ATL: ERIKA - Remnants - Discussion

[Aric Dunn]

convection would help slow it down some..

[AdamFirst]

A great post from Bryan Norcross on his Facebook page

The Dying Erika Dilemma

As a named tropical system, Erika is done, at least for now. But, despite rumors to the contrary, its weather is not. As expected, a combination of the mountains of Hispaniola and unfavorable atmospheric factors shredded the system as it moved past Haiti and toward Cuba. A new center swirl formed just north of the Cuban coast, but it’s not strong enough and it doesn’t have enough organized thunderstorm activity associated with it to count as a Tropical Storm or Tropical Depression.

BUT… there is windy, nasty weather just north and east of this center. And that nasty weather is going to spread through the Bahamas today and into South Florida late tonight and last at least through the day tomorrow (Sunday). Winds of 25-40 mph are widespread well away from what’s left of Erika. In addition, excessive tropical moisture will accompany the system, on top of the high moisture levels over Florida now.
The bottom line is that heavy rain squalls with gusty winds are expected across the state beginning in South Florida later tonight and spreading north. Flooding rain will be possible in some locations. Things should start to improve some in South Florida Monday, but will likely linger longer in Central and West Florida. In any case, the entire peninsula may be subject to heavy rain at times accompanied by gusty winds for the next several days.

There is some chance that ex-Erika might reorganize into Tropical Storm Erika again as it moves toward Florida. It would not be expected to intensify quickly, however, and, broadly, the weather over the state would not be much different than what we expect with Erika’s remnants. Drivers, especially of high-profile vehicles, and boaters need to be aware of the possibility of wind gusts strong enough to cause problems.

The dilemma here is that even though there is not much difference in the weather expected in Florida from the Remnants of Erika than if the system had held together as a Tropical Depression or 40 mph Tropical Storm, the alerting is very different. Winds at the coast could easily gust to Tropical Storm strength, but because the NHC rules don’t allow them to issue a Tropical Storm Watch – meaning winds of 40 mph or higher are possible – for a degenerated system (even if it might reorganize), they had to take down the watches and warnings. There are plans in place to fix this hole in the system, which can’t come too soon.

So let’s be happy that a hurricane isn’t coming. But beware that the Erika’s remnants may be accompanied by impactful weather. Be smart and don’t be surprised.

https://www.facebook.com/TWCBryanNorcro ... nref=story

[psyclone]

it's a deep slug of moisture that could really dump on someone and is therefore still worth following even absent development IMO.

[ronjon]

My information comes from the NHC discussion at 5 am and 9:30 am regarding slowing as the syetem approaches the western extent of the ridge. From NHC at 9:30 am disc:

The remnants are expected to move west-northwestward near the
northern coast of central and eastern Cuba for the next 12 to 24
hours and reach the southeastern Gulf of Mexico in about 36 hours.
After that time, a more northward motion is expected over the
eastern Gulf of Mexico.

The dynamical models suggests that the current strong wind shear
could relax by the time the system reachs the Gulf of Mexico, and
there is a possibility that Erika could regenerate.

[SoFla954]

it's a deep slug of moisture that could really dump on someone and is therefore still worth following even absent development IMO.

I second that opinion.

And AdamFirst, thanks for posting that from Bryan Norcross really explains why the NHC had to pull the watches and warnings.

[Aric Dunn]

models today will be interesting if they initialize the swirl..

[northjaxpro]

I think the only window of opportunity for a comeback for Erika will be during the next 36 hours. Once the remnants reach 80 degreesLongitude, That is the point where the southwest periphery of the ridge erodes. It is at that point in the Florida Straits in which I expect that vort to slow down as it rounds the periphery of that ridge and feels the weakness of the cut-off upper Low in the North Central GOM. Shear levels looking at reliable models in the Florida Straits look to drop around 10-15 kts the next 24-36 hours as the remnants moves through the Straits and moves into the extreme SE GOM by tomorrow morning. It is during this time that conditions for a brief time may allow it to spin-up into a TD at least or possibly a mimimal TS given the mid 80s ssts and in that region.

However, IF and it is a HUGE IF, Erika does regenerate, after about 48 hours from right now, the shear levels in the GOM are going to pick up substantially again as Ericka moves north being picked up by that trough. It will be a sheared mess again , but will be unfortunately bringing more heavy rainfall to the state next week. It will be a slow mover this week as the trough, although strong enough through the next 3-4 days to pick up Erika's remnants, looks to retrograde west due to ridging north and northeast of Florida in the Western Atlantic.

[ronjon]

Convection catching up to the LLC.

http://aviationweather.gov/adds/satellite/displaysat?region=CARIB&isingle=mult_big&itype=vis

[StormTracker]

models today will be interesting if they initialize the swirl..

Do you think they will, and what time do you think if they do?

[ronjon]

I think the only window of opportunity for a comback for Erika will be during the next 36 hours. Once the remnants reach 80 degreesLongitude, That is the point where the southwest periphery of the ridge erodes. It is at that point in the Florida Straits in which I expect that vort to slow down as it rounds the periphery of that ridge and feels the weakness of the cut-off upper Low in the North Central GOM. Shear levels looking at reliable models in the Florida Straits look to drop around 10-15 kts the next 24-36 hours as the remnants moves through the Straits and moves into the extreme SE GOM by tomorrow morning. It is during this time that conditions for a brief time may allow it to spin-up into a TD at least or possibly a mimimal TS given the mid 80s ssts and in that region.

However, IF and it is a HUGE IF, Erika does regenerate, after about 48 hours from right now, the shear levels in the GOM are going to pick up substantially again as Ericka moves north being picked up by that trough. It will be a sheared mess again , but will be unfortunately bringing more heavy rainfall to the state next week. It will be a slow mover this week as the trough, although strong enough through the next 3-4 days to pick up Erika's remnants, looks to retrograde west due to ridging north and northeast of Florida in the Western Atlantic.

Good analysis NorthJAX - spot on as usual.

[ronjon]

models today will be interesting if they initialize the swirl..

Do you think they will, and what time do you think if they do?

Aric, they probably will as NHC noted the swirl as the remnant center in their last disc.

[StormTracker]

I think the only window of opportunity for a comback for Erika will be during the next 36 hours. Once the remnants reach 80 degreesLongitude, That is the point where the southwest periphery of the ridge erodes. It is at that point in the Florida Straits in which I expect that vort to slow down as it rounds the periphery of that ridge and feels the weakness of the cut-off upper Low in the North Central GOM. Shear levels looking at reliable models in the Florida Straits look to drop around 10-15 kts the next 24-36 hours as the remnants moves through the Straits and moves into the extreme SE GOM by tomorrow morning. It is during this time that conditions for a brief time may allow it to spin-up into a TD at least or possibly a mimimal TS given the mid 80s ssts and in that region.

However, IF and it is a HUGE IF, Erika does regenerate, after about 48 hours from right now, the shear levels in the GOM are going to pick up substantially again as Ericka moves north being picked up by that trough. It will be a sheared mess again , but will be unfortunately bringing more heavy rainfall to the state next week. It will be a slow mover this week as the trough, although strong enough through the next 3-4 days to pick up Erika's remnants, looks to retrograde west due to ridging north and northeast of Florida in the Western Atlantic.

Good analysis NorthJAX - spot on as usual.

Agreed...

[robbielyn]

if we are on the ne side of the disturbance do spin up tornadoes occur or only once it becomes a ts do they form? let me ask an easier way. can td's and tropical waves create spinup tornadoes?

[JPmia]

I will say this.. those outflow boundaries should give us some fun later today if they continue wnw toward SFL.. sometimes those are just as nasty as the storm itself. Look at me, I am grasping for straws here..

http://wwwghcc.msfc.nasa.gov/cgi-bin/ge ... color=gray

[ronjon]

Looking more impressive on Cuban radar.

http://www.met.inf.cu/asp/genesis.asp?TB0=PLANTILLAS&TB1=RADAR&TB2=../Radar/07Holguin/hlgMAXw01a.gif

[AdamFirst]

if we are on the ne side of the disturbance do spin up tornadoes occur or only once it becomes a ts do they form? let me ask an easier way. can td's and tropical waves create spinup tornadoes?

Absolutely. Sometimes tornadoes occur in landfalling tropical systems in stronger feeder bands.

Just as an example, Tropical Storm Fay back in 2008 formed 50 tornadoes over the southeast United States, the strongest being an EF2 that touched down in Wellington, in western Palm Beach County Florida

[psyclone]

There's a bucket load of convection in the eastern gulf as well. most of it is offshore for now but if any of this eventually ambles onshore..look out for some heavy rain potential.

[robbielyn]

if we are on the ne side of the disturbance do spin up tornadoes occur or only once it becomes a ts do they form? let me ask an easier way. can td's and tropical waves create spinup tornadoes?

Absolutely. Sometimes tornadoes occur in landfalling tropical systems in stronger feeder bands.

Just as an example, Tropical Storm Fay back in 2008 formed 50 tornadoes over the southeast United States.

yes tropical storms do but what about waves and depressions?

[AdamFirst]

yes tropical storms do but what about waves and depressions?

It certainly is a possibility. NWS Miami mentioned an isolated tornado probability as ex-Erika approaches this morning.

[Extratropical94]

if we are on the ne side of the disturbance do spin up tornadoes occur or only once it becomes a ts do they form? let me ask an easier way. can td's and tropical waves create spinup tornadoes?

Absolutely. Sometimes tornadoes occur in landfalling tropical systems in stronger feeder bands.

Just as an example, Tropical Storm Fay back in 2008 formed 50 tornadoes over the southeast United States.

yes tropical storms do but what about waves and depressions?

Also possible. The rainbands with strong thunderstorms in them don't really know if they belong to a TS, a TD or a wave.