6/12/06 FCST: Tropical Storm Alberto

[Jim Leonard]

74 knots at about 3000 feet.

looking rather more healthy that I expected...note how it appears the center may be reforming closer to the convection and stronger winds to the east.

that supports a 55-60 knot tropical storm.
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NHC has just posted hurricane warnings for portion of the upper west coast of Florida as Alberto has increased to 70mph and a pressure of 997mb.
The storm has moved on a more NE course so that has negated some of the shear and as let the convection develop closer to the center.

 

[Marcus Opitz]

Thinking of maybe heading more north west from here (Orlando metro area) to check this thing out. It looks like an early hurricane may be in store for Florida again…..I suppose one would not have to go to far west from hear as most of the nasty weather is on the east side of the storm…

 

[MClarkson]

the center has certainly reorganized properly... its in the middle of the stronger winds and very near the deep convection if you compare the lat long to satellite.

 

[Dan Dawson]

I've been watching an interesting little vortex, perhaps left over from the old circulation center, that has been tracking south all day away from the main circulation center of Alberto. It's even had some intermittent convective bursts go up near it, only to be quickly sheared off to the NE. You can see it particularly well at this site:

http://weather.msfc.nasa.gov/GOES/goeseastconus.html

Choose an animation loop length of 25 or so and make sure you click on 100% quality in the drop-down list. Then choose medium or high magnification and click on Alberto. The site's been a little slow today, but in my opinion this is the best satellite site out there for quality of images and frequency of images in an animation (I think they even go rapid scan when it is available), with the ability to zoom in anywhere on a point of interest.

 

[Jason Persoff]

I have two seemingly naive questions I'm going to post to this thread since it seems the forum rules mandate it be put here as it's a current event.

***There is a bow echo that has formed around Orlando in the immediate wake of a rainband. The movement of the bow was about 330/60 while the rainband appeared to be moving closer to 000/50. The bow briefly intensified then suddenly faded away. I was surpised to see a bow echo in an area where I thought subsidence would have been favored. I should have caught a screen cap, but by the time I thought about it, it was too late and the bow was mostly gone. Did anyone else see this? Thoughts?

***There is a frontal boundary moving SSE out of GA currently. In the next 12-18 hrs the first rainbands from TS Alberto are forecast to collide with this front. I've not seen fronts directly interact with rainbands before (mostly I think because I've not usually been geographically close to this kind of interaction--usually I'm just embedded in the TS or Hurricane well away from the fronts). Would this serve as a focus for severe weather (with significant intensification of convergence before they collide)?

For the first storm of the season, I'm fairly concerned to see the intensity of Alberto. The Gulf temps were warmer last year, but we haven't even hit summer. Very worrisome.

 

[Mike Johnston]

In the next 12-18 hrs the first rainbands from TS Alberto are forecast to collide with this front. I've not seen fronts directly interact with rainbands before (mostly I think because I've not usually been geographically close to this kind of interaction--usually I'm just embedded in the TS or Hurricane well away from the fronts). Would this serve as a focus for severe weather (with significant intensification of convergence before they collide)?
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Jason, I know I'm not qualified to answer your first question, but share an interest in your second question. The models seem to show the tropical low interacting with the stationary front over the next 48 hours, which should enhance convergence. Not sure about outright severe effects, but definitely concerned about heavy precipitation inland. Also, if the actual track is just a tad more north of current forecast, upslope flow could enter into the equation. Tropical systems bumping up against the Appalachians are notorious for producing extraordinary rain and flooding events.

It was interesting here today in Charleston, SC....just a bit too far south of the base of the upper trough and surface front, as the convection fired north and west of here. Thought the sea breeze boundary (which has been fairly strong over the last few days) might provide some focus for convection, but the cirrus from the tropical storm approached by mid-morning - and has steadily thickened through the day - keeping temps over the land down. Air down here has a very, very tropical feel, more like mid-August than mid-June. Now, this evening, just noticing some low level, scuddy clouds moving up from the south. Very interesting system to follow from this vantage point; will be interested to read any other replies to your forecast questions.

 

[Blake Michaleski]

The storm has made a fairly significant wobble/turn to the north now. movement looks to be almost due north at this time. This is judging from a zoomed in IR sat and TLH 88D analysis.

Also, weak/shallow convection is making an effort to wrap back around the center. If this does happen or if there is a nice convective blow up near the center, the deeper flow will again act to steer Alberto more to the east. .

I know a few chasers are in Cedar Key, Looks like that's gonna be a precip-free wind event now. Fun to play in but probably not what some had in mind. I'd roll up the coast some if at all possible towards but not quite making it to TLH.

 

[Jeff Snyder]

There may be one more flare-up in the works, but the very dry air right over the center of the storm doesn't bode well for any strengthening. In addition, operational models (e.g. NAM, GFS, etc) strengthen the 250mb flow over the area through today as a trough in the central Gulf deepens a bit. The very dry air (http://www.ssd.noaa.gov/goes/flt/t1/wv.jpg ) and likelihood that the shear won't decrease makes me think that Alberto may have hit it's peak intensity yesterday. The storm has looked rather marginal for most of it's lifetime, save the brief flare-up in convection that occurred yesterday early morning.

 

[Josh Morgerman]

Looking at the satellite imagery last night and this morning, I think it's over for this system. The inner core has no convection-- zero-- and it's taking on an extratropical appearance. (I guess I'm stating the obvious here.)

The water vapor imagery (below) is particularly telling. I have never seen a tropical cyclone with such a bone-dry core. That dry air just blasted right into this thing like a battering ram.

It's a disturbing and graphic image of a tropical cyclone's demise.

Note: This links is dynamic, so the above commentary will no longer apply as the system evolves.

 

[Josh Morgerman]

Interestingly, some good convection is suddenly firing up very near the LLC-- perhaps due to land interaction.

Of particular interest is the strong convective band wrapping completely around the W side of the center, which is clearly visible on Tallahassee radar. It's interesting because this system has been unable to achieve that during its whole lifecycle. In fact, this convective flare-up at the core makes Alberto looking quite a bit more tropical this morning versus last night.

Either way, the center is a few hours from landfall, and I would be surprised if the winds got up to 65 kt before then.

 

[Mike Johnston]

Experiencing the second heavy band of rain currently here in Charleston, SC, as the tropical low (still centered ~ 200 miles SW of here) is clearly fetching moisture from the Atlantic/Gulfstream. Although precip began here at about 11 am this morning, there were enough cloud breaks just offshore to heat the surface which has resulted in strong bands of convection to develop and move onshore. Low level shear was visible to the naked eye about an hour ago w/ the lower level flow moving from the ENE and occasionally I could peak up and see higher level flow from the SE. With the current rain band, even the surface winds seemed to alternate between SE'ly and NE'ly every few minutes. The rain drops with these tropical systems are so tiny, the rapid accumulations seem to defy logic, but I can report a dog food bowl filled to the brim in about 30 minutes' time with the first heavy rain band.

Local mets are emphasizing a tornado threat, although the expected 3"-5" of rain will likely be the most practical effect overnight in the low country. W/ the stationary front just to our north, I would not be surprised to see even more moisture "squeezed" out of this system over the next 12 hours.

I'll be heading out to the seashore on the Isle of Palms soon, as we expect at least two more heavy bands of convection to move in; and will hopefully be able to observe one before dark. As for the tornado threat, one really doesn't "chase" to a point in this environment....cloud bases are so low, the spin-ups are so brief, and with trees all around, the best one can do is take advantage of the visibility right along the shore and see what you can see. As I write this, TV report of a waterspout around Edisto Island right now is causing a local buzz.