ATL: CLAUDETTE - Remnants - Discussion

[Steve]

At some point I was going to bring up how the NOLA area got hit with another storm named Bill back in 2003, but that may not be necessary.

Bill ‘03 was great. Center of circulation passed overhead.

[Shell Mound]

At some point I was going to bring up how the NOLA area got hit with another storm named Bill back in 2003, but that may not be necessary.

Bill ‘03 was great. Center of circulation passed overhead.

Interestingly, 2021 and 2003 share the same list of names. Of course, if 92L were to become Claudette, it would be far more mundane than 2003’s iteration.

[eastcoastFL]

Still a sloppy yet persistent blob this morning

[Sciencerocks]

[jasons2k]

Morning update from Jeff Lindner:

There has been little change in the overall organization with the broad elongated trough over the SW and S Gulf of Mexico over the last 24 hours. There continues to be no defined surface low pressure system at the surface and instead a broad trough axis extending from the coast of Mexico ESE across the Bay of Campeche. Scattered showers and thunderstorms continue to develop in the area/region, but remain disorganized.

Global models continue to insist that a surface low will slowly and eventually form in this region toward the next or end of this week. Little motion is expected over the next 48-72 hours as steering currents remain weak, but a northward motion at an increasing forward speed is expected by Friday into the weekend. It will be important where the actual center forms in the southern Gulf of Mexico later this week as to the eventual final track of 92L along with the position and intensity of high pressure ridges over the SW US and off the SE US coast and a departing trough over the US east coast. There is likely to be some degree of WSW/SW upper level wind shear over the western Gulf of Mexico as 92L begins to lift northward along with a large mass of dry air over TX that may become ingested into the circulation of the system. This points toward 92L having the majority of its associated moisture well to the east of any actual surface center and increases the potential for center re-locations toward the deeper convective masses on the eastern flank of the system.

In following with the increasingly consistency of the global model guidance and the general steering pattern later this week, a northward motion is expected toward the NW or NC Gulf coast. At this time is appears the majority of the weather and impacts associated with 92L will be east of SE TX, but due to the uncertainty on where the exact center forms there remains some degree of uncertainty on the local impacts and as always when dealing with any sort of tropical system, pay attention to forecasts daily for any changes.

The NHC currently gives 92L a 60% chance of tropical cyclone formation over the next 5 days.

Elsewhere:
A brief tropical system may attempt to develop off the US east coast over the next 12-24 hours as satellite and radar images show a well defined circulation surrounded by showers and thunderstorms. Any development will likely be short lived and move generally away from the US east coast.

A tropical wave will exit Africa and while the wave looks impressive on satellite images, development is unlikely due to still cold June water temperatures.

[Steve]

At some point I was going to bring up how the NOLA area got hit with another storm named Bill back in 2003, but that may not be necessary.

Bill ‘03 was great. Center of circulation passed overhead.

Interestingly, 2021 and 2003 share the same list of names. Of course, if 92L were to become Claudette, it would be far more mundane than 2003’s iteration.

Yeah no doubt Shell. Claudette was one of those tighten up near TX landfall storms. I think it was the first one to hit Port O'Connor area since a couple decades before that. 92L looks to be a North mover (maybe NNE) with the rain north and east of the center. If it comes in somewhere between Galveston and Morgan CIty (which it looks like Cameron/Vermilion Parishes from this far out), some people will flood east of there. I'd put the likelihood of flooding rainfall potential anywhere from east of where the circulation comes in over to about Santa Rosa County, Florida.

[Jr0d]

Not looking at all today. If it was not for the model support, I would not give it much chance of doing anything. However, it was not expected to do much until mid week.

[galaxy401]

20/70 now.

1. Showers and thunderstorms continue over the Bay of Campeche in
association with a broad low pressure area. Gradual development of
this disturbance is possible during the next couple of days while it
meanders near the coast of Mexico. The system should begin to move
northward by midweek, and a tropical depression is likely to form
late in the week when the low moves across the central or
northwestern Gulf of Mexico. Regardless of development, heavy
rainfall is possible over portions of Central America and southern
Mexico during the next several days. Heavy rains could also begin
to impact portions of the northern Gulf Coast on Friday. Please
consult products from your local meteorological service for more
information.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...high...70 percent.

[eastcoastFL]

Is there any chance the center ends up being pulled further East where most of the convection is?





I know at least one model showed development coming from the area of persistent convection off of the Yucatán

[USTropics]

Is there any chance the center ends up being pulled further East where most of the convection is?

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/gm/GEOCOLOR/20211651841_GOES16-ABI-gm-GEOCOLOR-1000x1000.jpg

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/gm/Sandwich/20211651836_GOES16-ABI-gm-Sandwich-1000x1000.jpg

I know at least one model showed development coming from the area of persistent convection off of the Yucatán

Yes, that's still a possibility as well. We will likely see multiple, embedded areas of vorticity maxima within the larger gyre circulation over the coming days with this system. The 12z GFS 850mb forecast is a great illustration of this:



In fact, looking at the synoptic setup, a center establishing more towards the NE is as realistic a scenario as a center remaining towards the south when analyzing RH and shear forecasts. Dry, continental air will be established on the western side of the gyre as the high pressure over the SW United States flattens out in the next 3-5 days, and any vorticity that tries to establish itself could entrain some of this dry air. This isn't as much of an issue on the eastern side of the gyre:



The issue with a low-level center forming towards the NE is the shear axis. However, if there isn't a dominant low-level vort max already established to the south, it's not uncommon for an LLC to follow lowering pressures, which would be towards the NE. The curvature of the shear axis could also help "spin up" a low-level circulation in this area as well; it's a tricky dance of getting too close to the fire but not getting burned.



Regardless of the outcome, a sheared and east weighted system is expected. This will likely be a system where the mid-level and lower-level circulations never become fully stacked (check out the 12z ECMWF forecast, where land interaction actually assists in tightening up the vort maxima at the lower levels).

[AnnularCane]

If that Euro run actually happens, I may have to think about evacuating. If it just went a little further north...

[Sciencerocks]

[tailgater]

If that Euro run actually happens, I may have to think about evacuating. If it just went a little further north...

Well if you can believe the new crazy uncle the “navgem” you might want to start mapping a route:)

[AnnularCane]

If that Euro run actually happens, I may have to think about evacuating. If it just went a little further north...

Well if you can believe the new crazy uncle the “navgem” you might want to start mapping a route:)

Well, it doesn't look too strong, so I might take my chances for now.

[cycloneye]

Disorganized showers and thunderstorms continue over the Bay of
Campeche in association with a broad low pressure area. Gradual
development of this disturbance is possible during the next couple
of days while it meanders near the coast of Mexico. The system
should begin to move northward by midweek, and a tropical depression
is likely to form late in the week when the low moves across the
central or northwestern Gulf of Mexico. Regardless of development,
heavy rainfall is possible over portions of Central America and
southern Mexico during the next several days. Heavy rains could
also begin to impact portions of the northern Gulf Coast on Friday.
Please consult products from your local meteorological service for
more information.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...high...70 percent.

[cycloneye]

AL, 92, 2021061500, , BEST, 0, 199N, 944W, 20, 1009, LO

[eastcoastFL]

Is there any chance the center ends up being pulled further East where most of the convection is?

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/gm/GEOCOLOR/20211651841_GOES16-ABI-gm-GEOCOLOR-1000x1000.jpg

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/gm/Sandwich/20211651836_GOES16-ABI-gm-Sandwich-1000x1000.jpg

I know at least one model showed development coming from the area of persistent convection off of the Yucatán

Yes, that's still a possibility as well. We will likely see multiple, embedded areas of vorticity maxima within the larger gyre circulation over the coming days with this system. The 12z GFS 850mb forecast is a great illustration of this:

https://s6.gifyu.com/images/68d29d82-6390-4cb0-8e87-052c03ccee58.gif

In fact, looking at the synoptic setup, a center establishing more towards the NE is as realistic a scenario as a center remaining towards the south when analyzing RH and shear forecasts. Dry, continental air will be established on the western side of the gyre as the high pressure over the SW United States flattens out in the next 3-5 days, and any vorticity that tries to establish itself could entrain some of this dry air. This isn't as much of an issue on the eastern side of the gyre:

https://i.imgur.com/MwrEmcx.png

The issue with a low-level center forming towards the NE is the shear axis. However, if there isn't a dominant low-level vort max already established to the south, it's not uncommon for an LLC to follow lowering pressures, which would be towards the NE. The curvature of the shear axis could also help "spin up" a low-level circulation in this area as well; it's a tricky dance of getting too close to the fire but not getting burned.

https://i.imgur.com/EuUJ1KM.png

Regardless of the outcome, a sheared and east weighted system is expected. This will likely be a system where the mid-level and lower-level circulations never become fully stacked (check out the 12z ECMWF forecast, where land interaction actually assists in tightening up the vort maxima at the lower levels).
https://s6.gifyu.com/images/ecmwf_uv850_vort_atl_fh0-192.gif

I saw that GFS run and it does look plausible. Especially now where it appears most of the convection is overland already. Is it my eyes or does it look like the storm deepens after moving over land and north of Louisiana on the models?

[eastcoastFL]

Majority of the convection is now overland to the south of the circulation.

[AnnularCane]

Guess this one won't be Bill.

[tailgater]

Low level structure looked much improved before sunset, d-max will likely light up the BOC in the morning. Just my uneducated weather observer opinion.