cjzydeco
(Weather Guru)
Wed Aug 29 2012 01:37 AM
Re: Hurricane Leslie Forecast Lounge

This one has caught my attention all week while I was watching model runs for Isaac. Early model runs had it approaching as near as the Bahamas as a TS or even a Cat 1 hurricane, but based on more recent runs, looks like it will approach the Lesser Antilles and then recurve.

Title edited to reflect upgraded status


cieldumort
(Moderator)
Wed Aug 29 2012 01:52 AM
Hurricane Leslie Forecast Lounge

A large, but still rather unorganized area of low pressure associated with a tropical wave is being tracked as Invest 98L. Models are somewhat bullish on this system, and so we will start a Lounge for 98L at this time.

As of 9:00 PM EDT Aug. 28, Invest 98L was located roughly 400 miles west-southwest of the Cape Verde Islands, and movement was to the west or west-northwest at around 15 MPH. There are presently some indications that the disturbance may be trying to consolidate a little to the northwest of where it has most recently been analyzed at.

This is where to put long range best guesses on intensity and forecast track for this feature. Long range model output discussions are also appropriate here.

Edited to reflect upgrades on 08/30 and 09/05


WeatherNut
(Weather Master)
Wed Aug 29 2012 09:14 PM
Re: Invest 98L Forecast Lounge

98L is looking much better today. It has more thunderstorms near the center of rotation and seems to be establishing outflow on east and west sides

ftlaudbob
(Storm Chaser)
Wed Aug 29 2012 11:57 PM
Re: Invest 98L Forecast Lounge

98L is up to 70% now.Time to watch this one.

LoisCane
(Veteran Storm Chaser)
Thu Aug 30 2012 12:04 AM
Re: Invest 98L Forecast Lounge

Been watching it... for now it looks like it would stay out to sea but something bothers me about it. And, i think a long range forecast and the models are a wait and see situation. With Isaac on the map, things are very fluid in ways.

WeatherNut
(Weather Master)
Thu Aug 30 2012 06:02 AM
Re: Invest 98L Forecast Lounge

I dont think this is a lock to recurve. Its been moving steadily west at 14N all day. I will say looking at the latest SAT loop...this thing is almost certainly Leslie already. Tomorrow it will pass right over buoy 41041...so we will have a little more info. Pressures are falling there now and winds are out of the North

Myles
(Weather Hobbyist)
Thu Aug 30 2012 01:08 PM
Re: Invest 98L Forecast Lounge

98L is now being labelled 12L, so looks like it's getting the bump to depression. Most models still want to recurve it, but are also showing some potential for the front leaving it behind and it stalling around 30N/60W, and the euro does stall it there for 2 days. Of course. 7 days model tracks are highly unreliable, but it will certainly interesting to see how this one unfolds.

MichaelA
(Weather Analyst)
Thu Aug 30 2012 01:24 PM
Re: Invest 98L Forecast Lounge

Seven days out I don't rely on very much, but it does seem plausible that 98/12L will recurve into the Atlantic possibly threatening Bermuda. I also see the models showing the potential of this system becoming the season's first major hurricane.

Joeyfl
(Weather Guru)
Thu Aug 30 2012 04:09 PM
Re: Invest 98L Forecast Lounge

While it is hard to argue against the models taking this recurve north just east of Bermuda, it is not completely a for sure thing. It is something to keep an eye on as just few days ago the GFS/Euro had it coming much further west. It is a tough call on whether it will get trapped and then ridge build back in, which maybe possible, or it feels the weakness left behind from a departing Kirk???Time will tell but keep an eye on it heading into the holiday weekend and watch for any changing trends.

WeatherNut
(Weather Master)
Thu Aug 30 2012 05:06 PM
Attachment
Re: Invest 98L Forecast Lounge

I think the models are over emphasizing Kirk's influence. Kirk is a very small storm and any break in the ridge will quickly fill in. Also it looks like dry air is doing its deed as the convection on the east side isn't as robust (the depression). It is also moving due west which will have it miss the next forecast point to the south. The Euro seems to want to take it more west (I've heard that one before this season). A couple of days will provide a little more clarity perhaps.
Side note...this is about to go almost directly over buoy 41041 with now has pressure falling and a sustained wind of 29kts and a gust of 35kts out of the NNW (as of 12:50 EST)
I attached the plot


ftlaudbob
(Storm Chaser)
Thu Aug 30 2012 06:07 PM
Re: Invest 98L Forecast Lounge

We now have Tropical Storm Leslie.Moving west and is expected to strengthen.

Quote:

NHC has upgraded Tropical Depression Twelve to Tropical Storm "Leslie" as of 2 pm EDT. It's located over the Atlantic Ocean about 1125 miles east of the Windward Islands, moving toward the west. A turn more to the west-northwest is expected during the next couple of days.
Maximum sustained winds are 40 mph. Leslie could become a hurricane, but is not a threat to land at this time.
Leslie is the second-earliest formation of the 12th named storm in the Atlantic basin, eclipsed only by Luis in 1995.
Leslie is also the eighth named storm during this August, which ties the August record set in 2004.
Get the latest on this storm, including forecasts and graphics, on the NHC website at www.hurricanes.gov




Joeyfl
(Weather Guru)
Thu Aug 30 2012 07:01 PM
Re: Invest 98L Forecast Lounge

Buoy 41041 is now just couple hours away from the center passing overhead. Currently a rapidly falling pressure is being seen (~1008mb) winds out of the NNW . Leslie looks to be getting more and more organized with deep convection firing near the center and impressive banding and outflow features. Would not be surprised to see Leslie a major hurricane at some point in near future with conducive environment ahead of her. Track reasoning is for it to be a fish storm, however thats not a guarantee quite yet as it is plowing along to the west. Models believe it will feel a weakness to the north left behind from Kirk and the trough picking Kirk up however it could potentially miss this pick-up and get caught in an area of weak steering before ridge builds back in. Euro is furthest west with possible impact on Bermuda and New England? We will have to see how it plays out as the post above makes a good point in Kirk being a very small cane and ridge may try to nose back in before Leslie makes a sharp enough turn.

LoisCane
(Veteran Storm Chaser)
Thu Aug 30 2012 10:36 PM
Re: Invest 98L Forecast Lounge

I think it's a little early to say for sure what Leslie will do... she is barely formed and it's just a little early to rely on the 7th day out..

But, we will have a better picture in a few days...

Kirk may be a Hurricane, but he is really small... agreed.


Joeyfl
(Weather Guru)
Fri Aug 31 2012 12:16 AM
Re: Leslie Forecast Lounge

Leslie continues to look better and better with an upper level high pressure cell overhead allowing for excellent outflow in all directions. I see Leslie as a hurricane within next 24 hrs without question and likely major sometime in next few days. Overall the center looks to on a slight north of west movement and looks to be missing forecast points a little to south as the ridge to the north seems to be holding slightly stronger for now.

Ed DunhamAdministrator
(Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017))
Fri Aug 31 2012 05:42 AM
Re: TS Leslie Forecast Lounge

The 31/00Z GFS run does some interesting things with Leslie in the extended forecast. Builds Leslie to a hurricane and stalls it between 25-28N and about 64W for a few days. If this comes close to verifying it will mean an extended period of high waves later in the weekend and early next week in the Bahamas and along the Florida east coast. It then takes Leslie NNE close to the Canadian Maritimes by mid week - which would mean that the Northeast would need to monitor the track for any forecast adjustments to the west.
ED


LoisCane
(Veteran Storm Chaser)
Fri Aug 31 2012 08:30 PM
Re: TS Leslie Forecast Lounge

Good point Ed, very good point.

Everyone focuses on landfall or no landfall. We forget often how storms affect shipping routes and beach erosion, etc.

Either way, there are way too intangibles to say for sure what will be with Leslie a week from now, especially if she becomes the Major Hurricane that models indicate she might be..


Joeyfl
(Weather Guru)
Fri Aug 31 2012 09:17 PM
Re: TS Leslie Forecast Lounge

As many have though Leslie looks to be left behind from the trough/Kirk to its north with it getting caught in an area of light steering winds for few days south of Bermuda. I still do not see any reason why this will not be our first major cane of the season sometime over the next few days. Although I would say that chances of it reaching the U.S are slim I think a track near or west of Bermuda and likely just east of U.S coast looks most reasonable for now. As several troughs are seen coming of U.S through the next ten days thus it would likely feel the pull north/NE sometime in the next beyond 6 day time frame, thus alot of slow and at times random movement is expected between 4-7 days

WeatherNut
(Weather Master)
Sat Sep 01 2012 04:06 PM
Re: TS Leslie Forecast Lounge

It looks today like Leslie's LLC is moving away from the convection to the NW (which follows the NHC forecast points, but the MLC and the convection is moving to the west. Looks like a new LLC might be trying to form there

MichaelA
(Weather Analyst)
Sun Sep 02 2012 08:31 PM
Re: TS Leslie Forecast Lounge

This certainly has been the season of sheared/tilted storms. Leslie's LLC continues to be exposed to the North of the convection this afternoon. With the statistical peak of the season fast approaching, I'm beginning to wonder if this season will produce a major storm at all.

cieldumort
(Moderator)
Tue Sep 04 2012 03:08 PM
Re: TS Leslie Forecast Lounge

Leslie persists as a large, highly-sheared tropical storm, with the models and NHC staying rather bullish on her in the extended period, now taking a significant, and possibly major hurricane right by Bermuda over the coming weekend.

Being that large systems are more difficult to shear out, and that later in the week shear is expected to lessen as Leslie enters what is forecast to be a very favorable upper air environment, it seems reasonable to assume that the consensus (and official) forecast could very well play out.

All that said, the cyclone looks especially challenged this morning, and it is possible that NHC's current intensity estimate of 65 MPH gets throttled back later today or tomorrow.

Further weakening could result in substantial changes to the forecast at 3-5 days out.


GuppieGrouper
(Weather Master)
Wed Sep 05 2012 12:56 AM
Re: TS Leslie Forecast Lounge

Leslie is looking well put together tonight. Has the storm finally stacked vertically? The outflow is not that obvious on the colored infrared satellite. With the forward speed at just 3mph it is showing a potential to increase in intensity. The shear does not seem as great tonight as in the recent past either.

MichaelA
(Weather Analyst)
Wed Sep 05 2012 01:05 AM
Re: TS Leslie Forecast Lounge

The LLC is still on the southern side of the convection, so it is still tilted vertically. The shear is relaxing in the region and with the slow forward movement, Leslie could be getting its act together in the next few days.

GuppieGrouper
(Weather Master)
Wed Sep 05 2012 06:04 PM
Re: TS Leslie Forecast Lounge

It would seem that Leslie is now a 75mph hurricane according to the NHC. So will she get stronger?

MichaelA
(Weather Analyst)
Wed Sep 05 2012 06:25 PM
Re: TS Leslie Forecast Lounge

The NHC forecast is for Leslie to strengthen to very near Cat 3 strength within 3 days as it moves generally northward affecting Bermuda. Looking at the satellite loops this afternoon, Leslie does appear to have strengthened and become vertical with convection now wrapped around the LLC. In the current low shear environment, yes, Leslie will become better organized and strengthen.


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