is moving
northward, or 010/11 kt, and this general motion should continue
until the remnants of Rina completely dissipate over the central
subtropical Atlantic.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0300Z 27.1N 55.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
12H 02/1200Z 28.9N 54.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 03/0000Z...DISSIPATED

$$
Forecaster Roberts