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Into the teeth of summer - the hot stretch is here

Stephen Uzick
Aug 9, 2019, 6:17 am
Giphy/ The Simpsons

Well we have officially entered the dog days of August - the teeth of our summer. The end of this week and into at least the first part of next week will be the hottest period so far this year as an area of high pressure has parked itself right over Texas. In fact yesterday was the first time this year that the official temperature at Bush Airport (the official recording station for Houston) reached 100 degrees, a mark that could easily be reached a couple of more times over the next week or so.

As we know down here, while the temperatures are hot, it is the humidity that is the real monster, and there will be no shortage of that either. The humidity provides a double kick to the face in these situations since it 1. causes the heat index to soar and 2. prevents the air from cooling down much at night after the sun goes down because moist air takes a lot longer to cool down than dry air. This was evidenced by the fact that early the past couple of mornings, when the temperature should be the lowest, Galveston was recording a heat index of almost 100 degrees because the humidity was absurdly high. Speaking of absurdity look at this tweet from the National Weather Service Yesterday afternoon:


WUT?!?Twitter NWS Houston

Yes that really says the heat index or "feels like" temperature was 117 degrees at 1 pm yesterday afternoon. The dew point of 81 degrees indicates incredibly humid air on top of temperatures in the mid 90s. Any other time of year a dew point of 81 degrees would be like rocket fuel for thunderstorms, but that area of high pressure I mentioned is keeping a lid on things.

That high pressure, which is an area of sinking air, has anchored itself over Texas and will make our great state the heat bulls-eye for about the next week. So why does high pressure make things so hot? As air sinks from the lower pressure areas of the atmosphere towards the surface it heats up due to friction among air molecules, additionally the sinking air cuts off any lift that would be necessary for rain or cloud cover so we are left with clear skies and abundant summer sunshine. You can really see the effects of this area of high pressure in the two images below. The first is temperatures, the second shows how Texas is basically in a big donut hole when it comes to rain through next week.


Forecast temperatures Saturday afternoon. Heat is centered right over TexasTropicaltidbits.com


Forecast rain amounts thru Tuesday. Most of Texas is bone dryWeathermodels.com

So is there any relief in sight? This "heat dome" wont last forever, but we still have about a month or so of peak summer left. Next time I will share a bit more on what the average dates are of when things start to cool down, so stay tuned.

Finally, a brief word about the tropics:

Dead.

See I told you it would be a brief word.

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The Death Ridge breaks and rain finally returns

weathermodels.com

Last time we spoke the miserable heat wave that has now brought six consecutive days with temperatures at or above 100 degrees was just beginning. While Houston obviously gets hot, this stretch of consecutive days over 100 is fairly uncommon. As bad as the days have been the nights have actually been worse as the sustained daytime heat makes it harder for the air to cool off at night as heat absorbed by the ground, and particularly concrete, during the day continues to be released from the ground at night. I am happy to say though that it appears we are reaching the end of this particular hot streak. Congratulations, you survived.

The area of high pressure, also known as the "Death Ridge," is moving off to the west which will bring in a bit of a northerly wind flow and a weak front. I hesitate to call it a front as it won't change the air-mass much. Rather, it is more of a boundary that could provide a focusing mechanism for some rain. Today and tomorrow will bring us the best chance of rain we have seen in a while, which is sorely needed after the baking we have endured. While I don't think everyone will see rain the next couple of days there should at least be enough rain and clouds around to keep temperatures in the mid 90's instead of over 100.

Rain finally returns. Simulated radar this evening.weathermodels.com

Into the weekend rain chances will go down but not disappear entirely. Instead we will be going back to our more normal summer programming with a few afternoon storms here and there.

How Much More Summer:

Now that we are all thoroughly sick of the heat I decided to take a look to see what the averages say as to how much longer we have to go until things start cooling off. Looking at data from Hobby Airport compiled over the past 70 years I found the following:

  • Average date of last 95+ degree day: September 6th
  • Average date of last 90+ degree day: October 7th
  • Average first date with low temperature of 65 degrees or below: September 18th
  • Average first date with low temperature of 60 degrees or below: September 28th

Keep in mind that these dates are just averages, but it does show that we only have about a month to month and a half left of real summer misery. Yes, heat can sometimes last well into October, but the light is starting to appear at the end of this tunnel, just hold on a little longer.

Hurricane Season Update:

We are entering what is typically the peak of hurricane season but the Atlantic and Gulf are still dead. Part of this is because there is still a good amount of saharan dust out in the Atlantic, indicative of hot dry air in the upper atmosphere which inhibits any potential storm growth. The law of averages would say that things will get churning at some point in the Atlantic Basin over the next month or so but as of now the computer models are not sniffing anything out.

Oranges an reds indicate Saharan dust in the atmosphere over the Atlantic.CIMSS/Univ. Wisconsin

Mailbag:

Since the weather has been quite lately I am opening up the WeatherMap mailbag. Tweet any of your weather related questions to @stephenuzick.

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