Texas Fall 2018

[Ntxw]

How much of that is terrain also? I would imagine that for somewhere like Atlanta or Birmingham, the cold air has to make it past the Ozarks and parts of the Smokies. Here, east of the Rockies, there's little but prairie for the cold air to pass over.

It's definitely all about terrain and geography. From the Northwest Canada to Texas is mostly downhill. While it is prairie and plains, the northern and central plains are higher than us. For example most of western Kansas is 2-3k feet up despite being flat. So if you can imagine the cold air just oozing slowly down a slope.

[bubba hotep]

Did someone say, stepping down? Early December looks fun!

I'd say more like stepping up into the money phases of the MJO....which, btw, we should see a lot of this winter - amped up 8-1!!!

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/diagram_40days_forecast_GEFS_member.gif

The +ENSO MJO composites for Dec are not actually that cold looking, which isn't surprising given that Dec is traditionally a warmer month during +ENSO events. The Euro isn't as amped and is faster, a blend of the Euro and GFS probably gets you close to what we have been seeing out of the MJO.



Both the Euro and GFS MJO forecast tend to favor a -NAO with the more amped up GFS tending to more strongly favor a -NAO.

[Ntxw]

I'm going to make a quick counter argument to the December Nino climo. I made a composite of all +ENSO in the new ONI subset (minus 1963 and 2009 being extreme cold outliers) and the 500mb pattern below.

Note your typical +ENSO Decembers do not feature a -NAO, in fact the opposite. A strong Alaskan trough and +NAO is favored in that climo. This December is likely to feature a negative NAO and AO unlike those years.


Here are the two very cold 1963 and 2009 Decembers.



So in conclusion, with the albeit small sample size, a -NAO/-AO in December during an El Nino is not very common.

[orangeblood]

Did someone say, stepping down? Early December looks fun!

I'd say more like stepping up into the money phases of the MJO....which, btw, we should see a lot of this winter - amped up 8-1!!!

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/diagram_40days_forecast_GEFS_member.gif

The +ENSO MJO composites for Dec are not actually that cold looking, which isn't surprising given that Dec is traditionally a warmer month during +ENSO events. The Euro isn't as amped and is faster, a blend of the Euro and GFS probably gets you close to what we have been seeing out of the MJO.


Both the Euro and GFS MJO forecast tend to favor a -NAO with the more amped up GFS tending to more strongly favor a -NAO.

But I've noticed lately, the Euro MJO forecasts have often been too fast and dampened...GEFS has led the way!!

[rwfromkansas]

This is a very good looking trough to give us at least a good shot at some rain is it not? Does it need to dig more? You would think there would be a lot of precipitation over us with this setup.

https://www.tropicaltidbits.com/analysis/models/gfs/2018112018/gfs_z500a_us_41.png

It's a decent trough, but on this run it is diving southeast from the mountain west in a positive tilt before rounding the base. The jet is split ahead east of us. To get a good soaker we need something to dig down California and into NW Mexico and really pump up Pacific moisture.

I understand what you’re saying now. And also I went and Googled some climo maps of precipitation after what you said about the climo being much wetter east of us. Yeah it’s no comparison. Living about 100 miles west of 35 seems pretty boring.

https://d32ogoqmya1dw8.cloudfront.net/images/eslabs/weather/us_ppt_1971-2000_456.png

I lived in the area of darker orange for six years. So friggin dry.

The only good thing? More ice and snow on average than here since the cold goes south faster, but still not often...I was too far south in Midland. If I was in Lubbock it would have been better.

I like it in DFW since I grew up in KS with roughly the same rainfall and climate, aside from the average 20 inches of snow and more winter cold.

[rwfromkansas]

How much of that is terrain also? I would imagine that for somewhere like Atlanta or Birmingham, the cold air has to make it past the Ozarks and parts of the Smokies. Here, east of the Rockies, there's little but prairie for the cold air to pass over.

It's definitely all about terrain and geography. From the Northwest Canada to Texas is mostly downhill. While it is prairie and plains, the northern and central plains are higher than us. For example most of western Kansas is 2-3k feet up despite being flat. So if you can imagine the cold air just oozing slowly down a slope.

You don’t need a 540 thickness in higher areas for snow either. IIRC when I lived in Midland 536-38 or so would do it often.

[bubba hotep]

DFW had another low deep in the 30s this morning at 34. While 30s may seem insignificant that is running -10F below the normal lows and we have been doing it on a consistent basis adding to the monthly departure. And for the past 12 days only 2 nights were close to normal and above 40, the rest were below 40. That's an amazing feat given urban heat island!

The avgs for this time of year at DFW are 65/44 and the 00z Euro EPS only shows 2 days that are avg or above avg over the next two weeks. This has been a solid cold snap since things flipped in mid-October.

[Ntxw]

Jamstec seasonal forecast for winter (November's data) is out and it is the coldest forecast it's had for DJF since 2009 for the US. It's been decent. It had one fatal flaw year being 2015 and went overly with Nino climo, but that was a Super event and can be forgiven anomaly.

[South Texas Storms]

Yep I was just discussing that with my long range coworker. We looked at the 500mb height anomalies, and it's textbook for cold across much of the country. The model shows consistent major blocking across northern Canada and the North Pole this winter.

[hamburgerman7070]

Ntxw, would you agree that the pattern may support more ice and sleet over snow if we see a winter storm later on? Sw flow over cold air. I guess isentropic lift? I thought I saw the gefs going into phase 1 pretty strong with mjo beginning of December

[Ntxw]

Ntxw, would you agree that the pattern may support more ice and sleet over snow if we see a winter storm later on? Sw flow over cold air. I guess isentropic lift? I thought I saw the gefs going into phase 1 pretty strong with mjo beginning of December

I'd make the argument it favors snow over sleet and ice. It's going to be all or nothing type winter rain to snow. 500mb heights are below normal across the south-central and southeastern US meaning air is colder up above than usual. It's the same reason storms are amplifying vs shearing out in a higher 500mb height regime. We may see several events this winter where above is colder and the surface is barely scratching 32-34F.

[Haris]

This is quite cool!

[bubba hotep]

I'm going to make a quick counter argument to the December Nino climo. I made a composite of all +ENSO in the new ONI subset (minus 1963 and 2009 being extreme cold outliers) and the 500mb pattern below.

Note your typical +ENSO Decembers do not feature a -NAO, in fact the opposite. A strong Alaskan trough and +NAO is favored in that climo. This December is likely to feature a negative NAO and AO unlike those years.

https://images2.imgbox.com/92/d1/UheMj5AG_o.jpg
Here are the two very cold 1963 and 2009 Decembers.

https://images2.imgbox.com/0e/40/Bv79w2Fv_o.jpg

So in conclusion, with the albeit small sample size, a -NAO/-AO in December during an El Nino is not very common.

'63 and '09 both ended up West based but they both had cold anomalies in the NE Pacific. The warm anomalies in the NE Pacific this year resemble '14 and it looks like '18 will continue to be West based +ENSO. There are no early winter SSW events in the ESRL data set for '63 or '09 but '09 saw increased 100mb poleward heat flux, similar to what we have seen so far in '18.

[bubba hotep]

Looks like we are headed for 100 pages in the Fall thread!

[Ntxw]

'63 and '09 both ended up West based but they both had cold anomalies in the NE Pacific. The warm anomalies in the NE Pacific this year resemble '14 and it looks like '18 will continue to be West based +ENSO. There are no early winter SSW events in the ESRL data set for '63 or '09 but '09 saw increased 100mb poleward heat flux, similar to what we have seen so far in '18.

2014 is a poor solar match though being maximum and the +PDO was very extreme. 2014 is also basically an early start to the bigger continuous Nino of 2015 and 2016, it was a very ++NAO winter overall. Really it was the Pacific that saved that winter late.



PDO values from JISAO, it is warmer but not at 2014 levels.

Code: Select all

2009**  -1.40  -1.55  -1.59  -1.65  -0.88  -0.31  -0.53   0.09   0.52   0.27  -0.40   0.08
2010**   0.83   0.82   0.44   0.78   0.62  -0.22  -1.05  -1.27  -1.61  -1.06  -0.82  -1.21
2011**  -0.92  -0.83  -0.69  -0.42  -0.37  -0.69  -1.86  -1.74  -1.79  -1.34  -2.33  -1.79
2012**  -1.38  -0.85  -1.05  -0.27  -1.26  -0.87  -1.52  -1.93  -2.21  -0.79  -0.59  -0.48
2013**  -0.13  -0.43  -0.63  -0.16   0.08  -0.78  -1.25  -1.04  -0.48  -0.87  -0.11  -0.41
2014**   0.30   0.38   0.97   1.13   1.80   0.82   0.70   0.67   1.08   1.49   1.72   2.51
2015**   2.45   2.30   2.00   1.44   1.20   1.54   1.84   1.56   1.94   1.47   0.86   1.01
2016**   1.53   1.75   2.40   2.62   2.35   2.03   1.25   0.52   0.45   0.56   1.88   1.17
2017**   0.77   0.70   0.74   1.12   0.88   0.79   0.10   0.09   0.32   0.05   0.15   0.50
2018**   0.70   0.37  -0.05   0.11   0.11  -0.04   0.11   0.18   0.09


Another little tid bit is that the Atlantic hurricane season is very busy this year, unusual for any El Nino. 1963 fits that bill most with similar ACE as this year. I've always believed the multiyear NAO tends to follow the fluxes of the solar cycles. We have a tendency to hit +NAO during maximum and -NAO during minimums. It's not a 1:1 correlation but I'll have to dig for papers that suggest such.

[DonWrk]

Hope this doesn’t make y’all jealous! On the honeymoon in Steamboat Springs balcony view!

(hope the image isn’t too massive in the post, was having heck trying to upload and post on my mobile)

[South Texas Storms]

The end of the 12z FV3-GFS shows a classic TX snowstorm developing. Cold air is in place across the state with a deep low pressure system approaching from Mexico.

The 12z GFS looks nothing like it.

[cheezyWXguy]

The end of the 12z FV3-GFS shows a classic TX snowstorm developing. Cold air is in place across the state with a deep low pressure system approaching from Mexico.

The 12z GFS looks nothing like it.

lol and neither does the 6z FV3

EDIT: the last 3 runs of the regular GFS do seem to show western trough pattern showing up in the long range though.

[bubba hotep]

Maybe the first significant system for Texas in a while? The last few runs of the Euro have been digging a system into the SW with decent opportunity for moisture return across Texas before the system kicks out across the state.

[TeamPlayersBlue]

I know -EPO is great for arctic blasts, but how is the -PNA/-AO combo for us? Would that be promising? As said above, a trough digging west of texas that tracks across the state would be the best orientation for moisture.