WOW. 12Z GFS Huge snowstorm TX GulfCoast to AL/FL GulfCoast!

[KWT]

well its does look fairly intresting for some areas of the U.S,I shall keep watch on here to find out what happens.

while also over here in the U.K,I'm also amazed at 12z GFS potenial,certainly boxing day could well see some heavy and widespread snow if things fall into place,however unlike over in the u.s it would really only need one small factor to form and insted of heavy snow it'd be heavy rain,such is the vairablity of the U.K's weather.

(P.s,its nice to see the possiblity of a omega block forming by Chritmas eve.)

[PurdueWx80]

Is anyone picking this up besides the GFS?

None of the other models go out that far, so we'll have nothing to compare it to for another day or so (once the Euro and Canadian 240-hr forecasts are at the same time as the GFS 240-hr). According to that map, most of the precipitation in TX would not be snow, because the precipitation would've fallen before the coldest air crashed in. It's exciting, but not worth worrying about at the moment.

I 100% DISAGREE IF THAT WAS TO VERIFY ABOVE! Not sure where you learned your stuff but you are so very wrong.

I guess my degree in synoptic meteorology and ~2 years of graduate coursework were all a waste of time then - better go demand my money back.

Those are 12-hr precipitation totals from the period beginning 12 hours before the verification time. If you look back to 240 hrs, the 540 thickness is much further north so you would have to extrapolate between there and 252. Some precip would be frozen, but not in the TX Gulf Coast, more likely near DFW, and it would be light. 540 is a VERY general rule that is incorrect more often than not. For snow, 'tis better to look at 1000-850 thicknesses, 850 temps (near -4C) and surface temps (near freezing), and points in between in case there is a strong temperature inversion in there. Those fine details are simply much too difficult to pick out from a crazy model run that is more than 10 days away. I understand the excitement but you have to look at the facts.

[Stormsfury]

Is anyone picking this up besides the GFS?

None of the other models go out that far, so we'll have nothing to compare it to for another day or so (once the Euro and Canadian 240-hr forecasts are at the same time as the GFS 240-hr). According to that map, most of the precipitation in TX would not be snow, because the precipitation would've fallen before the coldest air crashed in. It's exciting, but not worth worrying about at the moment.

Since that GFS plot would likely not verify anyway, but the issue is .. yes, that WOULD be a snow event due to lapse rates caused by dynamical forces. It WOULD start out as rain (very cold), and possible frozen, but the high pressure origin is arctic, and shallow, so the normal thickness schemes may not apply. yes, good assertion to check the 1000-850mb, and 850mb-700mb thickness schemes in that regards ... but Blue Northers typically have SFC temperatures comparable at or even lower than 850mb temperatures in many cases...

SF

[Guest]

Is anyone picking this up besides the GFS?

None of the other models go out that far, so we'll have nothing to compare it to for another day or so (once the Euro and Canadian 240-hr forecasts are at the same time as the GFS 240-hr). According to that map, most of the precipitation in TX would not be snow, because the precipitation would've fallen before the coldest air crashed in. It's exciting, but not worth worrying about at the moment.

I 100% DISAGREE IF THAT WAS TO VERIFY ABOVE! Not sure where you learned your stuff but you are so very wrong.

I guess my degree in synoptic meteorology and ~2 years of graduate coursework were all a waste of time then - better go demand my money back.

Those are 12-hr precipitation totals from the period beginning 12 hours before the verification time. If you look back to 240 hrs, the 540 thickness is much further north so you would have to extrapolate between there and 252. Some precip would be frozen, but not in the TX Gulf Coast, more likely near DFW, and it would be light. 540 is a VERY general rule that is incorrect more often than not. For snow, 'tis better to look at 1000-850 thicknesses, 850 temps (near -4C) and surface temps (near freezing), and points in between in case there is a strong temperature inversion in there. Those fine details are simply much too difficult to pick out from a crazy model run that is more than 10 days away. I understand the excitement but you have to look at the facts.

First off i wasnt arguing for the storm itself. Yeah i do know the Good for sh!t rule with the gfs ESPECIALLY this far out. My argument was your assumption that them maps showed all rain for TX.

[Guest]

Is anyone picking this up besides the GFS?

None of the other models go out that far, so we'll have nothing to compare it to for another day or so (once the Euro and Canadian 240-hr forecasts are at the same time as the GFS 240-hr). According to that map, most of the precipitation in TX would not be snow, because the precipitation would've fallen before the coldest air crashed in. It's exciting, but not worth worrying about at the moment.

Since that GFS plot would likely not verify anyway, but the issue is .. yes, that WOULD be a snow event due to lapse rates caused by dynamical forces. It WOULD start out as rain (very cold), and possible frozen, but the high pressure origin is arctic, and shallow, so the normal thickness schemes may not apply. yes, good assertion to check the 1000-850mb, and 850mb-700mb thickness schemes in that regards ... but Blue Northers typically have SFC temperatures comparable at or even lower than 850mb temperatures in many cases...

SF

Thank you.

[Stormsfury]

The run would indicate a 12 hour period of light snow as 1000mb-500mb thickness crash BLO 534DM w/a very sharp 850mb thermal gradient of 10C for only about 50 NM distance, but looking further into the run w/500mb heights suggest that the SFC depiction to 500mb heights is total bunk anyways ...

SF

[Guest]

The run would indicate a 12 hour period of light snow as 1000mb-500mb thickness crash BLO 534DM w/a very sharp 850mb thermal gradient of 10C for only about 50 NM distance, but looking further into the run w/500mb heights suggest that the SFC depiction to 500mb heights is total bunk anyways ...

SF

The next week or 2 is going to be a real pain in the rear with the set up as already seen the models ALL seem to be having a diffacult time with each of the systems starting with this weekends event and then next weeks.

Gonna be intresting to say the least.

[PurdueWx80]

Is anyone picking this up besides the GFS?

None of the other models go out that far, so we'll have nothing to compare it to for another day or so (once the Euro and Canadian 240-hr forecasts are at the same time as the GFS 240-hr). According to that map, most of the precipitation in TX would not be snow, because the precipitation would've fallen before the coldest air crashed in. It's exciting, but not worth worrying about at the moment.

I 100% DISAGREE IF THAT WAS TO VERIFY ABOVE! Not sure where you learned your stuff but you are so very wrong.

I guess my degree in synoptic meteorology and ~2 years of graduate coursework were all a waste of time then - better go demand my money back.

Those are 12-hr precipitation totals from the period beginning 12 hours before the verification time. If you look back to 240 hrs, the 540 thickness is much further north so you would have to extrapolate between there and 252. Some precip would be frozen, but not in the TX Gulf Coast, more likely near DFW, and it would be light. 540 is a VERY general rule that is incorrect more often than not. For snow, 'tis better to look at 1000-850 thicknesses, 850 temps (near -4C) and surface temps (near freezing), and points in between in case there is a strong temperature inversion in there. Those fine details are simply much too difficult to pick out from a crazy model run that is more than 10 days away. I understand the excitement but you have to look at the facts.

First off i wasnt arguing for the storm itself. Yeah i do know the Good for sh!t rule with the gfs ESPECIALLY this far out. My argument was your assumption that them maps showed all rain for TX.

My argument was about the assumptions of thickness schemes and low-level temperatures, which I still know and believe to be true. Also, the topic of this thread is quite misleading, as none of those maps show snow in the AL/FL Gulf coast region - parts of the south (i.e. Atlanta), yes/maybe, but not the coast, and I still think it's quite iffy for the TX coast, according to that map. Again, I will re-emphasize that all the precip we see falling was the 12 hours prior to the thickness scheme at verification time - things have changed between the two times and it's almost impossible to extrapolate a 12 hour period on fine details like these.

[Stormsfury]

The next week or 2 is going to be a real pain in the rear with the set up as already seen the models ALL seem to be having a diffacult time with each of the systems starting with this weekends event and then next weeks.

Gonna be intresting to say the least.

the complex pattern and structure for the rest of this week and early next week is the real pain in the arse ... afterwards, a broad CONUS wide trough (should the current EC progs hold true, well, things become more interesting in regards to overrunning events with potential for cold air damming ...

0z ECMWF seems to cut off a lot of energy back off the SW states again, but haven't looked hard into the run as of yet ... and the 12z is forthcoming.

SF

[PurdueWx80]

The next week or 2 is going to be a real pain in the rear with the set up as already seen the models ALL seem to be having a diffacult time with each of the systems starting with this weekends event and then next weeks.

Gonna be intresting to say the least.

the complex pattern and structure for the rest of this week and early next week is the real pain in the arse ... afterwards, a broad CONUS wide trough (should the current EC progs hold true, well, things become more interesting in regards to overrunning events with potential for cold air damming ...

0z ECMWF seems to cut off a lot of energy back off the SW states again, but haven't looked hard into the run as of yet ... and the 12z is forthcoming.

SF

The 12Z Euro also cuts off much of the energy in the SW at 168-h with a broad positively-tilted trough in the central US. The streams are completely split according to that scenario. Notice the block trying to go up over Greenland though!! Perhaps it's a sign of things to come.

[PTrackerLA]

Not sure what will happen next week but this weekend could turn out very cold. Accuweather already has us at 24 for lows on Sunday night and Monday and the latest GFS run would suggest colder than that...

[Stormsfury]

The 12Z Euro also cuts off much of the energy in the SW at 168-h with a broad positively-tilted trough in the central US. The streams are completely split according to that scenario. Notice the block trying to go up over Greenland though!! Perhaps it's a sign of things to come.

does appear to be setting up a rex-block type signature in the E PAC. Definitely trending towards Greenland blocking as height rises in response to the PV NNE of Hudson Bay ...

what this would serve to do WRT to the split flow, would lend credence to the potential for Arctic/Canadian Highs to slide down the East (CAD scenarios), w/ any luck (for us out East), the southern stream becomes active for potential of overrunning events.

SF

[Wnghs2007]

The 12Z Euro also cuts off much of the energy in the SW at 168-h with a broad positively-tilted trough in the central US. The streams are completely split according to that scenario. Notice the block trying to go up over Greenland though!! Perhaps it's a sign of things to come.

does appear to be setting up a rex-block type signature in the E PAC. Definitely trending towards Greenland blocking as height rises in response to the PV NNE of Hudson Bay ...

what this would serve to do WRT to the split flow, would lend credence to the potential for Arctic/Canadian Highs to slide down the East (CAD scenarios), w/ any luck (for us out East), the southern stream becomes active for potential of overrunning events.

SF

I love you. To bad you are a man or I would marry you. j/k

[Anonymous]

The 12Z Euro also cuts off much of the energy in the SW at 168-h with a broad positively-tilted trough in the central US. The streams are completely split according to that scenario. Notice the block trying to go up over Greenland though!! Perhaps it's a sign of things to come.

does appear to be setting up a rex-block type signature in the E PAC. Definitely trending towards Greenland blocking as height rises in response to the PV NNE of Hudson Bay ...

what this would serve to do WRT to the split flow, would lend credence to the potential for Arctic/Canadian Highs to slide down the East (CAD scenarios), w/ any luck (for us out East), the southern stream becomes active for potential of overrunning events.

SF

Can you say PDS II redux?

Yeah, I can dream..........

-Jeb

[Anonymous]

HELP!!

Where can I find nomographs for different cities in the CONUS?
Thanks!

-Jeb

[alicia-w]

i have seen snow here before. it just never amounts to anything. melts the second it hits the ground. if it stays cold long enough, that could change.

[Wpwxguy]

Check out James Spanns web video update........Just out for afternoon!
WOW!!! is the word. Everyday is looking better for a southern snow event
.
http://beta.abc3340.com/weather/video.hrb

[CajunMama]

KOW...would this be the snow that someone promised frick & frack last year?

[aggiecutter]

The GFS continues its western retrogression of this weekends trough in its 18z run. The previous 3 runs have done the same. This could have huge implications for Texas temps this weekend, particularly the eastern half of the state.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _090.shtml

[WhiteShirt]

Check out James Spanns web video update........Just out for afternoon!
WOW!!! is the word. Everyday is looking better for a southern snow event
.
http://beta.abc3340.com/weather/video.hrb

I'm on dial-up, and the video won't load. Could you give a summary of it? Snow for the Houston area???? Thanks.