Tracking a cool front, and a developing tropical system in the Gulf

Good morning. We’re continuing to anticipate the arrival of a cool front late on Friday or Saturday morning, which should make for a rather pleasant early fall weekend across the region. It won’t exactly be cold, but it sure will be less humid. Meanwhile, we’re also anticipating the formation of a tropical storm or depression in the Southern Gulf of Mexico fairly soon—this will have to be watched closely but the forecast for now mostly keeps inclement weather out of the Houston region. More on this below.

Thursday

The really hot weather is almost over, we promise. And it has been hot. Both Hobby Airport and Galveston again tied heat records on Wednesday with highs of 96 degrees. Temperatures should be about 5 degrees cooler today with partly cloudy skies, and rain chances of 30 percent or so. These rain chances will be driven by an upper-level low pressure system and enhanced by daytime heating. Low temperatures tonight will be in the mid-70s for most.

Friday and Friday night

Friday should be similar to Thursday in terms of sensible weather, but things should begin to change late Friday night or Saturday morning. As Matt wrote yesterday, this will not be a knock-you-off-your-feet front blowing in from the northwest, but rather over the weekend we’ll gradually see drier air moving in. This should become noticeable on Saturday morning.

Temperature change forecast for Saturday morning, at 3am CT, shows cooler air moving in. (Weather Bell)

Saturday and Sunday

This will leave us with a pleasant weekend. Right now I’d peg highs in the upper 80s, with mostly sunny skies, for most of us. With lower dewpoints, these temperatures will feel much more comfortable. Low temperatures should get into the mid- to upper-60s on Saturday and Sunday mornings, except for the coast, which will stay a bit warmer. So clearly not cold, but after months and months of summer, the difference in humidity will be notable. Enjoy this taste of fall for a few days Houston, you’ve earned it.

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Friday front still on the way, keeping Gulf tropical shenanigans away from us for now

We’ve got a lot of moving parts in the forecast for the next week or so, with each one helping shape what the next one will do. The first big item is our late week front, which seems to be on track. The second item is the tropical disturbance off Mexico that many of you have expressed interest or concerns in, so we’ll explain how those two interact and what it could mean.

Today

Wednesday should be a sunny, hot day. We should see at least a few showers and storms crop up, perhaps more likely north and west of Houston. But I think most of us will be dry. Look for highs in the low- to mid-90s area-wide.

Thursday

For tomorrow, a disturbance in the upper atmosphere is going to approach southeast Texas. We should see more cloud cover Thursday, and we may even have showers in the area by sunrise. As the day goes on, we’ll call it partly to mostly cloudy with scattered thunderstorms developing. After a morning low in the muggy 70s, look for highs in the low-90s or a touch cooler north and west.

Friday to Sunday and cold front

Last week’s cold front was an “in your face” type of frontal passage, where once the front passed your backyard, you knew it was there. I’m not sure this next front will be quite like that. Look for perhaps some showers Thursday night and Friday morning. They’ll drop south on Friday and any more organized storms should focus south of I-10 to the coast before dissipating late. The front itself will lag a bit, but it is expected to pass the northern half of the area Friday morning and afternoon, and it should eventually reach the coast by Friday night or early Saturday. Instead of a sharp change, we will likely see a gradual drop in humidity and clearing later Friday into Saturday.

Yes, Saturday morning should see low temperatures in the 60s away from the city and the coast. (Weather Bell)

Look for Friday morning lows in the 70s still, followed by highs near 90° Friday afternoon. Then on Saturday, look for morning lows in the 60s in suburbs and outlying parts of the area to around 70 in Houston and mid- to upper-70s along the coast. Sunday morning should be similar.

Both Saturday and Sunday look like fine early autumn or late summer days with ample sunshine. A few morning clouds are possible Saturday south of Houston. We will still see highs in the upper-80s to near 90°, but the humidity will be tolerable.

Can the front fail? It’s plausible that the front doesn’t push quite as aggressively offshore, but trends since yesterday have been toward a slightly stronger push and the front basically dissolving 100 to 200 miles offshore. So we think that this is real.

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Eye on the Tropics: No Vacancy

The Atlantic is full. No room at the inn, folks. We’re fresh out of vacancy. If only that were true. Since our last tropical update last Tuesday, we’ve added <checks notes> three more storms. We’re running about three weeks ahead of 2005’s pace and the last name on the list is Wilfred before we shift over to the Greek alphabet. You can argue all day about how many of the storms have been minimal, but a storm is a storm and 2020 is certainly in a unique place based on our historical records. Incidentally, if you want to look back at an interesting analog year to this one, check out 1971.

It was also a year full of mostly minor to moderate storms, including Fern in South Texas and Edith near Cameron, LA. But it included six active systems (including Fern & Edith) at once with one additional in the pipeline. Ginger on that map above is noteworthy for being the longest lived modern Atlantic tropical system. It lasted from September 10th through October 7th, before eventually reaching land in North Carolina. That track map is something to behold. Even better, it was drawn by local hurricane legend Neil Frank.

At present, we are monitoring four systems, none of which are a concern for Houston. There are also two “invests,” neither of which are a serious concern for us either. Plus, we have one “untagged” Gulf disturbance.

There are four active storms, two “invest” areas, and one Gulf disturbance that we’re watching in the Atlantic this week. (Weathernerds.org)

We’ll do our best to sift through the morass for you, starting with that current lineup of storms and then talking the hypothetical systems.

Hurricane Sally

Eric covered Sally earlier today, and not much has changed. Sally remains a category 1 storm with 85 mph winds. It is going to meander just offshore of the Gulf for the next day or so before beginning to move along north and northeast. Water trumps wind in terms of greatest threats with Sally, as persistent onshore flow will keep coastal areas inundated for awhile.

Sally is going to slowly advance north and eventually pick up a little speed as it moves inland, but it will deliver severe flooding to parts of the South. (NOAA)

Meanwhile, heavy rainfall will repeatedly pelt southern Mississippi, Alabama, the Florida Panhandle, and eventually Georgia and the Carolinas leading to widespread and potentially severe flash flooding.

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Summer hangs on for a few more days before a front moves into Houston

Good morning. This post will discuss our rain chances toward the end of the week, a modest cool front this weekend, and also dig into Hurricane Sally, which is nearing the northern Gulf of Mexico coast and will bring devastating flood impacts there.

Tuesday

Today is going to be just plain hot. Most (but not all, I know) readers are dearly looking forward to the end of summer. But we’re not going to find it today, with clear skies and high temperatures pushing up into the mid-90s. We’ll see slight northerly winds on the back side of Sally’s circulation, but it’s going to be just plain humid and summer-like. Overnight temperatures will likely push into the upper 70s across the metro area to low 80s right on the coast. There is a slight chance, perhaps 20 percent, of some afternoon and evening showers to provide some relief.

Wednesday

Wednesday should be a lot like Tuesday—hot, mostly sunny, and with only a slight chance of afternoon showers. If you like summer in Houston, you’re in luck!

Thursday and Friday

The overall pattern begins to change by Wednesday night or so, as an atmospheric disturbance nears the area. This should allow for the development of some clouds in the sky, and a healthy chance of rain showers. It appears as though rain chances will be highest on the western side of Houston—some areas may see on the order of half an inch of rain, maybe? Temperatures should moderate slightly, into the low 90s, and overnight lows will drop a few degrees as well.

This European model forecast for dewpoints shows the forecast for Friday morning (left) versus Sunday morning. The latter should be quite pleasant. (Weather Bell)

Saturday and Sunday

We’re now pretty confident that some sort of front will push into Houston on Friday night or Saturday morning, but we still don’t have great confidence in the details. At this point it’s probably best to temper expectations. Yes, we’ll see some noticeably drier air. Yes, this should shave a few points of high and low temperatures. But no, at least right now, we can’t definitely say it will feel like fall in Houston. However, the good news is that we don’t expect to go back to highs in the mid-90s and lows near 80 after this front passes. Summer’s days are numbered as we should see more fronts after this one.

Hurricane Sally

Matt will have all the details on an incredibly action-packed tropics in a post later this morning, and you’ll want to be sure and check that out. Regarding Sally, the good news is that the storm not intensified over night, and remains a Category 1 hurricane with 85 mph winds. As wind shear begins to increase, Sally should not get a whole lot stronger over the next 24 hours before it makes landfall. But that’s where the good news ends.

NOAA five-day rainfall outlook for Hurricane Sally. (Pivotal Weather)

Sally is only moving to the northwest at 2 mph. At present the storm remains a few dozen miles east of the mouth of the Mississippi River. Two days from now, on Thursday morning, it should still be over southern Alabama. As anyone who lives in Houston knows, this is a recipe for extremely heavy rainfall. This will occur primarily over southern Mississippi, Alabama, and the Florida Panhandle over the next several days, with isolated totals of 20 inches or more possible. A large swath of heavy rain will then traverse Alabama and northern Georgia along Sally’s eventual track. This will of course lead to devastating flooding.