Whilst doing the forecast yesterday, I was pulled away halfway through. My “9-to-5” weather job needed me to produce some data quickly So I did. Then when I came back to our forecast I realized that my brain did not catch up.
Something happened – for the first time! – that I feared would happen since the day I left TV and took a weather job elsewhere: I confused the dates of two forecasts.
So let me clear things up: Friday morning is when we will see a potential for troublesome weather (rain and maybe some patchy freezing rain and sleet) not Thursday.
If you’re curious what will happen Thursday that had my brain all discombobulated: South Korea will be cold. Very cold. Temperatures will be in the teens!
But for us.. Friday is the day. Friday! Friday! Friday!
Okay! Not that I have that drilled into my head. Let’s look at the forecast….
SOME NOTES
I want to walk through some details that I may not ahve touched on thoroughly enough yesterday.
IT’LL BE COLD
That hasn’t changed. We are still looking at chilly weather to stick around through Thursday and then the next system arrives on Friday with a shot for precip. Lows will continue to tumble overnight into the mid to upper 20s with afternoon highs only scraping out the mid 40s for most. Some folks may struggle to even get past 40 degrees.
And I can assure you that in the shade, it will feel mighty chilly.
THERE WILL BE PRECIP
Starting Friday morning we will see the next system arrive and push a batch of moisture into the area. And, in fact, for some folks this could start as early as late Thursday night. But anything that falls before midnight would be very, very light, given the latest available model data.
The precip will plow through the cold air in place and offer some folks a chance at some wintry precip. This will be mainly north of I-20 and all the way up to I-40. Folks south of I-20 to about HWY 84 may see a brief round of freezing rain adn sleet as things begin, but based on the data should switch over to just regular rain pretty quickly.
Then south of HWY 84 to HWY 98, a very few spots may see some sleet pellets mix in, but otherwise, it’ll be all liquid.
South of that, a cold rain.
SNOW ISN’T LIKELY
Unlike out typical setup where as the next system through after a cold shot like this warms us up a ton, this one will not. Instead, it will glide by to the south, out into the Gulf perhaps. This means our wind will not shift fully around to the south. It will remain a bit easterly, leaving the cooler air to stay in place at the surface.
But that is only at the surface. Aloft, we will flip the wind back to the south. That means warmer air will likely be in place above us to melt any potential snowflakes.
This map from NOAA shows the path the air will take to get here in the 72 hours prior to Friday morning. And it is outlined at each different altitude. Our surface air, in red, will be from the Dakotas, the air up around 3,500ft will be from New Mexico but will dive brief out over the Gulf before coming back north, and our air up around 9,000ft will be from the northern Bay of Campeche in the Gulf of Mexico.
And then, when you look at the Skew-T data. This is where the follow the red line,, at a bit of an angle, from teh bottom of the chart to the top of the chart to track which side of the freezing line it is one, and when. We can see where temperatures will be above freezing — from about 10,000ft all the way to the surface (it is on the right side of the dotted blue line).
With temperatures at the surface around 35F. it will be cold enough to snow, but it will be falling as rain.
Mostly.
I will say that sleet may mix in for some folks briefly here and there through about 9am on Friday morning given that there will be the thinnest of slices of the atmosphere that will be dry enough that the process of evaporation and sublimation within that zone may allow it to cool down below freezing. That would allow for small sleet pellets to form.
That said, either way, it’ll be above freezing at the surface.
ONE LAST THING
Some of the model guidance is showing the temperatures to be really, really close to freezing throughout the column. Which means there is an outside shot – its not a great one – that this starts as all snow from about HWY 84 northward.
Or maybe even HWY 98 northward in some spots.
And, a bit like I’ve been saying we really need to wait until we are about 72 hours out before we can even start to get a reasonable idea about what the atmosphere will look like top to bottom.
And here we are.
And that Skew-T I showed suggests that the temperature from 10,000ft down to the surface will be between 32F and 38F. And if there is enough snow out the gate, it may start as snow.
But here is the bummer for you snow lovers, so far the model guidance shows that we should warm above freezing pretty quickly on Friday. So we would transition to rain.
Don’t worry, I have already heard the, “Yeah, well, remember what you said last time?” from some of you guys.
I know what some of you mean by “last time” too. You mean “Seven years ago.” But I get it. In fact, the forecasts from that event are still up on this website! You can read the forecast I produced on December 3rd here: https://www.nickelblock.com/gulf-coast-chill-offers-mainly-cold-drizzle-perhaps-wintry-precip/
But there is a big difference between this even and that event. This event shows a very moist atmosphere in the model guidance, that one showed some drier air closer to the surface (which allowed us to cool down through ‘wet-bulbing’ to a point where it could snow more) and the amount of precip in the guidance was pretty light, this is showing ‘a lotta watta’ with up to 2″ of rain possible for some folks.
For the record: If 2″ of rain fell as snow for us, it would be, like, a foot of snow. That is unlikely.
REGIONAL DAY TO DAY FORECAST
Today: Partly sunny. Highs in the mid 40s. North winds 10 to 15 mph.
Tonight: Partly cloudy. Cold with lows in the upper 20s. North winds around 5 mph.
Wednesday: Sunny. Highs in the upper 40s. North winds 5 to 10 mph.
Wednesday Night: Clear, cold with lows in the mid 20s. North winds around 5 mph.
Thursday: Increasing clouds. Highs in the mid 40s. Northeast winds 5 to 10 mph.
Thursday Night: Cloudy. A chance of rain showers in the evening, then rain showers likely after midnight. Not as cool with lows in the low 30s. Chance of rain 70 percent.
Friday: Rain showers. Highs in the mid 40s. Chance of rain 90 percent.
Friday Night: Cloudy. A chance of rain showers, mainly in the evening. Lows in the mid 30s. Chance of rain 50 percent.
Saturday: Mostly cloudy in the morning, then becoming mostly sunny. Highs in the upper 40s.
Saturday Night: Mostly clear. Cold with lows in the mid 20s.
Sunday: Sunny. Highs in the lower 50s.
Sunday Night: Mostly clear in the evening, then becoming partly cloudy. Cold with lows in the lower 30s.
Monday: Mostly sunny. A slight chance of rain showers in the afternoon. Highs in the mid 50s. Chance of rain 20 percent.
Thanks for all your efforts Nick. It’s appreciated, truly.