ATL: ERIKA - Remnants - Discussion

[ronjon]

And when you see a TS building good convection over the LLC during DMIN, look out.

Not a system you would want to see get into open waters on a track to Florida.

Westerly shear is forecast to worsen the next two days. Not likely to strengthen over the short term.

[Hammy]

http://199.9.2.143/tcdat/tc15/ATL/05L.ERIKA/ssmi/color/2degreeticks/20150827.1846.f15.x.colorpct_85h_85v.05LERIKA.40kts-1006mb-166N-635W.66pc.jpg

Three hour difference earlier when organization began, the LLC actually got pulled northeast.

[USTropics]

Saved image of the LLC clearly being tugged under the convection and then immediately building cloud tops:

[NDG]

Saved image of the LLC clearly being tugged under the convection and then immediately building cloud tops:

http://i.imgur.com/8EwCdFP.gif

Got to love how these events happen, I am sure some laws of fluids have something to do with this.

[deltadog03]

I agree that convection is getting closer to the center. Will be interesting to see if the shear can stay relaxed...or keep decreasing sooner rather than later.

[fci]

I don't think anything is "taking off" until this storm clears the Islands and Shear that it is approaching. Low Level Center is to the west of everything and there have been centers that have gone away only to reform elsewhere. Until it is past Hispanola it's all noise, pulse up pulse down. True formation comes in a day or so; or possibly not at all.
Disclaimer below

[ozonepete]

And when you see a TS building good convection over the LLC during DMIN, look out.

Not a system you would want to see get into open waters on a track to Florida.

Westerly shear is forecast to worsen the next two days. Not likely to strengthen over the short term.

The NHC said "shear expected to be fairly strong", not increasing. And whether that happens or not, it is clear from the visible satellite images that the shear between it and PR is pretty low right now, I think because the ULL over Cuba is starting to weaken and/or retrograde westward now. That's why there's a window to ramp up now and overnight.

[SunnyThoughts]

PRESENT MOVEMENT...WNW OR 285 DEGREES AT 15 MPH...24 KM/H


Taken from the 5pm advisory wnw as opposed to w

[NDG]

This buoy is under the convection just a few miles SSE of LLC.

Conditions at 42060 as of
(3:50 pm AST)
1950 GMT on 08/27/2015:
Unit of Measure: Time Zone:
Click on the graph icon in the table below to see a time series plot of the last five days of that observation.

5-day plot - Wind Direction Wind Direction (WDIR): SSE ( 160 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 31.1 kts
5-day plot - Wind Gust Wind Gust (GST): 36.9 kts
5-day plot - Wave Height Wave Height (WVHT): 4.9 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 9 sec
5-day plot - Average Period Average Period (APD): 5.0 sec
5-day plot - Mean Wave Direction Mean Wave Direction (MWD): E ( 89 deg true )
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.75 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): +0.00 in ( Steady )
5-day plot - Air Temperature Air Temperature (ATMP): 77.4 °F
5-day plot - Water Temperature Water Temperature (WTMP): 83.5 °F
5-day plot - Wind Speed at 10 Meters Wind Speed at 10 meters (WSPD10M): 33.0 kts
5-day plot - Wind Speed at 10 Meters Wind Speed at 20 meters (WSPD20M): 35.0 kts
5-day plot - Wind Speed, Wind Gust and Atmospheric Pressure Combined plot of Wind Speed, Gust, and Air Pressure

http://www.ndbc.noaa.gov/station_page.php?station=42060

[Aric Dunn]

Not a system you would want to see get into open waters on a track to Florida.

Westerly shear is forecast to worsen the next two days. Not likely to strengthen over the short term.

The NHC said "shear expected to be fairly strong", not increasing. And whether that happens or not, it is clear from the visible satellite images that the shear between it and PR is pretty low right now, I think because the ULL over Cuba is starting to weaken and/or retrograde westward now. That's why there's a window to ramp up now and overnight.

And this is important since ... the better organized it can get before dealing with the islands the better shot it has to survive.

[ozonepete]

I don't think anything is "taking off" until this storm clears the Islands and Shear that it is approaching. Low Level Center is to the west of everything and there have been centers that have gone away only to reform elsewhere. Until it is past Hispanola it's all noise, pulse up pulse down. True formation comes in a day or so; or possibly not at all.
Disclaimer below

Hey fci! Haven't talked with you in a while. Just one important point. The storm LLC is already under the convection right now and there are a number of hot towers firing over the center so it is no longer "unstacked". Take a look at the vis satellite or even better, the RGB.

[SouthDadeFish]

The events that transpired this afternoon are quite odd. For whatever reason, I have noticed that the convective envelope associated with the mid level circulation rapidly proceeded westward toward the exposed LLC. Coinciding with this event, the LLC became essentially stationary. The end result appears to be a much better defined surface circulation on visible satellite imagery and possibly a better organized storm as recon may confirm shortly.

This morning it was apparent that outflow was fairly solid in all quadrants. I hypothesize that Erika was being affected by some mid-level shear, which undercut the outflow layer and prevented the stacking of the low and mid level vortices. However, such mid level shear appears to have abated and the low and mid level vortex is becoming more aligned.

[N2FSU]

If nothing else, the slower movement has brought a halt to the self-induced shear.

Edit: Interesting that there is no mention of the Euro in the 5pm discussion.

I thought it was interesting also that they didn't mention the Euro. Doesn't look like they bought too much into the big west swing, as evidenced by the 5pm track.

[NDG]

Not a system you would want to see get into open waters on a track to Florida.

Westerly shear is forecast to worsen the next two days. Not likely to strengthen over the short term.

The NHC said "shear expected to be fairly strong", not increasing. And whether that happens or not, it is clear from the visible satellite images that the shear between it and PR is pretty low right now, I think because the ULL over Cuba is starting to weaken and/or retrograde westward now. That's why there's a window to ramp up now and overnight.

I wonder if they are talking more in line with ML shear, because as if Erika is now starting to develop its own UL anticyclone on top of her by looking at the satellite loop..

[Aric Dunn]

The events that transpired this afternoon are quite odd. For whatever reason, I have noticed that the convective envelope associated with the mid level circulation rapidly proceeded westward toward the exposed LLC. Coinciding with this event, the LLC became essentially stationary. The end result appears to be a much better defined surface circulation on visible satellite imagery and possibly a better organized storm as recon may confirm shortly.

This morning it was apparent that outflow was fairly solid in all quadrants. I hypothesize that Erika was being affected by some mid-level shear, which undercut the outflow layer and prevented the stacking of the low and mid level vortices. However, such mid level shear appears to have abated and the low and mid level vortex is becoming more aligned.

Agreed. There was clearly some sort of re-organization that went on this morning.

[NDG]

The events that transpired this afternoon are quite odd. For whatever reason, I have noticed that the convective envelope associated with the mid level circulation rapidly proceeded westward toward the exposed LLC. Coinciding with this event, the LLC became essentially stationary. The end result appears to be a much better defined surface circulation on visible satellite imagery and possibly a better organized storm as recon may confirm shortly.

This morning it was apparent that outflow was fairly solid in all quadrants. I hypothesize that Erika was being affected by some mid-level shear, which undercut the outflow layer and prevented the stacking of the low and mid level vortices. However, such mid level shear appears to have abated and the low and mid level vortex is becoming more aligned.

I totally agree.

[ozonepete]

The NHC said "shear expected to be fairly strong", not increasing. And whether that happens or not, it is clear from the visible satellite images that the shear between it and PR is pretty low right now, I think because the ULL over Cuba is starting to weaken and/or retrograde westward now. That's why there's a window to ramp up now and overnight.

I wonder if they are talking more in line with ML shear, because as if Erika is now starting to develop its own UL anticyclone on top of her by looking at the satellite loop..

Yeah I think you're right. ML shear is the important one here.

[SunnyThoughts]

The events that transpired this afternoon are quite odd. For whatever reason, I have noticed that the convective envelope associated with the mid level circulation rapidly proceeded westward toward the exposed LLC. Coinciding with this event, the LLC became essentially stationary. The end result appears to be a much better defined surface circulation on visible satellite imagery and possibly a better organized storm as recon may confirm shortly.

This morning it was apparent that outflow was fairly solid in all quadrants. I hypothesize that Erika was being affected by some mid-level shear, which undercut the outflow layer and prevented the stacking of the low and mid level vortices. However, such mid level shear appears to have abated and the low and mid level vortex is becoming more aligned.

Agree also, and D-max to come in a few hours.

[AutoPenalti]

What exactly is an anti-cyclone?

[psyclone]

I agree the system appears to be organizing this afternoon, albeit from a poor baseline. it will be very interesting to see if this can persist as we head toward Dmax.