2021 Atlantic Hurricane season

[Ed, snow and hurricane fan]

3 hours ago, Prospero said:

Something to keep an eye on for the next few days.

The proverbial squashed spider.

[Ed, snow and hurricane fan]

CPC's EWP (empirical) MJO changes slightly, but has remained fairly consistent last 2 weeks, the Atlantic becomes favorable after the first week of August.  5 day running mean, you can see it is coming, although the unfavorable phase won't end immediately.  Not an MJO master, spaghetti in various phases, unless well clustered, I don't even try.  It seems useful in relatively neutral ENSOs.  I follow Paul Roundy's students on social media, I don't know the science of CCKWs and the such, but it is useful.  I assume empirical has the same meaning as in engineering, equations derived from best fit data, not theoretically derived.  Or empirical predictions that have been fairly stable should be fairly accurate.

[Ed, snow and hurricane fan]

1990s, in Excel, you could put in observed lab or field data, several variables, guessing their relative weight or relation (squared, cubes, log) with coefficients, and make it best fit the data and determine the coefficients.  r^2 suggested if one had relative importance wrong.

 

I'm sure one can still do that today in Excel, but I have no idea how I did it.

[LoboLeader1]

90L looking meh this afternoon.

[Ed, snow and hurricane fan]

48 minutes ago, LoboLeader1 said:

90L looking meh this afternoon.

A very elliptical LLC with only the Southeastern edge near convection is not a TC, in my opinion, but NHC not cancelling the flight tells me their current development odds probably reflect the chances of an upgrade in a bit over an hour.

[Prospero]

2 hours ago, Ed, snow and hurricane fan said:

I'm sure one can still do that today in Excel, but I have no idea how I did it.

As a programmer, Excel is an amazing application. I get paid for esoteric stuff very few people can do, but it is interesting to me how much time I spend in Excel doing what the people who pay me could do if they knew how.

Export whatever data you see in a .CSV file, and Google how to manipulate it in Excel.

[Prospero]

1 hour ago, LoboLeader1 said:

90L looking meh this afternoon.

Didn't you know, "Meh" is the 2021 theme? That is almost a requirement so far for a storm to develop. LOL

[Prospero]

Forgive me for "Storm OCD", but seeing a LLC on visible is exciting. Can actually see the circulation even though everything is far away. Better than watching a mid or upper level convection burst that is exciting as well, but "misplaced".

Waiting to find out what they find.

Yea, so many potentials that die, but come on, it's been BORING for a while and we could use some rain here.

[cptcatz]

Recon found a definite center with a small pressure drop right in the middle, but without convection overhead it's not gonna be named. 

[Prospero]

14 minutes ago, cptcatz said:

Recon found a definite center with a small pressure drop right in the middle, but without convection overhead it's not gonna be named. 

What?? This is 2021!!

Did Elsa ever have convention all the way over it??

OK, seriously a "small pressure drop" if enough to keep me obsessing...

[Prospero]

Rain please?

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Sat Jul 24 2021

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Earlier this afternoon and evening, an Air Force Reserve Hurricane 
Hunter aircraft investigated the low pressure system off the east 
coast of Florida and found a well-defined center of circulation 
about 185 miles east of Cape Canaveral.  However, the system still 
lacks organized shower and thunderstorm activity near its center 
and therefore has not met the criteria to be designated as a 
tropical depression.  Environmental conditions are expected to 
remain marginally conducive for additional development, and a 
tropical depression could still form overnight or on Sunday while 
the low moves generally westward at 5 to 10 mph toward the east 
coast of Florida.  Interests in Florida should continue to monitor 
the progress of this system.  Another Hurricane Hunter aircraft is 
scheduled to investigate the system Sunday morning, if necessary.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

Forecaster Berg/Blake

[Prospero]

Look a convection burst! (OK, bed time for me, I get up early as hell. But I'll look when I get up!)

[Ed, snow and hurricane fan]

4 hours ago, Prospero said:

Look a convection burst! (OK, bed time for me, I get up early as hell. But I'll look when I get up!)

4 hours later, less convection, no GEFS support (based on pressure, although mean precip totals suggests some ensembles see something very weak bringing some rain tracking West through Florida and then dying over the Central Gulf)  Not *quite* McCoy time, but close.  Euro Op and some ensembles suggest something weak, not directly linked to 90L, tries but fails to organize in the Eastern Gulf, that *might* be the GEFS mean precip, not 90L.  Either way, looking slow.  

[cptcatz]

90L has fizzled but there's an impressive burst of convection north of Hispaniola.

[cptcatz]

Some very faint signals on the GFS, GEFS, and Euro for something to form in the MDR around August 4-7. Not much but more than what we've seen in the past few weeks. 

[FLweather]

Looking at visible.. at least 2 small vortices left off shore. That will continue to disapate

 

But the mid level vortex is pushing in with the associated dry seabreeze.

Aiming directly at Volusia county. Around Titusville.

Pretty stout NE to Sw flow on radar in the lower levels.

Even with the seabreeze it's hard to get convection to fire up over the FL with a stiff NE flow.

On to the next one .

 

 

[GaWx]

 This one, Invest 90L, could turn out to be the 4th tropical system to impact this area and it is still July! If there's going to be impact here, this is how I like them, weak!

[gtg947h]

12 minutes ago, GaWx said:

 If there's going to be impact here, this is how I like them, weak!

Agreed. Getting tired of the rain though...

[GaWx]

36 minutes ago, gtg947h said:

Agreed. Getting tired of the rain though...

 

  I've gotten ~8.50" MTD, which is double the normal, with about half from Elsa. No lawn irrigation needed anytime soon. Western Chatham, including KSAV, has gotten a good bit less though still ample amounts. Some areas of especially Skidaway Island have gotten over 10" MTD!

 The rainfall is protecting us and much of GA and the SC Lowcountry nicely from any heatwaves for at least now. That's a blessing despite some areas of the SE getting their hottest for the YTD later this week.

[FLweather]

8 hours ago, GaWx said:

 This one, Invest 90L, could turn out to be the 4th tropical system to impact this area and it is still July! If there's going to be impact here, this is how I like them, weak!

I agree.

Hard to tell if there is anything left of the MLC.

But obviously the SLC is southeast of Jacksonville this morning.

Looks like a wet day shaping up for FL and southern/central GA.

Definitely muggy this morning compared to yesterday.

Will be interesting to see how that feeder band progresses this afternoon with day time heating and seabreeze/meso boundaries.

[jconsor]

 

[GaWx]

Invest 90L may have fizzled in terms of TD potential (fine with me), but it is still having a significant impact on the GA coast with bands of moderate to heavy rains coming off the ocean, including at my place right now. This is the 4th tropical entity to do so here and we’re still in July! 

[Ed, snow and hurricane fan]

Slow part of the season question.  Texas has had a few Cat 4s, never a Cat 5.  Rare, but Florida has had at least 3.

1) Dry downslope air off Mexican/West Texas higher elevation deserts mix into a major storm approaching Texas, and/or

2) Warm but shallow water off Texas upwells.

 

I think both, but more likely the shallow water, dry air has to wrap in over warm water for a long time if shear isn't helping it.  (I read Derek Ortt's MS thesis, a well developed cyclone can resist dry air unless shear is pushing it directly into the circulation.)

[Windspeed]

Slow part of the season question.  Texas has had a few Cat 4s, never a Cat 5.  Rare, but Florida has had at least 3.
1) Dry downslope air off Mexican/West Texas higher elevation deserts mix into a major storm approaching Texas, and/or
2) Warm but shallow water off Texas upwells.
 
I think both, but more likely the shallow water, dry air has to wrap in over warm water for a long time if shear isn't helping it.  (I read Derek Ortt's MS thesis, a well developed cyclone can resist dry air unless shear is pushing it directly into the circulation.)

Geography does play a major role. Most TCs that strike Texas develop out of the WCARIB and must deal with land interaction of the Yucatán. This limits organizational/developmental time before RI can top out maximum potential energy. I am sure VWS relationship with dry continental airmass does play a role on occasion. However, typically westward vector is supported by easterly mid-level steering flow across the GOM. That should supercede dry airmass ever so often with these TCs. There have been some close calls however in documented history and almost certainly there have been many 155+ mph landfalls pre-colonialization. I'd wager Harvey would have attained Category 5 had it had more time over the GOM. Its structure was absurd well into post-landfall. The shallow shelf is sometimes plenty deep enough with 28°+C SSTs to support a Category 5 that is moving at a favorable rate of motion.

To the point, though we have not seen a Cat 5 strike Texas, it will eventually happen again whether we as humans are still around to witness it.

[nycwinter]

16 minutes ago, Windspeed said:

Geography does play a major role. Most TCs that strike Texas develop out of the WCARIB and must deal with land interaction of the Yucatán. This limits organizational/developmental time before RI can top out maximum potential energy. I am sure VWS relationship with dry continental airmass does play a role on occasion. However, typically westward vector is supported by easterly mid-level steering flow across the GOM. That should supercede dry airmass ever so often with these TCs. There have been some close calls however in documented history and almost certainly there have been many 155+ mph landfalls pre-colonialization. I'd wager Harvey would have attained Category 5 had it had more time over the GOM. Its structure was absurd well into post-landfall. The shallow shelf is sometimes plenty deep enough with 28°+C SSTs to support a Category 5 that is moving at a favorable rate of motion.

To the point, though we have not seen a Cat 5 strike Texas, it will eventually happen again whether we as humans are still around to witness it.

katrina rita were cat 5 in the gulf

[Ed, snow and hurricane fan]

If memory serves, Katrina and Rita made landfall as Cat 3s.

[Prospero]

1 hour ago, Ed, snow and hurricane fan said:

If memory serves, Katrina and Rita made landfall as Cat 3s.

Katrina was a monster 5 over the Gulf and then the eye mysteriously kept falling apart as it approached landfall. Just like all the storms off Texas last year that we all expected a perfect eye and they kept falling apart every few hours.

Yea, some random dry air, other unforeseen circumstances. But Katrina is the one I first remember with a "weird acting eye" and it was a scary monster and still ended up a monster...

[Windspeed]

katrina rita were cat 5 in the gulf

The question posed was to explain the lack of Cat 5 landfalls in Texas. I think it's a combination of factors, some just luck/chance, some geography. You mentioned Katrina and Rita. Those were Cat 5s that would eventually make landfall as 3s, but not in Texas. Harvey and the 1900 Galveston Hurricane are most likely the most powerful landfalls in Texas within record-keeping range. Hurricane Beulah in 1967 attained Category 5 status and would eventually make landfall as a 3 in Texas. Allen reached 5 multiple times but only made landfall as a 3 near Brownsville as well.

Let us not forget that Florida generally wins the Category 5 lottery for a reason. It is 1) a peninsula surrounded by Gulf Stream Loop & Current and 2) located within a higher frequency of high-end 'cane paths due to trade winds. But the idea here is that it would be unwise to assume hurricanes do not and will not strike Texas at Category 5 intensity.

Edit: Should have mentioned Carla '61 along with Harvey and the Galveston 1900 above. Also a correction: though the point of landfall was recorded in extreme SW Louisiana, Rita's weaker western eyewall was across the border in Texas. So it's a little cheap on my part to not consider Rita a Texas 'cane.

[Floydbuster]

Interesting discussion. I was reading about "return periods" for intense hurricanes here: https://journals.ametsoc.org/doi/full/10.1175/2007JCLI1772.1

They make an interesting discussion about the rarity of a sub-900 mb landfall in America, using the 1935 Labor Day Storm as their example.

Quote

The 1935 Labor Day Florida Keys storm was the most severe in our dataset. With a 265-yr wind speed return period and a 102-yr central pressure return period, it presses the fitted model boundaries. We believe this is due in part to the extreme southern latitude of this landfalling storm. Another storm of this intensity would likely again require a very southern landfalling latitude, with the Florida Keys or the Brownsville, Texas, region being the most likely hosts.
 

 

Using their models, we should be coming up on a sub-900 mb U.S. landfall within the next decade or two. I can definitely imagine a tightly-coiled pinhole eye sloshing ashore in Padre Island. Hurricane Anita 1977 comes to mind as a very close call. Without extra push from the high pressure to it's north, Anita would have made landfall as a 175 mph Category 5 in South Texas.

[shaggy]

Still a weak signal.for something in the super long range gefs.