ATL: LESLIE - Post-Tropical - Discussion

[chaser1]

and turning more northwesterly, no?

Actually, no, I don't see that. Appears still west or west-northwest.

I think there was an illusion of a northwest turn because the LLC has expanded and also gotten elongated a little from SW to NE.

[color=#4040FF]As Rock had recently posted, "the trough is there now". There is no doubt that LLC seems to be hellbent on trying to take that poleward NW motion that NHC keeps insisting will ocurr. More than likely I imagine this will occur however given the amount of shear that Leslie seems to be continuing to fight, along with this recent spat of "disjointed" lower/mid level issues these storms seem to be having, i'm going to sit back and pay greater attention to the motion of the overall envelope. The mean layer flow wants to keep Leslie moving westward and so long as she struggles, might continue to do so for a while.

[cycloneye]

From 5 PM Discussion.

THE GLOBAL MODELS ARE CONSISTENT IN
FORECASTING A BREAK IN THE SUBTROPICAL RIDGE IN A FEW DAYS
TIME...WHICH SHOULD CAUSE LESLIE TO TURN NORTHWESTWARD AND
NORTHWARD IN 3 TO 4 DAYS. BY THE END OF THE FORECAST...LITTLE
MOTION IS EXPECTED AS THE CYCLONE IS CAUGHT IN LIGHT STEERING
CURRENTS TO THE SOUTHEAST OF BERMUDA. THE OFFICIAL NHC PREDICTION
IS SHIFTED WESTWARD TO COME CLOSER TO THE DYNAMICAL MODEL
CONSENSUS... ALTHOUGH THE MODEL CONSENSUS IS STILL A BIT WEST OF
THE NEW FORECAST.

[cycloneye]

Here is Dr Jeff Masters latest discussion about Leslie and long range implications.

Tropical Storm Leslie a long-range threat to Bermuda, Canada, and the U.S. East Coast

Tropical Storm Leslie formed on Thursday in the Central Atlantic. Leslie's formation date of August 30 puts 2012 in 2nd place for earliest formation date of the season's 12th tropical storm. Only 1995 had an earlier formation date of the season's 12th storm. With records dating back to 1851, this year is only the second time 8 total storms have formed in August. The other year was 2004, when the first storm of the season formed on August 1 (Alex), and the 8th storm (Hermine) formed on August 29th. Satellite loops show that Leslie has a modest amount of heavy thunderstorm activity, and respectable low-level spiral bands and upper-level outflow. Conditions appear ripe to allow Leslie to intensify into a Category 2 hurricane by Sunday. Fortunately, Hurricane Kirk is weakening the ridge of high pressure to the north of Leslie, and Leslie is expected to turn to the northwest and miss the Lesser Antilles Islands. However, steering currents for Leslie are expected to collapse early next week, as Leslie gets stuck between two upper level lows. The storm will then slowly meander over the open ocean for many days, potentially threatening Bermuda. Leslie will stay stuck until a strong trough of low pressure approaches the U.S. East Coast around September 8. This trough should be strong enough to pull Leslie to the north and then northeast by September 9. At that time, Leslie may be close enough to the coast that the storm will make landfall in New England, Canada, or the Mid-Atlantic states. Leslie could also miss land entirely; this all depends upon the timing and strength of the September 8 trough of low pressure. Regardless, Leslie is expected to bring an extended period of high waves to the U.S. coast. According to NOAA's Wavewatch III model, large swells from Leslie will reach Bermuda by Monday, and arrive along the U.S. East Coast on Tuesday. These waves will be capable of creating dangerous rip currents and beach erosion

[jaxfladude]

Just what the basin needs; another threat.

[WilmingtonSandbar]

I know its to early to tell but everyone keeps talking about Florida what about NC anyones thoughts on what you think of it getting into our coast or close?

I'm getting that gitchy feeling down here. That one I always get about a week before a storm comes really close to me.

[jaxfladude]

Will there be a HH/Gulf-Stream flight(s), or is it too soon?

[SouthDadeFish]

Some remarkably deep convection firing, especially considering it is diurnal minimum:



Cloud tops well cooler than -80C!

[edurican]

What does the 5pm bulletin mean for the Lesser Antilles/Puerto Rico?

[cycloneye]

What does the 5pm bulletin mean for the Lesser Antilles/Puerto Rico?

Welcome to Storm2k. The 5 PM advisory means that Leslie will pass well Northeast of us. The only effects from it will be the high swells that will arrive to the North and East coast of the island starting on Sunday and maybe a few external bands may move thru during the weekend with the North to Northwest winds.

[Caesarp]

But will my Saturday Sunday or Monday in Nevis be affected by cloud cover or showers due to this darn thing if it stays on current predicted path?

Better than a direct hit, but 2 days with clouds and showers would stink. Not much to do when the sun isn't shining here. Hard to tell how far cloud cover extends from center.

[OuterBanker]

I'm starting to feel much better. Although it will stall there will be nothing to move it towards the US mainland. Most if not all models are now showing a north move after the stall. It still may be a threat to the northeast or Canada but I doubt anything south of that.

[Riptide]

I'm starting to feel much better. Although it will stall there will be nothing to move it towards the US mainland. Most if not all models are now showing a north move after the stall. It still may be a threat to the northeast or Canada but I doubt anything south of that.

It's an interesting situation if Leslie does decide to stall in that area; the GFS finally decides to move her out when it truncates and losses accuracy. Future model projections will keep changing for this one; as long as it remains 6+ days out. Small perturbations in the atmosphere can greatly alter the outcome of model projections; would be wise to watch this one not only for the possible historical stall but also for the potential landfall threat.

[ozonepete]

I'm starting to feel much better. Although it will stall there will be nothing to move it towards the US mainland. Most if not all models are now showing a north move after the stall. It still may be a threat to the northeast or Canada but I doubt anything south of that.

It's an interesting situation if Leslie does decide to stall in that area; the GFS finally decides to move her out when it truncates and losses accuracy. Future model projections will keep changing for this one; as long as it remains 6+ days out. Small perturbations in the atmosphere can greatly alter the outcome of model projections; would be wise to watch this one not only for the possible historical stall but also for the potential landfall threat.

One important note: A stall in that area would not be historical at all. It has happened many, many times. That is an area where steering winds are often very light to non-existent.

[Riptide]

I'm starting to feel much better. Although it will stall there will be nothing to move it towards the US mainland. Most if not all models are now showing a north move after the stall. It still may be a threat to the northeast or Canada but I doubt anything south of that.

It's an interesting situation if Leslie does decide to stall in that area; the GFS finally decides to move her out when it truncates and losses accuracy. Future model projections will keep changing for this one; as long as it remains 6+ days out. Small perturbations in the atmosphere can greatly alter the outcome of model projections; would be wise to watch this one not only for the possible historical stall but also for the potential landfall threat.

One important note: A stall in that area would not be historical at all. It has happened many, many times. That is an area where steering winds are often very light to non-existent.

A stall for 6 days? That hasn't been done before, at least in recorded meteorological history.

[ozonepete]

One important note: A stall in that area would not be historical at all. It has happened many, many times. That is an area where steering winds are often very light to non-existent.

A stall for 6 days? That hasn't been done before, at least in recorded meteorological history.

Yes, Inga in 1969 stalled for eight (8) days in that area.

[TropicalAnalystwx13]

I'd say Leslie has acquired enough organization to be declared a Category 1 hurricane on the Saffir-Simpson Hurricane Scale. Deep convection has persisted on top of the center during DMIN for several hours and outflow remains impressive in all four directions.

[Riptide]

One important note: A stall in that area would not be historical at all. It has happened many, many times. That is an area where steering winds are often very light to non-existent.

A stall for 6 days? That hasn't been done before, at least in recorded meteorological history.

Yes, Inga in 1969 stalled for eight (8) days in that area.

Wow, that's crazy. It's a shame I wasn't alive to see it. There seems to be an ideal forward speed for tropical cyclones as most stalled cyclones do not become very strong.

[Airboy]

Looks like more of a west movement than a WNW movement right now.

[ozonepete]

A stall for 6 days? That hasn't been done before, at least in recorded meteorological history.

Yes, Inga in 1969 stalled for eight (8) days in that area.

Wow, that's crazy. It's a shame I wasn't alive to see it. There seems to be an ideal forward speed for tropical cyclones as most stalled cyclones do not become very strong.

http://upload.wikimedia.org/wikipedia/c ... _track.png[/quote]

Yeah! That was the first season I ever tracked hurricanes. I was a young kid and tracked them on a little paper map with a pencil making dots and connecting them. You had to listen to the radio and watch the TV weather and pray really hard they'd give a location. When they actually gave co-ordinates you were in heaven. That being the first time I ever followed them I had no idea how unusual it was; I thought a lot of hurricanes did that, lol!

[Riptide]

Looks like more of a west movement than a WNW movement right now.

Some perspective on the scale of Leslie. Can't wait for this one to really get going.