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

[Roy]

WWA for north of DFW for almost too light to mention freezing drizzle, but it will finally get truly cold for a couple days.

[raindancewx]

Closing in on three full months without precipitation here. I was pretty worried about my analog blend for the month, but anomalies went toward the analogs over time. On the 20th, when the Northern Plains were +15, my "near average" idea for ND/MT/MN near Canada looked terrible, but since the 20th, an incredible correction began toward the analogs, in both the Northern Plains & Southeast where the signs were wrong v. what I forecast through 20 days. Will be curious to see how the final anomalies look

 

[aggiegeog]

The freezing line has cleared DFW and it marching through NE TX and northern C TX. Light score band is moving through N TX, many will see a dusting. Maybe someone gets a tad more than that. Otherwise watch for icy bridges as freezing drizzle wings out the last remaining moisture in the air. The next few days will be very cold with highs in the 20s and lows in the teens for most with single digits for a few.

[cheese007]

Reminds me of last year with bitter cold and hardly any moisture to work with

[DoctorMu]

It's snowing in Cleburne, freezing drizzle in Waco.

[aggiegeog]

31° here but note recent precip. Was in upper 30s this morning during the heaviest drizzle.

[raindancewx]

Did an experimental blend of the SOI drop (8-16 in Nov to <0 in Dec), low precip in Oct-Dec in ABQ, no precip in Dec in ABQ (pretty rare actually), and the US temperature anomaly profile for December to produce January. This is what I got - its a blend of 17 years, with 1951 (nada Dec, dry Fall), 1955 (US temp pattern Dec), 1996 (dry Fall, US temp pattern) weighted twice. Nada Decembers are rare since 1931 here, only 1950, 1956, 1963, 1981, 1996 - so for recency and comparable rarity that is given the same weight as the dry Falls.

[raindancewx]

The Canadian update is showing one of the biggest month/month trends toward wetness I've ever seen it do in the SW for February. Let's hope it shows it again next month. Might be reacting to the Nina falling apart in Nino 1.2, or the SOI collapse in December?

[cheese007]

Getting an actual snow shower in southwest Austin

[SeanBarg]

15 minutes ago, cheese007 said:

Getting an actual snow shower in southwest Austin

Roger that in SSW Austin as well. Flakes are getting large and quite impressive for a second snow event in Austin in a single month's time. Wasn't sure if the snowband would make it this far down to us but hell yeah! 

[vwgrrc]

Happy new year, guys!

The CPC's new release today showing a colder and wetter 2nd week of this month. I wouldn't be surprised  if we score something last next week.

[aggiegeog]

18 yesterday morning, 32 yesterday afternoon, 19 this morning. We are looking at upper 20s for highs if clouds hold or just above freezing if clouds break, some furries possible.

[aggiegeog]

We have ended our streak of below freezing temps at 68 hours at my house. 

The remainder of this week will feature lows still below freezing but highs in the 40s. We warm to near average for the weekend and early next week with chances for some rain. Then another cold shot for the middle of next week. Late next week looks to feature a big Southern Plains storm so we will watch where that sets up to see if we will be on the strong thunderstorm side or the wintery side or more likely some of both for northern Texas. After that we should warm to a bit above average generally for the latter half of Jan and early Feb though we should be wet during that time as the Pacific jet goes zonal. I expect we will see a return of the -EPO by mid Feb along with a + to -PNA. This would again bring cold air to the Southern Plains with a storm track from TX to the OH Valley. Mid Feb is is typically peak of the northern TX winter storm season.

[vwgrrc]

9 minutes ago, aggiegeog said:

We have ended our streak of below freezing temps at 68 hours at my house. 

The remainder of this week will feature lows still below freezing but highs in the 40s. We warm to near average for the weekend and early next week with chances for some rain. Then another cold shot for the middle of next week. Late next week looks to feature a big Southern Plains storm so we will watch where that sets up to see if we will be on the strong thunderstorm side or the wintery side or more likely some of both for northern Texas. After that we should warm to a bit above average generally for the latter half of Jan and early Feb though we should be wet during that time as the Pacific jet goes zonal. I expect we will see a return of the -EPO by mid Feb along with a + to -PNA. This would again bring cold air to the Southern Plains with a storm track from TX to the OH Valley. Mid Feb is is typically peak of the northern TX winter storm season.

Models begin to converge on the next week's Southern Plains storm. But that needs to expend 200 miles south for us to get anything significant.

[Roy]

78 hours below freezing IMBY. Pretty nice for this far south. No precip though aside from a light glaze and a few flurries (more snow grains). 

[SeanBarg]

In Austin we had 55 hours of below freezing temps end earlier today but we are back in the 20s tonight. A freezing drizzle/trace snow-sleet event last night helped bring the city to its knees as ice always does. Pretty neat to have 3 separate winter weather advisories in 4 weeks time but I'm ready for warmth again. 

[wxmx]

Colder than forecasted, and definitely wetter. Drizzle lasted for over 50 hours...nothing was forecasted until the very last minute. A few hours of stratocumulus snow were included (first I ever witnessed, you can see the rather uncommon sounding we experienced, you can even see in one of the pics that the higher elevations missed the snow) for a trace to small accumulations in places, plus freezing drizzle and freezing fog, making it the second event this far down this winter.

[raindancewx]

I'm getting really annoyed with this pattern - Monterrey, Brownsville, Houston, New Orleans, Tallahassee, Savannah have all seen snow before me this winter...and we haven't had any precip since Oct 5. It is neat to have a fairly cold winter for lows for once, that hasn't happened in a while, but I really hope the big storm the Euro shows next week verifies or we're going to have some major water issues here in Spring and Summer. I had 2005/2008 as analogs, and it was snowy in the South in 2008, and it was very dry here in 2005-06, but really was expecting other looks to the pattern which haven't shown up yet. Oh well, still time yet.

[aggiegeog]

Snuck in 19 here this morning to make 4 straight mornings in the teens.

[raindancewx]

GFS and Euro have a relatively similar solution for a storm around the 11th, maybe 0.2" to 0.5" for the city. Snow levels...probably above the city for most to all of the event but good for the mountains. Will change though. Hopefully the models still have it tonight. Its nice to see the GFS, which had nothing for the period, cave to the Euro which has had this for two-three days now.

[raindancewx]

The dewpoint has skyrocketed, all the way back to 30F...from 3 this time last night...but not looking like we'll get any measurable rain overnight. Close though, only missed by 20 miles or so. Of course...its 48 at 3 am as a result. 

Will be up to the next storm to break the dry-streak sometime Tuesday night into Wednesday.

 

[raindancewx]

The European, NAM, and GFS all have valley rain and mountain snow for NM this week. Tues/Weds cold see the end to the absurdly long stretch of days without precipitation. Would be a good snow event if the European verifies.

[aggiegeog]

The NM look to be on track for their first 6"+ snowfall of the season, finally, mainly falling on Wed.

[aggiegeog]

Friday morning has sneaky potential for wintery precip for E TX. Surface low over LA, closed upper low overhead and cold temps at the surface in January cannot be dismissed. We will be within NAM range for this tomorrow so that should show us if this is just Canadian model fantasy or if it is real.

[raindancewx]

The period for mid-Dec to mid-Jan will obviously be colder for the US, but for December itself, not really a cold month nationally. With a couple of modifications, December 1980 was a good match. I threw in 1943 & 2011 to make the Upper Midwest warmer, and 2012 to make the SE/NE warmer. You have "less" of a break in the heat in my analogs than this year in a couple spots (NW, SE, TX) but its close nonetheless.

 

[raindancewx]

I was playing with the observed SSTs in December for Nino 3.4 and Nino 1.2. Fairly strong correlations between Dec & the following March-May periods. I normalized the March-May periods against 1951-2010 means.

The conversion factors from December SSTs to MAM work out to -0.27C in Nino 3.4 for MAM, and -0.37C for Nino 1.2 in MAM. That configuration can be replicated with SSTs for MAM 1961, 1981, 1981, 1984, 2006. The configuration is based on correlations, which means they'll probably be off somewhat. To offset that, I ran 13 cases, where Nino 3.4 / Nino 1.2 come in near but not exactly at -0.27C and -0.37C. I then looked at subsurface conditions, and weighted each of the 13 scenarios at 1,2,5,10,15,25 points.

I re-produced all 13 scenarios using historical years with similar conditions, and then looked at the years that appeared most frequently in the higher weighted scenarios.

Given the subsurface looks like this, I assumed Nino 1.2 was more likely to come in colder than the correlation implies, while Nino 3.4 was more likely to come in warmer than the correlation implies. The scenarios that had Nino 1.2 warming massively relative to the correlation were thus weighted less, as were the scenarios that had Nino 3.4 cooling massively relative to the correlation.

Cases	MAM Risks		Points
Scenario	3.4	1.2	%
1	-0.67	-0.37	5%
2	-0.47	-0.37	5%
3	-0.27	-0.37	25%
4	-0.07	-0.37	15%
5	0.13	-0.37	10%
6	-0.27	-0.77	10%
7	-0.27	-0.57	15%
8	-0.27	-0.17	5%
9	-0.27	0.03	5%
10	-0.67	-0.77	1%
11	-0.47	-0.57	2%
12	-0.07	-0.17	1%
13	0.13	0.03	1%

Using those weights, I then did one final filter, adding three points to low solar years, and subtracting three points from high solar years for March-May to help sort out ties for weighting. A fair number of El Nino winters that were rapidly transitioning to La Ninas came up, will be interesting to see if we have the reverse of that. Anyway, the top 12 Springs were:

2006 (x4), 1984 (x3), 1981 (x3), 1961 (x2), 1977 (x1), 1963 (x1), 1986 (x1), 1978 (x1), 1988 (x1), 1960 (x1), 1973 (x1), 2003 (x1)

That blend is relatively close to what has happened in December, especially if you use Dec 8 - Jan 6 as December.

The long and the short of this is, the weighted blend is pretty wet for me in March, which hasn't happened since 2007. With my weights, solar factors, etc, the ONI would be -0.19C for Nino 3.4 in MAM, and -0.46C in MAM in Nino 1.2

Given the subsurface conditions, and the match to Dec 8 - Jan 6, plus my various simulations, fairly confident the map will look like below in MAM.

 

[aggiegeog]

Maybe just maybe NE TX can eek out a few flurries Thursday night on the backside of the surface low crossing LA. If nothing else hopefully the good rain shifts towards west towards E TX.

[aggiegeog]

Watch out for an extended period of light overrunning precip into Arctic air at the surface over eastern Texas for the middle of next week.

Or if the Canadian is to be believed we are on track for a big snowstorm. Difference being that the Canadian digs the 500mb trough SW while other models show it being progressive. The Canadian has been pretty solid this season though somewhat aggressive while the Euro has been all over the place and the GFS has been decent but inconsistent also. 

[aggiegeog]

NM mountains finally seeing a decent snow and most of NM and NW TX could see a bit of rain/snow from this system. The SW could finally cash in if the models are correct about the second half of the month having a -PNA.

[raindancewx]

My horrible dry streak was ended this morning - we got 0.03" of an inch of rain. First measurable precipitation since October 5, 2017, before we even knew who had a shot at the World Series or that there would be new tax policy for everyone.

Flagstaff's snow-free streak ended last night as well, and they got ~1/6 of their winter precipitation in about six hours, now at 50% of normal precip out there.