ATL: GABRIELLE - Remnants - Discussion

[psyclone]

One thing that we do have is persistent convection. it may have a chance once it clears the eastern Caribbean graveyard by late week. it still has "that look" and the calendar (despite the dearth of activity thus far) tells us to pay attention. I remain intrigued and would not be at all surprised if the NHC gradually lifts development potential over the coming days.

[Hurricane Alexis]

Obs across Barbados, the southern Antilles and Tobago indicate an elongated (but present) LLC. I've been looking at upper-level flow projections of the GFS, Canadian and Euro and all are predicting a deepening trof across the Gulf of Mexico in 4-5 days, with moderate to strong WSW-W flow aloft across the southern Gulf. If those projections are correct, then I would expect that if it develops it will track toward Jamaica or a little north of there then turn north or NNE across Cuba. Possible threat to south Florida, but could turn north to the east of Florida.

Guess it's that time of the year here in south florida.

[hurricanes1234]

The models have this as a potentially major hurricane, let's see if this holds true. The next name on the list is Gabrielle, and if it devastates land, it would probably be the 2013 version of Hurricane Sandy and Hurricane Irene. To me, nearly all storms moving through this area have impacts on land. Let's hope everyone stays safe.

Personal Forecast Disclaimer: The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[blp]

Obs across Barbados, the southern Antilles and Tobago indicate an elongated (but present) LLC. I've been looking at upper-level flow projections of the GFS, Canadian and Euro and all are predicting a deepening trof across the Gulf of Mexico in 4-5 days, with moderate to strong WSW-W flow aloft across the southern Gulf. If those projections are correct, then I would expect that if it develops it will track toward Jamaica or a little north of there then turn north or NNE across Cuba. Possible threat to south Florida, but could turn north to the east of Florida.

Hello Wxman57, thanks for your input, it is always appreciated. Where would you put the percentage of this developing?

[perk]

Obs across Barbados, the southern Antilles and Tobago indicate an elongated (but present) LLC. I've been looking at upper-level flow projections of the GFS, Canadian and Euro and all are predicting a deepening trof across the Gulf of Mexico in 4-5 days, with moderate to strong WSW-W flow aloft across the southern Gulf. If those projections are correct, then I would expect that if it develops it will track toward Jamaica or a little north of there then turn north or NNE across Cuba. Possible threat to south Florida, but could turn north to the east of Florida.

thanks it's nice to be able to rule this one out of my neck of the woods.

[HurricaneDREW92]

Obs across Barbados, the southern Antilles and Tobago indicate an elongated (but present) LLC. I've been looking at upper-level flow projections of the GFS, Canadian and Euro and all are predicting a deepening trof across the Gulf of Mexico in 4-5 days, with moderate to strong WSW-W flow aloft across the southern Gulf. If those projections are correct, then I would expect that if it develops it will track toward Jamaica or a little north of there then turn north or NNE across Cuba. Possible threat to south Florida, but could turn north to the east of Florida.

thanks it's nice to be able to rule this one out of my neck of the woods.

Not a met but Texas is not ruled out. It ain't over till its over

[Craters]

Until the ULL ceases to induce WSW shear over 97L, the upper level vorticity will continue to be stretched out. You can clearly see that's what is occurring currently:

http://i.imgur.com/NmtaWOr.gif

However, there remains strong low level vorticity and the mid level has improved somewhat over the past 6-9 hours. Still has a ways to go, and the western Caribbean will provide a better environment with a lot of heat potential and piled up air to work with.[

Hi, Everybody --

USTropics' post brings up a topic that's kind of related to 97L at the moment: When does "shear" end and "ventilation" begin? I understand that you have to have some pretty decent convection underway to have to worry about ventilating the system, and there undoubtedly are shades of gray between the two. Given those qualifying statements, though, is there some sort of rule of thumb that's used to discriminate between shear and ventilation? As the ULL pulls away, will its shear on 97L become helpful ventilation, for instance? Or is 97L not organized enough to require ventilation yet?

Thanks!

[weatherwindow]

Thanks Cycloneye....my stomach was looking like that model map ^ there for the past 3 days but should be ready for part of the recon mission Tuesday if they go.

Good morning Dave...Happy Labor Day weekend...can you provide the link to track to Global Hawk missions...Thanks, Grtz from KW, Rich

Thanks, Luis

[cycloneye]

Thanks Cycloneye....my stomach was looking like that model map ^ there for the past 3 days but should be ready for part of the recon mission Tuesday if they go.

Good morning Dave...Happy Labor Day weekend...can you provide the link to track to Global Hawk missions...Thanks, Grtz from KW, Rich

Here is link to the tracker.

http://airbornescience.nasa.gov/tracker/

[ScottNAtlanta]

Until the ULL ceases to induce WSW shear over 97L, the upper level vorticity will continue to be stretched out. You can clearly see that's what is occurring currently:

http://i.imgur.com/NmtaWOr.gif

However, there remains strong low level vorticity and the mid level has improved somewhat over the past 6-9 hours. Still has a ways to go, and the western Caribbean will provide a better environment with a lot of heat potential and piled up air to work with.[

Hi, Everybody --

USTropics' post brings up a topic that's kind of related to 97L at the moment: When does "shear" end and "ventilation" begin? I understand that you have to have some pretty decent convection underway to have to worry about ventilating the system, and there undoubtedly are shades of gray between the two. Given those qualifying statements, though, is there some sort of rule of thumb that's used to discriminate between shear and ventilation? As the ULL pulls away, will its shear on 97L become helpful ventilation, for instance? Or is 97L not organized enough to require ventilation yet?

Thanks!

If you saw the winds blowing the convection in the same direction...thats shear. If its just the northern part such as we have here, its ventilation. Thats a very simple version. Shear as an excuse is vastly over used in the media

[galaxy401]

One thing that we do have is persistent convection. it may have a chance once it clears the eastern Caribbean graveyard by late week. it still has "that look" and the calendar (despite the dearth of activity thus far) tells us to pay attention. I remain intrigued and would not be at all surprised if the NHC gradually lifts development potential over the coming days.

Agreed. The eastern Caribbean is known for killing weak storms. However since it's September, it'll be hard to go against climatology at this point.

[ScottNAtlanta]

Martinique Radar

http://www.meteo.fr/temps/domtom/antill ... SAIC2.html

[TropicalAnalystwx13]

Invest 97L has continued to become better organized since last night. Observations from the Lesser Antilles show that the broad but closed low-level center the NOAA Gulfstream aircraft found yesterday afternoon has become more intense, with a 16kt west wind on Barbados earlier today. The low-level circulation remains very broad however, stretching into the eastern Caribbean Sea. Until this consolidates, we're unlikely to see this become designated. And unfortunately for the system, it's about to enter the eastern Caribbean Sea where the accelerated trade wind flow reduces surface convergence and promotes sinking air. Because of this, I doubt we see any development until it reaches Hispaniola's longitude or farther west. The upper-air environment looks favorable throughout the entire period.

Of note, the LGEM brings the system up to 103 knots in 120 hours. Too bullish as to be expected with something that hasn't developed yet, but it shows the possibilities in the western Caribbean. Just something to watch for now.

[tolakram]

Jeff Masters http://www.wunderground.com/blog/JeffMasters/article.html?entrynum=2507

Forecast for 97L
Wind shear is expected to be in the low to moderate range for the next five days, and ocean temperatures will be warm, 28 - 29°C. The disturbance is steadily moistening the atmosphere and is moving into a moister environment, so dry air will be less of an impediment to development as the week progresses. The main factor keeping the disturbance from developing over the next two days would appear to be the fact that 97L is quite large, and is stretched out from east to west over a wide expanse. Large, elongated systems like 97L usually take several days to consolidate and spin up. Another factor that will likely retard development is the presence of strong surface trade winds over the Eastern Caribbean ahead of 97L, south of the Dominican Republic. These strong trade winds are a common feature of the Eastern Caribbean, and make the region something of a hurricane graveyard. As the surface wind flow to the west of 97L accelerates into this wind max, air will be sucked from aloft downward towards the surface, creating sinking air, interfering with the formation of thunderstorm updrafts. The best chance for development of 97L would appear to be on Wednesday or Thursday, when the disturbance reaches the Central Caribbean. The wave will likely spread heavy rains to Puerto Rico, the Virgin Islands, and the Dominican Republic by Tuesday, and to Haiti by Wednesday. These rains will be capable of causing life-threatening flash flooding and mudslides in mountainous regions in Puerto Rico and Hispaniola. Of our three reliable models for predicting genesis, the UKMET, GFS, and European models, only the UKMET model develops the disturbance, predicting it will become a tropical depression south of Haiti on Wednesday, and near Jamaica on Thursday. In their 8 am EDT Sunday Tropical Weather Outlook, NHC boosted the 5-day odds of formation of 97L to 30%, and the 2-day odds to 20%.

[tolakram]

Live view at zoom 2 range: http://wwwghcc.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-E%20HURRICANE&lat=15&lon=-61&info=vis&zoom=2&width=1000&height=800&type=Animation&quality=95&palette=ir1.pal&numframes=5

Look at the blowup in convection over Lake Maracaibo on the north coast of South America.

[Fego]

GFS has been right on 97L's track but still doesn't develop it. Hard to understand that after viewing the invest growing in convection.

[HurricaneDREW92]

Think we'll see 20/40 at the 2pm TWO or even 30/40. Seems reasonable with it consolidating a bit as well as the fact its heading into the W Carribean.

[SouthDadeFish]

Here is a microwave pass from earlier today, around 12Z:



From what I'm seeing on visible satellite, it appears that it really is trying to get its act together. West winds on the south side of the circulation look to be strengthening.

[SouthDadeFish]

Yup, Barbados is reporting west winds at 23 mph... Could be starting to be tighten up.

[gatorcane]

Yup, Barbados is reporting west winds at 23 mph... Could be starting to be tighten up.

Could be, it is looking better on Satellite by the hour. I would think NHC ups the % chance of development in the next Outlook.

But we have seen plenty of nice looking areas of convection this year so far only for them to collapse so maybe NHC will to wait until the next advisory to see if there is persistence before making any changes.