A cold front will sweep through the region on Monday afternoon/evening. Temperatures will fall behind the front, eventually ending up in the 30s for overnight lows!
- Cold front will move through Monday afternoon/evening bringing a threat of isolated showers and dropping temperatures.
Eventually that front will stall just to the south of the region. An area of low pressure will ride along the front Monday night into Tuesday bringing precip with it. At the same time, high pressure will move front the Great Lakes region to the New England area. Eventually this evening, our winds will shift to the north and east bringing moisture and cooler air off the Atlantic Ocean and right into our area. What happens is, that moisture banks up against the mountains to our west creating a “cold air damming” affect or CAD. This set up generally makes forecasting that much more difficult, especially when determining precipitation types because that colder air will slide right under the warm air aloft which would make the precip type more of that of a wintry mix (freezing rain/sleet).
- Winter Weather Advisory from 1am Tuesday to 1am Wednesday
Just around daybreak and into the morning commute, we will start to experience some spotty sleet and freezing rain, mainly north and west of D.C. (Loudoun County and Central and Western Montgomery County and points northwest). Inside the beltway, along I-95 and areas to the south and east, this event mainly looks like a very cold rain event but I can’t rule out some isolated pockets around D.C. of the wintry mix.
This is NOT looking like a major event but since it comes for the morning rush, there could be some problems (as there tends to be, even if it is just plain rain). And we are really not expecting that much to accumulate at all, perhaps just a glaze in some areas. Surface road temperatures, especially around the D.C. area, are above freezing so just like last Wednesday, any frozen precip that falls will have a hard time sticking. However, north and west of town on some rural roads, elevated surfaces (bridges and overpasses) and even exits could have some slick spots.
- In-house model of Tuesday morning (rain = green, wintry mix = pink)
Again, I do not think this is going to be a huge event but I don’t want it to take anybody by surprise when our temperatures do not make it out of the 30s tomorrow (considering we are around 70 in a lot of the area on Monday).
Warm air will start to erode the shallow layer of cold air and any wintry mix will turn to plain rain by the afternoon hours. Most of the precipitation should move north around the kickoff of the evening commute but I do expect there to be some drizzle and fog around the region – there could even be some freezing drizzle at the high elevations). Temperatures rebound into the lower 50s on Wednesday but another bout of precipitation could be on the horizon for Friday.