First up is a cold front which will be moving across our area this afternoon. Precipitation associated with the front will begin as some light rain which will increase a bit in intensity as the afternoon becomes the evening. The cold air will take a little while to catch up but eventually it will move across the area from north to south bringing a changeover in the precipitation that's falling from rain to sleet and eventually over to all snow.
At the same time, a low pressure area will move out of the midwest and cross the region bringing the bulk of our precipitation - especially towards midnight and into the early morning hours Tuesday.
This should be a brief storm but it could be a bigger deal than it even looks now. That "banding" effect we've talked about before could lead to locally heavy precipitation amounts and the model trends have been colder and wetter the last few runs.
Waiting for the afternoon models but I think 2 inches is a good possibility in the immediate DC area, more as you go north and west. There is the potential for more - maybe 4 inches or more - but before we go there, I'd like to see what the afternoon models have to say. But, just to put it out there, here's the GFS 24-hour total precipitation forecast:
You can see we're squarely in the .5-.75 liquid precipitation range. Given that we may lose a bit to rainfall and some sleet, this argues for 4 inches or so.
One thing the precipitation will be fighting is the relatively warm ground temperatures that have developed after the past 5 days or so. On the other hand, the precipitation could be quite heavy later tonight.
Stay tuned...
