A complex area of low pressure over the Middle Atlantic, which involved several individual centers, slowly consolidated off the Virginia Capes Tuesday Morning, March 20th into Wednesday March 20st along a frontal boundary. This primary low, the fourth nor'easter of the month, gradually moved northeast Wednesday Night, to a position southeast of the 40 North/70 West ���Benchmark��� coordinates on Thursday Morning.
As precipitation moved northward into a colder air mass across the area on on Tuesday, March 20th, snow and sleet developed in Southeast Pennsylvania during the afternoon hours.
During Tuesday evening, a mixed bag of precipitation developed, with freezing rain, sleet, and snow, except rain closer to the coast.
Freezing rain lead to ice accretion up to 0.20��� across portions of far Southeastern Pennsylvania, causing downed trees and limbs, which impacted power lines, and lead to power outages.
After midnight, during the overnight hours of Tuesday into Wednesday, a changeover to snow occurred across the Lehigh Valley, while the higher elevations of Eastern Pennsylvania remained dry. A gradual change over to snow occurred across the remainder of Eastern Pennsylvania through the mid-morning hours of Wednesday, March 21st. Meanwhile, snow began in the higher elevations of Eastern Pennsylvania during the mid to late morning hours of Wednesday.
Moderate to heavy snowfall developed, and gradually overspread Eastern Pennsylvania from Wednesday Morning into the evening. Snowfall rates, particularly outside of the higher elevations of Northeast Pennsylvania were around one inch per hour at times. While the snow ended Wednesday Evening in the higher elevations of Eastern Pennsylvania, it gradually ended from west to east across the remainder of the region around midnight.
Snowfall amounts ranged from less than 6 inches in the Southern Poconos of Eastern Pennsylvania to around 15 inches in the Lehigh Valley, then tapering down to 6 to 8 inches in far Southeast Pennsylvania.
The weight of the heavy, wet snow brought down trees, limbs, and power lines across portions of far Southeast Pennsylvania, which lead to power outages.

Winter Storm in WESTERN MONTGOMERY, PENNSYLVANIA
From 21-MAR-18 03:00:00 to 22-MAR-18 00:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Precipitation began as a rain-snow-sleet-freezing rain mixture during the late afternoon hours on March 20th, adversely affecting the evening commute. After a lull during the overnight hours, a drier snow began falling by late morning on the 21st, becoming heavy at times during the afternoon and evening hours. Snowfall amounts generally ranged from 12 to 15 inches.

Winter Storm in UPPER BUCKS, PENNSYLVANIA
From 21-MAR-18 04:00:00 to 22-MAR-18 00:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  Banding provided the mechanism for snowfall totals exceeding one foot in many locations.  Some reported snowfall amounts include: 14.0 inches in West Rockhill Township, 14.0 inches in Perkasie, 13.2 inches in Springtown, 13.0 inches in Bedminster, 12.0 inches in Sellersville, and 9.5 inches in Spinnerstown.

Winter Storm in WESTERN CHESTER, PENNSYLVANIA
From 21-MAR-18 07:00:00 to 21-MAR-18 23:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  The highest snowfall totals from the event occurred along and north of I-276.  Some reported snowfall amounts include: 10.3 inches in Uwchlan Township, 10.0 inches in Elverson, and 8.6 inches in Glenmoore.

Winter Storm in EASTERN CHESTER, PENNSYLVANIA
From 21-MAR-18 07:00:00 to 21-MAR-18 23:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  The highest snowfall totals from the event occurred along and north of I-276.  Some reported snowfall amounts include: 11.2 inches in Berwyn, 9.5 inches in Valley Forge, 6.5 inches in West Chester, and 5.0 inches in Chadds Ford.

Winter Storm in EASTERN MONTGOMERY, PENNSYLVANIA
From 21-MAR-18 08:00:00 to 22-MAR-18 00:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a rain-snow-sleet-freezing rain mixture during the late afternoon hours on March 20th, adversely affecting the evening commute. After a lull during the overnight hours, a drier snow began falling by late morning on the 21st, becoming heavy at times during the afternoon and evening hours. The highest snowfall totals from the event occurred along and north of I-276.  Some reported snowfall amounts include: 16.5 inches in Lansdale, 13.1 inches in Montgomeryville, 12.5 inches in Hatfield, 10.4 inches in King of Prussia, 10.2 inches in North Wales, 9.5 inches in Horsham, 6.8 inches in Chestnut Hill, and 6.0 inches in Wyncote.

Winter Storm in LEHIGH, PENNSYLVANIA
From 21-MAR-18 03:00:00 to 22-MAR-18 00:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  Some reported snowfall amounts include: 16.2 inches in Zionsville, 16.0 inches in Macungie, 15.0 inches in Emmaues, 14.5 inches in Alburtis, 14.5 inches in Coopersburg, 13.8 inches in Center Valley, 13.2 inches at Lehigh Valley International Airport, 12.5 inches in Allentown, 10.5 inches in Orefield, and 9.9 inches in Neffs.

Winter Storm in BERKS, PENNSYLVANIA
From 21-MAR-18 03:00:00 to 22-MAR-18 01:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  The heaviest snow from this event fell in the eastern one-third of the county, generally south of I-78. Some reported snowfall amounts include: 15.5 inches in Huffs Church, 14.0 inches in Boyertown, 13.0 inches in Kutztown, 12.5 inches in Reading, 12.0 inches in West Wyomissing, 11.7 inches in West Lawn, 11.0 inches near Alburtis, 9.0 inches in Hamburg, and 8.5 inches in Jefferson Township.

Winter Storm in CARBON, PENNSYLVANIA
From 21-MAR-18 04:00:00 to 22-MAR-18 21:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  The heaviest snow from this event fell in the southern half of the county.  Some snowfall reports include:  9.8 inches 3 miles west-southwest of Lehighton, 8.8 inches in Lehighton, 8.5 inches near Danielsville, 7.0 inches in Lower Towamensing Township, and 4.0 inches in Albrightsville.

Winter Storm in MONROE, PENNSYLVANIA
From 21-MAR-18 05:00:00 to 22-MAR-18 21:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  The heaviest snow from this event fell in the southern one-third of the county, generally south of I-80, with a sharp drop off in the far north. Some snowfall reports include:  9.8 inches near Bossardsville, 7.8 inches in Rossland, 7.0 inches in Stroudsburg, 5.0 inches in Mount Pocono, 4.2 inches in Mount Pocono, 3.5 inches in Pocono Summit, 3.0 inches in Tobyhanna, and 1.0 inches in Gilbert.

Winter Storm in LOWER BUCKS, PENNSYLVANIA
From 21-MAR-18 08:00:00 to 22-MAR-18 01:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a rain-snow-sleet-freezing rain mixture during the late afternoon hours on March 20th, adversely affecting the evening commute. After a lull during the overnight hours, a drier snow began falling by late morning on the 21st, becoming heavy at times during the afternoon and evening hours.  Some reported snowfall amounts include: 10.8 inches in Langhorne, 10.5 inches in Southampton, 10.0 inches in Chalfont, 9.5 inches in Washingtons Crossing, 9.5 inches in Levittown, 8.5 inches in Morrisville, 8.1 inches in Penndel, 8.0 inches in Oakford, and 7.2 inches in Newtown.

Winter Storm in DELAWARE, PENNSYLVANIA
From 21-MAR-18 09:00:00 to 21-MAR-18 23:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a rain-snow-sleet-freezing rain mixture during the late afternoon hours on March 20th, adversely affecting the evening commute. After a lull during the overnight hours, a drier snow began falling by late morning on the 21st, becoming heavy at times during the afternoon and evening hours.  Some reported snowfall amounts include: 10.0 inches in Wayne, 9.6 inches in Chadds Ford, 9.0 inches in Garnet Valley, 8.7 inches in Ridley Park, 8.2 inches in Thornton, 8.0 inches in Upper Darby Township, 8.0 inches in Broomall, 7.6 inches at Philadelphia International Airport,  and 6.9 inches in Media.

Winter Storm in PHILADELPHIA, PENNSYLVANIA
From 21-MAR-18 09:00:00 to 21-MAR-18 23:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a rain-snow-sleet-freezing rain mixture during the late afternoon hours on March 20th, adversely affecting the evening commute. After a lull during the overnight hours, a drier snow began falling by late morning on the 21st, becoming heavy at times during the afternoon and evening hours.  Some reported snowfall amounts include: 9.3 inches in Roxborough, 8.4 inches in Fox Chase, 8.0 inches in Northeast Philadelphia, 7.8 inches in Mayfair, 7.6 inches at Philadelphia International Airport, 7.4 inches in Somerton, 7.0 inches in Center City, 6.6 inches at the Franklin Institute, and 5.0 inches in South Philadelphia.

Winter Storm in NORTHAMPTON, PENNSYLVANIA
From 21-MAR-18 03:00:00 to 22-MAR-18 00:00:00 (EST-5)
Reported by: Trained Spotter

Precipitation began as a wet, heavy snow during the evening hours on March 20th. After a lull during the overnight hours, a drier snow began falling, heavy at times, during the afternoon and evening hours on March 21st.  The highest snowfall totals from the event occurred along and south of I-78. Some reported snowfall amounts include: 14.5 inches in Williams Township, 13.9 inches in Hellertown, 12.1 inches in Easton, 11.0 inches in Delp, 10.0 inches in Cherry Hill, 8.5 inches in Portland, 8.0 inches in Tatamy, and 5.6 inches in Nazareth.