Flash Flood, Mercer
- When
- May 18, 8:58 AM EST to 2:08 PM EST
- Where
- Mercer County, Central Portion
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 40.283, -74.702 (the zone’s center; the record gives no point)
Flash Flood in New Jersey, May 18, 2002
m. m.
Where it happened
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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.
What happened
The episode as NWS PHI wrote it up.
Around two inches of rain fell in the Assunpink Basin, mainly between 5 a.m. and 930 a.m. EDT. This was enough heavy rain in a short period of time to cause flooding along the Assunpink Creek in Mercer County. The creek reached its 7 foot flood stage at 958 a.m. EDT, crested at 7.45 feet at 1 p.m. EDT and was back within bankfull at 308 p.m. EDT. No serious damage or injuries were reported.
What forecasters said that day
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 May 18, 2:53 AM EST, 6 hours 5 minutes earlier.
Area forecast discussion, May 18, 2:53 AM EST, 6 hours 5 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 353 AM EDT SAT MAY 18 2002 FNTL ZN WAVERING ABT DLMARVA AS SFC LO IN WRN VA HEADS TWD NJ CST ERLY THIS MRNG. THIS LOW SHUD CONT TO MOV NE AND BE IN NEW ENGLAND LT TDA. PRECIP OVERNGT APPRS TO BE QUITE PLENTIFUL ACRS PTNS NE PA AND NW NJ DOWN INTO PTNS OF SE PA AND CNTRL NJ. SOME THUNDER EVEN DEVELOPED ARND PHL AND IN PTNS OF GLOUCESTER AND CAMDEN CTYS OF NJ ARND MDNGT. FURTHER S AND E SOME RN HAS FELL...BUT NOT CONTINUOUS. NE WNDS BRIEFLY PUSHED INTO SUSSEX CTY DE BUT SW WNDS NOW RULE AS FNTL ZN APPRS TO STAY N OF THIS AREA. WL HAVE TO WAIT UNTIL CD FNT MOVS ACRS AREA LT MRNG OR ERLY AFTN. AFTER THAT...HI PRES FRM MDWEST WL TRY TO BLD INTO AREA...HOWEVER H5 LO WL PIVOT SW ACRS ERN CANADA AND BRING S/W TROF ACRS AREA MON AFTN AND MON NGT. THIS SHUD HAVE SOME REALLY COOL AIR WITH THIS FEATURE WHEN IT GOES THROUGH. ON MARINE...SML CRFT ADVSRY CONTD FOR CST AND BAY. FCSTID = 14 MPO 50 35 54 38 / 60 0 0 0 ABE 54 38 58 40 / 60 0 0 0 RDG 54 38 58 40 / 60 0 0 0 PHL 62 45 61 45 / 60 0 0 0 12N 50 35 54 38 / 60 0 0 0 SMQ 57 40 60 42 / 60 0 0 0 TTN 57 40 60 42 / 60 0 0 0 MIV 62 43 61 45 / 60 0 0 0 ACY 64 46 61 48 / 60 0 0 0 ILG 61 42 61 43 / 60 0 0 0 DOV 62 44 61 44 / 60 0 0 0 GED 66 46 61 47 / 60 0 0 0 ESN 62 44 61 44 / 60 0 0 0 .PHI... DE...NONE. MD...NONE. NJ...NONE. PA...NONE. MARINE...SML CRFT ADVSRY CST AND BAY ANZ430-431-450>455. JWH
The radar
The Philadelphia radar (KDIX), 45 km away, was scanning. The volume nearest the first event began at 13:59 UTC.
Event by event
1 flash flood. Local standard time, as filed.
What these are
- Flash Flood
- Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Cold in Georgia, May 18 to 23, 2002
- Tornado and Damaging Winds in Maryland, May 18, 2002
- Damaging Winds in Virginia, May 18, 2002
- Marine Thunderstorm Winds and Waterspouts in North Atlantic Coastal Waters, May 18, 2002
- Marine Thunderstorm Winds in North Atlantic Coastal Waters, May 18, 2002
- Heavy Snow in New Hampshire, May 18, 2002
- Damaging Winds in South Carolina, May 18, 2002
- Winter Storm in New York, May 18, 2002
- Marine Thunderstorm Winds in North Atlantic Coastal Waters, May 18, 2002
- Damaging Winds in Maryland, May 18, 2002
- Flooding in Kentucky, May 18 to 24, 2002
- Flood in Oklahoma, May 18, 2002
More
Every storm in New Jersey in 2002Every state in 2002This day in weather historyWarnings in New Jersey, May 2002
Sources
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: 5299972.