Flooding Across New Jersey

As expected, Northern New Jersey’s Passaic River basin is experiencing major flooding. Some areas will approach historic flood stages which will result in widespread devastation. The worst will be near Pompton Plains, Lodi, and Pompton Lakes.

Elsewhere, many waterways are nearing flood stage. This map is somewhat misleading to those unfamiliar with how flooding works. Many gages are “near flood stage”, but many will see the waters go above flood stage as the runoff continues to head towards the waterways. Even some waterways not near flood stage right now will see rises throughout the day.

Excessive Rains Over New Jersey, Flooding Very Likely

The excessive rains have arrived in our region, as expected during this time frame. Rainfall rates of more than one-half inch per hour are easily occurring with this band that is forming right along a zone of convergence. The band has both a Gulf of Mexico connection and is also being aided by moisture from the Atlantic Ocean.

An additional one to two inches of rain will occur with this band (in less than 4 hours) as it lingers over New Jersey, before eventually pushing north and east. 19 of 21 counties in New Jersey are now under a flood warning of some sort, whether it is a general areal flood warning or a specific waterway flood warning. By sunrise, significant flooding will be in progress with low-lying areas, creeks, and streams and eventually this flooding will shift to the larger creeks and the rivers. Again, up in Northern New Jersey, flooding along the riverbeds has been in progress since the last heavy rain event.

For all the flood warnings: http://forecast.weather.gov/wwamap/wwatxtget.php?cwa=phi&wwa=flood warning

Wind Advisory and Heavy T-Storm Potential Late Tonight

A wind advisory was posted just a short time ago for Eastern and Southern New Jersey. A wind advisory means that sustained winds of 31 to 39 MPH or frequent wind gusts between 46 and 57 MPH are anticipated. Currently the advisory goes into the late evening hours. With the saturated ground, I have been emphasizing the potential for scattered trees to come down for days and this remains true with the soaking rain in progress and even heavier rain later tonight. Scattered power outages are expected. Wind gusts below the advisory criterion are even capable of bringing down trees with the soaked ground.

The computer model guidance continues to show a well-developed line of thunderstorms pushing through New Jersey between 11:00 p.m. and 3:00 a.m. with torrential rain. Based on the organization of these storms and strong winds aloft, I could even see the possibility of isolated damaging wind gusts with these storms.

A coastal flood warning has been issued for Northwestern Burlington, Camden, Gloucester, and Salem Counties. Tidal effects will aggravate the flooding along the Delaware River and along the coastline. Flood advisories and flood warnings are also posted for various communities and more will be added through the night I am sure. Low-lying areas and areas of poor drainage will flood first and then the water will enter and flood tributaries, creeks, and streams. Finally, the water will enter the major rivers and flood them. This will be a process, so the riverbeds may not flood from rain water until after the tidal flooding. The exception is the ongoing flooding for the Passaic River and also any riverbeds impacted by enhanced rains from thunderstorms which could result in flashier flooding.

Wind Advisory and Heavy T-Storm Potential Late Tonight

Image added shortly

A wind advisory was posted just a short time ago for Eastern and Southern New Jersey. A wind advisory means that sustained winds of 31 to 39 MPH or frequent wind gusts between 46 and 57 MPH are anticipated. Currently the advisory goes into the late evening hours. With the saturated ground, I have been emphasizing the potential for scattered trees to come down for days and this remains true with the soaking rain in progress and even heavier rain later tonight. Scattered power outages are expected. Wind gusts below the advisory criterion are even capable of bringing down trees with the soaked ground.

The computer model guidance continues to show a well-developed line of thunderstorms pushing through New Jersey between 11:00 p.m. and 3:00 a.m. with torrential rain. Based on the organization of these storms and strong winds aloft, I could even see the possibility of isolated damaging wind gusts with these storms.

A coastal flood warning has been issued for Northwestern Burlington, Camden, Gloucester, and Salem Counties. Tidal effects will aggravate the flooding along the Delaware River and along the coastline. Flood advisories and flood warnings are also posted for various communities and more will be added through the night I am sure. Low-lying areas and areas of poor drainage will flood first and then the water will enter and flood tributaries, creeks, and streams. Finally, the water will enter the major rivers and flood them. This will be a process, so the riverbeds may not flood from rain water until after the tidal flooding. The exception is the ongoing flooding for the Passaic River and also any riverbeds impacted by enhanced rains from thunderstorms which could result in flashier flooding.

Heavy Rain Moves In

Round one of the heavy rain is now taking over Southwestern New Jersey and Northwestern New Jersey. The very sharp cutoff line is slowly moving east-northeast and will take more and more areas into the rain as the morning and early afternoon progresses. Flood advisories have already been posted in advance of this line for the majority of New Jersey. A flood watch remains in effect for all 21 New Jersey counties. A coastal flood watch continues for Salem, Camden, Gloucester, and Northwestern Burlington Counties for areas along the Delaware River. Flood warnings remain in effect along the Passaic River basin where the flood waters never receded from the previous heavy rain event on Sunday.

East-southeast winds are so far sustained 15 to 25 MPH with gusts to about 35 MPH. As the low pressure areas strengthen and get closer to our region, the gradient should tighten further. The strongest winds will probably be late this afternoon and early this evening. Gusts should be pretty significant in our eastern counties for a time.

Both the GFS and NAM agree that there will be torrential rain falling in the evening or 12 hours from now.

3/9/2011 Extended Forecast: Flood Watch for All of NJ Now/ Strong Winds Expected

UPDATE @ 3:25 p.m.: Coastal Flood Watches have been posted for rather unusual, but significant tidal flooding along the Delaware River from Trenton and points south (let alone the rain flooding that may occur) for Northwestern Burlington, Camden, Gloucester, and Salem Counties...


The east-southeast wind is already cranking across our region today. Winds are sustained 10 to 15 MPH with frequent gusts of 20 to 30 MPH. These winds will only increase as the storm system evolves and moves closer to New Jersey. Vigorous negatively tilted trough and the position of the double-barrel low pressure areas will provide a nice setup for a strong fetch off the Atlantic Ocean and it will also provide a nice setup for strong wind gusts. There is no doubt this will be a windswept rainfall. A low center may exist across the Great Lakes with another forming along the Middle Atlantic. The one across the Middle Atlantic now appears it will move from east into the interior of Central Pennsylvania. This track will really bring in that stream of moisture. Meanwhile, high pressure will be to the north and east of Maine, and that will really work to tighten the gradient. I think the strongest wind gusts will be along our coastlines of Monmouth, Ocean, Southeastern Burlington, and Cape May Counties. Wind gusts past 55 MPH wouldn’t surprise me in these eastern counties during the height of the storm. They will drop off inland, but gusts will still be in excess of 40 MPH. There is the potential for structural damage to the trees and utility poles as the ground is so saturated that these wind gusts would be capable of knocking them down. . I think we will see so much rain that many of the weakened trees even without the wind could fall with the loosened soil. Of course flood waters can also be powerful enough to take down trees. The bottom line is strong easterly to southeasterly winds can be anticipated. Behind the departing system, northwesterly to westerly winds will occur on Friday. With a high pressure area building in, some more windy conditions can be expected, albeit not as intense. The previous Sunday storm, which did not have as strong of an east-southeast setup was able to get wind gusts to 56 MPH in New York City with widespread frequent gusts of around or above 40 MPH in New Jersey. So I do have reason to believe this will be a more impacting strong to high wind event.

Coastal flooding is going to be another concern with a persistent easterly flow. I think the water will pile up fairly well along our coastal communities. Widespread minor tidal flooding looks like a good bet. Some communities should experience moderate coastal flooding with my wind projections.

It appears as though the models want to now show to distinct rounds of heavy rainfall. The one round will be the moisture that streams up from Louisiana and the Florida Panhandle where tornado watches are currently in effect. Then the second round will be the evening and nighttime round which should put many low-lying areas and eventually waterways over their banks. In-between these rounds, there could even be a brief few hour lull (lighter rain?) in the action. Two to three inches of rain will likely fall from Thursday Afternoon into Friday Morning. Some areas will see localized amounts of four to six inches. Historic flooding is quite possible in Northern New Jersey where there is still ongoing flooding around the Passaic River Basin. The water levels will drop some, but perhaps not below flood stage prior to this event. Just imagine the rises in this area this time around as last time around we at least started below flood stage. Elsewhere, even if there is not ongoing flooding, should three inches fall, significant flooding is expected if the rainfall predictions are realized. Some of the flooding could be of moderate to major severity.

Tidal effects will aggravate the flooding along the Delaware River and along the coastline. I remain persistent that anyone living in an area that has flooded in the past few decades should prepare for flooding this go around. Move furniture to higher ground and have an evacuation plan in place. During the heavy rain, flooding in most areas will occur in low spots, around ditches, streets with areas of poor drainage, and at smaller creeks and streams. Then all that water on Friday will head towards the major creeks and major rivers. The rises here will be perhaps slow as it will take time for the runoff to make its way there, although if four inches of rain falls, a much faster rise can be expected, perhaps a flashier flood. The ground is so saturated that this rain cannot be absorbed. Trees are also not sucking in the water since there are no canopies to support. Numerous road closures are expected Thursday Night and Friday Morning.

Some isolated strong to severe thunderstorms cannot be ruled out. There appears to be some marginal instability. Some embedded thunderstorms will be associated with the low as it rides up the cold front. The convection will be mainly low-topped. Strong easterly winds may be enhanced by the convection just like last March when there was a few rumbles of thunder with the monster Nor’easter. With such a well-organized rain shield, detecting microbursts and weak tornadoes are difficult and it may not necessarily happen. It will all be about the parameters in place as the convection approaches from the south. The severe weather threat will be very limited, but not impossible. Any squall-lines that form to our south will have to be watched to see if they move into our region. Lightning could be limited with any convection that does form.

The flood watch now includes all of New Jersey’s 21 Counties. I couldn’t agree with this decision more. My wind forecast is presently more robust than the National Weather Service’s wind forecast. I am well aware. The stronger winds I am expecting is like a domino effect because it is related to tidal flooding in many aspects leading to a more dramatic coastal flood forecast from me. Eventually, in time, I suspect wind advisories and coastal flood statements will be issued for the eastern counties, even if it is issued during the storm. In the March 2010 storm, there were plenty of last minute issuances and upgrades. I have enough confidence in the overall setup to take a step away from cautiousness. If there are already 29 MPH gusts in interior Burlington County, how can I go wrong with the wind forecast during the peak of the storm?

Anyway, I will be updating the forecast again late tonight and all day tomorrow I will have extensive coverage.

GFS Shows Excessive Rainfall Event Thursday

GFS easily has 2 to 3 inches of rain, with spots seeing those 4 to 6 inch numbers.

GFS also shows a clear Atlantic fetch, with a pretty good wind from the east-southeast. It looks like some high winds...especially along the eastern counties such as Ocean and Monmouth Counties.

Flood Watch Issued for Thursday into Friday

The National Weather Service earlier this morning already placed a good portion of New Jersey under a flood watch from Thursday Morning into Friday Morning. Usually a watch would be issued slightly closer to the event. However, the model guidance continues to yield high confidence that another significant…if not excessive…rainfall event will impact the region on Thursday. The heaviest rain may wait until later on Thursday with cresting of waterways occurring approximately twelve to twenty-four hours later.

I am still confident in a widespread two to three inch rainfall, with locally higher amounts between four and six inches. I wouldn’t be surprised that some of sandier soil counties are added to the watch as the event gets closer. These rainfall amounts will result in moderate to major severity flooding. Some of the waterways in Northern New Jersey are still under a flood warning and some are awaiting a crest that will not occur until late tonight or Wednesday Morning at major flood stage. Since I do not believe these rivers will recover in time, historic flooding is a possibility for the Passaic River areas under the current warnings.

Flooding and Strong Wind Gusts

The entire state is under either a flood advisory or a flood warning. Rain continues to fall very heavily. Some portions of New Jersey have already seen two inches of rain in just less than three hours. I am watching a general area of showers that are already pushing north and east. But behind that is a small, miniature line of embedded thunderstorms moving from Burlington County in Ocean and Monmouth Counties. These storms could contain wind gusts past 40 MPH easily.



There could be a break in the activity for a few hours and then a squall-line could remain intact and move north and east towards New Jersey. This line has prompted a tornado watch box to our south and poses the risk for damaging wind gusts where it tracks. We will have to wait and see whether this will impact our region, and there is a chance it may. This band has formed with what we call a low-level confluence zone, right on the heels of cold air advection or the cold front. Remember, I have been warning that when the surface low passes and the cold front we may see the winds gust past 50 MPH. This could be the activity that does in fact cause the strong wind gusts.