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It is very rare for an ice storm warning to be issued for New Jersey. I can count the times any part of New Jersey was under an ice storm warning within the past decade with my two hands. This should highlight the serious nature of this winter storm. Severe icing is expected in the ice storm warning areas which could down trees and power lines. Travel will become impossible and extremely dangerous in the ice storm warning area. The counties under an ice storm warning are Sussex, Warren, Morris, Hunterdon, Somerset, Union, Passaic, Essex, Bergen, Mercer, and Middlesex. Icing reaching warning criteria is 0.25” or greater.
Atlantic, Burlington, Camden, Gloucester, Salem, Ocean, Monmouth, and Cumberland Counties are under a freezing rain advisory. This is another product that is not issued too often. This means some icing is likely, which will cause treacherous driving conditions, but the icing it will not be severe enough to down multiple trees and power lines. Isolated power outages are possible in this area, perhaps more so attributed to people having accidents with electrical poles or trees. The criterion for an advisory for ice is a trace to 0.24”. However, during this particular storm, there is still some uncertainty in this region about how cold the temperatures are during the heavier rain at the surface. Should the temperatures at the surface respond slower to warmer air or should the precipitation be heavier while temperatures are around or below freezing, warning criteria ice could occur here requiring a warning upgrade. This is most likely for Western Monmouth County and the parts of the counties along the Delaware River.
Across the ice storm warning area, some sleet could mix in at times. However, at this present time, it appears icing of over one-half inch can be expected. Some of the guidance indicates record extremes of over one-inch of ice accrual over a portion of the current ice storm warning area. Should these values be realized, this is extremely destructive and serious damage to vegetation and electrical grids would occur. This is most likely in Northwestern New Jersey down through northwestern portions of Central New Jersey. Elsewhere, one-quarter to one-half inch or more of ice may occur. This amount of ice can certainly cause widespread power outages and break branches on trees. It is in this area where temperatures were below freezing much of the day so there is already a glaze maintained from round one and we will be adding to this.
It goes without saying that long-term power outages are possible. I would make sure you have a working generator, non-perishable foods, water, medicine, and very warm clothing in place should you lose electricity.
I am expecting freezing drizzle and light freezing rain across New Jersey this evening. Temperatures in South Jersey, with the exception of Southeastern New Jersey, will drop to around or below freezing as the daylight begins to end. Elsewhere, temperatures are now at or below freezing and they will fall or hold steady. A north or northeast wind will make it very hard for below freezing temperatures to be scoured out at the surface. In addition, the lack of daylight and the snowpack will aid to keeping the colder air locked at the surface. This is called cold-air damming. Elevation and distance are significant factors involved in this process and obviously these factors favor the interior north. Still, icing will begin in most areas tonight and the threat will end in southeastern portions of South Jersey around or after the morning commute. The icing will persist through the morning commute in northwestern portions of Southern New Jersey and Central New Jersey and points north. Then the icing area will shrink to the northern and northwestern areas of New Jersey.
Flooding of streets is likely in areas that see heavy liquid rain. The snow is blocking storm drains and the frozen ground will not handle heavy rain. The rains will runoff allowing for this street flooding. Some creeks and streams may also flood. I should also note that some minor coastal flooding issues could add to the poor drainage flooding. The heaviest liquid rain will be over the shore points that have the least snow cover and also the sandy soils.
Windy conditions could exist for a window of time, especially along the coastline. Gusts could approach 40 MPH. Some thunderstorms are also possible around the warmer portion of this storm. Atlantic City could be around 50 degrees while the interior is much colder.
On Wednesday Night, temperatures will begin to drop rapidly as the system pulls away. This will cause a rapid freeze of any liquid. There could also be some snow showers as this storm begins to move out of our region. Thursday Morning could be a mess as a result of the refreezing of slush and water. Icing areas that never see 32 degree or above air temperatures will have to wait until Friday for the ice to melt if surfaces are not treated well.
Another winter storm is likely on Saturday. The latest computer model guidance suggests a wintry mix will be likely as the “540 Line” moves into the interior. However, we are on the colder side of this coastal storm, so warmer air coming into the region will be limited. Colder air will move in during the storm and the precipitation may end as snow. Anyhow, some sleet and freezing rain cannot be ruled out with even some liquid rain in South Jersey.
Another winter storm is likely Monday into Tuesday. This could be another overrunning event which is followed up by a storm cutting to our west, introducing warmer air, which may include rain or a wintry mix.
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