Texas Winter 2017-2018

[Tammie]

NWS Fort Worth just introduced possible snow flurries for parts of NTX tomorrow night:
"Tomorrow's strong cold front will bring a chance for some snow/sleet mainly northwest of the Metroplex in the afternoon. Heaviest bands could result in some light accumulations. #txwx #dfwwx #texomawx"

[orangeblood]

Drastic differences for the 500mb forecasts between last nights GFS and Euro/Canadian runs...the Western Canadian ridge alignment is key to this winter storm potential - as you can see below, Euro much further north and west with the ridge (allowing energy to undercut the ridge/keeping cold and stormy potential in place next week) than GFS and could be the difference between a winter storm (Euro) and dry/northwest flow (GFS). Hopefully, we'll see more alignment today between the two models. The good news is I'd much rather have the Euro on our side at 144 hrs than the GFS

GFS


Euro

[orangeblood]

One of the more remarkable runs I've seen on last night's Euro Operational for North Central Texas

[Ntxw]

Drastic differences for the 500mb forecasts between last nights GFS and Euro/Canadian runs...the Western Canadian ridge alignment is key to this winter storm potential - as you can see below, Euro much further north and west with the ridge (allowing energy to undercut the ridge/keeping cold and stormy potential in place next week) than GFS and could be the difference between a winter storm (Euro) and dry/northwest flow (GFS). Hopefully, we'll see more alignment today between the two models. The good news is I'd much rather have the Euro on our side at 144 hrs than the GFS

GFS
https://www.tropicaltidbits.com/analysi ... mer_24.png

Euro
https://www.tropicaltidbits.com/analysi ... amer_7.png

GFS had it and then lost it. Euro's wheelbarrow is within 5 days. That's also when the Euro started correcting itself for the New Year's cold going back

[orangeblood]

Drastic differences for the 500mb forecasts between last nights GFS and Euro/Canadian runs...the Western Canadian ridge alignment is key to this winter storm potential - as you can see below, Euro much further north and west with the ridge (allowing energy to undercut the ridge/keeping cold and stormy potential in place next week) than GFS and could be the difference between a winter storm (Euro) and dry/northwest flow (GFS). Hopefully, we'll see more alignment today between the two models. The good news is I'd much rather have the Euro on our side at 144 hrs than the GFS

GFS
https://www.tropicaltidbits.com/analysi ... mer_24.png

Euro
https://www.tropicaltidbits.com/analysi ... amer_7.png

GFS had it and then lost it. Euro's wheelbarrow is within 5 days. That's also when the Euro started correcting itself for the New Year's cold going back

Yeah, we're about 2-3 runs away from better alignment (hopefully)

Side note: It's truly amazing that we've been saying the same thing re: accuracy of the models outside of 5 days for almost a decade now...particularly with all of the increases in computing power. It seems we've plateaued in that regard and is a true testament to one of the most complex systems on this planet (Mother Nature)

[Ntxw]

One of the more remarkable runs I've seen on last night's Euro Operational for North Central Texas

http://wx.graphics/models/ecmwf/2018011 ... st_240.png

That run whispers January 1978. The coldest month in DFW's history! For 6 days DFW was below freezing with on and off snow and ice

[EnnisTx]

One of the more remarkable runs I've seen on last night's Euro Operational for North Central Texas

Yes it is and this would definitely get us out of the winter weather rut!

[orangeblood]

Very interesting snow band coming together on the latest NAM, dissipates as it comes east but interesting nonetheless...to the FTW NWS office's credit, they've been discussing this for several days now even though the models had nothing really making it to the surface

[weatherdude1108]

EWX mentions a possibility of Winter mischief in about a week (as of this post).

000
FXUS64 KEWX 101005
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
405 AM CST Wed Jan 10 2018

.SHORT TERM (Today through Thursday)...
Lower level moisture return with associated low clouds and fog is
underway, was moving to the west at 15 mph just west of the I-35
corridor, though it will decrease its forward speed as it moves into
the Hill Country and toward the Rio Grande Plains. Visibilities were
slowly lowering. Expect areas of dense fog to develop and have
maintained Dense Fog Advisory through 10 AM along and east of I-35.
Patchy fog will linger until Midday. Patchy drizzle is possible this
morning. Expect mixing to mostly erode the stratus and fog this
afternoon leading to above normal temperatures all areas. An upper
level trough over Arizona moves into the Central Plains by Thursday
morning forcing a prefrontal trough into the Edwards Plateau and Rio
Grande Plains overnight. Lower level flow turning to southwesterly
along the I-35 corridor should keep patchy fog and drizzle east of
there late tonight into Thursday morning. A secondary trough moves
across Texas on Thursday forcing a cold front across our area late
morning into afternoon. There will be sufficient moisture for chances
of showers across eastern parts of our area with some instability
along the Highway 77 corridor for possibly isolated thunderstorms
late morning into early afternoon. The main impact of the front,
however, will be breezy to windy conditions in its wake as strong
surface high pressure builds into our area. Expect northwest winds of
20 to 30 mph along the Rio Grande with 15 to 25 mph elsewhere. Wind
gusts up to 35 mph or so are possible. The secondary trough will
bring some cloudiness to possibly hamper mixing of stronger winds
aloft. However, winds near advisory levels are possible. Another
impact is elevated fire weather conditions for areas west of Highway
281. Even though humidities are expected to remain well above 20
percent, windy conditions and cured fuels combine to bring elevated
fire weather conditions. Most areas will have high temperatures
around midday, then temperatures falling during the afternoon.

&&

.LONG TERM (Thursday Night through Tuesday)...
In the wake of the Thursday cold front and another cold front on
Saturday, temperatures become progressively colder. Freezes in the
Hill Country Friday become more widespread Saturday into Sunday
during the morning hours. The airmass will be too dry for any
precipitation late week through the weekend. Yet another cold front
is expected early next week, sometime during the late Monday into
early Tuesday time frame, depending on the model. All models show
isentropic lift developing on Monday and continuing through Tuesday
and will maintain slight to low chance POPs for rain showers. For
now, expect precipitation will end before temperatures fall below
freezing. However, if some continues as the ECMWF and GEM suggest,
then winter type precipitation may be possible beyond this forecast
for next Tuesday night into Wednesday.

[Ntxw]

12z Nam has a band of light snow cross DFW tomorrow afternoon/evening. Each run of late has increased further coverage and south

[downsouthman1]

Drastic differences for the 500mb forecasts between last nights GFS and Euro/Canadian runs...the Western Canadian ridge alignment is key to this winter storm potential - as you can see below, Euro much further north and west with the ridge (allowing energy to undercut the ridge/keeping cold and stormy potential in place next week) than GFS and could be the difference between a winter storm (Euro) and dry/northwest flow (GFS). Hopefully, we'll see more alignment today between the two models. The good news is I'd much rather have the Euro on our side at 144 hrs than the GFS

GFS
https://www.tropicaltidbits.com/analysi ... mer_24.png

Euro
https://www.tropicaltidbits.com/analysi ... amer_7.png

GFS had it and then lost it. Euro's wheelbarrow is within 5 days. That's also when the Euro started correcting itself for the New Year's cold going back

Yeah, we're about 2-3 runs away from better alignment (hopefully)

Side note: It's truly amazing that we've been saying the same thing re: accuracy of the models outside of 5 days for almost a decade now...particularly with all of the increases in computing power. It seems we've plateaued in that regard and is a true testament to one of the most complex systems on this planet (Mother Nature)

It's truly impossible to 100% accurately forecast a system as complex as weather, with all of its fluidity and moving parts. Just like sitting on a beach and watching a wave. Nothing can accurately predict what that wave will do.

[bubba hotep]

Pretty good support from the 00z Euro EPS & Control for the Op. Hmmmm

[wxman57]

... snip
Side note: It's truly amazing that we've been saying the same thing re: accuracy of the models outside of 5 days for almost a decade now...particularly with all of the increases in computing power. It seems we've plateaued in that regard and is a true testament to one of the most complex systems on this planet (Mother Nature)

Computer power only determines how quickly a model can be run, not how accurate a forecast will be. In order to predict the weather we need:

1. Equations that fully define the fluid atmosphere, taking into account all potential variables.
2. Quality input data. As the saying goes, "garbage in, garbage out". You cannot predict what the weather will do if the input data are not accurate or complete.

You could build a computer a billion times faster than anything we have today and it would not produce a better forecast if it uses the same equations and the same input data, but you'd get the output much faster.

[Ntxw]

Great post wxman57! One of the problem areas is initialization. You often hear around here how the models handle the Pacific determines what happens. The Pacific Ocean is one of the poor observed regions of the globe. Due to its vast size and lack of human traffic in the vast open waters to retrieve data for model input. We are often blind until a system hits the US mainland. The deserts of NW Mexico is another blind spot. The Atlantic on the other hand is well observed and traveled by aircraft to collect such data thus you will not see the great shifts of forecasts for the NAO as you would the EPO

[orangeblood]

... snip
Side note: It's truly amazing that we've been saying the same thing re: accuracy of the models outside of 5 days for almost a decade now...particularly with all of the increases in computing power. It seems we've plateaued in that regard and is a true testament to one of the most complex systems on this planet (Mother Nature)

Computer power only determines how quickly a model can be run, not how accurate a forecast will be. In order to predict the weather we need:

1. Equations that fully define the fluid atmosphere, taking into account all potential variables.
2. Quality input data. As the saying goes, "garbage in, garbage out". You cannot predict what the weather will do if the input data are not accurate or complete.

You could build a computer a billion times faster than anything we have today and it would not produce a better forecast if it uses the same equations and the same input data, but you'd get the output much faster.

Sorry, should've clarified.... when I say "Computing Power", I'm referring to the capacity to incorporate as many of the input variables as possible...this has drastically improved over the years but doesn't seem to translate into a much accurate depiction beyond 5 days or so. Shouldn't the accuracy of the input variables improve as we've added more satellites, reporting stations (ground or air), etc ??

[wxman57]

Great post wxman57! One of the problem areas is initialization. You often hear around here how the models handle the Pacific determines what happens. The Pacific Ocean is one of the poor observed regions of the globe. Due to its vast size and lack of human traffic in the vast open waters to retrieve data for model input. We are often blind until a system hits the US mainland. The deserts of NW Mexico is another blind spot. The Atlantic on the other hand is well observed and traveled by aircraft to collect such data thus you will not see the great shifts of forecasts for the NAO as you would the EPO

Yeah, the Pacific is a big void for the most part, and that's where most of our weather comes from. I'm hopeful that the next generations of weather satellites can help to fill at least some of that void.

As far as the weather across NE TX next Tue/Wed, I see the EC and Canadian aren't too far apart. I'm still thinking that moisture may be limited. I'm just not seeing a big snow event with the predicted pattern. Flurries more likely than a couple of inches. Hopefully we'll have a better idea by Sat/Sun.

[Ntxw]

GFS shifted south some from previous runs for tomorrow. Some northern burbs might see something. Again lift is strong and if more than modeled, might be a surprise for some lucky few



Lost in translation, this is a very powerful storm.

Not only that, guidance for many days ejected the leading wave in Oklahoma/Kansas, Colorado. Now closer to the permian basin. Only a few hundred miles to spare. Any further real time jogs S makes it more interesting

[Theepicman116]

I like the NAM 12km

[JayDT]

GFS shifted south some from previous runs for tomorrow. Some northern burbs might see something. Again lift is strong and if more than modeled, might be a surprise for some lucky few

http://i68.tinypic.com/29vazh4.png

Lost in translation, this is a very powerful storm.

Not only that, guidance for many days ejected the leading wave in Oklahoma/Kansas, Colorado. Now closer to the permian basin. Only a few hundred miles to spare. Any further real time jogs S makes it more interesting

I really hope that precip can be 30-50 miles further south.. I’m desperate at this point lol

[JayDT]

If the NAM is showing something for all of the DFW area, then im all for the NAM too