December-Wet/Stormy New Years Eve Ahead

[weatherguy425]

06z GFS keep with the couple run trend of a much weaker and progressive progression of troughs through Mid December, and is in Decent agreement with the more recent runs of the ECMWF. Also almost all ensemble guidance shows a decently positive NAO forming within the next week or so.Even up here in Lubbock we're expecting highs near 80 by this weekend. This time last year we were socked in with clouds and freezing drizzle, followed by our first snow on December 4th. Definitely a boring and depressing weather pattern for cold weather lovers, hopefully it will indeed change....SOON.

[Portastorm]

06z GFS keep with the couple run trend of a much weaker and progressive progression of troughs through Mid December, and is in Decent agreement with the more recent runs of the ECMWF. Also almost all ensemble guidance shows a decently positive NAO forming within the next week or so.Even up here in Lubbock we're expecting highs near 80 by this weekend. This time last year we were socked in with clouds and freezing drizzle, followed by our first snow on December 4th. Definitely a boring and depressing weather pattern for cold weather lovers, hopefully it will indeed change....SOON.

Don't despair too much. The GFS operational runs from the 0z and 6z cycles were a dramatic departure from the last few days. The ensembles from those cycles, especially the 6z cycle, still suggest the pooling and potential unleasing of cold Polar air late in the period (11-15 days).

Where did you see the ensemble guidance about the NAO? What I'm seeing is the NAO approaching neutral in 7-10 days but then going negative again at 14 days per the ensemble guidance.

[weatherguy425]

http://www.cpc.ncep.noaa.gov/products/p ... ions.shtml

This may be solely the GFS ensemble mean after taking another look at it. Though, it still indicates a substantial rise in NAO values, but as you indicated it does fall back toward neutral/negative territory by the middle of the month (maybe the 14th or so?). Though I've just seen these teleconnection signals looks very encouraging for quite some time in the loner granges, only for it to back off as we near the initial "progged" date. I guess I'm just being more guarded this winter, after how the pattern has been so far.

[srainhoutx]

I wouldn't get too worked up over the operational guidance swinging back and forth from run to run. Keep an eye on the ensembles for longer range pattern 'hints'. There remain some very strong indications via the CFSv2 guidance of changes ahead once we get beyond mid December. In fact the storm track may well bring some of the very cold air building in Western Canada S near/just before the Christmas Holidays. Enjoy the mild pattern while it lasts. Let’s just say I don’t think anyone E of the Rockies will be using the swimming pool for Christmas this year…

[weatherguy425]

Haha, I'm not saying it won;t happen. Just being extra cautious after jumping on the band-wagon when these indications first started appearing in the longer ranges around mid-November. I'm just going this comes to fruition before the 19th or so. I come home to Houston on the 19th; obviously my chances of winter precipitation are much greater up 'in these parts'.

[srainhoutx]

Haha, I'm not saying it won;t happen. Just being extra cautious after jumping on the band-wagon when these indications first started appearing in the longer ranges around mid-November. I'm just going this comes to fruition before the 19th or so. I come home to Houston on the 19th; obviously my chances of winter precipitation are much greater up 'in these parts'.

You never know. There many be slightly better chances for wintry mischief across Central/E TX/Louisiana than up in Lubbock this year. We will see.

[MontgomeryCoWx]

I freaking hate warm weather in December. Terrible!

[weatherguy425]

If your original thoughts on a southern Colorado storm track with an occasional coastal low comes to fruition, that definitely could be the case! Unfortunately

[wxman57]

12Z GFS indicates some quite nice weather here for the next week, at least. Great biking weather for the weekend, though still a bit chilly for my tastes. But who can possibly complain about high temperatures in the upper-70s to 80 degrees. Sure beats highs in the 40s or 50s for outdoor activities. Unfortunately, the 12Z GFS indicates lows dipping into the 40s again by the following weekend (Dec 8-9).

[srainhoutx]

The 12Z European Deterministic Guidance continues to advertise a piece of all that cold building across Western Canada heading S in about 10 days or so.

[weatherguy425]

Would be a nice time for the PNA to go positive and one of these Pacific pieces of energy to dig south and head east At-least I still have an imagination.

[JackCruz]

Sorry don't know how to resize the images.




Lord have mercy. I know this is probably not gonna happen, but can't help but wonder if there's a slim chance? Thoughts?


Regarding the pattern change, shouldn't we be experiencing the pattern change predicted last week(or 2 weeks ago) now or next week? But instead we're in the upper 70's - 80's. I've been living in Houston for 5 years now, one would think I'd get used to the flip flopping and what not...but I need cold and snow.

[Big O]

I shared this in another forum, but thought that reposting it in this thread was appropriate:

"I asked Fred Schmude with Impact Weather the following questions this morning. His answers provide promise for those of us who really like winter weather. See below:

Q: What would the various teleconnection indices have to look like for trough to be centered along central CONUS as opposed to being situated along east coast? Any chance of this happening?

A: If we see the East Pac and Atlantic Blocks set up a little farther to the west, then we could see the main trough axis set up shop right across the Plains. This of course would be good news for the Plains and Midwest because it would increase the likelihood of more rain/snow. Even though this is a possibility (~20%), the main favored position is still the Eastern U.S. and Canada.

Q: Any chance of a McFarland Signature setting up this winter?

A: This is the type of weather pattern where we could see something as extreme as a McFarland Signature bringing bitterly cold air all the way south to the Rio Grande Valley. Last winter the risk of that kind of a pattern was less than 10%...this year I put the risk at 20-30%. The best chance of a McFarland Signature will be during the last 10 days of Dec through Jan.

Keep hope alive!!!"

[srainhoutx]

Folks as the weather forum continue to grow and our members expand across Texas/Oklahoma/Louisiana, please take a moment and update your profile to include your general location. We are going to continue to expand our discussions for everyone well beyond the Houston Metro area. This was envisioned years ago by Dan and we took the growth of the forum in this regard when we received our new platform back in February 2010. It's good to see folks posting again and we look forward to many more taking the time to join us as we continue to make improvements with the platform in the future. KHOU recognizes the importance of our weather community and is being very active in updating and providing technical support as we continue to grow.

[Portastorm]

Here is an interesting snippet from the afternoon area forecast discussion (AFD) out of the NWSFO Austin/San Antonio (which is in New Braunfels):

A MUCH STRONGER FRONT AND ASSOCIATED UPPER LEVEL PATTERN CHANGE
TOWARD COLDER CONDITIONS APPEARS IN STORE FOR NEXT WEEKEND. WHILE
BEYOND OUR FORECAST RANGE FOR SPECIFICITY...OUTDOOR ACTIVITIES
WILL BE MUCH MORE PLEASANT THIS WEEKEND THAN NEXT...PLAN ACCORDINGLY.

[srainhoutx]

Here is an interesting snippet from the afternoon area forecast discussion (AFD) out of the NWSFO Austin/San Antonio (which is in New Braunfels):

A MUCH STRONGER FRONT AND ASSOCIATED UPPER LEVEL PATTERN CHANGE
TOWARD COLDER CONDITIONS APPEARS IN STORE FOR NEXT WEEKEND. WHILE
BEYOND OUR FORECAST RANGE FOR SPECIFICITY...OUTDOOR ACTIVITIES
WILL BE MUCH MORE PLEASANT THIS WEEKEND THAN NEXT...PLAN ACCORDINGLY.

Well the overnight 00Z Euro certainly agrees with EWX and their thinking. Looking at the longer range 06Z GEFS it does appear some mighty chilly air is poised to spill S into the Plains and bring some snow and wintry mischief fairly far S into the Southern Rockies/Southern Plains with some much needed cold rain closer to the drought parched regions of Central Texas. We will see.

11302012 00Z Euro 00zeuro500mbHeightAnomalyNH192.gif

11302012 06Z GEFS 00zgfsensembles500mbHeightAnomalyNH276.gif

11302012 06Z GFS Ensembles 06zENS11-15day850mbTempAnomalyNA.gif

[MontgomeryCoWx]

McFarland events of very cold air sound fun, but even a lot of the cold tolerant sub-tropical plants everyone knows and loves, like the fan palm trees, would suffer a massive die off. Not to mention pipes bursting in the such.


It is far better for a cool airmass, but not bitterly cold, with low dewpoints (although that means static shocks and itchy skin) , IMHO, for Winter fun. I have seen days in Dallas where 45ºF and sunny one afternoon is replaced by freezing/frozen the next via evaporative cooling, maybe with an assist of dynamic cooling. No airmass change, miraculous what a dewpoint in the single digits or teens can do, especially with a flow from the North to keep the dry recharge going so the airmass doesn't ompletely saturate and rise above freezing.

I have seen thunder-sleet storms before in DFW. Never here. Everyone should see thundersleet once in their lives...


BTW, a dewpoint thing, when I was in New York, a comfortable cool 45-ish day was never followed by Winter precip w/o an airmass change. Partly due to that stupid Atlantic Ocean. Speaking of, saw video from the old neighborhood in Nassau Shores, 4 blocks over, Stillwater Ave., homes on the bay had mechanical/wave damage, homes a block inland didn't have obvious mechanical damage, but had 3 to 5 feet of salt water flooding. Lots of sheet rock and carpets to rip out there.

I have been in two different wicked Thunder Snows/Sleets. One was in Longview, TX in 1989. I was out helping my Dad with the yard a few days before Christmas and it was 75. The cold front plowed through and that night it was 22 degrees with sleet/freezing rain and snow. You could see lightning and the thunders were roaring. We actually had a White Christmas that year although it didn't actually precipitate on Christmas Day.

The other ThunderSnow event was in Columbus, OH in 2006. Front swept through and Rain quickly changed to snow and 40 mph winds and snowbursts with thunder.

[David Paul]

Hi Arizona- I enjoy reading your posts. You bring up the subject of 'why' the models are so wrong and flip flop and the frustration that I'm sure many other people feel about the difficulties in long range, and sometimes very short range forecasting. The simple answer is that we do not yet completely (not even close to completely) understand the dynamics of the atmosphere. This means the computer models we use are imperfect to begin with. Also and probably more important, is that we have very little real data to initiate the model runs from. It's like taking a grain of sand and dropping it in a swimming pool. That grain of sand represents the two dozen or so weather balloon launches we get twice a day that give us real observed data to ingest into the models. Imperfect models and limited data equals increased forecast error over time. We have to work within our limitations and it is tough and very frustrating sometimes.

As for 'normal' weather.. it's actually quite rare to have a day that is normal. Usually, the temps or precip or winds are above or below normal on any given day or week or month, but average out over time to give us 'normal' readings for that day.

So we're in an imperfect model world with limited data points, things are rarely normal and nearly impossible to forecast accurately over time. That's the world the met must accept and work within some serious limitations. This is why I run a lot. Keeps my blood pressure low. Hope this helps. Cheers!

[jcarr]

Well AZ_ARIZONA_DESERT I wish someone could tell us all what the weather will be like with 100% accuracy. Unfortunately, weather will always be someone unpredictable. No amoutn of ranting can change that.

For everyone else that is interested...with a little bit or digging I have discovered that
AZ_ARIZONA_DESERT is actually a second member name for a regular poster on the forums. You see, you may be able to rejoin...but you cannot hide...you always leave a trail.

[srainhoutx]

Hi Arizona- I enjoy reading your posts. You bring up the subject of 'why' the models are so wrong and flip flop and the frustration that I'm sure many other people feel about the difficulties in long range, and sometimes very short range forecasting. The simple answer is that we do not yet completely (not even close to completely) understand the dynamics of the atmosphere. This means the computer models we use are imperfect to begin with. Also and probably more important, is that we have very little real data to initiate the model runs from. It's like taking a grain of sand and dropping it in a swimming pool. That grain of sand represents the two dozen or so weather balloon launches we get twice a day that give us real observed data to ingest into the models. Imperfect models and limited data equals increased forecast error over time. We have to work within our limitations and it is tough and very frustrating sometimes.

As for 'normal' weather.. it's actually quite rare to have a day that is normal. Usually, the temps or precip or winds are above or below normal on any given day or week or month, but average out over time to give us 'normal' readings for that day.

So we're in an imperfect model world with limited data points, things are rarely normal and nearly impossible to forecast accurately over time. That's the world the met must accept and work within some serious limitations. This is why I run a lot. Keeps my blood pressure low. Hope this helps. Cheers!

Thanks for the input David. How well we all know the challenges and limitations that the guidance provides you folks that forecast for a living. After all they don't call it guidance without reason. That said I remain somewhat optimistic that we'll see changes ahead near the mid December time frame.