C. suburbs on the 19th.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 LWX wrote it up.
Two rounds of heavy rainfall occurred across the northern Washington D.C. suburbs on the 19th. The first batch hit during the pre-dawn hours and the next occurred during the evening. The 1st round of storms mainly affected Montgomery County and the second round affected Montgomery, Frederick, and Howard counties. In Montgomery County, Ready Creek in Brookeville overflowed its banks during the early morning storm. The remainder of the flooding occurred during the 2nd storm. In Rockville, a vehicle became stalled in high water at the intersection of Norbeck Road and Avery Road. Many roads were flooded in the Laytonsville area. In Kensington, Beach Drive was flooded. Cars were also stalled in high water in Gaithersburg. A total of 2.09 inches of rain was recorded in Potomac. In Frederick County, several small roads were flooded in Frederick. A handful of vehicles became stalled in high water, including those trying to cross West Patrick Street near West Frederick Middle School. Also in Frederick, a sinkhole that was 30 feet wide and 12 feet deep formed on New Design Road, forcing the closure of the busy thoroughfare. One person was injured when their car drove over the forming sinkhole. Later in the evening, a second sinkhole about 12 feet wide formed nearby. In Howard County, many roads were under water in the western portion of the county. In Prince George's County, 2.11 inches of rain was recorded at the Patuxent Filtration Plant in Laurel.
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 Baltimore/Washington wrote its last area forecast discussion before the first event at Jun 18, 8:45 PM EST, 5 hours 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 945 PM EDT WED JUN 18 2003 SCATTERED SHOWERS AND THUNDERSTORMS THAT DEVELOPED EARLIER TODAY GRADUALLY WINDING DOWN WITH THE LOSS OF HEATING FOR THE CENTRAL AND EASTERN COUNTIES AT THIS TIME. RADAR/SATELLITE COMPOSITE SHOWS A LARGE AREA OF RAIN WITH SCATTERED THUNDERSTORMS TO THE SOUTHWEST MOVING NORTHEAST. THIS WILL OVERSPREAD THE AREA LATER TONIGHT. CURRENT FORECAST HAS A GOOD HANDLE ON PENDING SITUATION. WILL REFRESH WORDING TO REMOVE CHANCE/EVENING WORDING AND CONTINUE WITH LIKELY POPS FOR THE REST OF TONIGHT. LATEST SURFACE OBS SHOW TEMPS AND WIND ON TRACK...SO ONLY COSMETIC CHANGES NEEDED TO THE FORECAST AT THIS TIME. WILL ALSO REFRESH SPS REGARDING THE RAINFALL POTENTIAL THROUGH THURSDAY./CPW ...AFTN DISCUSSION............. RADAR COMPOSITE SHOWS A LARGE AREA OF PRECIP OVER E TN MOVING INTO SW VA ATTM. THIS IS ASSOC WITH A SIGNIFICANT MID LVL SYSTEM SPINNING OVER N MISSISSIPPI WHICH IS PUSHING NE TOWARD CWA. BOTH GFS AND ETA SHOW THIS BATCH OF PRECIP AND ASSOC LIFT MOVING INTO CWA FROM SW TO NE BETWEEN 00Z AND 08Z. HAVE PUSHED POPS TO CATEGORICAL WHILE THIS BATCH OF PRECIP PASSES THRU. AROUND 12Z THIS MORNING 850MB LOW WILL BE DIRECTLY OVERHEAD...THEN EXITS CWA FROM SW TO NE DURING THE AFTERNOON. PRECIP WILL BECOME MORE SCT AS THE ENERGY PUSHES AWAY THU AFT. EXPECTING 0.50 TO 1.5 INCHES OF RAIN TO FALL OVER MOST OF CWA BETWEEN THIS EVE AND THU EVE. THIS IS BELOW 12 AND 24 HR FLOOD GUIDANCE BUT WITH HOW WET THE GROUND HAS BEEN WILL ISSUE SPECIAL WX STATEMENT TO TALK ABOUT PONDING OF WATER ON ROADS AND LOW LYING AREAS IN ADDITION TO SMALL CREEK/STREAM RISES BY TOMORROW DUE TO THE QPF. MMARGRAF THU NIGHT AND BEYOND...WHAT WAS ONCE A NICE HIGH PRES WEEKEND HAS DISINTEGRATED INTO A LARGE BOWLING BALL OF A CLOSED LOW OVER THE EAST. MODL RUNS PROGSVLY GET SLOWR WITH IT AND EXPCT...AND WILL FORECAST...THAT IT WILL BE SLOWR EXITING THAN THE 12Z GFS HAS. THAT WILL KEEP A FAIR AMNT OF CLDS AROUND AND POPS THRU THE WEEKEND. ALTHOUGH IT WILL NOT BE A WASHOUT WEEKEND...I THINK THE FORECAST WILL SPEAK FOR ITSELF. TEMPS WILL BE COOL WITH A N TO NE FLOW DEPNDNG ON THE STRENGTH OF ANY WAVES THAT DEVLP ON THE WEAK SFC FRONT TO OUR SE. CONSIDER THE CLIMATOLOGY OF THE PATTERN. FOR THE LAST SIX WEEKS SINCE MAY FIRST...A FULL NINETY PERCENT OF THE DAYS HAVE BEEN CLOUDY OR MOSTLY CLOUDY...SEVEN TENTHS OR MORE CLOUDY DURING THE DAYLIGHT HOURS. FURTHERMORE...ALMOST TWO THIRDS OF THE CALENDAR DAYS HAVE HAD MEASURABLE RAIN...NOT TO MENTION THE TRACE OF RAIN DAYS. IT/S HARD TO GO AGAINST THOSE NUMBERS ANYTIME THERE/S UNCERTAINTY IN THE FORECAST. AGAIN THERE/S NO STRONG SFC SYSTEM AT THIS POINT TO DRIVE ANY LARGE SYNOPTC SCALE RAIN...BUT THE SHR INSTAB OF HAVNG THIS LARGE COLD LOW OVR US WILL CERTAINLY BRING SHRA AT TIMES DURING THE WEEKEND. GRAD IMPRVE THINGS FOR MON AND LOOKS FAIR ATTM FOR TUE AND WED. NOT GOING TO GO BELOW A 24 POP THOUGH THRU THE FORECAST PERIOD. STRONG .LWX... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE.
DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042- 050>057-WVZ048>055-190900- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1130 AM EDT WED JUN 18 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR MARYLAND WEST OF THE CHESAPEAKE BAY AND EAST OF GARRETT COUNTY...THE DISTRICT OF COLUMBIA...NORTHERN VIRGINIA...THE NORTHERN AND CENTRAL SHENANDOAH VALLEY...AND THE EASTERN PANHANDLE OF WEST VIRGINIA. .DAY ONE...THIS AFTERNOON AND TONIGHT SHOWERS AND THUNDERSTORMS ARE EXPECTED TONIGHT. SOME OF THE RAINFALL COULD BE HEAVY ENOUGH TO PRODUCE LOCALIZED FLOODING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED. .DAYS TWO THROUGH SEVEN... SHOWERS AND THUNDERSTORMS ARE EXPECTED THURSDAY. SOME OF THE RAINFALL COULD BE HEAVY ENOUGH TO PRODUCE LOCALIZED FLOODING. HAZARDOUS WEATHER IS NOT EXPECTED SUNDAY THROUGH TUESDAY AT THIS TIME. MMARGRAF
DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042- 050>057-WVZ048>055-191000- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1030 PM EDT WED JUN 18 2003 ...MODERATE RAINFALL EXPECTED TONIGHT THROUGH THURSDAY AFTERNOON... AN AREA OF LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE MID ATLANTIC REGION LATE TONIGHT THROUGH EARLY THURSDAY. THIS WILL PRODUCE PERIODS OF LIGHT TO MODERATE RAIN TONIGHT THROUGH THURSDAY AFTERNOON. A TOTAL OF 0.5 TO 1.5 INCHES OF RAIN COULD FALL ACROSS THE AREA THROUGH THURSDAY AFTERNOON. THIS AMOUNT OF RAINFALL COULD CAUSE WATER TO POND ON ROADS. WATER MAY ALSO COLLECT IN DITCHES...UNDERPASSES...AND OTHER LOW LYING AREAS. IN ADDITION...SMALL STREAMS AND CREEKS MAY RISE TO BANKFULL BY THURSDAY AFTERNOON. THE RAINFALL IS NOT EXPECTED TO BE HEAVY ENOUGH TO CAUSE FLASH FLOODING OR RIVER FLOODING AT THIS TIME. HOWEVER...AREAS RIVERS MAY EXPERIENCE RISES TO THREE QUARTER BANKFULL BECAUSE OF THE SIGNIFICANT RUNOFF EXPECTED DUE TO THE WET GROUND CONDITIONS. A FLOOD WATCH WILL BE ISSUED IF THE AMOUNT OF EXPECTED PRECIPITATION INCREASES AND WIDESPREAD FLOODING BECOMES A THREAT. STAY TUNED TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA FOR THE LATEST INFORMATION ON THIS WEATHER EVENT. CPW
The Sterling radar (KLWX), 30 km away, was scanning. The volume nearest the first event began at 06:59 UTC.
4 flash flood, 1 heavy rain. Local standard time, as filed.
Ready Creek overflowed its banks. The time was estimated.
Several roads and basements were flooded. Two sinkholes closed New Design Road in Frederick.
Many roads were flooded.
Many roads were flooded.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maryland in 2003Every state in 2003This day in weather historyWarnings in Maryland, June 2003
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: 5370351, 5370352, 5370417, 5370415, 5370416.