Invest Thread

[RisingStar]

What would be the limits of this storm if it were to become a hurricane? From looking at historic storms in that area, it seems that maybe a maximum of category 2 is likely.

Also, Does anyone know a link for recent sea temperatures to the East of the US?

[kold weather]

Given it'll go over the gulf stream IF the shear compeltely eases off it could probably get upto cat-3. Sea temps in the W.Atlantic are generaly running about 1C above average.

The strongest east coast hurricane that formed in a similar way appears to be Diana in 1984 which became a cat-4 at 135mph. I think the shear will probably be there in some limited form for a while yet and dry air is still a little issue, though not nearly as much as yesterday. Also maybe the other factor that may limit it reaching a sstrong as it can go in theory is simply it may make landfall before it maxes out.

however I'd rather wait for the ssytem to beocme a TD/TS before making any calls about strength.

[Iceberg]

99L is now a tropical T2.

07/1445 UTC 29.5N 69.6W T2.0/2.0 99L

07/1145 UTC 29.0N 68.8W T1.0/1.0 99L

07/0645 UTC 28.4N 69.8W ST1.5/1.5 99L

[kold weather]

Recon should be taking off shortly, I dare say it'll find a strong TD and maybe even a tropical storm, esp given a tightening pressure gradient due to a developing high to the north and also due to the large convective complex just tothe east of the center.

Note also what a great feeder band the system has right now, as the southern side is pretty void of deep convection you can really see where the invest's inflow is!

Nice amount of convection on the eastern and north side trying to wrap round the center, if it can do that then it may get going pretty quickly, a sits got all the basics already present in regards to a fairly strong LLC and decent convection, just a matter of time now I think before we see something of note. Still looks like a possible SC/NC landfall as well, though that also is going to be tight as to whether it actually makes landfall or not. I'll make a more detailed post tomorrow morning.

A 2.0 is pretty close to tropical storm strength, its going to be interesting to see what recon finds, whether its a TD or a TS...i'll be very surprised if we don't have a classified system before midnight.

Edited September 7, 2007 by kold weather

[RisingStar]

It appears that there isn't going to be any further developments as the tropical depression/storm hasn't formed as expected.

[Somerset Squall]

It appears that there isn't going to be any further developments as the tropical depression/storm hasn't formed as expected.

NHC begs to differ:

SPECIAL TROPICAL DISTURBANCE STATEMENT

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

505 PM EDT FRI SEP 07 2007

THE AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING THE

LOW PRESSURE SYSTEM BETWEEN BERMUDA AND THE SOUTHEAST U.S. COAST

HAS NOT YET IDENTIFIED A WELL-DEFINED CLOSED SURFACE CIRCULATION.

THE AIRCRAFT WILL CONTINUE TO INVESTIGATE THIS SYSTEM...AND IT

COULD BECOME A TROPICAL OR SUBTROPICAL CYCLONE AT ANY TIME AS IT

MOVES WEST-NORTHWESTWARD AT ABOUT 10 MPH. INTERESTS ALONG THE

SOUTHEAST AND MID-ATLANTIC COAST OF THE U.S. SHOULD CLOSELY MONITOR

THE PROGRESS OF THIS SYSTEM...AND TROPICAL STORM WATCHES COULD BE

ISSUED THIS EVENING.

$$

FORECASTER KNABB

[RisingStar]

:lol: I Didn't mean to sound like I was ruling out a TS altogether, I was just expecting to hear of a new named storm from the latest recon mission, but yes it seems that development could still happen in the next 48h or so.

[tinybill]

has GABRIELLE got uk name stamped on it later on !!!!

http://forecast.mssl.ucl.ac.uk/shadow/trac...namic/main.html

[Gray-Wolf]

A nice 'wave front' pouring off west Africa over the last 18hrs. I wonder if this will bulldoze it's way across the Atlantic or will it be squished by conditions mid-Atlantic?

[Iceberg]

90: has rather unexpectedly been named , still lots of uncertainties but a US hit is possible, Ships does strengthen a bit, boarderline CAT 1.

DISTURBANCE INVEST (AL902007) 20070909 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

070909 0000 070909 1200 070910 0000 070910 1200

LAT LON LAT LON LAT LON LAT LON

BAMS 23.5N 86.5W 24.1N 88.2W 24.8N 90.0W 25.7N 92.1W

BAMD 23.5N 86.5W 23.5N 87.8W 23.8N 89.5W 24.3N 91.3W

BAMM 23.5N 86.5W 23.9N 88.0W 24.3N 89.8W 24.9N 91.8W

LBAR 23.5N 86.5W 23.6N 87.6W 24.4N 89.0W 25.2N 90.6W

SHIP 20KTS 24KTS 30KTS 35KTS

DSHP 20KTS 24KTS 30KTS 35KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

070911 0000 070912 0000 070913 0000 070914 0000

LAT LON LAT LON LAT LON LAT LON

BAMS 26.4N 93.9W 27.3N 96.4W 27.6N 97.7W 28.5N 99.1W

BAMD 24.9N 93.3W 25.9N 96.2W 27.3N 97.1W 31.2N 93.2W

BAMM 25.7N 93.7W 26.7N 96.4W 27.7N 97.1W 29.8N 96.1W

LBAR 26.4N 92.0W 29.2N 93.4W 33.1N 90.1W 39.8N 79.5W

SHIP 41KTS 55KTS 61KTS 61KTS

DSHP 41KTS 55KTS 61KTS 32KTS

[kold weather]

Invest 90L is a real mess right now, it does seem to have maybe some midlevel rotation though its hardly strong I suppose thats why it has been given the invest title. Convection is all over the place and the system is being sheared and in truth unless that shear weakens this isn't going to become anything.

Mind you if uit does head towards Texas like some of the models show, even an open wave could cause problems given the amount of rainfall some parts of Texas have had recently. This may well be playing into the minds of the people who declared it 90L. 91L and 92L aren't far off IMO in the Atlantic.

[mettalfabrik]

from the OPC showing forecast track of TS gabrielle

[Iceberg]

Another update because 91L has been named out in the Atlantic.

Attached pic shows the 3 areas of concern.

Gabrielle is really going to be extra-tropical very soon an interesting litle feature, but it failed due to over shear.

90L is still very unorganised, some potential there for a TS hit on Texas and things still need watching.

91L is another ITCZ path etc attached,. there will be a window of development for this system. Dry air won't really be an issue. A much earlier re-curve due to the ridge weakness is there, SHIPS the overcooker of the tropical world takes this to a hurricane again, certainly one to watch but nothing will happen in the near time frame.

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

070909 1200 070910 0000 070910 1200 070911 0000

LAT LON LAT LON LAT LON LAT LON

BAMS 10.0N 33.0W 10.4N 34.6W 10.7N 36.0W 11.1N 37.2W

BAMD 10.0N 33.0W 10.4N 35.1W 10.7N 37.2W 10.8N 39.1W

BAMM 10.0N 33.0W 10.4N 34.9W 10.6N 36.7W 10.9N 38.3W

LBAR 10.0N 33.0W 10.5N 35.4W 10.9N 38.3W 11.5N 41.1W

SHIP 20KTS 26KTS 33KTS 41KTS

DSHP 20KTS 26KTS 33KTS 41KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

070911 1200 070912 1200 070913 1200 070914 1200

LAT LON LAT LON LAT LON LAT LON

BAMS 11.7N 38.1W 13.6N 39.5W 16.3N 42.2W 19.1N 46.4W

BAMD 10.9N 40.9W 11.1N 44.0W 11.6N 46.5W 11.9N 48.5W

BAMM 11.1N 39.8W 12.1N 42.1W 13.5N 43.4W 14.7N 45.1W

LBAR 11.9N 43.9W 12.8N 49.2W 13.5N 52.9W 13.5N 55.0W

SHIP 51KTS 66KTS 72KTS 75KTS

DSHP 51KTS 66KTS 72KTS 75KTS

[Gray-Wolf]

91L looks very much like the front of the wave I noted rolling off Africa 24hrs ago. The water vap. loop showed quite a 'tall' wave (plenty of amplitude) as it rolled into the Atlantic. The following wave isn't as amplified but did look 'busy' as it too slipped into the Atlantic.

[kold weather]

Well we now have 3 invests in the Atlantic.

Firstly we have Invest 90L. This one won't take long as i doubt there'll be any development with it, shear is just too strong and while ther eis moderate convection firing and some hints of rotation i don't really think its al lthat likely to form to be honest, if it does it'll be a weak TS at most bringing a lot of rainfall to places that probably don't need much more, like N.Mexico and Texas.

91L is a very long away from making any land threat and also pretty far east. It reminds me somewhat of Dean in terms of where its developing. With Dean there was a uber strong ridge to its north. With 91L there is weaknesses present ion the ridge which may allow for 91L to gain more lattiude and also the key question is whether or other system, 92L creates any weakness, as the two will very likely follow each other in the long term. Short term only slow development is likely as it has a very broad circulation with it which always takes longer to get going so this probably won't be a notable tropical cyclone for the next 24-48hrs IMO but its a runner down the road. No models have run on this yet however so no real good indicator of its exact track. I think probably this will also be a hurricane eventually but I won't comment on how strong till i feel more confident about track.

92L is the short term worrying system that needs to really be watched IMO. Its convection is already pretty well organised and we could well see a tropical depression out of this pretty soon IMO. As long a sshear can stay down (always a big IF!) then in the region its heading towards I see few reasons why this can't become a hurricane. Track is, like 91L, hard to say as none of the global models forecast it to develop and tropical models haven't been run by the Bam's, however the entire east coast of US and maybe the Bahamas as well needs to watch this system very closely. Early Bams show a thread to Florida and the Bahamas as being the greatest and interesting take the wave upto 91kts, mid cat-2 strength which is entirely possible, if not higher is the set-up allows, heat content, esp over the Gulf stream would support cat-4. Shear should be low thanks to a close by upper high and no dry air to note is present.

In terms of its structure there appears to be some circulation present with it though the obs don't really suggest a LLC just yet but it may not take long as it has got an obvious cyclonic curl with it. Could easily be a TD in the next 24hrs at the current rate of organisation.

So in conclusion, very busy Atlantic, will probably have two named storms next week to watch, one probably very long tracker and both possible landfalling threats...the tropics are heating up!!

(ps, graywolf---Invest 91L, the E.Atlantic system came off Africa about 48hrs but it is the system you think it is, just it came off a little longer then you think.)

Edited September 9, 2007 by kold weather

[Iceberg]

Invest 92L has looked good for a little while, but thought I was seeing something in nothing.

Some evidence of outflow and rotation on quikscat. Ships takes this to 80Kt and a florida hit.

Well worth looking at tomorrow morning.

[Gray-Wolf]

91L still pumping up lots of towers and now it's rolling into warmer waters. I really reckon that this one is worth a watch (Three Cat5 landfalls anyone?)

[Iceberg]

92L is looking pretty subdued.

90L is still got as much action as a dead rabbit.

91L is looking quite fiesty GW, both GFDL and HDWF take this to a hurricane, with the latter really taking it forward see attached. IT could get it's self together maybe tomorrow to give a TD then a quick TS.

Both models look to weaken the ridge too much though and so take it further north. At this time an estimated landfall would be SCarolina, NCarolina.

[kold weather]

90L is still not exactly looking like its going to develop.

92L is currently completely stripped of its convection at the moment though a pretty strong MLC still remains. as we saw with Ts 'Gabby' when features keep a strong circulation at whatever level there is always a chance it can regroup as soon as condtions get better again.

For now 91L is obviously the main feature to focus on as it continues to look pretty good. SHIPS start this at 20kts, which based on quikscat is probably fair to assume. Convection is pretty solid but very spread out, suggests this system wil lbecome a beefy large system.

However i don't think this is gonig to rapidly develop, because its large size and fairly broad circulation suggests a slow get togtherh over the next few days, probably won't become a TD before 24hrs from now, and TS will likely take another 24-36hrs on top of that. Still this does look a possible developer in the long run and will be a long tracker.

91L track is still tough to call as it all depends on how much latitude it gains as it heads towards the weakness. The GFDL/GFS are very unrealistic stalling the system for 24hrs late tomorrow then turning it NW over the next 72hrs. The system probably will gain some latitude but not nearly so much as is suggested currently and indeed the models slowing the system down to turn NW is going to make the track probably rather wrong. The weakness will lift the system up somewhat but to what extent its hard to say. It is quite deep right now, around 10N at 37W according to quikscat but it does have probably 5 days to avoid the lesser Antilles, but who knows!

After 72hrs a new ridge should come across and send 91L back on a W/WNW track and therefore i think ther eis a very high chance this system will landfall somewhere, anywhere from the Caribbean upto the east coast of the USA should be watching, its a fair way away from those further north/west but probably only 4-5 days away the lesser Antilles.

As for strength, this is when i usually curse these systems. I'll just say that on the normal proviso it probably has a good chance of becoming something noteable, how noteable depends on the systems exact track and where it goes, as heat content differs a lot from region to region. IF it develops though a hurricane is probable.

[Iceberg]

Slow improvement of 91L, it's path has shifted a bit south, but now GFDL and HWDF both take him to a medium strength hurricane. HWDF down to 940 and nearly 100Kts.

90L is looking a little better this afternoon (little meaning little). Could hit as a TS for Texas, it's a slow mover so has a bit of time.

[Gray-Wolf]

I was just thinking that the G.O.M. looked a tad busy today. Lets see what a bit of sunshine will do to it all. There's a Mexican blob, Texan Blob and a Floridean blob all growing at quite a pace. No rotation in any of them as I can gauge it.

[Blackie]

I was just thinking that the G.O.M. looked a tad busy today. Lets see what a bit of sunshine will do to it all. There's a Mexican blob, Texan Blob and a Floridean blob all growing at quite a pace. No rotation in any of them as I can gauge it.

Love the technical terms, GW. Now those I do understand!

They sound more like drinks, though. I think I sank a few Floridean Blobs in Billy Bob's bar in Dallas. Whatever they were they went down a storm.

[Gray-Wolf]

What I take to be 91L (burst of convection at 42west) has just popped it's toes into 28c waters and seems to like it.Following on behind (32west) is also starting to bubble nicely.

The 'Texas Blob' seems to be stalled offshore but ,to me, shows no further signs of developing into anything more than a line of strong storms.

[Somerset Squall]

What I take to be 91L (burst of convection at 42west) has just popped it's toes into 28c waters and seems to like it.Following on behind (32west) is also starting to bubble nicely.

The 'Texas Blob' seems to be stalled offshore but ,to me, shows no further signs of developing into anything more than a line of strong storms.

The "Texas Blob" is the only one the NHC seem to think may develop- conditions are favourable but like you, I don't really think it'll develop much.

A BROAD LOW PRESSURE AREA THAT IS CENTERED ABOUT 100 MILES EAST OF

THE LOWER TEXAS COAST IS PRODUCING DISORGANIZED SHOWERS AND

THUNDERSTORMS. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR SOME

DEVELOPMENT OF THIS SYSTEM AS IT DRIFTS SLOWLY WESTWARD OVER THE

NEXT DAY OR TWO.

[Iceberg]

I am waiting for the post eclipse images to come in but Invest 91L looks to be getting it's act together finally Quikscat shows a closed circulation down the the ground with the precip centre, good evidence of rotation, some of the convection deep(which is what you would expect at this time of the day !). Dvorak is upped to 1.5 and ships has upped it's intensity initialisation from 20Kt to 25Kt. If things look OK still in around an hours time, this should become a TD in the next 24 hours.

90L has lost it's convection again. Without the ability to keep convection firing for 24hrs this will not develop.