WINTER STORM SUMMARY FOR
MARCH 01, 2009 TO MARCH 2, 2009 EVENT

Synopsis

A cold front pushed through the Mid Atlantic Friday night, February 27th, into Saturday, the 28th, before stalling to the south and east of the region. A coastal low developed along this stalled boundary near the Carolinas and began to propagate northeastward on Sunday, March 1st. As the coastal low moved offshore and northeastward on the 1st and 2nd, winds turned to the northeast and ushered in plenty of moisture across the region. The precipitation ended when the surface and an associated upper level low both moved far enough to the northeast on Monday evening.

Watches/Warnings/Advisories

A Winter Storm Watch was issued at 4:10 AM EST on Saturday February 28th and was in effect from Sunday March 1st at 6:00 PM EST until Monday March 2nd at 12:00 PM EST. The watch area included Chester, Montgomery, Bucks, Delaware, and Philadelphia counties in Pennsylvania; New Castle, Kent, and Sussex counties in Delaware; Cecil, Kent, Talbot, Queen Annes, and Caroline counties in Maryland; Sussex, Warren, Morris, Hunterdon, Somerset, Middlesex, Monmouth, Mercer, Salem, Gloucester, Camden, Burlington, Ocean, Cumberland, Atlantic, and Cape May counties in New Jersey. 

The Winter Storm Watch was upgraded to a Winter Storm Warning at 3:30 AM EST on Sunday March 1st for Sussex, Warren, Morris, Hunterdon, Somerset, Middlesex, Monmouth, Mercer, Gloucester, Camden, Burlington, and Ocean counties in New Jersey; Chester, Montgomery, Bucks, Delaware, Carbon and Philadelphia counties in Pennsylvania; the counties of , Monroe, Berks, Lehigh, Northampton in Pennsylvania were added to the warning at this time; the Warning was in effect from 6:00 PM EST on Sunday March 1st until 4:00 PM EST on Monday March 2nd. The Winter Storm Warning was issued at 3:30 AM EST, in effect for all of Delware, Cecil, Kent, Talbot, Caroline, and Queen Annes counties in Maryland; Salem, Cumberland, Atlantic, Ocean, and Cape May counties in New Jersey from 6:00 PM EST on Sunday March 1st until 2:00 PM EST on Monday March 2nd.

At 4:35 AM EST a Special Weather Statement was issued for the entire region noting light snow would start to fall early in the morning and possibly mixing with sleet in the southern areas. At 5:30 AM EST an update to the Winter Storm Warning was issued with no headline changes, followed by a Special Weather Statement at 7:54 AM EST which included the possibility of freezing rain mixing with the sleet and snow across the southern zones. 

By mid-afternoon the storm was steadily approaching from the south and an update to the warning was issued. The 2:45 PM EST update included no headline changes but did make mention of reduced visibilities due to heavy snow fall and strong, gusty winds. At 4:20 PM EST it was decided that a Coastal Flood Advisory would be issued for Kent, and Sussex counties in Delaware; Middlesex, Monmouth, Ocean, Atlantic, Cape May, and the southeastern part of Burlington counties in New Jersey from 9:00 PM EST on Sunday March 1st until 5:00 AM EST Monday March 2nd. The advisory was issued due to the concerns of a storm surge that may result from the advancing coastal low pressure system and also due to high tides running two feet above normal. 

At 11:16 PM EST an update to the Winter Storm Warning was issued with no headline changes. As the coastal storm became closer and the pressure gradient tightened the winds started to pick up dramatically. At 12:49 AM EST on Monday March 2nd, a Special Weather Statement was issued to account for public reports and radar indicated winds in excess of fifty miles per hour; the strong winds were accounted for by the passage of a strong gravity wave. At 1:32 AM EST a statement was issued to account for strong wind gusts in excess of fifty miles per hour entering into the southern tier of New Jersey. At 2:08 AM EST another statement was issued for areas futher east of the prior impact area and finally at 2:35 AM EST the last statement for wind related weather was issued for central New Jersey. 

Another update to the WSW was issued at 3:45 AM EST with no headline changes except for Berks, Carbon, Monroe, Lehigh, and Northampton counties in Pennsylvania where the warning canceled and replaced with a Winter Weather Advisory. with the same ending time of 4:00 PM EST on Monday March 2nd. The Storm Prediction Center in Norman Oklahoma issued a Mesoscale Discussion including a majority of the area for heavy snowfall at 4:38 AM CST. The Storm Prediction Center declared that snowfall rates could be as high as one inch per hour across the region but diminish as the morning progressed. At 5:40 AM EST an updated version of the winter weather message was issued with no headline changes but rather changes to the accumulation totals across the region were dropped a bit. 

One major update to the winter weather message came at 11:55 AM EST with the cancellation of the warning for all of Delaware, Cecil, Kent, Talbot, Queen Annes and Caroline counties in Maryland, and Salem, Cumberland, Atlantic, and Cape May counties in New Jersey; the remianing warnings continued until expiration at 4:00 PM EST as did the Winter Weather Advisory.

Precipitation/Temperatures/Winds

The outer precipitation bands of the approaching coastal low entered into the region from the south affecting parts of southern Maryland and Delaware. A gradual changeover from rain to snow occurred around 7:00 PM EST on Sunday, March 1st. Winds continued to howl out of the northeast and intensified as the low became closer. A gravity wave moved through the region shortly after midnight on the 2nd causing numerous tree limbs and power lines to fall. With temperatures well below freezing and gusty winds, wind chills were reported in the single digits. Snow measurements from the public were plentiful, however, since the snow was very fine and powdery, snow drifting became a factor in trying to get an exact snowfall reading. 

Storm total snowfall maximums (over a foot of snow) were found along the coastal areas in New Jersey and also in the interior areas of Cumberland County in New Jersey. A lesser, but equally impressive (10 to 12 inches), snowfall band existed on a southwest to northeast axis through Talbot County in Maryland to the Delaware state line. Further north, a narrow 8 to 10 inch band set up over northern Chester County, with the axis passing just north of Philadelphia County up through Montgomery and Bucks counties in Pennsylvania and crossing into Hunterdon, Morris, and Sussex counties in New Jersey. All other locales saw at least 3 to 6 inches of snow throughout the event.

Significant Impacts/Aspects

The snow started to fall during the evening hours of Sunday, March 1st with very little impact. As daybreak approached on Monday the 2nd and snowfall rates intensified, the Monday morning commute was significantly impacted. Numerous vehicle accidents were reported all across the region. One accident shut down eight miles of the east-bound Pennsylvania Turnpike north of Philadelphia for several hours. Two seperate accidents on I-78 in northern Berks County closed the eastbound lanes from 9:00AM EST until 4:30 PM EST on Monday, and the westbound lanes from noon until 8:45 PM EST. 

There was about a two hour lull in snowfall mid morning on the 2nd which allowed motorists to travel, excersizing extreme caution, to work as visibilities increased. Snow covered trees and power lines were swung about as strong, gusty winds entered the region during the morning hours. Numerous power outages were reported as an exact outcome of the gusty winds. Schools were closed throughout the region on Monday, March 2nd. 

Two distinct periods of snow were associated with this event. The first period, associated with the surface low, began falling Sunday evening through the overnight hours. The second period of snow, associated with the upper low, began falling around daybreak and continued until about midday. With temperatures in the 20s and dewpoint temperatures in the teens, snow from this event was fine and powdery; strong winds caused drifting and blowing snow. 

The prolonged onshore flow produced tidal anomalies of 1.5 to 2.0 feet Sunday into Monday. Gage data indicated near minor tidal flooding along both the Delmarva and New Jersey coast, and in the Delaware Bay, during the high tide Sunday night into Monday morning. 

Early Monday morning, doppler radar indicated strong outbound winds approaching the region. These winds were in excess of fifty miles per hour at a height of a few hundred feet. With the odd propagation of the wind field, the meteorological reasoning for the cause was that a strong gravity wave moved through the region and produced wind damage swaths in the areas it traversed. 

With temperatures below the freezing mark and dewpoints in the teens, a fine and powdery snow began falling on Sunday evening. The snowfall continued through the early afternoon hours on Monday March 2nd.

Notes

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