Major Hurricane Delta

[MSUgulfcoaster]

Eye see you!

[MSUgulfcoaster]

It’s currently moving into an intensification phase, all systems go for the next 12 hours or so

[Orangeburgwx]

Recon shows she is back close to major status

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[Windspeed]

[tiger_deF]

Laura didn't necessarily bust surgewise, but I think that Delta's surge could be significantly higher and over a pretty broad swath of the gulf if the HWRF is to be believed 

[CheeselandSkies]

4 minutes ago, tiger_deF said:

Laura didn't necessarily bust surgewise, but I think that Delta's surge could be significantly higher and over a pretty broad swath of the gulf if the HWRF is to be believed 

So LA gets the big wind and the big surge...just from different storms.

[Amped]

In a good spot to take advantage of the fact the gulf is shaped like a giant comma.

[cptcatz]

Definitely the best looking "eye" of its life so far

[Moderately Unstable]

39 minutes ago, dan11295 said:

Almost none of the 12z intensity guidance makes it a major again. Pressure may drop some before it weakens a bit before landfall, but storm is expanding in size so you will still have a significant surge impacts as you said plus broad area of wind impacts. On radar this will almost certainly have the "half cane" look often associated with north Gulf landfalls. Models have been shown dry air eroding the south side prior to landfall.

Btw, for radars we will have to rely on Houston long range and then Fort Polk as LCH radar is still out. 

Not sure what the state of the repair is right now for LCH, hope the team from OK is able to protect the structure if they have done any work on it already. Intensity guidance has been a bit all over the place with this system. Not bc it's inherently bad, but it's only as good as the data provided. The intensity models don't make it major because they have a low initial intensity. Low end 3 would track with the current intensification and trends. One of the best all time met profs I ever had made a point of telling us, our biggest value was being better than the models. If you as a met can't use your knowledge to deduce when models are right and wrong, you are not adding value to your company (which is your goal, and job, as a met). In other words, being a forecaster is about being better than the computers, and using the computers as tools, not believing they're omnipotent.

26 minutes ago, dan11295 said:

Seems to really be an outlier with regards to intensity. 6z HMON gets down to 950mb with a 960 mb landfall 6z HWRF also gets down to 950mb with 955mb landfall. Realistically only has ~18 hours of favorable conditions left for intensification ~1mb/hr would get you to 950mb but that is probably pushing it as core has yet to fully consolidate.

This is well reasoned good physical thinking. If I start at pressure A and assume the most rapid possible intensification I can think of during the period I expect the storm to be in ideal conditions, what pressure do I get? 939 is definitely an outlier. Perhaps so too are the 12z intensity guidance aids, which seem a hair low, perhaps by 10 knots. 

21 minutes ago, JasonOH said:

Looks like there’s currently 2 hot towers rotating around the center. May get some inner core organization going finally. 

Right on the money I'd say haha. Definitely seeing hints of clearing out in the eye now. I hesitate to say that with certainty because an eye has tried to form a couple of times now and been clouded over quickly but it is looking better eye wise than it has at almost any other point. Looking at the expansion of the estimated 34 kt wind field really speaks to me on the topic I've heard expressed a bit this year of enhancing the way we classify and message for hurricanes. We grade hurricanes based on wind speed. But a giant monster cat 1 that stalls, could be absolutely devastating, and a compact cat 4 that blows in at 15-18mph is certainly going to make folks in the path of the eye have a bad time, but doesn't totally capture the impact, or risk, of the event. For example here with Delta, we have a fast moving storm. The impacts from rain in particular will be much lower, and wind damage at the coast may be lower too because of a combination of speed and pre existing damage. On the other hand, the rapid speed will bring strong wind gusts further inland than a slow moving hurricane. And, all of this doesn't capture the size of the storm. I do think the nws and nhc have done well the last few years by putting out new products like extreme wind warnings, dedicated storm surge warnings etc, to granulize the impacts in a way that goes beyond the number. I still think most members of the public focus most on the cat # though. 

 

MU

[tiger_deF]

Just now, Moderately Unstable said:

 I still think most members of the public focus most on the cat # though. 

Frankly I think that's because hurricanes are pretty complex, and for someone who isn't a weather tracker the nuances of certain aspects of hurricanes are a little much to expect someone to know, especially with the compounding crises already at play this year. The NHC has been doing a good job of distilling the main threats though

[the ghost of leroy]

Looks like another Ike. I’d be careful about extrapolating about strengthening into a major. Could end up just being the beefiest 95kt system. 

[tiger_deF]

[Moderately Unstable]

Just now, tiger_deF said:

Frankly I think that's because hurricanes are pretty complex, and for someone who isn't a weather tracker the nuances of certain aspects of hurricanes are a little much to expect someone to know, especially with the compounding crises already at play this year. The NHC has been doing a good job of distilling the main threats though

Agreed, and I won't continue this topic too much since it gets off topic from Delta itself. The question is: is there a better ranking system. Some in the met community have developed and advocate for an impact based score system that factors in surge, area, speed, rainfall, wind, perhaps more. People may only digest one number, but that number doesn't have to be the sshws. They would adapt to, say, a score between 1 and 30, 30 being worst. Mets could still communicate the wind speed, and even the storm category, and bounce off the impact number to explain the specific risks of the system. Using an impact system can provide more clarity without making things harder for the public. The problem is, you don't want to under warn a cat 4 or 5 because it is small. Nevertheless, most of the risk in hurricanes is the water, not the wind. 

 

MU

[jpeters3]

1 minute ago, the ghost of leroy said:

Looks like another Ike. I’d be careful about extrapolating about strengthening into a major. Could end up just being the beefiest 95kt system. 

I second the Ike comparison.

[Windspeed]

Looks like another Ike. I’d be careful about extrapolating about strengthening into a major. Could end up just being the beefiest 95kt system. 

Ike was dealing with significant ENE'rly mid-level shear as it traversed across the north-central GOM. It wasn't enough to force weakening but after Cuba, Ike also had a large circulation. If you will recall, there was an intense westerly eyeband that could not wrap or stay wrapped for symmetry. The convection remained lopsided but intense enough to keep the large circulation chugging along as a big Category 2. Simply put, the battle between shear and thermal dynamics kept Ike at status quo all the way into landfall. Obviously surge was the issue and led us to a new parameter, IKE.

 

Delta on the other hand should have a good window of much more favorable conditions to actually reattain major status while continuing to expand its convective envelope symmetrically up until moving over cooler SSTs and mid-level shear increases prior to landfall. Granted, the end result may be similar for landfall intensity, but Delta's maximum winds should get higher than Ike's maximum winds ever achieved in the GOM.

 

This all being said, surge is going to be the biggest problem at the coast regardless if it maintains Category 3 or weakens to a 2 by landfall. Expansion and fetch will have already been achieved.

[LakeEffectKing]

If the eye clears in the next 4-6 hours, and the eye radius isn't too large, and with 12-18 hrs. of favorable conditions, Cat 4 is back on the table. before any anticipated weakening.

[tiger_deF]

1 minute ago, LakeEffectKing said:

If the eye clears in the next 4-6 hours, and the eye radius isn't too large, and with 12-18 hrs. of favorable conditions, Cat 4 is back on the table. before any anticipated weakening.

Eye is torching right now, I think it could clear in the next hour

[Radtechwxman]

Definitely best Delta has looked. Even when it was high end cat 4. Eye popping on infrared and visible

[jojo762]

Potential eye of Delta has warmed to ~-40C on IR compared to the ring of <-80C towers around it.

[Windspeed]

Look for an area along the coast to increase in surge height if Delta really gets going by this evening. I think the 7-11 ft could be increased to 12-16 right of the forecasted point of landfall. The 7-11 may be extended further east of that increase as well.

[Windspeed]

Eye is showing signs of warming and the high cirrus are starting to respond with dissipation. You can see the sinking motion. Banding / convective plumes in the eyewall are continuing to go up and they look symmetrical as well. All systems go...

[hawkeye_wx]

For now, the pressure is holding at 968 mb.

[TowsonWeather]

1 minute ago, hawkeye_wx said:

For now, the pressure is holding at 968 mb.

Holding? Wasn't it 970 last advisory?

 

[Wrangler]

At 4:00 a.m.CDT, the Bishkin Model has it tracking a tad to the left, and those steering currents are causing me some concern for a more unpredictable side-step westward, but still within predicted confines.  The mbs will tell the story. 

[Orangeburgwx]

Funky little wind graph for the eye and eyewall

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[shaggy]

13 minutes ago, Windspeed said:

Look for an area along the coast to increase in surge height if Delta really gets going by this evening. I think the 7-11 ft could be increased to 12-16 right of the forecasted point of landfall. The 7-11 may be extended further east of that increase as well.

 

With the decent rate of forward speed hopefully we dont see surges as high as 12 to 16 feet. If this was a slower moving storm that had time to pile the water in then that 12 to 16 feet of surge would be easy.

[BuffaloWeather]

We have an eye

[jojo762]

14 minutes ago, Orangeburgwx said:

Funky little wind graph for the eye and eyewall

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Recon didn’t go straight through the eye like normal, they turned a bit once inside, hence the abnormal readings.

[JasonOH]

Latest VDM still showing open eyewall. Based on IR it looks like there’s a weaker area rotating around that was to the south a couple minutes before the VDM. It’s now on the east side but looks a bit better now.

 

edit: that lasted like 10 minutes

[WhiteoutWX]

Hot towers on the south and east side look to have weakened a lot the last 30 minutes. Now we just have the intense band on the north side of the eye. Eyewall may stay open for a bit longer.