ATL: ETA - Post-Tropical - Discussion

[Laser30033003]

In the latest radar loop appears the center has been trending more NNE as opposed to earlier easterly motion.

Yes looks that way to me too....

[EquusStorm]

Yeah not sure why they spent so much time on a clearly dead/dying LLC, which will die soon and is irrelevant, and missed the much more important developing circulation to the east that should rapidly take the lead, but this storm won't go down as one that's had a perfect A+ reconnaissance reliability record regardless lmao

Eta clearly not keen on behaving either way

[Aric Dunn]

In the latest radar loop appears the center has been trending more NNE as opposed to earlier easterly motion.

Yes looks that way to me too....

Probably will do a small orginizational cyclonic loop as the old llc completely dies.

[SouthDadeFish]

I see so doppler on board they use but not ground based during landfall. and nothing will beat direct measurements. radar estimate afterall.

I'm not sure what you mean by this. I've seen many references to 88D ground radar velocities in forecast discussions.

not going to get into it..

but maybe a dumb question.. if onboard radar was accurate enough why continously do passes through obviously decaying llc and not once go through the more important looking developing llc.

why do a pass at all... just fly in circles on the outer edge and use radar..

This is a very fair question. A few comments:

1) The tail Doppler radar (TDR) is an X-band radar which suffers from some attenuation issues. Can really only get reliable data out to ~50 km away from the aircraft.

2) In-situ data is still very valuable. There is some base level of uncertainty with the radar obs.

3) At the time they flew, the decaying LLC was still the location of the minimum SLP and surface circulation center technically. This is what NHC is interested in.

4) I also wish they would have directly flew threw the MLC, but there could have been safety concerns about doing so. Not sure why they didn't. Often times they try to follow a pre-set flight plan that was made well before the obs showed the center was reforming.

I hope this helps. Thanks for asking questions! I don't want to dismiss your insight, Aric, but I also want to point out the NHC is very good at what they do and many times recon has constraints/issues we don't know about.

[EquusStorm]

That old LLC seriously died super fast though, didn't take long at all. Relocation definitely looks like it's on the menu if shear stays weak enough to not keep tilting it

[Aric Dunn]

I'm not sure what you mean by this. I've seen many references to 88D ground radar velocities in forecast discussions.

not going to get into it..

but maybe a dumb question.. if onboard radar was accurate enough why continously do passes through obviously decaying llc and not once go through the more important looking developing llc.

why do a pass at all... just fly in circles on the outer edge and use radar..

This is a very fair question. A few comments:

1) The tail Doppler radar (TDR) is an X-band radar which suffers from some attenuation issues. Can really only get reliable data out to ~50 km away from the aircraft.

2) In-situ data is still very valuable. There is some base level of uncertainty with the radar obs.

3) At the time they flew, the decaying LLC was still the location of the minimum SLP and surface circulation center technically. This is what NHC is interested in.

4) I also wish they would have directly flew threw the MLC, but there could have been safety concerns about doing so. Not sure why they didn't. Often times they try to follow a pre-set flight plan that was made well before the obs showed the center was reforming.

I hope this helps. Thanks for asking questions! I don't want to dismiss your insight, Aric, but I also want to point out the NHC is very good at what they do and many times recon has constraints/issues we don't know about.

The tails doppler I knew has always had issues.

your point 3 was sort of only valid after the first, maybe second pass when the wind field begin to decay and the pressure rise. After which, I agree with your point 4. the attention should have shifted to the MLC/LLC.

From recon's little round-about you could see that pressures were similar in areas near the MLC compared to the old LLC which means there was and is likely a growing LLC there as well.

we all know you can a small localized vort max develop within the overall circ. but without direct measurement you will be at a loss.


00z models could have really benifted from them finding even a small closed vort max that had just reached the surface. but 00z models will initialize with the decaying old vort.

[Cflstorm]

I need help understanding what is happening and please correct me if I get this wrong. The old LLC is or has died off but NHC is using the old LLC location to base their latest advisory. So, if the convection is racing off towards SW Fl and a new LLC forms within it, will NHC Immed. move their track to it or gradually shift the track? To my uneducated eye, it looks like it is beelining to the Naples area. Thanks in advance!

[AutoPenalti]

The dying LLC may have been a mirage for the developing LLC underneath the convection.

[ElectricStorm]

Uhh what is going on here lol... Mission 12 into Hola


Aloha Hola

[sponger]

It is safe to say precipitation has increased dramatically.

https://www.accuweather.com/en/us/fort- ... dar/328160

[Sanibel]

Sanibel's got the perch on Eta...

Steady laminar east wind...Hardy anything...

Muggy humid...

[ElectricStorm]

...ETA'S RAIN BANDS MOVING OVER THE LOWER FLORIDA KEYS AND
APPROACHING SOUTHWESTERN FLORIDA...


SUMMARY OF 100 AM EST...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...24.4N 84.4W
ABOUT 120 MI...190 KM W OF THE DRY TORTUGAS
ABOUT 270 MI...435 KM SSW OF TAMPA FLORIDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...992 MB...29.30 INCHES

[Jr0d]

Sustained 32 kts with a gust of 41kts at Sand Key lighthouse. Gale warning issued for the coastal waters west of the 7 mile bridge.
http://www.ndbc.noaa.gov/station_page.php?station=sanf1

Much more wind than we had Sunday from Eta, looks like she's moving away now so I doubt we will get higher winds.

[Hammy]

Eye showing up on Key West radar

[EquusStorm]

Yeah this is super impressive at beam height from Key West. Probably near or maybe just over the hurricane threshold again. Be nice to have a recon mission in there immediately in case dry air forces a collapse soon but the storm certainly hasn't wanted to work with mission times.

[hiflyer]

I believe Vice President Pence is scheduled to be around Ft Myers this week on vacation....Looked at EYW and TPA radar and both show the eye feature now though better image off the Key West facility. And Casablanca radar out of Cuba is also showing the feature. Last look I had at Gulf water surface temps showed a fairly warm spot in that area coming up thru the Yucatan/Cuba gap.

[caneman]

Looks like we could be losing power here in Clearwater. Seems to be on track for Tarpon Springs. Just North of Clearwater. If it does go in there or up the bay, It doesn't look like it would weaken before hand

[robbielyn]

we r under hurricane watch per nhc 4am disco from Anna Maria to Yankeetown.

[Laser30033003]

it looks like some weakening is occurring at the same time as Storm is growing in size I'm basing this on water vapor imaging can anyone confirm this??

[robbielyn]

Looks like we could be losing power here in Clearwater. Seems to be on track for Tarpon Springs. Just North of Clearwater. If it does go in there or up the bay, It doesn't look like it would weaken before hand

per 4am disco landfall near cedar key big bend area. but we r under hurricane watch now.