Christmas Storm V

[NE-Charlotte]

Heres a current look at the players on the field. I have better links, but they take up to much space. You can tell just by looking at water vapor our southern stream isnt to shabby, but its easy to see that the northern stream is the big boy on the block. You folks want a motion sat view of what a phase looks like then click this 1st link. I think after you watch it, you can see how unpredictabel it is for man or model to forecast these type of synoptic events. This link is the Jan 2000 Carolina Crusher. It also shows you why folks west of Augusta/Charlotte/RDU are best served with a phase to originate in the GOM as opposed to The NEcorner of Florida, Jacksonville. There is also a image of what the ETA(Current Nam) displayed right up to the event and what actually took place. The model showed a phased solution happening way later and futher east, than what actually occured.

radar loop from 00Z January 24 (700 PM January 23) through 11Z January 26 (600 AM January 26)

Model Error

In general, forecast models preformed very poorly during this event. An example of this is shown in the image below which compares the 48 hour, observed liquid equivalent precipitation with the Eta model 48 hour forecast valid at the same time (click on the image to enlarge, image provided by Michael Brennan, NC State University). The model failed to capture the significant precipitation over the Carolinas and Virginia; in fact the Eta forecast had no precipitation over Raleigh and Richmond where over an inch of liquid equivalent was observed.

</IMG>

As forecasters scrambled to adjust forecasts to reflect the unfolding snowstorm, there was little time to analyze the full reason why the forecast had gone bad. In the wake of the storm, many were left wondering how nearly two feet of snow could have fallen in less than 24 hours with very little warning. Was there something that could have been analyzed ahead of time that would have lead to questioning of model precipitation forecasts? Or was there a physical mechanism that was misunderstood, or missed by the models? Below is a brief summary of some of the forecast errors and research topics that arose from this case.

Current View of our system: Hopefully the above info gives newbies and others an insight as to how precise things have to be in order to get a phased winter storm to work out just right.

GREAT POST!!. Helps me keep in mind that the models aren't God and anything can and most likely will happen . It could turn good for us snowlovers and could just as easily turn bad for us. Either way I'm not going to pay too much attention to the models right now.

[HWY316wx]

We definitely don't have a perfect system but we're doing our best. I am trying to weed out the worst offenders though.

You are doing great! Keep tazing them!

[SnowNiner]

I'm not willing to believe the models will totally wiff on this like back in 2000. I think at some point they're going to all say the same thing. Trying to figure it out is suspenseful! But depending on the "perfect phase" for us to get a good storm seems to be a reach. The 12Z I think will tell the tale of the trend. If the EURO and GFS are again east I think we're done here IMHO. Again, just from past experience in the metro area, we need moisture when the LOW is to our west. It gets to Florida, we're done with the event unless it's a monster like 2004.

Speaking of it was 2004 a "perfect phase"? How'd we get so much snow in that set up?

[snowlover91]

Everyone might want to take a look at the RUC for the short range. I've used it time and time again and it's been by far the best tool inside of 24 hours. Look at it's 18 hour 500mb map, much stronger than the NAM or GFS with it.

[blam49er]

Heres a current look at the players on the field. I have better links, but they take up to much space. You can tell just by looking at water vapor our southern stream isnt to shabby, but its easy to see that the northern stream is the big boy on the block. You folks want a motion sat view of what a phase looks like then click this 1st link. I think after you watch it, you can see how unpredictabel it is for man or model to forecast these type of synoptic events. This link is the Jan 2000 Carolina Crusher. It also shows you why folks west of Augusta/Charlotte/RDU are best served with a phase to originate in the GOM as opposed to The NEcorner of Florida, Jacksonville. There is also a image of what the ETA(Current Nam) displayed right up to the event and what actually took place. The model showed a phased solution happening way later and futher east, than what actually occured.

radar loop from 00Z January 24 (700 PM January 23) through 11Z January 26 (600 AM January 26)

Model Error

In general, forecast models preformed very poorly during this event. An example of this is shown in the image below which compares the 48 hour, observed liquid equivalent precipitation with the Eta model 48 hour forecast valid at the same time (click on the image to enlarge, image provided by Michael Brennan, NC State University). The model failed to capture the significant precipitation over the Carolinas and Virginia; in fact the Eta forecast had no precipitation over Raleigh and Richmond where over an inch of liquid equivalent was observed.

</IMG>

As forecasters scrambled to adjust forecasts to reflect the unfolding snowstorm, there was little time to analyze the full reason why the forecast had gone bad. In the wake of the storm, many were left wondering how nearly two feet of snow could have fallen in less than 24 hours with very little warning. Was there something that could have been analyzed ahead of time that would have lead to questioning of model precipitation forecasts? Or was there a physical mechanism that was misunderstood, or missed by the models? Below is a brief summary of some of the forecast errors and research topics that arose from this case.

Current View of our system: Hopefully the above info gives newbies and others an insight as to how precise things have to be in order to get a phased winter storm to work out just right.

Thanks for posting this!! As a newbie who reads often and post rarely this really helps me realize how unpredictable the final outcome will be no matter what the models say. Here is hoping for the best for all us snow lovers. Merry Christmas to all!!

[RaleighWx]

My morning update prior to the big 12z runs!

http://www.examiner.com/weather-in-raleigh/snow-potential-remains-however-chances-of-an-extreme-event-look-less-today

[WidreMann]

And the NMM isn't half bad either. It actually has something of a surface low at 48 down in the gulf.

[Brick Tamland]

Yeah, I have zero confidence in the NAM. 12z GFS will indeed be interesting....curious if it can keep stepping a bit westward.

This makes things seem a little better. It looks like the NAM is the most inconsistent of the models now. The Euro still showing the best storm, and the other models have mostly trended toward the Euro, not away from it. So, there is still hope. This model watching can drive you crazy, though.

[snowlover91]

And the NMM isn't half bad either. It actually has something of a surface low at 48 down in the gulf.

Look at the ARW, it's much different from the NMM/Nam solution. The 12z runs of these high resolution models will be important. Generally inside 48 hours I find that using a blend of the ARW/GFS/RUC and looking at the spc meso page is the best thing to do. I would expect qpf in this event to not be handled well also. Could be much drier or wetter than progged.

[burgertime]

12z looking the same as 6z GFS @ 21

[Brick Tamland]

GREAT POST!!. Helps me keep in mind that the models aren't God and anything can and most likely will happen . It could turn good for us snowlovers and could just as easily turn bad for us. Either way I'm not going to pay too much attention to the models right now.

NCSnow's post about the Jan 2000 storm is fantastic. Just shows you that anything can really happen when it comes to snow around here. The models can do their thing, but with situations like this, you never really know what might happen.

[bigdog_10_2002]

For me, the 06z GFS ensemble mean is a nice Christmas snow. I'd take 4-6" in a heartbeat.

Good point. I think many of us get so caught up in catching a "big storm" that we tend to look past the fact that a 2-6" snow is still a great event in the south (much less on Christmas day and in a La Nina pattern)

I'm encouraged that we are getting close to this event and all the players for the big storm are still on the table, however if they don't pan out, the potential is also still strong that we do see some of the white stuff during a time of year that most of us have never seen it.

[strongwxnc]

Looks stronger at 30

12z looking the same as 6z GFS @ 21

[burgertime]

I think this 12z run might be good for us, but hard to tell at this point, it's out to 33 and looking similar to the 6z run.

[burgertime]

Looks stronger at 30

Yep this one might have a better phase.

[Weather Czar]

12z rgem

[burgertime]

@36 our low is just hair north.

[FoothillsNC]

The GFS at 36 looks very healthy on the southern stream and its still closed. The northern stream is diving down but I dont know ifs its coming in far enough west to interact properly with the Texas system. Its a close call with potential though.

[NCStateMMY]

One thing we all need to remember is this: The Euro has been the extreme solution the whole time. In ONE run it has backed off the snowpocalypse solution. This is more than likely going to be what happens, no big, historic, 1'+ event. That is ok. The other models sans the latest NAM have at least been trending in the Euros direction. A widespread 2-4" event with isolated 6"+ pockets is honestly the best the SE can hope for this time of year. I guess I am naive, but I will be thankful to at least see the possibility of snow on Christmas Day. As long as the ground turns white, I will be happy. Let's just be thankful for what we could get. We are going to see snow, may not be the January 2000, February 2004, or March 1980 that we are hoping for, but it is still something. I am still holding out hope something big will happen, but I know whatever we get, I will still enjoy. You all should do the same.

[strongwxnc]

pops a 850 L at 30 a tad bit N of the 06 gfs

Yep this one might have a better phase.

[strongwxnc]

Current surface..

[burgertime]

@42 it's just a tad faster and slightly east of the 6z run, this could make all the difference lets see where she goes from here.

[strongwxnc]

Strong sw continues to be a tad N of the 06 gfs and a little stronger. Not nearly as much NS interactions as the 06gfs....imo

[burgertime]

Strong sw continues to be a tad N of the 06 gfs and a little stronger. Not nearly as much NS interactions as the 06gfs....imo

Yep this one is going to really thread the needle.

[MillzPirate]

The 6z gfs really screwed eastern nc so I hope it looks nothing like that

[burgertime]

Low looks better @48 IMHO we might have something good here.

[burgertime]

NAM and GFS are night and day right now.

[bingcrosbyb]

GFS could phase west. First run I can remember where the southern stream wasn't being pounded into oblivion.

[WXinCanton]

Big differences GFS vs NAM

[strongwxnc]

Looks like a pos tilt at 48 ? little slower ?

NAM and GFS are night and day right now.