A shortwave trough approached the Mid-Atlantic while a stationary boundary was across the region. Warm and moist conditions led to a unstable environment and showers and thunderstorms moved across the region.
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 LWX wrote it up.
A shortwave trough approached the Mid-Atlantic while a stationary boundary was across the region. Warm and moist conditions led to a unstable environment and showers and thunderstorms moved across the region. Some storms led to damaging winds.
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 Aug 21, 1:39 PM EST, 2 hours 53 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 239 PM EDT THU AUG 21 2014 .SYNOPSIS... A STATIONARY FRONT WILL WAVER ACROSS THE MID ATLANTIC AS RIPPLES OF LOW PRESSURE MOVE ALONG THE BOUNDARY. AN WILL TRAVERSE THE FRONT FRIDAY NIGHT...WHICH WILL PUSH IT SOUTH AS A COLD FRONT. HIGH PRESSURE FROM NEW ENGLAND WILL DOWN DOWN THE EAST COAST THIS WEEKEND. && .NEAR TERM /TONIGHT/... ISOLD TSTMS HV ALREADY DVLPD IN THE WRN PART OF THE FCST AREA IN THE SUMMERTIME AIR MASS. MAIN AREA OF PCPN HAS SPENT THE DAY TRAVERSING ACROSS IN INTO SRN OH ALONG A WARM FNT. THIS WL LKLY MOVE INTO THE WRN SXN OF THE CWA IN THE 4-5 PM TIMEFRAME...MOVG E OF THE MTNS THIS EVE. QUSTN WL BE IF IT CAN HOLD TOGETHER - IT ISN'T TOO IMPRESSIVE ATTM AND HRRR IS EVEN LESS SO AS IT TRIES TO MOVE TOWARDS THE METROS AFTR 00Z. REGARDING SVR THREAT - PULSE SVR WOULD BE WORST CASE SCENARIO. FOG LOOKS TO BE OF LESSER CONCERN TNGT THAN LAST NGT. LOWS IN THE 60S W OF I-95...L70S E. && .SHORT TERM /FRIDAY/... BNDRY RMNG IN THE AREA FRIDAY WL MOST LKLY SERVE AS A FOCUS FOR TSTMS. WL KEEP POPS IN CHC RANGE. AGN SVR THREAT LOOKS LOW - LO LVL WIND FIELD IS WEAK...CAPE IS NOT OVERLY IMPRESSIVE. FFG IS RLTVLY HIGH. HIGHS IN THE MU80S. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... AN UPPER LEVEL VORTICITY MAX WILL DIP THROUGH THE AREA OVERNIGHT FRIDAY...BRINGING ANOTHER BOUT OF ENHANCED RAINFALL. SURFACE HIGH PRESSURE CENTERED OVER NEW ENGLAND WILL RIDGE DOWN THE EAST COAST AS AN UPPER LEVEL SUBTROPICAL RIDGE BUILDS OVER THE EASTERN US. THE SURFACE RIDGE BUILDING DOWN INTO THE AREA WILL WORK WITH LOW PRESSURE OFF OF THE CAROLINA COAST TO BRING ONSHORE FLOW INTO THE MID-ATLANTIC BEGINNING SATURDAY MORNING. THE PRIMARY EFFECTS OF THE INCOMING MARINE AIRMASS WILL BE SEASONABLY COOL TEMPERATURES AND MOSTLY CLOUDY TO OVERCAST SKIES. EXPECT HIGHS ON SATURDAY...SUNDAY AND MONDAY TO ONLY BE IN THE MID TO UPPER 70S. HIGH PRESSURE WILL MOVE MORE OVERHEAD BY MONDAY NIGHT AND ONSHORE FLOW WILL MOSTLY BE SHUT OFF. LIGHT SOUTHERLY FLOW WILL BEGIN TO FILL INTO THE AREA TUESDAY...LEADING TO AN TREND TOWARD MORE SEASONABLE TEMPERATURES BY THE MIDDLE OF THE WEEK WITH HIGHS NEAR 80 ON TUESDAY AND IN THE MID 80S WEDNESDAY AND THURSDAY. HOWEVER...WITH A RATHER DRY PROFILE CONVECTION IS UNLIKELY TUESDAY OR WEDNESDAY. THE NEXT THREAT FOR STORMS ACROSS THE AREA SHOULD BE THURSDAY AS A COLD FRONT APPROACHES THE AREA. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... VFR CONDS XPCTD OUTSIDE OF ANY TSTMS. FOG MAY DVLP AT IAD/CHO/MRB AFTR MDNGT...BUT NOT XPCTD TO BE AS DENSE AS IT WAS THIS MRNG. TSTMS AGN PSBL FRI AFTN. PERIODS OF LOW CEILINGS ARE POSSIBLE AS AN UPPER LEVEL VORT MAX CROSSES THE AREA FRIDAY NIGHT AND THEN AGAIN OVER THE WEEKEND AND INTO EARLY NEXT WEEK AS A MARINE AIRMASS SETTLES INTO THE AREA. && .MARINE... WINDS XPCTD TO RMN BLO SCA VALUES TNGT/FRI. RW/TRW MAY OCCUR ON THE WATERS THIS EVE AND AGN FRI AFTN. A SMALL CRAFT ADVISORY MAY BE NECESSARY FOR THE WIDEST ZONES OF THE LOWER MARYLAND CHESAPEAKE BAY AND THE LOWER TIDAL POTOMAC SATURDAY AFTERNOON THROUGH SUNDAY NIGHT IN BREEZY EASTERLY FLOW. && .TIDES/COASTAL FLOODING... WATER LVLS ABOUT 3/4 FT ABV ASTRO NORMS. FRI MRNG TIDE WL BE HIGH...BUT AM NOT ANTICIPATING REACHING CRITERIA ATTM. HOWEVER... WE ARE WORKING ON A MARGIN OF INCHES. LATER SHIFTS WL MONITOR THE SITUATION. THERE COULD BE MORE NUISANCE ISSUES THIS WKND. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && PRODUCTS...WOODY!/CEB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 153 PM EDT THU AUG 21 2014 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 221500- CHESAPEAKE BAY NORTH OF POOLES ISLAND MD- CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT MD- CHESAPEAKE BAY FROM SANDY POINT TO NORTH BEACH MD- CHESAPEAKE BAY FROM NORTH BEACH TO DRUM POINT MD- CHESAPEAKE BAY FROM DRUM POINT MD TO SMITH POINT VA- TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD MD- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND MD- TIDAL POTOMAC FROM COBB ISLAND MD TO SMITH POINT VA- PATAPSCO RIVER INCLUDING BALTIMORE HARBOR- CHESTER RIVER TO QUEENSTOWN MD-EASTERN BAY- CHOPTANK RIVER TO CAMBRIDGE MD AND THE LITTLE CHOPTANK RIVER- PATUXENT RIVER TO BROOMES ISLAND MD- TANGIER SOUND AND THE INLAND WATERS SURROUNDING BLOODSWORTH ISLAND-DISTRICT OF COLUMBIA-NORTHERN BALTIMORE-HARFORD- SOUTHERN BALTIMORE-PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS- CALVERT-PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX- ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA- KING GEORGE- 153 PM EDT THU AUG 21 2014 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE MARYLAND PORTION OF THE CHESAPEAKE BAY...TIDAL POTOMAC RIVER...AND ADJACENT COUNTIES IN CENTRAL MARYLAND AND NORTHERN VIRGINIA AS WELL AS THE DISTRICT OF COLUMBIA. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS EVENING. A FEW OF THESE STORMS MAY BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS. STORMS THAT PRODUCE HEAVY RAINFALL COULD CAUSE LOCALIZED URBAN FLASH FLOODING. WATER LEVELS WILL REMAIN ABOVE AVERAGE ON THE TIDAL POTOMAC RIVER AND MARYLAND PORTION OF THE CHESAPEAKE BAY. NUISANCE TIDAL FLOODING WILL BE POSSIBLE WITH THE OVERNIGHT TIDE CYCLE. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THUNDERSTORMS...CAPABLE OF PRODUCING HEAVY RAIN...MAY DEVELOP LATE FRIDAY AND FRIDAY NIGHT. LOCALIZED FLOODING MAY RESULT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504- WVZ050>053-055-501>506-221500- WASHINGTON-FREDERICK MD-CARROLL-MONTGOMERY-HOWARD- EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-AUGUSTA- ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-NELSON- ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-LOUDOUN-ORANGE-CULPEPER- NORTHERN FAUQUIER-SOUTHERN FAUQUIER-WESTERN HIGHLAND- EASTERN HIGHLAND-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-HARDY- WESTERN GRANT-EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL- WESTERN PENDLETON-EASTERN PENDLETON- 153 PM EDT THU AUG 21 2014 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN WEST VIRGINIA... NORTHERN AND CENTRAL VIRGINIA...AND CENTRAL AND WESTERN MARYLAND WITH THE EXCEPTION OF GARRETT COUNTY. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP LATE TODAY INTO THIS EVENING. A FEW OF THESE STORMS MAY BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THUNDERSTORMS...CAPABLE OF PRODUCING HEAVY RAIN...MAY DEVELOP FRIDAY AFTERNOON CONTINUING INTO FRIDAY NIGHT. LOCALIZED FLOODING MAY RESULT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 346 PM EDT THU AUG 21 2014 ANZ538-MDZ005>007-010-011-014-212200- PATAPSCO RIVER INCLUDING BALTIMORE HARBOR-CARROLL- NORTHERN BALTIMORE-HARFORD-HOWARD-SOUTHERN BALTIMORE-ANNE ARUNDEL- INCLUDING THE CITIES OF...WESTMINSTER...COLUMBIA...BALTIMORE... ANNAPOLIS 346 PM EDT THU AUG 21 2014 AT 345 PM...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING AN AREA OF INTENSE THUNDERSTORMS OVER SOUTH-CENTRAL PENNSYLVANIA. THESE THUNDERSTORMS WERE MOVING SOUTHEAST AND ARE EXPECTED TO IMPACT THE GREATER BALTIMORE METRO AREA BETWEEN 6 AND 8 PM. THESE STORMS MAY BE CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS...FREQUENT CLOUD TO GROUND LIGHTNING AND VERY HEAVY RAIN. IN ADDITION...THERE IS A TORNADO THREAT. PEOPLE IN THE GREATER BALTIMORE METRO AREA SHOULD STAY TUNED FOR LATER STATEMENTS AND POSSIBLE WARNINGS THROUGH EARLY THIS EVENING. DH
The Dover AFB radar (KDOX), 115 km away, was scanning. The volume nearest the first event began at 21:34 UTC.
4 thunderstorm wind. Local standard time, as filed.
There were large tree branches down on Johnson Mill Road near Ady Road.
There were power lines and large tree branches down on 2300 Block of Ady Road.
There was a large tree branch down.
There was a tree down near the intersection of Carroll Road and Sparks Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maryland in 2014Every state in 2014This day in weather historyWarnings in Maryland, August 2014
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: 540095, 540096, 540097, 540098.