Low pressure tracked up the Mid-Atlantic Coast on the 17th before moving toward New England on the 18th. Precipitation overspread the area on the night of the 17th ahead of the low. Warmer air was drawn into the system, but cold high pressure over New England kept enough low-level cold air in place for a prolonged period of frozen precipitation into the early morning hours of the 18th.

Winter Weather in CALVERT, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Ice accumulation from freezing rain was around two tenths of an inch near Huntingtown.

Winter Weather in ST. MARY'S, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Ice accumulation from freezing rain was around one tenth of an inch near Cuckold Creek.

Winter Weather in CHARLES, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Ice accumulation from freezing rain was around two tenths of an inch near Bryans Road.

Winter Weather in WASHINGTON, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Snowfall averaged between two and three inches across the county.

Winter Weather in HARFORD, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Snowfall totaled up to 1.8 inches at Bel Air. Ice accumulation of fifteen hundredths of an inch was also reported at Bel Air.

Winter Weather in NORTHERN BALTIMORE, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Snowfall totaled up to 1.9 inches about four miles north of Cockeysville.

Winter Weather in FREDERICK, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: CoCoRaHS

Snowfall totaled up to 4.0 inches near Frederick.

Winter Storm in ANNE ARUNDEL, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Public

Ice accumulation from freezing rain was one quarter of an inch at Fort Meade.

Winter Storm in SOUTHERN BALTIMORE, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

A quarter inch of ice was reported due to freezing rain at Dundalk.

Winter Storm in HOWARD, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

A quarter inch of ice was reported due to freezing rain near Ellicott City.

Winter Storm in MONTGOMERY, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

A quarter inch of ice was reported due to freezing rain near Damascus.

Winter Weather in ANNE ARUNDEL, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Snowfall totaled up to less than one half inch across the county. Ice accumulation from freezing rain was around two tenths of an inch near Riva.

Winter Weather in PRINCE GEORGES, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Snowfall totaled up to one half inch at Bowie and ice accumulation from freezing rain averaged between one and two tenths across the county.

Winter Weather in CARROLL, MARYLAND
From 17-JAN-11 20:00:00 to 18-JAN-11 05:00:00 (EST-5)
Reported by: Trained Spotter

Snowfall totaled up to 3.0 inches about four miles northeast of Taneytown. Ice accumulation from freezing rain was around one tenth of an inch near Eldersburg and Westminster.