Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 8

[bubba hotep]

FWD sounding pretty bullish on the cold and going for 20 at FWD:

Winds will lessen Thursday night and Friday morning as surface
high pressure becomes centered over southern OK. Light north winds
will be in place, and with clear skies and very dry surface air
(dewpoints in the low teens), favorable radiational cooling should
cause temperatures to plummet. Have drastically undercut guidance
once again on Friday morning with my only fear being that I didn`t
go cold enough. Current forecast lows at DFW and Waco are around
20 degrees which would be the coldest temps since January 2015.

[aggiegeog]

Man this month is setting up to be brutally cold. I would not be surprised to see us reach the single digits for the first time in 20 years and maybe challenge 83 and 89 if a good -EPO sets up. 

[Quixotic1]

2 hours ago, aggiegeog said:

Man this month is setting up to be brutally cold. I would not be surprised to see us reach the single digits for the first time in 20 years and maybe challenge 83 and 89 if a good -EPO sets up. 

I'm traveling so can't see.  What are the Euro and GFS saying?

[DFWWeather]

6 hours ago, bubba hotep said:

FWD sounding pretty bullish on the cold and going for 20 at FWD:

Winds will lessen Thursday night and Friday morning as surface
high pressure becomes centered over southern OK. Light north winds
will be in place, and with clear skies and very dry surface air
(dewpoints in the low teens), favorable radiational cooling should
cause temperatures to plummet. Have drastically undercut guidance
once again on Friday morning with my only fear being that I didn`t
go cold enough. Current forecast lows at DFW and Waco are around
20 degrees which would be the coldest temps since January 2015.

Yeah, they are, but the ECMWF has really backed off on the cold air today. Thinking maybe lows 23°F-25°F look more reasonable based on that, maybe even warmer. NAM is just coming into the picture. Basically what the GFS has been saying all along.

[DFWWeather]

2 hours ago, aggiegeog said:

Man this month is setting up to be brutally cold. I would not be surprised to see us reach the single digits for the first time in 20 years and maybe challenge 83 and 89 if a good -EPO sets up. 

 

12 minutes ago, Quixotic1 said:

I'm traveling so can't see.  What are the Euro and GFS saying?

The 0z GFS today had a very nice shot of Arctic air in the extended, however all runs after nothing. Operational ECMWF looks warmer across the board today...both runs. 12z ECMWF has a some Arctic air trying to nose down at 240h, but its H5 pattern won't allow it to get here.

[bubba hotep]

The models have been toying with dragging a weak disturbance through just behind the arctic front. The 12z Euro is back on this but keeps most of the snow off the west of DFW. The 12z Euro EPS has about 2/3 of the members with some variation of this impulse and a good bit get snow into DFW. It looks like the disturbance that the Euro is sniffing out is out in the Pacific north of Hawaii. The strength and timing of that still need to be pinned down and the orientation of the trough associated with the arctic blast needs to be worked out. Maybe something to watch finally?

 

[bubba hotep]

[DFWWeather]

Looks like the KDFW AFD from NWS this afternoon is still biting hard on the cold air with and even suggesting the possibility that DFW will fall below 20°F Friday morning. This has been more along my lines of thinking from the get go with this air mass. However, with the ECMWF coming in so much warmer today, not sure that can happen. Even if it does fall to at least 21°F or colder, it will be the coldest morning at DFW Airport since January 8, 2015. We actually reached 22°F in March 2015. Regardless, as long as we dip below 27°F, which I'm reasonably confident we should, it will be colder than all of last winter. Thursday should do the trick as well which keeps us below 40°F during the day, which we never did last winter.

[bubba hotep]

3 minutes ago, DFWWeather said:

Looks like the KDFW AFD from NWS this afternoon is still biting hard on the cold air with and even suggesting the possibility that DFW will fall below 20°F Friday morning. This has been more along my lines of thinking from the get go with this air mass. However, with the ECMWF coming in so much warmer today, not sure that can happen. Even if it does fall to at least 21°F or colder, it will be the coldest morning at DFW Airport since January 8, 2015. We actually reached 22°F in March 2015. Regardless, as long as we dip below 27°F, which I'm reasonably confident we should, it will be colder than all of last winter. Thursday should do the trick as well which keeps us below 40°F during the day, which we never did last winter.

I just glanced at things earlier but it looks like a trade off between solutions with warmer coming with a better chance of winter precipitation vs. a colder solution FWD. 

[aggiegeog]

8 minutes ago, bubba hotep said:

I just glanced at things earlier but it looks like a trade off between solutions with warmer coming with a better chance of winter precipitation vs. a colder solution FWD. 

Things seem to be coming in line with my original thinking of a system sneaking in behind the front. We will have to see if the mid level moisture can fill in as that is what was lacking when I looked at the models this morning. If we do get some frozen precip then Thursday afternoon and Friday morning would likely be colder than forecasted.

[raindancewx]

ONI value came in -0.8C for SON.

So...we have a weak Modoki La Nina, with the Eastern Tropical Pacific in borderline El Nino conditions (warm), a non-cannonical, but likely warm PDO (the warm ring and tongue are a bit off the historical norms for placement), and the AMO (ESRL long) came in at maybe the warmest value ever for November since 1856 (0.400 - didn't check - just eyeballed).

AMO is bad for moisture in the SW, Modoki La Nina is near average, and warm PDO is good for moisture. Not really a terrible set up for the winter, especially if the cold air spills into the east and cools the Atlantic as the La Nina weakens?

[aggiegeog]

Models are looking very interesting for snow tomorrow night. The mid levels are trending moister. If you assume the surface cools faster than models then that should further increase snow chances. It looks more like flurries than anything but still better than last winter.

[ams30721us]

37 minutes ago, aggiegeog said:

Models are looking very interesting for snow tomorrow night. The mid levels are trending moister. If you assume the surface cools faster than models then that should further increase snow chances. It looks more like flurries than anything but still better than last winter.

Quote

Area Forecast Discussion
National Weather Service Fort Worth TX
1105 AM CST Tue Dec 6 2016

.UPDATE...
Main update this morning was to remove mention of dense fog for
all of North and Central TX as well as to cancel the advisory
that was in effect. Added a mention of patchy fog/drizzle during
the overnight hours into Wednesday morning for areas south of
I-20. We also will monitor the potential for some light wintry
precipitation mainly south of I-20 and west of I-35 on Thursday
morning. More details on that will come with the full afternoon
forecast package.

 

[aggiegeog]

We are still following 1983 eerily closely. The absolute coldest air of that outbreak are unlikely, but an extended period of true Arctic air entrenching itself east of the Rockies seems likely later this month.

[Quixotic1]

2 hours ago, aggiegeog said:

We are still following 1983 eerily closely. The absolute coldest air of that outbreak are unlikely, but an extended period of true Arctic air entrenching itself east of the Rockies seems likely later this month.

If you go back and look at other ninas, December outbreaks seem to be prevalent.  Off the top of my head: 08, 05 (a dreadful winter), 00, 98(another awful winter), 95, 89, 88, 83.......there are exceptions such as 10 and 11.  Overall 

[bubba hotep]

From FWD AFD:

For late Wednesday into Thursday---Broad troughing should be
enough to assist any weak frontogenetical forcing to produce some
very light precipitation late Wednesday into Thursday. Both GFS
and ECMWF models output a fair amount of QPF just south of the
I-20 corridor and down through Central TX. While there is good
agreement in both of these models, the overall forcing appears
pretty subtle and as a result, I`ll trend on the lower side for my
PoP/QPF. If forcing becomes stronger/more apparent---it`s
possible that PoP/QPF will need to be adjusted in magnitude and
space. P-type forecast is difficult due to the uncertainty
revolving around the amount of lift juxtaposed with the best
moisture and cold air. As mentioned above, most NWP appears to be
too warm with regards to their hourly temperature output. In
addition, it`s likely that if precipitation is falling, more cooling
of the lower troposphere will likely continue. After closely
examining model soundings and discussion with surrounding offices,
I`ve added some wintry precipitation, mainly along and southwest
of an area bounded by an Eastland to Waxahachie to Waco to
Temple/Killeen line. Initial precipitation in the wake of the
front will start out as light rain/drizzle before transitioning to
light freezing/rain/drizzle. As the depth of the colder air
increases and secondary ice processes (seeder-feeder) begin to
dominate, a transition to light snow will be possible for the
aformentioned areas.

[bubba hotep]

The 12z Euro EPS had a bit of a NE trend with about 10 members getting the DFW area in on the action.

[aggiegeog]

1 minute ago, bubba hotep said:

From FWD AFD:

For late Wednesday into Thursday---Broad troughing should be
enough to assist any weak frontogenetical forcing to produce some
very light precipitation late Wednesday into Thursday. Both GFS
and ECMWF models output a fair amount of QPF just south of the
I-20 corridor and down through Central TX. While there is good
agreement in both of these models, the overall forcing appears
pretty subtle and as a result, I`ll trend on the lower side for my
PoP/QPF. If forcing becomes stronger/more apparent---it`s
possible that PoP/QPF will need to be adjusted in magnitude and
space. P-type forecast is difficult due to the uncertainty
revolving around the amount of lift juxtaposed with the best
moisture and cold air. As mentioned above, most NWP appears to be
too warm with regards to their hourly temperature output. In
addition, it`s likely that if precipitation is falling, more cooling
of the lower troposphere will likely continue. After closely
examining model soundings and discussion with surrounding offices,
I`ve added some wintry precipitation, mainly along and southwest
of an area bounded by an Eastland to Waxahachie to Waco to
Temple/Killeen line. Initial precipitation in the wake of the
front will start out as light rain/drizzle before transitioning to
light freezing/rain/drizzle. As the depth of the colder air
increases and secondary ice processes (seeder-feeder) begin to
dominate, a transition to light snow will be possible for the
aformentioned areas.

I was about to post that NWS offices are picking up on the wintery precip chances. Looks like the best chances are along I-20 generally with highest chance out west, but some chance in southern N TX and maybe a bit into E TX.

[bubba hotep]

10 minutes ago, Quixotic1 said:

If you go back and look at other ninas, December outbreaks seem to be prevalent.  Off the top of my head: 08, 05 (a dreadful winter), 00, 98(another awful winter), 95, 89, 88, 83.......there are exceptions such as 10 and 11.  Overall 

When I did that analysis last winter, IIRC, all the McFarland events that I analyzed occured during La Ninas. None occurred during El Nino.

[Quixotic1]

2 minutes ago, bubba hotep said:

When I did that analysis last winter, IIRC, all the McFarland events that I analyzed occured during La Ninas. None occurred during El Nino.

Yep.  Lets hope for 95-96, 83-84 or 00-01.  Some of the early 60 ones were monsters.

i am going to be pretty peeved if my flight tomorrow evening gets delayed....

[bubba hotep]

8 minutes ago, aggiegeog said:

I was about to post that NWS offices are picking up on the wintery precip chances. Looks like the best chances are along I-20 generally with highest chance out west, but some chance in southern N TX and maybe a bit into E TX.

We've gotten lucky in DFW in the past with these sneaky little disturbances that end up overperforming. You've been pretty steadfast that this was a possible solution. Now to track that little vort max to see if will tip its hand early.

[bubba hotep]

Now we wait for a NE trend that may never show:

[Quixotic1]

pretty sharp west to east cutoff on that graphic!

[aggiegeog]

8 minutes ago, bubba hotep said:

We've gotten lucky in DFW in the past with these sneaky little disturbances that end up overperforming. You've been pretty steadfast that this was a possible solution. Now to track that little vort max to see if will tip its hand early.

These are always tricky, but I have had a feeling that this was not going to be a classic blue norther for a while now though, maybe this will be one of my lucky ones. The trend is good.

[raindancewx]

It's been fun watching Accuweather's monthly outlook for my area. Went from 43.0F for a mean Dec high (Nov 30) all the way up to 50.0F (Dec 6). My Oct forecast had NM pretty warm/dry in Dec, which looks decent now even after the cold start. Certainly doesn't look like any major storms here through 12/16/16.

My general idea for this winter is the cold is in the MW/East in Nov-Dec (was mostly the SE in Nov) and then it retrogrades pretty to the West in January, and then it kind of centers between the Mississippi and the Continental Divide in February. We've been seeing pretty different setups to last year so far, and for all the warmth in the Super El Nino, Jan 1 - Jan 22 was pretty cold in the East in 2016. Would expect mild to warm temps in that period for them, with a colder West Coast.

 

[DFWWeather]

A full continental trough next week with air -30°C + sinking south, probably originating in Siberia. 1983, 1989 anybody? Though I must admit none of the operational models really bring it deep into Texas, at least not yet. 500mb ensemble means of the CMC, GFS, ECMWF look wicked though!

[bubba hotep]

41 minutes ago, DFWWeather said:

A full continental trough next week with air -30°C + sinking south, probably originating in Siberia. 1983, 1989 anybody? Though I must admit none of the operational models really bring it deep into Texas, at least not yet. 500mb ensemble means of the CMC, GFS, ECMWF look wicked though!

The 00z Euro has sub freezing highs for the DFW area next Thursday. Unlike this cold blast, there is stronger Euro EPS support with the ensemble mean nearly as cold as the operational. Also, the 00z Euro EPS shows another dump around the 18th. Beyond that, there is a pretty big spread but the colder side is some of the coldest I've seen on the Euro EPS this winter with members down in the single digits at DFW.

[aggiegeog]

Sure is looking like the 83 analogs that we have been hesitant to believe are proving true. I still doubt we are quite that cold but a slightly modified version sure looks possible. 

As for current weather the wintery precip potential looks as good as ever according to current models. We won't know how much precip will lag behind in the cold air until it is happening though. We are now getting into the range of the Hi-Res models so we should get a better handle on it as we go through the day.

[cheese007]

14 minutes ago, aggiegeog said:

 

As for current weather the wintery precip potential looks as good as ever according to current models. We won't know how much precip will lag behind in the cold air until it is happening though. We are now getting into the range of the Hi-Res models so we should get a better handle on it as we go through the day.

For the CS area or for DFW?

[aggiegeog]

6 minutes ago, cheese007 said:

For the CS area or for DFW?

Most likely between there and west.