ATL: ALBERTO - Post-Tropical

[AtlanticWind]

This is a very likely outcome..

Latest UKMET brings a lot of rain to South Florida and Florida with a track very similar to the GFS. I am a bit skeptical of the ECMWF Central GOM solution to be quite honest, I think shear pushes a mass of moisture over to Florida with a track more in the EGOM and closer to Florida, we'll see though.

I respect your opinion but with the current guesstimated center being inland over the Yucatán wouldn’t that make the Euro more correct?

Where the center is now does not make the euro correct yet.
The GFS has the vorticity reforming to the east shortly ,we will see soon which model is nearest to the evolution
of the system.

[ronjon]

The tropical suite of models, cmc, gfs, and ukmet all move the low (or reform it) to the NE of its correct position in the Yuc.

[Dylan]

My latest update on 90L is posted to my Facebook page: https://www.facebook.com/DylanFedericoWx/

WEDNESDAY PM UPDATE ON TROPICAL DISTURBANCE 90L

Since yesterday afternoon, tropical disturbance #90L has continued to become slowly better organized. Visible satellite shows much more shower and thunderstorm activity near the center of circulation, which is currently located along the eastern Yucatan Peninsula near Belize. Despite this, the area of low pressure remains broad and disorganized. Invest 90L will slowly move northward into the Gulf of Mexico over the next couple of days, but a combination of land interaction, wind shear, and dry air will limit its ability to become a tropical depression or tropical storm #Alberto over the next two days. Which is why the National Hurricane Center is giving it a 0% chance of development over the next couple of days.

By Friday afternoon into Saturday, things will change. 90L is expected to emerge into the southern Gulf of Mexico, where conditions will be slightly more favorable for organization, and the National Hurricane Center gives 90L a 60% of becoming a tropical depression or tropical storm after day two. Wind shear and dry air will still limit development, but it won’t be lethal by any means. The disturbance will then be steered northward on the western periphery of the Bermuda high towards the north-central gulf coast by Sunday.

The European remains very consistent of a landfall in SE Louisiana early next week with strong support from its ensemble suite, along with the Japanese and German models. The Canadian and UK models are slightly east, with landfalls closer to the Alabama and Florida Panhandle coastlines. The American (GFS) model, which has been a complete embarrassment and is victimized by convective feedback issues, shows a landfall near the southern Florida peninsula. Even the GFS ensemble suite is well the west of its operational version, showing landfall from SE LA to the FL panhandle.

Bottom line that that confidence is strong for a landfall from SE LA to the western Florida panhandle. With conditions only being marginally favorable, I don’t expect 90L to become anything more than a weak, lopsided tropical storm. Meaning that the worst weather will be the EAST of the center. So, even if 90L makes landfall in SE LA, the worst weather would remain in Mississippi, Alabama, Florida, and Georgia. The primary concerns with this disturbance remains heavy rain and coastal flooding.

There is a potential for 90L to meander or even stall around the time of landfall early next week, due to a collapse in steering currents. If this happens, rainfall totals could greatly exceed what’s currently forecasted. Also, water temperatures well above normal along the northern gulf coast and could enhance the rainfall associated with this system. It’s still too early to know for sure where exactly 90L will make landfall and who will see the highest rainfall totals. However, SE LA to the western Florida panhandle look to be the areas of highest risk.

[chaser1]

I'm sticking with Panama City to Pensacola, perhaps with a stall then small cyclonic loop thrown in on approach.

[boca]

I wish wxman57 would give us his insight on 90L now since it’s looking like a north/central GOM issue now.

[boca]

[quote="Dylan"]My latest update on 90L is posted to my Facebook page: https://www.facebook.com/DylanFedericoWx/

WEDNESDAY PM UPDATE ON TROPICAL DISTURBANCE 90L

Since yesterday afternoon, tropical disturbance #90L has continued to become slowly better organized. Visible satellite shows much more shower and thunderstorm activity near the center of circulation, which is currently located along the eastern Yucatan Peninsula near Belize. Despite this, the area of low pressure remains broad and disorganized. Invest 90L will slowly move northward into the Gulf of Mexico over the next couple of days, but a combination of land interaction, wind shear, and dry air will limit its ability to become a tropical depression or tropical storm #Alberto over the next two days. Which is why the National Hurricane Center is giving it a 0% chance of development over the next couple of days.

By Friday afternoon into Saturday, things will change. 90L is expected to emerge into the southern Gulf of Mexico, where conditions will be slightly more favorable for organization, and the National Hurricane Center gives 90L a 60% of becoming a tropical depression or tropical storm after day two. Wind shear and dry air will still limit development, but it won’t be lethal by any means. The disturbance will then be steered northward on the western periphery of the Bermuda high towards the north-central gulf coast by Sunday.

The European remains very consistent of a landfall in SE Louisiana early next week with strong support from its ensemble suite, along with the Japanese and German models. The Canadian and UK models are slightly east, with landfalls closer to the Alabama and Florida Panhandle coastlines. The American (GFS) model, which has been a complete embarrassment and is victimized by convective feedback issues, shows a landfall near the southern Florida peninsula. Even the GFS ensemble suite is well the west of its operational version, showing landfall from SE LA to the FL panhandle.

Bottom line that that confidence is strong for a landfall from SE LA to the western Florida panhandle. With conditions only being marginally favorable, I don’t expect 90L to become anything more than a weak, lopsided tropical storm. Meaning that the worst weather will be the EAST of the center. So, even if 90L makes landfall in SE LA, the worst weather would remain in Mississippi, Alabama, Florida, and Georgia. The primary concerns with this disturbance remains heavy rain and coastal flooding.

There is a potential for 90L to meander or even stall around the time of landfall early next week, due to a collapse in steering currents. If this happens, rainfall totals could greatly exceed what’s currently forecasted. Also, water temperatures well above normal along the northern gulf coast and could enhance the rainfall associated with this system. It’s still too early to know for sure where exactly 90L will make landfall and who will see the highest rainfall totals. However, SE LA to the western Florida panhandle look to be the areas of highest risk.[/quote


Very good and informative write up

[cycloneye]

18z surface analysis.

[AdamFirst]

Just got an automated message from Alert St. Lucie at my job warning residents to stay off the roads during heavy rain spells over the weekend. Quoted saying the National Weather Service is predicting heavy rainfall for the area still.

Today was the first sunny, hot day we've had in Port Saint Lucie in nine days - and it's supposed to go south again tomorrow with more widespread rainfall ahead of the potential impacts from this system

[gatorcane]

This is a very likely outcome..

Latest UKMET brings a lot of rain to South Florida and Florida with a track very similar to the GFS. I am a bit skeptical of the ECMWF Central GOM solution to be quite honest, I think shear pushes a mass of moisture over to Florida with a track more in the EGOM and closer to Florida, we'll see though.

I respect your opinion but with the current guesstimated center being inland over the Yucatán wouldn’t that make the Euro more correct?

The GFS also has the "center" (i.e. the area of vorticity) over the Yucatan right now but late Friday/Sat timeframe, it develops a new area of vorticity well east of the Yucatan center (i.e. under sheared convection) and takes it NNE towards peninsula FL along the west coast on the right-edge of an Upper-Level low over the North-Central Gulf. The area of vorticity over the Yucatan weakens while pivoting east then NE and merges with the new area of vorticity.

[Dean4Storms]

Latest UKMET brings a lot of rain to South Florida and Florida with a track very similar to the GFS. I am a bit skeptical of the ECMWF Central GOM solution to be quite honest, I think shear pushes a mass of moisture over to Florida with a track more in the EGOM and closer to Florida, we'll see though.

I respect your opinion but with the current guesstimated center being inland over the Yucatán wouldn’t that make the Euro more correct?

The GFS also has the "center" over the Yucatan right now but on Friday it develops a new area of vorticity well east of the Yucatan center and takes it NNE towards peninsula FL along the west coast on the right-edge of an Upper-Level low over the North-Central Gulf. The area of vorticity over the Yucatan weakens while pivoting east then NE and merges with the new area of vorticity.

The GFS is just not as sharp with the trough over the Gulf as the others including its Ensembles. Models should have a better handle by at least the 12z runs tomorrow from what I read. But realistically I've not seen any NWS discussions throwing away completely the GFS runs but it does stand alone.

[stormlover2013]

Icon 18z run


https://www.tropicaltidbits.com/analysi ... 318&fh=120

[gatorcane]

Look at the shear ripping into the system keeping all of the convection over the NW Caribbean... GFS insists an area of vorticity will develop with time over the NW Caribbean under this convection. We'll see soon enough! The other thing I see is no movement north with the vorticity over the Yucatan. Seems stationary to me, maybe slight south drift but the sat imagery may be tricking my eyes

http://rammb.cira.colostate.edu/ramsdis ... display=12

[AJC3]

Going to all depend when the center forms

It's not really a question of where the center initially forms now. It's a matter of *if* there will be any downshear (NE/ENE) reformation(s) of the center toward where you might expect to get jet forced pressure falls in a high shear environment. If there aren't any, then the center will track north more toward the central Gulf Coast, closer to the non-GFS solutions. If it does take place, then you'll see a track which will wind up being a combination of a northward motion coupled with NE propagation of the center, which would take the center on an apparent NNE track over the eastern GOMEX or near/over Florida, which is closer to the OP-GFS.

[RL3AO]

It seems like the Atlantic is good for one of these systems every year in the May 20 to June 10 time frame. It'll look like garbage on satellite with all the rain to the north and east of the center. You'll have sunny skies 25 miles west of the landfall point with 10 mph winds. It'll bring a bunch of rain and maybe one ASOS station will record a 39 mph wind gust and this thread will have at least two pages worth of posts arguing that it should never have been named.

I'll check back on this post in a week or so.

[northjaxpro]

Going to all depend when the center forms

It's not really a question of where the center initially forms now. It's a matter of *if* there will be any downshear (NE/ENE) reformation(s) of the center toward where you might expect to get jet forced pressure falls in a high shear environment. If there aren't any, then the center will track north more toward the central Gulf Coast, closer to the non-GFS solutions. If it does take place, then you'll see a track which will wind up being a combination of a northward motion coupled with NE propagation of the center, which would take the center on an apparent NNE track over the eastern GOMEX or near/over Florida, which is closer to the OP-GFS.

This is the scenario I think we will see eventually pan out. Good explanation AJC3.

[Visioen]

It seems like the Atlantic is good for one of these systems every year in the May 20 to June 10 time frame. It'll look like garbage on satellite with all the rain to the north and east of the center. You'll have sunny skies 25 miles west of the landfall point with 10 mph winds. It'll bring a bunch of rain and maybe one ASOS station will record a 39 mph wind gust and this thread will have at least two pages worth of posts arguing that it should never have been named.

I'll check back on this post in a week or so.

What is different to me is the stalling potential.

[Dean4Storms]

Going to all depend when the center forms

It's not really a question of where the center initially forms now. It's a matter of *if* there will be any downshear (NE/ENE) reformation(s) of the center toward where you might expect to get jet forced pressure falls in a high shear environment. If there aren't any, then the center will track north more toward the central Gulf Coast, closer to the non-GFS solutions. If it does take place, then you'll see a track which will wind up being a combination of a northward motion coupled with NE propagation of the center, which would take the center on an apparent NNE track over the eastern GOMEX or near/over Florida, which is closer to the OP-GFS.

Not if you look at the 18z GFS..... it has the surface Low developing early Saturday maybe 50 miles west of Key West whereas just about all the other guidance is north of the Yucatan peninsula.

[CyclonicFury]

It seems like the Atlantic is good for one of these systems every year in the May 20 to June 10 time frame. It'll look like garbage on satellite with all the rain to the north and east of the center. You'll have sunny skies 25 miles west of the landfall point with 10 mph winds. It'll bring a bunch of rain and maybe one ASOS station will record a 39 mph wind gust and this thread will have at least two pages worth of posts arguing that it should never have been named.

I'll check back on this post in a week or so.

Reminds me of Colin from 2016. I know some people who passionately believe it was not a tropical cyclone.

[drewschmaltz]

Low pressure systems can form new "centers", that's established and important to this forecast as mentioned. Are any of those reasons present in this setup? Why would they (or wouldn't they) manifest.

[northjaxpro]

18Z GFS a bit stronger with the cyclone this run, 998 mb just north of Tampa Bay by 0Z Saturday evening, then inland North Florida by 6Z Sunday morning.