INVEST 99L near Leewards,comments,sat pics,etc #4

[shortwave]

Just a quik question for anyone who may be able to answer. in this wv loop, the feature just to the north of the wave digging down a bit is? Ull?
http://www.ssd.noaa.gov/goes/east/catl/loop-wv.html

[senorpepr]

Yeah. Here is a tip. Water colored markers and a q-tip and bleach! that way when you mess it up...you can erase!

I love streamlining. Not sure when you went through, but they actually took one of my maps and put them into the "how to" binder. It was one of the WPAC basin maps. Pretty cool.

Wonderful tip!

I enjoy streamlining and it's a life saver for the tropics!

I went through the course May-June of this year. I remember those WPAC basin maps. For the three typhoons we had to forecast for, I was rather proud that I led the class with the lowest track error. (FWIW, we only had to forecast two days out.)

[Air Force Met]

OK, silly question here:

What is a cusp and how can you discern it in Sats?

It's real hard on satellite unless you know what you are looking for. You have to look at the cloud elements. It takes a lot of practice.

A CUSP is an area of sharp cyclonic turning where a trof axis is. ON a streamline analysis chart it is depicted as one line (blue...divergence) meeting another line (red...convergent) in the middle of a cyclonically curved line to the south of them and an much more cyclonically curved line to the north of them. Both ends of these lines meet at the ends of the blue and red line.

Go here:

http://wx.erau.edu/reference/text/Anal-TW_01Feb00.pdf

and an image is on page 67.

[PTrackerLA]

If the convection holds overnight and the "cusp" finally closes off I see no reason to believe we won't have a TD on our hands either late tonight or tomorrow morning.

[wxmann_91]

Thank you AFM for the explanation and link.

I'll post your response in the Question Box since I posted the question in there too.

[benny]

Bouy 41100 - 20:00 GMT

pressure 1011.8mb

wind NW at < 2 knots

I think those are TSTM winds. The vort center, from the GHCC still image, appears to be near 16.1/58.1. The buoy is at 15.9/57.9.

So the buou should have some SE winds right now....but it is under a TSTM and has NW winds...so I think that is most likely what it is...and as we saw earlier...there was no no real veering of the winds as it approached.

Yeah - steady ENE winds until this last report.

I'm not arguing with you, AFM!

Interesting to see the pressure down below 1012mb though. I wasn't sure we were going to see that.

Highly unlikely that those NW winds are due to a tstm since all the tstms are on the east side.. outflows would tend to shoot away from the system, not toward the center of it. This looks like the outer part of the wannabe cyclone circulation to me. Unfortunately it is hard with a small fast-moving system to see much veering with hourly reports. If it is still westerly next hour.. i will be very interested though as it seems to have gotten its act together in a big way today.

I'm not a big fan of streamlines as they tend to not be particularly useful unless you have a lot of data and don't have to make up the streamlines.. ie like this system with a few observations.

[Thunder44]

OK, silly question here:

What is a cusp and how can you discern it in Sats?

It's real hard on satellite unless you know what you are looking for. You have to look at the cloud elements. It takes a lot of practice.

A CUSP is an area of sharp cyclonic turning where a trof axis is. ON a streamline analysis chart it is depicted as one line (blue...divergence) meeting another line (red...convergent) in the middle of a cyclonically curved line to the south of them and an much more cyclonically curved line to the north of them. Both ends of these lines meet at the ends of the blue and red line.

Go here:

http://wx.erau.edu/reference/text/Anal-TW_01Feb00.pdf

and an image is on page 67.

Thanks for the great link, AFM. I'm going to be looking through that booklet in the next few weeks or so.

[Derek Ortt]

Cangialosi and I were just debating whether or not this is a surface low.

I still cannot close this thing off; thus, IMO, it should not be classified as a low

[Swimdude]

This is causing more hype than 98L! I think it's time for an avatar! Hehehe

[HurricaneHunter914]

Does 99L have an LLC?

[Grease Monkey]

Does 99L have an LLC?

If not yet. Very Very Very close and yes this required 3x "verys"

[skysummit]

Does 99L have an LLC?

According to the pros here....no, not yet. But in my opinion, it's real close.

[AJC3]

Cangialosi and I were just debating whether or not this is a surface low.

I still cannot close this thing off; thus, IMO, it should not be classified as a low

Did he get to meet the Prez today?

[Air Force Met]

Highly unlikely that those NW winds are due to a tstm since all the tstms are on the east side.. outflows would tend to shoot away from the system, not toward the center of it. This looks like the outer part of the wannabe cyclone circulation to me. Unfortunately it is hard with a small fast-moving system to see much veering with hourly reports. If it is still westerly next hour.. i will be very interested though as it seems to have gotten its act together in a big way today.

I'm not a big fan of streamlines as they tend to not be particularly useful unless you have a lot of data and don't have to make up the streamlines.. ie like this system with a few observations.

Well...there is a big TSTM just to the north of the buoy and the vort center is to the NW of the buoy. Go to the GHCC and see for yourself. Since the vrt center is NW of the TSTMS are east...then that means they are over the buoy. Right? Either way...when there are TSTMS in the area and the windfield is light...it contaminates the flow.

As far as streamlines go and you not being a fan of them...that means you have never been a forecater in an area with limited data...plain and simple. For one thing...there are plenty of cloud elements to analyze the cusp...which is how this is being analyzed...not on the basis of a couple of buoys. Second, streamline analysis is bread and butter for forecasters in the tropics with limited data. You don't have to have actual hard data points from buoys or ships to do a streamline chart. When I was in central america...I used sfc data+model data to prepare my streamlines...and only model data to produce my upper level streamlines (250mb)...since there was very little upper air data. If you don't use streamlines in the tropics to help you forecast...you are sunk.

And you will bust your forecast. That is the hard core facts...which is the reason so many new forecasters have a hard time forecasting in the tropics. You don't have a lot of data...and that is EXACTLY where streamlines come in. You don't need ships...you can use satellite and model data to offset that gap...if you know what you are doing.

[Derek Ortt]

not sure. I didn't get to NHC today until almost 3 p.m. for the Bob Hart seminar, and I only talked to him about AMS business for about 5 minutes after the seminar

[benny]

Cangialosi and I were just debating whether or not this is a surface low.

I still cannot close this thing off; thus, IMO, it should not be classified as a low

Why not? You have a well-defined pressure minimum... and winds.. albeit light.. from all points of the compass within the last 24 hours.. I've seen NW, SSW, SE, NE... close enough! Do you really think that just a few scattered buoy obs are going to be enough to close off a system? When does a pressure minimum become a low? There isn't anything that says it has to be closed.. that is NHC Tropical Cyclone definition, but says nothing about any area of low pressure.

[bvigal]

Wow! I just spent 20 minutes wading through all these posts to try and figure out what is going on!

Here, let me put it this way: You live where I do, and you own a boat which is how you make your living, plus it is your home. What odds does everyone here give you that in less than in 36 hrs you are going to be slammed with 50kt-wind tropical storm??? 1%, 5%, 10%, higher? Forget the U.S. mainland and cat 5 hurricanes for one second, just how much organizing is it going to do before reaching 64W?

[Derek Ortt]

I use the definition of a low-pressure center to include a closed circulation. That is what I refer to as a low center

[skysummit]

So.....a "CLLC".

[AJC3]

Wow! I just spent 20 minutes wading through all these posts to try and figure out what is going on!

Here, let me put it this way: You live where I do, and you own a boat which is how you make your living, plus it is your home. What odds does everyone here give you that in less than in 36 hrs you are going to be slammed with 50kt-wind tropical storm??? 1%, 5%, 10%, higher? Forget the U.S. mainland and cat 5 hurricanes for one second, just how much organizing is it going to do before reaching 64W?

I think it will probably get pretty squally there in the VI tomorrow. What's SJU forecasting for y'all?