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Powerful Pacific Storm to Continue Impacting Northern California; Heavy Snow in the Appalachians and Portions of the Northeast

A strong atmospheric river will continue to impact northern California with heavy rain and life-threatening flooding through Friday. Unsettled weather is expected across much of the Northeast and Great Lakes over the next few days, including the likelihood of heavy snow in the central Appalachians and higher elevations of northeastern Pennsylvania and southern New York. Read More >

WINTER STORM SUMMARY FOR
DECEMBER 14, 2013 TO DECEMBER 15, 2013 EVENT

Synopsis

An area of low pressure developed across the Southeastern United States during December 13th into the 14th, then tracked across portions of the Delmarva region during the night of December 14th. The storm then tracked northeastward and away from our area while strengthening during the morning of December 15th. This storm brought a variety of precipitation types to the region.

Watches/Warnings/Advisories

At 3:33 AM Friday, December 13th a Winter Storm Watch was issued for December 14th for the following counties in New Jersey; Morris, Hunterdon, Somerset, Sussex and Warren. In Pennsylvania; Western Chester, Western Montgomery, Upper Bucks, Carbon, Monroe, Berks, Lehigh and Northampton. At 3:24 PM December 13th, the entire Watch area was upgraded to a Winter Storm Warning. Also at this time, a Winter Weather Advisory was issued for the following counties in Pennsylvania; Delaware, Philadelphia, Eastern Chester, Eastern Montgomery and Lower Bucks. In New Jersey; Middlesex, Mercer, Western Monmouth, Salem, Gloucester, Camden, and Northwestern Burlington; New Castle in Delaware and Cecil in Maryland.

At 3:50 AM December 14th, no changes were made to the counties in the warnings and advisories except the ending time of the advisories were extended some. At 6:40 PM December 14th, the Winter Weather Advisory was extended until 9:00 PM for the following counties in New Jersey; Western Monmouth, Salem, Gloucester, Camden and Northwestern Burlington; Delaware and Philadelphia in Pennsylvania; New Castle in Delaware and Cecil in Maryland. At 8:59 PM, this same Winter Weather Advisory was then extended until Midnight. At 10:01 PM, the Winter Weather Advisory was upgraded to a Winter Storm Warning for the following counties in Pennsylvania; Eastern Chester, Eastern Montgomery and Lower Bucks, and in New Jersey; Middlesex and Mercer. The other warnings and advisories were unchanged.

At 12:06 AM December 15th, the Winter Weather Advisory was cancelled for the following counties in New Jersey; Western Monmouth, Salem, Gloucester, Camden and Northwestern Burlington; New Castle in Delaware and Cecil in Maryland. At this time also, the Winter Weather Advisory was extended until 3:00 AM for Delaware and Philadelphia counties in Pennsylvania. This advisory was then allowed to expire at 3:00 AM and the Winter Storm Warnings remained in effect until 5:00 AM. At 4:54 AM December 15th, the Winter Storm Warnings were allowed to expire at 5:00 AM.

Precipitation/Temperatures/Winds

Snow overspread the area during the day on the 14th. While most areas saw snow for awhile, closer to the coast across southern New Jersey and into central and southern Delaware the frozen or freezing precipitation did not last nearly as long. As the storm continued to organize to our south, snow became heavy at times across portions of eastern Pennsylvania and northern New Jersey. However, warmer air arrived resulting in a change to sleet, freezing rain and rain. The precipitation tapered off during the late evening of the 14th, however some drizzle or freezing drizzle continued into the early morning hours of the 15th.

Snowfall totals were generally 4-12 inches across eastern Pennsylvania and northwestern New Jersey with lesser amounts toward Philadelphia. Freezing rain resulted in ice accumulations ranging from about a tenth of an inch along the Interstate 95 corridor to about 0.20-0.40 inches to the north and west.

There was a tremendous temperature gradient across our area during the height of the storm with mid to upper 50s across southern Delaware, meanwhile at the same time temperatures were only in the low to mid teens in the Poconos. Gradual warming of the surface temperatures occurred all the way to the Poconos early on the 15th, however several areas across northeastern Pennsylvania and northwestern New Jersey did not get above freezing. Northeast to north winds were generally in the 10-20 mph range although there were areas of higher gusts.

Significant Impacts/Aspects

The combination of snow and then ice resulted in hazardous travel across eastern Pennsylvania, mainly northern and western New Jersey, northern Delaware and northeastern Maryland. The more noted impacts were north and west of the Interstate 95 corridor where significant snow accumulations occurred following by a period of icing. This resulted in snow covered and slippery roadways. The conditions improved on the 15th as the storm ended and road crews continued to treat and clear the roadways. The combination of the snow and then ice caused some tree limbs and power lines to fall, resulting in some power outages.

Notes

Information contained in this summary is preliminary. More complete and/or detailed information may be contained in subsequent monthly NOAA storm data publications.