December 2017: End Of The Year Weather

[mckinne63]

12z Euro is in and I don't see too many differences right off the bat. I do see it's pretty cold the day after Christmas but still only showing highs in the mid 40s the days before and on Christmas. Nothing that is Earth shattering. It keeps all precip liquid as well.

12z GFS is comparable to the Euro in showing highs in the mid Saturday, Sunday and Christmas Day. It does bring the rain/ice/snow line fairly close to College Station but that's about it. All rain here locally.

Model watching continues.

Cold is good! Ice not no much. I like it to be chilly for christmas! May actually fire up the gas logs in the fireplace.

[TexasMetBlake]

FWD AFD:

Medium range models continue to show good consistency with a cold
front arriving Thursday night and early Friday morning. Ahead of
the cold front on Thursday, partial sunshine combined with
veering, warm, low level flow will likely assist highs back into
the lower 70s, except possibly the immediate Red River area.
Scattered showers may occur within the better moisture across
Central Texas and areas mainly east of I-35 late Thursday night
and Friday with the well-advertised, shallow but strong arctic
cold front moving through. With the arctic cold front well east of
the better upper support and with the shallow nature of a very
dense and chilly airmass, we do not expect much in the way of any
tstorms at all. Now for the Friday period and into the holiday
weekend, which everyone is curious about. Model run-to-run
consistency both amongst the deterministic ECMWF/GFS/and Canadian
models continues to remain very high and differing quite a bit
from their ensemble means. Will we have very shallow cold air in
place?? The resounding answer is YES! However, these models and
their ensembles are struggling with position, strength, and track
(to an extent) of the Western U.S. upper trough. These parameters
can make all the difference in the world on whether we get all
rain, a wintry mix, ice, or nothing at all, especially areas west
of I-35/35W and north of Highway 380 to the Red River where colder
surface temperatures are expected to arise.

After all that verbiage, the conclusion is...we just DO NOT have
enough agreement and consistency with ANY of the medium range
models to say which scenario pans out with a very low confidence
on evolution. My gut feeling is somewhere winter impacts may occur
Friday into next weekend. However, I just do not have the
confidence to say to what extent north-south or east-west across
the area at this time with so much variability with the deep, mid
level longwave trough. As such, persistence was carried through
on the forecast with this period now entering into the end of our
7-day extended forecast. Be sure to stay informed from trusted
weather sources through the week and beware of what you read on
social media forums. We should see models coming more in line on
this system as we push through this week and the system becomes
better sampled by our upper-air network.

[TexasMetBlake]

Anybody else tossing the 18z? It makes no sense. Not only does it bring the front in a full day later (18z Saturday) but it's significantly warmer than any previous model and does away with the winter storm completely. That raises a bigger eyebrow than the 12z GFS that was blistering cold. This is comical.

The dam upstream is loading with cold. It's only a matter of time before it breaks free.

[Texaspirate11]

Anyone wanna comment on this???

[MontgomeryCoWx]

Anybody else tossing the 18z? It makes no sense. Not only does it bring the front in a full day later (18z Saturday) but it's significantly warmer than any previous model and does away with the winter storm completely. That raises a bigger eyebrow than the 12z GFS that was blistering cold. This is comical.

The dam upstream is loading with cold. It's only a matter of time before it breaks free.

Yeah I tossed it when I saw it hang up an Arctic front for 3.5 days over the TX/LA border. These fronts don’t do that and the accompanying SW Low retrogrades... it doesn’t do that either given the setup.

[Katdaddy]

Special Weather Statement
National Weather Service Houston/Galveston TX
824 PM CST SAT DEC 16 2017

TXZ236-237-170300-
Brazoria TX-Matagorda TX-
824 PM CST SAT DEC 16 2017

...STRONG THUNDERSTORMS MOVING NORTHEAST OVER MATAGORDA COUNTY...

At 824 PM CST, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles northeast of Markham to near Bay City
to Matagorda. Movement was northeast at 45 mph.

Winds in excess of 30 mph will be possible with these storms.

Locations impacted include...
Matagorda, Bay City, West Columbia, Sweeny, Sargent, Van Vleck, Wild
Peach Village, Wadsworth and Damon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

[snowman65]

The past 3-4 days of model hugging have been crazy, watching and wondering if we will see any wintry mischief. At this point now it looks like only a cold soaking rain....but I'm glad we aren't getting an ice storm...

[Katdaddy]

Special Weather Statement
National Weather Service Houston/Galveston TX
927 PM CST SAT DEC 16 2017

TXZ213-227-237-238-170415-
Brazoria TX-Galveston TX-Harris TX-Fort Bend TX-
927 PM CST SAT DEC 16 2017

...STRONG THUNDERSTORMS MOVING ACROSS GALVESTON...EAST CENTRAL FORT
BEND...BRAZORIA AND EASTERN HARRIS COUNTIES UNTIL 1015 PM CST...

At 925 PM CST, Doppler radar was tracking strong thunderstorms along
a line extending from Fort Bend Houston to near Lake Jackson.
Movement was northeast at 40 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Pasadena, Pearland, League City, southeastern Sugar Land, Baytown,
Missouri City, Galveston Causeway, Galveston Island West End, Texas
City, Friendswood, La Porte, Deer Park, Lake Jackson, Alvin,
Angleton, Dickinson, Stafford, South Houston, Bellaire and West
University Place.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

[TexasMetBlake]

00z GFS has BOMBED! Wintry weather to the gulf coast now and snow in New Orleans by Christmas. 1058+mb high building in out of Canada and the polar vortex setting up shop in the northern plaines with 480 thickness into Minnesota.

Don't get too attached. No model looks like the next but it's encouraging if you like cold weather.

[mckinne63]

Special Weather Statement
National Weather Service Houston/Galveston TX
927 PM CST SAT DEC 16 2017

TXZ213-227-237-238-170415-
Brazoria TX-Galveston TX-Harris TX-Fort Bend TX-
927 PM CST SAT DEC 16 2017

...STRONG THUNDERSTORMS MOVING ACROSS GALVESTON...EAST CENTRAL FORT
BEND...BRAZORIA AND EASTERN HARRIS COUNTIES UNTIL 1015 PM CST...

At 925 PM CST, Doppler radar was tracking strong thunderstorms along
a line extending from Fort Bend Houston to near Lake Jackson.
Movement was northeast at 40 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Pasadena, Pearland, League City, southeastern Sugar Land, Baytown,
Missouri City, Galveston Causeway, Galveston Island West End, Texas
City, Friendswood, La Porte, Deer Park, Lake Jackson, Alvin,
Angleton, Dickinson, Stafford, South Houston, Bellaire and West
University Place.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

We were at dinner, but we got a good bit of rain here in Stafford. When we left the restaurant just drizzling but still ponding on the roads and pool is now full!

[Heat Miser]

00z GFS has BOMBED! Wintry weather to the gulf coast now and snow in New Orleans by Christmas. 1058+mb high building in out of Canada and the polar vortex setting up shop in the northern plaines with 480 thickness into Minnesota.

Don't get too attached. No model looks like the next but it's encouraging if you like cold weather.

Blake, you know that'll change. I mean how many times have the models flip flopped in the last few days? So many times that not one person in this forum has any realistic idea what the weather will be in a week from now. We will know about two days from the commencement of the event, if an event is to occur. Models, models, models.

[Texaspirate11]

00z GFS has BOMBED! Wintry weather to the gulf coast now and snow in New Orleans by Christmas. 1058+mb high building in out of Canada and the polar vortex setting up shop in the northern plaines with 480 thickness into Minnesota.

Don't get too attached. No model looks like the next but it's encouraging if you like cold weather.

thank you but its also the GFS

[redneckweather]

Looks like the wintry weather across the state has been pushed back a few days now to around the 27th/28th and the Euro and GFS are both showing it. That is good but on the flip side they are pushing it back again and might push it on out of the forecast. Just a little food for thought.

[srainhoutx]

The coldest air in Canada this morning is currently in Eureka, Nunavut where it is -35.2 C. The actual air temperatures across most of the Canadian Prairies is in the - single digits C. Until I see some actual temperatures in the minus 30's across the Canadian Prairies further S near North Dakota and Montana, all this model manufactured cold air will keep me somewhat skeptical.

[wxman57]

Beware when the models (GFS here) keep pushing back the arrival of the winter weather. I always remind everyone to keep a sharp eye on the source region for this cold air. Generally, it comes from near the Pole or over western Canada. Sometimes, the extreme cold lies in Siberia. Cross-Polar flow drives it into western Canada then down the Plains to Texas.

Currently, temperatures are above-normal from western Canada, across the Pole, and across Siberia. If it's not cold there, then it can't get very cold here. I'm not saying we won't see any cold air here Christmas week. It's possible, but it has to develop to our north, first.

[jasons2k]

Happens every year. The 1983/89 freezeaggeddon is only two weeks away in the GFS... just two more weeks....

[srainhoutx]

I'll say this to be in regards to what all the guidance has been suggesting, if this cold is going to build across Western Canada we will know by Tuesday. That is when the strong disturbance currently over the Eastern Bering Sea/Western Alaska is expected to head ESE toward British Columbia and develop the strong trough the models have been predicting.

Meanwhile I have glanced at the overnight Ensembles and even the CPC Day 8+ GEFS Super Ensemble and those ensemble means are different that the Operational depictions of the GFS and the ECMWF. Cold air is there starting Tuesday (Western Canada) and heading S on Wednesday/Thursday into the Lower 48. There is quite a bit of moisture over Texas as well into the week after Christmas. Monday we will be 8 Days out until Christmas Day. If the guidance converges on a realistic solution by Tuesday/Wednesday, then and only then will confidence increase moderately regarding our sensible weather. Also a note of caution when looking at the Medium Range and beyond with those extreme heights (1060+ High Pressure). Those events are extremely rare. The strongest High Pressure ever recorded if I recall correctly was 1078mb over Alaska/Western Canada back in 1989, or maybe 1983.

[srainhoutx]

Sunday morning briefing from Jeff:


Active weather pattern remains in place across TX.

Passage of a surface low and strong upper level system Saturday evening produced widespread .5-1.5 inches of rainfall across the region. This system has moved eastward and out of the area, but the low level moisture axis has only barely pushed off the coast along a frontal boundary. Today should feature fairly calm conditions, but the surface warm front over the Gulf will begin to move toward the coast and inland on Monday. This combined with an approaching disturbance aloft will likely trigger scattered showers and thunderstorms on Monday as the warm front progresses northward across the region. Some of the storms could produce heavy rainfall given fairly high moisture levels.

A stronger storm system will move into SW TX late Monday into Tuesday and increase large scale lift over a developing warm sector air mass over SE TX. Surface warm front should stall somewhere near/north of College Station with a moist and increasingly unstable air mass over the region. Unlike the system on Saturday evening, much of the region should be in the warm sector with this next system. As lift increasing, expect showers and thunderstorms to increase some of which could be fairly strong. While wind shear once again looks favorable for some severe weather, clouds and fog over the warm sector may keep instability lacking preventing much on the way of severe weather. For what it is worth the NAM And GFS show nearly 1000 J/kg of CAPE by midday on Tuesday over portions of SE TX which would likely be enough instability for some severe weather. These cool season systems tend to not need as much instability. The severe threat will need to be monitored as we move into Tuesday morning to see how parameters are coming together.

Heavy rainfall also looks possible again on Tuesday as moisture levels rise to high levels for mid December. As long as storms keep moving and no sustained training develops, the flash flood threat should remain low. Grounds are more moist now than before the Saturday rainfall so run-off will be higher for the same amount of rainfall. Think the main threat will be minor street flooding where rainfall rates exceed local capacities, but some rises on area watersheds may occur. Rainfall totals of 1-2 inches look fairly likely across the area Monday-Tuesday with isolated higher amounts.

Late Week:

Much advertised arctic cold front still expected to arrive around Friday. Latest ensemble and actual runs of the major global models have greatly backed away from any sort of cut off upper level low over N MX over the Christmas weekend in favor of a more progressive trough passage. This appears to be a result of how energy breaks over the top of the large scale ridging over far NW Canada and the Arctic Circle. This results in a much drier post frontal air mass for next weekend. We shall see if this new trend of a drier post frontal air mass can hold for the next several model runs as this is the first general agreement in the large scale pattern toward next weekend from most of the models, but is a fairly significant shift from the previous runs.

Regardless, below normal temperatures look likely by next weekend as the strong frontal boundary pushes into the Gulf of Mexico.

Severe Weather Outlook Day 3 (Tuesday):

[Texaspirate11]

NORMAN NWS SEEMS TO BE OVER THE S WORD


NWS Norman‏
Verified account
@NWSNorman


"Blah blah blah SNOW blah blah blah."

Be honest, that's what you hear when the "S" word is spoken. This time, do us a favor and please read all the words in this forecast.

Thanks, Your humble night shift forecasters.

[GBinGrimes]

Personally, the model run hugging doesn't bother me in the least. None of the persons on this forum that moderate and post and have earned their credibility within this forum, and outside the forum, have stated that the return of 83/89 WILL HAPPEN.

If none of us wanted to obtain information of what could be possible, weather-wise, then this forum would exist in a less robust state and weather itself would be boring.

When my cold air loving weather brother in Montgomery County posts with excitement about the GFS being on track for 14 model runs in a row...I GET EXCITED. Excited because we have a place to share this together.

So, if there's in all actuality only a 5% chance that the Arctic Express arrives via a buckled jet stream, and we talk about it a lot, I'll take that chatter everyday over the benign winters of the past several years. At least there's a chance. Also, if someone wraps their pipes now, and the deep feeze doesn't arrive til late January, at least they've prepared.

Merry Christmas everyone!