Station Name: DIFFICULT RUN NEAR GREAT FALLS, VA
Data Source: Water Data - usgc.gov

Elevation Above Sea Level: 184 feet

Nearest Address:
9200 Old Dominion Dr
McLean, VA 22102
Fairfax County

GPS Coordinates: 38.97594346, -77.24581439

Nearby Water Temperatures

Severe Thunderstorm Watch issued July 9 at 2:30PM EDT until July 9 at 10:00PM EDT by NWS Baltimore MD/Washington DC

Effective: Thu July 9, 2026, 2:30 PM
Expires: Thu July 9, 2026, 10:00 PM

THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH 474 IN EFFECT UNTIL 10 PM EDT THIS EVENING FOR THE FOLLOWING AREAS THE DISTRICT OF COLUMBIA IN MARYLAND THIS WATCH INCLUDES 14 COUNTIES IN CENTRAL MARYLAND ANNE ARUNDEL HOWARD MONTGOMERY PRINCE GEORGES IN NORTH CENTRAL MARYLAND CARROLL FREDERICK WASHINGTON IN NORTHEAST MARYLAND CECIL IN NORTHERN MARYLAND BALTIMORE BALTIMORE CITY HARFORD IN SOUTHERN MARYLAND CALVERT CHARLES ST. MARYS IN VIRGINIA THIS WATCH INCLUDES 27 COUNTIES IN CENTRAL VIRGINIA CITY OF FREDERICKSBURG GREENE KING GEORGE ORANGE SPOTSYLVANIA IN NORTHERN VIRGINIA ARLINGTON CITY OF ALEXANDRIA CITY OF FAIRFAX CITY OF FALLS CHURCH CITY OF MANASSAS CITY OF MANASSAS PARK CULPEPER FAIRFAX FAUQUIER LOUDOUN PRINCE WILLIAM STAFFORD IN NORTHWEST VIRGINIA CITY OF WINCHESTER CLARKE FREDERICK MADISON PAGE RAPPAHANNOCK SHENANDOAH WARREN IN WESTERN VIRGINIA CITY OF HARRISONBURG ROCKINGHAM IN WEST VIRGINIA THIS WATCH INCLUDES 3 COUNTIES IN PANHANDLE WEST VIRGINIA BERKELEY JEFFERSON MORGAN THIS INCLUDES THE CITIES OF ABERDEEN, ABINGDON, ADAMS MORGAN, ADEN, AIRLIE, ALBIN, ALEXANDRIA, ALONZAVILLE, ALSOP, ANDORA, ANNANDALE, ANNAPOLIS, APPLETON, ARCO, ARKENDALE, ARLINGTON, ARNOLD, BAKERTON, BALLENGER CREEK, BALLSTON, BALTIMORE, BARCROFT, BARKSDALE, BAY VIEW, BENTONVILLE, BERKELEY SPGS, BERRYVILLE, BERRYVILLE, BETHEL, BETHESDA, BLAKE, BLOOMERY, BOHEMIAS MILLS, BOWIE, BOYDS, BRANTWOOD, BROKENBURG, BROOKFIELD, BROOMES ISLAND, BUCKEYSTOWN, BUCKTON, BURKE, BURR HILL, BYNUM, CALIFORNIA, CALLAWAY, CARDOVA, CATALPA, CATONSVILLE, CEDAR GROVE, CEDARVILLE, CHANTILLY, CHARLES TOWN, CHERRYDALE, CHESAPEAKE BEACH, CHESTER GAP, CLARKSVILLE, CLARY, CLINTON, COLLEGE PARK, COLUMBIA, COMPTON, COUNTRYSIDE, COVE POINT, CULPEPER, DAHLGREN, DALE CITY, DAMERON, DRUM POINT, DULLES INTERNATIONAL AIRPORT, DUNDALK, DUNKIRK, EDGEWOOD, ELDERSBURG, ESSEX, EVERONA, FAIRFAX, FAIRFAX STATION, FAIRVIEW, FALLS CHURCH, FALMOUTH, FELLS POINT, FIVE FORKS, FORDSVILLE, FOUR CORNERS, FREDERICK, FREDERICKSBURG, FRONT ROYAL, GAINESBORO, GAITHERSBURG, GAMBER, GARRISONVILLE, GATEWOOD, GERMANTOWN, GLEEDSVILLE, GLEN BURNIE, GLEN ECHO, GLENDIE, GLENMONT, GREENBELT, HAGERSTOWN, HALFWAY, HAMBURG, HANCOCK, HARFORD FURNACE, HARRISONBURG, HAWKINSTOWN, HICKORY, HISTORIC ELLICOTT CITY, HOWELLSVILLE, INDEPENDENT HILL, KIMBALL, LAHORE, LAKE RIDGE, LANGLEY, LEESBURG, LEXINGTON PARK, LINVILLE, LONG BEACH, LUCKETTS, LURAY, MADISON MILLS, MADISON RUN, MAGNOLIA, MAGNOLIA, MANASSAS, MANASSAS PARK, MARTINSBURG, MASSAPONAX, MCLEAN, MIDDLEWAY, MILLVILLE, MONTCLAIR, MONTPELIER, MOUNT CLIFTON, MOUNT HARMONY, MOUNT JACKSON, NASONS, OAK GROVE, ORANGE, PARK HEIGHTS, PARK MILLS, PARKVILLE, PARTLOW, PAW PAW, PINEY POINT, POST OAK, RANDALLSTOWN, RANSON, RAPIDAN, REAGAN NATIONAL AIRPORT, RESTON, REVA, RIDGE, RIDGEWAY, RILEYVILLE, RIVERCREST, ROLLINS FORK, ROSSLYN, SEVERN, SEVERNA PARK, SHADY GROVE, SHADY GROVE, SHENANDOAH JUNCTION, SHILOH, SILVER SPRING, SIMPSONVILLE, SKYLAND, SMITH CROSSROADS, SOTTERLEY, SOUTH GATE, SPOTSYLVANIA COURT, ST. CHARLES, STERLING PARK, STEVENSBURG, STRASBURG, STRINGTOWN, SUITLAND-SILVER HILL, TANTALLON, TOWSON, TURNBULL, TWYMANS MILL, UNIONVILLE, WALDORF, WARRENTON, WASHINGTON, WESTMINSTER, WIDEWATER, WINCHESTER, WINSTON, WOODBRIDGE, WOODLAWN, WOODSTOCK, AND WOODSTOCK.

Flood Watch issued July 9 at 12:57PM EDT until July 9 at 11:00PM EDT by NWS Baltimore MD/Washington DC

Effective: Thu July 9, 2026, 12:57 PM
Expires: Thu July 9, 2026, 9:00 PM

* WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...The District of Columbia, Maryland, including the following areas, Anne Arundel, Carroll, Cecil, Central and Southeast Howard, Central and Southeast Montgomery, Frederick, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford and Southern Baltimore, and Virginia, including the following areas, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Clarke, Eastern Loudoun, Fairfax, Northern Fauquier, Northern Virginia Blue Ridge, Northwest Prince William, Page, Rappahannock, Shenandoah, Warren and Western Loudoun. * WHEN...Until 11 PM EDT this evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS... - Clusters of strong to severe thunderstorms are likely to push across the region through this evening. With a continued tropical air mass over the area, very heavy rainfall rates are possible in many of these storms. These rates could approach 2 to 3 inches per hour, with higher instantaneous rates possible. This may cause creeks and stream to quickly rise out of their banks along with potential flash flooding in urban areas. The most vulnerable locations would be urbanized areas along I-95 as well as areas which have experienced heavy rainfall in recent days. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information

You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

Flood Watch issued July 9 at 11:23AM EDT until July 9 at 11:00PM EDT by NWS Baltimore MD/Washington DC

Effective: Thu July 9, 2026, 11:23 AM
Expires: Thu July 9, 2026, 7:30 PM

* WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...Portions of DC, including the following , District of Columbia, Maryland, including the following areas, Anne Arundel, Carroll, Cecil, Central and Southeast Howard, Central and Southeast Montgomery, Frederick, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford and Southern Baltimore, and northern Virginia, including the following areas, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Eastern Loudoun, Fairfax, Northwest Prince William and Western Loudoun. * WHEN...Until 11 PM EDT this evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS... - Clusters of strong to severe thunderstorms are likely to push across the region this afternoon and evening. With a continued tropical air mass over the area, very heavy rainfall rates are possible in many of these storms. These rates could approach 2 to 3 inches per hour, with higher instantaneous rates possible. The most vulnerable locations would be urbanized areas along I-95 as well as areas which have experienced heavy rainfall in recent days. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information

You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

Severe Thunderstorm Watch issued July 9 at 5:50PM EDT until July 9 at 10:00PM EDT by NWS Baltimore MD/Washington DC

Effective: Thu July 9, 2026, 5:50 PM
Expires: Thu July 9, 2026, 10:00 PM

SEVERE THUNDERSTORM WATCH 474 REMAINS VALID UNTIL 10 PM EDT THIS EVENING FOR THE FOLLOWING AREAS THE DISTRICT OF COLUMBIA IN MARYLAND THIS WATCH INCLUDES 12 COUNTIES IN CENTRAL MARYLAND ANNE ARUNDEL HOWARD MONTGOMERY PRINCE GEORGES IN NORTH CENTRAL MARYLAND CARROLL IN NORTHEAST MARYLAND CECIL IN NORTHERN MARYLAND BALTIMORE BALTIMORE CITY HARFORD IN SOUTHERN MARYLAND CALVERT CHARLES ST. MARYS IN VIRGINIA THIS WATCH INCLUDES 12 COUNTIES IN CENTRAL VIRGINIA CITY OF FREDERICKSBURG KING GEORGE SPOTSYLVANIA IN NORTHERN VIRGINIA ARLINGTON CITY OF ALEXANDRIA CITY OF FAIRFAX CITY OF FALLS CHURCH CITY OF MANASSAS CITY OF MANASSAS PARK FAIRFAX PRINCE WILLIAM STAFFORD THIS INCLUDES THE CITIES OF ABERDEEN, ABINGDON, ADAMS MORGAN, ADEN, ALEXANDRIA, ALSOP, ANDORA, ANNANDALE, ANNAPOLIS, APPLETON, ARKENDALE, ARLINGTON, ARNOLD, BALLSTON, BALTIMORE, BARCROFT, BARKSDALE, BAY VIEW, BETHESDA, BLAKE, BOHEMIAS MILLS, BOWIE, BOYDS, BRANTWOOD, BROKENBURG, BROOKFIELD, BROOMES ISLAND, BURKE, BYNUM, CALIFORNIA, CALLAWAY, CATONSVILLE, CHANTILLY, CHERRYDALE, CHESAPEAKE BEACH, CLARKSVILLE, CLINTON, COLLEGE PARK, COLUMBIA, COVE POINT, DAHLGREN, DALE CITY, DAMERON, DRUM POINT, DUNDALK, DUNKIRK, EDGEWOOD, ELDERSBURG, ESSEX, FAIRFAX, FAIRFAX STATION, FALLS CHURCH, FALMOUTH, FELLS POINT, FOUR CORNERS, FREDERICKSBURG, GAITHERSBURG, GAMBER, GARRISONVILLE, GATEWOOD, GERMANTOWN, GLEN BURNIE, GLENDIE, GLENMONT, GREENBELT, HARFORD FURNACE, HICKORY, HISTORIC ELLICOTT CITY, INDEPENDENT HILL, LAKE RIDGE, LANGLEY, LEXINGTON PARK, LONG BEACH, MAGNOLIA, MANASSAS, MANASSAS PARK, MASSAPONAX, MCLEAN, MONTCLAIR, MONTPELIER, MOUNT HARMONY, PARK HEIGHTS, PARKVILLE, PARTLOW, PINEY POINT, POST OAK, RANDALLSTOWN, REAGAN NATIONAL AIRPORT, RESTON, RIDGE, RIDGEWAY, RIVERCREST, ROLLINS FORK, ROSSLYN, SEVERN, SEVERNA PARK, SHILOH, SILVER SPRING, SIMPSONVILLE, SOTTERLEY, SOUTH GATE, SPOTSYLVANIA COURT, ST. CHARLES, SUITLAND-SILVER HILL, TANTALLON, TOWSON, WALDORF, WASHINGTON, WESTMINSTER, WIDEWATER, WOODBRIDGE, WOODLAWN, AND WOODSTOCK.

Flood Watch issued July 9 at 5:46PM EDT until July 9 at 11:00PM EDT by NWS Baltimore MD/Washington DC

Effective: Thu July 9, 2026, 5:46 PM
Expires: Thu July 9, 2026, 11:00 PM

* WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...Washington DC, and portions of Maryland, including the following areas, Anne Arundel, Carroll, Cecil, Central and Southeast Howard, Central and Southeast Montgomery, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford and Southern Baltimore, and northern Virginia, including the following areas, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park and Fairfax. * WHEN...Until 11 PM EDT this evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS... - Clusters of strong to severe thunderstorms will continue to push across the region through this evening. With a continued tropical air mass over the area, very heavy rainfall rates are possible in many of thee storms. These rates could approach 2 to 4 inches per hour. The most vulnerable locations will be urbanized areas along I-95 as well as areas which have experienced heavy rainfall in recent days. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information.

You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.