2024 Hurricane Season Discussion

[tireman4]

Debby ashore in the Big Bend, and now the potential for historic flooding begins in Georgia and South Carolina
August 5, 2024 at 9:27 am by Matt Lanza







Headlines
Hurricane Debby made landfall near Steinhatchee, FL as an 80 mph category 1 hurricane at 7 AM ET.
The storm will now meander across Florida and Georgia, with weakening winds and increasing flooding problems.
Historic, catastrophic flooding is likely from Debby in portions of Georgia and South Carolina with widespread heavy rain causing flooding beyond those areas as well into Florida and North Carolina.
The next wave behind Debby has low odds to develop but should continue to be watched as it tracks generally due west.
Debby: 75 mph or less, moving NNE 10 mph or slower
Hurricane Debby made landfall near Steinhatchee, Florida this morning as a category 1 hurricane with maximum sustained winds of 80 mph.


Hurricane Debby just after making landfall near Steinhatchee, FL this morning as a category 1 hurricane. (College of DuPage)
Debby had a pressure of 979 mb, compared to 80 mph and 979 mb with Hurricane Beryl in Texas. Two storms, identical intensities, vastly different impacts. Cedar Key saw about 6 foot surge with Debby, compared to an 8 to 9 foot surge during Idalia last summer.


Comparison of storm surge during Hurricane Debby today and Hurricane Idalia last August in Cedar Key, FL. (NOAA)
Overall, surge and wind damage will likely be less than Idalia, but still rather widespread in parts of Florida. There will continue be periodic tornado warnings in Florida and perhaps Georgia or South Carolina as Debby’s bands spread across the area. Additionally, flooding is underway in parts of Florida that have seen the heaviest rain from Debby as it moves northward.


Hurricane Debby is meandering across Florida and headed toward Georgia as it begins to unleash its flooding rains. (RadarScope)
Debby is expected to slowly track northeast and east-northeast into Georgia today, with improving conditions in parts of Central Florida but continued heavy rain and gusty winds in North Florida and Georgia, as well as South Carolina. Debby may make its way back offshore on Tuesday or Wednesday, which could allow for some re-organization to the storm. We’ve seen this a lot in the past, where people see that the storm goes offshore and fear reorganization and another big one. Usually in these cases, the system can gain a hair of strength before it comes back ashore, so we aren’t worried about Debby rejoining the ranks of hurricane or anything. Look for Debby to slide offshore, then back onshore after 24-36 hours or so, remaining a tropical storm.

Debby’s rainfall

The primary threat from Debby will remain the rain. The rainfall forecast continues to call for in excess of 20 inches on the coast of South Carolina, including Charleston, with coastal Georgia, Hilton Head, and Savannah not far off. This is in addition to rain that has already fallen.


Extreme, historic rainfall will likely produce catastrophic flooding in South Carolina, Georgia, and perhaps even portions of North Carolina with Debby. (NOAA WPC)
This will all lead to potentially historic, catastrophic flooding for portions of South Carolina, possibly Georgia, and even some bad flooding in portions of North Carolina as well. It’s tough to show river forecasts, as they only include 48 hours of rainfall forecast data, but expect major to record flooding of multiple rivers in southeast Georgia and South Carolina as we head into midweek. Anyone living in a flood zone in those areas should be prepared to take quick and immediate action. This is a fairly high confidence forecast, with fairly minimal risk that it dramatically changes unfortunately.

If you’re curious about South Carolina flooding history as it pertains to tropical systems, Melissa Griffin, an assistant state climatologist put together a pretty outstanding overview at this link.

Our thoughts are with the folks in South Carolina and beyond that will be dealing with some pretty terrible weather this week.

What comes next?
The question in the tropics is always “what’s next?” Well, we continue to watch a tropical wave moving into the Caribbean. This will carry about a 30 percent chance of development right now as it comes west.


The NHC is carrying about a 30 percent chance of development with the next system as it moves into the western Caribbean or Bay of Campeche. (NOAA NHC)
Model support for this one is not terribly strong. Odds of 30 percent seem very reasonable at this point. Yes, the GFS operational crashed a storm into Texas overnight, but it is quite the outlier right now, with little to no support from other models. One reason to expect that this system would continue to go west or west northwest is a large ridge of high pressure that’s expected to establish over Texas this week and perhaps much of next week as well. The five day average for the weekend and next week (when the GFS shows the system making it to Texas) from the European ensemble shows a rather robust pattern of high pressure.


High pressure over Texas should help steer tropical activity south of the U.S. and northern Mexico for the time being. (Tropical Tidbits)
This pattern looks similar to last summer, where Texas was essentially “shielded” from tropical activity by a persistent ridge. We do not expect that this is going to hold up beyond next week right now, but for this particular tropical wave, I would say that a track into the Bay of Campeche or southward is most likely at this time.

There is another wave behind this one that may try to develop in the open Atlantic next week. As of now, we don’t see any significant landfall threats anywhere in the tropics, but we’ll be watching.

Who wrote this discussion? Imo, that's not a very good idea to be suggesting the idea currently that the Caribbean system will not pose any type of threat to Texas. It's way too early to make that call and as we learned with Beryl, models cannot be trusted beyond 3 days.

Edit: I see now it's Matt Lanza. I respectfully disagree writing an outlook like this. That's like trying to predict where severe weather will take place in a week based off of one model run. I've done that before for a class and it's nearly impossible.

My dear Captain, it was not me. LOL. How many classes are you taking this fall?

[tireman4]

Matt Lanza 08 05 24

For those seeing the GFS operational model that does take a tropical system to Texas next week, just a reminder that operational models and ensemble guidance used in concert are a good method. Here's that op run, along with the 8 day ensemble spaghetti plot. Of the 30 GFS ensemble members, about 3-5 make it to the Gulf; most are suppressed and weak. Does it mean we won't see the GFS verify? Of course not, but at this time, it is an extremely distinct outlier.

[Stratton20]

3-5? I count more like 9-10 lol

[Pas_Bon]

As was discussed during and in the aftermath of Beryl, my biggest issue with SCW is that they use definitive language far too early. I assume it's tied to their goal of providing "hype-free" forecasts. I think you can still provide a hype-free forecast while also making it clear it's far too early to dismiss any outcomes outright.

I think the bigger issue with Matt Lanza is how he acts, especially in regards to Beryl, in the face of criticism.

My limited experience has been that he is extremely defensive

They whiffed majorly with the derecho (most did) and Beryl

Their recent track record is not good

They were great for Harvey

[Pas_Bon]

My take on Matt Lanza is that he’s very knowledgeable, but very much averse to anyone having an alternate viewpoint or challenging respectfully. I was hoping they’d have learned something from their coverage of Beryl, but it appears not. For him to sully any possibility of a future Ernesto having a Texas endpoint this early is pompous and dangerous, IMO

[biggerbyte]

I totally agree. Long range guarantees are very irresponsible. Without naming any names, at least one popular meteorologist said hands down Beryl was a Mexico problem.. This individual argued the point down to the last couple of days. We see what happened there. I've never ever tried to lock down beyond three days. It is just pointless.

Weather predictions can be comical sometimes. Some folks like to raise the ego flag when a suggestion turns out to be a solution, but runs from the conversation when it's wrong. There should not be condemnation or praise. The art of saving lives is to bring awareness with an obvious disclosure.

[cperk]

Fortunately we don't have to listen Matt Lanza we have trusted sources on this forum the NWS and the NHC we're good.

[Stratton20]

Their are 3 possible outcomes with this, because I know someone on social media is gonna say this wave isnt gonna develop now when they see the 18z GFS
1. The wave crashes into nicaragua and never develops like what the 18z GFS shows
2. The wave develops near nicaragua but gets steered into the BOC and Mexico by strong ridging
3. The wave develops in the yucatan channel and ends up more in the gulf, taking a more NW track potentially threatening the gulf coast


All three scenarios are possible, while overall support is low right now, the wave is convectively active right now and its headed toward a more favorable environment in the western caribbean, this one bears close watching despite support being sort of just meh right now

[captainbarbossa19]

Debby ashore in the Big Bend, and now the potential for historic flooding begins in Georgia and South Carolina
August 5, 2024 at 9:27 am by Matt Lanza







Headlines
Hurricane Debby made landfall near Steinhatchee, FL as an 80 mph category 1 hurricane at 7 AM ET.
The storm will now meander across Florida and Georgia, with weakening winds and increasing flooding problems.
Historic, catastrophic flooding is likely from Debby in portions of Georgia and South Carolina with widespread heavy rain causing flooding beyond those areas as well into Florida and North Carolina.
The next wave behind Debby has low odds to develop but should continue to be watched as it tracks generally due west.
Debby: 75 mph or less, moving NNE 10 mph or slower
Hurricane Debby made landfall near Steinhatchee, Florida this morning as a category 1 hurricane with maximum sustained winds of 80 mph.


Hurricane Debby just after making landfall near Steinhatchee, FL this morning as a category 1 hurricane. (College of DuPage)
Debby had a pressure of 979 mb, compared to 80 mph and 979 mb with Hurricane Beryl in Texas. Two storms, identical intensities, vastly different impacts. Cedar Key saw about 6 foot surge with Debby, compared to an 8 to 9 foot surge during Idalia last summer.


Comparison of storm surge during Hurricane Debby today and Hurricane Idalia last August in Cedar Key, FL. (NOAA)
Overall, surge and wind damage will likely be less than Idalia, but still rather widespread in parts of Florida. There will continue be periodic tornado warnings in Florida and perhaps Georgia or South Carolina as Debby’s bands spread across the area. Additionally, flooding is underway in parts of Florida that have seen the heaviest rain from Debby as it moves northward.


Hurricane Debby is meandering across Florida and headed toward Georgia as it begins to unleash its flooding rains. (RadarScope)
Debby is expected to slowly track northeast and east-northeast into Georgia today, with improving conditions in parts of Central Florida but continued heavy rain and gusty winds in North Florida and Georgia, as well as South Carolina. Debby may make its way back offshore on Tuesday or Wednesday, which could allow for some re-organization to the storm. We’ve seen this a lot in the past, where people see that the storm goes offshore and fear reorganization and another big one. Usually in these cases, the system can gain a hair of strength before it comes back ashore, so we aren’t worried about Debby rejoining the ranks of hurricane or anything. Look for Debby to slide offshore, then back onshore after 24-36 hours or so, remaining a tropical storm.

Debby’s rainfall

The primary threat from Debby will remain the rain. The rainfall forecast continues to call for in excess of 20 inches on the coast of South Carolina, including Charleston, with coastal Georgia, Hilton Head, and Savannah not far off. This is in addition to rain that has already fallen.


Extreme, historic rainfall will likely produce catastrophic flooding in South Carolina, Georgia, and perhaps even portions of North Carolina with Debby. (NOAA WPC)
This will all lead to potentially historic, catastrophic flooding for portions of South Carolina, possibly Georgia, and even some bad flooding in portions of North Carolina as well. It’s tough to show river forecasts, as they only include 48 hours of rainfall forecast data, but expect major to record flooding of multiple rivers in southeast Georgia and South Carolina as we head into midweek. Anyone living in a flood zone in those areas should be prepared to take quick and immediate action. This is a fairly high confidence forecast, with fairly minimal risk that it dramatically changes unfortunately.

If you’re curious about South Carolina flooding history as it pertains to tropical systems, Melissa Griffin, an assistant state climatologist put together a pretty outstanding overview at this link.

Our thoughts are with the folks in South Carolina and beyond that will be dealing with some pretty terrible weather this week.

What comes next?
The question in the tropics is always “what’s next?” Well, we continue to watch a tropical wave moving into the Caribbean. This will carry about a 30 percent chance of development right now as it comes west.


The NHC is carrying about a 30 percent chance of development with the next system as it moves into the western Caribbean or Bay of Campeche. (NOAA NHC)
Model support for this one is not terribly strong. Odds of 30 percent seem very reasonable at this point. Yes, the GFS operational crashed a storm into Texas overnight, but it is quite the outlier right now, with little to no support from other models. One reason to expect that this system would continue to go west or west northwest is a large ridge of high pressure that’s expected to establish over Texas this week and perhaps much of next week as well. The five day average for the weekend and next week (when the GFS shows the system making it to Texas) from the European ensemble shows a rather robust pattern of high pressure.


High pressure over Texas should help steer tropical activity south of the U.S. and northern Mexico for the time being. (Tropical Tidbits)
This pattern looks similar to last summer, where Texas was essentially “shielded” from tropical activity by a persistent ridge. We do not expect that this is going to hold up beyond next week right now, but for this particular tropical wave, I would say that a track into the Bay of Campeche or southward is most likely at this time.

There is another wave behind this one that may try to develop in the open Atlantic next week. As of now, we don’t see any significant landfall threats anywhere in the tropics, but we’ll be watching.

Who wrote this discussion? Imo, that's not a very good idea to be suggesting the idea currently that the Caribbean system will not pose any type of threat to Texas. It's way too early to make that call and as we learned with Beryl, models cannot be trusted beyond 3 days.

Edit: I see now it's Matt Lanza. I respectfully disagree writing an outlook like this. That's like trying to predict where severe weather will take place in a week based off of one model run. I've done that before for a class and it's nearly impossible.

My dear Captain, it was not me. LOL. How many classes are you taking this fall?

Oh I did not think it was you. It looked like a shared article to begin, but somehow I glanced over the author.

To answer your question, I am taking 4 classes this fall including differential equations and meteorology dynamics 1. Will be officially earning my degree next spring!

[tireman4]

Fortunately we don't have to listen Matt Lanza we have trusted sources on this forum the NWS and the NHC we're good.

I post Matt's takes because 1) He is a pro met, 2) Even if he has differen opinions, he still has a BS in Meteorology 3) I do post other pro Mets opinions on here too ( Timmer, Berger, Matthew's, et al). I agree with Cperk we do have sources such as the NHC and NWS as well. Remember, this is a discussion board. We all discuss.

[Pas_Bon]

Fortunately we don't have to listen Matt Lanza we have trusted sources on this forum the NWS and the NHC we're good.

I post Matt's takes because 1) He is a pro met, 2) Even if he has differen opinions, he still has a BS in Meteorology 3) I do post other pro Mets opinions on here too ( Timmer, Berger, Matthew's, et al). I agree with Cperk we do have sources such as the NHC and NWS as well. Remember, this is a discussion board. We all discuss.

They all have intelligent takes. They all have flaws. They all are wrong sometimes. Such is the science. They also all have a duty to not foster hysteria and also, not foster complacency or misguided safety

[Pas_Bon]

Today’s flavor seems to favor the high pressure dome staying put over Texas for the next week and change. It looks as if right now, any future system will steer well South of us. Let’s hope it stays that way.

[Stratton20]

Pas_Bon na give me a weak system over this heat crap anyday lol

[Pas_Bon]

Pas_Bon na give me a weak system over this heat crap anyday lol

That’s true. The problem is, I don’t trust any system in August or September to be weak. Lol

[Stratton20]

Fair enough, unfortunately it looks like this wave is going to just crash into the CA, i would love a weak tropical storm- to give me a break from this miserable, mosquito infested weather

[tireman4]

Matt Lanza...

3 Consecutive GFS runs with nothing in the Gulf next week. And no ensemble support for anything either. From either the GFS or Euro. My Texas crowd can breathe a little more. We will continue to watch.

[Pas_Bon]

Matt Lanza...

3 Consecutive GFS runs with nothing in the Gulf next week. And no ensemble support for anything either. From either the GFS or Euro. My Texas crowd can breathe a little more. We will continue to watch.

I’ll agree with him on this.

I will say that this hurricane season seems like it is a major bust at this point compared to the hype it was given (there was great reason for the hype)
It may be considered busy for a “normal” season analog, but it sure seems that storms are having a hard time getting going

[tireman4]

The Eyewall 08 06 24


Read on blog or Reader
Site logo image The Eyewall
Debby’s flooding continues to swamp parts of the Southeast and will spread north
By Matt Lanza on August 6, 2024

Headlines
Heavy rain from Debby will continue to impact South Carolina today and tomorrow.
Heavy rain expands northward after tomorrow with flash flooding likely into North Carolina and Virginia.
Combination of heavy rain today and Debby's remnants may cause flash flooding in the Mid-Atlantic and New England by late week.
The 30% area in the Caribbean continues to look middling for awhile, and it is likely to stay somewhat suppressed to the south into next week.

Rainfall forecast for the next 5 days shows upwards of 10 to 15 inches or more of additional rain in the Carolinas, as well as a corridor of heavy rain in Pennsylvania, New Jersey, New York, and New England. (NOAA WPC)
Tropical Storm Debby's heavy rain expands this week
Tropical Storm Debby is still a formal entity this morning, with 45 mph winds, and it is now drifting back offshore of Georgia, where it's expected to meander through tomorrow night. It will then likely come back onshore Thursday and lift north and finally out on Friday. But before it does that, it will continue to dump copious amounts of rain on the Carolinas with an increasing signal for flooding to the north as well. Let's walk day by day.


Radar estimated rainfall over South Carolina, showing maximum totals between Charleston and Savannah on the order of 8 to 14 inches or so. (NOAA MRMS)
Today

With Debby meandering offshore, expect heavy rain to basically continue in place. There will be rainfall rates of 2 to 4 inches an hour at times, mainly north of Hilton Head and south of Columbia. But, as 6 to 12 inches of rain has already fallen, flash flooding is underway, and it will continue.


A high risk of flash flooding (level 4/4) exists across eastern Georgia, much of southeastern South Carolina and southern North Carolina today. (NOAA WPC)
As Debby drifts a little farther offshore, the rain may become a little more scattered or intermittent, but it will continue to potentially flood areas through the day. Debby should not gain much intensity today as it meanders offshore, as it will be getting its bearings.

For a look at river forecasts in South Carolina, follow this link.


(NOAA NHC)
Wednesday

Debby will continue to meander offshore, but with generally low shear and warm water off the coast of South Carolina, it will likely begin to reorganize some. It could become a strong tropical storm again as it turns back northward toward the South Carolina coast later tomorrow.


Water temperatures off the South Carolina and Georgia coasts are running as much as 1°C above normal, favorable for Debby's intensification. (Weather Bell)
On Wednesday, the flooding threat mostly exits Georgia and is confined to South Carolina and extreme southeastern North Carolina, including Wilmington, Myrtle Beach, and Charleston. Travel on I-95 may be a bit difficult as well through the Florence area, depending on exactly where the heaviest rainfall sets up. Another high risk is in effect in this area.

Thursday

Debby should move back inland across South Carolina on Thursday. Storm surge will again be a concern (as will high tides between now and Thursday).


Surge of 2 to 4 feet above ground level is possible along the South Carolina coast and nearby adjacent waters as Debby meanders offshore and comes back ashore Thursday. (NOAA NHC)
Surge of 2 to 4 feet will be possible along the South Carolina coast and possibly parts of Georgia and North Carolina as well with Debby moving around offshore and coming back onshore.

As Debby comes north a little more steadily Thursday, heavy rain will spread into North Carolina. While flooding risk will have mainly been confined to the extreme southeast corner of the state to this point, there will be a pretty significant expansion of heavy rain northward on Thursday that will engulf more of the state, including the Sandhills, the Raleigh-Durham area, and portions of the Piedmont in a moderate or high risk of excessive rain and flash flooding.


A high risk (level 4/4) of excessive rain and flooding will expand deep into North Carolina on Thursday, with moderate (level 3/4) risk surrounding it over a wide area even into Virginia. (NOAA WPC)
Most of the rain on Thursday will front run Debby, as the south side of its circulation will probably have lesser rain and more scattered showers. As the center gets across North Carolina late Thursday and Thursday night, we'll see conditions slowly improve. But some serious flash flooding is a concern in both rural and urban areas of the eastern half of the state.

Friday-Saturday

Debby will continue to come northward on Friday, likely tracking across Virginia and eventually being absorbed by a trough digging into the Midwest and Great Lakes. What does this mean? Debby will become extratropical here, meaning it'll transition from a tropical storm or depression into low pressure, a process that is meteorologically noteworthy but will have little impact on impacts seen. Heavy ran will spread across Virginia and into portions of Maryland, Pennsylvania, and New York here. These areas are expecting heavy rainfall today as well, so with soils saturated, additional rainfall from Debby will exacerbate issues.


Rainfall between today's storms and Debby's remnants will add up to over 6 inches in spots between Pennsylvania, New Jersey, New York, and New England. (Pivotal Weather)
Flash flooding is likely on Friday or Saturday as Debby's exit strategy unfolds. This may include Philly, New York, and Boston.

From here, Debby's remnants will accelerate out, likely bringing some locally heavy rain and gusty winds to portions of Quebec and Atlantic Canada. And we can finally close the book on Debby.

Rest of the tropics
We continue to watch a tropical wave with a 30 percent chance of development per the National Hurricane Center. This doesn't look like much today, but as it comes west it may develop.


A tropical wave with minimal thunderstorm activity in the southern Caribbean has about a 30 percent chance to develop as it comes west. High pressure over Texas and the South will likely keep it tracking toward Mexico. (Weathernerds.org)
I will say that some of the more aggressive modeling with this wave has backed off considerably in the last 24 hours, and at this point there is minimal operational or ensemble model support for any development. 30 percent seems reasonable, if not a little aggressive right now. Regardless, high pressure over Texas and South will probably keep this wave fairly suppressed and tracking toward Mexico next week. We'll continue to watch.

Behind this, there are no other areas of interest highlighted by the NHC, but the next wave emerging off Africa is showing some signs of developing in modeling. We have about a week to watch before anything happens with that one, so we won't over-speculate. All in all, as we get into the mid-August period, things look average. That's good. I'm sure it won't last, but we'll hopefully have a couple days after Debby to exhale and regain our bearings.

[Cromagnum]

Matt Lanza...

3 Consecutive GFS runs with nothing in the Gulf next week. And no ensemble support for anything either. From either the GFS or Euro. My Texas crowd can breathe a little more. We will continue to watch.

I’ll agree with him on this.

I will say that this hurricane season seems like it is a major bust at this point compared to the hype it was given (there was great reason for the hype)
It may be considered busy for a “normal” season analog, but it sure seems that storms are having a hard time getting going

All it takes is one for someone to consider it a bad season. For me, I'm already done and don't want anymore.

[Pas_Bon]

Matt Lanza...

3 Consecutive GFS runs with nothing in the Gulf next week. And no ensemble support for anything either. From either the GFS or Euro. My Texas crowd can breathe a little more. We will continue to watch.

I’ll agree with him on this.

I will say that this hurricane season seems like it is a major bust at this point compared to the hype it was given (there was great reason for the hype)
It may be considered busy for a “normal” season analog, but it sure seems that storms are having a hard time getting going

All it takes is one for someone to consider it a bad season. For me, I'm already done and don't want anymore.

Ok. The adage being true. I get it. But we were supposed to have record numbers of storms forming. I’m done, too, by the way. I’m not ballyhooing a relatively inactive lull we’ve had - Debby and Beryl aside, but where are the storms?