ATL: ZETA - Models

[NDG]

06z Euro shifted to the west, now west of the city of New Orleans over St Charles Parish. Much weaker than previous runs but I see that it was initialized with a pressure in the 990s, might have something to do with it.

[LowerAlabamaTider]

We here in Mobile, even to some extent with Sally, have avoided the worse of storms so many times because of a slight nudge/bump to the east before landfall. Not wishing bad on our neighbors to the west, but kind of hoping that doesn't happen this time around.

[Steve]

One more day, so the models are probably pretty accurate. Looks like next landfall will be somewhere between Grand Isle and the Mouth of the MS River. Depending on whether it's on the east or west side of that spread will determine who gets the worst from Laplace over toward Gulf Shores. Remember, this is liable to be a fairly quick (1/2 day or so) system once the rains set in. NAM 12z is running now. This is where we are with the current modeling and depiction modeling:

HWRF valid 7pm tomorrow:




^^ Note the HWRF shows the most intense convection (around and just after landfall) to be on the north side of the COC

HMON valid 4pm tomorrow (a bit faster than the HWRF)




Early Cycle (GFS) 12z Guidance


Late Cycle (GFS) 06z Guidance


COAMPS Experimental Track (late cycle 6z vs. Official)


EPS Late Cycle (06z) Tracks

[Steve]

NAM 12z valid 5pm tomorrow


3km is still running and not all the way to landfall yet. Give it 5 minutes.

[SconnieCane]

One more day, so the models are probably pretty accurate. Looks like next landfall will be somewhere between Grand Isle and the Mouth of the MS River. Depending on whether it's on the east or west side of that spread will determine who gets the worst from Laplace over toward Gulf Shores. Remember, this is liable to be a fairly quick (1/2 day or so) system once the rains set in. NAM 12z is running now. This is where we are with the current modeling and depiction modeling:

HWRF valid 7pm tomorrow:
https://i.imgur.com/sQZiE6W.png

https://i.imgur.com/68qvmZz.png

^^ Note the HWRF shows the most intense convection (around and just after landfall) to be on the north side of the COC

HMON valid 4pm tomorrow (a bit faster than the HWRF)
https://i.imgur.com/u4ofnlV.png

https://i.imgur.com/qNGOHnJ.gif

Oh my, both show MSLP well down into the 960s.

HWRF sim IR is strictly entertainment at long range, especially with systems that haven't formed yet, but with established systems in short to medium range it has proven pretty darn good.

[Steve]

Agreed.

Here's the 3km NAM 12z




ICON should be next up in an hour or so.

[MississippiWx]

Has anyone noticed the spaghetti models on Tropical Tidbits don’t really matchup with tracks shown on the actual model runs? For example, the spaghetti model shows the GFS track near the Mississippi/AL coastline whereas the actual model run shows the center up near Hattiesburg. Just seems off.

[Steve]

Has anyone noticed the spaghetti models on Tropical Tidbits don’t really matchup with tracks shown on the actual model runs? For example, the spaghetti model shows the GFS track near the Mississippi/AL coastline whereas the actual model run shows the center up near Hattiesburg. Just seems off.

No. I never use their "current storm" link preferring to get those aggregate plots from SFWMD.

[Steve]

Hurricane models are starting to run now. I'm curious to see if HMON and HWRF still landfall a bit SW of New Orleans as landfall point and angle of movement will matter for us here. Fortunately we only have to wait for like the 30-33 hours plots to come in. HMON is already to 27h, so one or two more plots and I'll get that posted.

[Steve]

HMON 5pm tomorrow afternoon @ 974. Landfall looks to be just west of Port Fourchon. HMON shows points north and east of there (Lafourche, St. Charles, Jefferson & Orleans Parishes) should get the bulk of the weather out front of the system.

[SconnieCane]

HMON 5pm tomorrow afternoon @ 974. Landfall looks to be just west of Port Fourchon. HMON shows points north and east of there (Lafourche, St. Charles, Jefferson & Orleans Parishes) should get the bulk of the weather out front of the system.

https://i.imgur.com/agjiIXx.png

Correct me if I'm wrong but that looks like a nasty path to shove water into Lake Ponchartrain.

[Steve]

HMON 5pm tomorrow afternoon @ 974. Landfall looks to be just west of Port Fourchon. HMON shows points north and east of there (Lafourche, St. Charles, Jefferson & Orleans Parishes) should get the bulk of the weather out front of the system.

https://i.imgur.com/agjiIXx.png

Correct me if I'm wrong but that looks like a nasty path to shove water into Lake Ponchartrain.

It is. It's not worst case or anything, but there should be some flow in through Lake Borgne and the Rigolets. Also, the fast movement should deter a lengthy buildup pre-storm.

[Steve]

HWRF is a bit west of the consensus and crosses directly over Lake Pontchartrain




IR Depicted (does not have a landfall/33h plot)

[Steve]

Anyone have the 12z Euro (better than TT) that they're willing to share?

TiA

[Wx_Warrior]

12z EURO

[Steve]

Thanks WxW. That tells me (at 987) to adjust it down about 15mb so maybe 970's and next landfall.

[northjaxpro]

A pretty good consensus that the hurricane models have Zeta going either just west or directly over The Big Easy. Looks more likely they are going to see a fairly good wallop there and the surrounding parishes of Southeast Louisiana and also the Mississippi Coast.

[LarryWx]

Agreed.

Here's the 3km NAM 12z
https://i.imgur.com/ZevzQwT.png

https://i.imgur.com/9nHPQXz.png

ICON should be next up in an hour or so.

I assume you realize that the NAM almost always way overdoes these.

[Steve]

Agreed.

Here's the 3km NAM 12z
https://i.imgur.com/ZevzQwT.png

https://i.imgur.com/9nHPQXz.png

ICON should be next up in an hour or so.

I assume you realize that the NAM almost always way overdoes these.

Of course. It's the only game in town in the 8-9 hour, so I post them when there's a threat. They have been helpful the last few years with pressure falls and occasionally track. But I do appreciate when the 3km breaks the 900mb barrier. 12z's 3km has it landfalling at 960 which probably is a hair low but not completely out of whack with what I expect (970's).

[Shawee]

HMON 5pm tomorrow afternoon @ 974. Landfall looks to be just west of Port Fourchon. HMON shows points north and east of there (Lafourche, St. Charles, Jefferson & Orleans Parishes) should get the bulk of the weather out front of the system.

https://i.imgur.com/agjiIXx.png

Correct me if I'm wrong but that looks like a nasty path to shove water into Lake Ponchartrain.

It is. It's not worst case or anything, but there should be some flow in through Lake Borgne and the Rigolets. Also, the fast movement should deter a lengthy buildup pre-storm.

Agreed. Of much more concern with this angle and path is storm surge flooding in some of the parishes west (south) of the MS river. Slower moving, stronger on this path could cause considerable flooding on the West Bank of St. Charles Parish for instance. Fortunately (hopefully), this one shouldn’t be able to stack enough water into Barataria Bay to overwhelm the main levees/protection system. However there are a lot of homes and camps outside the system. The smaller and faster the better for the West Bank.