ATL: TROPICAL DEPRESSION ANA (02L)

[KWT]

Yep looks like the shear is increasing a little, may have caught up with the shear that was ahead of it till recently.

Still Ana is an interesting one to study, and I do have a certain amount of worry that this will have conditions to bomb in the Bahamas region, only needs 24-36hrs if its a small system for all hell to break loose.

[Evil Jeremy]

12Z GFDL essentially a repeat of the 06Z run. Its the southern outlier that takes Ana below both Hispaniola and below most of Cuba.

[RL3AO]

P.S. I stand by my comment of yesterday - perhaps the models should have some sort of "El Nino shear bias" built into them, since shear is such a big factor during El Nino events...

But the shear has nothing to do with El Nino. Its being caused by a ULL.

[KWT]

Not impossible EJ if the ridge is strong enough, not likely I grant you but its shorter term motion was heading WSW it appears.

I pray that doesn't happen, though shear levels in El Nino summers tend to be much higher in the Caribbean if thats one small good thjing if GFDL is right.

[RL3AO]

I'm guessing that the models struggle with shear from ULLs because theres a lack of upper air data out there and they can't even see them.

[Aric Dunn]

See no shear on any shear map neither in the mid levels or upper levels but for some reason it has that sheared appearance... lol
well hell there is no real shear pattern to the clouds other then the convection being where it is...
I am pretty sure the dry air pocket to its west is the cause of most of its appearance.. but you cant deny even though no shear maps show shear that there is some from somewhere.. lol

and there is actually pretty decent cirrus outflow to the sw and south and east weird.. lol

under 5 to maybe 10 kts..

[BensonTCwatcher]

WV shows the ULL and cirrus cloud motion to the NW reflects the same. I think it sort of "amplifying" the sat presentation because the NE flow is so dry in the mid and upper levels. The ULL is moving W, but at slower speed than Ana. It's a battle to watch for sure

[KWT]

Its clearly shear, you can see the convection develop then the LLC run away from the convection, looks like to me for once the low level winds are too far fast and the upper levels aren't as quick so the LLC is outracing the convection.

[thetruesms]

See no shear on any shear map neither in the mid levels or upper levels but for some reason it has that sheared appearance... lol
well hell there is no real shear pattern to the clouds other then the convection being where it is...
I am pretty sure the dry air pocket to its west is the cause of most of its appearance.. but you cant deny even though no shear maps show shear that there is some from somewhere.. lol

and there is actually pretty decent cirrus outflow to the sw and south and east weird.. lol

under 5 to maybe 10 kts..

[img]http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8shrZ.GIF[img]

[img]http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8shtZ.GIF[img]

Well, it's just an objective analysis using remotely sensed data, so it's not going to be perfect all the time

[Stormsfury]

Shear compared to last night about 11 pm is actually weaker north of the cyclone than now. Saw a map from CIMSS that had 30kts westerly shear about 5 degrees north and west of ANA.

But still obviously, Ana is undergoing in a westerly sheared environment.

[hurricanefloyd5]

can someone post google earth date for tracking hurricanes pleased like the recon and models and ships and bouys please????

[Evil Jeremy]

So many of the models shifted south this run, aiming now at the northern Caribbean islands. What do all of you think about this? The models are going to keep on shifting, but do you think about this latest model set?

[Weatherfreak000]

I think the possibility of a western track across the ATL near SFL appears to be the highest possible scenario.

(This in response to Eviljeremy)

[caribepr]

That they will keep on shifting until they are over with...

[Ivanhater]

[jinftl]

From Dr. Jeff Masters this pm....

Tropical Storm Ana was born this morning, when the remnants of Tropical Depression Two made a comeback and organized into the first tropical storm of the 2009 Atlantic hurricane season. Ana is the latest first named storm of the season since Hurricane Andrew got its name on August 17, 2009. The two storms have some similarities, as Andrew formed in the same part of the ocean, and also struggled in its early days with high wind shear and dry air. Let's hope the similarities end there.

Ana is struggling this afternoon. After an modest burst of heavy thunderstorm activity prompted NHC to upgrade Ana to a tropical storm early this morning, Ana has run into strong upper-level winds from the west that are creating high wind shear. This shear was not forecast, and it is not clear how long it will last. The shear has acted to drive dry air into the core of Ana, destroying almost all of Ana's heavy thunderstorms. The low-level center of the storm is now exposed to view, something that often foreshadows the death of a storm.

It is possible the shear will destroy Ana, and several models (the GFS and ECMWF) forecast this may be the case. However, the shear forecast calls for shear to drop into the low range, 5 - 10 knots, tonight through Tuesday. If the shear does drop as forecast, Ana should be able to moisten the atmosphere around it sufficiently to protest itself from the dry Saharan air that surrounds it (Figure 1). SSTs are 27°C today, and will increase to 28°C by Sunday. By the time Ana moves into the Bahamas, total ocean heat content rises steeply (Figure 2), and rapid intensification of Ana is possible, if the shear and dry air haven't disrupted the storm. The intensity forecast models, for the most part, predict a steady intensification of Ana to the threshold of hurricane strength five days from now. The HWRF model is on the strong side, predicting a Category 2 hurricane. The GFDL predicts a weak tropical storm five days from now, but that is because the model has Ana passing over the rugged terrain of Hispaniola, something the other models do not predict. In summary, the intensity forecast for Ana has higher than usual uncertainty, and I give equal chances that the storm will be a hurricane--or non-existent--four days from now.

[DESTRUCTION5]

Both GFDL and HWRF take Ana thru the heart of the islands...A sure death..

[Bailey1777]

Hey what happened to accu-weathers the Carribean is closed for business this season?

[Evil Jeremy]

You have to admit Ana is a fighter. She is maintaining nice convection on her eastern side, and if she can keep that up until she escapes the "death zone" and gets a good D-Max, she could become a stronger system than currently forecast. I think we will have a much better idea of where she will end up tracking after she moves out of the death zone.

[brunota2003]

Hmm...seems Ana's LLC is moving WNW now, looking at that visible.