White Christmas for 50% of the US?

[Lou Ruh]

Of course, it did snow in both cities on Christmas but after the 12Z time of the map.

Actually, I believe it snowed in the NYC area only on 12/26. Reporting stations in the DC area and the Philadelphia area showed a trace of snow on 12/25 but the bulk of the snow fell on 12/26. I don't think there was any snow on the ground in any of the major cities from DC to NYC on 12/25. I know I didn't see any snow as I was driving home on 12/26 from Central PA to SE PA until well into the afternoon.

The storm was really a "Boxing Day" storm as opposed to a Christmas Day storm. You can check the reports at http://www.weather.gov/climate/index.php?wfo=okx , http://www.weather.gov/climate/index.php?wfo=lwx and http://www.weather.gov/climate/index.php?wfo=phi for the "official" (well they are still officially preliminary but probably pretty close) reports (which are all in EST or local time).

 

[jshields]

As a member of the AccuWeather team, I wish to point out that Joe's forecast was excellent.

i do seem to remember a certain snowstorm that was supposed to hit the east coast around the middle of the month, that never materialized. they talked about it for weeks in advance and that example is what i was referring to. it seems like sometimes they try to predict some big event 10-14 days out, when we all know models are generally not very accurate that far out. but that wasn't their fault, the models were all showing that for some time! i think at one point they were also talking about storm after storm that was supposed to lineup burying everyone in snow. generally that didn't happen either. however, they do a great job of forecasting(for the east coast) lol! sorry mike, i didn't mean to step on any toes!

the map did show omaha had a white christmas but according to the nws here they officially put down omaha didn't have a white christmas.
"HOWEVER...OMAHA OFFICIALLY
DID NOT HAVE A WHITE CHRISTMAS...AS THE SNOW SETTLED ENOUGH BY
CHRISTMAS MORNING TO LEAVE ONLY A TRACE OF SNOW DEPTH ON THE
GROUND."

 

[Chris Carter]

i do seem to remember a certain snowstorm that was supposed to hit the east coast around the middle of the month, that never materialized. they talked about it for weeks in advance and that example is what i was referring to. it seems like sometimes they try to predict some big event 10-14 days out, when we all know models are generally not very accurate that far out. but that wasn't their fault, the models were all showing that for some time! i think at one point they were also talking about storm after storm that was supposed to lineup burying everyone in snow. generally that didn't happen either. however, they do a great job of forecasting(for the east coast) lol! sorry mike, i didn't mean to step on any toes!

the map did show omaha had a white christmas but according to the nws here they officially put down omaha didn't have a white christmas.
"HOWEVER...OMAHA OFFICIALLY
DID NOT HAVE A WHITE CHRISTMAS...AS THE SNOW SETTLED ENOUGH BY
CHRISTMAS MORNING TO LEAVE ONLY A TRACE OF SNOW DEPTH ON THE
GROUND."

I don't know where i read it, but i thought the proper measurement for a white christmas from a meteorological standpoint is that there has to 1" or greater snowpack on the ground to qualify by 2359Z on Christmas Day. Omaha did not have that because everyone in the metro was under 1". It did look pretty, but not a white christmas.

 

[Patrick Marsh]

The map presented above is actually the snow cover for 24 December 2010. It was generated on 25 December 2010 at 6 UTC, which is 1 AM EST. Thus, all the snow that fell on the 25th is not accounted for in the above graphic.

You can see the correct snow cover map and where snow fell on the 25th here: http://www.patricktmarsh.com/2010/12/day-360-white-christmases-a-noreaster/

I should point out that I believe 52% of the country had snow cover on the 25th.

 

[John Farley]

Thanks, Patrick, my bad on the other map which was a bit early. Quite a bit did fall on Christmas day from northern AL up through western and southern VA. Still none in NYC, though. I was in the Hartford, CT area and can report there was definitely no snow there on Christmas, although that changed drastically all over the northeast the next couple days.

I didn't check, but am thinking the map that was posted for last year may have the same issue as the one I posted, as I recall some snow falling in the STL area on Christmas day last year.

 

[Lou Ruh]

You can see the correct snow cover map and where snow fell on the 25th here: http://www.patricktmarsh.com/2010/12/day-360-white-christmases-a-noreaster/

I should point out that I believe 52% of the country had snow cover on the 25th.

From my personal experience (I was in North Central PA for Christmas and drove across I80 and down I476 to SE PA on 12/26 in the morning), I think the maps overdo the snow cover for that portion of PA. I saw very little snow on the ground and only widely scattered flurries for those areas during that period. How were these maps generated?

 

[Patrick Marsh]

These are model generated. Keep in mind that the color scale starts at very low numbers (less than 1 cm [0.39 inches]) so it's possible that areas that are shaded had very few patches of snow on the ground. (Just a possibility.)