The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or 
CBS local affiliate guy said 30% chance of sleet/snow.
NBC local affiliate guy said 10% chance of sleet/snow.
FOX local affiliate guy said 20% chance of sleet/snow.
All said the chance for snow would last between Dec 24 Noon and end sometime mid-day Dec 25.
I've been making some observations of my own however, and I am an amateur.
Visual Observations (Current time: 1:55am central time):
I just went outside and saw pink colored clouds everywhere passing past the moon every few seconds, a moon which has a beautiful ring around it by the way. It's definately mostly cloudy out there, and quite windy.
Instrument readings (Same time for the current readings):
The dew point is 29 F, the Temperature is 33.6 F, the Relativite Humidity is 82%. The Humidity is falling slightly at about a point every 30 minutes that I have noticed over the last couple hours. I suspect it will get to below freezing in the next hour or 2 at the rate it has been falling. Barometer is 30.22" and steady and has been for last 4 hours flucuating between 30.23" and 30.21".
Temps usually keep falling until 7am-8am here when they start to rise. I know clouds slow the falling of the temps, but over the last 2 hours the temp has started to fall 0.06 degrees per hour, whereas over the hours preceeding that it was falling only 0.03 degrees per hour for 4 straight hours. That's falling at a rate 2x as fast as it was.
The winds are gusting between 10 and 20mph out of the N-NE for the past 10 hours now. Although before that they were blowing 20-30mph.
FYI, The readings are accurate, I am using a Davis Vantage Pro weather station which is a fairly expensive amateur weather station.
Satelite/Radar Observations:
First, Galveston Composite radar loop which shows definite precip over the gulf heading E-NE and it's pretty far north, further north than I thought it was supposed to be according to GFS and ETA models, here is a link: http://www.srh.noaa.gov/radar/loop/DS.p20-r/si.kbro.shtml
Water Vapor Imagery from NE Pacific:
http://www.ssd.noaa.gov/PS/TROP/DATA/RT/nepac-wv-loop.html
The above NE pacific loop shows a lot of moisture streaming E-NE across Mexico, Texas and right towards Lousiana and a good bit of it, I'd say even the brunt of it is passing right over SE LA. This is associated with moisture in the higher layers of the atmosphere as I understand it, not at the surface. But some of it is making it to the surface, as shown in the next observation.
http://www.theneworleanschannel.com/wxmap/811642/detail.html
Look closely, cause it's hard to see, this is a regional radar which is particularly good at filtering out ground clutter. It shows wintery precip as little dots showing up and disappearing over SW LA (Near Lake Charles and also by Lafayette), Between AL/MS border near the coast inland about 50 miles, North of Lake Ponchatrain in the eastern parishes (3 blue dots), and even 2 pink dots south of lake ponchatrain just east of new orleans, in West Central LA but closer to the coast than the north border of the state, and finally South and East of Houston TX. These observations may not be seen when whomever reads this post and replies checks the radar since it is constantly updating, but they were observed by me at 1:55am central time so take my word. Again, just wintery precip indicated dots that lasted 10 min update and disappeared, small little dots nothing more. Maybe they are hitting the ground perhaps they are not. But, I saw one of these dots on the same regional radar near Baton Rouge earlier tonight (as in 12/23 before midnight), and sure enough, there was a noted observation by NWS of snow flurries in Baton Rouge that coincided with that time. So I think it's quite plausible that these areas actually received frozen precip. These observations were taken by the radar between 1:00am and 1:50am (again central time) according to the radar loop which updates every 10 minutes as indicated earlier. All these areas coincide with where this Water Vapor is shown flowing through in the NE pacific WV loop above, and also seen here better in the GOM WV loop:
http://www.ssd.noaa.gov/PS/TROP/DATA/RT/gmex-wv-loop.html
Both this loop and the last (NE Pacific WV) when I viewed them were showing the hours between 20:15 and 7:15 UTC, and they update once per hour, I believe this is 2:15pm through 1:15am central time (6 hours difference if I am doing the time zone conversion right, correct me if I'm wrong). Just to put things into perspective, so you know when I observed them. Although, during the last 7 hours the pattern hasn't changed much. It's a constant flow of moisture from west of Mexico, across Mexico, across SE and South Central Texas, and into SW LA, South Central LA, SE LA, and through Mississippi, Alabama, and Georgie, from almost to the coast on north. I witnessed this pattern change from bone dry (the tan color for dry air) 24 hours ago, all this dry air shifted east originally covering LA completely, then shifted to MS, then AL, then GA, then to the coast, and now it's off the viewable map section I am supposing completely if it exists at all beyond the map I do not know. Point is, this pattern changed dramatically in the last 24 hours.
Also worth mentioning, over the past 36 hours in Metairie, LA (Just east of New Orleans btw 90.1W, 29.9N about) the temp has gone from 70.4 F to 33.6 now. Quite a huge drop in temp for 36 hours or so.
Lastly, since there is nothing showing up on the local New Orleans Doppler yet at this time, except for a few dots on the regional as noted earlier, this is the Lake Charles radar which shows the following:
http://www.srh.noaa.gov/radar/loop/DS.p38cr/si.klch.shtml
When I observed it, at around 2am Central time, it showed yellow, orange, and red rain due east of Victgoria and Corpus Christi texas and due south of Beaumont, TX and Due South of Lake Charles to S-SE of Lake Charles. The general direction of this is over 1 hr an 20 minute time frame is E-NE. I don't know if the stuff off the coast is ground clutter, or what the orange, red and yellow means. It's on a scale called DBZ and doesn't look like regular precip which is usually starting at light green and going to yellow and oranage for severe. This seems to be starting at severe and going in reverse, could someone explain what this means?
Again, I am trying to describe as best I can what I am seeing at the time I'm viewing at at around 2am central time. This precip or whatever it is appears to be heading towards New Orleans, baton rouge, McComb MS, Slidell, Houma, all those areas are in the path from the looks of it.
Does any of my observations help expert meteorlogists out there determine New Orlean's chances of seeing snow on Christmas Eve or Christmas Morning?
Lastly here is the ETA 06z model that just recently came out:
ETA model says:
+12 hrs
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/eta/06/fp0_012.shtml
+18 hrs
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/eta/06/fp0_018.shtml
+24 hrs
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/eta/06/fp0_024.shtml
+30 hrs
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/eta/06/fp0_030.shtml
+36 hrs
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/eta/06/fp0_036.shtml
All of these show precip over SE LA or very close to us during times when we are very close to or behind the freezing line. Also, it's worth noting that the ETA has been kind of biased to the warm and dry side, in my opinion, but I could be wrong, these things are confusing to read and guage points in the U.S. to test at various times and temps coinciding with precip with the time zone conversions and all, but best I can tell it is predicting warmer and drier than it actually became over the past 48 hours. Please correct me if I'm wrong. I felt it would help if I put links and my personal observations all in one post and ask an expert to evaluate it all and tell me what New Orleans chances really are at snow. If someone would do that, I'd appreciate it. I'm open to enthuisist opinions as well if you know what your talking about.
Hope I wasn't too long, I wanted to be thorough and scientific as possible with my data and observations.
Thanks all! Hoping for a white christmas in New Orleans, never seen one in my life
Last time it snowed here was 1989 in fact.
UPDATE: Just thought I'd note the Humidity is now 82% and no longer falling in fact rose 3% in the last hour. Also the temperature is now 33.2 F, and the dew point is 28 F (Down 1 F) according to my Davis weather station. Time is now 2:55am Central time. Barometer is still 30.22" and steady, wind is now blowing between North now at 10 and 15mph seems to have tapered off a bit over the last hour. Thought this might be significant since it bucked the trend I talked about earlier a bit.
ANOTHER UPDATE: 3:52am Central time - 32.7 F (Fell 0.05 in last 60 mins), Humidity still 82%, Baro Pressure now 30.20" and falling slowly down 0.02" in last 60 minutes. Winds now North to North-North East at 10-15mph. Think the moon has set, at least I no longer see it. Still mostly cloudy, lots of clouds.
Thanks again for any input on this matter, everyone in New Orleans thanks you too! We are all wanting very much to experience a white christmas for the first time in a very, very long time.
-Mike in Metairie, LA (suburb of New Orleans)
