Colder pattern developing for the second half of December.

Things certainly are changing in the atmosphere from a warm and dry pattern to more of a cold and wet pattern in the southeastern U.S. As I’ve been talking about for a while the pattern seems to be flipping back to a more winter like one for the end of this month. While I certainly can’t tell for sure is if we will see snow anytime soon the pattern is looking favorable for many chances. The first being next week followed by a couple more storm before Christmas.

Next weeks storm:

ecmwf_apcp_f174_usgfs_op_apcp_f156_us

gfs_pr3_slp_t850_east_55gfs_pr3_slp_t850_east_63

The good news in all of this is we might finally be getting some much-needed rainfall. While there is a slight chance of snow next week it looks mainly confined to the mountains.The storm track also becomes much more active as the cold air settle south. The southern storm track from the Gulf of Mexico into the northeast become out dominate track from now until the first of the year. So expect many more storms over the next 2-3weeks.

 

What about the cold air?:

Pretty much all of the short-range climate models shows this “flip” back to cold. These images are 10 chuck of temperature anomalies from the model output. So what you are looking at is the departure from normal temperatures. The color key is on the right.

cfs_anom_t2m_conus_2012121112_x81cfs_anom_t2m_conus_2012121112_x101

cfs_anom_t2m_conus_2012121112_x121cfs_anom_t2m_conus_2012121112_x141

Notice all of these 10 day chucks shows below average temperatures from a large chunks of the southeast. In some cases the departure is between 5-10 degree below the average.

 

What about snow?

Well as always this is a lot harder but just for fun here the CFS climate models snow depth forecast. Remember these 4 panels are 4 runs or ensembles of the model for the 10 day period from Dec 21-Dec 31. Which does include Christmas. So what the model is trying to snow is the maximum snow that might occur at some point in this time frame. Just for fun so take this an ides and not a forecast. Smile

cfs_snow_max_conus_2012121112_x81