Update:
With this latest wintery event less than 24 hours away, computer models still have not completely latched onto a solution. The GFS is becoming an outlier with its surface track farther east over the Atlantic Ocean (which would yield generally less than 3" of snow across the region). Most other models, like the UKMET, NAM, GGEM, MM5, etc. have come into somewhat better agreement in the last few hours supporting a surface track closer to the coast. I have bumped totals in the immediate metro down a notch given my uncertainty, and the potential for the snow to begin closer towards the Mid Morning.

It is possible areas to our southeast get slammed with isolated 6"+ totals. Areas along the Eastern Shore will remain mainly rain, with some mixing possible Monday night. This will keep precip totals generally below 3".

A WINTER WEATHER ADVISORY IS IN EFFECT UNTIL 7 AM EST SUNDAY MORNING FOR AREAS NORTH AND WEST OF THE DISTRICT. THERE IS THE POTENTIAL FOR 1-2 OF SNOW TO ACCUMULATE ACROSS NORTHERN MD AND WV BEFORE EVERYTHING TURNS OVER TO RAIN BY MID MORNING

At publishing time, National Weather Service radar was beginning to pick up echoes over eastern WV and central VA at around 6-7,000 feet off the surface. I have not, however, been able to find any reports of precipitation making it down to the surface as lower levels remain very dry. Dewpoint depressions (simply the difference between the Temperature and Dewpoint, and reveals the relative dryness, or wetness, or the atmosphere) are averaging near 15-25 degrees F, which would indicate an extremely dry surface layer.

Virga and it's relation to the Doughnut Hole:
For this reason, most of the precipitation showing up on the doppler radar is Virga, and is evaporating before it makes it anywhere near the surface. This nifty little schematic reveals how the doppler radar can "sense" falling precip, while nothing is actually hitting the surface. This is also the cause of the famed "doughnut hole" on the radar images often seen before the onset of snow.

Suppose snow is falling through 1000 feet, but evaporating after that. Because the radar beam is tilted (.5 degrees at its minimum), 20-30 miles away from the radar site, the beam will have penetrated the 1kft level. Anything within the 20-30 mile radius will appear to be "high and dry" due to this phenomenon.

Wintry troubles tonight and tomorrow:
Through the next 2-4 hours, snow showers (possibly mixed with some sleet) will begin to overtake the entire region from west to east as a low pressure system develops just west of the Cumberland Plateau. Around the immediate metro, snow showers will rapidly change over to freezing rain/sleet, and eventually pure rain by 4 AM as warmer air noses into the region. Before the changeover occurs, however, there will be a small timeframe in which snow has the potential to accumulate to .5-3 inches across the entire area before rain showers develop by mid morning.

Forecast Confidence: Medium/High

Major Mess Looking Likely Monday and Tuesday:
My basic reasoning from the previous post remains unchanged regarding Monday's system. Computer models have slowed the onset precip time just a tad to around 6-9AM, although this is highly subjective depending on where you live.

I still anticipate a sizeable winter storm flanking the Eastern Seaboard, with most of the precipitation falling in the form of a heavy snow. There are also some indications that would point towards the potential for some thundersnow, which is not all that uncommon with deepening Nor'Easters. Thundersnow can be accompanied by snowfall rates in excess of 4in/hr (although rates closer to 1in/hr look like a stronger possibility).

By the time Tuesday evening rolls around, anywhere from a trace of snow in lower Southern MD, to 4-8 inches in Central MD will be possible. Snow closings may also be in the works, and significant travel delays are a given.

Still, there is a bit of uncertainty revolving around this forecast, but things are coming into much better focus.

The First snowfall Map of the 2005-06 season is issued:
Please bear in mind these are not official forecasts, and should not be treated as such. The following is my preliminary snowfall outlook for our region valid Monday morning through Tuesday evening.

A general swath of 4-8 inches appears to be a good bet around the area, and lesser amounts towards the Eastern Shore, and to our north and west (as you get farther away from the precip shield), although my totals northwest of the area will likely end up being ramped upwards tomorrow.

Forecast Confidence: Medium