Tropical Depression Bonnie forms 5:15 PM 7/22/2010

[srainhoutx]

18Z Tracks...

[Scott747]

Wanted to share this since it does have include our area as a potential target. LEK has a decent track record with his calls so personally I give his forecast some merit. I questioned him on his timing as I just can't see it impacting coastal Texas that quickly.

With that said it's still quite early in the game and we don't even have a definitive llc yet so any forecast right now is highly subject to wide errors.

http://www.easternuswx.com/bb/index.php ... &p=4990585

[Mr. T]

Yeah, Scott. LEK did great with Alex. I see Chuck is favoring a more westward track as well...

Is that you over on Eastern, Ed?

[Mr. T]

I signed up in 2005 then forgot.

Wx Lizard is probably one of the best usernames I've seen...

You should post more there. Your slanted humor is appreciated

[sleetstorm]

97L has good tropical convection around it. I wonder if its rain will be able to moisten up the atmosphere over and around the island of Hispanola to reduce the aridness?

[srainhoutx]

Should be an interesting night ahead. Thanks to the 'night crew' for keeping those of us that sleep at night informed. I suspect that wxman57 may pop in and drop a post a bit later.

Latest...

[Mr. T]

Are you Flexo over there?

yessir

You see the 18Z NAM is South of Florida and into the Gulf?

Yup

[srainhoutx]

18Z para GFS suggests a further S and W motion the we have seen with that model...

[srainhoutx]

Hour 102 on the para GFS suggests N GOM near LA..



Edit to add 850mb Vort loop...

http://www.nco.ncep.noaa.gov/pmb/nwpara ... loop.shtml

[Mr. T]

The para GFS has a much stronger ridge across the SE compared to the OP GFS.

The para GFS is similar to the Euro, but the Euro contains even higher heights across the South

[wxman57]

Busy day today. Satellite imagery indicates that 97L is well on its way to becoming a depression. Still lacks that well-defined LLC most likely, but I think it may be there when recon arrives tomorrow. Could even be a TS by tomorrow afternoon. After that, I don't see much to hinder continued intensification on Thu/Fri as it approaches S. FL. Could easily be a hurricane by then.

Next question would be about the track. Lots of uncertainty as to the strength of the ridge to the north Fri-Sun. Models have not been consistent in that area. Euro is stronger with the ridge on the 12Z run and the GFS is weaker. Canadian is in between. I don't trust the HWRF as far as I could throw it (yet), and the GFDL doesn't do well with weak systems. Forget the BAMs, as they won't be good in this situation.

I do think that there is a significant hurricane risk to SE FL, including Miami and Palm Beach. Probably not so much north of Vero Beach. It could pass anywhere from the FL Straits near northern Cuba to north of Palm Beach. You folks there better have your hurricane supplies. And then there's the track west of Florida.

I don't have much confidence on how strong the ridge to the north will be by Friday/Saturday. My gut is saying Pensacola as the most likely point of landfall (or maybe I'm just hungry). Realistically, it could strike as far west as Louisiana, though. I'd say the prime area of final landfall would be from New Orleans east to Apalachicola. Odds are good it'll be a hurricane at final landfall. Probably a Cat 1-2 and not a very big one. But all hurricanes are very dangerous.

[biggerbyte]

I stick by my original suggestion. Middle Texas coast, over to western sections of LA. The ridge is simply not going to allow a n. or n. e. Gulf landfall. Now that is of this writing. I reserve the right, as we always need to do, to change my opinion as the next 5 to 6 days progress.

As far as strength... Depends on how far west it can get. This could end up being a big problem for someone. As I stated earlier, this system is a stubborn one, so we might get to throw logic out the door. If that were the case, the sky could be the limit.

[srainhoutx]

Thanks for the update wxman57. If this disturbance shifts further W, do you think it could be a bit larger than what your current thoughts are?

[wxman57]

Thanks for the update wxman57. If this disturbance shifts further W, do you think it could be a bit larger than what your current thoughts are?

Could definitely shift farther west. I'm having "Katrina deja-vu" now. I'm not thinking Texas yet, but am concerned about a Louisiana hit.

As for strength/size, the longer it's offshore, the stronger it could get. Size is hard to forecast. Really big hurricanes typically have some land interaction to break down the core and expand the wind field (Katrina/Wilma), but some don't (Rita). The general scope of the moisture field would suggest an average-sized hurricane, maybe a tad below average. If it gets to be a Cat 3, though, then eyewall replacement cycles could expand the wind field considerably.

[srainhoutx]

Thanks for the update wxman57. If this disturbance shifts further W, do you think it could be a bit larger than what your current thoughts are?

Could definitely shift farther west. I'm having "Katrina deja-vu" now. I'm not thinking Texas yet, but am concerned about a Louisiana hit.

As for strength/size, the longer it's offshore, the stronger it could get. Size is hard to forecast. Really big hurricanes typically have some land interaction to break down the core and expand the wind field (Katrina/Wilma), but some don't (Rita). The general scope of the moisture field would suggest an average-sized hurricane, maybe a tad below average. If it gets to be a Cat 3, though, then eyewall replacement cycles could expand the wind field considerably.

Again thanks. We know you are going to be busy, but try to drop in and let the local folks know what your pulse on this storm is. We know you'll be here if it looks like our troubles.

[Mr. T]

Since everyone else is making pretty forecast graphics, I thought I'd take a shot at it as well just for fun to better show what I've been thinking for a while now...

I'm following the Euro and Euro ensembles closely

flexcast.gif

Basically, I don't think the Great Lakes trough that will be traversing the NE will have too much of an effect on the ridge that the GFS, CMC, and NOGAPS model suite are showing. I like the Euro and UKMET solutions of a continued strong ridge across the South that will eventually track whatever becomes of 97L westward across the Gulf, potentially impacting N Mexico or somewhere in Texas. The seasonal trend for this year has been for models to underestimate upper height fields across the Southern States until a day or two ahead of time. Euro and UKMET performed the best with Alex and TD #2 earlier this season, as they did not cave in on such strong weaknesses developing across the SE from troughs scooting across the North

The storm will likely lose much of its northward heading as it leaves the FL Straights, after the Great Lakes trough moves away and ridging builds back in earnest as we have seen all season long... This is why I think the storm will bend a bit back to the west

Meh, we'll see how this goes

[Andrew]

Thanks for the update wxman57. If this disturbance shifts further W, do you think it could be a bit larger than what your current thoughts are?

Could definitely shift farther west. I'm having "Katrina deja-vu" now. I'm not thinking Texas yet, but am concerned about a Louisiana hit.

As for strength/size, the longer it's offshore, the stronger it could get. Size is hard to forecast. Really big hurricanes typically have some land interaction to break down the core and expand the wind field (Katrina/Wilma), but some don't (Rita). The general scope of the moisture field would suggest an average-sized hurricane, maybe a tad below average. If it gets to be a Cat 3, though, then eyewall replacement cycles could expand the wind field considerably.

That is EXACTLY what I was thinking when I saw the gfs run. I hope the models are not pulling an Ike and shift over to the west as time goes on. One thing that I find very interesting is how this is once again the EURO against all other models. One other thing to remember is last time the GFS didn't do a half bad job on breaking down the high so as always it is important to pay attention to all models.

[Andrew]

Since everyone else is making pretty forecast graphics, I thought I'd take a shot at it as well just for fun to better show what I've been thinking for a while now...

I'm following the Euro and Euro ensembles closely

flexcast.gif

Basically, I don't think the Great Lakes trough that will be traversing the NE will have too much of an effect on the ridge that the GFS, CMC, and NOGAPS model suite are showing. I like the Euro and UKMET solutions of a continued strong ridge across the South that will eventually track whatever becomes of 97L westward across the Gulf, potentially impacting N Mexico or somewhere in Texas. The seasonal trend for this year has been for models to underestimate upper height fields across the Southern States until a day or two ahead of time. Euro and UKMET performed the best with Alex and TD #2 earlier this season, as they did not cave in on such strong weaknesses developing across the SE from troughs scooting across the North

The storm will likely lose much of its northward heading as it leaves the FL Straights, after the Great Lakes trough moves away and ridging builds back in earnest as we have seen all season long... This is why I think the storm will bend a bit back to the west

Meh, we'll see how this goes

That is the other thing that models have a LOT of trouble with. A lot of models usually build the high back way to slowly. Remember how short lived the weakness was for Alex the same thing could happen here, but Mexico may be a tad to far south especially if it does become a hurricane but if it stays weak then that is possible.

[Mr. T]

That is the other thing that models have a LOT of trouble with. A lot of models usually build the high back way to slowly. Remember how short lived the weakness was for Alex the same thing could happen here, but Mexico may be a tad to far south especially if it does become a hurricane but if it stays weak then that is possible.

That is a good point.

I should have mentioned that I really don't think this achieves TS status until just before reaching the FL Straights. It will likely achieve TD status before then, though. Possibly by tommorow evening... The environment around 97L is really not all that favorable for intensification at this time and really won't be around the Florida Straights either. An upper level low just to the west of this system will give 97L bouts of trouble the next coulple of days. However, we're not talking about screaming shear here, and even with light or moderate shear overhead of a system it can still develop. I think we'll see bursts of deep convection for the next couple of days with a defined LLC finally making an appearance as it begins to pass south of FL. This is why I favor such a southerly track initially (weaker system).

If this upper level low, or TUTT, tries to move faster away from this system, then 97L could definitely begin to ramp up in intensity quicker

[Scott747]

Not surprisingly the GFDL and HWRF both shifted W by a fair amount.

Panhandle of Fla. to the NO area.