Delta makes landfall on the Yucatan, next stop Gulf of Mexico

7 am CT Wednesday Update: Good morning. We’ll take a quick look ahead at our forecast for this week and then turn our attention to Hurricane Delta, which made landfall near Puerto Morelos, in the Yucatan Peninsula, around 5:30 am CT today. It had maximum sustained winds of 110 mph. The hurricane will move into the Gulf of Mexico later today.

Wednesday

Today will be warm and sunny, with highs likely climbing into the mid- to upper-80s with light northeasterly winds. We should really start to feel the return of moisture at the surface today, so it will feel a bit more humid, and nighttime temperatures will be a few degrees warmer than Tuesday night, likely not falling below 70 degrees in Houston.

Thursday and Friday

Our weather on both of these days will depend heavily upon how close Hurricane Delta gets to Texas as it moves into the western Gulf of Mexico. In terms of precipitation, for now, we’ll guess (emphasis on guess) the eastern half the region sees perhaps 0.25 to 0.5 inch of rain, with lesser amounts west of Interstate 45. The best rain chances should come on Friday, and partly cloudy skies should help to limit temperatures into the low 80s. Winds may gust up to about 30 mph, or higher, especially on the city’s east side, and along the coast.

NOAA rain accumulation forecast for now through Friday night. (Pivotal Weather)

Saturday, Sunday, and beyond

Some showers may linger into early Saturday, but for the most part, the weekend looks warm and sunny, with highs near 90 degrees. There is the potential for a cold front to arrive on Tuesday or so of next week, but it may get hung up for a few days and not move in until later. Still, we do anticipate more fall-like weather to return in about a week, give or take.

Delta, Delta, Delta

Delta has weakened overnight due to the influence of wind shear at mid-levels of the atmosphere, and it may weaken a little bit further this morning as its center briefly crosses the northeastern corner of the Yucatan Peninsula. As it reaches the southern Gulf of Mexico, the storm should begin to re-intensify tonight, and the National Hurricane Center anticipates Delta briefly pulsing back up to a Category 4 hurricane over the Gulf. (We’ll see).

As the storm moves north it will encounter less favorable conditions and should be on a weakening trend near landfall Friday. Frankly, I have significant questions about how strong Delta will be at landfall, and anything from a Category 1 to Category 3 hurricane seems possible. Most likely, the further east the storm tracks, the stronger it will be.

4am CT Wednesday track forecast for Hurricane Delta. (National Hurricane Center)

In terms of track, our overall thinking has not changed in terms of approaching Texas and then turning north. As you can see in the forecast graphic above, as we get closer to Delta’s Gulf coast landfall, the “cone of uncertainty” in the National Hurricane Center’s official track has narrowed. It now essentially runs from the border between Texas and Louisiana, on the west side, to southeastern Louisiana. This reflects what we’ve been telling you over the last several posts, that the forecast models are generally in quite good agreement on a landfall between the Texas-Louisiana border and Morgan City. Landfall now looks likely to occur some time during the middle of the day on Friday, or during the evening.

Along this track, as noted above, the greater Houston region would only see moderate effects, including increased winds on Thursday and Friday, some decent rain chances, and moderate coastal flooding at high tides. We will need to continue to monitor the storm’s track closely, but the greatest likelihood remains that Delta will be a near-miss for our area.

In terms of Louisiana, Delta’s effects will depend heavily upon its intensity. It does seem really, really cruel that this storm will probably make landfall not too far from where Hurricane Laura did so in August. However, we do think Delta’s winds will probably be less at landfall than Laura, and surge as well. Because the storm is expected to be moving fairly quickly to the north-northeast, rainfall amounts should generally be less than 8 inches for most areas.

Our next post will come no later than 2:45 pm CT.

Delta nearing Yucatan, will move into Gulf on Wednesday

7:40 pm CT Update: Just a quick post this evening on Hurricane Delta. The storm has intensified further since this afternoon, reaching maximum sustained winds of 145 mph at 7pm. However some wind shear in the mid-levels of the atmosphere has lately begun to affect Delta and may prevent further strengthening tonight, or even weaken the storm.

Regardless, Delta will bring devastating winds and storm surge to the Yucatan Peninsula later tonight and on Wednesday. After this time it will enter the Gulf and track west-northwest across the Gulf of Mexico. In terms of what happens after that, not much has changed with respect to the track forecast, which turns Delta north and brings a hurricane to the Gulf coast Friday evening or early Saturday—about three days from now. It seems the most likely location for this landfall will lie somewhere between the Texas-Louisiana border, on the western side, and Morgan City, on the eastern side. Even though we are within three days of landfall, some uncertainty remains, and this is reflected within the National Hurricane Center’s forecast cone.

4pm CT track forecast for Hurricane Delta. (National Hurricane Center)

By tomorrow morning we should have a pretty good sense of the ultimate track forecast for Delta, as the overnight model runs ingest data from today’s aircraft reconnaissance missions as well as supplemental weather balloons to sample the atmosphere helping to control the steering flow for this system. The odds still strongly favor a landfall in southwest or south-central Louisiana, but there is enough uncertainty that we’re going to need to continue to watch Delta closely along the upper Texas coast.

That’s just what we’ll do, of course. In tomorrow morning’s post, which will go up no later than 7:30am, we’ll have the latest on track and potential impacts along the upper Texas coast later this week, as well as Louisiana.

 

Delta rapidly intensifying as it nears Cancun, Gulf of Mexico

2:10pm CT Tuesday: We’re talking about Hurricane Delta this afternoon, which has undergone rapid intensification and is now a powerful Category 4 hurricane with 140 mph winds. (It was only named Delta 30 hours ago.) The storm will approach the Yucatan Peninsula tonight, and likely make landfall somewhere near Cancún early on Wednesday. This will be a dangerous hurricane for that area. By Wednesday evening the storm will be back out over the Gulf of Mexico, moving to the northwest.

Track

Overall, the track forecast remains largely unchanged. The 12z models are beginning to show a tighter cluster of solutions in which Delta moves to the west-northwest, or northwest for most of Wednesday and Thursday. Then, when Delta is a few hundred miles offshore from South Padre Island, it should begin a pretty sharp turn to the north. All of the best available guidance now shows a final landfall between the Texas-Louisiana border—very near where the devastating Hurricane Laura came ashore in August—and further east, around Morgan City and Houma. This tighter clustering of models is consistent with the National Hurricane Center forecast track, and increases our confidence in where Delta is going to go.

National Hurricane Center forecast track for Hurricane Delta at 10am CT.

With that said, we are still roughly three-and-a-half days away from landfall, so the average track error is about 120 miles, and we also have to account for the possibility of wobbles. The bottom line with Delta’s track is that right now every available bit of evidence we have suggests this storm is going to turn toward Louisiana—but its future path is not 100 percent locked down.

Intensity

Delta has had near ideal conditions for strengthening over the last 24 hours, including very warm waters not just at the surface, but also below. This is important because, as the storm moves across the ocean it churns up seas from below, a process known as upwelling, which can bring cooler water to the surface. One measurement of an ocean’s depth of warm waters is its “Tropical Cyclone Heat Potential,” and basically any value of 80 or higher is conducive for intensification. As you can see from a recent map of this potential, the waters in the northwestern Caribbean Sea are explosively warm.

Plot of Tropical Cyclone Heat Potential. (NOAA/AOML)

This will begin to change as Delta moves away from the Southern Gulf of Mexico, at which time the storm also should begin to encounter more wind shear. These factors should help to limit the intensity of Delta as it moves toward the northern Gulf of Mexico, but it remains possible that this system could be a major hurricane at landfall.

Houston effects

Along this track Houston is likely to experience only very mild effects from Delta—perhaps some rain showers on Thursday, Friday or Saturday. Seas will reach their maximum on Friday, but should be below the levels the region experienced during Hurricane Laura.

Needless to say all of this depends upon the storm’s track, and if that changes significantly, so will our local forecast.

Our next update will come no later than 8:30 pm CT.

Hurricane Delta nears Gulf of Mexico, and we’ll need to watch the system

Good morning. The near term weather forecast for Houston will see more sunshine, and increasingly warm temperatures. Later this week our weather may, or may not, be affected to some extent by Hurricane Delta—which should become a major hurricane and move into the Gulf of Mexico. It will be discussed in depth.

Tuesday

Under the influence of high pressure, Houston will see sunny skies, with highs rising into the mid-80s or so, along with a slight northeasterly wind. We should squeeze out one more reasonably cool evening on Tuesday night, with lows sliding down to around 60 degrees for inland areas, and increasingly warmer conditions toward the coast.

Wednesday

Expect temperatures to be a degree or two warmer on Wednesday, with more sunny skies. Lows Wednesday night will be several degrees warmer, possibly not falling below 70 degrees in the city and points southward.

Thursday, Friday, and beyond

Our weather for these days will be determined by the track of Hurricane Delta, which remains somewhat uncertain. For now we’d expect a modest increase in rain chances on Thursday and Friday before mostly sunny and warm conditions this weekend, with highs of around 90 degrees. But we need to see what Delta does.

Hurricane Delta

Two things have happened during the last 24 hours that have moderately raised our concerns with regard to Delta and Houston. One, the storm has rapidly intensified, reaching sustained winds of 100 mph. It is expected to become a major hurricane before landfall. And two, there has been a westward drift in the forecast models that may bring the storm closer to Texas than anticipated. Let’s start with the track.

National Hurricane Center track forecast for Delta as of 4am CT Tuesday.

The National Hurricane Center track has shifted slightly west in response to the models, but remains centered on Louisiana. And in looking at the latest model guidance this morning, the general westward trend in the models seems to have stopped, so the current track seems reasonably on point.

Along this track we expect a major hurricane to come ashore the Yucatan Peninsula on Wednesday, with strong winds becoming a real problem for areas including Cancun. After this time the storm will move northwest across the Gulf of Mexico—toward Texas. The storm will be steered by high pressure over Florida and the Southeastern United States.

However, global models suggest this ridge will weaken this week, allowing Delta to being turning more toward the north by Thursday, bringing the hurricane to the northern Gulf coast by late Friday or early Saturday. Along this track, impacts from the storm will remain to the along the coast, in terms of swells, and to east of the greater Houston region. However, it’s going to be a fairly close thing as some models bring the storm pretty close to Texas before it turns. The National Hurricane Center track is in good agreement with the GFS model ensembles (shown below), which handled Hurricane Laura well earlier this year.

00z GFS model ensemble forecast for track of Hurricane Delta. (Weather Bell)

The National Hurricane Center forecasters suggest there may be a westward bias in the European model ensembles (shown below) that brings Delta the closest to Texas, like we saw with Hurricane Laura. This seems plausible, as the European model is west of most of the rest of the forecast models. For what it’s worth, I agree with this idea. The bottom line is that we’re going to need to keep close tabs on Delta to make sure it makes that turn, even if we’re reasonably confident it will turn. Needless to say, along the official forecast track, a strong hurricane coming to Louisiana after Hurricane Laura and other systems this year would make for an unwelcome mess.

00z European model track guidance for Hurricane Delta. (Weather Bell)

Intensity

In terms of intensity, Delta has continued to deepen this morning in response to extremely warm waters and low shear. It will find similar conditions in the southern Gulf of Mexico before increasing wind shear later this week in the northern Gulf, and cooler waters closer to land, should lead to a weakening trend as it approaches land.

The bottom line is that we’re going to have to keep a close eye on Delta for a few days, as it is likely to be a fairly close call for Texas. Our next update will be posted no later than 2:30pm CT today.