A strong upper level disturbance moved into a moist atmosphere over the Lower Hudson Valley. It sparked scattered thunderstorms on August 16th.
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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 OKX wrote it up.
A strong upper level disturbance moved into a moist atmosphere over the Lower Hudson Valley. It sparked scattered thunderstorms on August 16th. A few of these storms became severe, and produced high winds and large hail.
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 New York, NY wrote its last area forecast discussion before the first event at Aug 16, 2:15 PM EST, 2 hours 55 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 315 PM EDT MON AUG 16 2004 .SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)... 500 HPA SHORTWAVE MOVING THROUGH THE AREA THIS AFTERNOON...MAY KEEP THE THREAT OF A SHOWER OR THUNDERSTORM THROUGH EARLY EVENING. MOST OF THE ACTION HAS REMAINED WELL NORTH AND WEST OF THE CITY. HOWEVER...WITH SOME SUN NOW BREAKING OUT FROM THE CITY WEST... INSTABILITY WILL INCREASE...TO AID AND ABET CONVECTION FOR THE REMAINED OF THE DAYLIGHT HOURS. OTHERWISE...A WEAK NORTHWEST TO NORTH DRYING FLOW SHOULD TAKE OVER OVERNIGHT AS WEAK HIGH PRESSURE BUILDS IN FROM THE GREAT LAKES. A TOUGH CALL WILL BE TO DETERMINE IF ENOUGH DRYING WILL OCCUR TO ERODE THE MOIST AIRMASS IN PLACE OVER THE REGION. IM THINKING THAT EVEN WITH A NORTHERLY COMPONENT...THAT THE MAGNITUDE OF THIS WIND WILL NOT BE ENOUGH TO ADVECT SUFFICIENT MOISTURE SWAY FROM THE ARE TO AVOID SOME PATCHY LATE NIGHT FOG OR STRATUS. HOWEVER...DO NOT THINK THAT CONDITIONS WILL GET TOO BAD...AS GRADUAL DRYING WILL BE A MITIGATING FACTOR. TUESDAY SHOULD BE THE FIRST NICE DRY DAY WEVE SEEN AROUND THESE PARTS IN QUITE A WHILE WITH WEAK HIGH PRESSURE TRAVERSING THE REGION...AND WEAK RIDGING FOLLOWING SUIT ALOFT. MODELS ALSO INDICATE A POCKET OF OF DRIER AIR FOR ALL LEVELS BUT THE BOUNDARY LAYER (ANOTHER REASON TO SUPPORT LOW CLOUDS/FOG OVERNIGHT AS LOW LEVELS NEVER REALLY DRY OUT) WILL MOVE ACROSS THE AREA ON TUESDAY. HOWEVER...THE FLOW WILL TURN MORE SOUTHWESTERLY TUESDAY NIGHT...AS WE SLOWLY START TO PUMP MORE SUB-TROPICAL MOISTURE BACK INTO THE REGION. && .LONG TERM (WEDNESDAY THROUGH MONDAY)... A COLD FRONT...AND ASSOCIATED MID-UPPER LEVEL TROUGH WILL MOVE INTO THE GREAT LAKES REGION ON WEDNESDAY AND THEN BEGIN TO STALL. THIS WILL KEEP US IN AN INCREASINGLY WARM AND MOIST REGIME THROUGH THE END OF THE WEEK. INCREASING MOISTURE IN THE SOUTHERLY FLOW AND DAYTIME HEATING WILL INCREASE INSTABILITY AND WILL AGAIN CARRY CHANCE PROBABILITY FOR SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON...MAINLY INLAND. THE AFOREMENTIONED FRONT FRONT WILL WASH OUT ON THURSDAY HAVING GOTTEN NO CLOSER THAN THE EASTERN GREAT LAKES. THE NEXT COLD FRONT APPROACHES BEHIND THE STAGNANT BOUNDARY...BUT WILL ALSO BE SLOW MOVING. AT THIS POINT THE MODELS INDICATE THAT THIS FRONT WILL SLOWLY PROGRESS EAST AND WILL CLEAR THE COAST BY LATE SUNDAY. THIS REPRESENTS A DELAY FROM PREVIOUS RUNS...AND LIKELY POINTS TOWARD A FUTURE SOLUTION THAT WILL SUGGEST THAT IT WILL NOT CLEANLY TRAVERSE THE REGION IN A MANNER SIMILAR TO RECENT ATTEMPTS. HOWEVER...WILL NOT JUMP AHEAD OF OURSELVES AT THIS TIME. WE WILL SHIFT THE PASSAGE OF THIS FRONT BACK ABOUT 12 HOURS IN LINE WITH 16/12Z GFS...AND ANTICIPATE FUTURE DELAYS WITH RESPECT TO THIS FEATURE IN THE DAYS TO COME. WHILE THE PERIOD FROM THE MIDDLE OF THE WEEK THROUGH THE WEEKEND IS EXPECTED TO REMAIN UNSETTLED...THERE ARE NO STRONG FEATURES TO SUGGEST THE THREAT OF SIGNIFICANT RAINFALL. THE STRONGEST FOCUSING MECHANISM WILL BE THE FRONT THAT MOVES THROUGH ON SUNDAY. HOWEVER... THAT IS STILL A WAYS OFF AND THIS FORECASTER HAS SOME DOUBT ON THAT OCCURRENCE AS THE GFS PAST 120 HOURS STILL DEPICTS MID-UPPER LEVEL FLOW THAT IS CLOSER TO PARALLEL TO THE FRONTAL BOUNDARY THAN IT IS PERPENDICULAR. && .AVIATION...BACK EDGE OF WIDESPREAD PRECIPITATION MOVING THROUGH EASTERN LI/CT. CIGS GENERALLY MVFR AND VSBY NOT A PROBLEM ACROSS THE AREA. SHORTWAVE MOVING THROUGH THE AREA THIS AFTERNOON/EVENING ACCOMPANIED BY ABUNDANT MOISTURE WILL TRIGGER SCATTERED SHOWERS AND TSTMS MAINLY NORTH AND WEST OF NYC TERMINALS. VIS SATELLITE SHOWS BUILDING CU AND RADAR INDICATES SHOWERS POPPING IN NE NJ. AXIS OF INSTABILITY LIES ABOUT 40SM NW OF KALB DOWN TO KSEG. LIMITED HEATING WILL SUPPRESS WIDESPREAD TSTM ACTIVITY AND THINGS SHOULD QUIET DOWN AFTER SUNSET. LOW LEVEL INVERSION SETS UP OVERNIGHT WITH LIGHT WINDS WHICH LOOKS LIKE IT WILL CAUSE LOW STRATUS AND PATCHY FOG DEVELOPMENT. CONDITIONS WILL IMPROVE TO VFR BETWEEN 13Z AND 15Z TUE. && .MARINE... WEAK WAVE JUST SE OF THE WATERS WILL PASS NE OVERNIGHT. BUOY 025 WINDS HAVE PICKED UP IN THE VICINITY OF THE WAVE TO 20G25KT THIS LAST HOUR AND EXPECT THESE CONDITIONS TO PULL EAST TO 44017 THIS EVENING GIVEN TRACK OF SYSTEM. GIVEN THE SHORT DURATION AND MARGINAL NATURE OF THIS EVENT WILL NOT PUT UP SCA. SEAS SHOULD REMAIN JUST BELOW SCA. HIGH PRESSURE BUILDS OVER THE WATERS OVERNIGHT WITH WINDS RELAXING. SURFACE RIDGE PUSHES EAST OF THE AREA BY WEDNESDAY AND THEN REMAINS THROUGH THE END OF THE WEEK WITH SOUTHERLY FLOW AND FETCH...BUT SEAS SHOULD REMAIN JUST BELOW SCA THROUGH THE PERIOD. COLD FRONT APPROACHES FOR THE WEEKEND...WITH A TIGHTENING S/SW GRADIENT AND SEAS ON THE OCEAN BUILDING TO MINIMAL SCA ON SATURDAY. && .HYDROLOGY... DRY WEATHER TONIGHT THROUGH WEDNESDAY MORNING THEN SCATTERED THUNDERSTORMS IN THE AFTERNOON AND AGAIN THURSDAY AFTERNOON. COULD SEE UP TO A QUARTER INCH EACH DAY WITH LOCALIZED HIGHER AMOUNTS. AGAIN NO PROBLEMS ANTICIPATED WITH RELATIVELY LIGHT BASIN AVERAGE QPFS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NJ...NONE. NY...NONE. MARINE...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE UPTON NY 405 AM EDT MON AUG 16 2004 CTZ005>012-NJZ002>006-011-NYZ067>081-171000- BERGEN NJ-BRONX NY-EASTERN PASSAIC NJ-ESSEX NJ-HUDSON NJ- KINGS (BROOKLYN) NY-NASSAU NY-NEW YORK (MANHATTAN) NY- NORTHEAST SUFFOLK NY-NORTHERN FAIRFIELD CT-NORTHERN MIDDLESEX CT- NORTHERN NEW HAVEN CT-NORTHERN NEW LONDON CT-NORTHERN WESTCHESTER NY- NORTHWEST SUFFOLK NY-ORANGE NY-PUTNAM NY-QUEENS NY- RICHMOND (STATEN IS.) NY-ROCKLAND NY-SOUTHEAST SUFFOLK NY- SOUTHERN FAIRFIELD CT-SOUTHERN MIDDLESEX CT-SOUTHERN NEW HAVEN CT- SOUTHERN NEW LONDON CT-SOUTHERN WESTCHESTER NY-SOUTHWEST SUFFOLK NY- UNION NJ-WESTERN PASSAIC NJ- 405 AM EDT MON AUG 16 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEASTERN NEW YORK... NORTHEASTERN NEW JERSEY AND SOUTHERN CONNECTICUT. .DAY ONE...TODAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN... NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE UPTON NY 444 PM EDT MON AUG 16 2004 NYZ067-162145- ORANGE- 444 PM EDT MON AUG 16 2004 AT 444 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR IN UPTON NY HAS DETECTED AN AREA OF THUNDERSTORMS 9 MILES NORTHEAST OF CUDDEBACKVILLE...MOVING SOUTHEAST AT 10 MPH. BASED ON THIS MOVEMENT...THE THUNDERSTORM SHOULD BE IN THE VICINITY OF... CUDDEBACKVILLE AROUND 500 PM... FINCHVILLE...PORT JERVIS AROUND 540 PM... OTISVILLE AROUND 545 PM... DANGEROUS CLOUD TO GROUND LIGHTNING...TORRENTIAL RAINS...HAIL UP TO ONE HALF INCH IN DIAMETER...AND WIND GUSTS UP TO 35 MPH CAN BE EXPECTED WITH THESE STORMS. HEAVY RAINS FROM THIS SLOW MOVING THUNDERSTORM MAY FLOOD LOW LYING AND POOR DRAINAGE AREAS SUCH AS DITCHES AND UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS.
The Brookhaven radar (KOKX), 121 km away, was scanning. The volume nearest the first event began at 22:11 UTC.
2 thunderstorm wind, 1 hail, 1 lightning. Local standard time, as filed.
Trees were downed. A power pole was downed, which caused power outages.
A house was hit by lightning in Slate Hill.
A large tree limb was downed, which partially blocked a road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in New York in 2004Every state in 2004This day in weather historyWarnings in New York, August 2004
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: 5418915, 5418914, 5418916, 5418917.