Texas Winter 2018-2019

[Cpv17]

This looks like the WPC is following the GFS more so than the Euro.



Also, looks to be on the conservative side.

[bubba hotep]

Last 3 runs of the GFS at DFW - 6.5", 10", 7". Those kinds of totals would put the '15 record in jeopardy.

[Ntxw]

The models overnight especially the Euro and group are definitely encouraging. Still about 2-3 days more until the new cold air enters the US as well as the storm crashing into shore. Also about the time we get into 100 hours and that's when we can start focusing on what kind of precip and where/how much.

It seems to me on the models is time for bowling season. Digging troughs with big cutoff lows are signature El Nino and slowly, but surely, we are going that path.

[bubba hotep]

06z FV3 a tick south of 00z

[Cerlin]

06z FV3 a tick south of 00z

https://www.tropicaltidbits.com/analysis/models/fv3p/2018120306/fv3p_asnow_us_40.png

I’m sorry, does that say 17 inches??

[Ntxw]

Also longer range there is now nearly universal agreement between the models of a stratosphere PV displacement during the mid month warm up in the Continent, Texas is only in the outer fringes and actually will get a barrage of storms during this period. Look for the later third of the month to return to cold, potentials with a -> -NAO (Scandinavian) -> -AO (Greenland) and eventually a -EPO (Alaska) with an Aleutian trough slinging storms at us.

El Nino reading this morning is +1.2C

 https://twitter.com/MJVentrice/status/1069408019019120641

[gboudx]

Morning update from Jeff Lindner:


A significant storm system is likely to impact TX late this week and this weekend

An upper level storm system currently off the NW coast of the US will dig SSE and into the SW US and N MX over the next 48 hours and then turn eastward and move across TX late this week. Surface high pressure building into the area this morning will bring fair cool-cold weather today-Wednesday. By Wednesday this high pressure will begin to move eastward allowing SE winds to bring moisture back into the area from the Gulf.

Moisture increasing rapidly early Thursday and expect to see an increase in clouds and then showers by the afternoon and evening hours.

Friday/early Saturday:

A powerful dynamic storm system will move into TX and interact with near record moisture levels over the region. Early Friday morning a slow moving cold air mass will be pushing southward through NW TX. While the surface high helping to guide this cold air mass is situated more over the Great Lakes, the density of such air masses tend to move southward faster than global models indicate…so the actual front could be deeper into the state by early Friday morning than the current global models are suggesting. Where this front is during the day on Friday will be important as it will be the focus for sustained heavy rainfall production.

Strong lift comes to bear across the region Friday into Friday night with widespread showers and some thunderstorms. Currently instability is looking limited, but experience with cool season severe weather events indicate that not a lot of instability is needed along the Gulf coast this time of year to produce severe weather. Of much greater concern is the threat for heavy rainfall as moisture levels rise to near record levels by Friday afternoon as both Gulf and Pacific moisture taps evolve over the area. PWS will increase to near 1.7-1.9 inches which is near the top maximum values for early December and represent moisture more typical of summer than early winter. Those type of moisture values combined with such a dynamic upper air system and a slow moving frontal boundary are strongly pointing toward some sort of heavy rainfall event. Additionally, the formation of a surface low pressure system near/over SE TX Friday afternoon/evening into Saturday morning also raises the threat for heavy rainfall.

There is uncertainty on where the actual frontal boundary will be located Friday and Friday night as this and the track of any surface low will support the maximum rainfall totals in that area. Currently the GFS is focusing the heaviest rainfall just north of our area while the ECWMF and CMC and across much of the northern half of SE TX.

Rainfall Amounts:

While it is still early, widespread rainfall amounts of 2-4 inches look possible with isolated much higher amounts. These totals will likely need to be adjusted in the coming days as forecast confidence increases on where the heaviest rain will fall. Rainfall amounts of this magnitude over a large area will likely result in run-off into area creeks and rivers and result in rises.

[rwfromkansas]

Road trip to my wife’s family in Abilene if that run verified. Lol

[gpsnowman]

So close to being an I-20 special. Hopefully the models continue to show a southern track as the week progresses. Would be a great surprise for DFW. My main concern is the cold air.

[Ralph's Weather]

So close to being an I-20 special. Hopefully the models continue to show a southern track as the week progresses. Would be a great surprise for DFW. My main concern is the cold air.

Agreed, I do think that backside snow on Saturday is fairly likely, but if we could get the cold air down here on Friday that is when things could get wild.

[spencer817]

So close to being an I-20 special. Hopefully the models continue to show a southern track as the week progresses. Would be a great surprise for DFW. My main concern is the cold air.

Agreed, I do think that backside snow on Saturday is fairly likely, but if we could get the cold air down here on Friday that is when things could get wild.

Why do you think models are struggling to show that?

[Ntxw]

So close to being an I-20 special. Hopefully the models continue to show a southern track as the week progresses. Would be a great surprise for DFW. My main concern is the cold air.

Agreed, I do think that backside snow on Saturday is fairly likely, but if we could get the cold air down here on Friday that is when things could get wild.

Why do you think models are struggling to show that?

I pulled the GFS run on Thursday compared to this morning. The struggle has been real. What's 500-700 mile difference? Still some days yet more to go with trends. Once we get inside high resolution is when you'll likely see the biggest shifts.

[gpsnowman]

So close to being an I-20 special. Hopefully the models continue to show a southern track as the week progresses. Would be a great surprise for DFW. My main concern is the cold air.

Agreed, I do think that backside snow on Saturday is fairly likely, but if we could get the cold air down here on Friday that is when things could get wild.

Why do you think models are struggling to show that?

Well the cold and the storm are not quite close enough for a wholly accurate analysis. All we know at this point is it will be wet with cold air around. Give it a couple days and then some North American sampling will occur to give us a better idea of magnitude of the cold air mass. Things in our favor include models sometimes underdoing the temps this far out and a decent snow pack up north leading to less moderation of the air mass. At worst a cold rain will greet us late this week.

[Ntxw]

Here is a composite of QPF trend from the GFS. Notice the shrinking of qpf in Kansas, Missouri, and Oklahoma. This is the worry for those north of the Red River. That ominous gulf low is lurking.

[spencer817]

Here is a composite of QPF trend from the GFS. Notice the shrinking of qpf in Kansas, Missouri, and Oklahoma. This is the worry for those north of the Red River. That ominous gulf low is lurking.

https://images2.imgbox.com/09/22/k8QYUm4g_o.gif

Could a QPF shield further south allow more cold air to come quicker, or while the storm is occuring?

[Ntxw]

Here is a composite of QPF trend from the GFS. Notice the shrinking of qpf in Kansas, Missouri, and Oklahoma. This is the worry for those north of the Red River. That ominous gulf low is lurking.

https://images2.imgbox.com/09/22/k8QYUm4g_o.gif

Could a QPF shield further south allow more cold air to come quicker, or while the storm is occuring?

Not necessarily. You have to take into consideration what is happening upstream. A weaker system at 5h will have a more suppressed track. At the same time its SW flow influence is less, thus less warm air advection. Also interactions with the northern jet is also at play. The lesser QPF is both a result of gulf low influence as well as more cold/dry air moving south. We are not yet in range of those players being on the field yet. Everything is just on paper.

[Brent]

the 12z Euro definitely doesn't look as wintry as the 0z, snow is more confined further NW through Saturday more like the GFS

[Haris]

Wettest euro yet. 5” here

[starsfan65]

the 12z Euro definitely doesn't look as wintry as the 0z, snow is more confined further NW through Saturday more like the GFS

Has the EURO caved in to the GFS?

[bubba hotep]

the 12z Euro definitely doesn't look as wintry as the 0z, snow is more confined further NW through Saturday more like the GFS

Has the EURO caved in to the GFS?

Models are shifting around within the ensemble spread. The 12z GEFS & 00z Euro EPS basically show zero winter wx scenarios for DFW with northward shifts being more likely (based on ensemble cluster analysis).