A very moist southerly flow originating from the Gulf of Mexico combined with a slow-moving low pressure system over the Upper Midwest and Great Lakes produced heavy rainfall (3-5+ inches) across southeastern Pennsylvania over a two-day period. Minor flood stages were exceeded on the Conestoga River at Lancaster and Swatara Creek at Hershey.
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 CTP wrote it up.
A very moist southerly flow originating from the Gulf of Mexico combined with a slow-moving low pressure system over the Upper Midwest and Great Lakes produced heavy rainfall (3-5+ inches) across southeastern Pennsylvania over a two-day period. Minor flood stages were exceeded on the Conestoga River at Lancaster and Swatara Creek at Hershey.
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 State College, PA wrote its last area forecast discussion before the first event at Apr 30, 10:29 PM EST, 1 hour 31 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1129 PM EDT WED APR 30 2014 .SYNOPSIS... A LARGE UPPER LEVEL LOW OVER THE NORTHERN PLAINS WILL MAKE SLOW EASTWARD PROGRESS INTO THE GREAT LAKES REGION BY TONIGHT. AT THE SURFACE...A COLD FRONT WILL ADVANCE ACROSS THE APPALACHIANS BY THIS EVENING...AND THEN CONTINUE TO MOVE SLOWLY OFF THE EAST COAST OVERNIGHT. DEEP LOW LEVEL MOISTURE TRANSPORTED NORTHWARD FROM THE GULF OF MEXICO AHEAD OF THE COLD FRONT WILL SUPPORT WIDESPREAD MODERATE TO HEAVY RAINFALL THROUGH TONIGHT. FLOOD WATCHES REMAIN IN EFFECT FOR SOUTHEASTERN PORTIONS OF THE KEYSTONE STATE THROUGH THURSDAY MORNING. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... BACK EDGE OF DEEP LAYER MOISTURE FINALLY CLEARING MY EASTERN COUNTIES AFTER BRINGING ANOTHER 1+ INCHES OF RAIN TO WATER LOGGED AREAS OF ADAMS/YORK/LANCASTER COUNTIES...AS WELL AS DAUPHIN AND LEBANON AND PARTS OF SCHUYLKILL FOR GOOD MEASURE. EXCESSIVE RUNOFF CONTINUES AND WIDESPREAD ROAD CLOSURES WILL CONTINUE FOR SEVERAL MORE HOURS OVER THESE AREAS...AND WARNINGS REMAIN IN EFFECT THROUGH 145 AM/200 AM EDT. MEANWHILE...COLD FRONT IS APPROACHING THE CENTRAL MOUNTAINS FROM THE WEST AS SLOW MOVING UPPER LOW CENTER OVER THE UPPER MIDWEST CONTINUES TO THROW SPOKES OF VORTICITY TOWARDS THE OHIO VALLEY. ADDITIONAL QUARTER INCH TO LOCALLY HALF INCH (UPPER CEILING) AMOUNTS MAY BE FOUND FROM THE WEST CENTRAL TO THE NORTHWEST MOUNTAINS. SHOWERS WILL DIMINISH FROM WEST TO EAST AFTER MIDNIGHT AS THE COLD FRONT PROGRESSES EASTWARD. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... THE CLOSED H5 LOW LIFTS NEWD ACROSS THE GREAT LAKES INTO THE ST. LAWRENCE VALLEY ON DAY 2. MODEL DATA SUPPORTS SCATTERED SHOWER ACTIVITY WITH LGT AMTS IN MUCH DRIER CYCLONIC FLOW REGIME. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... UPPER LOW RESPONSIBLE FOR RAINY CONDITIONS THIS MIDWEEK WILL SLIDE NE ALONG THE ST LAWRENCE SEAWAY FRI INTO SAT...BUT BROAD TROUGH WILL REMAIN PERSISTENT OVER GREAT LAKES THROUGH THE WEEKEND. THIS WILL KEEP THE WEATHER SOMEWHAT UNSETTLED OVER PA...ESP NW HALF...AS WEAK WAVES SLIDING THROUGH MAIN FLOW COMBINED WITH LIMITED INSTABILITY DUE TO COOL AIR ALOFT TO KEEP MENTION OF SCT LIGHT SHOWERS IN THE FORECAST FOR SEVERAL DAYS. BEST PROB FOR MORE WIDESPREAD /BUT MAINLY LIGHT/ SHOWERS WILL BE SUNDAY AS A STRONGER WAVE/CLIPPER PUSHES THROUGH. TEMPS DURING THIS PERIOD WILL BE SEVERAL DEGREES BELOW NORMAL IN PERSISTENT W/NW FLOW...WITH BREEZY CONDITIONS ON FRI FOLLOWED BY AN EVEN STIFFER WIND SAT NIGHT INTO MON. ONCE THE CLIPPER SLIDES THROUGH...A BROAD RIDGE OVER CENTRAL U.S. WILL WORK ITS WAY EASTWARD...BRINGING A PERIOD OF MORE SETTLED WEATHER FOR MON NIGHT-WED WITH TEMPERATURES GRADUALLY MODIFYING BACK TO SEASONAL NORMALS. NEXT MIDWEEK COULD AGAIN BRING UNSETTLED WEATHER AS A WARM FRONT LIFTS THROUGH THE OHIO VALLEY...WITH SHOWERS LIKELY ALONG WITH A NOTICEABLE WARMUP FOR LATE WEEK. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... OCCLUSION IS ENTERING WESTERN PA AS OF 11PM/03Z. THE FRONT WILL MOVE SLOWLY EAST...KEEPING A MOIST SRLY FLOW OVER THE REGION ALONG WITH WIDESPREAD MVFR/IFR INTO THE OVERNIGHT WITH ON AND OFF SHOWERS. THE WIND WILL TURN TO A LIGHTLY DRIER SOUTHWESTERLY DIRECTION BEHIND THE FRONT. ALL TERMINALS WILL BEGIN TO IMPROVE LATE TONIGHT OR ON THURSDAY MORNING...WITH CONDITIONS IMPROVING TO VFR AT ALL SITES BY MID TO LATE MORNING THURSDAY. .OUTLOOK... .THU...IMPROVING CONDS AFTER AM LOW CIGS/RAIN. .FRI...NO SIG WX EXPECTED. .SAT-SUN...SCT SHRA POSS W/ CFROPA. .MON...NO SIG WX EXPECTED. && .HYDROLOGY... OBSERVED RAINFALL AMOUNTS OF 2 TO 3.5 INCHES SO FAR ACROSS LOWER SUSQUEHANNA VALLEY...WITH RADAR ESTIMATES SUGGESTING IN EXCESS OF 4-5" OVER EXTREME LANCASTER COUNTY. CONCERN FOR FLOODING/FLASH FLOODING CONTINUES THROUGH LATE TONIGHT. FLWS ISSUED LATE THIS AFTERNOON FOR SWATARA CREEK AT HARPER TAVERN...CONESTOGA RIVER AT LANCASTER...ADDITIONAL POINTS MAY BE ISSUED WITH THE MID EVENING UPDATE. && .CTP WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH THURSDAY MORNING FOR PAZ026>028-035-036- 049>053-056>059-063>066. && SYNOPSIS...GARTNER/STEINBUGL NEAR TERM...DEVOIR/GARTNER SHORT TERM...GARTNER/STEINBUGL LONG TERM...RXR AVIATION...LA CORTE HYDROLOGY...
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 117 PM EDT WED APR 30 2014 PAZ004>006-010>012-017>019-024-025-033-034-037-041-042-045-046- 011730- WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-CLEARFIELD- NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-SOMERSET-BEDFORD-TIOGA- NORTHERN LYCOMING-SULLIVAN-SOUTHERN CLINTON-SOUTHERN LYCOMING- 117 PM EDT WED APR 30 2014 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. HEAVY RAINFALL IS POSSIBLE THROUGH TONIGHT WHICH COULD LEAD TO FLOODING. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT FLOODING...PONDING OF WATER...RAINFALL MEASUREMENTS OR OTHER SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. PAZ026>028-035-036-049>053-056>059-063>066-011730- HUNTINGDON-MIFFLIN-JUNIATA-FULTON-FRANKLIN-UNION-SNYDER-MONTOUR- NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND- ADAMS-YORK-LANCASTER- 117 PM EDT WED APR 30 2014 ...FLOOD WATCH IN EFFECT THROUGH THURSDAY MORNING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. FLOOD WATCH. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. FLOOD WATCH. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT FLOODING...PONDING OF WATER...RAINFALL MEASUREMENTS OR OTHER SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. GARTNER
The national radar mosaic for the moment the first event began.
3 flood. Local standard time, as filed.
The Conestoga River at Lancaster reached minor flood stage during the predawn hours and crested at 11.63 ft. at 1100 AM EDT. The river fell below flood stage by the early afternoon.
The Swatara Creek at Hershey reached minor flood stage shortly after daybreak and crested at 7.08 ft. in the early afternoon. The creek fell below flood stage during the evening.
The Swatara Creek at Hershey reached minor flood stage shortly after daybreak and crested at 7.08 ft. in the early afternoon. The creek fell below flood stage during the evening.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2014Every state in 2014This day in weather historyWarnings in Pennsylvania, May 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: 510639, 510652, 510658.