Texas winter wx thread (2009-2010)

[msstateguy83]

with what limited data you can get off the ruc i like what iam seeing only goes out 12 hours, but i like what i see it seems to show a faster moving cold front also i think i like the position of the low at about 12 hour out. still a very rapidly changing wx forecast as we get the new 18z gfs data will look over it and compare to the nam but to be blunt about it this thing is still very much up in the air at this hour nothing is locked in for sure.

[Ntxw]

This is only one model difference. I am not saying anything about chances or snow or ice lol simply interpreting what I think the HPC stated. Havoc as in things could change run by run and gives forecasters a handful to make out what will happen.

[txtiff]

This is only one model difference. I am not saying anything about chances or snow or ice lol simply interpreting what I think the HPC stated. Havoc as in things could change run by run and gives forecasters a handful to make out what will happen.

Thanks for that!! and all the info you post!!

[Ntxw]

Hmm I see wxman!!! Wonder what his thoughts are =p

[Weatherdude20]

:uarrow: Alright I'll give this a shot hopefully I'm in the ballpark and not way off. the NAM (a reliable and good resolution model in the short range) has changed direction somewhat in that it wants to create a merge of energy not seen well by the models prior. What could happen (again depicted by this particular model) is a strengthening more compact (powerful) low which will play havoc in forecast. Bottom line, no one really knows for sure.

Are we talking like 1 in 1,000,000?

So you are telling me there is a chance?

Much much much more likely than that.... especially in Denton, where if im not mistaken; you live? =)

[DentonGal]

:uarrow: Alright I'll give this a shot hopefully I'm in the ballpark and not way off. the NAM (a reliable and good resolution model in the short range) has changed direction somewhat in that it wants to create a merge of energy not seen well by the models prior. What could happen (again depicted by this particular model) is a strengthening more compact (powerful) low which will play havoc in forecast. Bottom line, no one really knows for sure.

Are we talking like 1 in 1,000,000?

So you are telling me there is a chance?

Much much much more likely than that.... especially in Denton, where if im not mistaken; you live? =)

I'm in Denton, right at the top of the triangle that connects Dallas-Fort Worth-Denton! Is it looking good for us to get something frozen?

[wxman57]

Just got finished with my meetings for today and started looking at the latest data. From what I see initially, both the GFS and NAM have trended considerably warmer for some areas (like D-FW) in the past few runs. I ran new meteograms for Dallas and thought I was doing something wrong, as neither model forecasts the D-FW area to go below freezing until Friday night. Looking at the model runs themselves (maps with thickness packing and surface isobars), I can see that they're much slower in bringing the cold air south to the D-FW area. All precip falls in significantly warmer air at the surface and aloft. If the trend continues, then the winter precip threat there is reduced, though the models never did show much precip in the cold air in D-FW. I'll take a look at Wichita Falls next.

DFW 12Z GFS Meteogram:


DFW 12Z NAM Meteogram:

[HockeyTx82]

Uh what just happened??????

The forecast just went back to to colder for here........

http://forecast.weather.gov/MapClick.ph ... 2=-97.1309

[wxman57]

Same results for SPS - GFS and NAM are MUCH warmer on Friday, keeping the colder air up in Oklahoma a lot longer. Less post-frontal cold air precip here, too. Talked to my coworker who's been updating forecasts all day and he is tending to believe the warmer temps.

12Z GFS Meteogram for Wichita Falls:


12Z GFS Meteogram for Wichita Falls:

[Portastorm]

I'm confused Wxman57 by your statement that even the 12z NAM came in warmer. There is no doubt (at least in my pea brain) that it is slower with the upper level trough than the 0z run. So ... does that mean slower trough, slower wave development on the front ... slower transport of colder air down south? I need a lesson in synoptics here.

[wxman57]

Uh what just happened??????

The forecast just went back to to colder for here........

http://forecast.weather.gov/MapClick.ph ... 2=-97.1309

Just remember that the data I posted are RAW 2 meter temps. With the last cold outbreak, actual lows were 5-8 deg colder in some areas. Not sure if there will be that much difference between model forecasts and actual lows this time, but the trend upward for temps may be significant. Clearly, the models are keeping the main cold air north of the Red River until the upper trof axis moves across on Friday. That would significantly diminish the winter weather threat in NE Texas.

[Portastorm]

Here's a bummer of a snippet from the afternoon AFD out of NWSFO Austin/San Antonio:

THE RAINS GENERALLY END WITH THE PASSAGE OF THE SQUALL LINE AND
COLD FRONT, HOWEVER, SOME LIGHT RAIN SHOWERS ARE POSSIBLE FRIDAY
MORNING AS THE UPPER TROUGH MOVES ACROSS OUR AREA. THE MODELS
CONTINUE THEIR TREND OF A LESS COLD AIRMASS AND REMOVED MENTION
OF WINTER TYPE PRECIPITATION.

[wxman57]

Here's a bummer of a snippet from the afternoon AFD out of NWSFO Austin/San Antonio:

THE RAINS GENERALLY END WITH THE PASSAGE OF THE SQUALL LINE AND
COLD FRONT, HOWEVER, SOME LIGHT RAIN SHOWERS ARE POSSIBLE FRIDAY
MORNING AS THE UPPER TROUGH MOVES ACROSS OUR AREA. THE MODELS
CONTINUE THEIR TREND OF A LESS COLD AIRMASS AND REMOVED MENTION
OF WINTER TYPE PRECIPITATION.

Based on what I'm seeing, I would expect the DFW office to back off on the winter precip talk for the metroplex.

[msstateguy83]

i could be wrong but i think the models are under not handling the shallowness of the cold air very well at all. hard for me to catch on to the idea of the models saying the front hangs up over central ok tomorrow. doubt it HIGHLY doubt it i would put the front @ the red river by sunrise near dfw by 10-11 am in the morning

EDIT: By 8 Am temps will be i would say 33 in Oklahoma City... 35 in Lawton.. 38 In Ardmore... 37 In Wichita Falls
and will be falling quite rapidly as we go later in the morning..

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

[srainhoutx]

And the 18Z NAM is even slower now with the progression of the system.

[CaptinCrunch]

models are going wack 24hrs out, go figuar And yes NWS DFW has backed off the winter precip to a 30% chance early friday morn, and that is still iffy.

[DentonGal]

sigh....should I start crying now?

[wxman57]

i could be wrong but i think the models are under not handling the shallowness of the cold air very well at all. hard for me to catch on to the idea of the models saying the front hangs up over central ok tomorrow. doubt it HIGHLY doubt it i would put the front @ the red river by sunrise near dfw by 10-11 am in the morning

EDIT: By 8 Am temps will be i would say 33 in Oklahoma City... 35 in Lawton.. 38 In Ardmore... 37 In Wichita Falls
and will be falling quite rapidly as we go later in the morning..

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

The models typically DO have problems with the position of the east-west oriented front ahead of an upper trof. The problem is typically greater with shallower Arctic air, though. But the key to the winter weather location is certainly how far south the cold air is able to sag ahead of the upper trof. Next thing to do is to monitor for model busts. Is the cold air actually moving southward faster than the models? We should know soon.

[sphelps8681]

So how severe will our weather be down here in SE Texas on Friday?

Thanks,

Susan

[Portastorm]

i could be wrong but i think the models are under not handling the shallowness of the cold air very well at all. hard for me to catch on to the idea of the models saying the front hangs up over central ok tomorrow. doubt it HIGHLY doubt it i would put the front @ the red river by sunrise near dfw by 10-11 am in the morning


The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

The thing is ... we're not talking about a classic Arctic outbreak or even a strong polar frontal passage here ... the kind that flow down the leeside of the Rockies and are shallow and overwhelm the pattern. If you look at the current US temps and a color thermal profile, you can see that it's not all that cold right now in Kansas or even Nebraska. The coldest air looks to be headed to our northeast.

I think I get why the warmer temps based on Wxman57's previous post. The colder airmass flowing into the state needs to have the upper trof axis past first to bring down the air. If the trof hangs up further back ... we see less cold air. Right?!