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

[aggiegeog]

Central and NE TX could see light freezing rain or a mix this evening. Tomorrow morning there will likely be a few winchills in the single digits across N TX with sub 20 wind chills for anywhere north of I-10.

[aggiegeog]

Any reports on what is reaching the ground west of I-35?

[raindancewx]

With the temperature down to 34F at 6 pm and low dew points, Albuquerque should be up to 11 nights of 32F or less since October 1 on 11/11. Tied with 1991 for fourth most since 1931 (10/1-11/11 lows of 32F or less).

[aggiegeog]

Central Texas got some sleet accumulations.

[aggiegeog]

19 yesterday morning and we are down to 19 as of 2am here.

[cstrunk]

Brrrr. I'm surprised it's this cold already and it's not even officially winter.

[aggiegeog]

This ties the coldest for November since I moved to my house in 2014 when it also got down to 17. Crazy though to have teens on consecutive mornings in early November. That is what a strong typhoon induced -EPO does though.

[aggiegeog]

Looks like the northern NM mountains will see feet of snow late this week potentially.

[raindancewx]

I like 10-30 inches for our mountains by Friday morning, and then maybe a bit more on Friday. Something like 1.00-1.25" at a 22:1 ratio for the highest mountains.

Not sure if it will verify, but my gut says there will be some dry bulb magic with this system late, and it might (briefly) snow down to 5,000 to 6,000 feet, with a quick inch even in Albuquerque on Thursday Night or Friday Morning.

[aggiegeog]

13 hours ago, raindancewx said:

I like 10-30 inches for our mountains by Friday morning, and then maybe a bit more on Friday. Something like 1.00-1.25" at a 22:1 ratio for the highest mountains.

Not sure if it will verify, but my gut says there will be some dry bulb magic with this system late, and it might (briefly) snow down to 5,000 to 6,000 feet, with a quick inch even in Albuquerque on Thursday Night or Friday Morning.

I agree with your analysis. The first big one of the season.

[raindancewx]

This would be a good little storm for Albuquerque - 24 hours through Thanksgiving Morning.

[cheese007]

15% contour added for parts of NTX up into Oklahoma on Black Friday. Not looking forward to it after what happened during the last event...

[aggiegeog]

This winter season looks great for snow in the area between I-25, I-35, I-70 and I-20 especially the NW half of that area.

[raindancewx]

I went with 1-4", 2-5", 4-8" for Albuquerque by elevation Wed-Thu tentatively - but may change tomorrow. The models all have at least some kind of transition to snow in the city late, it's just how quickly, and how much moisture. European keeps showing 6-12" for the whole city, which I think is way too high for most. NAM has 1-4" which I think is probably too low for some areas. GFS is 0-1", with hardly any rain even.

[raindancewx]

Albuquerque went from around 40F with a 12F dew point at 2 pm, to about 31F with a 25F dew point at 7:30, thanks to the magic of evaporative cooling. 

Some accumulating snow already where I am, with the airport already seeing some too officially.

[raindancewx]

Definitely a real snow storm here - this is I-25 and Paseo

Random Twitter pics - 

 

[raindancewx]

I had 7.5 inches of snow in my backyard with the Nov 27-28 storm. The airport had 3.9". The general totals city wide seem to have been 4-8 inches.

Mountain snow pack is in excellent shape as of this morning.

[Sydney Claridge]

I know we are only in a marginal risk zone, but the storm parameters over the DFW area look somewhat interesting right now.  Temperatures in the lower 70s (in places) with upper 60s dew points, in conjunction with some high helicity values (ESRH in the 300-500+ m2/s2 range), could produce some potentially severe storms if we can get storm initiation, though veer-back-veer seems to be an issue based on the change in wind directions between the 700mb and 500mb levels (based on the available SPC mesoanalysis data at the time of this post).

[raindancewx]

For the 2010s (2010-11 to 2019-20), snow frequency has really improved quite a bit over the 2000s decade. We're pretty likely to get several more snowy months by May so this graphic will have to updated when the eight month cold season is over, instead of just 1/4 over. 

If we finish the season above 13.5" snow - a coin-flip at this point - that 6.9" for the decade would match or exceed the 7.34" for the 2000s but without the heavy concentration of snow this decade in December 2006. We're already at four Oct-May periods with over 7 inches of snow in the 2010s (2011-12, 2014-15, 2015-16 2018-19), the 2000s had two (2000-01, 2006-07). We'll likely have a fifth in 2019-20 too.

Statistically, the seasons with at least two inches of snow in Albuquerque are far more likely to be snowy or even very snowy. None of the years with over two inches of snow in November have had under 5.5" for Oct-May. Years with at least two inches of snow in Albuquerque average 10.6 days with accumulating snow - all others are only 8.1. So we likely still have around 8-9 snowy days left here. We're about due for a season in the high-teens for snow here and it's ~4x more likely than usual now, although still less likely to happen than to happen.

[aggiegeog]

Models are showing some very interesting possibilities for the 13th-17th timeframe for the Southern Plains. Still much to figure out in regards to the evolution of a shortwave underneath the main West Coast ridge. Cold seems very likely, but there is potential for a heavy rain to ice and snow event along with the cold.

[It's Always Sunny]

1 hour ago, aggiegeog said:

Models are showing some very interesting possibilities for the 13th-17th timeframe for the Southern Plains. Still much to figure out in regards to the evolution of a shortwave underneath the main West Coast ridge. Cold seems very likely, but there is potential for a heavy rain to ice and snow event along with the cold.

-EPO/+PNA combo looks pretty good just depends how far south it allows that cold air to spill.  North Texas could be in for some FZRA if the QPF is there to support it on Sunday PM/Monday AM but GFS looks a bit dry with most of the precipitation to the east (actually where you are)...but it is the 264 hour of the GFS so we all know how little weight to put in that. 

[aggiegeog]

36 minutes ago, It's Always Sunny said:

-EPO/+PNA combo looks pretty good just depends how far south it allows that cold air to spill.  North Texas could be in for some FZRA if the QPF is there to support it on Sunday PM/Monday AM but GFS looks a bit dry with most of the precipitation to the east (actually where you are)...but it is the 264 hour of the GFS so we all know how little weight to put in that. 

Yep, I am intrigued enough the watch ensemble 500mb charts at least. The surface maps are fun, but only valuable to highlight possible scenarios not to base forecasts on.

[It's Always Sunny]

4 minutes ago, aggiegeog said:

Yep, I am intrigued enough the watch ensemble 500mb charts at least. The surface maps are fun, but only valuable to highlight possible scenarios not to base forecasts on.

At least the ensemble charts appear to latch onto the synoptic setup so I think it's safe to say we have the stage set for some winter weather in the Southern Plains depending on where you are.

[raindancewx]

I've been playing around with predictive variables for El Nino winter precipitation for Albuquerque. I've settled on a good blend. The average error in the hind-cast for precipitation is only 0.34 inches, with 93% of years within 0.80 inches (+/-).

Forecast blend is for 2.10" in Albuquerque for Dec 2019-Feb 2020, give or take 0.8". That kind of makes sense in the wake of six days in November with over 0.10" precipitation. Five of those were over 0.20". Long-term average for precipitation in winter is about 1.30", so the confidence is pretty high that the city will be at least somewhat above average, without hitting record precipitation (3.46") in winter either.

[aggiegeog]

There is a non-zero chance for snow Tues north of I-20.

[It's Always Sunny]

3 hours ago, aggiegeog said:

There is a non-zero chance for snow Tues north of I-20.

You mean zero chance of snow north of I-20? Going to be all rain here...

[cheese007]

So tired of 33 degrees and raining. So, so tired...

[raindancewx]

This winter should feature some good snow storms pretty far south. I think there are three mechanisms for that given what we've seen to date:

1) Exceptional dry air briefly overtakes an area, leading to very cold mornings...and then very wet subtropical/tropical air ends up on top of it. That 22F / -10 dew point air we had on Halloween Morning is probably going to combine with the subtropical jet at some point. We sort of had a version of it already here in late November, with the 20F / 12F dew-point morning turning into a 30F / 25F snow storm.

2) The Blue Norther of mid-November 2019 broke a lot of records from the legendary Blue Norther of 1911. I think its possible that setup returns one more time, but encounters more moisture from the subtropical jet.

3) We've had extended cloudy periods already in the SW this cold-season. If that continues in Dec/Jan, it will be eventually become very cold here, and that really puts the kibosh on any warm ups spreading to the east/north out of the Southwest. The cloudy periods are actually not great for valleys, we stay above freezing without the radiational cooling, but the mountains are only above freezing during the peak of the afternoon sun, so the cloudiness preserves the snow and cold higher up, which probably helps storms stay dynamic/cold as they pass through the Southwest.

[aggiegeog]

22 hours ago, It's Always Sunny said:

You mean zero chance of snow north of I-20? Going to be all rain here...

No I think there is a good chance for snow at the end along and north of I-20. Most won't stick but up around Paris to Texarkana I could see a couple spots getting over an inch quickly. If the surface high over the Plains comes in in the mid 1030s vs the modeled 1030ish then everything shifts to I-20 or south.

[It's Always Sunny]

3 hours ago, aggiegeog said:

No I think there is a good chance for snow at the end along and north of I-20. Most won't stick but up around Paris to Texarkana I could see a couple spots getting over an inch quickly. If the surface high over the Plains comes in in the mid 1030s vs the modeled 1030ish then everything shifts to I-20 or south.

Meh.  If that happens precip will likely get shunted further south so it wouldn't matter.  I think even if your scenario panned out lower levels will still be too warm unless it miraculously wet-bulbs to 0C.