Tropical Storm Isaias moved up the east coast, passing through southern Maryland on the morning of Tuesday, August 4th, 2020, spawning several tornadoes as well as flooding rain and tropical storm force winds.
Storm total rainfall ranged from 2 to 4 inches near Interstate 95 to as much as 9 inches in Calvert County east of Interstate 95. The heavy rain led to numerous incidents of flooding and flash flooding, especially near and east of Interstate 95.
The highest sustained wind of 46 knots was reported at Bishops Head and the highest peak gust of 63 knots was also reported at Bishops Head.
There were three tornadoes associated with Isaias over southern Maryland and there were also numerous reports of downed trees from tropical storm force winds, especially near and east of Interstate 95.
A storm surge of 1 to 2 feet occurred along the western shore of the Chesapeake Bay and the shore of the Tidal Potomac River. This did result in minor tidal Flooding in Washington DC.

Tropical Storm in CHARLES, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Isolated reports of trees down across the county, but no significant damage reported.

Tropical Storm in ST. MARY'S, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 750.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Tropical Storm Force winds observed at Patuxent River Naval Air Station ASOS (KNHK) with sustained winds of 40 mph at 8:04 AM EST, and a peak wind gust of 58 mph at 9:12 AM EST. Also observed at St. Indigoes MD ASOS (KNUI) with sustained winds of 30 mph at 7:53 AM EST, and a peak wind gust of 52 mph at 8:35 AM EST. Dozens of reports of trees down in a few areas as a result of these winds, one of which fell onto a vehicle in motion, killing the motorist. There was also an EF-0 tornado near Scotland, MD and an EF-1 tornado near Piney Point, MD.

Flood in CALVERT, MARYLAND
From 04-AUG-20 10:15:00 to 04-AUG-20 12:00:00 (EST-5)
Location: PORT REPUBLIC
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

MD 765 was closed at Parkers Creek Road due to high water.

Flood in CALVERT, MARYLAND
From 04-AUG-20 10:15:00 to 04-AUG-20 12:00:00 (EST-5)
Location: PRINCE FREDERICK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Several portions of Route 4 were closed due to high water.

Tropical Storm in ANNE ARUNDEL, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Sustained winds of 39 mph reported at the U.S. Naval Academy ASOS (KNAK) at 7:56 AM EST, with a peak wind gust of 56 mph at 8:07 AM EST. Isolated reports of trees down across the county, but no significant damage reported.

Tropical Storm in CALVERT, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 750.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Dozens of trees reported down countywide from tropical storm force wind gusts. An EF-1 tornado also occurred near Plum Point, and another near Solomons.

Flood in BALTIMORE, MARYLAND
From 04-AUG-20 12:00:00 to 04-AUG-20 14:00:00 (EST-5)
Location: LUTZ HILL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Multiple roads were closed because the Back River was out of its banks.

Flash Flood in HARFORD, MARYLAND
From 04-AUG-20 09:24:00 to 04-AUG-20 11:45:00 (EST-5)
Location: SINGER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The water level rapidly rose above flood stage along the Otter Point Creek at Edgewood. The water level crested at 8.67 feet at 10:01 AM August 4th. Winter Run Road was flooded near Singer Road.

Tropical Storm in PRINCE GEORGES, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Sustained winds of 31 mph reported at the Andrews Air Force Base ASOS (KADW) at 8:03 AM EST, with a peak wind gust of 44 mph at 8:19 AM EST. Isolated reports of trees down across the county, but no significant damage reported.

Flash Flood in BALTIMORE, MARYLAND
From 04-AUG-20 09:00:00 to 04-AUG-20 11:43:00 (EST-5)
Location: LINHIGH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The water rapidly rose above flood stage along the Whitemarsh Run in Whitemarsh. The water crested at 13.02 feet at 10:25 AM EST on August 4th. The Town Center Court was flooded.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 07:56:00 to 04-AUG-20 10:00:00 (EST-5)
Location: CLEMENTS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The water level rapidly rose above flood stage along the St. Clement Creek in Clements. The water level crested at 9.09 feet at 10:00 AM on August 4th. Water approached Route 234 and 242. Water also approached homes near the creek north of Clements.

Flood in PRINCE GEORGE'S, MARYLAND
From 04-AUG-20 08:53:00 to 04-AUG-20 10:53:00 (EST-5)
Location: BERWYN HGTS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Northbound Kenilworth Ave. closed due to high water at Rottenhouse St.

Flood in CALVERT, MARYLAND
From 04-AUG-20 10:00:00 to 04-AUG-20 12:00:00 (EST-5)
Location: CHANEYVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

MD-262 closed due to flooding of Chew Creek.

Tornado in CALVERT, MARYLAND
From 04-AUG-20 06:33:00 to 04-AUG-20 06:38:00 (EST-5)
Location: BREEZY PT
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

At 7:33 AM EDT, an EF-1 tornado came onshore at Plum
Point near Beach Drive approximately 5 miles east of Huntingtown,
MD. The tornado moved west along Shore Drive, uprooting numerous
trees and snapping and twisting others. A large tree halfway
along Shore Drive fell on a house, causing structural damage. The
tornado proceeded to move to the end of Shore Drive and shifted
southwest along Ridge Road causing trees to snap about 20 feet up
and fall in multiple directions. Some trees that were snapped were
a foot and a half in diameter.
The tornado then moved across Plum Point Creek and the grassy wetlands
toward Tobacco Road.  A swath of trees had their tops broken off east of
Tobacco Road and fell mainly in a south to west direction.
The tornado then proceeded up Tobacco Road near Tobacco Lane, and
moved northward towards Breezy Point Road. Peak winds in the tornado
were estimated to have reached 90 mph here. Over 30 trees were
uprooted, and some were broken in half. A house had a tree fall on
it along the Tobacco Road area, and windows were blown in on another
house. Tobacco Road had over 10 trees fall westward over the road
along with multiple power poles.  A 75 to 100 yard path of tree
damage was observed east of Tobacco Road with trees falling in
multiple directions. The area of Tobacco Road from Pinewood Terrace
to Tobacco Lane became impassable due to the tree and power line
damage, and the Breezy Point area became cut off from the main road.
The tornado moved west after passing Breezy Point Road and caused
numerous trees to fall along Route 261/Bayside Road near Bristol
Drive. A large tree near the intersection of Route 261 and Bristol
Drive fell on a house. The tree damage path was observed up to
50 to 75 feet down the north end of Bristol Drive.
The tornado then crossed MD-261, downing more trees and tearing siding from homes near the intersection of Holbrook Lane and Pleasant Court. One tree fell into a house, knocking out a window. No further tornadic damage was observed beyond this point.

Flood in MONTGOMERY, MARYLAND
From 04-AUG-20 10:39:00 to 04-AUG-20 12:39:00 (EST-5)
Location: BYFORDE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Beech Dr. closed due to flooding along Rock Creek.

Flood in ANNE ARUNDEL, MARYLAND
From 04-AUG-20 11:14:00 to 04-AUG-20 13:14:00 (EST-5)
Location: RIVA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

MD-214 closed due to flooding near Beards Creek.

Tornado in ST. MARY'S, MARYLAND
From 04-AUG-20 05:27:00 to 04-AUG-20 05:31:00 (EST-5)
Location: SCOTLAND
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

At 6:27 AM EDT, a tornado rated EF-0 caused damage near Scotland, MD.
The survey found tree damage along a portion of Point Lookout
Road between St. Gabriels Manor Way and Fresh Pond Neck Road.
First evidence of tornado touchdown was near the intersection of
St. Gabriels Manor Way and Route 5/Point Lookout Rd where numerous
tree limbs were down.
As the tornado moved north-northwest, numerous trees were snapped
or downed all along the 12800 block of Point Lookout Rd. An
entire row of cedar trees was pushed over behind one residence. A
resident who was home when the tornado passed over stated they
heard a violent roaring sound, the house visibly shook, and then
it was over in a matter of seconds. A row of trees behind the
residence was uprooted during this time.
The tornado lifted shortly before crossing Fresh Pond Neck Road at
Point Lookout Rd and then touched down further north near the
intersection of Curleys Rd and Point Lookout Rd knocking down a
tree on Curleys Rd. The tornado finally knocked down a tree on a
farm just northeast of the aforementioned intersection before
lifting at 6:31 AM EDT.

Flood in ANNE ARUNDEL, MARYLAND
From 04-AUG-20 11:25:00 to 04-AUG-20 13:25:00 (EST-5)
Location: RAYNOR HGTS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Furnace Ave. closed due to flooding at the Howard/Anne Arundel County line.

Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 12:00:00 to 04-AUG-20 14:00:00 (EST-5)
Location: LEONARDTOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flooding on McIntosh Run near Potato Farm Rd. Water is 2-3 feet deep and approximately 600 feet wide.

Tornado in ST. MARY'S, MARYLAND
From 04-AUG-20 05:32:00 to 04-AUG-20 05:41:00 (EST-5)
Location: TALL TIMBERS
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

At 6:32 AM EDT, a tornado rated EF-1 formed soon after the storm
moved northwest of Piney Point, MD. Consistent tree damage began
along Piney Point Road between Tall Timbers and Valley Lee. An
aerial survey was conducted, and a path of snapped and uprooted
trees about 75 to 100 yards wide was noted extending to the
northwest through the woods and fields of rural St. Marys
County. Some roads having multiple trees downed along this path
included Blake Creek Road, Richey Road, and Medleys Neck Road.
Homes were damaged by falling trees, including one along Medleys
Neck Road near the intersection with Scarlet Tanager Way.
The tornado crossed Route 5/Point Lookout Road near the
intersection with Lightfoot Way. Here there was also significant
tree damage. Large trees were uprooted damaging a shed and a home.
A mobile home/camper was blown over on its side. The tornado then
dissipated at 6:41 AM EDT.

Flood in PRINCE GEORGE'S, MARYLAND
From 04-AUG-20 14:00:00 to 05-AUG-20 07:21:00 (EST-5)
Location: COLLINGTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Western Branch Patuxent River near Upper Marlboro, MD exceeded the 11 foot flood stage during the indicated period. Much of Race Track Rd. flooded between Marlboro Pike and the community center. The peak level of 13.04 feet occurred at 8:15 PM on the 4th.

Flood in CHARLES, MARYLAND
From 04-AUG-20 18:19:00 to 05-AUG-20 15:45:00 (EST-5)
Location: INDIAN HD MRYLND ARP
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on Mattawoman Creek near Pomonkey, MD exceeded the 7 foot flood stage during the indicated period. Pomfret Rd. is flooded and closed. The peak level of 8.06 feet occurred at 11:00 PM on the 4th.

Tornado in CALVERT, MARYLAND
From 04-AUG-20 05:52:00 to 04-AUG-20 05:53:00 (EST-5)
Location: COSTER
Tornado F-scale: EF0
Property damage: 250.00K
Reported by: NWS Storm Survey

One of four confirmed tornadoes spawned by Tropical Storm Isaias
over lower southern Maryland touched down along Point Patience Drive
between the Navy Recreation Center Solomons Fishing Pier and Third
Cove. The tornado tracked northeastward roughly along Patuxent
Drive, uprooting and snapping numerous trees along its path. The
trees fell in a convergent manner over a path of nearly one mile
long and about 175 yards wide, indicating a tornadic circulation was
in contact with the ground. Two recreational vehicles on the Navy
facility were smashed by falling trees. Fortunately there were no
occupants at the time. Trees fell on numerous recreational
facilities on the compound, and damage was noted to outdoor
umbrellas at the pool which were rated for hurricane force winds.
NWS 88D Doppler Radar, as well as the FAA Terminal Doppler Weather Radars
TDCA and TADW all indicated strong rotation over this area.
The tornadic damage ended near the north end of the Naval facility,
and no damage was noted in the adjacent residential community to the
north. Many other scattered trees were knocked down all across
Calvert County and lower southern Maryland due to winds associated
with Tropical Storm Isaias.

Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 05:36:00 to 04-AUG-20 22:19:00 (EST-5)
Location: GREAT MILLS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the St. Marys River near Great Mills, MD exceeded the 6 foot flood stage during the indicated period. Widespread flooding occurred in Great Mills, with water approaching homes and businesses. The peak level of 11.57 feet occurred at 10:15 AM.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 06:12:00 to 04-AUG-20 10:00:00 (EST-5)
Location: GREAT MILLS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 5 was flooded and closed at the Intersection of Route 246 at the St. Marys River.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 06:37:00 to 04-AUG-20 15:00:00 (EST-5)
Location: MECHANICSVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Flowing water covered Mechanicsville Road near Beverly Drive.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 06:45:00 to 04-AUG-20 10:00:00 (EST-5)
Location: REDGATE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 5 was closed due to high water at Moll Dyers Run.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 08:01:00 to 04-AUG-20 10:00:00 (EST-5)
Location: CLEMENTS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 242 was closed due to high water at Locust Run prior to Doctor Johnson Road.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 08:07:00 to 04-AUG-20 10:00:00 (EST-5)
Location: CHAPTICO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 234 was closed just west of Chaptico at Chaptico Creek.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 08:13:00 to 04-AUG-20 10:00:00 (EST-5)
Location: AVENUE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 242 was closed due to high water at Oakley Road.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 08:15:00 to 04-AUG-20 10:00:00 (EST-5)
Location: GOLDEN BEACH
Flood cause: Heavy Rain
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Broadcast Media

MD-6 New Market Turner Road was washed away over Persimmon Creek.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 08:29:00 to 04-AUG-20 10:00:00 (EST-5)
Location: LEONARDTOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 243 was closed due to high water at Nelson Run near Leonardtown.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 08:38:00 to 04-AUG-20 10:00:00 (EST-5)
Location: REDGATE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 4 was closed at Glebe Run near Brown Road due to high water.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 09:12:00 to 04-AUG-20 10:00:00 (EST-5)
Location: LEONARDTOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 5 was close due to high water at McIntosh Run near Leonardtown.

Flash Flood in ST. MARY'S, MARYLAND
From 04-AUG-20 09:47:00 to 04-AUG-20 10:00:00 (EST-5)
Location: CLEMENTS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A water rescue was reported on Budds Creek Road in Clements.

Flash Flood in CHARLES, MARYLAND
From 04-AUG-20 08:50:00 to 04-AUG-20 10:30:00 (EST-5)
Location: LOVES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 381 was closed at Swanson Creek due to high water. There were water rescues reported with two vehicles and at least two occupants.

Tropical Storm in CENTRAL AND SOUTHEAST HOWARD, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 5.00K
Crop damage: 0.00K
Reported by: 911 Call Center

The Howard County 911 Center received about a dozen calls for trees, branches, and wires down.

Tropical Storm in CENTRAL AND SOUTHEAST MONTGOMERY, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Numerous trees were down throughout southeastern Montgomery County. There was an injury due to a tree down on an occupied vehicle near the intersection of West Lake Drive and Tuckerman Lane.

Flash Flood in CHARLES, MARYLAND
From 04-AUG-20 09:15:00 to 04-AUG-20 10:30:00 (EST-5)
Location: RYCEVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Water was flowing across north Ryceville Road.

Flash Flood in BALTIMORE, MARYLAND
From 04-AUG-20 09:30:00 to 04-AUG-20 11:00:00 (EST-5)
Location: DUNDALK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 695 was closed due to high water near Belclare Road.

Tropical Storm in NORTHWEST HOWARD, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 5.00K
Crop damage: 0.00K
Reported by: 911 Call Center

The Howard County 911 Center received about a dozen calls for trees, branches, and wires down.

Tropical Storm in SOUTHEAST HARFORD, MARYLAND
From 04-AUG-20 05:00:00 to 04-AUG-20 11:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A tropical storm force wind gust of 36 knots was reported near Hickory.

Flash Flood in BALTIMORE, MARYLAND
From 04-AUG-20 09:58:00 to 04-AUG-20 11:00:00 (EST-5)
Location: POPLAR
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Maryland Route 7 was closed near Mohrs Lane due to high water.

Flood in CALVERT, MARYLAND
From 04-AUG-20 10:15:00 to 04-AUG-20 12:00:00 (EST-5)
Location: STOAKLEY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

MD 263 at Hunting Creek was closed due to high water.