EPAC: PILAR - Post-Tropical - Discussion

[cycloneye]

South of Central America and Mexico (EP92):
A broad area of low pressure located a couple of hundred miles
south-southwest of the southern coast of El Salvador is continuing
to produce disorganized shower and thunderstorm activity.
Environmental conditions appear to be conducive for development of
this system, and a tropical depression is likely to form by this
weekend while the low moves slowly northwestward to northward.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

[Sciencerocks]

[cycloneye]

Looks good.

 https://twitter.com/CIRA_CSU/status/1718002376932778073

[cycloneye]

South of Central America and Mexico (EP92):
A broad area of low pressure is located a couple of hundred miles
south of the coast of Guatemala. Most of the shower and thunderstorm
activity in the vicinity of the low appears to be located well to
the west of its broad surface center. Environmental conditions are
expected to be conducive for development during the next few days,
and a tropical depression is likely to form this weekend or early
next week. Regardless of development, the low is forecast to meander
over the far eastern portion of the Eastern Pacific basin for the
next several days.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

[cycloneye]

South of Central America and Mexico (EP92):
A broad area of low pressure located a couple of hundred miles south
of the coast of Guatemala is producing disorganized shower and
thunderstorm activity. Environmental conditions are expected to be
conducive for development during the next few days, and a tropical
depression is likely early next week. Regardless of development,
the low is forecast to meander over the far eastern portion of the
basin for the next several days. For additional information,
including gale warnings, see High Seas Forecasts issued by the
National Weather Service.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

[cycloneye]

South of Central America and Mexico (EP92):
Satellite imagery indicates that the surface circulation of a
low pressure area located a couple of hundred miles south-southwest
of the coast of Guatemala has become better defined since yesterday.
Environmental conditions are expected to be conducive for further
development, and a tropical depression is very likely to form within
the next day or two. The low is forecast to meander over the far
eastern portion of the basin for the next several days. For
additional information, including gale warnings, see High Seas
Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[Sciencerocks]

[cycloneye]

Tropical Depression Nineteen-E Discussion Number 1
NWS National Hurricane Center Miami FL EP192023
400 PM CDT Sat Oct 28 2023

The very busy October in the eastern Pacific continues this
afternoon. Satellite images indicate that Invest 92E has re-formed
a large central dense overcast near the center with curved banding
features. Unlike yesterday, however, the low-level circulation has
become better defined, as indicated by ASCAT-B scatterometer
ambiguities from 1520Z, with a small closed low shown. With Dvorak
estimates of T2.0 from TAFB, this is indicative of organized deep
convection, and thus this system has become a tropical depression.
The initial wind speed is set to 30 kt, in accordance with the non
rain-inflated scatterometer max winds of about that value.

There's been little net motion with this system during the last day
or so, and none is really expected during the next day or so with
light steering currents. A mid- to upper-level trough over the
northwestern Caribbean early next week is expected to draw the
depression northeastward towards Central America. The big question
is how close the system gets to land before ridging rebuilds after
the trough departs the region. Most of the global models move the
system quite close to Guatemala or El Salvador before being shunted
west-southwestward away from land, so this will be the official
forecast. This is a very uncertain forecast as only a one or two kt
speed difference during the next few days will have large
ramifications for any landfall chances.

The depression should be over warm waters in light or moderate shear
for the next few days. Most of the guidance show at least gradual
intensification in this pattern for 2-3 days, and the NHC intensity
forecast follows that trend, on the high side of the guidance
envelope. Around 72 h and beyond, a mix of land interaction and a
sharp increase in shear should cause weakening, and this is shown
below.


FORECAST POSITIONS AND MAX WINDS

INIT 28/2100Z 10.5N 92.7W 30 KT 35 MPH
12H 29/0600Z 10.7N 92.8W 35 KT 40 MPH
24H 29/1800Z 10.9N 92.8W 40 KT 45 MPH
36H 30/0600Z 11.1N 92.4W 45 KT 50 MPH
48H 30/1800Z 11.6N 91.4W 50 KT 60 MPH
60H 31/0600Z 12.3N 90.3W 60 KT 70 MPH
72H 31/1800Z 13.0N 89.5W 55 KT 65 MPH
96H 01/1800Z 11.3N 90.6W 40 KT 45 MPH
120H 02/1800Z 9.5N 94.0W 35 KT 40 MPH

$$
Forecaster Blake

[DorkyMcDorkface]

What a cone...

[cycloneye]

And then there is this from GFS.

[Sciencerocks]

[cycloneye]

Tropical Depression Nineteen-E Discussion Number 2
NWS National Hurricane Center Miami FL EP192023
1000 PM CDT Sat Oct 28 2023

The organization of the depression has not improved this evening.
The shower and thunderstorm activity has diminished and is mostly
confined to the northern and western portions of the circulation.
Recent satellite-derived wind data and microwave images suggest the
depression has not moved much since earlier today. Based on the
earlier scatterometer data, current structure, and a T2.0 subjective
Dvorak estimate from TAFB, the initial intensity is held at 30 kt.

The depression is currently within weak steering currents, and
little net motion is expected through Sunday while the system
meanders offshore of Central America. By early next week, the flow
associated with a mid- to upper-level trough over the northwestern
Caribbean Sea should steer the system generally northeastward
towards Central America. While the track models agree in principle
on this scenario, it remains unclear how close the cyclone will get
to the coast in 60-72 h and whether or not it will move inland.
Given this uncertainty, interests in Guatemala and El Salvador
should closely monitor the latest forecast updates, as only small
track changes could result in greater land impacts. By the middle of
next week, the flow behind a cold frontal passage to the north
should push the cyclone southwestward and away from land. The
updated NHC track forecast lies between the previous prediction and
the latest multi-model consensus aids.

Given the current structure of the depression, only modest
strengthening is forecast in the near term. Once the system becomes
better organized, the 28-29 deg C waters and abundant mid-level
moisture should allow for more intensification in 24-48 h within a
weak to moderate shear environment. This is shown by most of the
intensity models, and the NHC forecast remains on the higher end of
the guidance envelope, closest to the GFS and HFIP corrected
consensus (HCCA). Later in the period, increasing deep-layer shear
and potential land interaction should result in some weakening,
although this portion of the forecast is more dependent on the
future track of the system.


FORECAST POSITIONS AND MAX WINDS

INIT 29/0300Z 10.6N 92.8W 30 KT 35 MPH
12H 29/1200Z 10.8N 92.7W 35 KT 40 MPH
24H 30/0000Z 11.2N 92.5W 45 KT 50 MPH
36H 30/1200Z 11.5N 92.0W 50 KT 60 MPH
48H 31/0000Z 12.1N 91.0W 60 KT 70 MPH
60H 31/1200Z 12.8N 90.1W 60 KT 70 MPH
72H 01/0000Z 12.9N 89.4W 55 KT 65 MPH
96H 02/0000Z 10.5N 91.5W 40 KT 45 MPH
120H 03/0000Z 9.0N 95.0W 35 KT 40 MPH

$$
Forecaster Reinhart

[CrazyC83]

After Otis, I wonder if there will be some caution placed by NHC with this, especially in future advisories, such as predicting higher than expected intensities and an actual landfall in Central America.

[cycloneye]

Tropical Depression Nineteen-E Discussion Number 3
NWS National Hurricane Center Miami FL EP192023
400 AM CDT Sun Oct 29 2023

The depression is not well organized this morning. The circulation
appears elongated east-west and deep convection is patchy and
lacking banding features. The Dvorak T-numbers are lower than they
were yesterday, but still generally support an initial intensity of
30 kt.

The system has been wobbling around since it developed yesterday,
but over the past 6 to 12 hours it has been generally moving slowly
north-northwestward, The models agree that the depression should
begin to move northeastward at a slow pace later today. The
northeastward motion should continue through Tuesday, taking the
system very near the coasts of El Salvador and Guatemala. After
that time, a strong cold front is expected to move across Mexico and
the Gulf of Mexico, and that should cause the cyclone to reverse its
course and head southwestward away from land. The NHC track
forecast is a little slower than the previous one and roughly
between the HCCA and TVCE consensus aids. It should be noted that
confidence in the details of the track forecast is low since the
forward speed of the cyclone and timing of the cold front will make
the difference in whether or not the system moves inland over
Central America or remains offshore.

Given the broad nature of the system currently, only slow
strengthening seems likely today. However, more steady
intensification is possible tonight through Tuesday while the
system remains over very warm SSTs and in favorable atmospheric
conditions. The cyclone will likely be near hurricane
strength when it is close to the coast of Guatemala and El
Salvador on Tuesday. After that, strong vertical wind shear,
possible land interaction, and intrusions of dry air and stable air
should end the opportunity for strengthening and promote a
weakening trend. Only small changes were made to the previous NHC
intensity forecast, and this one lies near the middle of the
guidance envelope.


Key Messages:

1. Heavy rains from the tropical depression will produce flash and
urban flooding, along with mudslides in areas of higher terrain
along the Pacific coast of Central America, including El Salvador,
through Wednesday.

2. The depression is expected to strengthen as it approaches
Guatemala and El Salvador, and tropical storm or hurricane watches
could be required for portions of those areas later today.

FORECAST POSITIONS AND MAX WINDS

INIT 29/0900Z 11.0N 93.1W 30 KT 35 MPH
12H 29/1800Z 11.3N 93.0W 35 KT 40 MPH
24H 30/0600Z 11.6N 92.7W 45 KT 50 MPH
36H 30/1800Z 11.9N 91.9W 55 KT 65 MPH
48H 31/0600Z 12.4N 91.1W 60 KT 70 MPH
60H 31/1800Z 12.7N 90.2W 60 KT 70 MPH
72H 01/0600Z 12.3N 90.3W 50 KT 60 MPH
96H 02/0600Z 11.0N 92.6W 40 KT 45 MPH
120H 03/0600Z 9.3N 96.9W 35 KT 40 MPH

$$
Forecaster Cangialosi

[Sciencerocks]

[cycloneye]

Tropical Depression Nineteen-E Discussion Number 4
NWS National Hurricane Center Miami FL EP192023
1000 AM CDT Sun Oct 29 2023

The depression is becoming a bit better organized this morning,
with a curved band seeming to wrap around the apparent center.
While overnight satellite showed multiple low-level swirls within
the large circulation envelope, it seems like the system is
consolidating now near a large burst of convection. Satellite
estimates still support an initial intensity of about 30 kt for this
advisory.

There hasn't been a lot of net movement with the system, with
perhaps a slight north-northeastward motion recently. The system
should begin to move northeastward or east-northeastward at a slow
pace later today as it becomes more steered by the flow associated
with a mid- to upper-level trough over the northwestern Caribbean.
This pattern will likely take the system near the coasts of El
Salvador or Guatemala later on Tuesday. There has been a slight
southeastward trend in the model guidance, and the NHC forecast is
nudged in that direction. After that time, the synoptic pattern is
unchanged with a strong cold front expected to move across Mexico
and the Gulf of Mexico, forcing the cyclone to reverse its course
and head southwestward away from land. The NHC track forecast is
again a little slower than the previous one at long range.
Confidence in the details of the track forecast remains low since
the forward speed of the cyclone and timing of the cold front will
make the difference in whether or not the system moves inland over
Central America or remains offshore.

If the low-level center can continue consolidating, then some
slow strengthening should begin later today. More significant
intensification is possible Monday assuming a central core can
develop, with almost all guidance showing the system near hurricane
strength on Tuesday. After that, strong vertical wind shear,
possible land interaction, and intrusions of dry air and stable air
will likely cause a weakening trend. Very little change was made
to the intensity forecast, which remains near the
corrected-consensus aids.

Key Messages:

1. Heavy rains from the tropical depression will produce flash and
urban flooding, along with mudslides in areas of higher terrain
along the Pacific coast of Central America, including El Salvador,
through Wednesday.

2. The depression is expected to strengthen as it approaches
Guatemala and El Salvador, and tropical storm or hurricane watches
could be required for portions of those areas later today.


FORECAST POSITIONS AND MAX WINDS

INIT 29/1500Z 11.0N 92.8W 30 KT 35 MPH
12H 30/0000Z 11.2N 92.6W 35 KT 40 MPH
24H 30/1200Z 11.6N 92.0W 45 KT 50 MPH
36H 31/0000Z 11.9N 91.1W 55 KT 65 MPH
48H 31/1200Z 12.2N 90.2W 60 KT 70 MPH
60H 01/0000Z 12.4N 89.6W 60 KT 70 MPH
72H 01/1200Z 11.8N 89.7W 50 KT 60 MPH
96H 02/1200Z 10.7N 92.5W 40 KT 45 MPH
120H 03/1200Z 9.5N 97.5W 40 KT 45 MPH

$$
Forecaster Blake

[cycloneye]

Looking much better. It may be named Pilar later today or tonight.

[Sciencerocks]

[cycloneye]

Tropical Depression Nineteen-E Discussion Number 5
NWS National Hurricane Center Miami FL EP192023
400 PM CDT Sun Oct 29 2023

Deep convection has been increasing near the center of the
depression during the past several hours, mostly on the northwestern
side of the circulation. A scatterometer pass at 1600 UTC, however,
showed only 25-30 kt winds a fair distance northeast of the center.
With the subjective Dvorak estimates also 30 kt or less, the initial
wind speed will stay 30 kt on this advisory.

The scatterometer data suggested that the center was a bit southeast
of previous estimates, with only a northeastward drift noted during
the past 24 hours. The depression should begin to move more
steadily northeastward or east-northeastward by early Monday due to
steering flow associated with a mid- to upper-level trough over the
northwestern Caribbean. This pattern will likely take the system
near the coast of El Salvador late on Tuesday, close enough
to warrant a Tropical Storm Watch, though most of the guidance
keeps the system offshore. The NHC forecast is shifted southeast of
the previous one, similar to the guidance trend. A strong cold front
is expected to push the system west-southwestward away from Central
America by late Wednesday. Confidence in the details of the track
forecast remains low since the model guidance has been inconsistent
with the track of the system, as well as the dependence on the
incoming cold front.

Gradual intensification is forecast during the next couple of days
with the system moving over warm waters in light or moderate shear.
Increasingly southeasterly shear is noted in all of the global
models on Tuesday, so the NHC forecast will level off then, but is
still close to hurricane strength. The latest guidance has come
down a bit, though since the corrected-consensus guidance is
unchanged, the NHC forecast is about the same as the previous one.
At long range, strong vertical wind shear and intrusions of dry and
stable air will likely cause a weakening trend.


Key Messages:

1. Heavy rains from the tropical depression will produce flash and
urban flooding, along with mudslides in areas of higher terrain
along the Pacific coast of Central America, including El Salvador,
through Wednesday.

2. Tropical storm conditions are possible by early Tuesday into
Wednesday along portions of the coast of El Salvador where a
Tropical Storm Watch is now in effect. Interests elsewhere along
the Pacific coast of Guatemala, Honduras, and Nicaragua should
monitor the progress of this system as additional watches or
warnings could be needed tonight or tomorrow.

3. Swells generated by the depression will begin to affect portions
of the Pacific coast of Central America, including El Salvador,
beginning on Monday. These swells are likely to cause
life-threatening surf and rip current conditions.


FORECAST POSITIONS AND MAX WINDS

INIT 29/2100Z 10.8N 92.5W 30 KT 35 MPH
12H 30/0600Z 10.9N 92.1W 40 KT 45 MPH
24H 30/1800Z 11.2N 91.1W 50 KT 60 MPH
36H 31/0600Z 11.7N 90.1W 60 KT 70 MPH
48H 31/1800Z 12.0N 89.3W 60 KT 70 MPH
60H 01/0600Z 12.0N 89.0W 50 KT 60 MPH
72H 01/1800Z 11.4N 89.7W 45 KT 50 MPH
96H 02/1800Z 10.0N 93.0W 40 KT 45 MPH
120H 03/1800Z 9.0N 97.5W 40 KT 45 MPH

$$
Forecaster Blake

[DorkyMcDorkface]

Looks like it'll be upgraded to Pilar @ 03z:

EP, 19, 2023103000, , BEST, 0, 109N, 923W, 35, 1003, TS