ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[Cryomaniac]

Too much is being put into every "drift" or "wobble".

Wobble watching is a favourite pastime of this board.

[SoupBone]

On this loop, you can watch Alex as it has rounded the southwest extent of the subtropical ridge...currently Alex is trying to make a quick run to the north. Meanwhile, the next ridge is building over the Rockies and quickly moving east, filling in the current troughiness over the mid-South. Because the base of the trough is so far north (more than 10 degrees of latitude away), the northward pull is fairly weak, so I don't expect Alex to make too much poleward progress. The trough's base looks to be over the midwest (Iowa, Illinois, Indiana area), so it's just about to pass by the longitude of Alex, leaving Alex behind:

http://cimss.ssec.wisc.edu/tropic/real- ... 3java.html

Thanks for this explanation. I see exactly what you are mentioning.

[Sanibel]

Wrapping and big center burst. Here we go folks...

[KWT]

tolakram, gotta admit it does look like it, maybe the cause of it looking like that is the convection building up from the SW over the center?

That said sure looks like its got some easterly motion to it doesn't it?

[NEXRAD]

I can't see this drifting lasting much longer given the upper high is trying to build in, that being said the ECM really doesn't move this much in the next 24hrs, perhaps overall a slight WNW motion...

Yeah I do think there is a slow northerly drift, maybe a hint of easterly motion in that northerly drift. That upper ridge should build in, the only thing that could mess the forecast up is if a sneaky ULL decides to form on the SE side of that upper high...

http://www.ssd.noaa.gov/goes/east/watl/loop-wv.html

There is your ULL near the Bahamas....I'm not sure it it's gonna undercut the high but it sure is charging West.

The RUC has been persistent in ceasing the ULL's Wward movement tonight, which makes sense given the ridge and trough forcing. Look for the ULL to go stationary just east of the Nrn Bahamas before beginning a slow Nly move. It'll probably unfold as it interacts with the upper trough that will move offshore the SE US come tomorrow.

- Jay
South Florida

[Sanibel]

Still NNW in my opinion.


Getting enough water underneath it now that it is starting to rebound.

[clfenwi]

tolakram, gotta admit it does look like it, maybe the cause of it looking like that is the convection building up from the SW over the center?

That said sure looks like its got some easterly motion to it doesn't it?

Yeah, it's going to be interesting to see recon's center fix. I'm thinking the "apparent" easterly component of motion is the result of displaced convection. We shall find out soon.

[NEXRAD]

Per visible imagery, I'd estimate a low level circulation movement between NNW and N during the late afternoon. Alex certainly has an improving appearance, but it should be a good 6-hours or so before we see much for intensification.

- Jay
South Florida

[KWT]

Still NNW in my opinion.
Getting enough water underneath it now that it is starting to rebound.

Yeah it may well be the system is moving NNW, but its a really hard thing to tell now convection is blooming over the center. No doubts IMO we are starting to see increasingly favourable conditions aloft and thats allowing Alex to rebound again after that shear hit earlier today.

[ROCK]

I think I mention NE wobble about 5 posts back......the it will make a run at that weakness...BTW- that ridge sliding in from the west...that doesnt look all that potent if you ask me...

[NEXRAD]

The apparent NE wobble looks spurious to me on satellite imagery. It seems that its appearance was caused by a brief break in the mid/upper cloud cover thanks to some dry air working into Alex's NE circulation center area. If you compare IR and visible imagery, you can notice this (not to mention IRWV).

As for the ridging to build-in from the NW behind the Ern US trough, it's not an especially deep ridge, but will connect with the Atlantic ridging by sometime late Wednesday as the trough energy is ejected NE and into the north Atlantic. This will allow for a more Ely steering flow to become established with time. The more Alex remains glued to the Bay of Campeche, the greater chance that the ridging will build-in deep enough to prevent a U.S. landfall. Of course, such would not bode well for the NW coast of Mexico.

- Jay
South Florida

[Sambucol]

tolakram, gotta admit it does look like it, maybe the cause of it looking like that is the convection building up from the SW over the center?

That said sure looks like its got some easterly motion to it doesn't it?

Yeah, it's going to be interesting to see recon's center fix. I'm thinking the "apparent" easterly component of motion is the result of displaced convection. We shall find out soon.

How would an easterly motion change the track of the storm? Would it be more south or north in the track?

[CrazyC83]

About the strengthening of Alex - even if it rapidly intensifies while crawling, if it happens quite a while before landfall, shear would likely knock it back down before landfall...strongest landfall IMO potential is in 48-72 hours, a delayed landfall especially beyond 96 hours exposes it too much to the oncoming trough (sends it north but weakens it significantly).

[KWT]

FWIW its probably better if this storm can lift out just a little more than expected, the region close to the border is highly populated, esp compared to a little further north in the region where Bret hit...

I was thinking that maybe the case Jay, at least recon will give us a center fix soon so we know exactly where bout it is.

[NEXRAD]

tolakram, gotta admit it does look like it, maybe the cause of it looking like that is the convection building up from the SW over the center?

That said sure looks like its got some easterly motion to it doesn't it?

Yeah, it's going to be interesting to see recon's center fix. I'm thinking the "apparent" easterly component of motion is the result of displaced convection. We shall find out soon.

How would an easterly motion change the track of the storm? Would it be more south or north in the track?

If this apparent NE wobble is real, it wouldn't change the storm track much at all since the movement has been so minimal (slow and short-term). A persistent more eastward track over time won't necessarily change the eventual storm track that much from what I'm seeing. The storm is likely to have an eventual Wward to NWward turn. The main factor in how far south or north the system goes for final landfall has more to do with gains (or losses) in latitude rather than change in longitude.

- Jay
South Florida

[NEXRAD]

About the strengthening of Alex - even if it rapidly intensifies while crawling, if it happens quite a while before landfall, shear would likely knock it back down before landfall...strongest landfall IMO potential is in 48-72 hours, a delayed landfall especially beyond 96 hours exposes it too much to the oncoming trough (sends it north but weakens it significantly).

This would depend on where Alex would be located if it were to move far slower than any forecasts or guidance suggest. If the storm were still around the NW Gulf of Mexico offshore N or Central Texas come late Friday, the storm would enjoy a solid dual-channel outflow per GFS synoptic handling. That could allow a pretty potent storm. This, of course, is pure thought-experimenting. I am quite confident that Alex will be dissipating over land somewhere by Friday.

- Jay
South Florida

[KWT]

About the strengthening of Alex - even if it rapidly intensifies while crawling, if it happens quite a while before landfall, shear would likely knock it back down before landfall...strongest landfall IMO potential is in 48-72 hours, a delayed landfall especially beyond 96 hours exposes it too much to the oncoming trough (sends it north but weakens it significantly).

Yeah thats true, but I'd be surprised if this isn't inland by 96hrs, that would take a real bust from all the models...with an upper ridge to the north of the system thats when you tend to find the most favourable conditions as you rightfully suggest...

[Clint_TX]

Wrapping and big center burst. Here we go folks...

Yep

[TeamPlayersBlue]

Not gonna lie, i dont see any wobbles lol. That storm looks pinned. Either way. I dont want this to happen, but for this storm to make a landfall around Corpus Christi or Victoria, what has to happen and is that a VERY plausible scenario? Sorry ive been reading the forum all day and looking at the maps but can see the major players. Ive seen a spin in La, a what seems to be a slight trough in NE Texas, and the high pressure racing in from the Rockies. Which is the major player?

[Air Force Met]

I guess my eyes are playing tricks on me. I swear on the vis Alex appears to have made a considerable jog to the North or even NNE. just saying.....and no I'm not making any landfall implications...just an observation.

I don't think your eyes are playing tricks on you. That is what I see too.