ATL: ANDREA - Post-Tropical

[ozonepete]

For those of you who are looking at the NOAA GOES EAST water vapor satellite to see where the dry air is, please look at this. The dry air appears widespread over most of the western 2/3rds of the GOM on that satellite image but that satellite detects the highest layer of dry air so that if there is dry air at 30,000 feet overlaying moist air below it, it will NOT show the mid-level water vapor. And since it is only mid-level dry air that has a deleterious effect on tropical cyclones, this satellite image is often useless in getting the proper perspective.



Now look at these 2 RUC current and forecast images for 12Z tomorrow morning for RH at 500mb, where it really counts. The entire eastern side of the Gulf is quite moist and forecast to remain so. So you need to use these images, not that water vapor satellite image if you are trying to determine how much dry air will be involved.

RUC 500mb Relative Humidity current


RUC 500mb Relative Humidity forecast for 12Z tomorrow

[boca]

Anybody know why they're not running the tropical models HWRF and GFDL on 91L?

Could it be that its not a depression or storm yet,I think but not sure.

[NDG]

The weird thing is that even with a little better satellite presentation than 24 hrs ago, surface pressures have not fallen at all than 24 hrs ago, but I remember that is what the GFS & ECMWF models showed for today. Tomorrow Wednesday might be a little different story, but the window for strengthening into a TD or TS is closing fast, it has maybe 48 hrs at the most to work with.

[ROCK]

Looks like dry air to me however you want to slice it....

http://www.esl.lsu.edu/static/animation ... v_loop.gif

[blp]

I see an improved presentation on satellite. Banding developing on the S and SE side of the mlc and even some hints of banding in the N to NE side. I think code red 70% late tonight and depression by sunrise.

http://www.ssd.noaa.gov/PS/TROP/floater ... imated.gif

[artist]

For those of you who are looking at the NOAA GOES EAST water vapor satellite to see where the dry air is, please look at this. The dry air appears widespread over most of the western 2/3rds of the GOM on that satellite image but that satellite detects the highest layer of dry air so that if there is dry air at 30,000 feet overlaying moist air below it, it will NOT show the mid-level water vapor. And since it is only mid-level dry air that has a deleterious effect on tropical cyclones, this satellite image is often useless in getting the proper perspective.

http://i189.photobucket.com/albums/z174/philnyc_2007/wv_zps317f00e2.jpg

Now look at these 2 RUC current and forecast images for 12Z tomorrow morning for RH at 500mb, where it really counts. The entire eastern side of the Gulf is quite moist and forecast to remain so. So you need to use these images, not that water vapor satellite image if you are trying to determine how much dry air will be involved.

RUC 500mb Relative Humidity current
http://i189.photobucket.com/albums/z174/philnyc_2007/RAP_255_2013060416_F00_RH_500_MB_zps03db5dda.png

RUC 500mb Relative Humidity forecast for 12Z tomorrow
http://i189.photobucket.com/albums/z174/philnyc_2007/RAP_255_2013060416_F14_RH_500_MBfor2013-06-050600_zpse067ed01.png

thanks for that wonderful explanation ozonepete!

[USTropics]

I also just want to add that with slightly decreasing wind shear, 91L will be able to produce and maintain moisture/convection on the western and northwestern side at a more efficient rate. Also weigh in the fact that an approaching frontal boundary will help create an even more unstable environment, I don't see the dry air as being a major issue. Diurnal maximum should be a telling sign for 91L though. I believe that will be the bridge that allows it to sustain and develop a somewhat decent core.

[Hurricane Andrew]

Really getting more organized.

[NDG]

Looks like dry air to me however you want to slice it....

http://www.esl.lsu.edu/static/animation ... v_loop.gif

And this is the typical cituation for early June GOM storms to fight dry air coming out of MX and the SW US.

[ozonepete]

Looks like dry air to me however you want to slice it....

http://www.esl.lsu.edu/static/animation ... v_loop.gif

Lol. good to see you again Rock! And NDG too.

[ozonepete]

[thanks for that wonderful explanation ozonepete!

Hey Artist, thanks and good to see you again!

[cycloneye]

00z Best Track

AL, 91, 2013060500, , BEST, 0, 233N, 888W, 25, 1008, DB

ftp://ftp.nhc.noaa.gov/atcf/tcweb/inves ... 013.invest

[Evil Jeremy]

IMO 91L is quickly organizing and should be a depression by 11am tomorrow at this rate. Granted it could fall apart overnight but that isn't looking likely

[JonathanBelles]

This is a bit of long read, but here is my post on Eye on Weather for the night:

http://jonathanbelles.wordpress.com/201 ... round-91l/

[Evil Jeremy]

Anybody know why they're not running the tropical models HWRF and GFDL on 91L?

Could it be that its not a depression or storm yet,I think but not sure.

In the past we have gotten those models with invests. Maybe it's sequester related.

[Annie Oakley]

Ahhhh............you have to read this thread as a developing story backed by scientific data and human expertise.

And read Jonathon Belles cause he rocks lol.

[cycloneye]

Ahhhh............you have to read this thread as a developing story backed by scientific data and human expertise.

That is why S2k is one of the best places to be in the net when weather and the tropics are concerned and especially when the hurricane seasons come.

[ronjon]

IMO 91L is quickly organizing and should be a depression by 11am tomorrow at this rate. Granted it could fall apart overnight but that isn't looking likely

Yeah, EJ, been watching it on shortwave SAT and convection really starting to fire around a developing center. With shear forecast to drop to 10 kts tomorrow, and movement over the loop current I can see the NHC upgrading to tropical storm Andrea and skipping TD status status within the next 12-24 hrs.

[jlauderdal]

IMO 91L is quickly organizing and should be a depression by 11am tomorrow at this rate. Granted it could fall apart overnight but that isn't looking likely

The problem is we dont know what is going on at the surface so it may look better on ir that is only part of the story

[artist]

Anybody know why they're not running the tropical models HWRF and GFDL on 91L?

IT took me forever to find anything on the GFDL but here is this page with some runs on it.

http://data1.gfdl.noaa.gov/hurricane/gf ... 1L&prod=QV