ATL: TROPICAL DEPRESSION ANA (02L)

[wxman57]

I was looking at that area, and to my eyes, it looks like it is elongated E to W along 13.5 for a few hundred miles; but I dont know a lot about how accurate QSCAT is.

QS can be quite inaccurate, particularly if there is any rain over the circulation. I think the LLC is near that ball of convection, as indicated by at least one observation of NW wind near there.

Well, time to head out for a bike ride.

[srainhoutx]

I was looking at that area, and to my eyes, it looks like it is elongated E to W along 13.5 for a few hundred miles; but I dont know a lot about how accurate QSCAT is.

QS can be quite inaccurate, particularly if there is any rain over the circulation. I think the LLC is near that ball of convection, as indicated by at least one observation of NW wind near there.

Well, time to head out for a bike ride.

Enjoy wxman57. The team will have some activity in the near future it appears.

[ronjon]

One thing to keep in mind is that sea surface temps are pretty marginal north of 13 deg LAT. In fact, at this LAT, they stay that way all the way out to 40W. Models are split into two camps on this one with GFS and BAMs ramping up the strength and sending it NW into the open Atlantic while the Euro, CMC, UKMET, and NOGAPs all keep the system pretty weak and more westward. In fact, the latest run of the Euro has high pressure building in the NE atlantic which pushes a rather weak system toward the west in 7 days. Not sure which way to go now on track since the system seems well organized now but sea surface temps are marginal.

http://www.meteo.psu.edu/~gadomski/ECMWFTROPATL_0z/ecmwfloop.html

[gatorcane]

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

.

Summary from below. Looks like models see a weak 99L that heads west for the next 5 days..seems reasonable to me. I don't think it will ramp up into Ana very quickly given the lack of model support. In fact I don't see a named system anytime soon, perhaps later on this week but I give it about a 25% chance at this point, I probably would keep it a code yellow.

CMC - west towards Leewards as a weak system
GFS - west for the next 3-4 days then a gradual turn to the NW into a weakness in the Central Atlantic
NOGAPs - west for the next few days as a weak system towards the Leewards
ECMWF - west for the next 5 days and a gradual WNW movement to the NE Leewards or just NE of the Leewards
UKMET - west as a weak system for the next several days

[Blown Away]

One thing to keep in mind is that sea surface temps are pretty marginal north of 13 deg LAT. In fact, at this LAT, they stay that way all the way out to 40W. Models are split into two camps on this one with GFS and BAMs ramping up the strength and sending it NW into the open Atlantic while the Euro, CMC, UKMET, and NOGAPs all keep the system pretty weak and more westward. In fact, the latest run of the Euro has high pressure building in the NE atlantic which pushes a rather weak system toward the west in 7 days. Not sure which way to go now on track since the system seems well organized now but sea surface temps are marginal.

http://www.meteo.psu.edu/~gadomski/ECMWFTROPATL_0z/ecmwfloop.html

Correct me if I'm wrong, the CMC & Nogaps bring weaker low into the Caribbean.

[KWT]

Models aren't too agrewssive but then again we've seen countless times the models not doing anything but a system developing anyway.

I think this probably has a pretty reasonable shot at being at least Td2, convection is a little shallow but as has been said SSt's are a little marginal. I doubt it does strengthen too quickly but its looking good IMO, code orange seems more fair then yellow.

[gatorcane]

In this WV loop you can see an upper-level low with weakness heading out to the NW in the upper-left hand corner of the loop and a ridge building SW from near the Canary islands in the upper-right hand corner of that loop. That will keep 99L westbound for the new fews days at its current strength

http://www.ssd.noaa.gov/eumet/eatl/loop-wv.html

[MGC]

I think 99L has a good shot at becoming a TD.....we shall see.......MGC

[gatorcane]

12Z NAM, just NE of Leewards 84 hours:

[cycloneye]

The 12 UTC surface analysis from TAFB has the low moving west.

[Derek Ortt]

thats a different system, I believe

[cycloneye]

The one just east of the Lesser Antilles now.

[cycloneye]

Almost a depression per SSD dvorak T numbers.

09/1330 UTC 14.2N 21.8W T1.5/1.5 99L -- Atlantic

http://www.ssd.noaa.gov/PS/TROP/tdpositions.html

[HURAKAN]

Looking good

[gatorcane]

Cycloneye that is 84 hours out, so I don't think its the one east of the leewards.

[HURAKAN]

A strong tropical wave with a high amount of spin moved off the coast of Africa yesterday, and has a good chance of becoming the first named storm of the 2009 Atlantic hurricane season. The wave was designated 99L by NHC Sunday morning. Wind shear is moderate, about 10 knots, and sea surface temperatures are moderately warm, about 27 - 28°C. There is a large area of dry air to 99L's north, but this is not currently interfering with the storm's organization. This morning's QuikSCAT pass showed a nearly closed surface circulation, stretched out along two axes. The storm can now be classified as tropical depression using the satellite-based Dvorak classification technique, but the surface circulation will have to show better definition before 99L can be classified as a tropical depression. Top winds were in the 20 - 30 mph range, as estimated by QuikSCAT and the Dvorak satellite estimates.

Wind shear is expected to be low, 5 - 10 knots, tonight through Tuesday. SSTs will remain relatively constant at 27°C, so conditions favor development. NHC has given 99L a moderate (30 - 50% chance) of developing into a tropical depression by Tuesday morning, which is a reasonable forecast. The UKMET, GFS, and NOGAPS models all develop 99L into a tropical depression 1 - 4 days from now. The dry air of the Saharan Air Layer may become a problem for 99L 2 -4 days from now, as the storm moves slightly north of due west. It is too early to say if 99L will recurve north of the Lesser Antilles Islands or not, since it will be at least 6 days before the storm makes it that far.

The GFS model predicts development of a new tropical wave coming off the coast of Africa about 6 - 7 days from now.

Jeff Masters: http://www.wunderground.com/blog/JeffMa ... rynum=1274

[cycloneye]

I remember there was a research plane at CV islands in past years.Is that program still working or not?

[gatorcane]

Masters is not willing to forecast a recurve or not yet. I think that makes sense given how far out this system is from impacting the Leewards if it does.

[HURAKAN]

I remember there was a research plane at CV islands in past years.Is that program still working or not?

That plane investigated Debby in 2006. I believed the research was only in 2006.

[KWT]

Well its certainly not 99L either Gatorcane, as Derek said thats another system its picking up.