ATL: JULIAN - Post-Tropical

[zhukm29]

An explosion of convection at the end... quite surprising since this wasn't expected to get going until later this week, and it was a naked swirl this morning.

[AlphaToOmega]

Why does the GFS hate this system?

[Sciencerocks]

[AlphaToOmega]

A trough of low pressure located over the central Atlantic about
600 miles east of Bermuda continues to produce disorganized showers
and thunderstorms. Environmental conditions are forecast to be
generally conducive for development, and a tropical depression
is likely to form late this week or this weekend while the system
moves slowly eastward at 5 to 10 mph.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...70 percent.

[AlphaToOmega]

I cannot believe how badly the models are performing with this system! First they show development; then they show no development. The ECMWF and ICON show development, but the GFS and CMC show no development. Have the models always been this awful, or is this a new thing?

[Sciencerocks]

[tolakram]

I cannot believe how badly the models are performing with this system! First they show development; then they show no development. The ECMWF and ICON show development, but the GFS and CMC show no development. Have the models always been this awful, or is this a new thing?

What type of plots are you looking at? Vorticity is your friend here, rather than an MSLP plot. Take this to the model thread?

[cycloneye]

An elongated area of low pressure located over the central Atlantic
about 600 miles east of Bermuda continues to produce disorganized
showers and thunderstorms. Environmental conditions are forecast
to be generally conducive for development, and a tropical depression
is likely to form this weekend. The system is expected to move
slowly eastward during the next day or two, but a faster
northeastward motion is forecast to begin on Sunday.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

[Hammy]

I cannot believe how badly the models are performing with this system! First they show development; then they show no development. The ECMWF and ICON show development, but the GFS and CMC show no development. Have the models always been this awful, or is this a new thing?

It's a small system so its entirely possible they aren't resolving it properly.

[Sciencerocks]

[cycloneye]

An elongated area of low pressure located over the central Atlantic
about 650 miles east of Bermuda is producing disorganized showers
and thunderstorms. Environmental conditions are forecast to be
generally conducive for development, and a tropical depression is
likely to form over the weekend. The system is expected to move
slowly eastward during the next day or two, but a faster
northeastward motion is forecast to begin on Sunday.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

[Sciencerocks]

[AlphaToOmega]

I would be extremely surprised if this does not develop. It was at code red for such a long time, and conditions still seem favorable for development.

An elongated area of low pressure located over the central Atlantic
about 650 miles east of Bermuda is producing disorganized showers
and thunderstorms. Environmental conditions are only forecast to be
marginally conducive for development, but a tropical depression
could still form over the weekend. The system is expected to move
slowly eastward during the next day or two, but a faster
northeastward motion is forecast to begin on Sunday.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...60 percent.

[AlphaToOmega]

This is so close to having a closed circulation. All it needs is southeasterly flow.

[AlphaToOmega]

In my opinion, Invest 97L is classifiable. ASCAT shows a closed circulation. 12Z surface analysis shows a closed low. Moreover, 12Z GFS, CMC, and ICON surface analyses all show closed lows.

[CyclonicFury]

In my opinion, Invest 97L is classifiable. ASCAT shows a closed circulation. 12Z surface analysis shows a closed low. Moreover, 12Z GFS, CMC, and ICON surface analyses all show closed lows.
https://i.postimg.cc/nhVqZP2R/ascat-97-L-barb-202108271314.png
https://i.postimg.cc/0N0gmrD2/USA-12Z.gif
https://i.postimg.cc/JnCNw42J/gfs-mslp-wind-atl-1.png
https://i.postimg.cc/8ctMrdPB/gem-mslp-wind-atl-1.png
https://i.postimg.cc/FsC0rx6h/icon-mslp-wind-atl-1.png

That looks very broad and elongated. Convection has also decreased since yesterday and is not well organized. Doesn't appear classifiable to me, at all.

[Sciencerocks]

[Sciencerocks]

[Sciencerocks]

[AlphaToOmega]

Invest 97L never ceases to confuse

Showers and thunderstorms associated with an elongated area of low
pressure located over the central Atlantic has become a little
better organized overnight. Environmental conditions are
expected to be only marginally conducive for further development.
However, a tropical depression could still form wtihin the next
couple of days. By midweek, the system is forecast to be absorbed
by a frontal system. The disturbance is expected to drift eastward
through today, then accelerate northeastward Sunday toward the
central north Atlantic.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.