ATL: ARLENE - Post-Tropical

[cycloneye]

 https://twitter.com/wx_tiger/status/1664279787706413062

[chaser1]

Fairly stout 500 mb heights over South Texas and N. Mexico appear to be preventing any further northward motion in an otherwise flat (or weak) steering flow. Looks like a trough or cut-off low off Nova Scotia will begin to drop southwest and deepen in about 72-96 hours resulting in a northeast motion around that time.

[chaser1]

Overall i'd say this disturbance has relatively consolidated appearance. I personally think NHC will call off any recon for today but If convection is able to persist and a clear LLC becomes apparent then we'll see a recon flight tomm. and would then expect likely upgrade to TD perhaps tomorrow morning or afternoon. I dont think we quite have a closed LLC at the surface yet, but it sure is trying. I doubt that an authentic T.S. will develop given upper level conditions (but that rarely stopped NHC from pulling the trigger from numerous other past questionable GOM upgrades LOL). Maybe a "Potential Storm Watch" for Florida Southwest coast & S. Fla for Saturday/Sunday??

[wxman57]

Looks like it will peak within the next 12 hours or so as it tracks slowly southward. Will likely dissipate near western Cuba on Saturday. No Florida threat.

[Nimbus]

There is a frontal boundary that has dug way south with heavy shear ahead of it across Cuba.
Front missed so now we have the steering from the north on the back side of the front.

[boca]

Looks like it will peak within the next 12 hours or so as it tracks slowly southward. Will likely dissipate near western Cuba on Saturday. No Florida threat.

What about rain out of this,do you see that being a concern.

[wxman57]

Looks like it will peak within the next 12 hours or so as it tracks slowly southward. Will likely dissipate near western Cuba on Saturday. No Florida threat.

What about rain out of this,do you see that being a concern.

Not much rain for Florida, as it is very small and not moving any closer to Florida. Wind shear will cause squalls east of the center to gradually decline.

[tropicwatch]

Looks like it will peak within the next 12 hours or so as it tracks slowly southward. Will likely dissipate near western Cuba on Saturday. No Florida threat.

What about rain out of this,do you see that being a concern.

[Aric Dunn]

I seriously hope none of you are debating if this is a TD/TS already ( has been) or not.......

[Sciencerocks]

[Teban54]

If the LLC is tucked under the deep convection I believe we have TD 1. Banding features, deep convection, and pressure down to 1007 mb would meet the criteria.

Technically TD 2, but it will be TS Arlene if it gets 35 kt winds. The number 1 is used for the unnamed subtropical storm in January.

[cycloneye]

If the LLC is tucked under the deep convection I believe we have TD 1. Banding features, deep convection, and pressure down to 1007 mb would meet the criteria.

Technically TD 2, but it will be TS Arlene if it gets 35 kt winds. The number 1 is used for the unnamed subtropical storm in January.

Recon will find out this afternoon, what we have.

[cycloneye]

[Sciencerocks]

Based on the ascat I'd argue depression. This will probably become Arlene in the next 24 hours...

[Sciencerocks]

Buoy near storm shows nearly tropical storm force winds.

[AtlanticWind]

Looks like it will peak within the next 12 hours or so as it tracks slowly southward. Will likely dissipate near western Cuba on Saturday. No Florida threat.

What about rain out of this,do you see that being a concern.

Not much rain for Florida, as it is very small and not moving any closer to Florida. Wind shear will cause squalls east of the center to gradually decline.

South Florida under flood watch, NWS discussion talks about this upper low and 91L
continuing to pump moisture into the area thru Saturday with heavy rain expected to continue.

[CrazyC83]

One thing is for sure, this is a very unusual track, due south in the Gulf of Mexico. The building ridge is definitely helping out there.

[cycloneye]

70%

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Thu Jun 1 2023

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Northeastern Gulf of Mexico (AL91):
Recent satellite wind data, along with buoy and ship observations
indicate the area of low pressure over the northeastern Gulf of
Mexico has a broad but well-defined circulation with maximum
sustained winds of about 35 mph. Shower and thunderstorm activity
associated with the low is also showing signs of organization.
Environmental conditions remain marginally favorable for additional
development, and if these trends continue, a short-lived tropical
depression or storm is likely to form as soon as this afternoon. The
system is likely to meander over the northeastern Gulf of Mexico
through tonight but begin a slow southward motion on Friday. By
this weekend, environmental conditions are forecast to become
unfavorable for additional development as the system continues
moving southward, likely remaining offshore over the Gulf of Mexico.
An Air Force Reserve Hurricane Hunter aircraft is scheduled to
investigate the system later this afternoon.

Regardless of development, locally heavy rainfall could occur over
portions of the Florida Peninsula through this weekend. Additional
information on the rainfall and flooding potential can be found in
products issued by your local National Weather Service forecast
office and Excessive Rainfall Outlooks issued by the Weather
Prediction Center.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...70 percent.

Forecaster Papin/Cangialosi

[MarioProtVI]

Props to the mesoscales for absolutely nailing this. Most of the other models didn’t even as such develop a closed low from this system.

[Nimbus]

When recon gets there shortly they will probably find a closed circulation at about 1007 mb's.
Shear forecast and dry air over the gulf are comforting factors but I don't know if the NHC can just ignore recon data because a LLC is forecast to dissipate.