Texas Winter 2017-2018

[Cpv17]

06z NAM has came in a couple of degrees warmer. High pressure not quite as strong compared to 0z.

[Ralph's Weather]

Dang, now have to have an account for weather.us.

NAM shows moisture below 850mb on Sunday. Temps drop to around -5C at 900mb with surface near freezing Sunday at noon along I20 corridor of N and E TX. I could see that producing some flurries and maybe a dusting. Just not deep enough moisture for anything more than that.

[WeatherDuck]

Dang, now have to have an account for weather.us.

NAM shows moisture below 850mb on Sunday. Temps drop to around -5C at 900mb with surface near freezing Sunday at noon along I20 corridor of N and E TX. I could see that producing some flurries and maybe a dusting. Just not deep enough moisture for anything more than that.

How does it look for Central and Southeast Texas?

[Ralph's Weather]

Dang, now have to have an account for weather.us.

NAM shows moisture below 850mb on Sunday. Temps drop to around -5C at 900mb with surface near freezing Sunday at noon along I20 corridor of N and E TX. I could see that producing some flurries and maybe a dusting. Just not deep enough moisture for anything more than that.

How does it look for Central and Southeast Texas?

NAM shows the timing of flurries to be Sunday night though moisture by then is even less than in N TX earlier I the day.

[AubreyStorm]

Weather Alert
Special Weather Statement issued December 29 at 5:51AM CST by NWS Dallas-Fort Worth

...Freezing Precipitation and Minor Ice Accumulations Possible... * LOCATIONS IMPACTED...All of North and Central Texas have a potential of minor ice accumulation with the greatest risk occurring along and northwest of a Comanche to Cleburne to Dallas to Sulphur Springs line. * TIMING....Beginning as early as Saturday afternoon north of a Graham to Gainesville line. The threat for freezing precipitation will slowly advance southeastward and reach a Comanche to DFW to Sulphur Springs line by sunrise Sunday morning...and to a Killeen to Waco to Athens line by early afternoon. All of North and Central Texas will be below freezing by late Sunday afternoon. All wintry precipitation will end from north to south starting Sunday afternoon through Sunday evening. * ACCUMULATIONS...Light icing of a trace to less than 1/10 of an inch possible. * IMPACTS...Minor icing on elevated surfaces, such as bridges, overpasses and some surface streets may lead to hazardous travel. * COLD TEMPERATURES...Wind chills Sunday evening will drop into the teens across the entire area. By Monday morning single digit wind chills are likely. Prepare for the possibility of hazardous travel in parts of North and Central Texas Saturday night through Sunday evening. If possible, consider amending plans to avoid traveling during this timeframe.

[srainhoutx]

For planning purposes particularly gardeners and those that need to protect exposed water pipes and irrigation systems along and North of I-10, HGX is stating they will likely issue a Hard Freeze Warning New Years Day for Tuesday through Wednesday mornings and Wind Chill Advisories/Warning may also be needed. Current low temperatures in those areas are expected to drop to the low/mid 20's with some Upper Teens possible in the coldest areas. They are also stating that a freeze is likely to the Beaches along SE Texas.

[Yukon Cornelius]

For the last few days we've had a temp bust towards being quite a bit colder than forecasted. Last night was the first temp bust toward warmer than forecasted in quite some time.

[CaptinCrunch]

.LONG TERM... /Issued 409 AM CST Fri Dec 29 2017/
/Saturday through Thursday/

We are now in range of some of the higher resolution models which
typically handle shallow cold airmasses better and also utilize
cloud parameterization schemes that are able to forecast light
precipitation events like drizzle. As a result some notable
changes to the winter precip forecast were made (particularly
with the timing of the event) to align with this suite of model
guidance.

On Saturday morning a shortwave will cross the region in northwest
flow aloft and open the flood gates for the arctic airmass
situated across the plains to pour into the region. This process
will be orderly Saturday with winds gradually becoming north and
increasing to near 10 mph, surface pressures rising, and
temperatures either steady or falling during the day. Moisture
just above the surface will result in low clouds and some drizzle
as the cold advection maintains saturation and squeezes out the
excess moisture as temperatures progressively cool. This typically
is an indication of drizzle, because the cloud depth is too
shallow to produce larger raindrops. The chance of seeing
measurable rainfall from this activity is on the low-side so PoPs
will only be between 20 and 30 percent, however most locations
should see a trace of precip...or enough to wet the ground.

Temperatures are expected to fall below freezing now over the
northwestern zones as early as Saturday afternoon with the freeze
line progressing southeastward during the night. By daybreak we
are forecasting the freeze line to reach a Comanche to DFW to
Sulphur Springs line. Obviously this means that any locations
north of this line will have to contend with the drizzle freezing
on contact with the surface. Freezing drizzle is usually very
effective at sticking to the surface, often because the cloud
droplets are supercooled below freezing. While freezing drizzle
events don`t result in heavy ice accretion that brings down trees
or powerlines, they do cause traffic issues - especially on
elevated roads and bridges. During the day Sunday the freeze line
will continue to march southeastward with temperatures continuing
to fall over the entire CWA. The freeze line should reach the
Waco area around noon and finally clear the southeastern zones
before sunset.

The other big story will be the cold temperatures. By midnight New
Year`s Eve temperatures will be in the 20s areawide with wind
chills in the single digits to teens. Temperatures will continue
to fall through the night with lows Monday morning ranging from 13
in the NW zones to 25 in the far SE. Clouds should clear most of
the region during the overnight hours, but radiational cooling
will be limited by the 15 mph northerly winds. For New Year`s Day
generally sunny skies are expected with highs in the mid 20s over
the NW to mid 30s in the southeast. Winds still don`t relax enough
to allow for good radiational cooling Monday night and there are
some indications of increasing low-mid clouds moving in from the
southwest by Tuesday morning as a weak disturbance moves through.
This should keep lows on Tuesday morning from falling beyond the
teens to low 20s. Highs on Tuesday will be in the low to mid 30s,
but if more clouds are present with the disturbance these may end
up being a little lower. Clearing should occur Tuesday night and
the center of the surface high will track across the region.
Temperatures may bottom out near 10 in a few of the traditionally
colder locations, but teens to low 20s are expected to be the
rule.

Another reinforcing cold front will move through Wednesday which
will serve to keep highs generally in the 30s and lows in the 20s
into the later part of the week. No precipitation is expected with
dry northwesterly flow aloft prevailing. The reservoir of arctic
air will be exhausted by next weekend and in classic Texas
fashion we`ll probably be looking at highs near 70 by Jan 7th as
the upper pattern switches to a more zonal flow.

[wxman57]

Overnight runs of the GFS and Euro are pretty close together now. Cold in SE TX but no precip. Upper 20s in the Houston area and low 20s up in the DFW area on a few days next week. Highs only in the 30s. Colder than normal but no really big deal. Canadian is still nuts temperature and precip-wise. Could see a few snow flurries up north (DFW) as the precip ends Sunday, but that may be it. One issue as far as extreme cold is that the snow pack is just not very far south for this time of year. The air is modifying more as it moves south.

[Ntxw]

Looking at the short range guidance (NAM and RGEM) they pretty much agree on height rises for DFW around 6-9pm tomorrow night and close to freezing by midnight if not a few hours sooner. GFS diverges and is still 10 degrees warmer than both. Above freezing Sunday and falls to freezing by midnight Sun-Mon. While the RGEM and NAM are already well into the 20s on Sunday for highs.

I'm going out on a limb and say the GFS is out to lunch with frontal passage.

Also NAM still has snow flurries/snow showers for the I-20 corridor and north to the Red River as the front comes through.

[Ntxw]

GFSX (MOS output) has 18, 14, 18 for lows Mon-Tues-Weds at DFW. Again will be interesting to see if the NWS favor the MOS data as that is their love child for day to day forecasting

[CaptinCrunch]

I agree with Ntwx, the surface temp will be colder than modeled, and the freeze line through DFW early evening on Saturday. Either way NTX will sit below the freezing mark for almost 72hrs.
[img]

[Ntxw]

A look up in the Great White North (Canada)





The -EPO has really delivered in making it cold in Canada. DFW (and many in Texas) have not had a duration of cold like this since 2013-2014

[CaptinCrunch]

With 6 straight days of below average daily temps the December monthly mean has dropped to +3.6 which isn't bad considering how the month started off. These next 3 days should continue the below avg streak and December could end with a decent +1.9 which is pretty much average for NTX.

[Ntxw]

With 6 straight days of below average daily temps the December monthly mean has dropped to +3.6 which isn't bad considering how the month started off. These next 3 days should continue the below avg streak and December could end with a decent +1.9 which is pretty much average for NTX.

After Dec 21stish it's been predominantly below average. You are right the start of the month really skyrocketed the average. To bring it down from that ceiling took some persistent cold and it's happened! If you take the averages from the official start of winter (21st) and roll it forward it's really cold. When done by Jan 15th it will be interesting to see how much it averages from that point.

[CaptinCrunch]

With 6 straight days of below average daily temps the December monthly mean has dropped to +3.6 which isn't bad considering how the month started off. These next 3 days should continue the below avg streak and December could end with a decent +1.9 which is pretty much average for NTX.

After Dec 21stish it's been predominantly below average. You are right the start of the month really skyrocketed the average. To bring it down from that ceiling took some persistent cold and it's happened! If you take the averages from the official start of winter (21st) and roll it forward it's really cold. When done by Jan 15th it will be interesting to see how much it averages from that point.

Exactly, hard to remember the 21st was 78 degrees...lol. We averaged 16 degrees above normal the first 4 days of December, then 12.5 above the 19th-21st. It's been a nice recovery.

[Ntxw]

Also South Texas Storms posted about this some pages back. The ULL disturbance will come through Texas Monday night through Tuesday. No surface moisture to work with on guidance but as we often see if there is lift it will find moisture. With the air so cold you won't need much for it with even a little lift.

[TeamPlayersBlue]

We might need it to be further west for some action, but im staying positive!

[Ntxw]

Exactly, hard to remember the 21st was 78 degrees...lol. We averaged 16 degrees above normal the first 4 days of December, then 12.5 above the 19th-21st. It's been a nice recovery.

How about the GFS earlier in the week saying Sat-Sun was going to hit mid 50s this weekend before front? Yeah right, today is the best shot at 50.

[bubba hotep]

.LONG TERM... /Issued 409 AM CST Fri Dec 29 2017/
/Saturday through Thursday/

We are now in range of some of the higher resolution models which
typically handle shallow cold airmasses better and also utilize
cloud parameterization schemes that are able to forecast light
precipitation events like drizzle. As a result some notable
changes to the winter precip forecast were made (particularly
with the timing of the event) to align with this suite of model
guidance.

On Saturday morning a shortwave will cross the region in northwest
flow aloft and open the flood gates for the arctic airmass
situated across the plains to pour into the region. This process
will be orderly Saturday with winds gradually becoming north and
increasing to near 10 mph, surface pressures rising, and
temperatures either steady or falling during the day. Moisture
just above the surface will result in low clouds and some drizzle
as the cold advection maintains saturation and squeezes out the
excess moisture as temperatures progressively cool. This typically
is an indication of drizzle, because the cloud depth is too
shallow to produce larger raindrops. The chance of seeing
measurable rainfall from this activity is on the low-side so PoPs
will only be between 20 and 30 percent, however most locations
should see a trace of precip...or enough to wet the ground.

Temperatures are expected to fall below freezing now over the
northwestern zones as early as Saturday afternoon with the freeze
line progressing southeastward during the night. By daybreak we
are forecasting the freeze line to reach a Comanche to DFW to
Sulphur Springs line. Obviously this means that any locations
north of this line will have to contend with the drizzle freezing
on contact with the surface. Freezing drizzle is usually very
effective at sticking to the surface, often because the cloud
droplets are supercooled below freezing. While freezing drizzle
events don`t result in heavy ice accretion that brings down trees
or powerlines, they do cause traffic issues - especially on
elevated roads and bridges. During the day Sunday the freeze line
will continue to march southeastward with temperatures continuing
to fall over the entire CWA. The freeze line should reach the
Waco area around noon and finally clear the southeastern zones
before sunset.

The other big story will be the cold temperatures. By midnight New
Year`s Eve temperatures will be in the 20s areawide with wind
chills in the single digits to teens. Temperatures will continue
to fall through the night with lows Monday morning ranging from 13
in the NW zones to 25 in the far SE. Clouds should clear most of
the region during the overnight hours, but radiational cooling
will be limited by the 15 mph northerly winds. For New Year`s Day
generally sunny skies are expected with highs in the mid 20s over
the NW to mid 30s in the southeast. Winds still don`t relax enough
to allow for good radiational cooling Monday night and there are
some indications of increasing low-mid clouds moving in from the
southwest by Tuesday morning as a weak disturbance moves through.
This should keep lows on Tuesday morning from falling beyond the
teens to low 20s. Highs on Tuesday will be in the low to mid 30s,
but if more clouds are present with the disturbance these may end
up being a little lower. Clearing should occur Tuesday night and
the center of the surface high will track across the region.
Temperatures may bottom out near 10 in a few of the traditionally
colder locations, but teens to low 20s are expected to be the
rule.

Another reinforcing cold front will move through Wednesday which
will serve to keep highs generally in the 30s and lows in the 20s
into the later part of the week. No precipitation is expected with
dry northwesterly flow aloft prevailing. The reservoir of arctic
air will be exhausted by next weekend and in classic Texas
fashion we`ll probably be looking at highs near 70 by Jan 7th as
the upper pattern switches to a more zonal flow.

I don't doubt that the best of the arctic air will be gone by then but I don't see much to support a flip to a zonal torch. The MJO is forecast to be rolling through P3 by then and that should favor a mean SW trough. We could see a temp spike before any given storm system but that would be followed by a rapid cool down. Also, we are getting to the point in the winter that we don't need big cold anomalies to our north to get a winter storm in Texas. We just need seasonably cold air and the right timing. FWD Dallas office does great work and they will probably be right but we can hope they are wrong about a return to zonal flow.