Invest 99L:Off E Coast-Discussions

[sponger]

Could be a good wave producer once the lower level circulation gets going. Not a peep on the South Florida stations tonight. Every one will be surprised if they come home from work tomorrow and find a tropical storm on their door step.

[RL3AO]

Well to me...this is clearly a TD and probably a tropical storm. Yes there is a dry upper low sitting to the NNW of the system...but the convective structure is circular and no longer comma-like...phase diagrams suggest it is warm core and t-numbers have been consistent at a 1.5 from TAFB and SAB all day using shear pattern analysis.

I typically don't disagree with the NHC that often but in this case...given how persistent the convection has been I have no idea what they are waiting for except for validation from recon tomorrow.

I suppose the less forecasts you have to write on a stationary system...the better your forecast verification stats are...

MW

Thanks for your input Mike. We all know the NHC is cautious in initiating advisories. Do you think if IR shows convection building over the last know center location that they might initiate advisories at 5am?

[Brent]

Well to me...this is clearly a TD and probably a tropical storm. Yes there is a dry upper low sitting to the NNW of the system...but the convective structure is circular and no longer comma-like...phase diagrams suggest it is warm core and t-numbers have been consistent at a 1.5 from TAFB and SAB all day using shear pattern analysis.

I typically don't disagree with the NHC that often but in this case...given how persistent the convection has been I have no idea what they are waiting for except for validation from recon tomorrow.

I suppose the less forecasts you have to write on a stationary system...the better your forecast verification stats are...

MW

Nice to see you post on this... I'm anxiously awaiting to see the wording in the 10:30 TWO.

[EDR1222]

From the NWS Melbourne office weather discussion this afternoon. Of course these things are subject to change,especially since the system has not even been classifed yet, but right now it looks like a building Atlantic ridge should eventually turn the system to the north.

NWS Melbourne discussion:
STRONG RIDGE BUILDING DOWN THE EAST COAST LATE IN THE WEEK WILL
EVENTUALLY STEER THE LOW NORTHWARD AS THE RIDGE SLIDES INTO THE NORTH
ATLANTIC. CONTINUED DRY WEATHER IN THE WAKE OF THE STORM WILL
PERSIST ACROSS CENTRAL FL THROUGH THE WEEKEND. IT WILL LIKELY NOT BE
UNTIL AT LEAST EARLY NEXT WEEK FOR THE SUBTROPICAL RIDGE TO BECOME
REESTABLISHED ITSELF ACROSS THE STATE. DESPITE SOME DEEPER MOISTURE
MOVING BACK NORTHWARD ACROSS THE AREA...FEEDBACK LOOP (I.E. DRY
AUGUST) SUGGESTS THAT RAIN CHANCES WILL CONTINUE WELL BELOW NORMAL.

[DESTRUCTION5]

Well to me...this is clearly a TD and probably a tropical storm. Yes there is a dry upper low sitting to the NNW of the system...but the convective structure is circular and no longer comma-like...phase diagrams suggest it is warm core and t-numbers have been consistent at a 1.5 from TAFB and SAB all day using shear pattern analysis.

I typically don't disagree with the NHC that often but in this case...given how persistent the convection has been I have no idea what they are waiting for except for validation from recon tomorrow.

I suppose the less forecasts you have to write on a stationary system...the better your forecast verification stats are...

MW

I was thinking the same Mike..Waiting on more model agreement..Which Im seeing now..I bet 1st Advisory will be TS and track wil be east of the US..

[Wthrman13]

Well to me...this is clearly a TD and probably a tropical storm. Yes there is a dry upper low sitting to the NNW of the system...but the convective structure is circular and no longer comma-like...phase diagrams suggest it is warm core and t-numbers have been consistent at a 1.5 from TAFB and SAB all day using shear pattern analysis.

I typically don't disagree with the NHC that often but in this case...given how persistent the convection has been I have no idea what they are waiting for except for validation from recon tomorrow.

I suppose the less forecasts you have to write on a stationary system...the better your forecast verification stats are...

MW

I agree about the circular nature of the convection, which suggests at least that there is potentially a mid-level warm core circulation developing. However, I would argue that the low-level circulation is still tied to baroclinic processes associated with the digging upper-trough (which is actually taking on a negative tilt at its base as we speak; check out the WV floater). I'm not an expert in extra/subtropical transition to tropical cyclones, but I do know that several systems in recent memory have gone through this sort of genesis mechanism before becoming truly tropical. I think once the upper trough closes off over the system and the LLC and the MLC become stacked, so that the warm core has more vertical continuity, then you will see the shear relax and the system become fully tropical. But, that probably will take a day or two more.

EDIT: In fact, the overall evolution of the system up to this point reminds me a great deal of Gustav, which was also designated as a subtropical storm before transitioning to fully tropical and intensifying to a hurricane. I wouldn't be surprised at all to see the same evolution happen here.

[miamicanes177]

This is the most significant United States threat of the 2007 season and the NHC is keeping quiet (only a few sentences in a TWO that not many people read). The NHC needs to issue advisories on TD 7 right now in my opinion. We need a track and intensity forecast from them. There is not too much time to prepare for the east coast. The general public needs to be aware a serious situation could happen this weekend. Please start issuing advisories NHC...

[ConvergenceZone]

Well to me...this is clearly a TD and probably a tropical storm. Yes there is a dry upper low sitting to the NNW of the system...but the convective structure is circular and no longer comma-like...phase diagrams suggest it is warm core and t-numbers have been consistent at a 1.5 from TAFB and SAB all day using shear pattern analysis.

I typically don't disagree with the NHC that often but in this case...given how persistent the convection has been I have no idea what they are waiting for except for validation from recon tomorrow.

I suppose the less forecasts you have to write on a stationary system...the better your forecast verification stats are...

MW

I was thinking the same Mike..Waiting on more model agreement..Which Im seeing now..I bet 1st Advisory will be TS and track wil be east of the US..

I think you are jumping the gun with forecasting a track east of the US, especially since the storm isn't moving much. As a MET(forgot which one) said on here, whether it hits the usa coast or not depends totally on how far east it tracks before it turns and moves west. The less it moves east, the greater a chance of it impacting the east coast. Right now ya have to go with the models since that's all we have, and all but one of the reliable ones point to an east coast landfall.

[BensonTCwatcher]

Yeah Mike I have to admit the convection is looking better http://www.ssd.noaa.gov/goes/flt/t3/loop-ir2.html The low level clouds look like the circ might be finally tightening up. If this keeps up for the next 6 hrs we would probably see an upgrade.

[MWatkins]

Well to me...this is clearly a TD and probably a tropical storm. Yes there is a dry upper low sitting to the NNW of the system...but the convective structure is circular and no longer comma-like...phase diagrams suggest it is warm core and t-numbers have been consistent at a 1.5 from TAFB and SAB all day using shear pattern analysis.

I typically don't disagree with the NHC that often but in this case...given how persistent the convection has been I have no idea what they are waiting for except for validation from recon tomorrow.

I suppose the less forecasts you have to write on a stationary system...the better your forecast verification stats are...

MW

Thanks for your input Mike. We all know the NHC is cautious in initiating advisories. Do you think if IR shows convection building over the last know center location that they might initiate advisories at 5am?

I suppose it's possible. If they hold off tonight then it is hard to imagine them starting advisories at 5AM unless an eye pops out between now and then. Then again...who knows? They wrote off Lilly for one advisory once...remember that?

Also...not much in the way of an upper high yet...but that should change once this starts moving back to the west.

Worth noting that the 0Z SHIPS guidance was initialized using the LGEM model...which is the western-most of the objective guidance...

MW

[RL3AO]

This is the most significant United States threat of the 2007 season and the NHC is keeping quiet (only a few sentences in a TWO that not many people read). The NHC needs to issue advisories on TD 7 right now in my opinion. We need a track and intensity forecast from them. There is not too much time to prepare for the east coast. The general public needs to be aware a serious situation could happen this weekend. Please start issuing advisories NHC...

They issue advisories for tropical depressions and storms, not good looking blobs.

[rjgator]

Seems like the 10:30 TWO has been late a lot lately

[cycloneye]

That is because they have to write the advisorys for Felix and Henriette.Once those are out of the way,the TWO will be released.

['CaneFreak]

Seems like the 10:30 TWO has been late a lot lately

Well, you have to consider they are having to write and FTP advisories and other products as well. We just have to be patient. There is a lot that goes into these products and such.

[Wthrman13]

This is the most significant United States threat of the 2007 season and the NHC is keeping quiet (only a few sentences in a TWO that not many people read). The NHC needs to issue advisories on TD 7 right now in my opinion. We need a track and intensity forecast from them. There is not too much time to prepare for the east coast. The general public needs to be aware a serious situation could happen this weekend. Please start issuing advisories NHC...

They issue advisories for tropical depressions and storms, not good looking blobs.

Ok, I'm going to try to reply to both of you in the same post! Here goes:

While I agree with your sentiment RL3AO, the issue here is not that it is just a convective blob. It clearly has a decent low-level circulation associated with it. The issue is that it's development so far has been almost entirely extratropical in nature, but it is slowly trending more and more tropical (which the NHC has acknowledged in their outlooks).

That's why the NHC has not issued advisories on it yet, miamicanes. It could have hurricane force winds and be hitting the coast, but if it is not tropical in nature, the NHC does not cover it, period. When and if it becomes subtropical and/or tropical, then they will. It's admittedly a judgment call, and they probably discuss it at length before they decide when/if to start initiating advisories in situations like this, but one thing is for certain, they are not sitting on their hands.

[MWatkins]

I have a feeling there have been more than one heated discussion tonight there...if Stacy was there he would have probably intimidated someone to start writing advisories by now (smile)...

MW

[MiamiensisWx]

Seems like the 10:30 TWO has been late a lot lately

I know this post is a one-liner, but your comment prompted me to hastily load the NRL site and refresh every few minutes.

[Roswell_Atup]

it's looking very good now... could leap to TS status...

http://www.nrlmry.navy.mil/tc-bin/tc_ho ... rovap/dmsp

[BensonTCwatcher]

Kinda looks like that trough is curling up (becoming inverted?)

http://www.ssd.noaa.gov/goes/east/nwatl/loop-wv.html

If the steering flow keeps pushing this SE it may end up with an anticyclone over it and then were cooking, from an outflow perspective

easy to see if you go to CIMMS http://cimss.ssec.wisc.edu/tropic2/# turn on the shear display

[Roswell_Atup]

i wonder why the NHC hasn't upgrade it yet...