EPAC: XAVIER - Post-Tropical

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EPAC: XAVIER - Post-Tropical

#1 Postby Extratropical94 » Thu Nov 01, 2018 3:12 am

94E INVEST 181101 0600 11.4N 111.5W EPAC 25 1008

An elongated low pressure system located several hundred miles south
of the southern tip of the Baja California peninsula is producing a
broad area of disorganized showers and thunderstorms. Environmental
conditions are forecast to be conducive for gradual development
during the next several days, and a tropical depression is likely to
form later this week or this weekend while the system moves slowly
northwestward to northward.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...90 percent.
Last edited by Extratropical94 on Fri Nov 02, 2018 4:57 pm, edited 1 time in total.
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Re: EPAC: INVEST 94E

#2 Postby cycloneye » Thu Nov 01, 2018 12:53 pm

Shower activity associated with an area of low pressure centered
about 700 miles south of the southern tip of the Baja California
Peninsula has become better organized during the past several
hours. Environmental conditions are forecast to be conducive for
additional development during the next several days, and a tropical
depression is likely to form during the next few days while the
system moves slowly northward or northeastward.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.
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Re: EPAC: INVEST 94E

#3 Postby cycloneye » Thu Nov 01, 2018 6:44 pm

1. A low pressure system centered about 700 miles south of the southern
tip of the Baja California Peninsula has become better defined
since yesterday. Shower and thunderstorm activity is beginning to
show some signs of organization, and environmental conditions are
forecast to be conducive for the development of a tropical
depression during the next day or so while the system moves slowly
northward or northeastward.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.
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Re: EPAC: INVEST 94E

#4 Postby galaxy401 » Fri Nov 02, 2018 1:27 pm

Xavier is coming.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Fri Nov 2 2018

For the eastern North Pacific...east of 140 degrees west longitude:

Satellite imagery indicates that shower activity associated with
the low pressure area centered about 600 miles south of the
southern tip of the Baja California peninsula has become better
organized, and that the circulation of the low is becoming better
defined. If current trends continue, advisories will be initiated
on a tropical depression this afternoon or tonight as the system
moves northeastward. Interests along the southwestern coast of
mainland Mexico should monitor the progress of this system
* Formation chance through 48 hours...high...near 100 percent.
* Formation chance through 5 days...high...near 100 percent.
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Re: EPAC: INVEST 94E

#5 Postby zeehag » Fri Nov 02, 2018 1:43 pm

our xavier wannabe..... watching closely
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Re: EPAC: Tropical Depression 25-E

#6 Postby Kingarabian » Fri Nov 02, 2018 3:44 pm

Tropical Depression Twenty-Five-E Discussion Number 1
NWS National Hurricane Center Miami FL EP252018
300 PM MDT Fri Nov 02 2018

Microwave data received during the past several hours indicate that
the broad area of low pressure we've been monitoring southwest of
the coast of Mexico has developed a sufficiently well-defined center
of circulation and improved low-level curved bands. Visible images,
however, still suggest that multiple swirls are revolving around a
common center, with the deepest convection offset to the east of
that center due to southwesterly shear. Now that the system has a
well-defined center, advisories are being initiated on Tropical
Depression Twenty-Five-E, with maximum winds of 30 kt based on
Dvorak classifications of T2.0 and T1.5.

Although the depression should remain over sufficiently warm waters
to support strengthening, southwesterly shear is expected to
increase from its current value of about 15 kt to over 25 kt during
the next couple of days. Therefore, only some intensification is
anticipated during the next 36 hours or so, with weakening beginning
by day 3. The system is likely to degenerate into a remnant low in
4 or 5 days once it can no longer produce organized deep convection.
The statistical-dynamical guidance show little to no strengthening,
so this initial forecast most closely follows the HWRF, HCCA, and
GFS models.

The depression appears to be moving east-northeastward, or 75
degrees, at about 7 kt. The depression is trapped between two
mid-tropospheric ridges to its east and west, and to the south of an
expansive mid-level trough which extends across much of Mexico and
the Gulf of Mexico. The resulting steering pattern should cause the
cyclone to move slowly northeastward and then northward toward the
trough during the next 48 hours, but the system should then turn
sharply westward on days 4 and 5 once it becomes a shallower system
and is steered by lower-level easterly flow. The UKMET model is the
main outlier among the model guidance, showing the system reaching
the coast of southwestern Mexico, but it appears to keep the
circulation too deep in the face of strong southwesterly shear. The
NHC track forecast is therefore just slightly left of the TVCN
multi-model consensus and the HCCA model, keeping the cyclone well
offshore of the coast of Mexico.


FORECAST POSITIONS AND MAX WINDS

INIT 02/2100Z 14.4N 109.0W 30 KT 35 MPH
12H 03/0600Z 14.7N 108.3W 35 KT 40 MPH
24H 03/1800Z 15.2N 107.6W 40 KT 45 MPH
36H 04/0600Z 15.9N 107.1W 45 KT 50 MPH
48H 04/1800Z 16.7N 107.0W 45 KT 50 MPH
72H 05/1800Z 17.5N 107.4W 35 KT 40 MPH
96H 06/1800Z 17.8N 109.0W 30 KT 35 MPH
120H 07/1800Z 18.0N 111.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg
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Re: EPAC: Tropical Depression 25-E

#7 Postby cycloneye » Fri Nov 02, 2018 3:45 pm

BULLETIN
Tropical Depression Twenty-Five-E Advisory Number 1
NWS National Hurricane Center Miami FL EP252018
300 PM MDT Fri Nov 02 2018

...LATE-SEASON TROPICAL DEPRESSION FORMS SOUTHWEST OF MEXICO...


SUMMARY OF 300 PM MDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...14.4N 109.0W
ABOUT 445 MI...715 KM SW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...ENE OR 75 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES


Tropical Depression Twenty-Five-E Discussion Number 1
NWS National Hurricane Center Miami FL EP252018
300 PM MDT Fri Nov 02 2018

Microwave data received during the past several hours indicate that
the broad area of low pressure we've been monitoring southwest of
the coast of Mexico has developed a sufficiently well-defined center
of circulation and improved low-level curved bands. Visible images,
however, still suggest that multiple swirls are revolving around a
common center, with the deepest convection offset to the east of
that center due to southwesterly shear. Now that the system has a
well-defined center, advisories are being initiated on Tropical
Depression Twenty-Five-E, with maximum winds of 30 kt based on
Dvorak classifications of T2.0 and T1.5.

Although the depression should remain over sufficiently warm waters
to support strengthening, southwesterly shear is expected to
increase from its current value of about 15 kt to over 25 kt during
the next couple of days. Therefore, only some intensification is
anticipated during the next 36 hours or so, with weakening beginning
by day 3. The system is likely to degenerate into a remnant low in
4 or 5 days once it can no longer produce organized deep convection.
The statistical-dynamical guidance show little to no strengthening,
so this initial forecast most closely follows the HWRF, HCCA, and
GFS models.

The depression appears to be moving east-northeastward, or 75
degrees, at about 7 kt. The depression is trapped between two
mid-tropospheric ridges to its east and west, and to the south of an
expansive mid-level trough which extends across much of Mexico and
the Gulf of Mexico. The resulting steering pattern should cause the
cyclone to move slowly northeastward and then northward toward the
trough during the next 48 hours, but the system should then turn
sharply westward on days 4 and 5 once it becomes a shallower system
and is steered by lower-level easterly flow. The UKMET model is the
main outlier among the model guidance, showing the system reaching
the coast of southwestern Mexico, but it appears to keep the
circulation too deep in the face of strong southwesterly shear. The
NHC track forecast is therefore just slightly left of the TVCN
multi-model consensus and the HCCA model, keeping the cyclone well
offshore of the coast of Mexico.


FORECAST POSITIONS AND MAX WINDS

INIT 02/2100Z 14.4N 109.0W 30 KT 35 MPH
12H 03/0600Z 14.7N 108.3W 35 KT 40 MPH
24H 03/1800Z 15.2N 107.6W 40 KT 45 MPH
36H 04/0600Z 15.9N 107.1W 45 KT 50 MPH
48H 04/1800Z 16.7N 107.0W 45 KT 50 MPH
72H 05/1800Z 17.5N 107.4W 35 KT 40 MPH
96H 06/1800Z 17.8N 109.0W 30 KT 35 MPH
120H 07/1800Z 18.0N 111.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg


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Re: EPAC: TWENTY-FIVE-E - Tropical Depression

#8 Postby galaxy401 » Fri Nov 02, 2018 8:09 pm

Say hi to Xavier.

Location: 14.4°N 108.5°W
Maximum Winds: 35 kt Gusts: N/A
Minimum Central Pressure: 1006 mb
Environmental Pressure: 1011 mb
Radius of Circulation: 150 NM
Radius of Maximum Wind: 60 NM
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Re: EPAC: XAVIER - Tropical Storm

#9 Postby Extratropical94 » Fri Nov 02, 2018 9:59 pm

Tropical Storm Xavier Discussion Number 2
NWS National Hurricane Center Miami FL EP252018
900 PM MDT Fri Nov 02 2018

For the 22nd time this year, a tropical storm (Xavier) has formed
over the eastern North Pacific. The most recent intensity estimates
from TAFB and the UW-CIMSS SATCON support increasing the initial
intensity to 35 kt. Xavier is the first tropical storm to reach the
"X" name on the East Pacific namelist since 1992.

No changes of note were made to the intensity forecast. The tropical
storm is strongly sheared from the southwest and convective activity
is limited to the eastern semicircle of the cyclone. Although Xavier
should be located over warm waters for the next 5 days, strong
upper-level southwesterly flow will cause high wind shear across the
cyclone. The HWRF, HMON, and COAMPS-TC models all forecast that the
tropical storm could strengthen a little more over the next day or
so, while the statistical guidance indicates that Xavier is already
near its peak intensity. The NHC intensity forecast follows the
consensus and shows slight strengthening through the weekend. By
early next week, increased shear and a drier surrounding environment
will likely cause Xavier to weaken and become a remnant low.

It has been difficult to identify the center of Xavier this evening,
but it is estimated that the tropical storm is still moving
generally east-northeastward at around 7 kt. A weakness in the
subtropical ridge created by a large deep-layer trough extending
over central Mexico and the Gulf of Mexico should cause Xavier to
turn toward the northeast or north overnight and tomorrow. There has
been a shift in the GFS and its associated regional models, which
now show a farther northeast track of Xavier, closer to the coast of
Mexico. However, a majority of the dynamical models still show the
cyclone turning abruptly westward and away from land while it
weakens by early next week. Out of respect for the ECMWF and its
ensemble, which show a much farther west track for Xavier, the NHC
forecast has been nudged only slightly toward the northeast through
48 h and now lies a little to the west of the TVCE track consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 03/0300Z 14.5N 108.2W 35 KT 40 MPH
12H 03/1200Z 14.8N 107.5W 40 KT 45 MPH
24H 04/0000Z 15.6N 106.8W 45 KT 50 MPH
36H 04/1200Z 16.4N 106.5W 45 KT 50 MPH
48H 05/0000Z 17.1N 106.4W 45 KT 50 MPH
72H 06/0000Z 17.8N 107.0W 35 KT 40 MPH
96H 07/0000Z 17.5N 109.0W 30 KT 35 MPH
120H 08/0000Z 18.0N 111.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
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Re: EPAC: XAVIER - Tropical Storm

#10 Postby Nancy Smar » Sat Nov 03, 2018 1:41 am

EP, 25, 2018110306, , BEST, 0, 145N, 1079W, 35, 1006, TS
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Re: EPAC: XAVIER - Tropical Storm

#11 Postby Nancy Smar » Sat Nov 03, 2018 3:36 am

ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM

Tropical Storm Xavier Discussion Number 3
NWS National Hurricane Center Miami FL EP252018
300 AM MDT Sat Nov 03 2018

A large burst of deep convection has developed over the northeastern
and eastern portions of Xavier's circulation overnight. An earlier
GMI microwave overpass indicated that the center was located near
the southwestern edge of the convection, but there was evidence of
an increase in banding over the northeastern portion of the storm.
Dvorak data T-numbers from TAFB and SAB were T2.5 and T3.0,
respectively, so the initial intensity has been increased to
40 kt for this advisory.

Xavier is expected to remain embedded within an area of moderate
to strong southwesterly shear during the next 24 to 36 hours, and
these conditions are likely to prevent significant strengthening.
Although the statistical guidance shows no additional
intensification, the dynamical models deepen the system over the
next day or so, and the NHC forecast calls for a slight increase in
wind speed today, followed by little change in strength through
Sunday. This is in good agreement with the latest HFIP corrected
consensus model. By 48 hours the shear is expected to become even
stronger, and as a result, gradual weakening should occur
thereafter. Xavier is forecast to degenerate into a remnant low
by day 4, if not sooner.

The aforementioned microwave pass was very helpful in locating the
center of Xavier. Based on that data and recent satellite fixes,
the initial motion estimate is east-northeastward at about 6 kt.
The track forecast reasoning has not changed from the previous
advisory. Xavier should turn northeastward, then northward by
tonight toward a weakness in the subtropical ridge created by a
deep-layer trough over central Mexico. After Xavier weakens, the
cyclone should turn toward west-northwestward or westward as it
is steered by the low-level flow. Since there is still a fair
amount of spread among the track models as to how far north Xavier
will move before it weakens and turns westward, the NHC track is
close to the various consensus aids at 48 hours and beyond. Most
of the track models have trended a little faster after 48 hours,
and the official forecast has been adjusted accordingly.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 14.7N 107.7W 40 KT 45 MPH
12H 03/1800Z 15.2N 107.0W 45 KT 50 MPH
24H 04/0600Z 16.0N 106.4W 45 KT 50 MPH
36H 04/1800Z 16.6N 106.3W 45 KT 50 MPH
48H 05/0600Z 17.1N 106.5W 40 KT 45 MPH
72H 06/0600Z 17.5N 107.7W 30 KT 35 MPH
96H 07/0600Z 17.6N 110.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 08/0600Z 18.0N 112.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown

NNNN
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Re: EPAC: XAVIER - Tropical Storm

#12 Postby cycloneye » Sat Nov 03, 2018 9:48 am

Tropical Storm Xavier Discussion Number 4
NWS National Hurricane Center Miami FL EP252018
900 AM MDT Sat Nov 03 2018

Although Xavier is being affected by 20-25 kt of westerly vertical
shear, the cyclone continues to generate a large burst of convection
and the low-level center is now located under the southwestern edge
of the convective mass. The initial intensity is increased to 45
kt, which is at the upper end of the various satellite intensity
estimates.

During the next 24 h, the dynamical models suggest that an
upper-level trough located to the north and west of Xavier should
provide upper-level divergence over the cyclone. This could allow
some additional strengthening despite the ongoing shear. After
that time, the trough is forecast to dissipate, leaving the
tropical storm in an area of upper-level convergence and moderate
to strong shear that should cause it to weaken. Based on this
evolution, the intensity forecast calls for a little more
strengthening during the next 12-24 h, followed by gradual weakening
through the remainder of the forecast period, with the cyclone
becoming a remnant low in about 96 h. The forecast follows the
overall trend of the intensity guidance and lies near the upper edge
of the guidance.

Based on a combination of conventional and microwave satellite
fixes, the initial motion is estimated to be 060/7. There is again
little change to the forecast track philosophy. Xavier should turn
northeastward and then northward during the next 24 h toward a
weakness in the subtropical ridge created by the aforementioned
trough. As Xavier weakens and becomes a shallow system, the
cyclone should turn toward the west-northwest and west as it is
steered by the low-level flow to the south of the subtropical ridge.
The new forecast track is nudged just a little to the east and
north of the previous track, but it remains close to the various
consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 15.3N 107.0W 45 KT 50 MPH
12H 04/0000Z 15.8N 106.4W 50 KT 60 MPH
24H 04/1200Z 16.6N 106.0W 50 KT 60 MPH
36H 05/0000Z 17.3N 106.1W 45 KT 50 MPH
48H 05/1200Z 17.4N 106.5W 40 KT 45 MPH
72H 06/1200Z 17.5N 108.0W 30 KT 35 MPH
96H 07/1200Z 17.5N 111.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 08/1200Z 18.0N 113.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven
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Re: EPAC: XAVIER - Tropical Storm

#13 Postby zhukm29 » Sat Nov 03, 2018 2:39 pm

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Re: EPAC: XAVIER - Tropical Storm

#14 Postby HurricaneRyan » Sat Nov 03, 2018 3:36 pm

First X name storm in my lifetime . this is exciting!
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Re: EPAC: XAVIER - Tropical Storm

#15 Postby cycloneye » Sat Nov 03, 2018 3:40 pm

SUMMARY OF 300 PM MDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...15.6N 106.1W
ABOUT 265 MI...425 KM SSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


Tropical Storm Xavier Discussion Number 5
NWS National Hurricane Center Miami FL EP252018
300 PM MDT Sat Nov 03 2018

Xavier continues to show a sheared cloud pattern in conventional
satellite imagery this afternoon, with the low-level center located
near or just southwest of the main convective mass. The various
subjective and objective satellite intensity estimates are near 45
kt, and recent scatterometer data also indicate winds near 45 kt.
Thus, the initial intensity remains at that value. Analyses from
CIMSS and from the SHIPS model indicate that Xavier is still in an
environment of 20-25 kt of southwesterly vertical shear.

There is little change in the intensity forecast philosophy from the
last advisory. During the next 12-24 h, the dynamical models
suggest that an upper-level trough located to the north and west of
Xavier should provide upper-level divergence over the cyclone. This
could allow some additional strengthening despite the ongoing shear.
After that time, the trough is forecast to dissipate, leaving the
tropical storm in an area of upper-level convergence, moderate to
strong shear, and a dry surrounding air that should cause it to
weaken. Based on this evolution, the intensity forecast calls for a
little more strengthening early in the forecast, followed by gradual
weakening through the remainder of the forecast period. As in the
previous forecast, Xavier is expected to degenerate to a remnant low
in about 96 h. The forecast again follows the overall trend of the
intensity guidance and lies near the upper edge of the guidance
through 48 h.

The initial motion is now 060/8. As mentioned previously, Xavier
should turn northeastward and then northward during the next 24 h
toward a weakness in the subtropical ridge created by the
aforementioned trough. As Xavier weakens and becomes a shallow
system, the cyclone should turn toward the west-northwest and west
as it is steered by the low-level flow to the south of the
subtropical ridge. All of the dynamical models follow this
scenario except for the UKMET, which shows a much more northward
motion toward the southern Gulf of California. The new forecast
track will follow the model consensus in showing the westward
motion, and the new NHC forecast track is similar to the previous
track.


FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 15.6N 106.1W 45 KT 50 MPH
12H 04/0600Z 16.1N 105.7W 50 KT 60 MPH
24H 04/1800Z 16.9N 105.7W 50 KT 60 MPH
36H 05/0600Z 17.3N 106.1W 45 KT 50 MPH
48H 05/1800Z 17.5N 106.8W 40 KT 45 MPH
72H 06/1800Z 18.0N 109.5W 30 KT 35 MPH
96H 07/1800Z 18.0N 112.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 08/1800Z 18.5N 114.0W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven


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Re: EPAC: XAVIER - Tropical Storm

#16 Postby cycloneye » Sat Nov 03, 2018 9:41 pm

Tropical Storm Xavier Discussion Number 6
NWS National Hurricane Center Miami FL EP252018
1000 PM CDT Sat Nov 03 2018

Xavier's overall structure has not changed since this afternoon. The
tropical storm is still strongly sheared and deep convection is
primarily occurring to the northeast of its low-level center. Recent
objective and subjective intensity estimates range from 45 to 50 kt.
Earlier ASCAT data explicitly contained several vectors near 45 kt,
but the instrument could have under-sampled the maximum winds. Based
on all these data, 50 kt seems most representative of the tropical
storm's intensity at this time.

Regardless of Xavier's exact maximum winds, it is likely nearing its
peak intensity now. Some slight additional strengthening in the
short term can not be ruled out, however the global models indicate
that strong wind shear will continue through the forecast period and
the flow aloft will become less supportive for convection by late
Sunday or early Monday. All of the intensity models forecast that
Xavier will begin to weaken in about 24 h. By 96 h, if not sooner,
the dynamical models indicate that Xavier will lose all deep
convection and become a remnant low. Virtually no change was made to
the official intensity forecast, which is merely an update of the
previous advisory.

Xavier is now moving toward the northeast, and the initial motion
estimate is 035/6 kt. With the continued exception of the UKMET
model, the typically reliable track guidance is in good agreement
on the track of the tropical storm. The cyclone will likely turn
northward tonight or tomorrow, and is then forecast to turn steadily
westward in another day or two as it weakens and becomes vertically
shallow. The UKMET does not show this turn and shows a
stronger/deeper Xavier that moves farther north, though this
scenario appears unlikely given the strong agreement among the
intensity models that Xavier will weaken. Only minor adjustments
were made to the NHC track forecast, which blends the previous
official forecast with the HCCA and GFEX consensus aids at most
forecast hours.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0300Z 16.1N 105.7W 50 KT 60 MPH
12H 04/1200Z 16.7N 105.6W 50 KT 60 MPH
24H 05/0000Z 17.4N 105.9W 45 KT 50 MPH
36H 05/1200Z 17.8N 106.6W 40 KT 45 MPH
48H 06/0000Z 17.9N 107.7W 35 KT 40 MPH
72H 07/0000Z 18.1N 110.1W 30 KT 35 MPH
96H 08/0000Z 18.3N 112.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 09/0000Z 18.5N 115.0W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Zelinsky
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Re: EPAC: XAVIER - Tropical Storm

#17 Postby Nancy Smar » Sun Nov 04, 2018 3:40 am

000
WTPZ45 KNHC 040838
TCDEP5

Tropical Storm Xavier Discussion Number 7
NWS National Hurricane Center Miami FL EP252018
300 AM CST Sun Nov 04 2018

Xavier remains a sheared tropical cyclone. Although deep convection
continues to develop over the northeastern portion of the
circulation, recent satellite imagery suggests that the center has
become a little more exposed to the southwest of the convective
mass. Objective and subjective Dvorak T-numbers have not changed
overnight, and a blend of those data along with the latest SATCON
estimate still yields an initial wind speed of 50 kt.

Xavier has likely peaked in intensity as the strong vertical wind
shear over the system is forecast to increase further today and
tonight. This should result in gradual weakening during the
next day or two, and the new NHC intensity forecast follows the
trend of the latest multi-model intensity consensus. The dynamical
models indicate that Xavier will lose its deep convection in 48 to
72 hours, and the official forecast calls for the system to
degenerate to a remnant low by day 3.

The latest satellite fixes suggest that Xavier has made its
anticipated northward turn. The tropical storm is forecast to
move slowly northward today, but it should turn west-northwestward,
then westward during the next 24 to 36 hours as it weakens and is
steered by the low-level flow to the south of a subtropical ridge.
The UKMET model remains an outlier as it keeps the cyclone stronger
and deeper which allows Xavier to move much farther north. The
remainder of the track guidance is in good agreement, and the
updated NHC track is near a blend of the HWRF, GFS, and ECMWF
models, and is very close to the latest FSSE guidance.

Although the center Xavier is not forecast to move much closer to
the coast of southwestern Mexico, large swells and locally heavy
rainfall could affect portions of that area during the next day or
two.

FORECAST POSITIONS AND MAX WINDS

INIT 04/0900Z 16.6N 105.9W 50 KT 60 MPH
12H 04/1800Z 17.3N 105.9W 45 KT 50 MPH
24H 05/0600Z 17.8N 106.7W 40 KT 45 MPH
36H 05/1800Z 18.0N 107.8W 35 KT 40 MPH
48H 06/0600Z 18.2N 109.0W 30 KT 35 MPH
72H 07/0600Z 18.3N 111.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 08/0600Z 18.5N 113.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 09/0600Z...DISSIPATED

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

#18 Postby TorSkk » Sun Nov 04, 2018 10:43 am

Tropical Storm Xavier Discussion Number 8
NWS National Hurricane Center Miami FL EP252018
900 AM CST Sun Nov 04 2018

Xavier surprised us a little bit this morning when most of its deep
convection was sheared away, revealing that the center of
circulation was farther northeast than previously estimated.
A 1234 UTC SSMIS microwave pass showed that the mid-level center was
moving onshore the coast of Mexico with the deep convection, but the
low-level center remains well offshore. Some new convection has
recently developed near the low-level center, as well as in a band
to the northwest. Objective and subjective Dvorak T-numbers have
begun to fall given the decrease in deep convection, and Xavier's
initial intensity is therefore lowered to 45 kt.

Various shear calculations indicate that Xavier is now being
affected by 20-25 kt of southwesterly shear, which is expected to
increase further during the next 24 hours. In addition, GOES-16
low-level water vapor imagery shows that dry air has infiltrated
Xavier's circulation. The shear and dry air should make it harder
and harder for Xavier to maintain organized deep convection, and
the cyclone is therefore forecast to steadily weaken and degenerate
into a remnant low in about 48 hours. The NHC intensity forecast
lies within the tightly packed intensity guidance envelope and is
generally an update of the previous forecast. The remnant low of
Xavier is likely to dissipate by day 5.

Xavier's surface center appears to have been tugged northeastward by
deep convection over the past 12 hours, which suggests a
longer-term motion of 020/9 kt. Now that most of the convection
has been sheared away, however, the surface center seems to have
slowed down, and the advisory motion is 005/5 kt. The track
guidance continues to insist that Xavier will turn northwestward
and west-northwestward during the next 24 hours as its circulation
becomes shallower and is steered by lower-level easterly winds.
The UKMET is the notable outlier, keeping Xavier as a deeper
circulation and moving it more northward, closer to the coast of
Mexico. The new NHC track forecast is generally between the
multi-model consensus aids (near the northern side of the guidance
envelope) and the GFS/ECMWF solutions (near the southern side), and
it lies north of the previous forecast to account for the adjusted
initial position.

Large swells, locally heavy rainfall, and gusty winds could affect
portions of the coast of southwestern Mexico during the next day or
two, even with the center forecast to remain offshore.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 17.6N 105.3W 45 KT 50 MPH
12H 05/0000Z 18.1N 105.8W 40 KT 45 MPH
24H 05/1200Z 18.5N 106.7W 35 KT 40 MPH
36H 06/0000Z 18.8N 107.8W 30 KT 35 MPH
48H 06/1200Z 19.1N 109.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 07/1200Z 19.3N 111.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 08/1200Z 19.2N 113.8W 15 KT 15 MPH...POST-TROP/REMNT LOW
120H 09/1200Z...DISSIPATED

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

#19 Postby cycloneye » Sun Nov 04, 2018 3:42 pm

BULLETIN
Tropical Storm Xavier Advisory Number 9
NWS National Hurricane Center Miami FL EP252018
300 PM CST Sun Nov 04 2018

...XAVIER MOVING SLOWLY NORTHWARD OFF THE COASTS OF COLIMA AND
JALISCO...
...HEAVY SHOWERS AND GUSTY WINDS OCCURRING ALONG PORTIONS OF THE
COAST OF SOUTHWESTERN MEXICO...


SUMMARY OF 300 PM CST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...18.1N 105.5W
ABOUT 100 MI...160 KM SW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...N OR 350 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES
--------------------------------------------------------------------


Tropical Storm Xavier Discussion Number 9
NWS National Hurricane Center Miami FL EP252018
300 PM CST Sun Nov 04 2018

After being sheared off this morning, deep convection has
redeveloped and persisted over Xavier's center of circulation.
Dvorak Current Intensity numbers from TAFB and SAB remain 3.0, and
the latest UW-CIMSS SATCON estimate is 43 kt. The initial intensity
therefore remains 45 kt. Although shear analyses indicate that
about 25 kt of southwesterly shear is affecting Xavier, an
upper-level trough in the vicinity appears to be producing a decent
amount of divergence aloft to support the ongoing convection. The
global models show that trough dissipating and the upper flow
becoming unidirectional within 12 hours, which should cut off the
divergence and allow the adverse effects of shear and dry air to
take over. As a result, gradual weakening is expected during the
next couple of days, and Xavier may cease to produce organized deep
convection (and thus become a remnant low) in 36-48 hours. The
remnant low should dissipate by day 4, if not sooner. The updated
NHC intensity forecast is conservative, following continuity from
the previous forecast and lying near the upper bound of the
intensity models.

Xavier's motion still appears to be slowly northward, or 350/5 kt.
The global models, most of which assume that Xavier will become a
shallow system soon, show the cyclone turning northwestward and
west-northwestward during the next 24 hours. While this seems
reasonable, as long as Xavier maintains vertical integrity, it will
likely continue moving closer to the right side of the guidance
envelope. With the assumption that deep convection won't dissipate
right away, the NHC track forecast is to the right of the consensus
aids, close to the ECMWF solution, during the first 24 hours.
After 24 hours, it remains close to the TVCN multi-model consensus.

A 1600 UTC ASCAT pass indicated that Xavier's tropical-storm-force
wind field on the east side was larger than previously estimated,
with those winds lying near the coast of southwestern Mexico. As a
result, the government of Mexico issued a Tropical Storm Warning for
a portion of the coasts of Michoacan, Colima, and Jalisco. Locally
heavy rainfall and large swells are also likely to affect the coast
of southwestern Mexico during the next day or two.


FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 18.1N 105.5W 45 KT 50 MPH
12H 05/0600Z 18.7N 106.0W 40 KT 45 MPH
24H 05/1800Z 19.2N 107.1W 35 KT 40 MPH
36H 06/0600Z 19.5N 108.2W 30 KT 35 MPH
48H 06/1800Z 19.6N 109.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 07/1800Z 19.4N 111.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 08/1800Z 19.0N 114.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
120H 09/1800Z...DISSIPATED

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

#20 Postby cycloneye » Mon Nov 05, 2018 5:54 am

Tropical Storm Xavier Discussion Number 11
NWS National Hurricane Center Miami FL EP252018
300 AM CST Mon Nov 05 2018

The satellite presentation of Xavier has degraded somewhat
overnight, with the main area of convection decreasing in coverage
and becoming more separated from the low-level center. Somewhat
surprisingly, a couple of ASCAT passes between 0345 and 0500 UTC
indicated peak winds of around 50 kt. This suggests that Xavier may
have been slightly stronger than previously estimated since the
overall structure of the storm was better defined yesterday
afternoon and evening. Based on these data, the intensity was
adjusted to 50 kt on the 0600 UTC intermediate advisory, and remains
at that value for now. The intensity forecast reasoning remains
unchanged. Strong shear and an increasingly drier mid-level air
mass are expected to cause the tropical storm to weaken fairly
quickly over the next day or so, and the global models suggest that
Xavier will degenerate into a remnant low in 36 to 48 hours.

Xavier has been moving slowly northwestward or 305/3 kt. A low- to
mid-level ridge that is building to the north of Xavier should
cause the cyclone to turn west-northwestward, and then westward
during the next 12 to 24 hours. As the system weakens it is
forecast to move westward or west-southwestward within the
low-level flow until dissipation occurs in 3 to 4 days. The track
guidance envelope shifted somewhat southward this cycle, and as a
result, the official forecast was adjusted in that direction but it
remains to the north of the consensus models out of respect for
continuity with the previous NHC track.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 18.4N 105.9W 50 KT 60 MPH
12H 05/1800Z 18.7N 106.8W 40 KT 45 MPH
24H 06/0600Z 18.9N 108.0W 35 KT 40 MPH
36H 06/1800Z 19.1N 109.3W 30 KT 35 MPH
48H 07/0600Z 19.2N 110.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 08/0600Z 19.0N 112.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 09/0600Z...DISSIPATED

$$
Forecaster Brown
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