Boy everything I'm looking at late this evening I can't see any reason to change the basic forecast.  Yes the NWS to be on the safe side has extended the Winter Weather Advisory into Frederick County Maryland  Yes some of the high spots of Frederick County Maryland may see 1" of snow but this is fine tuning.  Meanwhile, hard to believe after today in the mid-50s, but there will be spots 30-40 miles north and west of DC that will be snow covered by this time Tuesday.  A cold front is near us now and a weak storm or low pressure is bring rain into West Virginia.  Some chilly rain is now likely to spread into the northern and western suburbs by the morning rush hour.  As the storm moves off later tomorrow, even around the DC area the rain will mix with some wet snowflakes.  The road temperatures are in the 50s, so no slippery going or any accumulation here, but across the high spots of northern and western Maryland, several inches of snow possible.  Our latest rain-snow map still consistent from earlier today.  

 But watch for my update tonight ABC7 News at 11 : >)