Low Pressure over Southwest Florida

[Aric Dunn]

Need to watch the sagging front/some remants of sally. there is a developing circ along the boundary and convection is building with it.

some ensemble members have been back and forth with something possible coming together.

and since there is already TS with it and surge coming into saint augustine and palm coast. figured it was time for a thread.

[Aric Dunn]

[northjaxpro]

A surface trough was forecast to develop by tomorrow morning in conjuction with our ongoing nor'easter in progress currently along the Northeast Florida coast.

We have been getting strong northeast winds here along the coast with gusts upward to near 40 mph. We are getting a pretty good pressure gradient squeeze with the big High to our north and the inverted trough just off the coast.

[Sciencerocks]

The irony of this coming back and doing an ivan. Oh'man, another similarity.

[AnnularCane]

The irony of this coming back and doing an ivan. Oh'man, another similarity.

She might run into Beta if she did that though.

[AJC3]

This occurs frequently with early fall "back door fronts" here in Florida. Generally, the wind shift along these boundaries is about 120-150 degrees, which results in a large swath of low level vorticity in a broad area surrounding the boundary. We often see multiple transient vortices form along these zones, and this one is no different. Check out the radar time lapse out of Melbourne, and you can see several weak/transient swirls along the boundary. There's a very defined one just inland from the coast about 15 miles north of Melbourne that has been dropping SSW all afternoon. You can see it in Aric's satellite time lapse, at the western edge. It winds up a little NNE of Cape Canaveral in the final frame. The vortex Aric mentioned is also apparent, between 29.5-30.0N and 78.5-79.0W and drifting south. It's slow motion is due to it having more vertical depth (winds aloft are actually weaker than near the surface).

http://moe.met.fsu.edu/~mnissenbaum/Rad ... /loop.html (time sensitive).

Another of these swirls became more vertically deep and slowed to a crawl along/offshore the Volusia County coast, resultng in 3-6" of rain since early this afternoon.

[psyclone]

A busy northeast wind is a sure sign of a glorious seasonal change. Such a pattern is a delight on the west coast with a refreshing offshore wind. Not such a nice pattern for the east coast club but it is nice to see Fall nosing in.

[Aric Dunn]

This occurs frequently with early fall "back door fronts" here in Florida. Generally, the wind shift along these boundaries is about 120-150 degrees, which results in a large swath of low level vorticity in a broad area surrounding the boundary. We often see multiple transient vortices form along these zones, and this one is no different. Check out the radar time lapse out of Melbourne, and you can see several weak/transient swirls along the boundary. There's a very defined one just inland from the coast about 15 miles north of Melbourne that has been dropping SSW all afternoon. You can see it in Aric's satellite time lapse, at the western edge. It winds up a little NNE of Cape Canaveral in the final frame. The vortex Aric mentioned is also apparent, between 29.5-30.0N and 78.5-79.0W and drifting south. It's slow motion is due to it having more vertical depth (winds aloft are actually weaker than near the surface).

http://moe.met.fsu.edu/~mnissenbaum/Rad ... /loop.html (time sensitive).

Another of these swirls became more vertically deep and slowed to a crawl along/offshore the Volusia County coast, resultng in 3-6" of rain since early this afternoon.

Yeppers.. and occasionally they eventually do organize. This one in particular is going to sag much farther south than usual giving it some decent chances..

[Aric Dunn]

funny story how un-named tropical lows can produce interesting weather.. lol

[AJC3]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sun Sep 20 2020

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

A small low pressure system is located near a frontal boundary, just
off the eastern coast of central Florida. The low is producing a
small area of thunderstorms near the coast, and recent buoy and
satellite-derived wind data indicate that gale-force winds are
occuring in the area. The low is expected to move inland over
Florida later this morning, and significant development is not
anticipated. For more information on this system, please see local
products and High Seas Forecasts issued by the National Weather
Service.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...10 percent

[northjaxpro]

Yes, a big convective blow'up.near a circulation just off the coast of Melbourne. A 1011 mb Low Pressure, which is just ahead of a frontal boundary. This is a remnant of ex-Sally, which has dropped south- southwest for several days to now. We definitely have had a strong gradient of northeast wind here along the coast with the big 1033 mb High over New England and the Low Pressure area just east of Melbourne currently. Winds gusting to over 40 mph have ocvured overnight along the coast and there is inland tidal flooding , which is occring along the Saint Johns River in the Jax area. NWS Jax has posted a warning for this, which has been extended through tomorrow afternoon.

It s not anticipated to initially develop, but if it continues to drift south , and stays off shore, looking at the windshear analysis, it drops off the coast.of Southeast Florida and the area between there in the NW Bahamas. NHC gives it a 10% probability. There are very warm ssts near the Gulf Stream just off shore as well



You never know. It seems like every decent vorticity is developing in this insane year.

[ronjon]

The ICON and to a lesser extent GFS have been developing a weak low or vorticity max from this feature that gets shunted south to the Florida Straits and then moves NW into the SE GOM and eventually northward off the west coast of FL. No model develops it more than a weak low but several models show it moving northward in the eastern Gulf late week with a moisture surge after the Teddy induced front sweeps the high humidity from most of the state Monday through Wed.

[Emmett_Brown]

Both the GFS and Euro show ex Sally's vort moving SW across FL into the SE GOM. GFS wants to take it W toward the central GOM, interacting with Beta. Euro keeps it closer to FL, brings it back up the W coast of FL later in the week. The GFS shows some shear over the GOM, with pockets of lower shear in the SE GOM in a few days. Dry air not much of a problem. Shear will be marginal. If ex Sally's vort finds a pocket of lighter upper level winds it could develop. Seriously, it doesn't look like much now, but we have seen so many systems spin up from relatively benign amounts of spin, I wouldn't be surprised to see some home brew out of this, maybe a low end TS.

[Emmett_Brown]

Both the GFS and Euro show ex Sally's vort moving SW across FL into the SE GOM. GFS wants to take it W toward the central GOM, interacting with Beta. Euro keeps it closer to FL, brings it back up the W coast of FL later in the week. The GFS shows some shear over the GOM, with pockets of lower shear in the SE GOM in a few days. Dry air not much of a problem. Shear will be marginal. If ex Sally's vort finds a pocket of lighter upper level winds it could develop. Seriously, it doesn't look like much now, but we have seen so many systems spin up from relatively benign amounts of spin, I wouldn't be surprised to see some home brew out of this, maybe a low end TS.

First visible image clearly shows a tight low center onshore in EFL, just inland from Melbourne heading SW

[Stangfriik]

Ok this is why it feels so tropical. Very gusty today in Daytona

[rockyman]

Low level swirl of clouds moving WSW north of Okeechobee this morning. Winds at the Okeechobee Airport from west most of the morning.

[northjaxpro]

Low level swirl of clouds moving WSW north of Okeechobee this morning. Winds at the Okeechobee Airport from west most of the morning.

Yes indeed. It shows quite nice on visible imagery. It continues moving southwest, as it has for the past several hours.

[TheStormExpert]

Should bring some wet weather here in coastal Palm Beach County at least this afternoon.

[mrbagyo]

[Emmett_Brown]

I'm interested to see if south FL convection gets going this afternoon over land to the S of the low, and whether it might give the low a boost.