ATL: BRET - Remnants - Discussion

[bg1]

Wow, I thought it'd be 93L that would be renumbered first.
That RGB loop a page back does look like a fully-formed sfc low.

[Hammy]

If they wait till HH goes out to name this there might not be a bret. Either way impressive for june.

Satellite appearance now gives me the impression this is not closed, no banding, no evident spin--it likely was earlier but it almost certainly isn't now so they likely missed their chance to upgrade.

[Alyono]

There's clearly a center, Hammy

Now, this is running into the divergent shear I had previously discussed

[Hammy]

There's clearly a center, Hammy

Now, this is running into the divergent shear I had previously discussed

Is that the cause of the distorted satellite appearance?

[Alyono]

There's clearly a center, Hammy

Now, this is running into the divergent shear I had previously discussed

Is that the cause of the distorted satellite appearance?

yep. Models have been showing this as well

[Digital-TC-Chaser]

At some point this system may have a excellent outflow channel into to the upper-level
trough.

[Aric Dunn]

At some point this system may have a excellent outflow channel into to the upper-level
trough.

its already happening. upper environment is highly divergent for convection. not the best for a full fledged hurricane but could easily deepen enough to be a minimal hurricane.

[Digital-TC-Chaser]

Yeah i know it's divergent aloft has been for the past 24hrs. I was meaning
if the cell gets nice and circular aloft as most developing systems do in the uppers it may RI.

[Hammy]

Euro weaker, and no longer shows development, but in fact weakens it tomorrow.

[Hammy]

Convection where the circulation was supposed to be is rapidly weakening. Could be another sign that this is peaked and NHC missed the chance to upgrade.

[Aric Dunn]

Convection where the circulation was supposed to be is rapidly weakening. Could be another sign that this is peaked and NHC missed the chance to upgrade.

again the convection is developing as the LLC is moving along. very classic fast moving system.. they will likely find a 50 kt TS tomorrow.

[Hammy]

Convection where the circulation was supposed to be is rapidly weakening. Could be another sign that this is peaked and NHC missed the chance to upgrade.

again the convection is developing as the LLC is moving along. very classic fast moving system.. they will likely find a 50 kt TS tomorrow.

The convection near the 2am position point is what dissipated--which would indicate the convection outrunning the circulation, rather than vice-versa. I don't doubt they'll find some good winds out there, but I'm increasingly thinking they won't find a closed system, especially if the flight is later in the day--it appears to be moving too fast at this point.

[djones65]

Regardless of whether it is officially named or not tropical storm conditions are likely over the southern Windward islands later today. I hope everyone affected stays safe!

[Aric Dunn]

Convection where the circulation was supposed to be is rapidly weakening. Could be another sign that this is peaked and NHC missed the chance to upgrade.

again the convection is developing as the LLC is moving along. very classic fast moving system.. they will likely find a 50 kt TS tomorrow.

The convection near the 2am position point is what dissipated--which would indicate the convection outrunning the circulation, rather than vice-versa. I don't doubt they'll find some good winds out there, but I'm increasingly thinking they won't find a closed system, especially if the flight is later in the day--it appears to be moving too fast at this point.

I see the confusion. but if you look at the low level flow from the data its out running the convection . the upper divergence is supposed to move along with it for the next 36 to 48 hours or so before it runs into the shear axis.. just have to watch .. I have no doubts its closed at this point. looking at all available data.

[Hammy]

again the convection is developing as the LLC is moving along. very classic fast moving system.. they will likely find a 50 kt TS tomorrow.

The convection near the 2am position point is what dissipated--which would indicate the convection outrunning the circulation, rather than vice-versa. I don't doubt they'll find some good winds out there, but I'm increasingly thinking they won't find a closed system, especially if the flight is later in the day--it appears to be moving too fast at this point.

I see the confusion. but if you look at the low level flow from the data its out running the convection . the upper divergence is supposed to move along with it for the next 36 to 48 hours or so before it runs into the shear axis.. just have to watch .. I have no doubts its closed at this point. looking at all available data.

Is there any surface data to sift through at the moment? I know the ASCAT pass missed the center, and the storm is passing between two radar sites at the moment, which are certainly unhelpful in getting some conclusive idea one way or the other.

[Aric Dunn]

The convection near the 2am position point is what dissipated--which would indicate the convection outrunning the circulation, rather than vice-versa. I don't doubt they'll find some good winds out there, but I'm increasingly thinking they won't find a closed system, especially if the flight is later in the day--it appears to be moving too fast at this point.

I see the confusion. but if you look at the low level flow from the data its out running the convection . the upper divergence is supposed to move along with it for the next 36 to 48 hours or so before it runs into the shear axis.. just have to watch .. I have no doubts its closed at this point. looking at all available data.

Is there any surface data to sift through at the moment? I know the ASCAT pass missed the center, and the storm is passing between two radar sites at the moment, which are certainly unhelpful in getting some conclusive idea one way or the other.

if your looking for absolutes you wont find them ever in meteorology... But again so based on available data( all satellite derived like everyone else in the world at the moment) it shows all the signs of a classifiable tropical cyclone.

[Hammy]

Thanks to a microwave pass and some of the higher clouds have cleared out it appears the center is NW of the convection, not to the SE where I've been tracking--the convective activity appears to be on the inflow band to the south.

[NotoSans]

This is almost certainly a tropical cyclone according to microwave pass, but seems that the NHC wants some very concrete evidence (ASCAT or recon) of a closed circulation before making an upgrade.

[USTropics]

The NHC is going to wait for recon to confirm an LLC has formed it seems:

ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM

Potential Tropical Cyclone Two Discussion Number 3
NWS National Hurricane Center Miami FL AL022017
500 AM AST Mon Jun 19 2017

The cloud pattern associated with the disturbance hasn't changed
much overall, with a fairly compact cluster of deep convection near
the estimated center location. The Dvorak intensity estimate from
TAFB remains at 35 kt, and this value will be used for the advisory
intensity. The system has well-defined upper-level outflow over
the northern semicircle and vertical shear is forecast by the
dynamical guidance to remain low for the next day or so. Therefore
some intensification is forecast and the disturbance is likely to
become a tropical cyclone later today. After the system moves into
the Caribbean, it should encounter an increasingly hostile
environment of strong vertical shear associated with an upper-level
trough over the west-central Caribbean. The global models are in
good agreement on the system dissipating over the Central
Caribbean, and the official intensity forecast is slightly below
the model consensus at 48-72 h in deference to the global model
predictions.

The initial motion continues to be around 280/20 kt. The track
forecast philosophy is basically unchanged from the previous
advisory package. A well-defined ridge to the north of the
disturbance should continue to steer the system westward to
west-northwestward at a fast pace. By 48-72 hours, a slightly more
westward track is likely while the weakening system moves more with
the low-level tradewind flow. The official track forecast is close
to the previous one and very similar to the latest model consensus,
TVCN.

An Air Force Hurricane Hunter plane is scheduled to investigate
the system later today. Observations from the aircraft should
determine whether a well-defined center exists, i.e. whether the
disturbance has become a tropical cyclone.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0900Z 8.4N 54.5W 35 KT 40 MPH...POTENTIAL TROP CYCLONE
12H 19/1800Z 9.3N 57.4W 40 KT 45 MPH...TROPICAL CYCLONE
24H 20/0600Z 10.4N 61.1W 45 KT 50 MPH
36H 20/1800Z 11.5N 64.3W 40 KT 45 MPH
48H 21/0600Z 12.4N 67.6W 35 KT 40 MPH
72H 22/0600Z 13.5N 74.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 23/0600Z...DISSIPATED

$$
Forecaster Pasch

NNNN

[USTropics]

Essentially all of the GFS ensemble members dissipate TD2 within 66 hours: