ATL: KAREN - Remnants - Discussion

[Dean4Storms]

06z GFS 850mb Vort loop...

http://www.tropicaltidbits.com/analysis/models/gfs/2013100206/gfs_z850_vort_watl.html

[BUCMAN48]

Xironman,

Thats a great point as the IR loop shows the dry air actually moving west
and the area really moistening up.

[TreasureIslandFLGal]

local mets are all over this system. 2 options...weaker into north central gulf, and little if any rain at all for west coast FL penninsula, or else it develops a bit more and will turn towards the northeast with the approaching front and go into the eastern side of the panhandle/near big bend area, and then central and northern west coast FL could then see a lot of rain. won't know until core better develops and strong center more obvious for models to accurately have correct input point.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Sanibel]

Just a better-convected version of the same problems imo. Center still discombobulated.

[xironman]

There was a met on this board years ago, I think Derek, who made the point that there needed to be some shear to advect the dry air into a system to really affect it.

[wxman57]

There was a met on this board years ago, I think Derek, who made the point that there needed to be some shear to advect the dry air into a system to really affect it.

That is true. There will be increasing shear as the system moves northward across the Gulf. I expect a sheared system at landfall with most, if not all, squalls east of the track.

[ROCK]

There was a met on this board years ago, I think Derek, who made the point that there needed to be some shear to advect the dry air into a system to really affect it.

intensity forecasts are pretty weak with this and all models pretty keep it at a 1008-10ish...

[Stormcenter]

It may not not go as far east as earlier thought if the front is slower than previously anticipated. I believe some of the models are now sniffing that out. IMO

[blp]

Just a better-convected version of the same problems imo. Center still discombobulated.

I agree, the vorticity maps continue to show the mid level displaced well to the NE of the low level. Does not look organized yet.

[cycloneye]

This morning's discussion by Dr Jeff Masters:

A tropical disturbance (Invest 97L) over the Western Caribbean is moving to the northwest at 10 mph and is generating heavy rains over the Cayman Islands and Western Cuba. Grand Cayman Island had picked up 2.32" (59 mm) of rain as of 9:30 am EDT on Wednesday. Satellite loops show that 97L has a modest area of heavy thunderstorms that have increased substantially in areal coverage and in intensity since Tuesday, but there is little rotation apparent. Cayman Islands radar also does not show any rotation to the echoes, but there are several prominent low-level bands of heavy rain. The storm has low wind shear of 5 - 10 knots to work with, as well as an upper-air anticyclone aloft that is providing good ventilation above it. Dry air is over the Yucatan Peninsula and Gulf of Mexico, as seen on water vapor satellite loops, and this dry air is slowing development. Ocean temperatures are a very warm 29°C (84°F). An Air Force hurricane hunter flight is scheduled for Wednesday afternoon.


Forecast for 97L: development into at least a tropical depression likely

Wind shear is expected to remain low on Wednesday, then steadily increase to the moderate range on Thursday, then to the high range on Friday, according to the latest SHIPS model forecast. On Wednesday night, 97L will cross the northeastern tip of Mexico's Yucatan Peninsula, bringing 3 - 6" of rain to the peninsula and to Western Cuba. Passage over the Yucatan will act to disrupt the storm. The atmosphere will grow drier as 97L moves northwards over the Gulf of Mexico on Thursday and Friday, and the drier air combined with increasing wind shear will retard development, making rapid intensification unlikely. A trough of low pressure and an associated cold front will be moving through Louisiana on Saturday, and the associated upper-level westerly winds will be able to turn 97L more to the northeast as it approaches the coast on Friday. The GFS model develops 97L into a tropical storm, and predicts landfall will occur along the Florida Panhandle. The European model, which does not develop 97L into a tropical storm, is farther west, taking the storm over Eastern Louisiana. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave 97L 2-day odds of development of 40%, and 5-day odds of 50%. I give a 30% chance 97L will be Tropical Storm Karen with top winds of 40 - 60 mph at landfall between Louisiana and the Florida Panhandle on Saturday, a 5% chance it will be stronger, and a 65% chance it will be a tropical depression or mere tropical disturbance. Heavy rains of 3 - 6" can be expected falling the coast from Louisiana to the Florida Panhandle on Saturday, even if 97L does not develop into a tropical depression.

[blp]

Convergence has been strong for the last 6 hours in an area between the mid and low level vorticities. We might be seeing the low level vorticity shift to that area soon. That would be the ideal place IMO for this to get going and could shoot the gap as well.

[CaneCurious]

There was a met on this board years ago, I think Derek, who made the point that there needed to be some shear to advect the dry air into a system to really affect it.

I think that was Derek Ortt. If my memory is correct he was a meteorology student. Does anyone know where he is?

[Steve]

Derek was working for the Pensacola News Journal for a while and I think moved on from there, but I can't remember where (research team or something??).

As for 97L, I'm not sure everyone fully understands how absolutely lucky North America has been so far this season. This has been a majorly western-biased year with activity, but fortunately nothing has gotten too strong. With the ECMWF depicting some strong ridging off of Canada after the next front, it's a giant blessing this isn't August or September. Anyway, if something does come up, I'd still expect it east of here and won't budge on the remaining requirements to have hit the season perfectly - which is 2 named hits on the USA east of here (MS-NC). Maybe a TD or a bunch of rain ahead for points east (as per similar invests/systems this year). For those of you in Escambia, Santa Rosa, Okaloosa, Walton, Bay, Gulf and Franklin Counties, could there be another 3-5" event? I know I don't have to tell you guys how waterlogged things are there this year. Could be?

This is not official information whatsoever.

[blp]

From the 8am

AN
AIR FORCE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THE
DISTURBANCE THIS AFTERNOON.

What time are they heading out?

[Aric Dunn]

THe center is a little farther to the north than the best track and may end up migrating a little farther depending on the convective development.

[jhpigott]

Near 85W, 20N looks suspect. See some low level turning and new convection firing over the area

http://rammb.cira.colostate.edu/ramsdis ... display=12

[Aric Dunn]

And actually a great microwave pass clearly showing at least a well develop low level circ at 19n 84w ...the surface circ may not be as defined but wont take much more.

[blp]

And actually a great microwave pass clearly showing at least a well develop low level circ at 19n 84w ...the surface circ may not be as defined but wont take much more.


[img]http://www.nrlmry.navy.mil/tcdat/tc13/ATL/97L.INVEST/ssmi/85h/1degreeticks/20131002.0901.f15.x.85h_1deg.97LINVEST.25kts-1008mb-167N-831W.80pc.jpg

Aric and that confirms with the area of greatest convergence for the last six hours I posted earlier. I think an adjusment will be needed to the current position.

[robbielyn]

I see the circulation at 85.1w and 19n

[blp]

If that is the area where this develops it may get stronger than what the models forecast becuase it will certainly be able to shoot the gap and have less land interaction. All the models have this running into the Yucatan at some point.