ATL: INVEST 98L - Discussion

[wxman57]

Any center relocation possible to deeper convection due to the sheared nature of storm?

Not likely. More likely the convection would build south toward the well-defined LLC. Will that happen before it moves inland tonight? Maybe...

[Tireman4]

From Jeff:

Update from Jeff:

Radar and satellite data along the offshore buoys and platforms indicate a surface low pressure system has formed about 150 miles south of Freeport, TX.

Deep convection has developed on the northeast side of the surface low in conjunction with low level speed convergence of an extremely moist air mass. The low is drifting toward the west at less than 10mph and should approach the middle TX coast early Thursday. Upper level winds are out of the SW over the surface system resulting in a shearing of convection off toward the north and northeast. Additionally, dry air in the mid levels is found across much of the central Gulf of Mexico which is limiting deep convection on the SW and S flanks.

Currently NHC is giving the system a 20% chance of development before it crosses the coastline on Thursday morning. A USAF recon. aircraft is scheduled to investigate the system this afternoon to determine if a tropical depression is forming.

With a defined surface circulation having now developed, this will result in some forecast changes.

Rainfall:
NE winds inland on the north side of the circulation are helping to draw drier air over W LA into E TX. PWS range from 1.5 inches north to over 2.0 inches along the coast. This will result in a strong rainfall gradient across the region today and possibly again on Thursday. Expect incoming rain bands along the coast to move inland to roughly US 59 or I-10 today and then fizzle out as they run against the drier air to the north. Rainfall amounts of 1-3 inches will be possible along the coast tapering down to less than .25 of an inch inland (north of HWY 105).

As the surface circulation moves to the middle TX coast on Thursday morning expect deep convection to develop on the N/NE sides of the low and this could be anchored across our S and SW counties from Galveston to Matagorda Bays. Could see some decent rainfall coverage and rates with this activity on Thursday morning, but once again it does not look to push very far inland of the coast…maybe I-10.

The surface low starts to become stretched out into a shear axis along the coast Friday-Saturday and this may be when the best chance of rain materializes for the entire area as deeper moisture is allowed to push further inland.

Winds:
Well defined wind pattern of low pressure over the NW Gulf has developed. NE has increased along the coast with Galveston (NE 16g23 mph) with the buoy 20 E of Galveston (NE 19g 23kts). Wave height at this buoy is 4.0 ft with a wave period of 6 seconds. Apache Platform south of High Island is ENE at 22 g 28kts. Wind profile plots at Galveston North Jetty and Pier 21 indicate a wind speed increase from roughly 12-14kts at 400am this morning to 18-22kts at 700am this morning. Wind direction is also backing from the E to the ENE and NE along the coast currently as would be expected with a develop surface low just to the south. Unless the surface low deepens more than expected should see coastal winds peak in the 20-30mph range today and early Thursday.

Tides:
ENE to NE winds will start to push water toward the coast. Pleasure Pier ran just over 1.0 ft total water level at the high tide this morning and Sabine Pass was a touch higher than that. ENE to NE winds will continue to push water today the coast today into Thursday and Friday with low pressure S and SSW of the upper TX coast producing an onshore flow. Current water levels are running higher than predictions, so not sure how accurate those predictions are looking out of the ET surge guidance using the GFS pressure fields. Appears there was a nice bump in the surge last evening of about .50 of a foot which has pushed the total water levels up and over a foot this morning. Still not expecting any overwash with these levels…really need to get up around 3.5 feet or 4.0 feet for problems to begin. With the 20E GLS buoy showing a 4.0 ft swell with a 6 second period that is not too much wave action heading for the coast…but offshore winds are increasing and swells may get up around 4-6 ft by this evening.

Will update again if needed today per USAF mission (if it happens) or any changes in the organization of the tropical system over the NW Gulf.

[deltadog03]

I will say JB NAILED this....Called it before it even was just a few clouds in the sky. Pattern recognition was spot on.

[Steve]

I got the impression that he was talking about something more significant. He said this week, but you would think it was something yet to come that might be more substantial. I don't have his pay subscription but I did watch the Saturday summary. He might have had something out there prior, but Storm2k was discussing on Friday, so the general public knew of the potential from this site which is better because of all you guys.

[Stormcenter]

98L is not looking well at all. IMO

[stormlover2013]

its not supposed to look well lol, it won't be no more than a depression if that

[davidiowx]

I would be surprised if it were a depression at this point. Though anything can happen with these home brew storms. I just want some good rain for the rest of the week. It might not even give us that though.

[MGC]

Don't looks to be moving much. Just needs some convection near the CC......MGC

[Tireman4]

When is the plane supposed to arrive at 98L?

[baytownwx]

When is the plane supposed to arrive at 98L?

In route, you can follow here

http://www.tropicaltidbits.com/recon/

[Tireman4]

When is the plane supposed to arrive at 98L?

In route, you can follow here

http://www.tropicaltidbits.com/recon/

Thank you.

[underthwx]

Cool recon website..wont be surprised to see a depression designated..my opinion only

[andrewp23]

Levi's site doesn't seem to be updating that often but it seems they've arrived and aren't finding too much...is that correct? It also seems from the Noaa radar the rain is dissipating and breaking up. Can we draw any conclusions from the rain radar?

[davidiowx]

It is very weak. Convection is dying. I don't see any way the NHC classifies this as a TD. Just my opinion though.

[tropicwatch]

Recon did find some west winds

[cycloneye]

Data from an Air Force Reserve Hurricane Hunter aircraft
investigating the weak area of low pressure over the northwestern
Gulf of Mexico indicate that the system does not have a
well-defined circulation. The associated thunderstorm activity has
also diminished some since this morning. However, some limited
development of this system is still possible before it moves inland
over south Texas and northern Mexico on Thursday.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...20 percent.

[Jevo]

Can't do a "he's dead Jim" if he was never alive I guess

[Sanibel]

Another interesting naked surface feature skeleton system in dry air and shear.

[Stormcenter]

poof!!!!!!!!!!!!

[davidiowx]

Looks like some convection trying hard to fire near the center