Originally published at: Why has it been so hot this month? Also, after a sunny Turkey day comes a soggy weekend – Space City Weather
In brief: Today’s post dives into the very warm Gulf waters, which have been driving this month’s anomalously warm temperatures. We also look ahead to exceptional weather for Thanksgiving and a soggy weekend. Also, I review how that ‘crazy’ long-range holiday forecast I made 12 days ago held up. Am I a turkey?
A November to remember
With less than a week to go in the month of November, the city of Houston’s average high for this month has been 80.3 degrees (normal average high for the month is 72.6 degrees). Now we are going to come down off of this a little, because after today our highs for the remainder of the months will be closer to 70 degrees than 80. But still, it’s been hot. We had 10 days in the middle of the month where every day had a high of 83 degrees, or above.
As always with climate and weather there are no simple answers, but I think one main driver of our anomalously warm November is the Gulf. For much of this month we have had a southerly flown off the water, and that has led to warmer days and nights. Let’s take a look at the current map for sea surface temperature anomaly in the Gulf, which simply means how much warmer (or cooler) the surface is than usual. Note the temperatures in the map below are depicted in Celsius, rather than Fahrenheit.
Surface temperatures right along the shelf of the Gulf, by the Texas and Louisiana coasts, are running 5 to 8 degrees Fahrenheit above normal. That’s really significant, and it helps explain why we’re having trouble cooling down closer to temperatures more typical of this time of year. This heat also extends below the surface. The graphic below depicts “ocean heat content,” which essentially includes measurement of surface and deeper waters in the Gulf.
Now the graphic is a little busy, but essentially the blue line represents “normal” heat content for the last decade, and the bright red line shows what’s happening this year. And the current total heat in the Gulf is higher right now than at any point over the last decade. So there is a lot of hot water out there. I’m sure there are complicated reasons for this, but it is hard to deny that this kind of heat is one consequence of a warming planet. We are finally going to cool down this week on land because the overall flow will shift to come from the north, rather than the south, keeping the warmer air over the Gulf offshore.
Tuesday
After Monday’s storms, quieter conditions have prevailed across the region. Following the passage of a weak front, drier air will slowly seep into the region from the northwest today, bringing gradually falling dewpoints. However there just is not much oomph with this initial front, so most of Houston is likely to see high temperatures in the vicinity of 80 degrees today. In contrast to our usual daytime pattern, highs will likely be a little warmer closer to the coast, whereas areas further inland remain in the upper 70s, more influenced by the front. You’ll notice the lower humidity by this afternoon, and this evening will feel mighty pleasant. Skies will be clear. Lows tonight will drop into the 50s for most.
Wednesday
A secondary push of colder and drier air, this time with more impetus behind it, arrives on Wednesday. This will lead to a day with mostly sunny skies and a high temperature in the neighborhood of 70 degrees. Winds will be gusty in the middle of the day, up to 20 or 25 mph as the northerly air blows in. Our humidity will drop even further, with lows on Wednesday night falling into the 40s for most locations away from the coast.
Thursday
After a chilly start, Thanksgiving will be a beautiful, sunny day with highs generally in the upper 60s and light winds. The National Weather Service, this morning, is actually forecasting a high of 68 degrees at both Bush Intercontinental and Hobby airports. I’m not going to brag—as a forecaster it pays to be humble, because you’re always going to miss some shots—but remember when I made that long-term Thanksgiving forecast 12 days ago? You guessed it, I predicted a high of 68 degrees. I was wrong about the rain chances, they’re not 30 percent, they’re closer to zero. As for the partly cloudy skies predicted then, I would go with mostly sunny instead. Lows on Thursday night will be similar to Wednesday night.
Friday
The onshore flow will kick in Thursday night or Friday morning, and this will set us on a warming curve. Friday will be partly to mostly cloudy, with highs around 70 degrees. Lows on Friday night will only drop into the 60s. Some slight rain chances return Friday night.
Saturday and Sunday
An approaching frontal system from the west is going to bring wetter conditions this weekend. Generally, I think we can expect highs in the mid-70s on Saturday, with fairly widespread, light to moderate showers. It won’t be wall-to-wall rain, but beginning Saturday morning we’ll see healthy rain chances that persist through the weekend. At some point a front is likely to move into the area, and this likely will occur on Saturday night or Sunday morning, some time. Sunday, therefore, will probably be cooler, in the 60s, with ongoing 60 to 70 percent rain chances. At this time the weather pattern appears unlikely to support severe thunderstorms, but we shall see.
Next week
I expect rain chances to linger after this front, probably through Monday and into Tuesday, even as we see gradually falling temperatures. We should see a few colder days next week, with highs perhaps only in the 50s, and lows in the upper 30s or 40s. I don’t think a freeze is in the cards, but Houston is definitely going to feel a lot more like winter. We’ll keep a close eye on the forecast to see how it develops, and alert you if a freeze is likely.
Fundraiser
We’re into the final week of our annual fundraiser. Your support this year has been tremendous, and we really appreciate any help you can give. More information on how to donate or purchase merchandise can be found here.
