A combination of a passing pre-frontal trough and an approaching cold front spawned an isolated severe thunderstorm in Fairfield 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 OKX wrote it up.
A combination of a passing pre-frontal trough and an approaching cold front spawned an isolated severe thunderstorm in Fairfield 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 New York, NY wrote its last area forecast discussion before the first event at Aug 10, 8:03 PM EST, 22 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 903 PM EDT MON AUG 10 2009 .SYNOPSIS... A WARM FRONT WILL REMAIN NORTH OF THE AREA TONIGHT AS A LOW PRESSURE TROUGH DEVELOPS IN THE REGION. A COLD FRONT WILL PASSES OVER THE AREA TUESDAY AFTERNOON INTO TUESDAY NIGHT. HIGH PRESSURE BUILDS IN BEHIND THE FRONT FOR WEDNESDAY AND THURSDAY. A WAVE OF LOW PRESSURE MAY DEVELOP AND IMPACT THE REGION OF THE WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... FCST UPDATED TO EXPAND SVR WATCH TO CNTRL CT. TSTMS OVER THE LWR HUDSON VALLEY HAVE A HISTORY OF PRODUCING DAMAGING WINDS AND CONTINUE TO TRACK EWD AT 20-25KT. OUTFLOW BOUNDARY FROM THIS CONVECTION NOW APPROACHING KNYC WITH SOME WIND GUSTS POSSIBLE. POTENTIAL FOR CELLS TO INITIATE ALONG THIS BOUNDARY. AMS STILL UNSTABLE S AND E OF THIS CONVECTION WITH OVER 2K J/KG CAPE. SVR POTENTIAL EXISTS ACROSS NL COUNTY IN CT AND ERN SUFFOLK ON LI IF STORMS MAINTAIN. WEAKENING TSTMS OVER CNTRL PA REACH THE CWA 4-5Z AND SPREAD E OVERNIGHT. SCT TSTMS INCLUDED IN FCST. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... THE REGION WILL REMAIN UNDER A RATHER WARM AIRMASS ON TUESDAY...UNTIL A COLD FRONT PUSHES ACROSS THE CWA LATE THE DAY/EVENING ON TUESDAY. THE NEED FOR A HEAT ADVISORY WILL BE CLOSELY MONITORED OVER THE NEXT 6 TO 12 HOURS. TEMPERATURES ON TUESDAY ARE EXPECTED TO REACH THE UPPER 80S AND LOWER 90S ACROSS THE TRI-STATE AREA...ALONG WITH DEW POINTS IN THE MIDDLE TO UPPER 60S. SPECIFICALLY...TEMPERATURES IN NYC ARE FORECAST TO REACH 89 AT CENTRAL PARK...91 AT LGA AND 90 AT JFK. HEAT INDEX VALUES ARE EXPECTED REACH ANYWHERE FROM 90 TO 93 DEGREES. DESPITE HEAT INDEX VALUES REACHING 96 TODAY AT CENTRAL PARK AND JFK...AND 95 AT LGA...A HEAT ADVISORY WILL NOT BE POSTED AT THIS TIME...SINCE CONFIDENCE IS MODERATE TO HIGH THAT THE HEAT INDEX WILL NOT REACH 95 DEGREES. AS A COLD FRONT APPROACHES FROM THE WEST AND A WARM AIRMASS OVER THE TRI-STATE...SHOWERS AND THUNDERSTORMS WILL RETURN TO THE FORECAST. SOME STORMS MAY BE ON THE STRONG SIDE WITH DECENT CAPES AND STEEPENING LOWER LEVEL LAPSE RATES DEVELOPING. AS A RESULT...THE STORM PREDICTION CENTER HAS THE ENTIRE CWA UNDER A SLIGHT RISK FOR TOMORROW. ANY SHOWERS AND STORMS COME TO AN END TUESDAY EVENING AS FRONT CLEARS THE CWA. HIGH PRESSURE BUILDS IN BEHIND THE FRONT ON WEDNESDAY...BUT WEAKLY AS AN UPPER TROF AXIS APPROACHES. WOULD LIKE TO SEE A BETTER TRIGGER BEFORE PUTTING ANY SHOWER CHANCES IN THE FORECAST. MET/MAV MOS BLEND LOOKED GOOD. TROF AXIS ALOFT DEPARTS TO THE EAST ON THURSDAY. WEAK HIGH PRESSURE STILL AT THE SURFACE. WILL GO WITH A DRY FORECAST AGAIN WITH NEAR-NORMAL TEMPS. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE DOMINATES INITIALLY FROM THU NIGHT THROUGH SAT AFTERNOON...BUT THEN FORECAST UNCERTAINTIES CREEP IN REGARDING THE FUTURE EVOLUTION OF A WEAK MID LEVEL CUTOFF LOW FORECAST BY THE NUMERICAL GUIDANCE TO PINCH OFF FROM THE WESTERLIES IN THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS THU-FRI...AND THEN RETURN SLOWLY NORTHEAST TOWARD THE MID ATLANTIC REGION THIS WEEKEND. THE LAST TWO RUNS OF THE OPERATIONAL GFS HAVE BEEN QUITE AMPLIFIED WITH THIS FEATURE AND SUGGEST QUITE A DOUSING OF RAIN COULD BE POSSIBLE. THE 12Z GEFS MEAN IS A LITTLE MORE SUPPRESSED...AND THE LAST TWO RUNS OF THE ECWMF SHOW A COMPLETELY SUPPRESSED SOLUTION AND CONTINUED FAIR WX INTO EARLY NEXT WEEK. ECMWF HANDLING OF THESE TYPES OF CUTOFF LOWS CAN SOMETIMES BE ERROR PRONE...SO HAVE NOT PUT FULL STOCK IN ITS SOLUTION...AND WILL BE CARRYING SLIGHT CHANCE POP FROM SAT NIGHT AND BEYOND. TEMPS SHOULD BE NEAR NORMAL THROUGH THE PERIOD. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... MAIN TSTM ACTIVITY N OF THE METRO THIS EVE. TSTMS OVER CNTRL PA REACH THE METRO NEAR 4Z SO TEMPO TSRA FOR THAT PERIOD. VFR OUTSIDE OF TSTMS. WSW WINDS BLW 10KT OUTSIDE OF TSTMS. SEA BREEZE KJFK TO VEER TO SYNOPTIC FLOW QUICKLY THIS EVE. LINGERING LLVL MOISTURE FROM TSTMS MAY RESULT IN MRNG STRATUS. WENT WITH SCT GROUP TO HINT AT THIS POSSIBILITY. PATCHY MVFR WILL BE POSSIBLE. AFT MRNG LOW CLOUDS MIX OUT...AFTN CB/S WITH TSTMS POSSIBLE INTO THE EVE WITH AN APPROACHING COLD FRONT. STRATUS MAY LINGER AT KGON THRU THE DAY...FOR NOW KEPT CIGS JUST ABV MVFR TIL WITH MOISTURE HOVERING AROUND 3-4K FT. ELSEWHERE...VRF OUTSIDE OF TSTMS. OUTLOOK FOR 06Z WED THROUGH SAT... MVRR POSSIBLE IN SCT TSTMS WED WITH UPR LVL DISTURBANCE. PERIODS OF MVFR POSSIBLE...ESPECIALLY IN THE EARLY MRNG HRS...THU-FRI WITH ELY FLOW. VFR SAT ATTM. && .MARINE... SVR TSTM WATCH FOR THE SOUND TIL 11 PM. STRONG WINDS AND HVY RA THE MAIN THREATS. SUB SCA CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT TO MODERATE SW FLOW EXPECTED TONIGHT INTO TUES AHEAD OF COLD FRONT...WITH LIMITED MIXING DURING THE DAY. COLD FRONT COMES THROUGH TUES NIGHT WITH OFFSHORE FLOW IN ITS WAKE. HIGH PRESSURE BUILDING OVER THE WATERS MID-WEEK AND WEAK GRADIENT IN EXISTENCE KEEP WINDS AND SEAS BELOW SCA. && .HYDROLOGY... SCATTERED THUNDERSTORMS THIS EVENING WITH GENERALLY QUARTER TO ONE HALF INCH...BUT LOCALLY UP TO AN INCH OF RAINFALL. CONVECTION ON TUESDAY SHOULD BE MORE WIDESPREAD WITH LOCALLY HEAVY RAINFALL UP TO ONE INCH. MINOR URBANIZED FLOODING AND SMALL STREAM FLOODING WILL BE POSSIBLE BOTH DAYS. DRY WEATHER RETURNS LATER TUESDAY NIGHT...THEN MAINLY DRY THROUGH FRIDAY. THERE WILL BE A SLIGHT CHANCE OF A SIGNIFICANT RAINFALL OVER THE WEEKEND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && SYNOPSIS... NEAR TERM...JMC SHORT TERM... LONG TERM... AVIATION...JMC MARINE... HYDROLOGY...
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE NEW YORK NY 848 PM EDT MON AUG 10 2009 ANZ338-340-345-350-353-355-CTZ008-012-NJZ005-006-011-NYZ072>081- 120100- NEW YORK HARBOR-PECONIC AND GARDINERS BAYS- SOUTH SHORE BAYS FROM JONES INLET THROUGH SHINNECOCK BAY- MORICHES INLET NY TO MONTAUK POINT NY OUT 20 NM- FIRE ISLAND INLET NY TO MORICHES INLET NY OUT 20 NM- SANDY HOOK NJ TO FIRE ISLAND INLET NY OUT 20 NM-NORTHERN NEW LONDON- SOUTHERN NEW LONDON-ESSEX-HUDSON-UNION-NEW YORK (MANHATTAN)-BRONX- RICHMOND (STATEN ISLAND)-KINGS (BROOKLYN)-QUEENS-NASSAU- NORTHWESTERN SUFFOLK-NORTHEASTERN SUFFOLK-SOUTHWESTERN SUFFOLK- SOUTHEASTERN SUFFOLK- 848 PM EDT MON AUG 10 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS...SOUTHERN CONNECTICUT...NORTHEAST NEW JERSEY AND SOUTHEAST NEW YORK. .DAY ONE...TONIGHT. THUNDERSTORMS THIS EVENING MAY BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND MINOR URBAN AND POOR DRAINAGE FLOODING. SEVERE THUNDERSTORM WATCHES JUST TO THE NORTH AND WEST COULD EVENTUALLY BE EXPANDED INTO THE AREA. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THUNDERSTORMS ON TUESDAY MAY BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && THIS HAZARDOUS WEATHER OUTLOOK PROVIDES A SUMMARY OF POTENTIAL WIDESPREAD HAZARDOUS WEATHER EVENTS THAT MAY REACH NWS WARNING CRITERIA. MOST LONG FUSED NWS WATCHES...WARNINGS AND ADVISORIES IN EFFECT ARE HIGHLIGHTED. PLEASE REFER TO THE LATEST NWS FORECASTS FOR WEATHER NOT MEETING NWS WARNING CRITERIA. ANZ330-335-CTZ005>007-009>011-NJZ002>004-NYZ067>071-120100- LONG ISLAND SOUND EAST OF NEW HAVEN CT/PORT JEFFERSON NY- LONG ISLAND SOUND WEST OF NEW HAVEN CT/PORT JEFFERSON NY- NORTHERN FAIRFIELD-NORTHERN NEW HAVEN-NORTHERN MIDDLESEX- SOUTHERN FAIRFIELD-SOUTHERN NEW HAVEN-SOUTHERN MIDDLESEX- WESTERN PASSAIC-BERGEN-EASTERN PASSAIC-ORANGE-PUTNAM-ROCKLAND- NORTHERN WESTCHESTER-SOUTHERN WESTCHESTER- 848 PM EDT MON AUG 10 2009 ...SEVERE THUNDERSTORM WATCH 696 IN EFFECT UNTIL 11 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS...SOUTHERN CONNECTICUT...NORTHEAST NEW JERSEY AND SOUTHEAST NEW YORK. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. SEVERE THUNDERSTORM WATCH. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THUNDERSTORMS ON TUESDAY MAY BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. && THIS HAZARDOUS WEATHER OUTLOOK PROVIDES A SUMMARY OF POTENTIAL WIDESPREAD HAZARDOUS WEATHER EVENTS THAT MAY REACH NWS WARNING CRITERIA. MOST LONG FUSED NWS WATCHES...WARNINGS AND ADVISORIES IN EFFECT ARE HIGHLIGHTED. PLEASE REFER TO THE LATEST NWS FORECASTS FOR WEATHER NOT MEETING NWS WARNING CRITERIA. JMC
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE NEW YORK NY 636 PM EDT MON AUG 10 2009 NYZ067-102330- WESTERN ORANGE- 636 PM EDT MON AUG 10 2009 ...DEVELOPING THUNDERSTORMS WILL IMPACT WESTERN ORANGE COUNTY... AT 632 PM EDT...RADAR INDICATED THAT THUNDERSTORMS WERE DEVELOPING ALONG A LINE EXTENDING FROM 15 MILES SOUTHWEST OF HIGHLAND LAKE TO 9 MILES WEST OF MILFORD TO 9 MILES SOUTHEAST OF MILFORD...AND MOVING EAST AT 30 MPH. BASED ON THIS MOVEMENT...THESE STORMS WILL BE NEAR... UNIONVILLE BY 700 PM... WARWICK BY 710 PM... FLORIDA BY 720 PM... OTISVILLE BY 730 PM. PEOPLE IN ORANGE COUNTY...INCLUDING UNIONVILLE...PORT JERVIS... WARWICK...FLORIDA...OTISVILLE...MONROE...CHESTER...MIDDLETOWN... HARRIMAN AND GOSHEN...SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE WEATHER THREATEN. GOODMAN
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW YORK NY
815 PM EDT MON AUG 10 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0749 PM TSTM WND GST WARWICK 41.26N 74.36W
08/10/2009 M57.00 MPH ORANGE NY TRAINED SPOTTER
0803 PM TSTM WND GST 5 WNW MONTGOMERY 41.56N 74.32W
08/10/2009 M58.00 MPH ORANGE NY TRAINED SPOTTER
&&
JPSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE NEW YORK NY 848 PM EDT MON AUG 10 2009 NJZ002-003-NYZ071-110130- BERGEN-SOUTHERN WESTCHESTER-WESTERN PASSAIC- 848 PM EDT MON AUG 10 2009 ...STRONG THUNDERSTORMS WILL IMPACT NORTHERN BERGEN...PASSAIC AND WESTCHESTER COUNTIES... AT 847 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR WEST MILFORD...AND MOVING EAST AT 35 MPH. THIS STORM WILL BE... 6 MILES NORTH OF BLOOMINGDALE BY 855 PM. NEAR RINGWOOD BY 900 PM. NEAR RAMSEY BY 915 PM. 6 MILES NORTH OF NORWOOD BY 930 PM. PEOPLE IN NORTHERN BERGEN...PASSAIC AND SOUTHERN WESTCHESTER COUNTIES...INCLUDING WEST MILFORD...RINGWOOD AND RAMSEY...SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE WEATHER THREATEN. WINDS UP TO 40 MPH ARE EXPECTED WITH THIS STORM. LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. MOVE TO SAFE SHELTER IMMEDIATELY. GOODMAN
The Brookhaven radar (KOKX), 66 km away, was scanning. The volume nearest the first event began at 01:24 UTC.
2 thunderstorm wind, 1 lightning. Local standard time, as filed.
An estimated wind gust of 65 mph was reported by a trained spotter in Greenwich.
At least 42 trees and large branches were downed in Greenwich.
Lightning strikes resulted in two fires in Greenwich. The fires were quickly put out.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Connecticut in 2009Every state in 2009This day in weather historyWarnings in Connecticut, August 2009
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: 195130, 195277, 195285.