NHC put Isaias at 105 mph at landfall near Destin. Here is what the shear did, how the outcome compares with our 5 October piece, and why one hurricane does not undo a quiet El Niño season.
Hurricane Isaias came ashore near Destin, Florida, at 0130 UTC on 10 October, which was 8:30 PM CDT Friday. NHC’s landfall update had maximum sustained winds of 105 mph, a Category 2. NHC’s other products for that hour differ a little: a corrected update half an hour later said 100 mph, and Discussion 14 said 90 knots, about 104 mph. All three are Category 2, and the post-storm review can still revise the operational estimate. The storm follows our 5 October piece on the Gulf disturbance, and it is the kind of outcome a strong El Niño year makes less likely, not impossible.
It also ended a hurricane-free stretch that had lasted the whole season until 8 October. The question is not whether one landfall breaks the story. It is what the story was claiming in the first place.
Everything below comes from NHC’s own advisories and discussions, read on the morning of 10 October.
| When (CDT) | NHC product | Status and winds |
|---|---|---|
| Tue 6 Oct, 4 PM | Advisory 1 | Tropical Depression Nine forms in the Gulf, 35 mph |
| Wed 7 Oct, 4 AM | Advisory 3 | Named Tropical Storm Isaias, 40 mph, 1004 mb |
| Wed 7 Oct, 4 PM | Advisory 5 | 65 mph, 994 mb, described as rapidly strengthening |
| Wed 7 Oct, 10:30 PM | Update (0330 UTC) | Upgraded to a hurricane, 75 mph, 982 mb |
| Thu 8 Oct, 4 PM | Advisory 9 | 100 mph, 975 mb |
| Fri 9 Oct, 4 AM | Advisory 11 | 110 mph, 963 mb |
| Fri 9 Oct, 10 AM | Discussion 12 | Estimated 105 kt (120 mph), 959 mb, a major hurricane |
| Fri 9 Oct, 7 PM | Advisory 13A | 110 mph, 967 mb, landfall expected within one to two hours |
| Fri 9 Oct, 8:30 PM (0130 UTC) | Update | Landfall near Destin, 105 mph, 971 mb |
| Fri 9 Oct, 9 PM | Update (corrected) | 100 mph, 978 mb, center about 50 miles east of Pensacola |
| Fri 9 Oct, landfall at 0130 UTC | Discussion 14 | Landfall near Destin assessed at 90 kt, about 104 mph |
| Fri 9 Oct, 10 PM | Advisory 14 | 90 mph, 982 mb, over the western Florida Panhandle |
| Sat 10 Oct, 1 AM | Advisory 14A | Post-tropical over southern Alabama, 65 mph |
| Sat 10 Oct, 4 AM | Advisory 15 | Post-tropical, 35 mph, final NHC advisory |
Two things stand out. Isaias went from 40 mph at 4 AM Wednesday to 80 mph at 4 AM Thursday. That is 35 knots in a day by our arithmetic from advisories 3 and 7, past the usual 30-knot yardstick for rapid intensification, though NHC’s advisory did not use that term. And the hurricane upgrade came at 0330 UTC on 8 October. NWS Tallahassee’s newsletter gives 8 October 1905 as the latest first Atlantic hurricane of a season on record. Isaias became a hurricane on 8 October by UTC, so it sits at the edge of that date. We do not have the 1905 onset time, so we do not claim a tie or a record.
On Thursday morning NHC had about 20 knots of westerly shear tilting the storm, expected the shear to jump to 40 to 50 knots before landfall, and forecast 95 knots 24 hours out. That verified: advisory 11 on Friday morning was 95 knots. Then Isaias kept going to an estimated 105 knots by 10 AM Friday.
From there the shear did its work. NHC measured 30 to 40 knots from the southwest, a little less than it feared. At 10 AM the shear was nearly aligned with the storm’s motion, which limited how much it could weaken the storm at that hour. By 4 PM NHC called it the main reason for weakening: the circulation tilted with height, convection sat mostly in the northern eyewall, and dropsondes showed winds falling sharply near the surface. Isaias lost about 15 knots, roughly 17 mph, in the ten and a half hours to landfall.
So the shear trimmed a major hurricane down to Category 2 and did not stop it. What it cannot tell us is how much of that shear was El Niño’s. The NHC products we read do not attribute it to El Niño, and neither can this post.
Our 5 October piece sorted what was observed, forecast and unresolved. Here is how each held up.
| What our 5 October piece said | What happened |
|---|---|
| NHC gave the area 60% over 48 hours and 80% over seven days, with a depression expected midweek. Our Friday and 12 October checkpoints asked whether it would form. | Formed as Tropical Depression Nine at 4 PM CDT Tuesday 6 October and was named Isaias early Wednesday. The formation checkpoint was met. |
| NHC text: drift east for a couple of days, then north. Models were "all over the place." | East at about 5 mph on the 6th, east-northeast near 9 mph through the 8th, then north-northeast and north at 15 to 20 mph, ending at Destin. |
| Strength unresolved. The outlook went no further than a depression, and we forecast nothing stronger. | Hurricane at 0330 UTC on 8 October, an estimated 105 kt peak on 9 October, 105 mph at landfall in NHC’s landfall update (90 kt in Discussion 14). |
| Fox Weather reported upper-level winds across the northern Gulf as extremely hostile. We could not say how much was El Niño’s. | About 20 kt of shear on Thursday, 30 to 40 kt on Friday. It trimmed the storm and did not prevent a Category 2 landfall. Still no attribution to El Niño. |
| WPC had a Marginal Risk for excessive rain on the central Gulf Coast, with local press totals of 5 to 7 inches. | NHC’s Friday night forecast was 4 to 8 inches, with up to 15 locally. We have not read observed totals. |
No, and the reason is in the wording of the story. NOAA’s AOML says El Niño generally lessens Atlantic activity by raising vertical wind shear, with the effect strongest from September to November. NOAA’s 21 May 2026 seasonal outlook, which expected El Niño to strengthen, put this season’s odds at 55% below normal, 35% near normal and 10% above normal. Those are that outlook’s probabilities for 2026, not general odds for every El Niño year. The same release says the outlook is not a landfall forecast, and NWS Director Ken Graham noted that one storm can make a bad season. A shifted distribution is not a ban.
The tally still looked like a quiet year before Isaias peaked. NHC’s table as of 21 UTC on 8 October lists nine named storms (two below the 1991 to 2020 normal), one hurricane (four below), no major hurricanes (two below) and ACE of 13.2, which NHC puts 87% below that normal. That table predates Isaias at its peak, so the major-hurricane count and ACE will both rise. We have not calculated how far, and we are not putting a number on the new total until NHC updates its table.
Meanwhile NHC’s page this morning has Hurricane Simon at 145 mph off southwestern Mexico and Tropical Storm Rachel in the eastern Pacific, the side El Niño tends to favor, as our Pacific-side piece covered. Two storms do not prove a link. CPC’s 8 October discussion has El Niño still strengthening, with an 83% chance of a historic October to December event, which we cover in our WMO forecast piece.
Isaias has weakened sharply, but gusty winds and flooding remain threats, and the water is the larger one. NHC’s last advisories forecast 4 to 8 inches of rain across southern Alabama, the Florida Panhandle, the Big Bend and southwest Georgia through the weekend, with local totals up to 15 inches, and 2 to 5 inches across much of the rest of the Southeast, with up to 10 inches in the Southern Appalachians and coastal Carolinas. NHC expects flash, urban and river flooding, considerable flash flooding and landslides in the Southern Appalachians, tornadoes across parts of the Panhandle, Georgia and the Carolinas on Saturday, and life-threatening surf along Gulf coasts. NHC’s final discussion still noted a risk of some high wind gusts over the southern Appalachians. By 4 AM CDT the storm surge warnings had been discontinued and NHC said water levels were receding along the Florida Gulf coast.
NHC’s final advisory at 4 AM CDT had Isaias post-tropical at 35 mph near Montgomery, and NHC said the Weather Prediction Center is scheduled to take over at 10 AM CDT. We have not read WPC’s products, observed rainfall, measured surge, damage or casualty reports. NHC’s season table, as of before landfall, lists no deaths and no U.S. damage, which says nothing about now.