Texas Winter 2013-2014

[srainhoutx]

What needs to happen for this cold air to move more Eastward? Someone mentioned the southeast ridge and the -PNA Does the ridge need to weaken? Shift Eastward? Is this something that looks to be locked in for a long time? I hope this isn't what I can expect all winter, just missing out...

Typically we really cannot predict with any certainty just how far E or even if there will be moisture available beyond the 24-48 hour range. This is one of the reasons that the HPC/WPC Winter Weather Outlooks do not extend beyond 72 hours. As we saw with the last event, even with sounding data that supported a warm nose aloft, sleet fell for a period in the N Texas area shortly after the Arctic front was well to the S and even within a few hours of a special sounding in College Station last Tuesday, we experience snow/sleet mixed with rain as the upper low passed overhead. For you folks in SE Louisiana, what we will be watching for is a possible Coastal Low/trough to develop and just where it does develop and track if it does at all. That said the embedded short wave (upper air features/disturbance) riding S along the Western side of the Great Basin into the base of the trough suggests that even folks a bit further E may have to deal with wintery mischief. We will see.

[richtrav]

I dont think this cold is anything like '83 or '89. As of now it doesnt even come close, but this air is modified big time by the pacific and its STILL this cold. It def had the potential to be epic but its not. I dont know of what we could compare it too. Maybe Dec 1990 since it affects the West coast so much.

Dec 1990 is the first thing I thought when this system started hinting at forming several days back, when they had Seattle dropping to near-zero. Those bitterly low temps aren't going to play out but the generally western pattern is still there. But it looks like it could be a 1990 lite, which was a monster freeze out west, TX got sideswiped but for CA, WA, NV etc it was epic. Right now it has Las Vegas stuck in the 30s for highs for several days.

In 1990 DFW spent about 48 consecutive hours in the teens with over 24 of that in the mid-teens, and a min about 10F when the sky cleared the last night. Don't expect anything that severe but the GFS does seem to be locking DFW into a long period in the 20s. I'd be very surprised if this turned out as severe as Feb 2011 since the system isn't as strong and given the time of year.

For us in S TX it looks like we're in for a sucky cold weekend similar to the period right before Thanksgiving, fortunately followed by a healthy warmup (if you take the long-range GFS at face value).

[orangeblood]

Euro staying fairly consistent with snowfall over the next 10 days.....

[CYCLONE MIKE]

Try this site BigB

http://wxweb.meteostar.com/sample/sample.shtml?text=KBTR

Shows Lafayette stuck in the low 40s and eventually upper 30s with precipitation for about 3 days. Still a long ways out and temps can change up or down but it looks like some places in Louisiana may see a significant winter storm. Hopefully we all get a taste!

Sounds just like last week. God that was miserable. Dropped our water temps along the gulf coast where I fish from low 60's to upper 40's in less than a week. Fish had lockjaw and in shock this weekend.

[srainhoutx]

Sunday afternoon Update from Jeff:

Warm up in progress over the region today as the retreating arctic dome from last week is replaced with increasing warm air advection.

Very cold air mass is building over NW Canada poised to move southward this week.

After a cold end to the month of November, the first week of December will be mild with continuous warm air advection pumping moisture and a Gulf air mass into the region. Surface dewpoints will gradually increase each day through the week reaching the 60’s and possibly approaching 70 by the middle to end of the week. Recent cold air event over the NW Gulf has cooled nearshore water temperatures into the upper 50’s and low 60’s, so dewpoints rising above those levels could result in dense sea fog formation at some point by the middle of the week. Surface temperatures will warm well into the 70’s this week with lows rising into the upper 50’s and eventually the 60’s by Thursday. Rain chances begin to increase on Wednesday and Thursday as moisture deepens.

While we warm, bitter cold air mass will invade the NW US into much of the northern Rockies this week under the influence of a sprawling arctic high pressure dome. Impressive pressure differences are noted along the front range of Colorado by the middle of the week with some suggestion of 30+mb from NW to SE Colorado suggesting a very strong arctic boundary. Temperatures behind this boundary will be very cold for early December with anomalies running upwards of 20-30 degrees below normal for this time of year….this is some impressive cold air for this time of year.

There is little doubt that this cold is coming southward as is so often the case with shallow dense cold arctic air masses. Will see a powerful arctic boundary arrive into the state Thursday and plow off the coast on Friday. Temperatures ahead of the boundary will likely approach 80 on Thursday and Friday (depending on frontal timing) and then tumble behind the front. Rain and showers will accompany the frontal passage and linger in the post frontal cold air. Will easily see temperatures fall a solid 20 degrees with the front and 24-hr temperature differences between Friday and Saturday could be 30-40 degrees. Good potential for much of the area to fall into the 30’s Friday night and stay below 40 into the second week of December for both highs and lows. To complicate matters more, models have been fairly consistent in overrunning the shallow cold dome with plenty of moisture through the weekend resulting in cloudy conditions with periods of drizzle and light rain. Will have to address P-type issues at some point in the next few days as this air mass is colder than the one last week which would support freezing precipitation if surface temperatures are 32 degrees or colder. GFS model continues to hint at shallow surface sub-freezing layer with periods of light rain suggesting freezing rain is possible. Everyone should understand that we are talking 5-6 days out and the chances that the models are correct with the surface air temperature within 1-2 degrees is very unlikely which could make all the difference between ice and a very cold rain. Much uncertainty for next weekend into the second week of December with just how cold the area will get, for how long, and if there will be any winter precipitation.

[Ntxw]

Euro staying fairly consistent with snowfall over the next 10 days.....

Personally, I do believe the models are underplaying the shortwave riding the Arctic front. The tropical connection from the westerlies is strong and are highly underestimating vorticity digging in from the PAC NW. We saw a similar system before the blitz in 2011, models too focused on the northern stream. The big block will bundle energy at the base of the trough and the storm coming out on the front will likely be a sub 1000mb system with a tight pressure gradient and very strong baroclinic zone extending from west Texas to Arkansas. The same bias of trying to push warmer air back due to SW flow is at play yet again, one that I think will lose.

For now I think areas that should watch for icing would be central and southeast Texas, further north most guidance is fairly stable with 540 thickness extending further south than the last air mass, meaning deeper cold air north of I-20.

[Portastorm]

For those suggesting the pattern ahead reminds them or resembles December 1990, I went back and looked at the synoptics for that period. There definitely are *some* similarities between what the Christmas-time pattern in 1990 showed and what the models are showing for next weekend. But there are some important differences as well. In 1990, a full latitude trough was progressive in nature and moved across the western and central/southern US bringing with it very cold and smaller amounts of precip. Next weekend's period also show's a full latitude trough somewhat progressive in nature but not as much as what happened in 1990. Point being is there probably won't be much of a warm-up after next weekend's event and we'll probably see more cold outbreaks following.

By the way, if you're wondering how to play Back to the Future in the weather world ... here's one link where you can look into the past:

http://www.meteo.psu.edu/~fxg1/NARR/index.html

[TeamPlayersBlue]

I think my pipes busted that year in Houston. My mother and i went to Colorado for my first ski trip and we didnt even get to winter park due to the cold and snow. It was stupid cold in Denver. My mom said something like 20 below.

[wxman57]

I think my pipes busted that year in Houston. My mother and i went to Colorado for my first ski trip and we didnt even get to winter park due to the cold and snow. It was stupid cold in Denver. My mom said something like 20 below.

The big freeze here was 1989, not 1990.

[TeamPlayersBlue]

I think my pipes busted that year in Houston. My mother and i went to Colorado for my first ski trip and we didnt even get to winter park due to the cold and snow. It was stupid cold in Denver. My mom said something like 20 below.

The big freeze here was 1989, not 1990.

Yeah i remember that one, i was here and our pipes didnt freeze. It was either 1990, or 1991, but i thought it was '90.

1989 is in a class of its own

[dhweather]

Wow, the 12Z GFS has Love Field below freezing from Friday - Wednesday. Lows Monday/Tuesday around 15.


As always, if it's gonna be THAT cold, it BETTER snow!



And as always, model errors can be large this far out, so stay tuned.

[Wntrwthrguy]

This may have been explained before but how do you get below freezing temps across all layers of the atmosphere compared to the shallow layer of cold air that is predicted to come down this weekend? Is it the origin of the air that causes the cold air to be shallow or deep?

[Rgv20]

Joe Bastardi thinks the Brownsville area might be in for a freeze! My area already had its first light freeze earlier this week...got down to 32F.

Joe Bastardi @BigJoeBastardi
LRGV of Texas should see temps 28-32 with this surge this weekend or early next week
5:09 PM - 1 Dec 2013

[orangeblood]

This may have been explained before but how do you get below freezing temps across all layers of the atmosphere compared to the shallow layer of cold air that is predicted to come down this weekend? Is it the origin of the air that causes the cold air to be shallow or deep?

Below is a side view of how the air masses might interact later this week. The polar air mass, being much denser than the warm air mass in front of it, hugs the surface and and creates a wedge of sort as it moves south. It becomes much deeper as you get closer to the Core of the Cold High Pressure. Thus precip type can vary rather quickly across a short distance. Many times the computer models under estimate the density of the arctic cold and have a hard time pin pointing the southern extent of the boundary.

[Ntxw]

And to add, generally you can tell if it's shallow or not by looking at 5h. If Surface temps are below freezing while you see 564+ heights generally that is a dense shallow air mass. 558 or lower typically shows you are in deeper cold air. That's usually associated with lower pressure (storms). It's not perfect but a good rule to go by. The closer you are to the 540 (not at 5h but composite) thickness line the more likely it is snow vs the other frozen nightmares.

[Ntxw]

CPC sees the cold assault on middle America

[Portastorm]

This may have been explained before but how do you get below freezing temps across all layers of the atmosphere compared to the shallow layer of cold air that is predicted to come down this weekend? Is it the origin of the air that causes the cold air to be shallow or deep?

There are a LOT of variables involved so, unfortunately, there's not an easy answer to your question. You may have the lower level flow dictated from the north with mid levels dominated by flow off the Gulf of Mexico or the Pacific (i.e. from the southwest). In those circumstances you'll have a layer or two of air just above the surface with temperatures above freezing due to the origin of the air. Sometimes an upper level low will move west to east across the state and those are generally very cold from bottom to top so if you end up underneath one (or close to one), the odds of frozen precip as compared to freezing rain may significantly rise.

Here's a nice little page which explains some of it, I think:

http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/cld/prcp/zr/fcst/fcst.rxml

[Wntrwthrguy]

Thanks for all of the models and explanations. It's what makes weather so fascinating to me with all of the different variables that are involved. It sounds like it's way too early to tell if it will be a freezing rain/sleet/snow event for the austin area this weekend but I'll be keeping up with everything here. I'm moving on Friday morning so I'm hoping whatever does come precip wise will wait until Friday night.

[wxman57]

18Z GFS Houston meteogram isn't any warmer. Very cold rain, possibly a bit of freezing rain and sleet. Just about the worst possible weather.

[jerryh421]

GFS continues to show a possible freezing rain and sleet just north of Houston.