EPAC: ROSLYN - Post-Tropical

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Re: EPAC: EIGHTEEN-E - Tropical Depression

#21 Postby Yellow Evan » Mon Sep 26, 2016 7:20 am

Looks much better this morning.
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Re: EPAC: ROSLYN - Tropical Storm

#22 Postby cycloneye » Mon Sep 26, 2016 9:50 am

TROPICAL STORM ROSLYN DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
800 AM PDT MON SEP 26 2016

Roslyn remains a large, but sheared tropical storm. An 0847 UTC
AMSR microwave overpass indicates that the low-level center is
located well to west of the large area of deep convection, due to
moderate southwesterly shear. Dvorak intensity estimates from
TAFB and SAB are unchanged from before, so the initial intensity
is kept at 35 kt for this advisory. The southwesterly shear that
is currently affecting the cyclone is predicted to increase during
the next 24 hours, which should prevent significant strengthening
while Roslyn remains over marginally warm water. In a little
more than 24 hours, the tropical storm will be crossing the 26 deg C
isotherm and moving into a more stable air mass, which should begin
the weakening process. The NHC forecast shows Roslyn becoming a
remnant low within 48 hours, and dissipating by the end of the
forecast period.

Recent fixes suggest that Roslyn is moving north-northeastward
or 015/4 kt. The tropical storm should turn northeastward today in
the southwesterly flow between a mid-level ridge to the southeast
and a large mid- to upper-level low over the Baja California
peninsula. After Roslyn weakens into a shallow remnant low, it
should turn northward and then northwestward in the low-level flow
west of the Baja peninsula. The new NHC track forecast is very
similar to the previous advisory, and is a blend of the GFS, ECMWF,
and GFS ensemble mean.


FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 17.0N 119.4W 35 KT 40 MPH
12H 27/0000Z 17.5N 119.0W 35 KT 40 MPH
24H 27/1200Z 18.5N 118.1W 35 KT 40 MPH
36H 28/0000Z 19.7N 117.3W 30 KT 35 MPH
48H 28/1200Z 21.0N 117.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/1200Z 23.2N 118.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 30/1200Z 24.5N 119.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 01/1200Z...DISSIPATED

$$
Forecaster Brown
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Re: EPAC: ROSLYN - Tropical Storm

#23 Postby Yellow Evan » Mon Sep 26, 2016 1:54 pm

26/1730 UTC 16.9N 119.2W T2.5/2.5 ROSLYN -- East Pacific
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Re: EPAC: ROSLYN - Tropical Storm

#24 Postby cycloneye » Mon Sep 26, 2016 3:42 pm

TROPICAL STORM ROSLYN DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
200 PM PDT MON SEP 26 2016

Although the center of Roslyn has become farther separated
from the deep convection this afternoon due to strong
southwesterly shear, recent ASCAT data indicate that the
tropical cyclone is stronger than previously estimated. The
1756 UTC ASCAT overpass revealed 40-45 kt winds, and a much
larger area of 34-kt winds than analyzed earlier. Based on
these data, the initial intensity has been set at 45 kt, and
the 34-kt wind radii have been expanded accordingly.

Increasing southwesterly vertical wind shear and gradually
decreasing SSTs should cause weakening, but given the large size of
the system the spindown process is likely to be more gradual than
average. In 24 to 36 hours, much cooler waters and a more stable
airmass are expected to cause Roslyn to degenerate into a remnant
low and to dissipate in 3 to 4 days. The NHC intensity forecast has
been adjusted upward in the early portion of the forecast to account
for the higher initial intensity, but is unchanged thereafter. The
official forecast shows a slower rate of decay than the SHIPS
guidance, but it is general agreement with the trend in the global
models.

Roslyn has not moved much during the past 24 hours, and the best
estimate of the initial motion is 035/2 kt. The models insist that
Roslyn will begin moving northeastward within deep layer
southwesterly flow between a mid-level ridge to the southeast and a
large upper-level low over Baja California. In a couple of days,
the cyclone should turn northward, then northwestward once it
weakens and is steered by the low-level flow. The new NHC track is
similar to the previous advisory and is near a consensus of the
ECMWF and GFS models.

FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 16.8N 118.8W 45 KT 50 MPH
12H 27/0600Z 17.3N 118.4W 40 KT 45 MPH
24H 27/1800Z 18.4N 117.7W 35 KT 40 MPH
36H 28/0600Z 19.8N 117.3W 30 KT 35 MPH
48H 28/1800Z 21.2N 117.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/1800Z 23.3N 118.8W 20 KT 25 MPH...DISSIPATED
96H 30/1800Z...DISSIPATED

$$
Forecaster Brown
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Re: EPAC: ROSLYN - Tropical Storm

#25 Postby euro6208 » Mon Sep 26, 2016 8:35 pm

Image
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Remember, all of my post aren't official. For official warnings and discussions, Please refer to your local NWS products...

NWS for the Western Pacific

http://www.prh.noaa.gov/guam/

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Re: EPAC: ROSLYN - Tropical Storm

#26 Postby cycloneye » Mon Sep 26, 2016 10:02 pm

TROPICAL STORM ROSLYN DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
800 PM PDT MON SEP 26 2016

Southwesterly shear of about 20 kt is currently affecting Roslyn,
and this has caused the associated convection to be confined to the
north and northeast portions of the large circulation. The initial
wind speed is held at 45 kt, based on the earlier ASCAT data, but
the satellite presentation suggests that this could be a little
generous. Weakening is expected to begin soon due to a further
increase in shear and continued dry air entrainment. Roslyn will
likely become a remnant low in 36 to 48 hours when it moves over
sea surface temperatures lower than 26 deg C. The NHC intensity
forecast is identical to the previous one, and generally follows
the global model guidance.

Visible satellite images and microwave data suggest that Roslyn is
moving east-northeastward at 4 kt. During the next day or so, the
tropical storm is expected to move northeastward in the flow between
a large mid- to upper-level cut off low near the northern Baja
California peninsula and a ridge over central Mexico. After that
time, a turn to the north and northwest is expected when the
shallow cyclone becomes influenced by the low-level flow. The NHC
track forecast is adjusted a little to the east of the previous
one, trending toward the latest consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0300Z 17.2N 118.4W 45 KT 50 MPH
12H 27/1200Z 17.9N 117.7W 40 KT 45 MPH
24H 28/0000Z 19.1N 117.0W 35 KT 40 MPH
36H 28/1200Z 20.5N 116.9W 30 KT 35 MPH
48H 29/0000Z 21.7N 117.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 30/0000Z 23.5N 118.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 01/0000Z...DISSIPATED

$$
Forecaster Cangialosi
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Re: EPAC: ROSLYN - Tropical Storm

#27 Postby cycloneye » Tue Sep 27, 2016 5:08 am

TROPICAL STORM ROSLYN DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
200 AM PDT TUE SEP 27 2016

Roslyn's center appears to be losing some definition in infrared
satellite imagery, and all of the associated deep convection is
displaced to the north and northeast due to strong southwesterly
shear. Roslyn fell within the nadir gap of the latest ASCAT
passes, but the initial intensity is set at 40 kt based on a
gradual lowering of subjective and objective Dvorak estimates.
This value is also in accordance with the most recent UW-CIMSS
SATCON estimate. Increasing shear, gradually cooling SSTs, and dry
mid-level air should induce additional weakening, and deep
convection is likely to dissipate within the next day or two.
The new NHC intensity forecast shows Roslyn becoming a remnant low
in 36 hours, and it is expected to open up into a trough by day 4.

The initial motion is now northeastward, or 050/6 kt. Roslyn is
expected to turn northward toward a deep-layer low located over the
Baja California peninsula during the next 36 hours. It should then
turn northwestward and west-northwestward on days 2 and 3 after it
has become a remnant low, steered by lower-level ridging. The
official track forecast has again been nudged east of the previous
advisory toward the latest TVCN multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 17.8N 117.7W 40 KT 45 MPH
12H 27/1800Z 18.7N 117.1W 35 KT 40 MPH
24H 28/0600Z 20.0N 116.6W 30 KT 35 MPH
36H 28/1800Z 21.3N 116.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 29/0600Z 22.3N 117.3W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 30/0600Z 23.5N 119.5W 15 KT 15 MPH...POST-TROP/REMNT LOW
96H 01/0600Z...DISSIPATED

$$
Forecaster Berg
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Re: EPAC: ROSLYN - Tropical Storm

#28 Postby Yellow Evan » Tue Sep 27, 2016 11:15 am

000
WTPZ43 KNHC 271439
TCDEP3

TROPICAL STORM ROSLYN DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
800 AM PDT TUE SEP 27 2016

Roslyn continues to be affected by strong southwesterly shear, with
the center of the tropical cyclone exposed to the southwest of the
associated deep convection. The initial intensity remains 40 kt
for this advisory, which is an average of Dvorak estimates of
45 kt and 35 kt, from TAFB and SAB, respectively. Roslyn should
slowly weaken due to increasing southwesterly shear, gradually
decreasing SSTs, and dry mid-level air that is wrapping around
the western portion of the circulation. The updated NHC
intensity forecast is unchanged from the previous advisory and
calls for Roslyn to become a remnant low in 36 hours, and
dissipate in 3 to 4 days.

Recent satellite fixes indicate that Roslyn is moving northeastward
or 045/7 kt. The tropical storm is forecast to turn northward by
tonight around the eastern portion of a mid- to upper-level trough
extending southwestward from a large cut-off low over northwestern
Mexico. By late Wednesday, a weaker and more vertically shallow
Roslyn is expected to turn northwestward. There is more spread in
the track models this morning, but little change was required
to the NHC forecast which is located near the middle of the guidance
envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 27/1500Z 18.3N 117.3W 40 KT 45 MPH
12H 28/0000Z 19.3N 116.9W 35 KT 40 MPH
24H 28/1200Z 20.6N 116.7W 30 KT 35 MPH
36H 29/0000Z 21.8N 117.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 29/1200Z 22.6N 118.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 30/1200Z 23.5N 120.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
96H 01/1200Z...DISSIPATED

$$
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Re: EPAC: ROSLYN - Tropical Storm

#29 Postby cycloneye » Tue Sep 27, 2016 9:46 pm

TROPICAL STORM ROSLYN DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
800 PM PDT TUE SEP 27 2016

Roslyn is weakening this evening. Strong southwesterly shear of
nearly 30 kt is affecting the tropical storm, and this has caused
the associated deep convection to be well removed to the
north-northeast of the center. The initial intensity is
lowered a little to 35 kt, based on the latest Dvorak
classifications from TAFB, SAB, and automated values from CIMSS at
the University of Wisconsin. The shear is expected to persist, or
even increase a little, during the next few days. These hostile
winds combined with a stable atmosphere and decreasing sea surface
temperatures should cause additional weakening. Roslyn will likely
weaken to a depression overnight or on Wednesday and become a
remnant low shortly thereafter when it moves over sea surface
temperatures below 26 deg C. The NHC intensity forecast is the same
as the previous one, and generally follows the global model
guidance.

The initial motion estimate is 040/8 kt. Roslyn should turn
northward soon as it rotates around a large cut off mid- to
upper-level low near the northern Baja California peninsula. Once
the cyclone becomes a remnant low, it should turn northwestward in
the low-level flow before it dissipates in 2 to 3 days. The
new NHC track forecast is a little to the east of the previous one,
and lies closest to a consensus of the GFS and ECMWF models.

FORECAST POSITIONS AND MAX WINDS

INIT 28/0300Z 19.5N 115.9W 35 KT 40 MPH
12H 28/1200Z 20.7N 115.9W 30 KT 35 MPH
24H 29/0000Z 21.8N 116.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 29/1200Z 22.8N 116.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 30/0000Z 23.6N 117.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 01/0000Z...DISSIPATED

$$
Forecaster Cangialosi
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Re: EPAC: ROSLYN - Post-Tropical

#30 Postby cycloneye » Thu Sep 29, 2016 10:32 am

POST-TROPICAL CYCLONE ROSLYN DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
800 AM PDT THU SEP 29 2016

Roslyn has been devoid of deep convection overnight, and the system
consists of only a swirl of low clouds. Given the lack of
convection, Roslyn has become a post-tropical remnant low. The
initial intensity is kept at 25 kt based on continuity from earlier
scatterometer data. The cyclone should spin down over cool waters
and completely dissipate after 24 hours.

The motion is north-northwestward or 345/6 kt. A weak low-level
ridge to the north and northwest of the system should cause a turn
toward the northwest and west-northwest until dissipation.

This is the last advisory on Roslyn. For additional information on
the remnant low please see High Seas Forecasts issued by the
National Weather Service, under AWIPS header NFDHSFEPI, WMO header
FZPN02 KWBC, and on the web at
http://www.opc.ncep.noaa.gov/shtml/NFDHSFEPI.shtml.

FORECAST POSITIONS AND MAX WINDS

INIT 29/1500Z 23.5N 115.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
12H 30/0000Z 24.1N 116.2W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 30/1200Z 24.4N 117.4W 15 KT 15 MPH...POST-TROP/REMNT LOW
36H 01/0000Z...DISSIPATED

$$
Forecaster Pasch
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