December 19 Snow Anniversary Frigid Morning Temps And Light Snow Or Rain Showers Sunday

December 19 2020

Happy Anniversary! Today is the day we had our first of three blizzards in the winter of 2009-2010. With a final official report of 17″ at BWI, that was the biggest December snow  day for the city. The two day storm total was 21.1″ ranking 9th largest for the area. Most of our region was within a few inches of 20 north and west of the Chesapeake Bay.

This morning Baltimore dropped to 22ºF. That was the coldest since last February 15th when it was 19ºF. However, there were widespread teens on the map and that pales in comparison to the Tundra of the Mid Atlantic region.

York, PA was down to 1ºF. That is accurate. This location has been explored for extreme cold over many years. The location of the airport is west of the city is in a bowl, where cold, dense air can drain down the nearby hills and tank the thermometer.

 

 

Baltimore Climate Data Today

Normal Low 27ºF

Record Low 6ºF in 1989

Normal High 44ºF

Record High 66ºF in 1931

Record Snow: 17″ in 2009. * This was originally measured higher, which would have made that the snowiest December  on record. It was later lowered by NWS. But it still ranks as the top December storm and

Morning Set Up

The next weather system is a cold front that will arrive on Sunday. This will actually help to lift the jet stream and let us warm up a little for the first part of Christmas week.  That is, before the arctic front, rain to snow, and flash freeze Christmas Eve night.

 

The trajectory is on a path where a lot of moisture can split around the mountains. This has BUST all over it, but we need to still account for the chance of light presentation as it will be spread across the region.

Afternoon Temperatures 

 

Sunday Weather

 

Will You See Snow Or Rain Showers?

At this point, I would give it a 50% chance across central Maryland in the morning. However, the chances increase in southern PA and western Maryland. Also, rain may mix with snow showers on Delmarva in the afternoon- but not stickage is expected there.

 

GFS Model- Most aggressive 

 

 

ECMWF Model –

This shows that band of light snow farther north at the same time of morning. This is a more common result of this set up, bringing the flakes between Taneytown and York PA, but missing metro Baltimore.

 

NAM 3 Km Model

This model shows that split I was referring to rather well.

 

Here is the afternoon set up with the front across Delmarva. Again, no stickage, but this may end with flakes inland from Easton and north of Salisbury.

 

Christmas Weather:

Last night I wrote about an arctic cold front arriving on Christmas Eve Night.  It is OK to get excited for possible snow, but I think it would be better served to focus on the likely flash freeze that will impact more of the region on Christmas Morning.

 

Click these maps to see that full report.