The official predictions for tomorrow's snowstorm, continue to get deeper. The National Weather Service is now warning of 5 to 10 inches in the metropolitan areas of Baltimore and Washington. While the precip may mix with rain south of Washington, it looks like all snow here in the Baltimore area. Here is the advisory just issued this morning:

"A WINTER STORM WATCH REMAINS IN EFFECT FROM SATURDAY MORNING
THROUGH LATE SATURDAY NIGHT.

"A STRONG LOW PRESSURE SYSTEM WILL DEVELOP ALONG THE GULF COAST
TODAY...AND MOVE NORTHEAST TO THE MID-ATLANTIC SATURDAY. A BAND
OF MODERATE TO HEAVY SNOW IS LIKELY TO DEVELOP ACROSS THE REGION
SATURDAY AFTERNOON AND SATURDAY NIGHT.

"SNOW MAY MIX WITH RAIN OR
SLEET SATURDAY MORNING THROUGH SATURDAY AFTERNOON SOUTH OF THE
WASHINGTON DC METROPOLITAN AREA...BEFORE COLDER AIR MOVES IN LATE
SATURDAY AFTERNOON AND SATURDAY NIGHT AND TURNS ANY MIXED
PRECIPITATION TO ALL SNOW. AT THIS TIME...A SWATH OF SNOWFALL OF 5
INCHES OR MORE IS LIKELY ACROSS THE AREA...WITH ACCUMULATIONS UP
TO TEN INCHES POSSIBLE.

"NORTHEAST WINDS AT 15 TO 25 MPH SATURDAY WILL SHIFT TO THE NORTH
SATURDAY NIGHT. THE COMBINATION OF MODERATE TO HEAVY SNOW AND WIND
HAS THE POTENTIAL TO REDUCE VISIBILITY TO BELOW ONE HALF OF A MILE.
PLEASE BE PREPARED FOR THE POSSIBILITY OF HAZARDOUS WINTER WEATHER
SATURDAY AND SATURDAY NIGHT. A WINTER STORM WARNING MAY NEED TO BE
ISSUED LATER TODAY OR TONIGHT."

Winter Storm Watches have been posted from Tennessee to Massachusetts, and they include all of Maryland except for the lower Eastern Shore. Here are the definitions for Winter Storm watches and warnings.

AccuWeather has us square in the 6-to-12-inch section of their map. And you can see the storm on their radar, already gaining strength in the lower Mississippi Valley.

It's a classic Nor'easter, with plenty of moisture on tap from the Gulf and the Atlantic, and lots of cold air in place in the Northeast, with more moving in Saturday on stiff north winds. The low intensifies off the coast and ... WHOMP!  We get buried.

And, because this storm looks like it will affect the densely populated cities and urban regions of the Northeast, and may exceed 10 inches in places, it could become the first new storm to be ranked, when it's all over, on the Weather Service's new, five-step Northeast Snowfall Impact Scale.

The system considers snow depth, geographic area affected, and the population living within it. Storms are then scored, and ranked on a five-point scale analogous to the Saffir-Simpson Scale of Hurricane Intensity. The scale includes Categories 1 through 5: Notable, Significant, Major, Crippling and Extreme.

The scale's inventors have already gone back through the archives and identified 70 Northeast storms between 1948 and 2003 that scored high enough to be ranked. The worst were the March 1993 "Superstorm," and the January Blizzard of 1996, both Category 5's. The Presidents' Day Weekend Storm in February 2003 was rated a Category 4 - "Crippling" - for the Northeast. It was Baltimore's worst ever, with 28 inches falling over four days.