Surface heating and destabilization led to the development of thunderstorms on the afternoon of the 29th. With strong instability but weak shear and the lack of a lifting mechanism, most storms remained unorganized.
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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 PBZ wrote it up.
Surface heating and destabilization led to the development of thunderstorms on the afternoon of the 29th. With strong instability but weak shear and the lack of a lifting mechanism, most storms remained unorganized. However, a storm moving across Allegheny county produced wind gusts that brought down a few large trees on federal street where several people were tailgating before a concert.
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 Pittsburgh, PA wrote its last area forecast discussion before the first event at May 30, 12:50 PM EST, 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 150 PM EDT SAT MAY 30 2015 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL CONTINUE UNTIL THE PASSAGE OF A STRONG COLD FRONT LATE SUNDAY. COOLER WEATHER WILL SETTLE OVER THE REGION TO START THE WORK WEEK. && .NEAR TERM /THROUGH SUNDAY/... AS EXPECTED...SURFACE HEATING AND DESTABILIZATION IS SUPPORTING AN INCREASE IN CONVECTION COVERAGE THIS AFTERNOON. HOWEVER...WITHOUT THE PRESENCE OF A STRONG LIFTING MECHANISM AND WEAK SHEAR...THE ENVIRONMENT MAINLY SUPPORTS UNORGANIZED THUNDERSTORMS REMINISCENT OF LATE SUMMER. HOWEVER...WITH STEEPENING LOW LEVEL LAPSE RATES...ANY OUTFLOW BOUNDARIES COULD SUPPORT A STRONG STORM OR TWO THROUGH LATE AFTERNOON. THIS IS SUPPORTED BY THE SPC MARGINAL RISK TODAY. PWAT VALUES AROUND 1.60INCHES WILL ALSO SUPPORT BRIEF HEAVY DOWNPOURS BUT DO NOT EXPECT MUCH IN THE WAY OF FLOODING CONCERNS BEYOND POOR DRAINAGE FLOODING OR TRAINING STORMS. CONTINUED WITH SCATTERED T-STORM WORDING THROUGH THE AFTERNOON TO BETTER REFLECT COVERAGE. DIURNAL CONVECTION WILL DIMINISH WITH THE LOSS OF HEATING TONIGHT AS THE FRONT REMAINS WEST OF THE AREA. TEMPERATURES SHOULD STILL TREND ABOVE NORMAL SUNDAY MORNING AS THE VORT MAX SHIFTS NORTHWARD TO LAKE ERIE AND SW FLOW CONTINUES. WHILE THE SURFACE LOW WILL MOVE RIGHT ACROSS OHIO AND WESTERN PA ON SUNDAY...SUPPORTING THE LIKELY POPS IN THE FORECAST...THE BULK OF THE UPPER LEVEL SUPPORT AND MID LEVEL MOISTURE WILL REMAIN NORTH...SO QPF DOES NOT LOOK OVERLY IMPRESSIVE. THE ONLY EXCEPTION WOULD BE IN THE HIGHER TERRAIN WITH OROGRAPHIC ENHANCEMENT. PRECIPITATION AND CLOUD COVER SHOULD HOLD TEMPERATURES A BIT DOWN COMPARED TO TODAY...BUT ARE STILL FORECAST TO BE ABOVE SEASONAL AVERAGES. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... MODELS HAVE SLOWED THE COLD FRONTAL PASSAGE LATE SUNDAY...WITH IT NOW STALLED OVER THE RIDGES THROUGH MONDAY. HAVE INCREASED POPS OVER THE RIDGES TO REFLECT THIS MONDAY AFTERNOON. WHILE POINTS NORTH AND WEST OF THE RIDGES SHOULD GENERALLY REMAIN DRY...WILL MAINTAIN A SLIGHT CHANCE FOR THE EARLY PART OF THE PERIOD UP NORTH AS THE MID-LEVEL LOW DEPARTS TO THE NORTHEAST. COLD ADVECTION WILL KEEP STRATOCUMULUS ENTRENCHED ACROSS MUCH OF THE UPPER OHIO VALLEY KEEPING TEMPERATURES ON THE COOL SIDE MONDAY. SURFACE RIDGE WILL START TO SETTLE ACROSS THE GREAT LAKES TUESDAY BUT STALLED BOUNDARY COULD CONTINUE AT LEAST A SLIGHT CHANCE FOR A SHOWER OVER THE HIGHER TERRAIN...WITH FOCUS EAST OF THE APPALACHIANS. TEMPERATURES SHOULD BEGIN TO MODERATE TO NEAR NORMAL ON TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... SURFACE HIGH PRESSURE WILL BRING DRY AND SEASONAL CONDITIONS MID WEEK. A WARMING TREND INTO NEXT WEEKEND AS HEIGHTS BUILD ALOFT. INCREASING DEEP MOISTURE AND AN APPROACHING COLD FRONT WILL BRING THUNDERSTORM CHANCES LATER FRIDAY AND SATURDAY. OVERALL CLOSE TO LATEST WPC PROGS. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... SCATTERED SHOWERS AND STORMS WILL BRING MVFR AT TIMES TO PORTS INTO THE EARLY EVENING...WITH BRIEF IFR POSSIBLE. LACK OF DAYTIME HEATING WILL HELP DIMINISH SHOWERS TOWARD 00Z. THEN GENERAL VFR OVERNIGHT ALTHOUGH SOME MFVR FOG MAY DEVELOP BEFORE DAYBREAK...LEFT OUT OF TERMINALS FOR NOW. AS COLD FRONT SLOWLY SINKS SOUTH LATER TONIGHT AND SUNDAY INCREASING SHOWERS WITH MVFR CIGS AT TIMES. .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RESTRICTIONS WILL BE POSSIBLE WITH WITH A SLOW MOVING COLD FRONT AND LOW PRESSURE INTO MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PITTSBURGH PA 315 AM EDT SAT MAY 30 2015 MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023- 029-031-073>076-WVZ001>004-012-021>023-041-310715- GARRETT-TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON- JEFFERSON OH-MUSKINGUM-GUERNSEY-BELMONT-NOBLE-MONROE-MERCER-VENANGO- FOREST-LAWRENCE-BUTLER-CLARION-JEFFERSON PA-BEAVER-ALLEGHENY- ARMSTRONG-INDIANA-WASHINGTON-GREENE-WESTMORELAND-WESTMORELAND RIDGES- FAYETTE-FAYETTE RIDGES-HANCOCK-BROOKE-OHIO-MARSHALL-WETZEL-MARION- MONONGALIA-PRESTON-TUCKER- 315 AM EDT SAT MAY 30 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST CENTRAL OHIO...NORTHWEST PENNSYLVANIA...SOUTHWEST PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA...NORTHERN WEST VIRGINIA AND NORTHERN PANHANDLE OF WEST VIRGINIA. .DAY ONE...TODAY AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
The Pittsburgh radar (KPBZ), 20 km away, was scanning. The volume nearest the first event began at 18:06 UTC.
1 thunderstorm wind. Local standard time, as filed.
Local media and emergency management reported several large trees down on Federal street, one of which fell on a car in the North Shore of Pittsburgh. Two women in the vehicle were sent to the hospital.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2015Every state in 2015This day in weather historyWarnings in Pennsylvania, May 2015
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: 582661.