Ex-Hurricane, now Tropical Storm Helene is causing a historic flood event this morning all across the Southeast. I count no less than 10 flash flood emergencies as I write this between Georgia and the Carolinas. These include Atlanta, Charlotte, and Asheville.
Data from NSSL’s MRMS shows significant flooding risk in Metro Atlanta this morning, hence the flash flood emergencies there. (NOAA NSSL)
Severe flooding is also occurring in Upstate South Carolina and areas from Charlotte west into the mountains in North Carolina, including Asheville. (NOAA NSSL)
I don’t recall the last time I saw 10 flash flood emergencies at once. Suffice to say it can probably be counted on one hand or less.
A “high” risk (level 4/4) for flooding remains in effect today in western North Carolina. It’s surrounded by a moderate risk. all the way into extreme southern West Virginia. A second area of moderate risk exists just west of Nashville. High risks correlate strongly to the worst flooding outcomes in terms of damage and loss of life, so much like yesterday and overnight, this will be a rough stretch.
A high risk (level 4/4) for flooding is posted for the North Carolina mountains, with moderate risks around that into the Virginias and a second moderate risk just west of Nashville. (Pivotal Weather)
Conditions should improve in Atlanta today, but the damage is done. Asheville remains at risk, as do locations up through Roanoke through Virginia.
Additional rainfall of 4 to 6 inches with locally higher amounts should be expected in the North Carolina mountains and in portions of Tennessee. (NOAA WPC)
Meanwhile, winds continue gusting in excess of 50 and 60 mph all across South Carolina with even some 70 mph gusts too in North Carolina. Power outages are up to about 3.5 million between Florida and Virginia. Those numbers may continue to increase a bit more. The hope is that the low pressure center of Helene will slowly lose identity and weaken by later today and tonight. Flooding risks should drop off heading into tomorrow, though isolated flooding will be possible north and west of the hardest hit areas, perhaps into southern Indiana or Kentucky.
I have not had time to dig through reports from the Florida coast, but I know that it will take time for the worst surge reports to emerge. It always does. And we will almost certainly see the NHC forecasts of 15 to 20 feet verify. The Tampa area broke all their surge records yesterday by a wide margin. This was far and away the worst modern storm to hit the northern west coast and Big Bend area of Florida. More on this to come.
Other news and notes
We’ve neglected other things this week for obvious reasons. Here’s just a quick rundown of what else is happening. More to come on this.
Tropical Storm Isaac formed and was upgraded to a hurricane today. It is headed out to sea.
Isaac. (NOAA NHC)
Invest 98L, also in the deep, open Atlantic has a good chance to be upgraded to a depression or Tropical Storm Joyce later today. It is no threat to land.
Invest 98L could become a depression or tropical storm today. (Weathernerds.org)
The NHC dropped an area of interest yesterday in the Caribbean in a very similar spot to where Helene was conceived. It has a 30% chance of developing over the next week.
A 30% chance of development exists in the northwest Caribbean or near the Yucatan — again over the next week. (NOAA NHC)
This Caribbean or Yucatan area does not currently have the same degree of model support we saw at this point from Helene for something high-end. However, there is a substantial signal for something in the region next week. We’ll have more on this later in the weekend. For now, don’t worry about it but check back in for updates.
We will post again later today with an update on Helene and anything else of note.
Hurricane Helene is about to make landfall by midnight, likely in Taylor County, FL, just south of Perry in the Big Bend as at least a 140 mph category 4 monster of a storm. There are too many superlatives to cover right now between the surge and wind and flooding and tornadoes. But suffice to say that Helene is en route to retirement in all likelihood.
Hurricane Helene on approach to Taylor County, FL. (RadarScope)
Historic water level values have all been met or broken in Tampa Bay.
(@WeatherProf on Twitter/X, Jeff Beradelli from WFLA Tampa)
Widespread rain is causing flash flooding all over the Southeast that will worsen overnight.
Estimated rainfall is in excess of a foot in Florida and 8 to 10 inches on the NC/SC/GA border area. (NOAA NSSL MRMS)
Tornado Watches blanket much of the Southeast and numerous tornado warnings have occurred today. And an extreme wind warning is in effect just east of Tallahassee, the rarest of warnings reserved for only the mightiest of landfalling hurricanes. Helene joins that club shortly.
There have been no changes of note to the storm track, but the potential for stronger winds inland has expanded somewhat through the day today, and the wind risk map now looks like this:
Extreme hurricane winds are likely in south Georgia, slowly slowing down in central Georgia, though significant tropical storm winds are expected across much of North Georgia, southern South Carolina, and the Smokies. (NOAA/NWS, Google Earth)
This is likely to cause significant, long-duration power outages in Georgia and the Carolinas in addition to the anticipated widespread, severe, potentially catastrophic flash flooding. This includes the Atlanta metro. Charge your phones now if you have not already.
We’ll continue to watch this tonight and have a complete update later or in the morning.
(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.
(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.
