A cold front passed through the area on the 27th. Ahead of the boundary, a southerly flow led to plenty of moisture an unstable atmosphere. A potent upper-level low caused stronger winds aloft as well. Some thunderstorms associated with the cold front produced gusty winds due to the instability and stronger winds aloft.

Marine Hail in PATAPSCO RIVER INCLUDING BALTIMORE HARBOR, ATLANTIC NORTH
From 27-JUL-18 16:30:00 to 27-JUL-18 16:30:00 (EST-5)
Location: ORIOLE PARK AT CAMDEN YARDS (BLTPC)
Magnitude: 1.25 
Reported by: Public

Half dollar sized hail was reported near Baltimore.

Marine Thunderstorm Wind in TIDAL POTOMAC INDIAN HD TO COBB IS MD, ATLANTIC NORTH
From 27-JUL-18 12:46:00 to 27-JUL-18 13:21:00 (EST-5)
Location: MONROE CREEK (MON)
Magnitude: 36.00 MG
Reported by: Buoy

Wind gusts up to 36 knots were reported at Monroe Creek.

Marine Thunderstorm Wind in TIDAL POTOMAC COBB IS MD TO SMITH PT VA, ATLANTIC NORTH
From 27-JUL-18 13:19:00 to 27-JUL-18 13:29:00 (EST-5)
Location: COBB POINT (COB)
Magnitude: 45.00 MG
Reported by: Buoy

Wind gusts up to 45 knots were reported at Cobb Point.

Marine Thunderstorm Wind in TIDAL POTOMAC INDIAN HD TO COBB IS MD, ATLANTIC NORTH
From 27-JUL-18 14:01:00 to 27-JUL-18 14:26:00 (EST-5)
Location: POTOMAC LIGHT 33 (LT3)
Magnitude: 50.00 MG
Reported by: Buoy

Wind gusts in excess of 50 knots were reported at Potomac Light.

Marine Thunderstorm Wind in TIDAL POTOMAC COBB IS MD TO SMITH PT VA, ATLANTIC NORTH
From 27-JUL-18 15:20:00 to 27-JUL-18 15:20:00 (EST-5)
Location: POTOMAC POINT LOOKOUT BUOY (44042)
Magnitude: 34.00 EG
Reported by: Buoy

Wind gusts in excess of 30 knots were reported at Potomac Point Lookout.

Marine Thunderstorm Wind in TIDAL POTOMAC COBB IS MD TO SMITH PT VA, ATLANTIC NORTH
From 27-JUL-18 14:36:00 to 27-JUL-18 14:36:00 (EST-5)
Location: ST INIGOES (KNUI)
Magnitude: 38.00 MG
Reported by: Buoy

A wind gust of 38 knots was reported at Cove Point.

Marine Thunderstorm Wind in CHESAPEAKE BAY SANDY PT TO N BEACH MD, ATLANTIC NORTH
From 27-JUL-18 15:30:00 to 27-JUL-18 15:40:00 (EST-5)
Location: GREENBERRY POINT (GBY)
Magnitude: 35.00 MG
Reported by: Buoy

Wind gusts up to 35 knots were reported at the Annapolis Buoy.

Marine Thunderstorm Wind in CHESAPEAKE BAY N BEACH TO DRUM PT MD, ATLANTIC NORTH
From 27-JUL-18 14:50:00 to 27-JUL-18 14:50:00 (EST-5)
Location: ST INIGOES (KNUI)
Magnitude: 34.00 EG
Reported by: Buoy

A wind gust in excess of 30 knots was reported at Gooses Reef.

Marine Thunderstorm Wind in CHOPTANK RIVER TO CAMBRIDGE MD AND THE LITTLE CHOPTANK RIVER, ATLANTIC NORTH
From 27-JUL-18 14:59:00 to 27-JUL-18 14:59:00 (EST-5)
Location: GOOSES REEF BUOY (44062)
Magnitude: 34.00 EG
Reported by: Buoy

A wind gust in excess of 30 knots was reported at Black Walnut Harbor.

Marine Thunderstorm Wind in CHESAPEAKE BAY SANDY PT TO N BEACH MD, ATLANTIC NORTH
From 27-JUL-18 15:26:00 to 27-JUL-18 15:41:00 (EST-5)
Location: TOLLY POINT (TOL)
Magnitude: 47.00 MG
Reported by: Buoy

Wind gusts of 34 to 47 knots were reported at Tolly Point.

Marine Thunderstorm Wind in CHESAPEAKE BAY SANDY PT TO N BEACH MD, ATLANTIC NORTH
From 27-JUL-18 15:29:00 to 27-JUL-18 15:39:00 (EST-5)
Location: GREENBERRY POINT (GBY)
Magnitude: 38.00 MG
Reported by: Buoy

Wind gusts up to 38 knots were reported at Greenberry Point.

Marine Thunderstorm Wind in TIDAL POTOMAC COBB IS MD TO SMITH PT VA, ATLANTIC NORTH
From 27-JUL-18 15:40:00 to 27-JUL-18 15:40:00 (EST-5)
Location: POTOMAC POINT LOOKOUT BUOY (44042)
Magnitude: 34.00 EG
Reported by: Buoy

Wind gusts in excess of 30 knots were reported at Potomac Point Lookout.

Marine Thunderstorm Wind in CHESAPEAKE BAY N BEACH TO DRUM PT MD, ATLANTIC NORTH
From 27-JUL-18 16:00:00 to 27-JUL-18 16:10:00 (EST-5)
Location: GOOSES REEF BUOY (44062)
Magnitude: 41.00 MG
Reported by: Buoy

Wind gusts of 37 to 41 knots were reported at Gooses Reef.

Marine Thunderstorm Wind in CHESAPEAKE BAY POOLES IS TO SANDY PT MD, ATLANTIC NORTH
From 27-JUL-18 16:27:00 to 27-JUL-18 16:27:00 (EST-5)
Location: HART MILLER ISLAND (HRT)
Magnitude: 34.00 EG
Reported by: Buoy

Wind gusts in excess of 30 knots were reported at Hart Miller.

Marine Thunderstorm Wind in CHESAPEAKE BAY N OF POOLES IS MD, ATLANTIC NORTH
From 27-JUL-18 17:16:00 to 27-JUL-18 17:26:00 (EST-5)
Location: GROVE POINT (GVP)
Magnitude: 35.00 MG
Reported by: Buoy

Wind gusts up to 35 knots were reported at Grove Point.

Marine Thunderstorm Wind in TIDAL POTOMAC INDIAN HD TO COBB IS MD, ATLANTIC NORTH
From 27-JUL-18 14:03:00 to 27-JUL-18 14:08:00 (EST-5)
Location: BABAR POINT (BAB)
Magnitude: 47.00 MG
Reported by: Buoy

A wind gust of 47 knots was reported at Pylons DAH.

Marine Thunderstorm Wind in TIDAL POTOMAC COBB IS MD TO SMITH PT VA, ATLANTIC NORTH
From 27-JUL-18 15:04:00 to 27-JUL-18 15:09:00 (EST-5)
Location: POINT LOOKOUT (PTL)
Magnitude: 39.00 MG
Reported by: Buoy

Wind gusts of 36 to 39 knots were reported at Point Lookout.

Marine Thunderstorm Wind in TIDAL POTOMAC COBB IS MD TO SMITH PT VA, ATLANTIC NORTH
From 27-JUL-18 15:00:00 to 27-JUL-18 15:10:00 (EST-5)
Location: POTOMAC POINT LOOKOUT BUOY (44042)
Magnitude: 39.00 MG
Reported by: Buoy

Wind gusts of 37 to 39 knots were reported at Potomac Point Lookout.

Marine Thunderstorm Wind in CHESAPEAKE BAY SANDY PT TO N BEACH MD, ATLANTIC NORTH
From 27-JUL-18 15:32:00 to 27-JUL-18 15:37:00 (EST-5)
Location: KENT ISLAND (KNT)
Magnitude: 34.00 EG
Reported by: AWOS

Wind gusts in excess of 30 knots were reported at Kent Island.

Marine Thunderstorm Wind in TIDAL POTOMAC INDIAN HD TO COBB IS MD, ATLANTIC NORTH
From 27-JUL-18 14:00:00 to 27-JUL-18 14:00:00 (EST-5)
Location: CUCKOLD CREEK (CCK)
Magnitude: 34.00 EG
Reported by: Buoy

Wind gusts in excess of 30 knots were reported at Cuckold Creek.

Marine Thunderstorm Wind in TIDAL POTOMAC INDIAN HD TO COBB IS MD, ATLANTIC NORTH
From 27-JUL-18 13:58:00 to 27-JUL-18 13:58:00 (EST-5)
Location: BABAR POINT (BAB)
Magnitude: 34.00 EG
Reported by: Buoy

Wind gusts in excess of 30 knots were reported at Pylons DAH.

Marine Thunderstorm Wind in TIDAL POTOMAC INDIAN HD TO COBB IS MD, ATLANTIC NORTH
From 27-JUL-18 14:05:00 to 27-JUL-18 14:10:00 (EST-5)
Location: CUCKOLD CREEK (CCK)
Magnitude: 38.00 MG
Reported by: Buoy

Wind gusts of 34 to 38 knots were reported Cuckold Creek.

Marine Thunderstorm Wind in TIDAL POTOMAC INDIAN HD TO COBB IS MD, ATLANTIC NORTH
From 27-JUL-18 14:07:00 to 27-JUL-18 14:07:00 (EST-5)
Location: BABAR POINT (BAB)
Magnitude: 48.00 MG
Reported by: Buoy

A wind gust of 48 knots were reported at Baber Point.

Marine Thunderstorm Wind in CHESAPEAKE BAY SANDY PT TO N BEACH MD, ATLANTIC NORTH
From 27-JUL-18 16:00:00 to 27-JUL-18 16:00:00 (EST-5)
Location: THOMAS POINT (TPLM2)
Magnitude: 34.00 EG
Reported by: Buoy

Wind gusts in excess of 30 knots were reported at Thomas Point Lighthouse.