TWAS THE DAY BEFORE CHRISTMAS

Can you believe it, it's December 24th and Santa rides tonight. Seems like just yesterday I was mowing the lawn. Actually, I was mowing the lawn two days before Thanksgiving, which gives you a pretty good idea how mild our fall was until we flipped the switch to that crazy period of snow and cold to end November.

One thing is for sure the remainder of this week and Saturday too, we remain very much on the mild side with cold and snow a no show for holiday travelers. Despite the fact we will be mild, this is not going to be a bright and shiny holiday period. Already, warm air advection is underway and shallow low level moisture will get trapped under a strong inversion. With just enough lift, saturation is likely to occur in the south Wednesday and work its way north in the form of low clouds and drizzle during the day. The lack of sunshine should hold highs in most areas to the low to mid 40s, perhaps some upper 30s in the north where some patchy snow cover remains.

Wednesday night and Christmas, southeast winds will continue to advect low moisture at the surface while within the inversion aloft, plenty of dry air exists. This looks like a pretty solid set-up for fog to develop, and the stagnant nature of the pattern may make it tough to scour out until late Friday. A few light showers may even develop Christmas night as a weak disturbance ripples east. Already fog advisories have been posted to the southwest and those are likely to be expanded into my area Christmas Eve night into Christmas itself. It is possible that pockets of dense fog could develop at times, impacting visibility and travel to some degree, especially at night. The EURO shows relative humidity just above the surface at 99 percent Christmas, which is virtually certain to produce low clouds, fog, and drizzle.

The thick canopy of clouds, potentially through Saturday, will keep temperatures in check with only a small range from highs to lows. In general, lows will be in the low to mid 30s Wednesday night through Friday night, with highs in the low 40s north to the mid to upper 40s elsewhere. Here's projected highs for Christmas day.

Saturday, a fast moving, but vigorous trough will dig southeast transporting a healthy cold front that clears the area by Sunday morning. While it won't deliver any precipitation, it will send in much colder and drier air, scouring out clouds and bringing sunshine Sunday and Monday. The trade-off will be noticeable colder air. After highs Saturday in the upper 40s to mid 50s, Sunday starts with relatively mild, with temperatures around 30 north to 35 south.

However, brisk NW winds and strong cold air advection will cause temperatures to fall and by evening readings will be in the mid-teens north to mid 20s south.

Wind chills come Sunday evening could be close to zero in the north, with single digit numbers pushing through the south.

After a cold day Monday, it does appear we get a short bounce back next week. However, soon after, the upper level winds amplify into a strong NW flow. We appear to be on the edge of the jet, which means frequent fluctuations in temperatures as fronts regularly come and go. We look like this at 500mb Christmas Eve.

Headed into the New Year, a pretty good buckle and trough is established over the east. We sit in the middle, just close enough to the trough to get occasional shots of cold followed by brief warm-ups. In the end, temperatures may end up close to normal, despite at times being both well above and below.

The GFS meteogram certainly shows the change we are expecting after December 27th.

One period to keep an eye on is December 31st, when the EURO slips a strong Arctic front in from the northwest. It indicates the potential of light snow that is accompanied by very strong winds and a rapid drop in temperature, New Year's Eve. Low confidence on that scenario this far out.

Otherwise, the NW flow will restrict moisture and precipitation should be confined to any fast moving clipper that dives southeast. Overall, below normal precipitation appears a good bet from now until January 6th.

Have a very merry Christmas, and here's hoping the big man brings you something extra special. Roll weather...TS