ATL: TROPICAL LOW ex-FRED (ex-07L)

[cycloneye]

However,NHC does not blink.

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON SEP 21 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER KIMBERLAIN

[LarryWx]

Is it my imagination or does Fred now have a face that is laughing at us?
Heh heh. No matter what else, it's starting to look like a cohesive tropical system on the way up, not down.

I tend to agree. However, what do you make of this, which was just released?


000
ABNT20 KNHC 212337
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON SEP 21 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER KIMBERLAIN

[storms NC]

Well so close to land here again they well not call any thing. Why? Because It really has no time to build up any wind to speak of. Just a rain maker for Parts of Ga, SC and NC and up and put again.

[Blown Away]

However,NHC does not blink.

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON SEP 21 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER KIMBERLAIN

Ex Fred is going to have to earn it's way back to Code Yellow. No matter how good Fred looks at the moment the NHC is not going to upgrade if Fred can't hold convection more than a few hours.

[ozonepete]

Is it my imagination or does Fred now have a face that is laughing at us?
Heh heh. No matter what else, it's starting to look like a cohesive tropical system on the way up, not down.

I tend to agree. However, what do you make of this, which was just released?


000
ABNT20 KNHC 212337
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON SEP 21 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER KIMBERLAIN

They are not going to deal with it until:

1. Measured pressures in the area start dropping noticeably.
2. They can clearly delineate a low level center (LLC) on visible satellite or QuikScat or other microwave satellite.
3. There is persistent convection of a considerable nature (a big blob) over or almost over that LLC.
4. Winds start to pick up (Buoys, QuikScat, ship reporst, etc.)

Like the rest of us, they've been led to believe something was (re)developing too many times. But like the rest of us, I bet they've been enjoying it. We are all learning a lot about fluid dynamics, in this case how a category 3 hurricane can leave behind a little low level center that travels all of the way across the Atlantic that still bears watvhing the whole way. And although they are no longer acknowledging its existence (rightly so), if something does still come of this, they'll call it Fred.

And agreed with Blown_away.

[wxman57]

Careful looking at those IR images and assuming Fred's making a comeback. That convection is several hundred miles southeast of the area of lower pressure. Convection is actually decreasing near the lower pressure.

[ronjon]

Convection refiring again with the LLC still to the NW of the main convection - MLC spinning under the deep convection - do we see a center reformation later tonight? - also, overall convection mass seems to have shifted slightly southward today.

http://www.ssd.noaa.gov/goes/east/watl/loop-ir2.html

[ozonepete]

Careful looking at those IR images and assuming Fred's making a comeback. That convection is several hundred miles southeast of the area of lower pressure. Convection is actually decreasing near the lower pressure.

I agree with you. It will be really difficult to correctly determine what's going on until tomorrow when we can get some visible satellite images.

[Blown Away]

Either a new LLC will develop under the new convection ball or this is a big mess.

[brunota2003]

I'm thinking he is not just a big mess, but a giant one.

[emeraldislencguy]

i agree it is a big mess but I still find it hard to believe that there is no mention of it in the TWO. They have mentioned other times about cloudiness or a cluster of storms--I wonder if ex Fred had never existed and the clooud mass was off the se coast would it had been mentioned in the outlook. Would love some comments on this.

[Emmett_Brown]

The area around 28n 73w is obviously at the mid levels, but the LLC to the NW is so weak and ill defined, I think this blob has a better shot at developing. A look at the IR actually shows some outflow. The overall shape of the system, while small and ragged, is at least symmetrical. As Ozone and others have pointed out, this is sitting over warm water with low level convergence and high level divergence, and lower shear. I give this area a better shot at becoming a TC than the LLC to the NW. Of course, it still has a long way to go, but it is moving slowly, so it has some time.

If low pressure starts to take shape near the MLC, it would not take much for the swirl to the NW to croak. Pressures are high everywhere (heck, the LLC is 1018 mb, which is really high), so spinning up a new LLC should be fairly easy if convection persists... I don't think the the old LLC would hinder the development of a new one.

[Blown Away]

At the moment ex Fred is giving a good cyclonic presentation on the IR, I know it can be misleading, but it looks like a tropical system rate now and I bet in 4 hours my opinion will change.

[ozonepete]

i agree it is a big mess but I still find it hard to believe that there is no mention of it in the TWO. They have mentioned other times about cloudiness or a cluster of storms--I wonder if ex Fred had never existed and the clooud mass was off the se coast would it had been mentioned in the outlook. Would love some comments on this.

It's for the reasons I listed above. They have to analyze it scientifically. Lowest pressure is 1018mb - very high and the LLC is well to the NW of the MLC (although a new LLC may be forming under the MLC). They can't decalre it an area of interest until pressures drop and they can see a significantly tighter LLC swirl and/or either the two centers (LLC and MLC) merge or one takes over, WITH decent convection over it. What we're doing is speculating on what could happen, but we can't prove that any of the factors that I just mentioned are actually occurring. We probably won't be able to measure this effectively until tomorrow.

[ozonepete]

The area around 28n 73w is obviously at the mid levels, but the LLC to the NW is so weak and ill defined, I think this blob has a better shot at developing. A look at the IR actually shows some outflow. The overall shape of the system, while small and ragged, is at least symmetrical. As Ozone and others have pointed out, this is sitting over warm water with low level convergence and high level divergence, and lower shear. I give this area a better shot at becoming a TC than the LLC to the NW. Of course, it still has a long way to go, but it is moving slowly, so it has some time.

If low pressure starts to take shape near the MLC, it would not take much for the swirl to the NW to croak. Pressures are high everywhere (heck, the LLC is 1018 mb, which is really high), so spinning up a new LLC should be fairly easy if convection persists... I don't think the the old LLC would hinder the development of a new one.

Totally agree, Emmett. We have all seen a weak low developing small areas of maximum vorticity (small but tight swirls) that flow around the big ring of the weak low, and then one of these vort maxes takes over and explodes with a lot of convection and becomes the new center. It's part of the theory of how clusters of thunderstorms in the tropics can produce a center with a radius of maximum winds. In this case there appears to be a vort max at the southeast corner of the brtoader low that's staying under most of the convection blowup. If it persists, it could take over as the center. All we can do is watch. No one knows if it will spin up or spin down for the last time. I'm just having fun watching it.

[ozonepete]

At the moment ex Fred is giving a good cyclonic presentation on the IR, I know it can be misleading, but it looks like a tropical system rate now and I bet in 4 hours my opinion will change.

[Blown Away]

i agree it is a big mess but I still find it hard to believe that there is no mention of it in the TWO. They have mentioned other times about cloudiness or a cluster of storms--I wonder if ex Fred had never existed and the clooud mass was off the se coast would it had been mentioned in the outlook. Would love some comments on this.

It's for the reasons I listed above. They have to analyze it scientifically. Lowest pressure is 1018mb - very high and the LLC is well to the NW of the MLC (although a new LLC may be forming under the MLC). They can't decalre it an area of interest until pressures drop and they can see a significantly tighter LLC swirl and/or either the two centers (LLC and MLC) merge or one takes over, WITH decent convection over it. What we're doing is speculating on what could happen, but we can't prove that any of the factors that I just mentioned are actually occurring. We probably won't be able to measure this effectively until tomorrow.

One difference tonight, there is banding to the north of the latest convection ball so I don't think this will be the roach making another appearance. For now it does look like a new circulation center is developing near the convection. Watch the visible loop and you can see weak inflow from the Bahamas into the latest convection ball.

[Emmett_Brown]

The area around 28n 73w is obviously at the mid levels, but the LLC to the NW is so weak and ill defined, I think this blob has a better shot at developing. A look at the IR actually shows some outflow. The overall shape of the system, while small and ragged, is at least symmetrical. As Ozone and others have pointed out, this is sitting over warm water with low level convergence and high level divergence, and lower shear. I give this area a better shot at becoming a TC than the LLC to the NW. Of course, it still has a long way to go, but it is moving slowly, so it has some time.

If low pressure starts to take shape near the MLC, it would not take much for the swirl to the NW to croak. Pressures are high everywhere (heck, the LLC is 1018 mb, which is really high), so spinning up a new LLC should be fairly easy if convection persists... I don't think the the old LLC would hinder the development of a new one.

Totally agree, Emmett. We have all seen a weak low developing small areas of maximum vorticity (small but tight swirls) that flow around the big ring of the weak low, and then one of these vort maxes takes over and explodes with a lot of convection and becomes the new center. It's part of the theory of how clusters of thunderstorms in the tropics can produce a center with a radius of maximum winds. In this case there appears to be a vort max at the southeast corner of the brtoader low that's staying under most of the convection blowup. If it persists, it could take over as the center. All we can do is watch. No one knows if it will spin up or spin down for the last time. I'm just having fun watching it.

Cool. Yup, I see it the same way. You know, to me this system is less Fred, and more of a classic 'Nino type home brew, born off of the end of the front that was interacting with Fred yesterday. Reminds me of storm watching back in the '80s were we had years with an ace of 45 and it felt normal.

[deltadog03]

Pressures are fairly high, but to its credit, there is a big SFC high building down off the NE coast.

[jaxfladude]

I am just about ready to dare TROPICAL LOW ex-FRED (ex-07L) to do it's thing now! I can not take anymore of this