Matt Lanza

Category 4 Hurricane Helene continuing to grow with little forecast change this morning (UPDATED 6:50 PM ET Thurs)

(6:50 PM ET Update): Helene is now a category 4 hurricane with maximum sustained winds of at least 130 mph. Helene is pretty clearing undergoing a rapid intensification cycle at present, and the only question at this point is if it will level off before it makes landfall. The track continues to wobble a bit, perhaps on the right side of the specific track, but in general, the forecast remains steady.

(NOAA NHC)

For Tallahassee, it remains really a question of whether it’s really bad or terribly bad. So, neither outcome is great. Looking at satellite imagery this evening, the west side of this thing is no picnic either. Yes, the “dirty” side is living up to its name, but the thunderstorms in the northwest quadrant are going to cause significant wind and rain, and even if this tracks east of Tallahassee, it’s going to be a really bad night.

Hurricane Helene is a massive storm. (Weathernerds.org)

Landfall is expected later this evening, probably close to midnight.

Rainfall will continue to lead to severe flooding well north of where Helene comes ashore. Flood warnings extend in broken fashion from just west of Tallahassee through Atlanta to Charlotte, into far southwest Virginia. Catastrophic flooding remains a strong possibility in the mountains.

Numerous flood (green), tornado (red), and special marine warnings were in effect at 6:50 PM ET. (RadarScope)

Water levels continue to rise on the Florida coast, and the expected catastrophic storm surge north of Tampa through Apalachee Bay will proceed apace in the coming hours. Avoid the coast, do not go see it, it will be deadly. More to come later this evening.

(2:45 PM ET Update): Hurricane Helene is now a 120 mph major hurricane.

(11:25 AM ET Update): The 11 AM ET advisory is out with Helene up to 105 mph. Its structure and organization have improved since earlier. The track forecast has not shifted much in the new advisory, but it’s noteworthy that there have been a few wobbles to the east side of the track forecast.

Track forecast and satellite loop (University of Wisconsin)

Wobbles are normal with hurricanes of this size and intensity. The question is whether or not they fundamentally alter the track, particularly at this angle of approach. For most folks in the path of Helene, this has minimal impact on the end result. But for a place like Tallahassee, ending up on the west side of the storm would be immeasurably less impactful than the east side. Still bad to be sure, but not quite as bad as it could be otherwise. This would also impact the western fringe of the surge forecast a bit too. So it’s something to monitor through the day today if you have interests in Tallahassee or along Apalachee Bay.

Whatever the case, nothing has appreciably changed, and a major hurricane is still expected at landfall tonight around Midnight, give or take.

(NOAA NHC)

Tropical Storm and Hurricane warnings still extend almost absurdly far inland, but they will almost certainly verify.

A couple other notes: We already have additional numerous flash flood warnings near Tallahassee, between Macon and Augusta, just north of Greenville, SC, south of Asheville, near Johnson City, TN, and up into Virginia. The inland flooding component will continue to worsen as the day continues.

Tornado warnings have been numerous, and we currently have 3 warnings as I write this in Georgia and South Carolina. This system has the potential to be a prolific tornado producer from Florida into southeast Georgia, South Carolina, and parts of North Carolina. Please ensure you have a way to receive warnings, even if you’re 250 miles from the center of the storm.

Previous post follows…

What’s changed since last night

  • No meaningful change to the forecast intensity, track, or impacts into Florida.
  • A slight nudge east in the track in North Georgia.
  • Helene is now a category 2 storm

Larger storms tend to be a little more unruly in terms of how they organize. Helene meets that bill today. Reports of “concentric eyewalls” in the storm, almost as if the system is trying to figure out how large it wants to be.

Helene continues to evolve into the storm it will come ashore as, likely now a category 2 hurricane. (Tropical Tidbits)

We’ve seen bursts of thunderstorms wax and wane near the center, but we’re currently in an uptick. Recent reports from NOAA flights into Helene suggest surface winds have increased to close to 100 mph. We’ll see what the new advisory shows just after I publish this. (Editor’s note: It has. Now a cat 2 with 100 mph winds). Basically, Helene continues to intensify, and there’s no reason to think the dire forecasts we and everyone else discussed yesterday have changed.

The surge forecast is basically unchanged from last night, with a 15 to 20 foot, unsurvivable peak surge in Apalachee Bay and the Big Bend.

The storm surge forecast is virtually unchanged from last night, with catastrophic surge expected between Apalachicola and the Anclote River. (NOAA NHC)

Tampa Bay continues to see a 5 to 8 foot surge, which will be some of the worst surge experienced in modern times there.

The track of Helene is virtually unchanged as well. The most likely landfall point is between Apalachicola and Steinhatchee right now. There remains at least some risk that wobbling of the track could force it closer to Cedar Key in an extreme scenario. I would not rule that out, but I would be absolutely preparing for the worst between Apalachicola and Homosassa and for very bad outcomes south of there to Tampa Bay. Landfall should occur late this evening.

A Tornado Watch is in effect for most of the Florida Peninsula today.

A Tornado Watch is in effect for most of the Peninsula through 8 PM ET. Further watches could be required north of there into southeast Georgia later. (NOAA SPC)

That watch goes til 8 PM ET, and additional watches could be required to the north later today. Isolated tornadoes seem to already be a bit of a threat and this should escalate some through the day and into tonight.

The heavy rainfall threat continues to look very, very bad for both areas near landfall and interior locations in the Appalachians in North Carolina, Upstate South Carolina, and North Georgia.

High risk of flash flooding (level 4/4) north of Atlanta into Asheville, NC today, as well as in southwest Georgia and near where Helene comes ashore in the Panhandle. (NOAA WPC)

After heavy rain yesterday, we continue to see the risk for 10 to 16 inches of additional rainfall with the storm today, tonight, and early Friday before things slowly ease up a little tomorrow. Catastrophic interior flooding, especially in that high risk area northeast of Atlanta remains a high likelihood.

Real quick tangent here. One of the reasons Helene is going to be such a monster storm as it comes inland is because it’s essentially “phasing” with a massive upper cutoff low over the mid-South. A cutoff low is a storm system in the upper atmosphere that has essentially cut itself off from the jet stream. When this happens, the system tends to just meander around until something changes to kick it out. In this situation, you can see the animation below with the big upper low north of Memphis, and then Helene surging in on the right side of the image.

The merger between a baroclinic system (cutoff low) and a hurricane over Tennessee and Kentucky allows for Helene’s winds to survive longer than they otherwise would. (Pivotal Weather)

This complex merger is something we don’t usually think of with a hurricane. Hurricane Sandy was a good example of this happening with tropical systems and showed why its winds and size caused so much damage despite “not technically being a hurricane” when it hit New Jersey in 2012. The whole process extends the life cycle of the winds of the hurricane and it’s why tropical storm warnings extend so far inland. The rain element is related as well. With Helene being pulled northeast, then suddenly hooking back northwest “into” the upper low, it will continue to produce rain on the windward side of the Appalachians, leading to additional rain tomorrow and further flooding.

Anyway, that explains some of what’s going on behind the scenes with Helene after it moves inland. We’ll update this post with any notable changes throughout the day.

Forecast for Helene continues to escalate in a bad way for Florida’s Big Bend region and for inland locations (UPDATED: 11 PM ET Wed)

(11 PM ET update): The 11 PM ET advisory is out with few changes. No forecast changes have been made, and no intensity changes have been made.

Helene is still mixing out some dry air, and it’s large size is slowing the intensification process somewhat. We should see the system better organize overnight and on Thursday morning. (Tropical Tidbits)

Helene is still organizing, and it seems that the size of Helene is acting to keep that intensification steady for now. As the system hits the ultra warm water in the Gulf and a more favorable environment internally, it will likely strengthen at a steady, faster pace tomorrow before making landfall tomorrow night.

There have been no notable changes to the surge or rainfall forecasts unfortunately. We’ll have an update in the morning.

Previous post follows…

Changes since this morning

  • Storm surge forecasts have been increased on the Florida coast with a surge as high as 20 feet expected between Carrabelle and the Suwannee River.
  • Helene is expected to be a category 4 storm at landfall.
  • The high risk of flooding has been expanded tomorrow in both the Carolinas and in Georgia/Florida.
  • Tropical Storm Warnings are now posted for the rest of Georgia, all of South Carolina, and portions of western North Carolina and Tennessee.
  • Helene is likely to be the modern storm of record for Florida’s Big Bend Region and possibly some other areas.

This blog is committed to no-hype because of storms like Helene. This one merits your full attention and full preparedness if you are anywhere in the area that will be affected by the storm. This includes all of Florida except the far western Panhandle, all of Georgia, eastern Alabama, almost all of South Carolina, western North Carolina, and Tennessee. We cannot stress this enough. Follow the advice of local officials. This is almost certainly going to be a major storm, and most of the data suggests that this will be a catastrophic storm in several places.

There’s no way we can cover all the elements of this storm, but we’ll try.

Storm surge

The storm surge forecast is, frankly, hideous. The forecast surge values, should they verify, will be worse than any modern storm has brought to the area between Tampa Bay and Apalachee Bay.

An absolutely catastrophic surge event is forecast for the areas north of Pasco County, FL. A historic surge event is likely south of there into Tampa Bay with substantial surge also in southwest Florida. (NOAA NHC)

The surge will be worse than Idalia all across the Big Bend Region, Apalachee Bay, the Nature Coast, and Tampa Bay. It will probably be the new benchmark for modern storms in this region. The surge will drop off dramatically to the west of where the center comes ashore, so folks in Panama City and Mexico Beach will only see a minor surge from this, with a huge escalation near and to the east of where the eye comes ashore. If these forecasts verify, this will be unsurvivable type surge in the region east of Carrabelle through about Cedar Key. I cannot stress enough how serious the storm surge from Helene may be.

Wind

Obviously with a cat 4 hurricane expected, there will be catastrophic wind at the immediate coast. But with Helene’s acceleration north, the wind will spread far inland.

Tropical storm force winds will extend into the Carolinas. Hurricane force winds will extend deep into Georgia. Catastrophic hurricane winds may get as far north as Tallahassee or Valdosta depending on the exact track. (NOAA/Google Earth)

We expect hurricane force winds to get deep into Georgia. The exact track will be critical in determining if Tallahassee sees catastrophic damaging winds or something more manageable. It will be close. It will probably be less close in Valdosta, GA which could see gusts in excess of 100 mph. Those winds will slowly decelerate deeper into Georgia, but hurricane force winds could get as far north as Macon. Strong tropical storm winds will impact metro Atlanta, especially on the south side and perhaps creeping close to Athens. Tropical storm force winds will be an issue deep into South Carolina and western North Carolina, as well as eastern Tennessee. There will be widespread wind damage and widespread, likely significant power disruption. This is a very bad looking storm.

Rain & flooding

We continue to see a high risk of excessive rain leading to flash flooding, possibly catastrophic flash flooding in two areas tomorrow. First is where Helene comes ashore in Florida, which will see substantial rain — what you would expect from a landfalling category 4 storm.

Thursday’s excessive rainfall outlook for south Georgia and the Florida Panhandle. (NOAA WPC)

The storm will dump heavy rain and produce widespread flash flooding across Georgia, eastern Alabama and portions of South Carolina as well. But when the storm interacts with the Appalachians, that’s when severe flooding issues could creep up. The high risk was expanded south into metro Atlanta, especially north and east of the city. And it continues through Asheville, NC, including much of Upstate South Carolina north and west of Greenville-Spartanburg. Portions of the Smokeys will also be impacted.

High risk of flash flooding between about Gwinnett County, GA and Smokeys and southern Blue Ridge on Thursday (NOAA WPC)

The interaction of terrain with a hurricane can produce copious amounts of rain leading to destructive flooding and landslides, and that’s the concern in Appalachia. Again, I cannot stress enough how serious an event this may be in those areas. It’s a much different hazard than storm surge but extremely dangerous just the same.

Tornadoes

Isolated tornadoes are likely anywhere east of Helene’s center, so be aware of that risk in the Florida Peninsula, the Jacksonville area, and much of eastern Georgia and the Carolinas.

Again, we strongly encourage you to follow local officials, follow local media, and do everything possible to get out of harm’s way. This is not a storm you want to roll the dice on. We’ll update this post later this evening with any relevant new info. Look for a full post again in the morning.

Helene likely to become a hurricane today, delivering complex, damaging impacts for Florida and much of the Southeast (UPDATED: 2:25 PM ET)

(2:25 PM ET Update): The storm surge forecast has been increased to 12 to 18 feet in the Big Bend, now well above the levels set during Idalia last year. This has potential to be the benchmark event for this region historically.

Storm surge forecast for Florida has increased. (NOAA NHC)

(1:20 ET Update): Hurricane Helene is here, as it has strengthened enough to cross the threshold to hurricane intensity. Winds are 80 mph, and strengthening into a borderline Category 3 or 4 hurricane is expected up to landfall tomorrow night.

Hurricane Helene avoided landfall on the Yucatan and is now set to traverse very, very warm water up to landfall. Helene is a sprawling, large storm. (Weathernerds.org)

Helene will rapidly intensify into a major hurricane tonight or tomorrow. SHIPS model guidance shows a 10 times greater than normal chance of Helene adding 50 mph to its intensity over the next 36 hours, which would place the storm on the cusp of category 4 intensity.

Whatever it becomes at this point may matter little, as the impacts now seem set: Catastrophic storm surge, worse than Idalia for the Big Bend and Nature Coast, severe storm surge in Tampa Bay, significant wind damage from the Big Bend and Panhandle deep into Georgia, and potentially catastrophic flooding in North Georgia and the Carolinas. Among other impacts. For the U.S., Helene appears to be the most significant threat of the 2024 hurricane season.

The surge forecast has changed little from this morning, though the 10 to 15 foot values were nudged a bit west to Carrabelle, FL. Again, this is likely to be much worse than Idalia and over a larger area.

The landfall forecast continues to hold steady. Expected landfall is in or very near Apalachee Bay.

Inland tropical storm watches and warnings have been expanded today and now cover parts of Alabama, all of Georgia, much of South Carolina, and western North Carolina.

Watches and warnings cover a huge swath of the Southeast from the coast to hundreds of miles inland. (Pivotal Weather)

We continue to watch the rainfall outlook very closely. Unfortunately, many areas will be drenched today by a predecessor rain event (PRE) that will exacerbate flooding as Helene itself comes inland tomorrow night. As much as 2 to 5 inches of rain are expected today and tonight across Georgia and into North Carolina.

Heavy rain will fall today from west-central Georgia into western North Carolina, with a high risk of flash flooding. Flooding will worsen tomorrow and tomorrow night as Helene approaches and winds kick up. (Pivotal Weather)

With more rain tomorrow and the storm itself not arriving until tomorrow night and Friday, conditions will steadily deteriorate into Friday in those areas, and the severity of flash flooding will worsen. This will be a prolonged, extremely serious flooding event for North Georgia, Upstate South Carolina, and western North Carolina. Landslides, at least moderate river flooding, and possibly major river flooding is a safe bet in those areas. Current forecasts indicate perhaps as much as 20 inches of rain in some southeast facing mountains in western North Carolina.

We will update again later today.

What’s changed since yesterday

  • Helene’s forecast intensity as it approaches Florida has been increased a bit, with risk for further increase in the intensity forecast today. Folks between Port St. Joe and Cedar Key should be preparing for major hurricane impacts.
  • Hurricane Warnings extend into Georgia, a good bit beyond Valdosta. Tropical Storm Warnings now cover virtually the entire Florida Peninsula. Tropical Storm Watches extend into central Georgia and much of southeastern South Carolina.
  • Helene’s track and surge forecast is relatively unchanged.
  • The interior rainfall forecast has escalated, and there is growing risk of a potentially damaging, catastrophic flash flooding event from northeast Georgia into western North Carolina, including Asheville.
Helene’s forecast to come ashore near Apalachee Bay as a major hurricane. (NOAA NHC)

Not a whole lot has changed since yesterday. It’s nice to have a consistent forecast, but this is certainly turning into quite a serious situation for the eastern Florida Panhandle and Big Bend. Again, the minimum you should expect right now is an Idalia-type impact. For many, if not most places between Apalachee Bay and Tampa, this will probably be a worse impact than Idalia. Current surge forecasts continue to suggest impacts at or above Idalia. This surge forecast is virtually unchanged from 12 hours ago.

Potential max storm surge forecasts are as bad or worse than Idalia and unchanged since yesterday. (NOAA NHC)

There’s honestly not a whole lot that needs to be said here with respect to the Florida coast between Cedar Key and Apalachee Bay: This has a decent chance to be worse than Idalia was and you should be closely following the advice of local officials.

The track forecast isn’t entirely locked down, but it’s close to it right now. There are still a handful of model data points suggesting a track slightly farther east than currently shown by the majority of tropical models and the official NHC forecast. This won’t hit Tampa directly, but a track closer to Cedar Key or Steinhatchee is possible, a Nature Coast/Big Bend hit more than an Apalachee Bay hit. This is why we encourage everyone from Port St. Joe to Homosassa or Clearwater to prepare for a significant hurricane hit, be it via surge, wind, or both.

Hurricane force winds are expected to extend deep into Georgia, perhaps north of Tifton and near Albany. Tropical storm force winds will extend possibly into Metro Atlanta and much of South Carolina. (NOAA NWS)

It’s also important to note how deep into Georgia hurricane-force winds are expected to go. That takes them close to Albany, GA and about halfway to Macon. Tropical storm force winds are expected to extend north of Macon to metro Atlanta and into South Carolina. This will almost certainly cause widespread power outages, and folks should be prepared to be without power for at least a few days.

Here is a list of major cities and their maximum wind gust forecasts from the NWS Point and Click forecasts as of Wednesday morning. These are likely to change:

(Editor’s Note: We will update these later today with slightly better data than point & click forecasts)

Florida
Tallahassee: 63 mph
Cedar Key: 80 mph
Apalachicola: 77 mph
Panama City: 54 mph
Clearwater: 60 mph
Tampa: 59 mph
Sarasota: 72 mph
Fort Myers: 57 mph
Naples: 56 mph
Orlando: 49 mph
Jacksonville: 63 mph
Gainesville: 56 mph
Key West: 44 mph

Elsewhere
Valdosta: 57 mph
Albany, GA: 68 mph
Macon: 92 mph
Atlanta: 56 mph
Savannah: 39 mph
Athens: 75 mph
Augusta: 46 mph
Charleston: 37 mph
Columbia: 41 mph
Greenville: 48 mph
Spartanburg: 43 mph
Charlotte: 41 mph
Asheville: 51 mph

A major, potentially catastrophic flooding event possible in the Appalachians

I want to focus on one element of this storm that is now coming into focus and becoming very serious: The risk of significant, possibly catastrophic flash flooding in the Appalachians from north Georgia into North Carolina.

Widespread flash flooding is expected in north Florida and Georgia, but a major, potentially catastrophic flood event is becoming more plausible from northeast Georgia into the western North Carolina mountains, where over a foot of rain is now possible. (NOAA WPC)

A high risk of flooding has been issued for some of those areas by the Weather Prediction Center, which historically has correlated to extensive, significant damage.

A high risk (level 4/4) of flash flooding exists tomorrow north of Metro Atlanta into much of western North Carolina and portions of upstate South Carolina. (NOAA WPC)

This is a historically favorable setup for major rainfall in this region, and there’s no reason to believe this forecast is incorrect. So for anyone in those affected areas and even in the red moderate risk areas surrounding the high risk, it is important to be prepared to take immediate action in the case of flooding or landslides. Please heed the advice of local officials. It is possible that the damage and problems from the inland flooding will be equally as bad as the surge issues at the coast.

Helene is going to be a complex, very difficult storm with multiple different concerns along the way. We’ll keep you posted as best we can through the event, but please also stick with trusted local sources for the latest and most relevant information for your neighborhood. We’ll update this post through the day.

Tropical Storm Helene is beginning to steadily organize in the northwest Caribbean with little forecast change

Changes since this morning

  • PTC 9 became Tropical Storm Helene and its satellite presentation has improved markedly since earlier today.
  • Hurricane Warnings have been issued between Anclote River just north of Clearwater and Mexico Beach in Florida.
  • Storm Surge Warnings have been issued from Flamingo to Indian Pass in Florida, including Tampa Bay and Charlotte Harbor.
  • Tropical Storm Warnings have been issued for the Lower & Middle Florida Keys and the west coast of Florida between Flamingo and the Anclote River, which includes Tampa Bay.
  • Tropical Storm Watches are now posted on the East Coast of Florida and Georgia between the Palm Beach and Martin County line and Savannah River.
(NOAA NHC)

Tropical Storm Helene is slowly getting organized now, as it appears that the wind shear impacting it earlier has leveled off, and it’s feeling the heat of the warm water underneath it. Expect a steady, if not rapid strengthening process to start unfolding soon. SHIPS model guidance indicates rapid intensification risk that is about 8 times climatology over the next 48 hours, not the biggest number we’ve seen in recent years but a very healthy signal that says Helene is going to take off eventually.

Helene’s satellite presentation has improved pretty dramatically today.

The evolution of Helene today from nascent tropical cyclone to organized tropical storm. (College of DuPage)

It now “looks the part” much more than it did earlier. One thing to note is the size of Helene. This is a pretty sprawling storm already, and as it comes north, it will continue to maintain that size, with tropical storm and hurricane force winds extending out farther than we’ve seen with recent Big Bend storms in Florida. According to the NHC’s latest discussion, this storm will be in the 90th percentile of major hurricane size at this latitude. In other words, it’s big, and the winds from Helene will be felt, especially on the east side far away from the center and outside the cone.

An aggressive storm surge forecast continues given the expectation of Helene’s strength and size. (NOAA NHC)

The forecast has changed little since this morning. We still anticipate a major hurricane making landfall in or near the area between the Big Bend and Apalachee Bay in Florida. The size of the storm will complicate the surge potential somewhat on the west coast of Florida, leading to surge values that should be as bad or worse than were experienced in Idalia. We covered that a bit more earlier today.

18z tropical models showing a clustering of weaker outcomes that seem difficult to trust and a clustering of Cat 1 to Cat 3 intensity outcomes. Folks in Florida should be preparing for the higher end to be safe. (Tropical Tidbits)

The intensity forecasts on tropical modeling for Helene have stalled somewhat today, certainly not a bad thing! However, I would be hesitant to read into that too much, as we’ve seen many examples of storms “overachieving” in this part of the Gulf. The biggest question that I have at this point is how close to peak intensity Helene will be when it comes ashore. There is a noteworthy difference between a 115 mph storm making landfall on an upswing versus one that has peaked and is weakening. Idalia was bad enough last year, but it was also past peak and likely less bad than it could have been. Can we pull that off twice? I don’t know, but I know to never trust the Gulf.

More to come tomorrow, and we can hopefully iron out some forecast details farther inland into Georgia and the Carolinas as well.