Texas Winter 2019-2020

[wxman57]

Looked at the 18Z GFS ice forecast for Texas next week then checked the upper air pattern valid at the same time. It's not what I expected, at all. The surface pattern and icy mix doesn't seem to match the upper-air pattern. Typically, when that happens, the surface map is going to be changing. I'm not buying the big ice storm solution yet.

By sheer weight of the dense, cold air near the surface. Whatever comes out of Western Canada should be quite cold. Of course the upper air pattern would say to hold it up. Something also comes out of the subtropical jet stream.

What happens with the Pacific ridge can have big changes. A progressive ridge will likely push the cold air down. That's quite cold though in the northern tier! If I were you, I'd be maybe unnerved it might test your wall.

https://i.imgur.com/sf6YwWs.png

The air looks colder than what it was in November.

I know about the challenges with shallow, dense, Arctic air. This is my 41st year forecasting in Houston. The upper-air pattern is quite irrelevant as far as any southward movement of Arctic air. It sinks south through Texas no matter what the upper-level winds are doing. What I'm not seeing, though, is a pattern that would produce any significant precip in any cold air. The EC is still bringing the front through, but with not much precip behind it. I do notice that the EC doesn't bring as much cold air down as the GFS, and the EC may be making the mistake of moving the cold air out too quickly, which is often a problem with how models handle Arctic air.

One thing about these fronts is that we really won't have a good idea just how much cold air will move south until it is already on the move to the south, maybe only 48 hours before it reaches Texas. You can't trust the long-range models (beyond 72 hrs) to handle the forecast well. Let's see what moves south into Montana next week and then see if we can identify any post-frontal disturbances that might produce widespread precip. I think that the EC may move toward more cold air and the GFS toward less frozen precip over the coming week. We'll see.

[Cpv17]

Man, the 6z GFS says hello to the Abilene area. My goodness lol

[bubba hotep]

06z Euro for DFW

[ThunderSleetDreams]

Later on past next week...

[harp]

Question: Any chance some of this stuff could bleed over to south Louisiana?

[Portastorm]

Looked at the 18Z GFS ice forecast for Texas next week then checked the upper air pattern valid at the same time. It's not what I expected, at all. The surface pattern and icy mix doesn't seem to match the upper-air pattern. Typically, when that happens, the surface map is going to be changing. I'm not buying the big ice storm solution yet.

By sheer weight of the dense, cold air near the surface. Whatever comes out of Western Canada should be quite cold. Of course the upper air pattern would say to hold it up. Something also comes out of the subtropical jet stream.

What happens with the Pacific ridge can have big changes. A progressive ridge will likely push the cold air down. That's quite cold though in the northern tier! If I were you, I'd be maybe unnerved it might test your wall.

https://i.imgur.com/sf6YwWs.png

The air looks colder than what it was in November.

I know about the challenges with shallow, dense, Arctic air. This is my 41st year forecasting in Houston. The upper-air pattern is quite irrelevant as far as any southward movement of Arctic air. It sinks south through Texas no matter what the upper-level winds are doing. What I'm not seeing, though, is a pattern that would produce any significant precip in any cold air. The EC is still bringing the front through, but with not much precip behind it. I do notice that the EC doesn't bring as much cold air down as the GFS, and the EC may be making the mistake of moving the cold air out too quickly, which is often a problem with how models handle Arctic air.

One thing about these fronts is that we really won't have a good idea just how much cold air will move south until it is already on the move to the south, maybe only 48 hours before it reaches Texas. You can't trust the long-range models (beyond 72 hrs) to handle the forecast well. Let's see what moves south into Montana next week and then see if we can identify any post-frontal disturbances that might produce widespread precip. I think that the EC may move toward more cold air and the GFS toward less frozen precip over the coming week. We'll see.

Gang, we love to tease him and he loves ribbing us back ... but I have known Wxman57 a long time and what he says above is spot on. If and when there is a legitimate winter storm/Arctic outbreak threat to Texas, he will be all over it and faithfully share his professional insights. Many of you who are highly educated enthusiasts know that what he is saying above is accurate. At this point we can believe that some kind of pattern change will arrive in the next two weeks. The details may not be worked out until a few days before as our esteemed cycling-loving, heat-worshipping meteorologist tells us.

[Cerlin]

By sheer weight of the dense, cold air near the surface. Whatever comes out of Western Canada should be quite cold. Of course the upper air pattern would say to hold it up. Something also comes out of the subtropical jet stream.

What happens with the Pacific ridge can have big changes. A progressive ridge will likely push the cold air down. That's quite cold though in the northern tier! If I were you, I'd be maybe unnerved it might test your wall.

https://i.imgur.com/sf6YwWs.png

The air looks colder than what it was in November.

I know about the challenges with shallow, dense, Arctic air. This is my 41st year forecasting in Houston. The upper-air pattern is quite irrelevant as far as any southward movement of Arctic air. It sinks south through Texas no matter what the upper-level winds are doing. What I'm not seeing, though, is a pattern that would produce any significant precip in any cold air. The EC is still bringing the front through, but with not much precip behind it. I do notice that the EC doesn't bring as much cold air down as the GFS, and the EC may be making the mistake of moving the cold air out too quickly, which is often a problem with how models handle Arctic air.

One thing about these fronts is that we really won't have a good idea just how much cold air will move south until it is already on the move to the south, maybe only 48 hours before it reaches Texas. You can't trust the long-range models (beyond 72 hrs) to handle the forecast well. Let's see what moves south into Montana next week and then see if we can identify any post-frontal disturbances that might produce widespread precip. I think that the EC may move toward more cold air and the GFS toward less frozen precip over the coming week. We'll see.

Gang, we love to tease him and he loves ribbing us back ... but I have known Wxman57 a long time and what he says above is spot on. If and when there is a legitimate winter storm/Arctic outbreak threat to Texas, he will be all over it and faithfully share his professional insights. Many of you who are highly educated enthusiasts know that we he is saying above is accurate. At this point we can believe that some kind of pattern change will arrive in the next two weeks. The details may not be worked out until a few days before as our esteemed cycling-loving, heat-worshipping meteorologist tells us.

There’s not a single person I trust more than him with this stuff. Every time DFW has a potential close call, he’s usually the dissenter, but usually correct.

[ThunderSleetDreams]

I went back and read about the 1/16/18 Winter Storm in the Southern half of Texas up through the Piney Woods.

If you start at Page 310 and roll through the 330s, you can see the joy in everyone's typing fingers. Here's to another one, except this time, lets throw a quarter inch of freezing rain, followed by a couple inches of sleet, topped off with 4 inches of snow! In the midst of all of that, I'd like some Thunder Sleet during the changeover.

[EnnisTx]

Models not only show the potential threat on the 17th and 18th but again on the 21rst through 23rd. It will be interesting to see how this all pans out.

[ThunderSleetDreams]

Models not only show the potential threat on the 17th and 18th but again on the 21rst through 23rd. It will be interesting to see how this all pans out.

The 21st through 23rd have a much more favorable upper air pattern. Deep dig into the SW and ejection right across Texas. During that time frame, it looks like some gnarly ice accumulations for DFW as they would be right in the battleground.

[lsuhurricane]

12z GFS looking bleak for southern plains as primary cold source is shunted east. We've seen this movie one too many times....

[mcheer23]

Well the 12z was a massive flip

[Tireman4]

By sheer weight of the dense, cold air near the surface. Whatever comes out of Western Canada should be quite cold. Of course the upper air pattern would say to hold it up. Something also comes out of the subtropical jet stream.

What happens with the Pacific ridge can have big changes. A progressive ridge will likely push the cold air down. That's quite cold though in the northern tier! If I were you, I'd be maybe unnerved it might test your wall.

https://i.imgur.com/sf6YwWs.png

The air looks colder than what it was in November.

I know about the challenges with shallow, dense, Arctic air. This is my 41st year forecasting in Houston. The upper-air pattern is quite irrelevant as far as any southward movement of Arctic air. It sinks south through Texas no matter what the upper-level winds are doing. What I'm not seeing, though, is a pattern that would produce any significant precip in any cold air. The EC is still bringing the front through, but with not much precip behind it. I do notice that the EC doesn't bring as much cold air down as the GFS, and the EC may be making the mistake of moving the cold air out too quickly, which is often a problem with how models handle Arctic air.

One thing about these fronts is that we really won't have a good idea just how much cold air will move south until it is already on the move to the south, maybe only 48 hours before it reaches Texas. You can't trust the long-range models (beyond 72 hrs) to handle the forecast well. Let's see what moves south into Montana next week and then see if we can identify any post-frontal disturbances that might produce widespread precip. I think that the EC may move toward more cold air and the GFS toward less frozen precip over the coming week. We'll see.

Gang, we love to tease him and he loves ribbing us back ... but I have known Wxman57 a long time and what he says above is spot on. If and when there is a legitimate winter storm/Arctic outbreak threat to Texas, he will be all over it and faithfully share his professional insights. Many of you who are highly educated enthusiasts know that what he is saying above is accurate. At this point we can believe that some kind of pattern change will arrive in the next two weeks. The details may not be worked out until a few days before as our esteemed cycling-loving, heat-worshipping meteorologist tells us.

Agreed Porta. We have known him a LONG LONG time ( and yes, he has really dished out on his..LOL) and I trust him implicitly. His rule of thumb is, "the trend is your friend, if the factors are there 5 days out, it is enough to raise an eyebrow"...( this is for the newbies...LOL)

[Cerlin]

Remember everyone—its just one run and it’s far out still. Look for the trends, not the outlier.

[ThunderSleetDreams]

Well the 12z was a massive flip

The upper air pattern on the 12z makes even less sense when compared to its surface map.

[wxman57]

I sent NCEP revised data on my wall along the Canadian border overnight. The data was incorporated into the 12Z GFS run, apparently.

Do I believe the latest GFS run, which closely matches the 00Z Euro? Nope, even though I'd love to miss out on Arctic air and very cold rain. I'm not going to trust any of the models until maybe next Monday or Tuesday, when the event is 48-72 hrs out.

Looking at the 12Z GFS 500 mb pattern, it still doesn't match the GFS surface. It's hardly suggestive of any cold front of significance, nor any significant precip next Wed-Fri. It just looks wrong. Oh well, maybe we'll get a little rain Friday night to water the plants. Nothing significant since Nov. 7th here in SW Houston.

[vbhoutex]

From Jeff Lindner

Severe thunderstorms will be possible over portions of SE TX Friday evening into early Saturday morning.

All severe weather modes will be possible.

A powerful upper level storm system will dig into the SW US and then sweep across TX Friday and Friday night. Ahead of this system a robust and highly sheared warm sector air mass will develop Thursday into Friday. Air mass will undergo rapid modification from the current dry and cold to warm and moist by late Friday. As the upper level trough begins to move toward TX late this week, a surface cold front and associated surface low pressure system will develop over the southern plains. Moisture transport on a powerful low level jet by Friday morning is impressive over SET X with 40-60kts at 850mb and PWS rising into the 1.5 inch range. High temperatures warming into the mid to maybe upper 70’s along with the influx of a “Gulf” air mass will support modest instability for this time of year with CAPE values of 1000-1500J/kg across the region by late afternoon. It should be noted that “cool” season severe weather outbreaks along the Gulf coast tend to not need as much instability as similar systems in the Spring and significant severe weather and tornadoes have occurred with similar setups in the past (especially over LA, MS, AL). Elevated mixed layer (cap) will advect ENE across SE TX from northern MX during the day Friday and this should prevent much activity across the developing warm sector for much of the morning into the early afternoon hours. Warm sector air mass will become highly sheared by Friday afternoon with a strong low level jet in place over SE TX with winds turning with height into the 700mb and 500mb levels.

Main question for Friday afternoon is does the cap waken enough to allow discrete cells to develop across the warm sector…and this potential looks possible along and north of I-10 and more likely north of HWY 105. Any discrete cells that can develop and break the capping inversion Friday afternoon will have plenty of low level wind shear in place for damaging winds and tornadoes. Strong surface winds of 25-35mph will be in place across the region Friday afternoon and evening with the strong low level jet overhead…and some of this stronger wind energy will mix down in any showers or storms that form.

Cap looks to erode fairly quickly Friday evening as strong linear forcing approaches from the WNW along an advancing cold front. Squall line is likely to develop and sweep across much of the region. Main threat will likely be the potential for wind damage as strong winds aloft may be transported to the surface in the line. Additionally bowing segments along the line could produce wind damage and isolated tornadoes. All severe modes will be possible, but wind damage is looking the most likely with the profiles in place.

SPC has outlooked most areas north of I-10 for an enhanced risk of severe weather for late Friday.

Storm system will be progressive and will quickly sweep across the region. Rainfall amounts look to average 1-2 inches with the greatest amounts toward Lake Livingston and lesser amounts toward Matagorda Bay.

Next Week:

Unsettle weather pattern will remain in place with a weak system moving across the area early in the week with more showers and maybe a thunderstorm. Of more interest is the potential for a very cold air mass to move into the northern plains early next week. This cold air mass has been lurking in western Canada since around Christmas and appears to dislodge some early next week. Models are showing -30’s over eastern Montana and North Dakota by next Tuesday and Wednesday. While the upper level pattern is not overly favorable for the delivery of this cold air mass southward, will need to watch for the air mass to “bleed” southward under its heavy density (such cold air is very heavy and spread across the surface like water on a table) and possibly reach TX by late next week in the form of a shallow, but very cold arctic front.

[South Texas Storms]

The cold air and winter storm threat is just a little delayed on the 12z GFS. It's still there...just a few days later in January

[stormlover2013]

guys its over a week out, please don't believe the models and trust them lol!! yall are better than this.

[ThunderSleetDreams]

The cold air and winter storm threat is just a little delayed on the 12z GFS. It's still there...just a few days later in January

Yep, and as I’ve been staring, the upper air pattern the week of the 20th would deliver the goods to us.