Intensifying low pressure in the Gulf of Maine dragged a strong cold front across central Pennsylvania during the early morning hours of April 30, 2021. A secondary cold front crossed the area during the day on April 30.
Every event with a place to put it; 10 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
Intensifying low pressure in the Gulf of Maine dragged a strong cold front across central Pennsylvania during the early morning hours of April 30, 2021. A secondary cold front crossed the area during the day on April 30. These systems produced strong winds across the area, particularly across southeastern Pennsylvania.
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, 12:43 PM EST, 17 minutes earlier.
Area Forecast Discussion National Weather Service State College PA 143 PM EDT Fri Apr 30 2021 .SYNOPSIS... April is going out like a lion. It will be very windy today as a storm deepens over New England and pulls unseasonably cold air into the state. Temperatures will be cold today, as well. Conditions will improve on Saturday with high pressure over the southeastern states drawing warm air back into our area. The pattern will remain unsettled with many chances for rain next week. && .NEAR TERM /THROUGH TONIGHT/... 10 am update... The current forecast is in fairly good shape, so just made some cosmetic tweaks through the afternoon. As of late morning, scattered showers were across mainly areas north of I-80, tied to a short wave crossing NY State and northern PA. As this wave moves away to the northeast this afternoon, it will be followed on its heels by another vigorous short wave coming in from lower MI/southern Ontario. Thus, at least a popcorn coverage of showers (perhaps a bit more numerous along portions of the Allegheny Front and across the northern tier) should persist. Once we get into the mid to late afternoon hours, more dominant downward motion should begin to take over, which, enhanced by downslope northwesterly flow into the Susquehanna Valley, is expected to enhance wind gust potential. We're still anticipating 50-60 mph gusts in the Lower Susquehanna Valley, with the prime time for gusts between about 3 and 8 pm. Wind gusts of 35-45 mph should be more common across the rest of central PA, with our present configuration of wind hazards remaining in tact. Still anticipating a chilly night, with generally clearing skies over time. We'll assess the freeze potential more closely for Warren county and the Laurel Highlands in a later update. Previous discussion... Showers getting a little farther s/e than earlier expectations. Will tweak the PoPs for the next 3-4 hrs, and try to dodge the drops on the way home. All else is well. Earlier discussion... Tightening gradient is keeping the wind going, and it will only get stronger through the day. Almost all the area will have gusts into the 40s and the SE will have the strongest gusts, mainly late this afternoon and early this evening. The gustiness will be peaking around or just before sunset. BUFKIT profiles and mixing (with help from downslope) still yields a 50KT+ gust or two in the SE, and the warning is well-placed. Temperatures will go up only a deg or two in the NW today, and less than 10F everywhere. The pocket of coldest air rolls over the NE counties. The leading edge of that good shot of CAA will likely hold some SHRA for the Laurels this aftn. The instability under the deepest part of the trough will cause sct SHRA in the nrn tier/NE mtns right when it will be most gusty. The wind dies down to a mild roar fairly quickly after the peak around sunset, but will still be gusting into the 20s in the morning in the east. The temperatures tonight should fall well with the cold pocket overhead early tonight, skies clearing out, and the some decrease in wind - mainly in the west. The MOS guidance has come in much colder than previous blend of models output. Thus, we have increased confidence in temps going down to or below freezing over much of the western and northern mountains. The wind could hold things up, so it's not yet a slam-dunk. Will expand the Freeze Watch to include the Laurels. While the temps get down to the m30s over much of the area, the wind should keep us from having to deal with frost (where it does not straight-up freeze). note: We've made a (one-time) modification to the start of the frost/freeze program for this Spring for the Laurels and the northern Alleghenies - bumping up the start date of the program by 10 days on the whole. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... 8H advection sign turns around before sunrise, and the temps should pop up quickly as the May sun works it's wonders. Not every day do we have warm advection on a NW wind, as it should be Sat morning. The anticyclone will settle over the Deep South and a good warm up is in store with sfc wind backing to the SW by late aftn. Maxes will be back closer to normals, which are in the 60s. There is just a slight chc of a SHRA Sat aftn in the far nrn counties as a short wave drops down from the Upper Great Lakes. RH will drop to the 20s for much of the area, but winds and likely fuels should not meet Red Flag criteria. The green up will continue nicely with the 1-2" rainfall over the nrn tier these past 48 hrs. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Q-stationary frontal zone near PA/NY border keeps low POPs in the northern tier on Sunday. The big story by the end of the weekend will be much warmer temperatures returning to CPA with highs +15F warmer than Saturday in the 70-80F range. The early to mid week period looks rather unsettled with a pair of southern stream shortwaves likely bringing rounds of showers and t-storms Monday through Wednesday. Model and ensemble data favor a deepening trough over the Eastern U.S. from late week into next weekend with potential for a coastal low near the Mid-Atlantic region. Despite a modest cool down Sunday into Monday, temperatures should remain above average early next week. NBM trended warmer and wetter during this period. Expect a seasonably cooler trend during the mid to late week period with below average daytime temps to close out the week. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... An area of -RA sweeping through the region on the heels of gusty northwest winds. Only a localized area of reduced celings and visibilites with the next area of showers. Expect mainly VFR to continue as they pass from west to east. However, in the most isolated heavy shower, some graupel is likely. Winds will remain gusty with some up to 45KTS over highher elevations. As any surface winds decrease slightly overnight, WS020 will continue with winds above the surface remaining strong through sunrise. Expect winds to diminish somewhat Saturday. Outlook... Sun...MVFR in showers across the norther tier. Mon...Mainly VFR conditions, but a chance of showers late NW. Tue...Mainly VFR conditions, but a chance of showers. && .CTP WATCHES/WARNINGS/ADVISORIES... Freeze Watch from midnight EDT tonight through Saturday morning for PAZ004-017-018-024-033. Wind Advisory until midnight EDT tonight for PAZ006-011-012- 017>019-024>028-033-034-037-041-042-045-046-049>053. High Wind Warning until 2 AM EDT Saturday for PAZ035-036- 056>059-063>066. && SYNOPSIS...Dangelo NEAR TERM...Jurewicz/Dangelo SHORT TERM...Dangelo LONG TERM...Steinbugl AVIATION...Banghoff/Tyburski
Hazardous Weather Outlook National Weather Service State College PA 345 AM EDT Fri Apr 30 2021 PAZ035-036-056>059-063>066-010745- Fulton-Franklin-Perry-Dauphin-Schuylkill-Lebanon-Cumberland-Adams- York-Lancaster- 345 AM EDT Fri Apr 30 2021 ...HIGH WIND WARNING IN EFFECT FROM 2 PM THIS AFTERNOON TO 2 AM EDT SATURDAY... 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. High Wind Warning. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ006-011-012-019-025>028-034-037-041-042-045-046-049>053-010745- Potter-Cameron-Northern Clinton-Southern Centre-Blair-Huntingdon- Mifflin-Juniata-Bedford-Tioga-Northern Lycoming-Sullivan- Southern Clinton-Southern Lycoming-Union-Snyder-Montour- Northumberland-Columbia- 345 AM EDT Fri Apr 30 2021 ...WIND ADVISORY IN EFFECT FROM NOON TODAY TO MIDNIGHT EDT TONIGHT... 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...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ017-018-024-033-010745- Clearfield-Northern Centre-Cambria-Somerset- 345 AM EDT Fri Apr 30 2021 ...WIND ADVISORY IN EFFECT FROM NOON TODAY TO MIDNIGHT EDT TONIGHT... ...FREEZE WATCH IN EFFECT FROM LATE TONIGHT THROUGH SATURDAY MORNING... 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. Freeze Watch. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. Please listen to NOAA Weather Radio or go to weather.gov/StateCollege on the internet for more information about the following hazards. Freeze Watch. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ004-010745- Warren- 345 AM EDT Fri Apr 30 2021 ...FREEZE WATCH IN EFFECT FROM LATE TONIGHT THROUGH SATURDAY MORNING... 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. Freeze Watch. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. Please listen to NOAA Weather Radio or go to weather.gov/StateCollege on the internet for more information about the following hazards. Freeze Watch. .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report significant hazardous weather. PAZ005-010-010745- McKean-Elk- 345 AM EDT Fri Apr 30 2021 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...Saturday through Thursday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The national radar mosaic for the moment the first event began.
10 high wind. Local standard time, as filed.
High winds were estimated to have gusted to near 60 mph in Adams County on April 30, 2021. These winds knocked down a tree onto an occupied porta-potty at Gettysburg National Battlefield, entrapping and causing minor injuries to the occupant.
High winds were estimated to have gusted to near 60 mph in Cumberland County on April 30, 2021.
High winds were estimated to have gusted to near 60 mph in Dauphin County on April 30, 2021. This wind event produced numerous downed trees and power lines in Dauphin County, particularly in the central and southern parts of the county. A 62 mph gust was measured by the ASOS at Harrisburg International Airport.
High winds were estimated to have gusted to near 60 mph in Lancaster County on April 30, 2021. These winds knocked down a large tree branch onto a home approximately one mile north of Columbia, destroying the roof of the home. A 64 mph gust was measured by a CWOP site in Manheim.
High winds were estimated to have gusted to near 60 mph in Franklin County on April 30, 2021.
High winds were estimated to have gusted to near 60 mph in Fulton County on April 30, 2021.
High winds were estimated to have gusted to near 60 mph in Lebanon County on April 30, 2021.
High winds were estimated to have gusted to near 60 mph in York County on April 30, 2021.
High winds were estimated to have gusted to near 60 mph in Perry County on April 30, 2021.
High winds were estimated to have gusted to near 60 mph in Schuylkill County on April 30, 2021.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2021Every state in 2021This day in weather historyWarnings in Pennsylvania, April 2021
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: 948538, 948539, 948540, 948541, 948542, 948543, 948544, 948545, 948546, 948547.