Low pressure moved from the Ohio Valley on the 20th to the Mid-Atlantic region on the 21st.  East winds ahead of the system ushered moist air into the region directly from the Atlantic Ocean.  When the low passed through on the morning and afternoon of the 21st heavy rain fell east of the Blue Ridge Mountains.  Temperatures were cold enough in Allegany County that most of the precipitation fell in the form of snow.  Frostburg reported 6 inches of accumulation.  Rainfall amounts in Washington County included 2.67 inches in Smithsburg, 2.43 inches in Hagerstown, 2.31 inches in Sharpsburg, 1.90 inches in Williamsport, and 1.80 inches in Hancock.  The deluge of rain caused Beaver Creek to overflow onto Route 66 and Conococheague Creek to flood Wishard Road as it rose a half foot above flood stage.  In Frederick County, rainfall totals included 3.30 inches in Thurmont, 2.55 inches in Emmitsburg, 2.10 inches in Wolfsville, and 2.05 inches in Frederick.  Carroll Creek overflowed onto Gas House Pike and Israel Creek flooded Route 26.  The Monocacy River near Frederick rose to 16.4 feet, nearly 1.5 feet above flood stage, on the 22nd causing flood waters to affect the sewage treatment plant. In Carroll County, rainfall amounts included 2.57 inches in Finksburg, 2.52 inches in Sykesville, 2.41 inches in Millers, 2.37 inches in Manchester, 2.28 inches at Piney Run, and 2.25 inches in Westminister.  In Baltimore County, rainfall amounts included 3.16 inches in Pikesville, 2.77 inches in Owings Mills, 2.60 inches in Fullerton and Freeland, 2.31 inches in Parkton, 2.24 inches in Perry Hall, 2.16 inches in Cedermere, 2.04 inches in Freeland and Westview, 1.91 inches at the Maryland Science Center, 1.88 inches in Carroll Park, and 1.84 inches at Jones Falls.  In Harford County, rainfall totals included 4.41 inches in Aberdeen, 3.95 inches at Conwingo Dam, and 2.55 inches in Bel Air. Little North East Creek, North Creek, and Swan Creek overflowed their banks.  Rainfall totals for Howard and Montgomery Counties included 3.00 inches in Cooksville, 2.59 inches in Laurel, 2.52 inches in Gaithersburg, 2.46 inches in Waterloo and Olney, 2.44 inches in Lisbon, 2.40 inches in Washington Grove, 2.31 inches in Forest Glen, 2.30 inches in Potomac, 2.29 inches in Ellicott City, 2.00 inches in Elkridge, and 1.93 inches in Rockville. Rainfall amounts in Anne Arundel County included 3.69 inches in Annapolis, 3.00 inches at the Naval Academy, 2.26 inches in Lothian, 2.13 inches at Baltimore/Washington International Airport, 1.86 inches in Davidsonville, and 1.71 inches in Millersville.  Heavy rain saturated soil to the point that trees were felled. Downed trees were reported on Generals Highway, Saltzmann Road, across the community of Cypress Creek, and on the campus of St. John's College.  Flood waters closed parts of Patuxent Road, Brock Bridge Road, Ridge Road, Old Mill Road, and Governor's Bridge Road.  Flooded roadways were also reported in Glen Isle, Avalon Shores, Franklin Manor, Shady Side, and Triton Beach.  Rainfall totals in Prince George's County included 3.36 inches in Mitchellville, 3.12 inches at Brown Landfill, 2.96 inches in Bowie and District Heights, 2.88 inches in Greenbelt, 2.55 inches in South Bowie, 2.48 inches at Andrews Air Force Base, and 2.36 inches in Oxon Hill.  Rainfall reports across Calvert, Charles, and St. Mary's Counties included 2.06 inches in Bryans Road, 2.04 inches in Ridge, 2.00 inches in Waldorf, and 1.36 inches in Tall Timbers.

Heavy Rain in CHARLES, MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC

Heavy Rain in ST. MARY'S, MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC

Winter Storm in ALLEGANY, MARYLAND
From 21-MAR-00 00:00:00 to 21-MAR-00 12:00:00 (EST)
Reported by: TRAINED SPOTTER

Flood in WASHINGTON, MARYLAND
From 22-MAR-00 02:00:00 to 22-MAR-00 18:15:00 (EST)
Reported by: OFFICIAL NWS OBS.

Flood in FREDERICK, MARYLAND
From 22-MAR-00 08:45:00 to 22-MAR-00 22:45:00 (EST)
Reported by: OFFICIAL NWS OBS.

Flash Flood in ANNE ARUNDEL, MARYLAND
From 21-MAR-00 17:00:00 to 21-MAR-00 23:59:00 (EST)
Location: COUNTYWIDE
Reported by: EMERGENCY MANAGER

Flash Flood in HARFORD, MARYLAND
From 21-MAR-00 17:30:00 to 21-MAR-00 23:59:00 (EST)
Location: COUNTYWIDE
Reported by: TRAINED SPOTTER

Flash Flood in WASHINGTON, MARYLAND
From 21-MAR-00 09:00:00 to 21-MAR-00 12:00:00 (EST)
Location: COUNTYWIDE
Reported by: TRAINED SPOTTER

Flash Flood in FREDERICK, MARYLAND
From 21-MAR-00 09:00:00 to 21-MAR-00 13:00:00 (EST)
Location: COUNTYWIDE
Reported by: NEWSPAPER

Heavy Rain in CARROLL, MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC

Heavy Rain in BALTIMORE, MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC

Heavy Rain in BALTIMORE CITY (C), MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC

Heavy Rain in MONTGOMERY, MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC

Heavy Rain in HOWARD, MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC

Heavy Rain in PRINCE GEORGE'S, MARYLAND
From 21-MAR-00 08:00:00 to 21-MAR-00 16:00:00 (EST)
Location: COUNTYWIDE
Reported by: AWOS,ASOS,MESONET,ETC