WASHINGTON – Unfortunately, we’re hitting a few bumps in the road before we can get to those 50-degree temps, possibly nearing 60, this weekend.
Those “bumps” meaning that we have a threat for some wintry precipitation coming our way in less than 24 hours. And a freezing rain advisory has been issued for our area late tonight through Friday morning.
High pressure is dominating the region Thursday sitting to the north, so Thursday will remain dry. However, that high will slip off the coast Thursday night bringing in a touch of low-level cold air (“cold air damning” or CAD effect) to the region. Temperatures, with clouds and a light easterly wind, will fall into the low 30s overnight.
While this is happening, a piece of energy over the southern plains will be shooting to the northeast and right into the Mid-Atlantic region.
With cold air at the surface and warm air overriding the cold air in place, some spotty freezing rain is in the forecast for the morning, mainly between the hours of 5 a.m. to 9 a.m. and could impact the morning commute. We have seen this several times already this season and the question always remains: when will the cold air erode and the warm air completely take over?
The longer the cold air lasts at the surface while precip is falling in this situation, the more time for a wintry mix/freezing rain to fall. The quicker the warm air can take over while precip is falling, the sooner it will change to all rain.
It seems that the warm air takeover will happen fairly quickly Friday morning and any precip falling will change to plain rain by the mid-morning hours. The graphic below shows an area of freezing rain still around about 8 a.m.
This graphic shows an area of pink over the D.C. region, which represents freezing rain, about 8 a.m. Friday.
By the time we get to the mid-morning hours 10 a.m., a change to plain spotty rain will fall as warm air dominates the column below.
This graphic shows plain rain falling on the D.C. region about 10 a.m. Friday.
So we are not expecting much in the way of icing accumulation, just a minimal amount of icing (less than 0.10 inches). Just a touch of icing is enough to wreak havoc on traveling so I do expect there will be some problems spots, but not widespread.
By Saturday, the D.C. area is still in the warm sector and temperatures will hover near 60 degrees!
Unfortunately, a cold front will sweep through the region bringing about a 70 percent shot of rain showers through the day on Saturday. Localities in the region could see up to 1 inch of rain accumulation through the day on Saturday.
Just a note: The heaviest rain will fall in the afternoon hours.
Don’t worry though, warm air is here to stay at least through Tuesday. You can enjoy the 50s on Sunday as we rapidly clear to sunny skies and the 50s stick around for Monday and Tuesday as well before more seasonable temperatures (40 degrees) return mid-week.