Tropical Storm Isaac, Part 2: Isaac Moving Into The Gulf Of Mexico-Hurricane Warnings For Morgan City, LA/MS/AL & FL Panhandle To Destin, FL

[turtlehurricane]

They're probably about to make the first intercept of the new core, that fix position isn't too far from it, almost aligned. Pressure looks like it's around 990-991 based on the heights.

[phil882]

And at last, after watching it on radar, it looks like the center relocation has taken place... so the system is now markedly further NW of the forecast track.

[Superstorm93]

And at last, after watching it on radar, it looks like the center relocation has taken place... so the system is now markedly further NW of the forecast track.

More organized, but less time to strengthen?

[phil882]

More organized, but less time to strengthen?

The further northwest position probably does cut down the landfall time somewhat. This new center still has no well organized inner wind core, so I don't think this changes the poor prospects for short term intensity change right now.

[Superstorm93]

If this is just west of the new convective burst, than this could be close to forming an eye.

BR/ZDR

[turtlehurricane]

70 mph flight level winds in the NE quad which isn't the most intense quadrant. This could be Hurricane Isaac.

[rcad1]

Hunters actually place the center to the se of the deepest convection with a pressure of 991 mb

[jcwxguy]

Hunters actually place the center to the se of the deepest convection with a pressure of 991 mb

the Dropsonde has 990

[phil882]

70 mph flight level winds in the NE quad which isn't the most intense quadrant. This could be Hurricane Isaac.

SFMR only supports around 45-50 knots with those flight level winds. While winds might be more impressive in the NW quadrant due to the convection, typically the NE quadrant has the highest winds in a NW moving storm.

Hunters actually place the center to the se of the deepest convection with a pressure of 991 mb

990 with a 10 knot wind... so probably looking at 989 hPa with the adjustment of 1 hPa per 10 knots of wind. Its better organized than earlier tonight for sure, but the convection being focused on the NW side still indicates the system is experiencing southerly shear.

[wxmeddler]

Sonde with 990mb with 10 kt winds from the SE. Also of note, 25°C at 850mb.

[Superstorm93]

This might belong in the banter thread, but Palm Beach Airport just reported a 61 mph wind gust.

Isaac has a very impressive wind field.

[Minnesota Meso]

70 mph flight level winds in the NE quad which isn't the most intense quadrant. This could be Hurricane Isaac.

Sorry to ask you this question in this thread, but I have been following your post, if it goes to Hurricane force winds, do you have a guess ( that all I ask now, not a forecast) as to how strong it will be approaching the coast? Never mind landfall.

[thewxmann]

hmmm.. maybe not. Upper low looks to be weakening with a strong southwesterly flow into the Isaac. If the upper low continues south maybe some of that southwesterly shear will become turn more easterly...

The GFS upper level forecasts imply this will not take place until very close to landfall, actually. I wouldn't be surprised if this remained at Cat 1 status until 12-24 hours prior to landfall before the shear eases up.

[turtlehurricane]

SFMR only supports around 45-50 knots with those flight level winds. While winds might be more impressive in the NW quadrant due to the convection, typically the NE quadrant has the highest winds in a NW moving storm.

990 with a 10 knot wind... so probably looking at 989 hPa with the adjustment of 1 hPa per 10 knots of wind. Its better organized than earlier tonight for sure, but the convection being focused on the NW side still indicates the system is experiencing southerly shear.

Winds are so weak at the sfc in the NE quadrant since it is the furthest quadrant from the convection, winds can easily be 10-15 kt higher at flight level and the sfc in the NW quadrant imo.

[deltadog03]

I also measure a 300-315 at like 15mph *or right around there*

[Superstorm93]

Very impressive amount of lightning in the core of the convection.

Recon needs to inspect this area to see if there are stronger winds.

[turtlehurricane]

I also measure a 300-315 at like 15mph *or right around there*

I've been tracking the radar center since it split off and have 312 °, it is about 520 miles from the coast if it went in a straight line so probably a little longer considering its going to curve north... so about 36 hours from the coast at 15 mph and it's supposed to slow down a little. That would put it onshore Wednesday after 1 pm. This relocation definitely cut landfall time short a bit.

[Superstorm93]

56kft tops just west of the LLC.

Hail marker also showing up. Must be some nasty GR in there.

[phil882]

Winds are so weak at the sfc in the NE quadrant since it is the furthest quadrant from the convection, winds can easily be 10-15 kt higher at flight level and the sfc in the NW quadrant imo.

We'll see. It does look like higher reflectivity is trying to wrap around the west quadrant of the system in the last few radar cycles.

[Dsnowx53]

The Euro made quite a shift to the west, and stalls JUST to the east of New Orleans for like 12 consecutive hours.

[dan88]

Recon's out of there for now, next one leaves in 40 minutes and expected to get to the core shortly before the 5am advisory.

[valkhorn]

Recon's out of there for now, next one leaves in 40 minutes and expected to get to the core shortly before the 5am advisory.

It looks to me like they tried to find the old center, had a lot of conflicting data, then intercepted the convection and found a ton of wind but by the time they got to Sanibel Island they waited for a confirmation and were probably tired and low on fuel so they decided to head back for the next crew to look at the blob of convection.

[LovintheWhiteFluff]

I don't think this is a surprise, but the Euro has moved to the west once again, NOLA. Not good. So far one of the best preforming Minor models has been the HWRF, I truly hope the intensity forecast is wrong.

HWRF tends to overdue the intensities.

[Superstorm93]

00z HWRF is in a really bad spot now...

[phil882]

The ECMWF is substantially weaker with the final intensity of Isaac... on the order of 20+ hPa on this run.

[wxmeddler]

The ECMWF is substantially weaker with the final intensity of Isaac... on the order of 20+ hPa on this run.

I was out today, so I didn't see the 12z run but the wunderground site has it at 968 just off shore of Bay St. Louis.

[jcwxguy]

has it at 952 at hr 60 (up to 960 by landfall)

[phil882]

I was out today, so I didn't see the 12z run but the wunderground site has it at 968 just off shore of Bay St. Louis.

It was in the 940 hPa range on the 12z run. The two primarily reasons for the weaker intensity are further west postion initially, and the upper level low over the W GOM taking slightly longer to get out of the way, so it imparts south to southeasterly shear on Isaac for another 12-18 hours or so.

[Superstorm93]

Whole 6z suite is weaker.

[Dsnowx53]

I zoomed in more on wunderground, and it shows 952mb at 60 hours about 45 miles east of New Orleans. It pretty much stalls.

Edit: I see someone beat me to it.