A sea breeze front helped trigger slow moving and regenerating thunderstorms across southeastern Sussex County.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PHI wrote it up.
A sea breeze front helped trigger slow moving and regenerating thunderstorms across southeastern Sussex County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Aug 17, 12:43 PM EST, 1 hour 32 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 143 PM EDT TUE AUG 17 2010 .SYNOPSIS... A FRONTAL BOUNDARY FROM THE NORTHWEST WILL CONTINUE TO DROP THROUGH OUR REGION TODAY. THE BOUNDARY IS FORECAST TO STALL ACROSS VIRGINIA AND MARYLAND FOR TONIGHT AND WEDNESDAY. LOW PRESSURE RIDING ALONG THE FRONT IS EXPECTED TO PASS OFF THE MIDDLE ATLANTIC COAST EARLY ON THURSDAY, TAKING THE BOUNDARY ALONG WITH IT. WEAK HIGH PRESSURE SHOULD FOLLOW FOR THURSDAY INTO THURSDAY NIGHT. ANOTHER FRONTAL BOUNDARY FROM THE NORTHWEST IS FORECAST TO ARRIVE ON FRIDAY AND IT IS EXPECTED TO MEANDER OVER OR NEAR OUR REGION DURING THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AT 1100 AM, THE FRONTAL BOUNDARY HAD REACHED SOUTHERN NJ AND NORTHERN DE WITH SUBSTANTIALLY HIGHER DEW POINT READINGS TO THE SOUTH OF THE FRONT. IT SHOULD BE MOSTLY SUNNY ACROSS OUR NORTHERN AND CENTRAL COUNTIES TODAY, EVEN AS SOME CIRRUS STREAMS OVERHEAD FROM THE WEST. FOR OUR SOUTHERN COUNTIES WE WILL CARRY A PARTLY SUNNY FORECAST. LOWERED POPS FOR THIS AFTERNOON TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND SOUTH OF THE FRONTAL BOUNDARY. EVEN WITH THE FRONTAL PASSAGE, TODAY SHOULD BE RATHER WARM. MAXIMUM TEMPERATURES ARE FORECAST TO BE MAINLY IN THE LOWER 90S, WITH READINGS IN THE 80S UP NORTH. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... THE FRONT IS EXPECTED TO SINK TO OUR SOUTH FOR TONIGHT AND WEDNESDAY. WEAK WAVES OF LOW PRESSURE ARE FORECAST TO RIDE ALONG THE FRONT. THE PATTERN WILL SPREAD RAIN UP INTO OUR REGION, MAINLY OUR SOUTHERN COUNTIES. BEING THE THE ATMOSPHERE TO THE SOUTH OF THE FRONT IS VERY MOIST, THE POTENTIAL EXISTS FOR SOME HEAVY RAIN IN OUR SOUTHERN COUNTIES FROM WEDNESDAY INTO WEDNESDAY NIGHT. THE RAINFALL GRADIENT ACROSS OUR REGION SHOULD BE RATER TIGHT AND IT IS QUITE POSSIBLE THAT THE POCONOS AND EXTREME NORTHERN NEW JERSEY MAY RECEIVE LITTLE RAIN FROM THIS EVENT. FOR NOW WE WILL SIMPLY MENTION THE POSSIBILITY OF HEAVY RAIN IN THE HAZARDOUS WEATHER OUTLOOK. ALSO, BASED ON THE PATTERN WE HAVE WORDED THE FORECAST AS RAIN AND NOT SHOWERS. WITH AN ONSHORE FLOW, CONDITIONS NEAR THE SURFACE WILL REMAIN STABLE. HOWEVER, SOME ELEVATED CONVECTION IS NOT OUT OF THE QUESTION. WITH THE CLOUD COVER ON WEDNESDAY, TEMPERATURES MAY NOT EXCEED THE LOWER 80S. AN AREA OF LOW PRESSURE RIDING ALONG THE FRONT IS FORECAST TO PULL THE BOUNDARY OFF THE MIDDLE ATLANTIC COAST EARLY ON THURSDAY, BRINGING AN END TO THE RAIN IN OUR REGION. SOME CLEARING IS EXPECTED TO TAKE PLACE ON THURSDAY AS DRIER AIR FILTERS DOWN FROM THE NORTH. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... IT APPEARS AS THOUGH THE UPPER LEVEL TROUGH OVER THE NORTHEASTERN STATES WILL GET REINFORCED OVER THE WEEKEND. ANOTHER FRONTAL BOUNDARY FROM THE NORTHWEST IS FORECAST TO DROP INTO OUR REGION ON FRIDAY, INITIALLY, IT SHOULD HAVE LITTLE MOISTURE ASSOCIATED WITH IT. THE BOUNDARY IS EXPECTED TO STALL IN OUR VICINITY ON SATURDAY BEFORE LIFTING BACK TO THE NORTH. LOW PRESSURE PASSING TO OUR NORTH SHOULD PULL THE FRONT THOUGH OUR REGION AND OFF THE COAST ON SUNDAY NIGHT. BASED ON THE EXPECTED SCENARIO, THE BEST CHANCES FOR PRECIPITATION IN THE LONG TERM FORECAST PERIOD SHOULD BE ON SUNDAY. TEMPERATURES DURING THE PERIOD FROM FRIDAY THROUGH MONDAY ARE ANTICIPATED TO BE SEASONABLE. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. A WEAKENING COLD FRONT HAS NEARLY STALLED FROM FAR SOUTHEASTERN NEW JERSEY DOWN THROUGH THE DELMARVA. BEHIND THIS FRONT, DRIER AIR HAS WORKED INTO THE AREA ALLOWING FOR LIMITED CUMULUS DEVELOPMENT. HOWEVER, A STRENGTHENING UPPER-LEVEL JET IS TOSSING SOME MID TO MOSTLY HIGH CLOUDS ACROSS THE AREA. ALONG AND SOUTH OF THE FRONT, DEEPER MOISTURE IS HELPING TO INITIATE ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS. ONE SHOWER/STORM THAT MAY HAVE BEEN HELPED BY A DEVELOPING SEA BREEZE IS NEAR KACY AS OF 1730Z. THEREFORE, WE USED A VCSH FOR A LITTLE WHILE TO ACCOUNT FOR THIS. THE MAJORITY OF THIS ACTIVITY SHOULD TEND TO STAY SOUTH AND EAST OF KACY AND KMIV, BUT WITH HIGHER DEW POINTS HANGING ON, SOME ISOLATED ACTIVITY IS POSSIBLE FOR AWHILE THIS AFTERNOON. ALSO WITH THE DEEPER MOISTURE STILL AT KACY AND KMIV, SOME STRATOCUMULUS WILL LINGER FOR AWHILE. IT DOES APPEAR THAT SOME DRYING ARRIVES EVEN HERE LATER, THEREFORE WILL NOT FAVOR ANY FOG TONIGHT. THE MID AND ESPECIALLY HIGH CLOUDS WILL CONTINUE TO MOVE ACROSS THE AREA TONIGHT AS AN AREA OF LOW PRESSURE ORGANIZES TO OUR WEST ALONG THE FRONTAL BOUNDARY. WHILE A NORTHWESTERLY WIND UNDER 10 KNOTS OCCURS INTO THIS EVENING, THE FLOW IS LIGHT ENOUGH WERE SOME LOCAL WIND SHIFTS TO THE SOUTHWEST TO EVEN SOUTHEAST WILL BE POSSIBLE. SOME OF THIS IS OCCURRING AT KPHL AND KACY AS OF 1730Z. THE LATTER IS MORE OF A SEA BREEZE FRONT DEVELOPING. MOST TERMINALS WILL HAVE A LIGHT AND VARIABLE WIND TONIGHT, ALTHOUGH SOME SLIGHT INCREASE AND SHIFT TO THE NORTHEAST IS EXPECTED TOWARD SUNRISE WEDNESDAY. FOR WEDNESDAY, AN AREA OF LOW PRESSURE WILL BE APPROACHING FROM THE SOUTHWEST THEREFORE THE CLOUDS WILL INCREASE AND LOWER THROUGH THE DAY. WHILE THERE IS SOME UNCERTAINTY STILL WITH THE EXACT TRACK AND PLACEMENT OF THE MAIN RAIN AREA, THERE IS A CONSENSUS THAT THE HEAVIER RAIN OCCURS SOUTH AND EAST OF KPHL. OUR CONFIDENCE IS LOWER THAN AVERAGE REGARDING THE TIMING, THEREFORE WE CARRIED SOME LIGHT RAIN FROM KPHL/KPNE SOUTH AND EAST STARTING AROUND MIDDAY. THE CEILINGS AND VISIBILITIES SHOULD LOWER DURING THE AFTERNOON AND BEYOND THE TAF PERIOD AS THE STORM SYSTEM MOVES THROUGH /THIS WAS INDICATED IN THE KPHL 30-HOUR TAF/. KTTN, KABE AND KRDG MAY NOT SEE MUCH RAIN FROM THIS AND PROBABLY AFTER 18Z WEDNESDAY, SO WE DID NOT INCLUDE A MENTION FOR NOW. A LIGHT NORTHEAST TO EAST WIND WILL INCREASE TO NEAR 10 KNOTS DURING THE DAY. OUTLOOK... AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE MID ATLANTIC REGION WEDNESDAY NIGHT BEFORE SLIDING TO OUR EAST THURSDAY MORNING. THIS WILL BRING AN AREA OF RAIN TO THE AREA ESPECIALLY SOUTH AND EAST OF KPHL. THERE APPEARS TO BE A SWATH OF HEAVY RAIN MAINLY FOR KMIV AND KACY. SOME THUNDERSTORMS CANNOT BE RULED OUT HOWEVER THIS POTENTIAL LOOKS LOW AT THIS TIME. THIS SYSTEM WILL PRODUCE LOWERED CEILINGS AND VISIBILITIES WITH THE BETTER CONDITIONS PROBABLY AT KABE AND KRDG. THIS SYSTEM MOVES AWAY THURSDAY MORNING WITH IMPROVING CONDITIONS. A WEAK AREA OF HIGH PRESSURE THEN BUILDS IN FOR FRIDAY INTO SATURDAY, HOWEVER A WEAK FRONTAL BOUNDARY MAY SETTLE INTO OUR AREA AND LINGER INTO SUNDAY. && .MARINE... A WEAKENING COLD FRONT WILL CONTINUE TO SETTLE ACROSS THE SOUTHERN WATERS AND DELAWARE BAY THROUGH THIS AFTERNOON BEFORE STALLING IN THE VICINITY. A WIND SHIFT FROM SOUTHWESTERLY TO A WEST/NORTHWEST DIRECTION IS EXPECTED AS THE FRONT MOVES THROUGH. HOWEVER, THE FRONT MAY NOT COMPLETELY CLEAR OUR WATERS, THEREFORE THE WIND DIRECTION FORECAST IS A LITTLE TRICKY. GIVEN THE LIGHT FLOW, A SEA BREEZE TYPE CIRCULATION MAY OCCUR ALLOWING WINDS ESPECIALLY NEARSHORE TO TURN MORE SOUTHERLY. WIND SPEEDS WILL GENERALLY BE IN THE 10 TO 15 KNOT RANGE. A MORE NELY TO ELY DIRECTION WILL DEVELOP TONIGHT. THE STALLED FRONT LOOKS TO BE NEAR OUR SOUTHERN WATERS THROUGH THURSDAY, AS AN AREA OF LOW PRESSURE MOVES UP THE FRONT WEDNESDAY INTO THURSDAY. ATTM, IT APPEARS THAT SINCE THE LOW IS NOT ALL THAT STRONG, CONDITIONS WILL NOT REACH SCA CRITERIA, DESPITE THE ONSHORE FLOW. THE SURFACE LOW MAY BRING WIDESPREAD RAIN AND PERHAPS SOME THUNDERSTORMS TO PORTIONS OF THE AREA, MAINLY ACRS THE SOUTH. THERE ARE, HOWEVER, SOME TIMING AND PLACEMENT UNCERTAINTIES REGARDING THE MAIN PRECIPITATION. HIGH PRESSURE RETURNS FOR FRIDAY, ALTHOUGH A FRONTAL BOUNDARY MAY SETTLE INTO THE AREA FRIDAY NIGHT AND SATURDAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && SYNOPSIS...IOVINO NEAR TERM...SZATKOWSKI/IOVINO SHORT TERM...IOVINO LONG TERM...IOVINO AVIATION...GORSE MARINE...GORSE/NIERENBERG
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 534 AM EDT TUE AUG 17 2010 NJZ001-007>010-012-013-015-019-PAZ054-055-060>062-067>071-180945- SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-WESTERN MONMOUTH- MERCER-NORTHWESTERN BURLINGTON-CARBON-MONROE-BERKS-LEHIGH- NORTHAMPTON-CHESTER-MONTGOMERY-BUCKS-DELAWARE-PHILADELPHIA- 534 AM EDT TUE AUG 17 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NEW JERSEY...NORTHERN NEW JERSEY...NORTHWEST NEW JERSEY...SOUTHERN NEW JERSEY...EAST CENTRAL PENNSYLVANIA...NORTHEAST PENNSYLVANIA AND SOUTHEAST PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. DEZ001>003-MDZ008-012-015-019-020-NJZ016>018-020>023-027-180945- NEW CASTLE-KENT-INLAND SUSSEX-CECIL-KENT MD-QUEEN ANNES-TALBOT- CAROLINE-SALEM-GLOUCESTER-CAMDEN-OCEAN-CUMBERLAND-ATLANTIC-CAPE MAY- SOUTHEASTERN BURLINGTON- 534 AM EDT TUE AUG 17 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL DELAWARE...NORTHERN DELAWARE...SOUTHERN DELAWARE...NORTHEAST MARYLAND AND SOUTHERN NEW JERSEY. .DAY ONE...TODAY AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. RAIN MAY BE HEAVY AT TIMES FROM WEDNESDAY INTO WEDNESDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. ANZ430-431-450>455-180945- DELAWARE BAY WATERS NORTH OF EAST POINT NJ TO SLAUGHTER BEACH DE- DELAWARE BAY WATERS SOUTH OF EAST POINT NJ TO SLAUGHTER BEACH DE- COASTAL WATERS FROM SANDY HOOK TO MANASQUAN INLET NJ OUT 20 NM- COASTAL WATERS FROM MANASQUAN INLET TO LITTLE EGG INLET NJ OUT 20 NM- COASTAL WATERS FROM LITTLE EGG INLET TO GREAT EGG INLET NJ OUT 20 NM- COASTAL WATERS FROM GREAT EGG INLET TO CAPE MAY NJ OUT 20 NM- COASTAL WATERS FROM CAPE MAY NJ TO CAPE HENLOPEN DE OUT 20 NM- COASTAL WATERS FROM CAPE HENLOPEN TO FENWICK ISLAND DE OUT 20 NM- 534 AM EDT TUE AUG 17 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS AND DELAWARE BAY WATERS. .DAY ONE...TODAY AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. DEZ004-NJZ014-024>026-180945- DELAWARE BEACHES-EASTERN MONMOUTH-ATLANTIC COASTAL CAPE MAY- COASTAL ATLANTIC-COASTAL OCEAN- 534 AM EDT TUE AUG 17 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN DELAWARE...CENTRAL NEW JERSEY AND SOUTHERN NEW JERSEY. .DAY ONE...TODAY AND TONIGHT. THERE IS A MODERATE RISK OF RIP CURRENTS TODAY. CONDITIONS MAY IMPROVE DURING THE AFTERNOON. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. RAIN MAY BE HEAVY AT TIMES FROM WEDNESDAY INTO WEDNESDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
123 PM EDT TUE AUG 17 2010
DEZ003-004-171845-
DELAWARE BEACHES DE-INLAND SUSSEX DE-
123 PM EDT TUE AUG 17 2010
...STRONG THUNDERSTORMS WILL AFFECT EASTERN SUSSEX COUNTY...
AT 119 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
SCATTERED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 11 MILES
NORTHEAST OF GEORGETOWN TO 20 MILES SOUTHEAST OF GEORGETOWN...MOVING
EAST AT 10 MPH. THE THUNDERSTORMS WILL BE NEAR LONG NECK AROUND 145
PM...LEWES...MILLVILLE AROUND 200 PM...OCEAN VIEW AROUND 215
PM...SOUTH BETHANY AND REHOBOTH BEACH AROUND 230 PM.
WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THESE STORMS.
EXPECT INTENSE LIGHTNING TO START OCCURRING FROM THESE STORMS. IF ON
THE BEACH, PLEASE SEEK SHELTER IMMEDIATELY AT THE FIRST SIGN OF
THREATENING WEATHER. DO NOT SEEK SHELTER UNDER TREES WHEN LIGHTNING
THREATENS...MOVE INDOORS WHEN A THUNDERSTORM APPROACHES.
LAT...LON 3845 7520 3885 7526 3885 7522 3880 7516
3879 7511 3881 7509 3880 7507 3865 7505
3863 7506 3860 7504 3859 7505 3847 7503
3846 7503 3844 7505
TFGSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
129 PM EDT TUE AUG 17 2010
NJZ022-024>026-171830-
ATLANTIC NJ-ATLANTIC COASTAL CAPE MAY NJ-COASTAL ATLANTIC NJ-
COASTAL OCEAN NJ-
129 PM EDT TUE AUG 17 2010
...A STRONG THUNDERSTORM WILL AFFECT ATLANTIC...CAPE MAY AND
POSSIBLY EXTREME SOUTHERN OCEAN COUNTY...
AT 124 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
DEVELOPING STRONG THUNDERSTORM 7 MILES WEST OF ATLANTIC
CITY...MOVING EAST AT 10 MPH. THE THUNDERSTORM WILL BE NEAR MARGATE
CITY...PLEASANTVILLE AROUND 145 PM...VENTNOR CITY...ABSECON AROUND
200 PM...ATLANTIC CITY AROUND 215 PM AND BRIGANTINE AROUND 230 PM.
WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM.
EXPECT LIGHTNING TO START OCCURRING FROM THESE STORMS. IF ON THE
BEACH, PLEASE SEEK SHELTER IMMEDIATELY AT THE FIRST SIGN OF
THREATENING WEATHER. DO NOT SEEK SHELTER UNDER TREES WHEN LIGHTNING
THREATENS...MOVE INDOORS WHEN A THUNDERSTORM APPROACHES.
LAT...LON 3937 7440 3936 7440 3929 7452 3930 7454
3928 7455 3928 7464 3930 7458 3930 7464
3945 7467 3950 7440 3949 7436 3949 7432
3947 7429 3945 7429
TFGSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
242 PM EDT TUE AUG 17 2010
NJZ022-025-171945-
ATLANTIC NJ-COASTAL ATLANTIC NJ-
242 PM EDT TUE AUG 17 2010
...A STRONG THUNDERSTORM WILL AFFECT ATLANTIC COUNTY...
AT 238 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 6 MILES WEST OF ATLANTIC CITY...MOVING EAST AT 10
MPH. THE THUNDERSTORM WILL BE NEAR MARGATE CITY...LONGPORT AROUND 300
PM...VENTNOR CITY AROUND 315 PM...ATLANTIC CITY AROUND 330 PM AND
BRIGANTINE AROUND 345 PM.
VERY HEAVY RAIN WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO
POND ON ROADS. WIND GUSTS UP TO 40 MPH ARE POSSIBLE WITH THIS STORM.
EXPECT LIGHTNING FROM THIS STORM. DO NOT SEEK SHELTER UNDER TREES
WHEN LIGHTNING THREATENS...MOVE INDOORS WHEN A THUNDERSTORM
APPROACHES. PLEASE LEAVE THE BEACHES AT THE FIRST SIGN OF THREATENING
WEATHER.
LAT...LON 3942 7433 3938 7439 3935 7441 3929 7452
3930 7463 3928 7467 3944 7466 3945 7447
3946 7447 3945 7446 3946 7444 3945 7438
3946 7429
TFGThe Dover AFB radar (KDOX), 46 km away, was scanning. The volume nearest the first event began at 19:14 UTC.
1 flash flood. Local standard time, as filed.
Thunderstorms dropped a Doppler Radar estimated up to four inches of rain across extreme southeast Sussex County. This caused stream, field and poor drainage flooding.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Delaware in 2010Every state in 2010This day in weather historyWarnings in Delaware, August 2010
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 256732.