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Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 6

Portastorm

By Portastorm,
in Central/Western States

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aggiegeog

aggiegeog

Posted
Posted

Some of those SE folks live to much on the cliff ready to jump at a single bad model run........ :cliff:

Yea, you can't do that. We have some great weather minds here in Texas that can keep you sane through the madness or 100s of model runs. I have learned to watch the 500mb pattern until it gets within about 3 days from that you can really get to know the patterns and what they generally result in for your area and also it is easy to see when the models are out to lunch.

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bubba hotep

bubba hotep

Posted
Posted

78-79? I know HM has that as one of his pets. A lot of people had 76-77 and that has been a pure D fail.

I think he might be trolling a little with'78 -79. Though, I think it shows up in the GWO analogs. Winter'76-77 actually looks pretty good based on PDO and MEI trends but December'14 isn't playing along. A winter that I have been mulling that I haven't seen in the common analog years being kicked around is '40-41. It is a decent PDO & MEI match, had a cold November and warm December. Then January was mild to warm before flipping cold in February. I'm dumping this from memory on the train so I could have this all whacked out lol

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bubba hotep

bubba hotep

Posted
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The GFS gives me no reason to doubt the coming weather. The Euro just has a progressive AK ridge and a slow to eject SW low. Maybe I am just optimistic, but the GFS pattern looks more likely. Now for the SE I could see how the SE ridge may shunt the cold away.

I'm really starting to like this timeframe but I've been swinging and missing all month! The Euro does tend to hold energy back in the SW too long. One encouraging trend, to me, is that tomorrow's system is trending wetter. It seems like the last 6 to 8 weeks we have seen everything dry up as systems moved towards reality (speaking N. Texas centric) maybe this will be the start of a wet streak for us

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DFWWeather

DFWWeather

Posted
Posted

I think he might be trolling a little with'78 -79. Though, I think it shows up in the GWO analogs. Winter'76-77 actually looks pretty good based on PDO and MEI trends but December'14 isn't playing along. A winter that I have been mulling that I haven't seen in the common analog years being kicked around is '40-41. It is a decent PDO & MEI match, had a cold November and warm December. Then January was mild to warm before flipping cold in February. I'm dumping this from memory on the train so I could have this all whacked out lol

I've posted this before a few posts back, and I know the signaling is not the same, but as far as analogs go, this year has been very, very similar to 1950-51, at least for DFW. Very warm October that year (hot really), just like this year. Record cold that year in November, some records set this year and low temps got to 22°F. That is 3 degrees from the 1950 all time record low of 19°F. Another Arctic dump occurred in early December of 1950, albeit a little later and stronger than the quick Arctic dump early this month. The rest of December was meh, just like now. The cold in early 51 held off until late January and came gangbusters with brutal cold into early February. Another weaker Arctic dump middle of February and then it let up. It'll be interesting to see what happens.

 

On another note, I wouldn't be surprised to see some ice pellets or wet snowflakes make it to the ground tomorrow. I know that NWS is against it from this afternoon's AFD, but 12z ECMWF really looking interesting.

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Quixotic1

Quixotic1

Posted
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I think he might be trolling a little with'78 -79. Though, I think it shows up in the GWO analogs. Winter'76-77 actually looks pretty good based on PDO and MEI trends but December'14 isn't playing along. A winter that I have been mulling that I haven't seen in the common analog years being kicked around is '40-41. It is a decent PDO & MEI match, had a cold November and warm December. Then January was mild to warm before flipping cold in February. I'm dumping this from memory on the train so I could have this all whacked out lol

I agreed with 76-77 as an analog. It looked great. Did the typhoon recurve disturb the pattern? I don't think so. Even in the beginning Cohen expressed concerns about the regression of the SAI after huge gains in the beginning of October. Something unprecedented. The Southern Plains is strongly correlated to the index so I worry that the expected perturbation of the PV hasn't happened.

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bubba hotep

bubba hotep

Posted
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I've posted this before a few posts back, and I know the signaling is not the same, but as far as analogs go, this year has been very, very similar to 1950-51, at least for DFW. Very warm October that year (hot really), just like this year. Record cold that year in November, some records set this year and low temps got to 22°F. That is 3 degrees from the 1950 all time record low of 19°F. Another Arctic dump occurred in early December of 1950, albeit a little later and stronger than the quick Arctic dump early this month. The rest of December was meh, just like now. The cold in early 51 held off until late January and came gangbusters with brutal cold into early February. Another weaker Arctic dump middle of February and then it let up. It'll be interesting to see what happens.

 

On another note, I wouldn't be surprised to see some ice pellets or wet snowflakes make it to the ground tomorrow. I know that NWS is against it from this afternoon's AFD, but 12z ECMWF really looking interesting.

 

I don't know a whole lot about that winter here in DFW but the PDO and MEI don't really match, so the "signaling" doesn't really match as you stated.  Also, the 500 mb and temp anomalies don't really work at the N. American scale.  Certainly some interesting comments regarding scale and how at the local resolution other factors can play a big difference.  

 

Yeah, we have gotten some nice slantwise instability out this way over the past several winters.  It would be cool to score a short burst of some sleet/hail out of this system. 

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Srain

Srain

Posted
Posted

The 00Z Parallel GFS suggests a 1054mb Arctic High in Wyoming at hour 192. This is before truncation and is noteworthy that the guidance tends to under estimate cold dense airmasses at this range. Also notice the storm nearing California. That is our New Years wintry mess that has been showing up via the Global guidance for a while now. The Euro, both versions of the GFS and the Canadian have been 'sniffing' this winter storm for a few days as we get into the range that may be valid. Time will tell.

 

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Srain

Srain

Posted
Posted

ABQ mentioning the New Years storm this morning. The 06Z GFS continued with the idea of a significant Winter Storm across the Southern half of Texas into Louisiana.

 

GUIDANCE THEN INDICATES A POTENTIALLY SIGNIFICANT WINTER STORM
SYSTEM EVOLVING VERY SLOWLY OVER THE AREA EARLY NEXT WEEK. THIS
ONE BEARS WATCHING AS PLENTY OF COLD AIR IS IN PLACE AND THE UPPER
FORCING IS NEARLY STATIONARY TO THE WEST OF NEW MEXICO FOR SEVERAL
DAYS. THE MOISTURE SOURCE WILL BE THE INGREDIENT TO QUESTION...BUT
THE POTENTIAL EXISTS FOR A BIG SNOW EVENT AROUND NEW YEARS.

 

 


 

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bubba hotep

bubba hotep

Posted
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ABQ mentioning the New Years storm this morning. The 06Z GFS continued with the idea of a significant Winter Storm across the Southern half of Texas into Louisiana.

 

GUIDANCE THEN INDICATES A POTENTIALLY SIGNIFICANT WINTER STORM

SYSTEM EVOLVING VERY SLOWLY OVER THE AREA EARLY NEXT WEEK. THIS

ONE BEARS WATCHING AS PLENTY OF COLD AIR IS IN PLACE AND THE UPPER

FORCING IS NEARLY STATIONARY TO THE WEST OF NEW MEXICO FOR SEVERAL

DAYS. THE MOISTURE SOURCE WILL BE THE INGREDIENT TO QUESTION...BUT

THE POTENTIAL EXISTS FOR A BIG SNOW EVENT AROUND NEW YEARS.

 

attachicon.gif12232014 06Z GFS 228 gfs_mslp_pcpn_frzn_us_35.png

 

attachicon.gif12232014 06Z GFS 240 gfs_mslp_pcpn_frzn_us_36.png

 

New Years is certainly starting to look at lot more interesting for Texas.  The soundings on Twisterdata (I know... long range soundings?!) seem to indicate that N. Texas would be pretty close to having the majority of this fall as snow.  However, it looks like a nasty ice storm to the south.  Obviously there is plenty of time for this to change but the overnight model runs were fun to look at. 

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aggiegeog

aggiegeog

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New Years is certainly starting to look at lot more interesting for Texas.  The soundings on Twisterdata (I know... long range soundings?!) seem to indicate that N. Texas would be pretty close to having the majority of this fall as snow.  However, it looks like a nasty ice storm to the south.  Obviously there is plenty of time for this to change but the overnight model runs were fun to look at. 

Just don't look at the PGFS which has all of a sudden lost the -EPO pattern for next week. All other models are looking like a significant winter storm for Texas around New Year's.

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aggiegeog

aggiegeog

Posted
Posted

Wow~ now looks brutal cold in DFW from 12/31 into the new year, but almost no percip by that time... :whistle:

Kinda of worry we get into the cycle: it's either too warm or no percip!

The CFS model is showing huge snow amounts across the state over the next month. Now I would not consider that a reliable forecast it does show that there is moisture and cold to be had.

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aggiegeog

aggiegeog

Posted
Posted

18z PGFS seems like a nice compromise between the 12z Euro and GFS. I doubt we will see a cutoff dropping down the Baja into the Pacific.

I agree, I think we will have cross polar flow bringing in sufficiently cold air by way of a high dropping down the eastern side of the Rockies and a digging trough into the Southwest slowly ejecting towards Texas just before New Year's.

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Srain

Srain

Posted
Posted

Evening briefing from Jeff:

 

Clear but cool Christmas…arctic outbreak and possible winter storm looms in the extended.

 

Potent storm system moved across the region this morning with a quick round of showers and even a few thunderstorms. Cold air advection continues this evening and on into Wednesday with clearing skies. Winds will keep temperatures from bottoming out tonight…mainly in the 40’s with highs only in the mid 50’s on Wednesday. Coldest night comes Wednesday into Christmas morning with mid 30’s and likely some lower 30’s over portions of the area under clear skies and light winds.

 

Christmas Day:

Surface high responsible for the current intrusion of cold air begins to move eastward on Thursday allowing onshore flow to resume. Cold start under clear skies will feature a good warm up into the lower 60’s for highs helped by sun and southerly flow.

 

Friday:

Probably the best day of the week temperature wise with lows in the 40’s and highs near 70 under increasing southerly flow. Clouds will start to increase ahead of a storm system for the weekend.

 

Weekend:

Next storm system will move across in the fast progressive flow aloft. Cold surface dome will only slowly modify and expect clouds and light rain to increase Saturday with the old surface front from today remaining offshore. A round of fog, drizzle, light rain seems likely Saturday and Sunday as the next system moves across and the surface cold pool hangs tough over the area. Models have been trending wetter and wetter with this system especially on Sunday so rain chances may need to be increased into the 60-70% range. Temperatures will be cool with both highs and lows regulated by clouds and rainfall to the 50’s and 40’s.

 

Next Week:

Upper air flow undergoes significant amplification with strong ridging building deep into Alaska resulting in the formation of a deep downstream longwave trough over the western and central US. Extremely cold air mass now of Siberia and northern Russia (-70 F wind chill today) will become entrained into the flow aloft and progress into NW Canada (the favored source region for US arctic air outbreaks) featuring temperatures in the -30 to -40F by the early to middle part of next week. With the trough in place over the western and central US, the arctic air begins to roar southward under the influence of a 1045-1055mb arctic surface ridge entering the US via Montana. The dense very cold air dams against the Rockies and spills southward straight down the front range into TX at a very rapid pace. True shallow arctic air masses almost always outrun model guidance and I think this event will be no different. Models are also almost always too warm with the air mass and undergo run to run temperature decreases as the event nears in the 48 hour time period. Don’t think we are looking at anything historic or record breaking with respect to the cold air, but a period of freezing and sub freezing temperatures is looking increasingly likely from as early as the 31st through the 2nd or even 3rd of Jan and this could include near freezing daytime highs. Intensity of the cold air is still subject of model disagreement, but once arctic air starts moving southward it is hard to stop it and the pattern certainly supports this.

 

Next and perhaps the bigger question is will there be any moisture in the post frontal arctic air. Forecast models have been off and on suggesting a portion of the upper trough hangs back over the SW US with a upper level flow out of the SW over the surface arctic air mass in place over TX. This would produce an overrunning pattern with warm air flow up and over the surface cold dome. Upper disturbances in this upper flow would help to enhance lift from time to time producing periods of precipitation. Long range forecast soundings show mostly a surface freezing layer with temperatures above freezing in the mid levels. P-type could be a potential issue from late on the 31st into the 2nd with the mostly likely precipitation being rain or freezing rain with the current suggested profiles. A fairly significant winter storm pattern is being suggested by the forecast models for the state of TX during this time period, but given how far out in time we are the fine details are beyond the limits of any forecasting certainty and more speculation. Much attention to be paid to this part of the forecast over the next several days.

 

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bubba hotep

bubba hotep

Posted
Posted

No model is reliable at that range with regards to snow. Still though, general forecast ideas can start to be gathered, which is what Srain's post from Jeff outlines.

Sent from my iPhone

 

Fortunately (or unfortunately) we don't have any hardcore weenies in this subforum thread that live and die on each model run and hug various snow maps like a kid on a Christmas morning.  I think pretty much everyone gets the jist of what is going on and knows what to look for.  This has been an interesting pattern to watch evolve, just a few days ago models were developing that Lakes bomb and kicking off a stout -NAO. Now the system is more progressive and the evolution doesn't break down ridging out East as fast and that is allowing the cold to dive down the spin of the Rockies and not bleed out as fast.  

 

There seems to be pretty good consensus on things now with one of the big differences being how the models handle the energy over the Lakes and NE heading into next week.  A lot can happen in a week (obviously) but the cold diving down into Texas around New Years seems pretty locked in at this point.  Now to watch how the models handle all the different pieces of energy and to see if we can get the snow cards to fall in our favor  :weenie:  :snowing:

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Srain

Srain

Posted
Posted

The ensemble mean supports the idea of leaving a positive tilted trough to our West. That usually spells over running with a very cold surface dome in place. The OP Euro is suggesting the Arctic front will arrive on the 30th. The various WFO's from New Mexico into Texas increased their 'chatter' this morning about the pattern changing to a much colder regime as we end 2014 and begin 2015.

 

 

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bubba hotep

bubba hotep

Posted
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The ensemble mean supports the idea of leaving a positive tilted trough to our West. That usually spells over running with a very cold surface dome in place. The OP Euro is suggesting the Arctic front will arrive on the 30th. The various WFO's from New Mexico into Texas increased their 'chatter' this morning about the pattern changing to a much colder regime as we end 2014 and begin 2015.

 

attachicon.gif12242014 00Z ENS 192 ecmwf-ens_z500a_namer_9.png

 

attachicon.gif12242014 06Z GEFS 192 gfs-ens_z500a_namer_33.png

 

What is your gut telling you Steve?  FWD just barely touched on the New Years forecast this morning:

 

THE GFS AND ECMWF SOLUTIONS DIFFER

ON HOW COLD IT WILL GET BY THE MIDDLE OF NEXT WEEK AS ANOTHER

TROUGH MOVES INTO THE WESTERN U.S. AND COLD AIR IN THE LOWER

LEVELS WORKS ITS WAY DOWN THE PLAINS. HAVE USED A BLEND OF THE

ECMWF AND GFS MODELS...BUT SOME VERY COLD AIR IS POSSIBLE FOR THE

END 2014 AND BEGINNING 2015.

 

Hopefully, we can get Cavanaugh on a slow night here soon and he will write up one of his epic discussions.

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