Snow and Ice Map Posted for Winter Storm

Warm Air Intrusion Looks to Win Out 

Unfortunately the forecast models continue to track Sunday’s storm system inland during the evening hours which will allow for warmer air at 850mb (the mid-levels of the atmosphere) to be pulled westward off of the Atlantic on top of the cold air at the surface. This sets up a scenario where heavy snow will change over to sleet and freezing rain with ice accumulations causing extremely treacherous travel across the Mid-Atlantic as well as the potential for power outages.

Heavy Snow Develops Sunday Afternoon

Snow should develop areawide on Sunday between 4 and 6PM becoming heavy for several hours before a change over to sleet and freezing rain between 8 and 10pm. A snow thump of a few inches are likely before the change over to a wintry mix.  Confidence remains low on exactly when the transition will take place and how soon locations west of interstate 95 change over to rain (cold air at the surfaces may prove more stubborn causing an increased threat of an ice storm across the western and northern suburbs of DC).

 European Model Holds Steady

The heaviest precipitation should begin to taper off after midnight on Monday (Sunday night) with some wrap around snow showers likely on the back side of the storm system. Winds will become gusty during the storm with scattered power outages likely due to the ice accumulations on top of the snow.

Snowfall Accumulation Potential 

Below is how much snow I think will fall across the Greater Washington DC Region

Potential Ice Accretion from Freezing Rain

I remain concerned about locations along the interstate 81 corridor where a quarter of an inch of ice is possible before the system pulls away.  If sleet were to become the predominant precipitation type, then the risk of power outages would decline. Remember sleet is frozen rain drops that bounce when they fall, freezing rain is the liquid that falls as rain and then freezes as glare ice on all untreated surfaces.

Please refrain from traveling Sunday afternoon/evening across the Mid-Atlantic interstates as conditions will deteriorate rapidly.

Also please note this is an extremely tricky forecast as forecast models always try to scour out cold air at the surface too soon.  If freezing rain holds on long across the DC Metro, we may be looking at more of an Ice Storm with power outages due to the gusty winds.

Now is the time to prepare for possible power outages and stock up on items in case you were to lose your power. 



Big Changes in 48 Hours! Rain, Wind and Potential for Snow

Much Needed Rain

The best chance for substantial rain will arrive late tonight with periods of rain continuing through Sunday. A widespread quarter to one half inch of rain is likely.

Sunday Evening

A strong cold front will bring the threat of damaging winds during the evening and overnight hours on Sunday. As temperatures drop rain may mix with and change over to some light snow

Let’s Talk Snow

Will we see our first flakes of the season Sunday evening through Monday morning? If so, how much?

The good news for snow lovers is that the GFS and Canadian are trending toward a snowier solution on Sunday night. However, the European model doesn’t agree… yet.

The bad news is that even if a period of snow develops Sunday evening, the ground is so warm from the recent mild conditions that it wouldn’t stick to much except for grassy surfaces and cars.

I’d like to see tonight’s run of the European model before I attempt to even get my hopes up.