Good morning. Ida has finally weakened into a tropical storm this morning, and is now slowly, at a rate of about 8 mph, moving away from Southern Louisiana. Much of the region is submerged under storm surge and very heavy rainfall. More than 1 million customers in the state, affecting about half of the state’s population, are without power today. Some will be without power for many weeks. Ida, in short, has left a sobering trail of destruction and misery in its wake. We must help our neighbors, and here are some ways to do that right now.

Monday

Today will be hot and sunny, with only a slight chance of showers and thunderstorms. Highs will likely reach the upper 90s. As Ida pulls away from Louisiana, winds will be out of the north and northwest locally, at about 5 to 10 mph, and the overall flow will draw warm air into the region. Rain chances will be down to around 10 percent. Overnight lows will be around 80 degrees.

Tuesday

This will be a similar day to Monday, albeit with slightly higher chances of rain showers, perhaps on the order of 20 percent.

Wednesday and Thursday

Low pressure aloft will bring a modest increase to rain chances by the middle of the week, perhaps about 40 percent for areas south of Interstate 10, and less to the north, and this should also cool temperatures down into the mid-90s. Skies should otherwise be mostly sunny with warm and partly cloudy nights.

Friday, Saturday, and Sunday

While the weekend forecast is not yet locked in, the greatest likelihood is that we see hot and sunny weather, with highs in the mid-90s. As some slightly drier air mixes in, overnight lows may drop into the mid-70s. While not “nice” this definitely would be more pleasant than sultry nights around 80 degrees. Overall rain chances look low this weekend, probably below 20 percent each day.

Tropics

With Ida inland, and an inconsequential tropical depression in the open Atlantic Ocean, what else is there for us to worry ourselves about? The primary area to watch is the southern Caribbean Sea where conditions are somewhat favorable for a tropical depression to develop later this week. The National Hurricane Center gives this area a 20 percent chance of development.

This system is likely to approach Central America or the Yucatan Peninsula later this week, and if it survives interactions with land—which is far from certain—something may eventually move into the Gulf of Mexico. However there is no strong signal in the global models that this will happen, and if it does, there’s little indication it will eventually track toward the upper Texas coast. So while this is something we’re watching, it’s not something we’re particularly concerned about. As for the disturbance moving off of Africa (red X in the map above), it has a high chance of developing but is likely a fish storm that will not bother and landmasses.

Hurricane Ida has rapidly intensified overnight, seeing a steep pressure fall and maximum winds increasing to 150 mph. Very nearly a Category 5 hurricane, Ida should reach the southern coast of Louisiana, about 50 miles due south of New Orleans, around Noon today.

This will be the most devastating hurricane to hit the region since Katrina, 16 years ago today. For some areas, in some ways, it will be worse. The eyewall of the storm will pass very near to the New Orleans metro area. Hurricane-force winds extend across a 70-mile diameter.

Over the next 24 hours parts of Southeastern Louisiana will experience sustained winds well above 120 mph with higher gusts, 15 to 20 inches of rainfall, and a storm surge of 12 to 15 feet. For the New Orleans area, the winds and rainfall should be significantly greater than experienced during Katrina, although the surge should be less. This storm will offer a stiff test of the levee system built after Katrina struck the below sea-level region in 2005.

Ida will be barreling into a low-lying, swampy part of the U.S. Gulf Coast. The storm surge will move easily over this region for miles. While parts of the coast of sparsely populated, there is also major infrastructure in harm’s way. Jeff Masters and Bob Henson have an excellent rundown of damages this region experienced during Katrina, including a complete shutdown to the Port of New Orleans and weeks of delayed barge traffic. Impacts will be similarly severe this time around. Food and fuel prices should rise across the country.

There is no way to sugarcoat this situation. For those who survive, months of misery await the inhabitants of Southeastern Louisiana. Normally recovery efforts are led in Louisiana out of Baton Rouge, the state capital, which is about 100 miles inland. However, Ida is forecast to pass just east of Baton Rouge, with sustained winds of 100 mph. It seems very probable that Ida will knock out power along the entirety of the region’s most populated core, from New Orleans to Baton Rouge. The state—which has one of the worst COVID-19 outbreaks in the country, and nearly 500 patients in ventilators—will lose much of its ability to function. This is just an exceptionally grim situation.

As a forecaster there is not much else to say. The storm is here, and it is a gut punch. Ida is a nightmare scenario for the state of Louisiana. We must stand ready to help them survive, recover, and rebuild.

Good Saturday morning. Ida is strengthening steadily this morning as it moves into the heart of the exceptionally warm Gulf waters between Cuba and Louisiana. Not much has changed since yesterday in terms of the forecast track or, unfortunately, forecast intensity.

If you look at the satellite loop above, Hurricane Ida’s eye is emerging, indicated by the little green “dot” in the middle of the storm, an indication that the system is strengthening.

Unfortunately, very little has changed since yesterday. The track is essentially unchanged, with the National Hurricane Center predicting a track toward Morgan City, LA, with a little wiggle room on either side.

The intensity forecast is mostly unchanged as well, with modeling implying that a major (category 3 or 4) hurricane is almost certainly going to be what makes landfall. At this point, folks along the eastern Louisiana coast should be preparing for significant hurricane impacts.

Storm surge values are mostly unchanged today too,

A significant 10 to 15 foot surge is possible between Morgan City, Grand Isle, and the mouth of the Mississippi River. Slightly lower values can be expected just southeast of New Orleans. It is tempting to compare Ida with Katrina, but there are a number of differences from track to intensity to size. For New Orleans, in Katrina, winds were out of the east and then out of the north. With Ida, winds will be out of the southeast most of the time, which means different impacts this time around. Hopefully far less severe, particularly given the distance of landfall from the city. But it’s obviously much too close for comfort.

In addition to the wind and surge, as we’ve noted Ida will have a ton of moisture as it comes ashore. This will lead to significant rainfall and probably freshwater flooding issues all across eastern Louisiana and Mississippi.

Maximum totals of 10 to 15 inches will be possible along and east of where Ida comes ashore, leading to significant flash flooding and river and bayou flooding in eastern Louisiana. Significant flash flooding issues will likely continue as Ida lifts north into Mississippi as well.

All in all, Ida will be a very, very serious storm for our neighbors to the east, and our thoughts are with them.

Local update

Just a quick local update for the weekend. Scattered showers or thunderstorms will be possible today. We expect coverage to diminish tomorrow, so less chance of rain. And even less chance of rain is with us on Monday. Look for temperatures in the low-90s today and mid-90s tomorrow. Mid, if not upper-90s will be possible on Monday. Winds here should be out of the north or west after tomorrow and be no worse than 10 to 15 mph or so. Some minor runup is possible along the coast with rough surf and strong rip currents, so exercise caution if you’ll be swimming tomorrow or Monday.

Barring any significant changes with Ida, Eric will have our next update on Sunday morning.

Hurricane Ida has strengthened significantly today, going from barely tropical storm status to a Category 1 hurricane with 80-mph sustained winds. Unfortunately, there is little to inhibit further strengthening this weekend. After Ida moves across Cuba tonight, the combination of low wind shear, a moist atmosphere, and blazing hot Gulf of Mexico sea temperatures are ideal for rapid intensification. For this reason, the latest National Hurricane Center forecast brings Ida to a Category 4 major hurricane before landfall along the central Louisiana coast on Sunday afternoon. Confidence is very high in this track.

This post will address what such a storm will actually mean for people on the ground. First up is a forecast for “wind gusts.” This is different than sustained winds, which are how forecaster define the intensity of a storm. But gusts are an appropriate measure of maximum winds. Here’s a forecast for the swath of highest gusts from Ida. It is not gospel, but it offers a good approximation of what to expect, where. There will be major structure damage and widespread power outages.

The next threat from a hurricane like Ida is storm surge. The graphic below from the National Hurricane Center is the best estimate for the combination of surge and tide above normal water levels. Ida will bring a dangerous storm surge to the Mississippi River delta area, and parts of New Orleans not behind the levee system.

The final major threat from a hurricane like Ida is inland rainfall. The storm is going to keep moving, but it will slow a little as it approaches the coast and moves inland. This should allow for some areas of southeastern Louisiana to experience 10 to 20 inches of rainfall, which will be falling on top of a significant storm surge. These are dangerous amounts of water for unprotected areas.

There is not much of a silver lining for this storm, which is set up to deliver a gut punch to the state of Louisiana. The only thing we can offer is that the western part of the state—including Lake Charles—that was pummeled during the 2020 hurricane season should escape the worst of Ida. After this storm moves away from New Orleans later on Monday and Tuesday it will be time to help. That is something the generous people of Houston are very good at.

Matt or I will have an update on Saturday before noon.