EPAC: PAMELA - Remnants

[Kingarabian]

Could it still get to hurricane status? Probably. But explosive RI that the GFS has been insisting on remains doubtful. Cimss shows it surrounded by 10-20kts of mid shear.

[aspen]

Could it still get to hurricane status? Probably. But explosive RI that the GFS has been insisting on remains doubtful. Cimss shows it sorrunded by 10-20kts of mid shear.

The fact that this still doesn’t have an inner core yet will make any kind of RI even less likely with mid-level shear lurking around. Pamela might be lucky to get to 85-90 kt at this rate, which would make it more of an Olaf-like impact than a Willa-like impact.

[Yellow Evan]

Pamela seems to be at the stage where it’s suffering from dry air intrusions. I’d expected continued slow deepening for another 12 hours.

[Teban54]

This looks awful given the high expectations we had. Although that's definitely a good thing for Mexico.

[Category5Kaiju]

Pamela's struggles right now are hopefully good news in the long term for Mexico, and I can't say that I am surprised given it's a solid -ENSO year with lurking dry air and shear.

[Yellow Evan]

Convection trying to rotate upshear, but the MLC and LLC are displaced, and the LLC seems on the brink of becoming exposed. Odds of this busting are higher than they were yesterday as it’s clear that at least for now sub-outflow layer shear is disrupting it.

[aspen]

I would be concerned about an Ida-like situation where it undergoes a quick phase of ERI before landfall, but that would require a core to pull off, and the jet streak could be a double edged sword as Pamela recurves. The otherwise favorable jet streak interaction and the Patricia-level MPIs won’t mean anything if Pamela can’t even get its LLC and MLC stacked despite an environment forecast to be very favorable.

If Pamela isn’t even able to get past 70-75 kt, it’ll be one of the biggest model busts of the last few years, failing to meet the decent model agreement of a Category 4 hurricane. A hurricane landfall is still likely, but chances for a major continue to decrease the longer Pamela goes without a core. I doubt it’s even 60 kt right now.

[Sciencerocks]

[cycloneye]

Tropical Storm Pamela Discussion Number 7
NWS National Hurricane Center Miami FL EP162021
300 PM MDT Mon Oct 11 2021

Entrainment of dry mid-level air along with some modest
north-northwesterly mid-level shear has caused Pamela's low-level
circulation to become slightly exposed just northwest of the
somewhat ragged inner-core convection. Upper-level outflow, however,
has improved in all quadrants, with a narrow equatorward outflow
channel having developed in the eastern semicircle since the
previous advisory. Pamela's intensity was increased to 60 kt at
1800 UTC based on satellite current-intensity estimates of T4.0/65
kt from TAFB and T3.7/59 kt from UW-CIMSS ADT. However, 60 kt might
be a little generous at the 2100 UTC advisory time, given that the
low-level center has recently become partially exposed.

The motion estimate is northwestward or 320/06 kt. There is no
significant change to the previous forecast track or reasoning. This
current slow northwestward motion should continue this afternoon and
evening as Pamela approaches the western periphery of a deep-layer
subtropical ridge. Later tonight, the cyclone is expected to turn
slowly northward, followed by a faster northeastward motion by
Tuesday night as Pamela gets caught up in moderate southwesterly
flow ahead of a deep-layer mid-latitude trough approaching from the
northwest and west. This developing flow pattern is depicted quite
well by all of the global and regional models, and should result in
Pamela accelerating northeastward on Wednesday right up until the
storm makes landfall along the west-central coast of Mexico. The new
NHC forecast track has been shifted a little to the right again,
and is close to the middle of the tightly packed TCVE, GFEX,
NOAA-HCCA, and FSSE consensus track-model envelope.

The global and regional models are in very good agreement that the
current slight southeastward tilt to the vortex column should abate
within the next 6 hours or so, along with the dry mid-level air
mixing out. As a result, deep convection should re-fire near the
center later tonight, resulting in the development of an eyewall,
which will create the necessary chimney effect to allow Pamela to
resume its earlier rapid intensification trend. In fact, all of the
models now show strengthening right up until the cyclone makes
landfall on Wednesday due to the upper-level outflow pattern
expanding, along with the development of poleward and equatorward
outflow channels by late Tuesday. The new official intensity
forecast is basically the same as the previous advisory, and lies
near the upper-end of the intensity guidance. Pamela is still
expected to become a dangerous major hurricane prior to landfall.
After landfall occurs, rapid weakening is forecast due to the
cyclone moving over the rugged terrain of west-central Mexico.
However, the higher elevations of north-central Mexico could still
receive tropical-storm force winds after Pamela moves well inland.
Furthermore, deep moisture associated with Pamela will gradually
overspread much of north-central and northeastern Mexico late on
Wednesday, and then move into southern and central Texas on
Thursday, enhancing the rainfall potential in those areas.

An Air Force Reserve Hurricane Hunter aircraft is scheduled to
investigate Pamela on Tuesday during the late morning and early
afternoon to provide a better estimate of the cyclone's intensity.


Key Messages:

1. Pamela is forecast to be a major hurricane when it reaches the
coast of west-central mainland Mexico on Wednesday, and
life-threatening storm surge and dangerous hurricane-force winds are
possible within the Hurricane Watch area. Residents in this area
should monitor the progress of Pamela and follow any advice given by
local officials.

2. Pamela is expected to pass near or south of the southern tip of
the Baja California peninsula as a hurricane Tuesday night and early
Wednesday, and tropical-storm conditions are possible within the
Tropical storm Watch area.

3. Heavy rains associated with Pamela are expected to move into the
Mexican States of Sinaloa and western Durgano along with southern
portions of Baja California Sur Tuesday and Wednesday. This will
pose a threat of significant and life-threatening flash flooding and
mudslides.

4. Heavy rains associated with Pamela are expected across portions
of central Texas and southeastern Oklahoma late Wednesday and
Thursday. This may result in flash and urban flooding.

FORECAST POSITIONS AND MAX WINDS

INIT 11/2100Z 17.2N 108.5W 60 KT 70 MPH
12H 12/0600Z 18.3N 109.0W 70 KT 80 MPH
24H 12/1800Z 20.0N 108.9W 85 KT 100 MPH
36H 13/0600Z 22.0N 107.8W 100 KT 115 MPH
48H 13/1800Z 24.3N 105.8W 45 KT 50 MPH...INLAND
60H 14/0600Z 27.4N 102.1W 30 KT 35 MPH...POST-TROP/INLAND
72H 14/1800Z 31.2N 97.7W 20 KT 25 MPH...POST-TROP/INLAND
96H 15/1800Z...DISSIPATED INLAND

$$
Forecaster Stewart

[Teban54]

A few hot towers are firing closer to the LLC in recent frames. We'll see whether they can wrap around, but it looks like Pamela is having to start from scratch again.

[zeehag]

Pamela's struggles right now are hopefully good news in the long term for Mexico, and I can't say that I am surprised given it's a solid -ENSO year with lurking dry air and shear.

please let this be so.
as for starting from scratch she is in the area in which all of em ri, so that is a hold my beer moment for her.

[aspen]

Stewart is putting an awful lot of faith in short-term model forecasts. That won’t end well IMO.

[Ubuntwo]

Partial cyan ring though a little weak with the dry air intrusion.

[InfernoFlameCat]

I think this has absurd potential. Remember Patricia 24 hours before Cat 5?, looked worse than this IMO. Also look at the double poleward outflow developing, especially on the southern end. With that trough to the north expected to enhance that tropical moisture flow, this thing could reach sub 900 still. Will it? Very doubtful. But do not check off Pamela just yet. I feel she has an ace or two up her sleeve.

[Yellow Evan]

MLC and LLC are displaced, though there’s at least a partial eyewall at the low levels.

[Yellow Evan]

Dual rotating convection bursts, if it continues, is definitely a positive step. Banding nearly 100% wrapped around the center as well.

[aspen]

Given Pamela’s performance today and current structure, I will be very surprised if it’s anything stronger than 65-70 kt tomorrow morning. Recon might not even find a hurricane if it continues to ingest dry air and fails to build a core. I think a steady intensity with a strong TS at landfall is not impossible — the exceptionally favorable SSTs and UL environment won’t matter if Pamela doesn’t have a core. Unless Pamela undergoes a rapid recovery over the next 12-18 hours, I’d say its chances of becoming a major are very slim.

[Kingarabian]

Yeah shallow warm convection mainly. This isn't Patricia pre Cat.5 by any stretch.

[Yellow Evan]

18z GFS shows only steady deepening up to landfall now.

[galaxy401]

I have always been skeptical and unconvinced that Pamela will reach the heights of Kenna, Rick, Patricia, and Willa. The problem with these comparisons is that those hurricanes formed in El Nino years so they had a very favorable environment. Pamela is in a more borderline La Nina environment. So I have my doubts Pamela will even reach Category 4 in my opinion. I'm thinking Cat 3 at most.

Pamela could still prove me wrong though so I guess we'll see.