Texas Fall 2013

[orangeblood]

I scanned my 72hr prog from 00Z Nov. 22, 1993 and compared it to lasts nights prog for the same date - 00Z Nov 25th of this year. On my old 72hr prog is where the Arctic front was at 00Z on the 25th. Note what I called the chart at the top.

haha, yes that was one of the more memorable holiday storms for me.

What concerns me, when comparing to 1993 setup, is the polar jet is shifted 500 miles to the southwest this time around which pushes the HP off to the east too quickly - so in other words I'm worried about 1) there being enough cold air advection and 2) wind direction shifting to the east-southeast by the time the bulk of precip comes through bringing warmer air with it. In 1993, the cold air advection got stronger as the event progressed while it will be opposite this time around

[downsouthman1]

I scanned my 72hr prog from 00Z Nov. 22, 1993 and compared it to lasts nights prog for the same date - 00Z Nov 25th of this year. On my old 72hr prog is where the Arctic front was at 00Z on the 25th. Note what I called the chart at the top.

haha, yes that was one of the more memorable holiday storms for me.

What concerns me, when comparing to 1993 setup, is the polar jet is shifted 500 miles to the southwest this time around which pushes the HP off to the east too quickly - so in other words I'm worried about 1) there being enough cold air advection and 2) wind direction shifting to the east-southeast by the time the bulk of precip comes through bringing warmer air with it. In 1993, the cold air advection got stronger as the event progressed while it will be opposite this time around

That's true but the ULL will contain enough of it's own cold air. It's direct path will be very important.

[orangeblood]

I posted a link earlier in this thread of dec 4th 1988 i believe. Look at that analog. Very very similar to this weekend. Check it out.

Not finding the similarity with that one, a big Rocky Mountain ridge was dominate around that time period

[orangeblood]

I scanned my 72hr prog from 00Z Nov. 22, 1993 and compared it to lasts nights prog for the same date - 00Z Nov 25th of this year. On my old 72hr prog is where the Arctic front was at 00Z on the 25th. Note what I called the chart at the top.

haha, yes that was one of the more memorable holiday storms for me.

What concerns me, when comparing to 1993 setup, is the polar jet is shifted 500 miles to the southwest this time around which pushes the HP off to the east too quickly - so in other words I'm worried about 1) there being enough cold air advection and 2) wind direction shifting to the east-southeast by the time the bulk of precip comes through bringing warmer air with it. In 1993, the cold air advection got stronger as the event progressed while it will be opposite this time around

That's true but the ULL will contain enough of it's own cold air. It's direct path will be very important.

Yeah, whats crazy about this system is that we could go from rain,freezing rain to sleet back to rain and end as snow on Tuesday when the ULL passes over the area

[wxman57]

12Z GFS is colder for Dallas-Ft. Worth. High in the low 30s with precip all day Monday.



Cold here, too:

[gboudx]

Sounds like it would be a traveling nightmare if that verified for DFW. At least schools will be out.

[Tireman4]

I scanned my 72hr prog from 00Z Nov. 22, 1993 and compared it to lasts nights prog for the same date - 00Z Nov 25th of this year. On my old 72hr prog is where the Arctic front was at 00Z on the 25th. Note what I called the chart at the top.

http://home.comcast.net/~cgh57/1993.gif

Nice name. All Cowboys fans who saw that game will remember what Leon Lett did that day on the sleet covering the Texas Stadium field.

Could not leave the ball alone. Just could not leave it alone. Aiigghhhhhh!!!

[TeamPlayersBlue]

I posted a link earlier in this thread of dec 4th 1988 i believe. Look at that analog. Very very similar to this weekend. Check it out.

Not finding the similarity with that one, a big Rocky Mountain ridge was dominate around that time period

Wrong date it was 12-9-1988

http://www.meteo.psu.edu/~fxg1/NARR/1988/us1209.php

Also, you mentioned earlier how the polar jet is 500 miles more southwest than the 1993 system, due to this it ejects east quicker, why is this? Thanks and i really enjoy your input.

[joshskeety]

Newest weather models have not just sleet this weekend, but if the models are right then looks like PURE SNOW starting Sat night all day through Sunday for Ft. Worth westward. Latest NAM at 60-84 hrs at the 7AM Model run looks BRUTAL showing 6-10 inches of snow.. Now, Im sure the precip is overblown but a 3-6 inch snow this weekend would be a significant event.. Only thing is if warm air is injected at <5000 feet elevation where the 850mb line is stated on the model. Saw this a few times living in Virginia where the warm air injection would be just 1,000 to 2,000 feet high creating sleet when the 850mb line was solid frozen, creating a horrible ice storm when all the Mets were calling for all snow.. I think DFW is too high in elevation (1000 feet to 500 feet depending on location) to get that skew, but it remains to be seen. Will be interesting to get a look at the full atmos graph for Ft. Worth and Weatherford to see if the 7AM NAM run is fully supporting a snow event or just a heavy sleet event.

Just looked at the Skew-T's for DFW and FTWM and Weatherford.. DFW still shows a warm nose at 4,000 feet on the 12z run, however FTWM and Weatherford both show below freezing on all levels of the atmosphere. Will be interesting to see how the NWS in FTW will play this forecast. The only issue is since the 6z and 12z runs have both trended cooler if this continues through the runs it will allow more dry air and may cut off precip entirely quickly and most of the area gets a dusting and DFW is in the upper 20's low 30's on Sunday/Monday..

BTW, been a while since I have been at this forum.. Good to be back..

[downsouthman1]

12Z GFS is colder for Dallas-Ft. Worth. High in the low 30s with precip all day Monday.

http://home.comcast.net/~cgh57/dfwgfs12znov21.gif

Cold here, too:
http://home.comcast.net/~cgh57/iahgfs12znov21.gif

The GFS is usually warm. Interesting to see this out of it.

[joshskeety]

Also, does it seem to anyone else that this cold front is much colder than the models predicted and seems to be picking up steam? Just another observation...

[orangeblood]

I posted a link earlier in this thread of dec 4th 1988 i believe. Look at that analog. Very very similar to this weekend. Check it out.

Not finding the similarity with that one, a big Rocky Mountain ridge was dominate around that time period

Wrong date it was 12-9-1988

http://www.meteo.psu.edu/~fxg1/NARR/1988/us1209.php

Also, you mentioned earlier how the polar jet is 500 miles more southwest than the 1993 system, due to this it ejects east quicker, why is this? Thanks and i really enjoy your input.

Pretty good analog, it's colder with this setup than back in December 1988

Not necessarily, the biggest factor to eject the ULL system out is the tanking EPO (Eastern Pacific Oscillation). Notice in the chart below the transition to negative over the next 48 hours - that usually forces systems to progress out of the west coast instead of sitting there.

[Longhornmaniac8]

wxman, could you do a GFS meteogram for Austin?

Thanks,
Cameron

[joshskeety]

The 12z GFS seems to suggest more towards the current forecast of the NWS which is more towards the sleet/ice for the western counties of the metroplex and maybe some sleet towards the end of the event late in the evening Sunday for the whole metroplex.. The GFS skew's are most definitely warmer and show a warm nose all the way up to the Oklahoma border where I stopped checking..

Once again, 2 models showing vastly different things, but so far according to the DFW meteo's they are sticking with their forecast so obviously they are hedging their bets with the GFS over the NAM..

The NAM seems to suggest even sleet/snow as far south and east as Tyler and Paris Texas.. Not sure if I can buy that just yet for myself.. Either way, Im going hunting this weekend regardless of the weather.. I'm kind of hoping for a break in the weather Saturday into Sunday so the birds will fly..

[orangeblood]

Looking beyond this weekends system, I'm starting to notice the teleconnection indices coming together for a potential very very cold December setup. As Ntxw pointed out yesterday, the coldest air in the Northern Hemisphere is over North America right now and is forecast to build over the next few weeks. With the AO potentially going in the tank to start December, all of that cold air could be forced even further south into the US and could overwhelm the pattern. Just something to pay attention to going into next month.

[gboudx]

wxman, could you do a GFS meteogram for Austin?

Thanks,
Cameron

I don't think I got the timestamp right, but you can get the idea. Pay no attention to the January date and the IAH. I assure you this is from today for Austin. I forgot to update the title.

[Longhornmaniac8]

We're getting pretty close. It's going to be interesting to see when that low ejects. It seems to be trending sooner rather than later...

Thanks for putting that together!

Cheers,
Cameron

[wxman57]

Good try, gboudx, here's a corrected version for Austin:

[gboudx]

Since we're still technically in Fall, Portastorm asked for discussions to occur on the USA & Carribean Weather forum. Check out the Texas Fall 2013 thread.

viewforum.php?f=24

[joshskeety]

Awesome.. My thoughts were correct.. The NWS agrees that the GFS is having a hard time with timing of the front and the surge which was my thought looking at the TAF's..


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
1201 PM CST THU NOV 21 2013

.AVIATION...
/18Z TAFS/

THE STRONG ARCTIC COLD FRONT WAS BARRELING SOUTH THROUGH THE
PANHANDLE AND WESTERN OKLAHOMA THIS MORNING. MODELS HAVE BEEN
STRUGGLING WITH THE INITIAL SHALLOW SURGE OF THIS FRONT AND WITH
TIMING THE FRONT INTO THE AIRPORTS. NOT ONLY WILL THE FRONTAL
TIMING CONTINUE TO BE A CHALLENGE TODAY...BUT ALSO TIMING THE
IMPROVEMENT OF CIGS AND VSBYS ACROSS THE AREA AND CONVECTIVE
CHANCES ALONG AND IN ADVANCE OF THE COLD FRONT.

Not saying that this is pointing to the 12zNAM at 60h out or anything, but interesting enough the 12zNAM was a tad quicker and cooler with this front.. At least it bodes well for the 18z run of the GFS to conform with the latest data and if the 18z NAM will continue the trent of colder, but more moisture than the GFS.

Been fun to watch so far.. Still thinking that the answer is most likely in-between.. I dont see an all snow event, but I do think there will be some and more ice deeper into the Metroplex than was given.. The trend would suggest so anyhow.. Early guess...