An arctic front swept through the region during the midday hours of January 25, 2007. Ahead of this front,
the air temperatures were generally in the 30s and scattered snow showers developed during the morning hours. However, a line
of snow squalls became organized across the Lehigh Valley during the late morning hours and quickly moved to the east-southeast
through the early to mid afternoon. These snow squalls were accompanied by rapidly lowering visibilities down to about a quarter
of a mile in the most intense snow for a short period of time. Gusty winds also accompanied parts of the snow squall along
with temperatures dropping below freezing. This produced a good coating or so in several locations from eastern Pennsylvania
and central and southern New Jersey. The show was not over though. As the arctic front settled across Delaware, an strong
upper-level disturbance tracked from northwestern Pennylvania during the afternoon to Delaware during the evening hours. This
produced numerous snow showers and squalls across Maryland's Eastern Shore, Delaware and clipping far southern New Jersey.
As the upper-level disturbance moved overhead, an area of intense snow squalls tracked from Berks and Chester Counties, southeastward
across southern New Jersey. All the activity gradually moved off the southeastern New Jersey coast toward the midnight hour.
An arctic airmass continued to encompass the entire region. A fast moving low pressure system, commonly referred
to as a clipper, moved from western Canada to the central Plains and Ohio Valley on February 6th. This system then quickly
crossed the Mid Atlantic region during the early morning hours of February 7th. As the system approached our region, an area
of snow was produced ahead of this clipper. Snow overspread Maryland's Eastern Shore, Delaware, southeastern Pennsylvania
and southern New Jersey during the early morning hours of the 7th. While the snowfall was not heavy regarding intensity, a
couple of inches of fluffy snow occurred around parts of the region. The clipper quickly moved out to sea during the morning
and allowed a clearing sky to build across the area.
An area of low pressure tracked across southeastern Canada during the 12th, which brought an arctic front
across our region late on the 12th. As this occurred, a strong area of high pressure located across central Canada built down
into the Northeast, allowing very cold air to spill southward ultimately leading to what is known as cold air damming. This
occurs east of the mountains down through the Mid Atlantic states. Meanwhile a Pacific storm slammed onto the California coast
during the 11th and as it moved eastward, a new area of low pressure developed across southeastern Colorado and the Texas
Panhandle. This storm became impressive as it moved into the Ohio Valley during the 13th. However as additional energy moved
into the eastern part of the country, a new area of low pressure developed near the North Carolina coast late on the 13th.
Moisture associated with the first storm streamed eastward during the 13th. This allowed mainly light snow to slowly overspread
the region from southwest to northeast. As the secondary area of low pressure became more organized to our south, moisture
began to fill in across North Carolina and Virginia and this moved northward. The arctic front that slipped through our area
on the 12th was positioned across the southern Delmarva and this began a northward jog during the night of the 13th and morning
of the 14th.
The intensifying area of low pressure tracked very near southern Delaware and then slid very close to the
New Jersey Shore during the morning of the 14th. This system continued to intensify as it moved into New England during the
afternoon and evening of the 14th. The upper-level system then passed overhead during the evening of the 14th, with the entire
system pretty much a memory by late that evening.
A winter storm affected the region on February 25 and 26, 2007. A low pressure system began to intensify in
the Great Plains region the night of Friday the 23rd. The storm continued to intensify during the day on Saturday the 24th,
which helped to pull a substantial amount of moisture from the Gulf of Mexico with it across much of the central part of the
country. Meanwhile, a cold high pressure system was located in eastern Canada, which kept the Mid-Atlantic region cold near
the surface. By Sunday the 25th, the low pressure system had moved near the Upper Mississippi River Valley, with an occluded
front extending just south of the Great Lakes, through the Ohio River Valley, and down the Appalachian Mountain chain. The
occluded front ended near Northeast Georgia, where it intersected a cold front that extended south into the Gulf of Mexico,
and a warm front that extended northeastward through the Carolinas and into the Atlantic Ocean. As these frontal boundaries
began to slowly move toward the region, moisture began to "override" the fronts, and because the air was cold enough through
the entire atmosphere, the precipitation fell as snow, and rather heavy at times at the onset.
As warm air began to move into the region later in the afternoon and evening, both at the surface and aloft,
this began to change the precipitation to a rain/freezing rain/sleet/snow mixture. While not everywhere saw each of these
precipitation types, most areas did experience at least two. By Sunday evening, a second area of low pressure had begun to
develop and intensify near the Delmarva coast. This helped to intensify some precipitation, especially along the coast of
New Jersey where it was mostly rain by this time.
This storm was rather interesting as just two days prior most of the region had temperatures well into the
70s. However, winter made a huge return as a cold front gradually settled southeastward across the region during the 15th.
As a result of the passage of this cold front, colder air began to seep southward as a large high pressure system became anchored
across southeastern Canada. Meanwhile, an area of low pressure developed along the front across the Deep South and this allowed
an abundance of moisture to move northward later on the 15th. As the main area of low pressure continued to organize across
eastern North Carolina, much colder air settled southward into a good part of our area. As the moisture continued to move
through, the precipitation transitioned over to sleet, freezing rain and snow; however, milder air from the ocean influence
kept coastal areas mostly rain. As the storm moved up the coast on the 16th, moderate to heavy precipitation varying between
snow, sleet and rain continued to hammer the area. Gradually as the storm was due east of New Jersey during the evening of
the 16th, the precipitation began to taper off from southwest to northeast, however the damage was certainly done across a
good chunk of our region.