ATL: ERIN - Tropical Depression - Discussion

[wxman57]

My first attempt at a track. Had to completely ignore the GFS, as it kept a low center in the Gulf for quite a while. Closer to the ECMWF for now. Will take a look at the 12Z model runs and update the track accordingly.

http://wxman57.com/images/98LTrack.JPG

im preparing for a landfalling wxman 57 system

Board up your windows IMMEDIATELY! You could see winds of 5-15 mph.

[GCANE]

3500 CAPE pretty much over half the state of Florida south to the Keys.
LI at -7
No convection inhibition with good mid-level lapse rate.
Should see convection fire off over the lower part of the state in the afternoon.
Will feed a lot of moisture into 98L.

[GCANE]

UL Trough is digging in more.
Enhancing convection outflow.

[GCANE]

If we see a big blow up in convection over the state, a good chunk of the UL Trough could likely get taken out.
Already looks like a cell is firing on the west end of Lake O

[Aric Dunn]

Sustained convection on east side of the center. Considering it was devoid of convection near the center its life time thus far. this is a sign convergence is increasing.

[Aric Dunn]

up to 70.. not surprised.. but still conservative.

[cycloneye]

Surface and radar data, along with satellite imagery, indicate that
the low pressure area just east of the coast of southeastern Florida
is becoming better organized. The low is forecast to move generally
northwestward near or over the eastern Florida peninsula through
tonight, and then move northward to northeastward over the Atlantic
near the east coast of the central Florida peninsula on Saturday.
After that, the system is expected to move northeastward offshore of
the southeastern United States coast. If the current trend
continues, a tropical depression is likely to form by Saturday
night. Regardless of development, locally heavy rains are possible
over the northwestern Bahamas and the southern and central Florida
peninsula through the weekend. Interests in the northwestern
Bahamas, the Florida peninsula, and the southeast coast of the
United States should monitor the progress of this system. An Air
Force Reserve Hurricane Hunter aircraft is scheduled to investigate
the system on Saturday, if necessary.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

[AnnularCane]

What time is recon? Is that still scheduled?

[jlauderdal]

My first attempt at a track. Had to completely ignore the GFS, as it kept a low center in the Gulf for quite a while. Closer to the ECMWF for now. Will take a look at the 12Z model runs and update the track accordingly.

http://wxman57.com/images/98LTrack.JPG

im preparing for a landfalling wxman 57 system

Board up your windows IMMEDIATELY! You could see winds of 5-15 mph.

my hurricane kit is ready, low pressure lurking offshore, ready to strike. had a shower an hour ago, full sun right now

[Hammy]

This is coming together much quicker than I expected.

[Emmett_Brown]

My first attempt at a track. Had to completely ignore the GFS, as it kept a low center in the Gulf for quite a while. Closer to the ECMWF for now. Will take a look at the 12Z model runs and update the track accordingly.

http://wxman57.com/images/98LTrack.JPG

Nice, thanks for posting this . It would be cool if you could post these for future systems as well

[GCANE]

What time is recon? Is that still scheduled?

Should be in the air any minute

My Bad - its tomorrow 18Z

[Aric Dunn]

Looks like a very wet track from the euro again.. but I guess we should forget the models.

[tolakram]

up to 70.. not surprised.. but still conservative.

Polite pushback Aric.

Tropical Disturbance
A discrete tropical weather system of apparently organized convection - generally 200 to 600 km (100 to 300 nmi) in diameter - originating in the tropics or subtropics, having a nonfrontal migratory character, and maintaining its identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field. Disturbances associated with perturbations in the wind field and progressing through the tropics from east to west are also known as easterly waves .

Tropical Depression
A tropical cyclone in which the maximum sustained wind speed (using the U.S. 1 minute average standard) is up to 33 kt (38 mph, 17 m/s). Depressions have a closed circulation.

source: https://www.aoml.noaa.gov/hrd/tcfaq/A5.html

Has anyone observed a 33 kt 1 minute average wind? I know it's a guess without recon or direct observations but since convection has only just formed near the center I think another 12 hours before designation is warranted, unless it's projected to hit land as a stronger storm.

[Aric Dunn]

up to 70.. not surprised.. but still conservative.

Polite pushback Aric.

Tropical Disturbance
A discrete tropical weather system of apparently organized convection - generally 200 to 600 km (100 to 300 nmi) in diameter - originating in the tropics or subtropics, having a nonfrontal migratory character, and maintaining its identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field. Disturbances associated with perturbations in the wind field and progressing through the tropics from east to west are also known as easterly waves .

Tropical Depression
A tropical cyclone in which the maximum sustained wind speed (using the U.S. 1 minute average standard) is up to 33 kt (38 mph, 17 m/s). Depressions have a closed circulation.

source: https://www.aoml.noaa.gov/hrd/tcfaq/A5.html

Has anyone observed a 33 kt 1 minute average wind? I know it's a guess without recon or direct observations but since convection has only just formed near the center I think another 12 hours before designation is warranted, unless it's projected to hit land as a stronger storm.

up to 33kts... do you take that as at least 33kts or anything up to 33kts.. but not above because that would be a TS?

This of course is important since we have had countless TD's with 20 to 25 kts winds.. soo what shall we stick with ?

[tolakram]

up to 70.. not surprised.. but still conservative.

Polite pushback Aric.

Tropical Disturbance
A discrete tropical weather system of apparently organized convection - generally 200 to 600 km (100 to 300 nmi) in diameter - originating in the tropics or subtropics, having a nonfrontal migratory character, and maintaining its identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field. Disturbances associated with perturbations in the wind field and progressing through the tropics from east to west are also known as easterly waves .

Tropical Depression
A tropical cyclone in which the maximum sustained wind speed (using the U.S. 1 minute average standard) is up to 33 kt (38 mph, 17 m/s). Depressions have a closed circulation.

source: https://www.aoml.noaa.gov/hrd/tcfaq/A5.html

Has anyone observed a 33 kt 1 minute average wind? I know it's a guess without recon or direct observations but since convection has only just formed near the center I think another 12 hours before designation is warranted, unless it's projected to hit land as a stronger storm.

up to 33kts... do you take that as at least 33kts or anything up to 33kts.. but not above because that would be a TS?

Yea, I screwed that up. TD is a very loose designation, without any hard scientific point to call it a TD. We only know the point above which it is a TS if there is a closed circulation.

[Hypercane_Kyle]

Should be TD4 by as early as Saturday night IMO.

[wxman57]

Circulation looks less well-defined than a few hours ago. I can't find evidence of an LLC in the latest surface obs as I could this morning. It may be moving ashore north of Miami.

[Aric Dunn]

Polite pushback Aric.

Tropical Disturbance
A discrete tropical weather system of apparently organized convection - generally 200 to 600 km (100 to 300 nmi) in diameter - originating in the tropics or subtropics, having a nonfrontal migratory character, and maintaining its identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field. Disturbances associated with perturbations in the wind field and progressing through the tropics from east to west are also known as easterly waves .

Tropical Depression
A tropical cyclone in which the maximum sustained wind speed (using the U.S. 1 minute average standard) is up to 33 kt (38 mph, 17 m/s). Depressions have a closed circulation.

source: https://www.aoml.noaa.gov/hrd/tcfaq/A5.html

Has anyone observed a 33 kt 1 minute average wind? I know it's a guess without recon or direct observations but since convection has only just formed near the center I think another 12 hours before designation is warranted, unless it's projected to hit land as a stronger storm.

up to 33kts... do you take that as at least 33kts or anything up to 33kts.. but not above because that would be a TS?

Yea, I screwed that up. TD is a very loose designation, without any hard scientific point to call it a TD. We only know the point above which it is a TS if there is a closed circulation.

yeah no worries

anyway... typically when a closed well defined circ is there and sustained convection and percentages being 50 or above they typically upgrade. given the potential for overall deepening.

thats the point I suppose. the ambiguity the last couple years has been back and forth.. so per any definition, this is a warm core TC. Hence and TD.

not bashing the NHC or anything. I stick with trying to be consistent is all.

[northjaxpro]

This is coming together much quicker than I expected.

Me too!! I thought it would struggle initially to get going
But it really has pulled together today rather nicely 98L.