CAT 5 Hurricane Dean - Archived threads

[Stormcenter]

I have a feeling Dean may unfortunately be paying a visit to somewhere along
the middle Texas coastline. I just hope his trek over the Yucatan will weaken him significantly.

[mempho]

Check out the latest GR Level 3 radar image. The eye is a cross.

Anyway you could post that? Or at least a link? I'd love to see that.

[Extremeweatherguy]

Next up...the GFDL (in about an hour). It should be very interesting to see what that does. Hopefully this is not the beginning of a model trend back north.

[CrazyC83]

519
URNT15 KNHC 180420
AF302 0504A DEAN HDOB 39 20070818
041030 1420N 06736W 6967 03148 0061 +080 +079 000035 037 036 000 00
041100 1418N 06737W 6965 03150 0055 +085 +077 001033 034 035 000 00
041130 1416N 06737W 6967 03152 0055 +085 +077 000030 031 034 000 00
041200 1414N 06737W 6968 03147 0059 +083 +072 359030 031 031 003 00
041230 1412N 06737W 6965 03152 0062 +081 +074 350032 032 032 005 00
041300 1411N 06738W 6967 03150 0056 +086 +082 345033 033 031 002 00
041330 1409N 06738W 6967 03150 0057 +085 +079 350033 033 031 000 00
041400 1407N 06738W 6967 03154 0058 +085 +074 352033 033 032 000 00
041430 1405N 06739W 6966 03156 0060 +083 +083 358032 033 033 000 00
041500 1403N 06739W 6967 03150 0077 +071 +071 001033 034 033 000 03
041530 1401N 06739W 6968 03154 0096 +059 +059 358032 035 030 007 03
041600 1359N 06738W 6972 03151 0081 +069 +069 345027 030 034 004 03
041630 1357N 06737W 6966 03153 0074 +073 +073 331027 028 999 999 03
041700 1356N 06738W 6967 03152 0071 +076 +076 328028 030 033 004 00
041730 1354N 06739W 6979 03141 0090 +064 +064 331024 025 034 004 00
041800 1353N 06740W 6966 03158 0066 +083 +083 334025 026 034 003 00
041830 1351N 06740W 6968 03160 0081 +073 +073 331028 030 036 005 00
041900 1349N 06741W 6973 03152 0080 +075 +075 334027 028 038 004 00
041930 1347N 06741W 6965 03162 0069 +086 +062 332026 027 036 000 00
042000 1345N 06741W 6968 03161 0072 +086 +050 329027 027 037 000 00
$$

[mgpetre]

Was this sort of swing back and forth typical with storms in 2005? Just curious for comparison. At that time I used NHC and Weather channel as my only sources.

[miamicanes177]

I can see it now. All the little players wanted to take on the big boy. The GFDL came to play. It's not going to be made a fool of on perhaps the biggest storm of 2007. You stick with your bread and butter. If the GFDL is an outlier, then so be it. You go with your ace when the game is on the line. This is game 7 and I want the ball in the GFDL's hand.

[artist]

yes it is - this happens every year. You usually don't see them until a little closer to the storms I think is what happens when you watch them and don't come here.

[fasterdisaster]

Was this sort of swing back and forth typical with storms in 2005? Just curious for comparison. At that time I used NHC and Weather channel as my only sources.

It actually always has been. But unfortunately it's to be expected when we're talking about such a unique force of nature.

[rjgator]

Check out the latest GR Level 3 radar image. The eye is a cross.

Anyway you could post that? Or at least a link? I'd love to see that.

How do I put an image on here?

[Air Force Met]

I can see it now. All the little players wanted to take on the big boy. The GFDL came to play. It's not going to be made a fool of on perhaps the biggest storm of 2007. You stick with your bread and butter. If the GFDL is an outlier, then so be it. You go with your ace when the game is on the line. This is game 7 and I want the ball in the GFDL's hand.

Hey...stick a sock in that kind of talk. The GFDL takes it right into my favorite fishing hole as a Cat 5.

Do you realize how that is going to mess up the flounder run?

[artist]

there is a thread for it under jschiltz (Ithink that's how he spells his name)

[Wthrman13]

Although I've noticed no one is willing to commit to a landfall and no one wants to scare anyone (which I by no means do either), I am going to make my wrong prediction now... despite the fact that without a Houston/Galveston landfall my wife will forever think I'm crazy for worrying about this thing so much, I believe Dean is going to hit the US about 20 miles south of Corpus as a Cat 3. Just my prediction...

Now, while I'm here. Can someone give me a little information as to how much actual data is put into the models? Is it a pressure gradient mostly? Are water vapor synoptics also considered? Is it a glogal model that includes the push from storms on the other side of the world? I know it's the whole "butterfly effect" thing going on to some extent, just curious as to how complete the data models are for these initializations. I was a chemical engineer at one point and know that in a closed system you have to include everything to get any idea as to what's really going to happen and the earth is a fairly closed system (the day we start inputting data about solar flares into hurricane modelling is the day I'll be very confident in the models.) Just curious, because I know very little about the complexities of these things.

All kinds of data goes into the models, but the coverage is nowhere near the total number of grid points (or Fourier components in the case of spectral models) in the model. In other words, the data assimilation problem for initializing the models is a vastly underdetermined problem. So, sophisticated analysis techniques are used to blend the real-world data with a first guess field available at all grid points, which usually comes from a short-range, prior prediction of the model. That said, the kinds of data going into the model are enormously varied these days. Surface weather station observations, upper-air sounding balloons, upper-air profilers, buoys, cloud-drift winds, satellite-derived soundings, and even water vapor fields from a network of GPS sensors are all ingested into the model analyses. It's an amazingly complex procedure, and coming from someone who works with models everyday, it's franky a wonder they do as well as they do, which is really quite well indeed.

Regarding stuff like solar flares, it's generally well-accepted that such things have a very tiny effect on tropospheric weather, not the least because the part of the atmosphere that is being affected most by solar flares contains a very very small fraction of the total mass of the atmosphere. Other sources of error, such as model physics errors are much more significant.

[mgpetre]

Was this sort of swing back and forth typical with storms in 2005? Just curious for comparison. At that time I used NHC and Weather channel as my only sources.

It actually always has been. But unfortunately it's to be expected when we're talking about such a unique force of nature.

Wow, I can see why the folks on here talk about a long week now. Watching 99L was much less stressful. I honestly don't know how I feel anymore. If it were to die out over Jamaica (utter devastation in that case) I would look foolish to many around me for following a storm that doesn't even really effect us, but if the GFDL pans out then I'm just plain scared... I guess this is what Heller called Catch-22. I just hope we all are around two weeks from now.

[Extremeweatherguy]

Was this sort of swing back and forth typical with storms in 2005? Just curious for comparison. At that time I used NHC and Weather channel as my only sources.

At 4-5 days out the models tend to shift around a lot. Once we get into the 3 day and closer range though they usually begin to come into more agreement. That is why we should know so much more by Sunday (3 days out from a possible final landfall) when the models will hopefully be in better agreement.

[ALhurricane]

The GFS initialization of 1004mb is just horrible. There is no way the model can then accurately forecast the motion since the model thinks the cyclone is shallow in nature. This is where you have to give a nod to the GFDL/HWRF in that they can accurately model the depth of the cyclone, in which the motion then relies on a much deeper steering flow.

[fasterdisaster]

The GFS initialization of 1004mb is just horrible. There is no way the model can then accurately forecast the motion since the model thinks the cyclone is shallow in nature. This is where you have to give a nod to the GFDL/HWRF in that they can accurately model the depth of the cyclone, in which the motion then relies on a much deeper steering flow.

Agreed, honestly I think the GFS model is constantly high on something, it's never been all that accurate JIMO.

[cheezyWXguy]

Why has the convection warmed around the top...with the D-max approaching and less dry air intrusions youd think convection would be stronger than it is

[artist]

someone mentioned that it cant's read low pressures very well. I don't know if that is true or not. I wish we did know for sure.

[jacindc]

Is anyone else as surprised as I am to see that TWC is sending Mike Sidell to Jamaica? I hope he's bringing a brick shelter with him.

[mgpetre]

Although I've noticed no one is willing to commit to a landfall and no one wants to scare anyone (which I by no means do either), I am going to make my wrong prediction now... despite the fact that without a Houston/Galveston landfall my wife will forever think I'm crazy for worrying about this thing so much, I believe Dean is going to hit the US about 20 miles south of Corpus as a Cat 3. Just my prediction...

Now, while I'm here. Can someone give me a little information as to how much actual data is put into the models? Is it a pressure gradient mostly? Are water vapor synoptics also considered? Is it a glogal model that includes the push from storms on the other side of the world? I know it's the whole "butterfly effect" thing going on to some extent, just curious as to how complete the data models are for these initializations. I was a chemical engineer at one point and know that in a closed system you have to include everything to get any idea as to what's really going to happen and the earth is a fairly closed system (the day we start inputting data about solar flares into hurricane modelling is the day I'll be very confident in the models.) Just curious, because I know very little about the complexities of these things.

All kinds of data goes into the models, but the coverage is nowhere near the total number of grid points (or Fourier components in the case of spectral models) in the model. In other words, the data assimilation problem for initializing the models is a vastly underdetermined problem. So, sophisticated analysis techniques are used to blend the real-world data with a first guess field available at all grid points, which usually comes from a short-range, prior prediction of the model. That said, the kinds of data going into the model are enormously varied these days. Surface weather station observations, upper-air sounding balloons, upper-air profilers, buoys, cloud-drift winds, satellite-derived soundings, and even water vapor fields from a network of GPS sensors are all ingested into the model analyses. It's an amazingly complex procedure, and coming from someone who works with models everyday, it's franky a wonder they do as well as they do, which is really quite well indeed.

Regarding stuff like solar flares, it's generally well-accepted that such things have a very tiny effect on tropospheric weather, not the least because the part of the atmosphere that is being affected most by solar flares contains a very very small fraction of the total mass of the atmosphere. Other sources of error, such as model physics errors are much more significant.

I guess in that vein of my question I was just saying that at the point that solar flares matter then we have definately gotten the models down to a science. I appreciate the very verbose and informative answer. Are you saying that a certain amount of storm history is put into the model on initialization? I think that would definately be a key to an accurate forecast. What about the question of how far-reaching are the parameters? I see a global model outperforming a localized one for obvious reasons. Again, thank you Wthrman13.