A broken line of storms developed over the Lower Susquehanna Valley ahead of an approaching cold front during the late morning and afternoon of April 9, 2020. These storms produced sporadic wind damage across Lancaster 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 CTP wrote it up.
A broken line of storms developed over the Lower Susquehanna Valley ahead of an approaching cold front during the late morning and afternoon of April 9, 2020. These storms produced sporadic wind damage across Lancaster 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 State College, PA wrote its last area forecast discussion before the first event at Apr 9, 6:21 AM EST, 4 hours 49 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 721 AM EDT Thu Apr 9 2020 .SYNOPSIS... A cold front will sweep across the state this morning, then an anomalous upper level trough will swing over the northeast conus tonight and Friday. The upper trough will lift out and high pressure will build along the east coast this weekend. A developing storm over the Mississippi Valley will track west of Pennsylvania late Sunday, with the trailing cold front coming through the state on Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A potent cold front, located over Lk Erie at 11Z, is poised to sweep east across the region later this morning. Strong forcing and surging pwats ahead of the front should bring a shower or two to most spots later this morning. Upstream satellite imagery is showing a narrow corridor of partial clearing early this morning ahead of the cold front across western Pa. This clearing and subsequent diurnal heating is expected to cause intensification of frontal convection over southeast Pa around midday. Modest capes, combined with strong wind fields, could produce a few strong to severe thunderstorms around noon from Harrisburg south and east. Strong post-frontal winds are expected to drive much colder air into the region this afternoon. Latest bufkit soundings support peak gusts of 45-50kts across the southeast part of the state and closer to 40kts elsewhere. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... An anomalous upper trough over the Grt Lks will pivot southeast across the region tonight and Friday. Deep cyclonic flow and cold air with this feature will produce periods of lake enhanced upslope snow across the Allegheny Plateau and residual flurries/sprinkles to the lee of the Appalachians. A moist sfc-700mb layer, combined with strong orographic lift, will focus most persistent snow across Warren County and the Laurel Highlands, where some 2-3 inch amounts appear likely tonight into early Friday. Elsewhere across the Allegheny Plateau, expect accumulations to be limited to a coating on non-pavement surfaces. Plenty of stratocu and 850 temps well below normal will translate to a very chilly Friday, with highs 15 to 20 degrees below average in most spots. Snow showers over the Alleghenies should taper off Friday PM, as the upper trough begins to lift out. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... The extended period begins cold as Canadian high pressures builds into the region Friday night, maintaining breezy conditions overnight that should prevent widespread frost from forming over the Lower Susq. High pressure crosses the area on Saturday with moderating temperatures (still below avg highs) and dry conditions. Temperatures continue trend warmer on Sunday with increasing clouds as high pressure slides off the East coast. Widespread rainfall expected to begin early next week with anomalous moisture flux spreading into central PA in advance of low pressure tracking northeast from the lower MS Valley. Showers remain possible on Tuesday with secondary cold front crossing the Appalachians, followed by another shot of colder air for midweek. && .AVIATION /11Z THURSDAY THROUGH MONDAY/... For the 12Z TAF package, I did slow down low CIGS some, given that the cold front is still well to the west, and the lower conditions lag the front some. Also not clear cut if lower CIGS can get very far to the east, as the airmass either side of the front not all that moist. Northern edge of the complex that kicked up the wind from the wind from southeast, especially at AOO is pulling east of the area. Some storms trying to form east of this complex, but south of our area. The main thing I did earlier when I came in was to put some snow showers in at BFD and JST after sunset this evening, given how cold the airmass is. .Outlook... Fri...Low cigs/rain/snow showers likely NW 1/2. Gusty winds 25-35kt from 270-300 degrees subsiding Friday night. Sat...Low cigs psbl early then trending VFR. Light rain showers psbl late. Sun...VFR early. Chance rain showers by aftn. Strong/gusty southerly winds psbl Sunday afternoon depending on track/development of sfc low forecast to move east from the Mississippi Valley. Mon...Reduced cigs/vsbys in widespread rain. Strong/gusty southerly winds continue turning westerly late in the period. && .CTP WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 6 PM EDT this evening for PAZ036-056>059- 063>066. && SYNOPSIS...Fitzgerald NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald LONG TERM...Jurewicz/RXR/Colbert AVIATION...Martin
Hazardous Weather Outlook National Weather Service State College PA 448 AM EDT Thu Apr 9 2020 PAZ004>006-010>012-017>019-024>028-033>035-037-041-042-045-046- 049>053-100900- Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield- Northern Centre-Southern Centre-Cambria-Blair-Huntingdon-Mifflin- Juniata-Somerset-Bedford-Fulton-Tioga-Northern Lycoming-Sullivan- Southern Clinton-Southern Lycoming-Union-Snyder-Montour- Northumberland-Columbia- 448 AM EDT Thu Apr 9 2020 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. PAZ036-056>059-063>066-100900- Franklin-Perry-Dauphin-Schuylkill-Lebanon-Cumberland-Adams-York- Lancaster- 448 AM EDT Thu Apr 9 2020 ...WIND ADVISORY IN EFFECT FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING... This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Please listen to NOAA Weather Radio or go to weather.gov/StateCollege on the internet for more information about the following hazards. Wind Advisory. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1112 AM EDT THU APR 09 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1112 AM TSTM WND GST NWS STATE COLLEGE 40.83N 77.85W
04/09/2020 M51 MPH CENTRE PA NWS OFFICE
&&
EVENT NUMBER CTP2000195
RXRPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1117 AM EDT THU APR 09 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1112 AM TSTM WND GST ALTOONA AIRPORT 40.30N 78.32W
04/09/2020 M54 MPH BLAIR PA ASOS
&&
EVENT NUMBER CTP2000196
RXRSpecial Weather Statement
National Weather Service State College PA
1128 AM EDT Thu Apr 9 2020
PAZ036-057>059-063>066-091615-
York PA-Lancaster PA-Adams PA-Franklin PA-Cumberland PA-Lebanon PA-
Dauphin PA-Schuylkill PA-
1128 AM EDT Thu Apr 9 2020
...SPECIAL WEATHER STATEMENT FOR PARTS OF LANCASTER...SCHUYLKILL...
ADAMS...YORK...DAUPHIN...FRANKLIN...CUMBERLAND...AND LEBANON COUNTIES
UNTIL 1215 PM EDT...
At 1127 AM EDT, Doppler radar indicated showers along a line
extending from West Hazleton to near Fort Indiantown Gap to Wayne
Heights. Movement was east at 50 mph.
Wind gusts 40 to 50 mph and pea size hail are possible.
These showers will be near...
Fredericksburg, Lickdale and Pine Grove around 1135 AM EDT.
Myerstown and Richland around 1145 AM EDT.
Lake Heritage and Bonneauville around 1150 AM EDT.
Littlestown around 1155 AM EDT.
Hanover, Pennville and McSherrystown around 1200 PM EDT.
Parkville around 1205 PM EDT.
Other locations impacted by these showers include Arendtsville, York
Haven, Ravine, Mary-D and Gardners.
LAT...LON 4047 7661 4093 7611 4091 7600 4073 7576
4064 7598 4057 7602 4049 7644 4021 7599
3972 7664 3972 7761
TIME...MOT...LOC 1527Z 271DEG 47KT 4097 7601 4047 7656 3972 7756
SteinbuglSpecial Weather Statement
National Weather Service State College PA
1144 AM EDT Thu Apr 9 2020
PAZ019-026>028-035-036-045-046-049>053-056-057-063-064-091630-
Southern Lycoming PA-Union PA-Franklin PA-Juniata PA-Huntingdon PA-
Dauphin PA-Snyder PA-Southern Centre PA-Columbia PA-Perry PA-
Southern Clinton PA-Fulton PA-Northumberland PA-Adams PA-
Cumberland PA-Montour PA-Mifflin PA-
1144 AM EDT Thu Apr 9 2020
...SPECIAL WEATHER STATEMENT FOR PARTS OF NORTHUMBERLAND...
HUNTINGDON...DAUPHIN...FRANKLIN...SNYDER...COLUMBIA...UNION...
PERRY...CUMBERLAND...ADAMS...MIFFLIN...JUNIATA...FULTON...LYCOMING...
AND MONTOUR COUNTIES UNTIL 1230 PM EDT...
At 1143 AM EDT, Doppler radar indicated gusty showers and a few
thunderstorms along a line extending from Williamsport to Alfarata
to near Fort Littleton. Movement was east at 50 mph.
Wind gusts of up to 55 mph and pea size hail are possible.
Locations impacted include...
Harrisburg, Williamsport, Chambersburg, Carlisle, Bloomsburg,
Waynesboro, Sunbury, Mechanicsburg, Camp Hill, Shamokin, Milton,
Enola, Lewisburg, Selinsgrove, Shippensburg, Danville, Montoursville,
Greencastle, Northumberland and Mifflinburg.
LAT...LON 3972 7835 4064 7749 4133 7707 4136 7688
4128 7645 4130 7641 4129 7631 4113 7627
4070 7659 4066 7670 4062 7665 4023 7693
3972 7759
TIME...MOT...LOC 1543Z 276DEG 45KT 4125 7706 4064 7744 4009 7790
RXRPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1148 AM EDT THU APR 09 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1135 AM NON-TSTM WND GST REEDSVILLE 40.66N 77.60W
04/09/2020 M64 MPH MIFFLIN PA AWOS
&&
EVENT NUMBER CTP2000197
RXRSpecial Weather Statement
National Weather Service State College PA
1206 PM EDT Thu Apr 9 2020
PAZ042-091630-
Sullivan PA-
1206 PM EDT Thu Apr 9 2020
...SPECIAL WEATHER STATEMENT FOR PARTS OF SULLIVAN COUNTY UNTIL 1230
PM EDT...
At 1206 PM EDT, Doppler radar indicated gusty showers along a line
extending from near Lovelton to near Lairdsville. Movement was east
at 40 mph.
Wind gusts 40 to 50 mph are likely.
Locations impacted include...
Ricketts Glen State Park, Muncy Valley, Dushore, Laporte and Eagles
Mere.
LAT...LON 4149 7624 4131 7631 4131 7641 4128 7645
4130 7659 4135 7666 4156 7642 4154 7622
TIME...MOT...LOC 1606Z 278DEG 45KT 4155 7628 4128 7663
RXRThe Philadelphia radar (KDIX), 163 km away, was scanning. The volume nearest the first event began at 16:10 UTC.
6 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees in Lititz.
A severe thunderstorm producing winds estimated near 60 mph knocked down a large tree across Route 283 westbound west of Landisville.
A severe thunderstorm produced a 58 mph wind gusts recorded by the ASOS at Lancaster Airport (KLNS).
A severe thunderstorm producing winds estimated near 60 mph knocked down several trees onto Route 30 in Paradise Township.
A severe thunderstorm producing winds estimated near 60 mph knocked down several large tree branches in Leola.
A severe thunderstorm producing winds estimated near 60 mph knocked down several trees near Pleasant Grove.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2020Every state in 2020This day in weather historyWarnings in Pennsylvania, April 2020
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: 884686, 884687, 884691, 884688, 884689, 884692.