Major Hurricane Ida

[hlcater]

1 minute ago, Wmsptwx said:

Things seem to have leveled off some.

Nah its still intensifying except thunderstorms in the eyewall have shrouded the eye. It's deceptive.

[MattPetrulli]

 

[WhiteoutWX]

This system has been on the right side of the short term guidance envelope for days. I’m not super surprised.

[jojo762]

That is a pretty devastating "wobble"/multi-hour trend for New Orleans... a mere six hours ago this morning it looked like they might be saved from the eyewall of Ida tomorrow. But now it's looking quite likely that they will take it on the chin. Hopefully we can get some meaningful wobbles in the opposite direction.

[Normandy]

New Orleans is in trouble from a surge perspective no matter where the storm hits because  of the angle of approach and general proximity of the core. The only question is do they get the Cat 3 or greater winds.

[eyewall]

I am really concerned for Houma in terms of core winds. I am starting to get increasingly worried about NOLA 

[WishingForWarmWeather]

I...what. I have no words. Yesterday was "there's no time, shelter in place". 24 hours out, it's this. This is gross incompetence. I can't even grasp this.

 

[sojitodd]

1 minute ago, WishingForWarmWeather said:

I...what. I have no words. Yesterday was "there's no time, shelter in place". 24 hours out, it's this. This is gross incompetence. I can't even grasp this.

 

This makes no sense. The reasoning yesterday was that they could not do it because they could not enact the contra-flow fast enough and they did not want people getting 'caught out in the storm". So this concern has now lessened because we have a full day less to evacuate and the storm is not going to weaken?(it was never forecast to weaken)???

[dseagull]

Just now, Jaguars said:

She’s an absolute disaster 

To repeat history a mere 16 years later is gross negligence.  Good job, mayor. Anything she could do wrong, she has so far. 

[pazzo83]

some folks are posting that traffic is backed up on I-10 from NOLA to freaking Mobile, AL.  Not great.

[Gravity Wave]

3 minutes ago, pazzo83 said:

some folks are posting that traffic is backed up on I-10 from NOLA to freaking Mobile, AL.  Not great.

Looks like it.

[CoastalWx]

So far it quite can’t get the eye to clear out yet. It tries to shoot up hot towers, but can’t wrap around the center.

[Amped]

13 minutes ago, Normandy said:

New Orleans is in trouble from a surge perspective no matter where the storm hits because  of the angle of approach and general proximity of the core. The only question is do they get the Cat 3 or greater winds.

The forecast track  for Ida is far from a worst case scenario for New Orleans.   I think the new Levee system assuming it was built properly can handle the surge.

One good thing about the west track is that winds won't come out of the north and slam lake Pontchartrain into the city.

 

[jojo762]

1 minute ago, Gravity Wave said:

Looks like it.

I rang it up on google maps earlier that it was going to take about 2 hours to go 40 miles from eastern NOLA to just a bit north of Slidel on I-59.

[Radtechwxman]

1 minute ago, CoastalWx said:

So far it quite can’t get the eye to clear out yet. It tries to shoot up hot towers, but can’t wrap around the center.

Yeah I'm a bit perplexed given the environment it's in. I honestly thought it would be exploding right now. Clearly something still holding it back. 

[MillvilleWx]

Ida will be entering the most favorable waters in the Gulf this evening as a pronounced pocket of 87-90F waters are just ahead of its current position. The poleward outflow should continue to be more distinct thanks to the situated ridging to the north. Notice the storm will be entering the most favorable area of min deep layer shear which will lead to convection becoming undisturbed throughout the remainder of the storms life cycle to landfall (Outlined in the black box). 

The favorable time frame will be approaching as well with the diurnal component coinciding with the most favorable synoptics. That's one of the reasons NHC was likely bullish with the call to adjust up to Cat 4 yesterday due to the timing of all the factors coming together, plus an inordinate amount of statistical and numerical guidance showing a favored RI period between 7 PM today and 7 AM tomorrow. No dry air to be found either. All systems should be go for Ida to really take off tonight. I do not like the storm hugging the eastern side of the envelope as this points to higher impacts for NoLA. Hopefully many heed the warnings and get out. 

[Roger Smith]

Isn't the dynamic for Lake Pontchartrain rising water levels from a surge entering from the east? I don't think the northerly wind after Katrina was the real killer for the weakening barriers, it was the rising water levels.

This track could bring surges inland through the swamps and up the Mississippi and also raise Lake Pontchartrain levels but that work done since 2005 might help. 

I think this will play out as worse for wind damage and in some parishes west of NOLA worse for flooding. It may be equal for wind damage along the MS coast, or not quite as bad. At this point I think evacuating west makes a lot more sense than east, as long as you go at least as far as east Texas. 

 

[Normandy]

The absolute worst case is a westward approach where the north eyewall passes over Lake P.  The approach ida is taking is the second worst case.  Strong NE winds will back water up into the lake, and strong south winds bring surge from the south.

[MillvilleWx]

10 minutes ago, sojitodd said:

This makes no sense. The reasoning yesterday was that they could not do it because they could not enact the contra-flow fast enough and they did not want people getting 'caught out in the storm". So this concern has now lessened because we have a full day less to evacuate and the storm is not going to weaken?(it was never forecast to weaken)???

My EM friends said there really was no way to enact a contraflow because it take A LOT of resources and at minimum 2 days to prep for contraflow. Plus, other states are involved in the planning, so this isn't an easy task. Otherwise, I would've been telling people to get out yesterday. They tip toed too much around it. Faster moving system. Need to make a decision ASAP. Also, resources stretched thin due to the Pandemic. It's a logistical nightmare. 

[MillvilleWx]

7 minutes ago, CoastalWx said:

So far it quite can’t get the eye to clear out yet. It tries to shoot up hot towers, but can’t wrap around the center.

It's been trying a while. I think the prime time for the hurricane models has been after 7 PM CDT tonight into tomorrow. Still got time to really get cranking, but it's teetering on the edge of taking off. Once it can clear out, there will be no stopping this buzz saw. 

[sojitodd]

3 minutes ago, MillvilleWx said:

My EM friends said there really was no way to enact a contraflow because it take A LOT of resources and at minimum 2 days to prep for contraflow. Plus, other states are involved in the planning, so this isn't an easy task. Otherwise, I would've been telling people to get out yesterday. They tip toed too much around it. Faster moving system. Need to make a decision ASAP. Also, resources stretched thin due to the Pandemic. It's a logistical nightmare. 

Thanks for the input. One would think that they would be a bit more prepared given last year and the pandemic with the hospitals full there. 

[CoastalWx]

1 minute ago, MillvilleWx said:

It's been trying a while. I think the prime time for the hurricane models has been after 7 PM CDT tonight into tomorrow. Still got time to really get cranking, but it's teetering on the edge of taking off. Once it can clear out, there will be no stopping this buzz saw. 

Yeah I agree, just noting currently. The  outflow looks great and mid level RH looks good for intensifying. 

[MillvilleWx]

1 minute ago, CoastalWx said:

Yeah I agree, just noting currently. The  outflow looks great and mid level RH looks good for intensifying. 

Just can't seem to get over that hurdle yet. Tonight should be interesting to say the least. Quite a picturesque cane for what it is so far. 

[bdgwx]

      ** 2021 ATLANTIC RI INDEX AL092021 IDA        08/28/21  18 UTC **
 (SHIPS-RII PREDICTOR TABLE for 30 KT OR MORE MAXIMUM WIND INCREASE IN NEXT 24-h)
 
     Predictor                  Value   RI Predictor Range  Scaled Value(0-1) % Contribution
 12 HR PERSISTENCE (KT)      :   20.0    -49.5  to   33.0        0.84          14.8
 850-200 MB SHEAR (KT)       :   10.7     30.1  to    2.3        0.70           5.7
 HEAT CONTENT (KJ/CM2)       :   88.0      0.0  to  151.8        0.58           4.3
 STD DEV OF IR BR TEMP       :    8.2     36.6  to    2.8        0.84           7.0
 MAXIMUM WIND (KT)           :   90.0     22.5  to  137.5        0.62           4.2
 BL DRY-AIR FLUX (W/M2)      :  212.2    895.4  to  -55.0        0.72           4.8
 2nd PC OF IR BR TEMP        :    0.3      2.9  to   -2.9        0.45           2.2
 POT = MPI-VMAX (KT)         :   67.3     28.3  to  146.3        0.33           1.0
 D200 (10**7s-1)             :   31.0    -29.7  to  185.9        0.28           0.8
 %area of TPW <45 mm upshear :    0.0    100.0  to    0.0        1.00           0.6
 
 SHIPS Prob RI for 20kt/ 12hr RI threshold=  52% is  10.7 times climatological mean ( 4.9%)
 SHIPS Prob RI for 25kt/ 24hr RI threshold=  56% is   5.2 times climatological mean (10.9%)
 SHIPS Prob RI for 30kt/ 24hr RI threshold=  46% is   6.7 times climatological mean ( 6.8%)
 SHIPS Prob RI for 35kt/ 24hr RI threshold=  39% is  10.0 times climatological mean ( 3.9%)
 SHIPS Prob RI for 40kt/ 24hr RI threshold=  30% is  12.5 times climatological mean ( 2.4%)
 SHIPS Prob RI for 45kt/ 36hr RI threshold=  21% is   4.5 times climatological mean ( 4.6%)
 SHIPS Prob RI for 55kt/ 48hr RI threshold=  12% is   2.6 times climatological mean ( 4.7%)
 SHIPS Prob RI for 65kt/ 72hr RI threshold=   0% is   0.0 times climatological mean ( 5.3%)
    
Matrix of RI probabilities
------------------------------------------------------------------------------
  RI (kt / h)  | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48  |65/72
------------------------------------------------------------------------------
   SHIPS-RII:    52.3%   56.1%   45.6%   39.1%   29.9%   20.6%   12.2%    0.0%
    Logistic:    26.0%   42.2%   32.2%   17.4%    8.8%   12.1%    9.3%    1.2%
    Bayesian:    26.0%   55.7%   25.6%   53.5%   15.3%    5.7%    0.1%    0.0%
   Consensus:    34.8%   51.4%   34.4%   36.7%   18.0%   12.8%    7.2%    0.4%
       DTOPS:    46.0%   21.0%   19.0%   15.0%    2.0%    0.0%    0.0%    0.0%

 

[Amped]

3 minutes ago, WishingForWarmWeather said:

I had always thought/heard that this NW approach, slightly to the left of the mouth, was worst case track scenario for New Orleans. 

Is that not the case? What would be worst case scenario?

Approach from the southeast,  make a sharp 90 degree turn right over the city and exits to the northeast.    

 A track from the south that goes right over the eastern part of the city would be a close second though.

[HKY_WX]

16 minutes ago, Gravity Wave said:

Looks like it.

I think I'd evacuate the other direction

[KPITSnow]

1 hour ago, Alfoman said:

You guys all need to understand that a hurricane's strength is not simply defined by the storm's sustained winds it has but rather the accumulated kinetic energy it holds and how deep its pressure is. Katrina only made landfall as a category 3 but the immense amount of energy it had retained produced storm surge well above that threshold. 

The danger with Ida is having her make landfall while still strengthening as a major rather than producing Katrina-level surge. This will not be Katrina but it can be its own disaster. 

Michael had a pretty horrific surge even though it didn’t really blow up until about a day before landfall.

 

I agree this isn’t Katrina, but I do think there is a bit too much downplaying going on here.

[jacindc]

 

[schoeppeya]

IR presentation is much better over the last hour or two.

[HKY_WX]

No 2 storms are ever the same and that's the beauty of wx/forecasting. Ultimately the next 12 to 18 hours and any RI will prob be what determines if this goes down as one of the greats or overhyped.