Afternoon Hurricane Dorian update—uncertainty abounds for Florida

We’ve had a lot of requests from out-of-state readers to continue providing our perspective on Hurricane Dorian—which threatens to make landfall in Florida as a major hurricane in three or four days time. To be clear, there is absolutely no threat to Houston or Texas.

As of 4pm CT on Thursday, Dorian had maximum sustained winds of 85mph, but based upon its satellite appearance it appears likely to undergo a bout of intensification soon. It will likely become a major hurricane within 24 hour, and then should experience more or less favorable atmospheric conditions for further intensification for several days as it passes north of the Bahamas and turns west toward Florida.

In looking at this afternoon’s weather model data, what is particular striking to me is the high degree of uncertainty about where Dorian is going to go by Sunday or Monday. There is, in fact, no guarantee it will even hit Florida. There is a non-zero chance it goes south of Miami, or turns north before reaching the Florida peninsula. A little while ago, I wrote a story for Ars Technica about this uncertainty, which is highlighted in this afternoon’s ensemble output from the European forecast model:

Five-day ensemble forecasts for Hurricane Dorian’s track. (Weathernerds.org)

If you click the image above to enlarge it, the following explanation will probably be more clear. In any case, this plot shows the track of Dorian out to 120 hours, so that means its position as of Tuesday at 7am CT. Notice that there is a remarkable variance in the location of the “center” of Dorian in these roughly four dozen ensemble members. Yes, a reasonable amount of the ensemble members bring Dorian to the coast between Sunday and Tuesday, but some are far, far away. In some scenarios, Dorian turns north before even reaching Florida. This is reflective of the fact that steering currents for the storm are likely to become extremely weak by Saturday or so.

The 4pm CT Thursday track forecast from the National Hurricane Center captures this ambiguity. It encompasses the entire Florida peninsula within the five-day cone of uncertainty.

4pm CT Thursday track forecast from the National Hurricane Center.

This is singularly unhelpful to the residents of the Sunshine State, who are staring down at the possibility of a major hurricane making landfall somewhere along the peninsula in three to four days. The time for preparations and evacuations is now, but it is hard to offer much in the way of specificity about where the worst storm surge, damaging winds, and inland rainfall will occur. Certainly a slow-moving storm will make the latter variable, rainfall, worse.

Matt and I will continue coverage of the storm through the Labor Day Weekend.

Summer rambles on for Texas, Dorian coming for Florida

On Wednesday, for Houston’s now-daily game of rainfall roulette, the Inner Loop area of the city generally “won” the contest with 2 to 3 inches of rainfall. Meanwhile, most of the suburbs were dry, or saw only a few raindrops. This pattern will likely continue through the work week, although the intensity of storms today and Friday hopefully won’t be quite so high.

Thursday

Today will be hot and mostly sunny, with high temperatures in the mid-90s. We’ll see our usual ramp up in storm activity this afternoon, but high-resolution models indicate that storms won’t be as widespread or as intense as Wednesday. As usual, storms should wane with the loss of daytime heating, and nighttime temperatures probably won’t fall much below 80.

Rain chances on Thursday will be a little better along the coast. (Pivotal Weather)

Friday

Another day like Thursday, although rain chances may take another step backward, with perhaps only 20 percent coverage during the afternoon and early evening hours.

Saturday and Sunday

Drier air from a dying front should make for a pretty nice—all things considered—Labor Day Weekend. Expect high temperatures in the mid-90s, with mostly sunny skies. Lows at night may get into the mid-70s for central and northern parts of the metro area, so mornings and evenings may be a smidge more pleasant than we’ve seen. Finally, rain chances will be very low.

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Showers possible through the week, keeping an eye on the tropics

Good morning. Most of the area remained dry on Tuesday, but there were some sneaky strong showers and thunderstorms in the Clear Lake area that dropped as much as 2-3 inches of rain over a few locations during the afternoon—a good reminder of August’s potential to produce a lot of rainfall quickly in Houston. We’ll fall into a moderately more wet pattern before the weekend dries out. This post will also looks into the tropics, which continue to remain active.

Wednesday

High-resolution models show scattered, but fairly strong showers and thunderstorms developing over parts of the metro area this afternoon and evening. I think the pattern will be similar to that on Tuesday, where a few areas see quite a bit of rain, but most of the region sees a tenth of an inch or less. The day will otherwise be partly sunny, with highs in the mid-90s.

Rain accumulation forecast for Wednesday. (Pivotal Weather)

Thursday and Friday

The pattern will be more or less the same to end the work week, with a dissipating cool front providing an impetus for scattered showers and thunderstorms. Rain chances will be about 40 percent each day. The front won’t have much effect on temperatures, with highs generally in the mid-90s, although lows may fall a few degrees into the upper 70s. So it goes in August.

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Hot in Houston, and heating up in the tropics

Summer continues apace this week—for the love of God, is August over yet??—with not much overall change in the forecast. We can expect highs in the upper 90s and lows around 80. Some drier air this weekend may help with nighttime temperatures, but we’re making no promises. We’ll also discuss the tropics in today’s post because it’s that time of year, and the Gulf may see some activity over the next week or so.

Tuesday

We’ll start today with mostly sunny skies, and highs are going to pretty quickly leap up into the mid- or upper-90s. However, it appears as though the sea breeze may be a little more active this afternoon than Monday, with scattered thunderstorms popping in the 2pm-6pm range this afternoon.

Wednesday and Thursday

These should be typical summertime days in Houston, with highs in the upper-90s, and afternoon shower and thunderstorm chances in the 30 percent range. Nights remain warm and sultry and unpleasant.

Monday afternoon dewpoint forecast from the GFS. (Weather Bell)

Labor Day Weekend

If you have outdoor plans, I hope you have included some water in those plans. Yes, a very weak front will approach the region and may reach Houston this weekend. But no, it’s not going to bring much cooling. If you’re far enough west or north of Houston, you may possibly see some dewpoints in the lower 60s or upper 50s on Sunday and Monday, but right now we don’t think this will be all that noticeable in Houston.

For the most part, we’re going to see highs in the upper 90s, mostly sunny skies, and rain chances of 10 to 20 percent each day.

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