March 10 - March 11 Redux Event

[IsentropicLift]

yeah my bad

[Rtd208]

HPC QPF Days 4-5.

[Mikehobbyst]

Does this event have chance to produce 45-50 knot wind gusts towards the end of the week with tremendous gradient, negative tilted characteristic with some cut-off tendancies? Looks like last years damaging wind event last March that ravaged SE NYC and LI. Getting gusts to 35-40 knots on southern LI now with current event. Lots of wind advisory warning events happening the last years and very recently.

[tornadojay]

0Z GFS Ensemble sphagetti plots still showing a large number of members with a potential cutoff.

[tornadojay]

0Z Euro has fairly impressive QPF just north of us.. It looks like it has slowed down the progression as well.. it is showing a rather deep, negatively tilted trof.

[tornadojay]

12Z operational GFS and it's ensemble members are in remarkable agreement on another heavy rain event later in the week.. although not necessarily advertising a cutoff anymore, it is a slow moving, dynamic system that looks to dump several inches of additional rainfall.

[Dark Energy]

The kicker short wave kills the cutoff low. Will still be another soaker tho.

[Rtd208]

Looks like there is the potential for a serious flood threat to develop later this week with another 1-3" of rain expected on top of already saturated ground and the rivers and streams already running high from yesterdays heavy rain.

[IsentropicLift]

Latest GFS continues to bring the idea of 3" + of rain over areas already flooded. This would probably rival the records if this were to occur.

[dbc]

Latest GFS continues to bring the idea of 3" + of rain over areas already flooded. This would probably rival the records if this were to occur.

Perhaps for March. We have had way more rain in shorter periods of time than this will be at other times of the year.

[Chris L]

Perhaps for March. We have had way more rain in shorter periods of time than this will be at other times of the year.

Indeed.

Hurricane Floyd of 1999. Tropical Storm Bertha of 1996.

Even the July 2006 Severe Wx had ton of wind and rain.

[Zir0b]

Perhaps for March. We have had way more rain in shorter periods of time than this will be at other times of the year.

this will be a big deal for the rivers/streams in NJ

[IsentropicLift]

We had some convection drop 6" of rain in a very short period last summer. The point I was trying to make is, it doesn't usually occur when the rivers and streams are already well above normal levels. Some of the slower rivers such as the Passaic could still be above flood stage when the rain hits. The river in my town which hit major stage today will probably be at least at action stage. The lower areas of my town begin to flood well before actual flood stage is hit. Also the word is, the dam in Pompton Lakes is holding back a tremendous amount of water. Right now its partially open and the water is hitting the bridge. If we get that rain, and they open of the dam completely we should easily rival last March. We fell less than a foot short today of top 5 crests all time.

[tornadojay]

6Z ensemble members have reverted back to a cutoff again... should be an interesting system to follow

[hudsonvalley21]

6Z ensemble members have reverted back to a cutoff again... should be an interesting system to follow

06z GFS has a soaker up here at KSWF.

http://www.meteor.iastate.edu/~ckarsten/cobb/cobb.php?model=gfsm&site=kswf

[dbc]

We had some convection drop 6" of rain in a very short period last summer. The point I was trying to make is, it doesn't usually occur when the rivers and streams are already well above normal levels. Some of the slower rivers such as the Passaic could still be above flood stage when the rain hits. The river in my town which hit major stage today will probably be at least at action stage. The lower areas of my town begin to flood well before actual flood stage is hit. Also the word is, the dam in Pompton Lakes is holding back a tremendous amount of water. Right now its partially open and the water is hitting the bridge. If we get that rain, and they open of the dam completely we should easily rival last March. We fell less than a foot short today of top 5 crests all time.

Very true but there has been way worse/more impacting than this and last March for that matter at other times of the year. I recall either in October 2002 or October 2003 or maybe both we had way more rain than this with way more flooding issues in shorter periods of time with lakes/rivers already in/above or around flood stage. Maybe not for Pompton Lakes but for many more areas in New Jersey.

October 2002:

http://lwf.ncdc.noaa...ideprank_pg.gif

October 2003:

http://lwf.ncdc.noaa...ideprank_pg.gif

October 2005 too:

http://lwf.ncdc.noaa...ideprank_pg.gif

[tornadojay]

12Z NAM hammers us with heavy rainfall through hour 66 and it doesn't look like it's done yet

[tmagan]

This is a very serious situation, no two ways about it.

[tornadojay]

NAM QPF has 2.5-3.0 inch bullseye over western Bergen, Passaic and northern Morris counties, with pretty much 2 - 2.5 for the rest of NYC metro.

[IsentropicLift]

Very true but there has been way worse/more impacting than this and last March for that matter at other times of the year. I recall either in October 2002 or October 2003 or maybe both we had way more rain than this with way more flooding issues in shorter periods of time with lakes/rivers already in/above or around flood stage. Maybe not for Pompton Lakes but for many more areas in New Jersey.

October 2002:

http://lwf.ncdc.noaa...ideprank_pg.gif

October 2003:

http://lwf.ncdc.noaa...ideprank_pg.gif

October 2005 too:

http://lwf.ncdc.noaa...ideprank_pg.gif

I can only speak for my river, but last March, we hit #2 all time after the Noreaster which gave as ~ 4" of rain. The main culprit was not only because of the heavy amounts of rain but also because of runoff from snowmelt in the higher terrain. OEM told us beforehand they estimated that the snowpack was still holding ~9 of water in areas like West Milford and that the reservoirs were near full. Going into that event however, the Pompton river and most other parts of the Passaic river basin were near normal to slightly above normal levels. About ten days or so after that, we got another ~2.5" rainfall system and we hit moderate flood stage. The Passaic river took the brunt of that system.

This is a different setup since the rivers will have much less time to recover. You have to understand how the system works to really see why we could reach record flood stage at the end of this week.

The Ramapo River and the Pequannock River both feed into the Pompton River north of Pompton Plains and then the Pompton River flows into the Passaic River near Two-Bridges Road in Lincoln Park.

The Passaic River is still rising and is not forecast to reach crest until sometime tomorrow. Then, it will most likely still be well above flood stage by the time the rain begins sometime on late Wed or early Thursday. Once the Passaic River flow gets going, it builds up a resistance to the Pompton River at two bridges. It's like taking two streams of water, if you have one stream at 150GPM and then you point a second stream at the first one flowing at 100GPM the second stream is going to be re-directed instead of bisecting the faster flowing stream.

What ends up happening, is that an artificial dam forms at the intersection of the Pompton and Passaic rivers. In extreme cases, it can actually cause reverse flow.

The end result is that when the Passaic river is already well above normal levels, the other tributary rivers are much more vulnerable because the water has no place to go.

Throw in the facts that the reservoirs are near full, that all rivers will be well above normal by the time the precip begins, a completely saturated ground, that some models are forecasting even more rainfall than the last event and that there is now snow up in Orange County where all the runoff begins and you have a recipie for catastrophic flooding.

This is not a forecast, people just need to understand the seriousness of what is likely to occur should the forecasted rainfall totals verify. We nearly reached top 5 all time status yesterday with only 3.5" of rain, and only slightly above normal river levels going in.

[riverrat]

I can only speak for my river, but last March, we hit #2 all time after the Noreaster which gave as ~ 4" of rain. The main culprit was not only because of the heavy amounts of rain but also because of runoff from snowmelt in the higher terrain. OEM told us beforehand they estimated that the snowpack was still holding ~9 of water in areas like West Milford and that the reservoirs were near full. Going into that event however, the Pompton river and most other parts of the Passaic river basin were near normal to slightly above normal levels. About ten days or so after that, we got another ~2.5" rainfall system and we hit moderate flood stage. The Passaic river took the brunt of that system.

This is a different setup since the rivers will have much less time to recover. You have to understand how the system works to really see why we could reach record flood stage at the end of this week.

The Ramapo River and the Pequannock River both feed into the Pompton River north of Pompton Plains and then the Pompton River flows into the Passaic River near Two-Bridges Road in Lincoln Park.

The Passaic River is still rising and is not forecast to reach crest until sometime tomorrow. Then, it will most likely still be well above flood stage by the time the rain begins sometime on late Wed or early Thursday. Once the Passaic River flow gets going, it builds up a resistance to the Pompton River at two bridges. It's like taking two streams of water, if you have one stream at 150GPM and then you point a second stream at the first one flowing at 100GPM the second stream is going to be re-directed instead of bisecting the faster flowing stream.

What ends up happening, is that an artificial dam forms at the intersection of the Pompton and Passaic rivers. In extreme cases, it can actually cause reverse flow.

The end result is that when the Passaic river is already well above normal levels, the other tributary rivers are much more vulnerable because the water has no place to go.

Throw in the facts that the reservoirs are near full, that all rivers will be well above normal by the time the precip begins, a completely saturated ground, that some models are forecasting even more rainfall than the last event and that there is now snow up in Orange County where all the runoff begins and you have a recipie for catastrophic flooding.

This is not a forecast, people just need to understand the seriousness of what is likely to occur should the forecasted rainfall totals verify. We nearly reached top 5 all time status yesterday with only 3.5" of rain, and only slightly above normal river levels going in.

Good explanation. You really have to live in the area to get a good feel on how the rivers will react in any given situation. I have been living near the two bridges going on 25 years and have seen a lot. This situation, if forecasts become reality, will get real ugly really fast.

[IsentropicLift]

I've lived here since 89 and I'm on the fire department in the lower half of town. I forgot to give props to Mt Holly for going ahead and issuing the flood watch already to raise awarness. The GFS came in very similar to the NAM. This is going to be a scary situation.

[dbc]

I can only speak for my river, but last March, we hit #2 all time after the Noreaster which gave as ~ 4" of rain. The main culprit was not only because of the heavy amounts of rain but also because of runoff from snowmelt in the higher terrain. OEM told us beforehand they estimated that the snowpack was still holding ~9 of water in areas like West Milford and that the reservoirs were near full. Going into that event however, the Pompton river and most other parts of the Passaic river basin were near normal to slightly above normal levels. About ten days or so after that, we got another ~2.5" rainfall system and we hit moderate flood stage. The Passaic river took the brunt of that system.

This is a different setup since the rivers will have much less time to recover. You have to understand how the system works to really see why we could reach record flood stage at the end of this week.

The Ramapo River and the Pequannock River both feed into the Pompton River north of Pompton Plains and then the Pompton River flows into the Passaic River near Two-Bridges Road in Lincoln Park.

The Passaic River is still rising and is not forecast to reach crest until sometime tomorrow. Then, it will most likely still be well above flood stage by the time the rain begins sometime on late Wed or early Thursday. Once the Passaic River flow gets going, it builds up a resistance to the Pompton River at two bridges. It's like taking two streams of water, if you have one stream at 150GPM and then you point a second stream at the first one flowing at 100GPM the second stream is going to be re-directed instead of bisecting the faster flowing stream.

What ends up happening, is that an artificial dam forms at the intersection of the Pompton and Passaic rivers. In extreme cases, it can actually cause reverse flow.

The end result is that when the Passaic river is already well above normal levels, the other tributary rivers are much more vulnerable because the water has no place to go.

Throw in the facts that the reservoirs are near full, that all rivers will be well above normal by the time the precip begins, a completely saturated ground, that some models are forecasting even more rainfall than the last event and that there is now snow up in Orange County where all the runoff begins and you have a recipie for catastrophic flooding.

This is not a forecast, people just need to understand the seriousness of what is likely to occur should the forecasted rainfall totals verify. We nearly reached top 5 all time status yesterday with only 3.5" of rain, and only slightly above normal river levels going in.

Very interesting and complex setup in that area. Like I said not all areas of New Jersey will have these issues and back in October of 2002, 2003 and 2005, perhaps your area did not flood severely due to how things developed. I can guarantee that what you see happen will be much more dangerous than what will happen in other areas during this upcoming storm. However, my main point is that back in those past Octobers I mentioned other areas had as dangerous problems as your area may now see but those same areas will not be compromised this time around as much as they were then. Not to say it won't cause some issues but not as extreme as those Octobers for many people.

[BlueSkiesFading]

I hate living along the Passaic River . Luckily, it takes a lot to for it to overflow in my area, but 3-4" might do the trick. Last March we came close. Water started pouring up from the sewers and flooding my street, but it receeded just in time before it could cause any real damage. I feel for those that live near the Willowbrook Mall in Wayne and Little Falls. If the forecasts come to fruition, there WILL be serious flooding in those areas.

Before Floyd, I rarely remember the Passaic River flooding. Now it seems like an annual occurrence.

[gkrangers]

I hate living along the Passaic River . Luckily, it takes a lot to for it to overflow in my area, but 3-4" might do the trick. Last March we came close. Water started pouring up from the sewers and flooding my street, but it receeded just in time before it could cause any real damage. I feel for those that live near the Willowbrook Mall in Wayne and Little Falls. If the forecasts come to fruition, there WILL be serious flooding in those areas.

Before Floyd, I rarely remember the Passaic River flooding. Now it seems like an annual occurrence.

I live on the dry side of town, I think.

[Guest Patrick]

Fantastic explanation of the unique interaction between the Pompton & Passaic Rivers.

I crown thee, "King of Hydrology"

I can only speak for my river, but last March, we hit #2 all time after the Noreaster which gave as ~ 4" of rain. The main culprit was not only because of the heavy amounts of rain but also because of runoff from snowmelt in the higher terrain. OEM told us beforehand they estimated that the snowpack was still holding ~9 of water in areas like West Milford and that the reservoirs were near full. Going into that event however, the Pompton river and most other parts of the Passaic river basin were near normal to slightly above normal levels. About ten days or so after that, we got another ~2.5" rainfall system and we hit moderate flood stage. The Passaic river took the brunt of that system.

This is a different setup since the rivers will have much less time to recover. You have to understand how the system works to really see why we could reach record flood stage at the end of this week.

The Ramapo River and the Pequannock River both feed into the Pompton River north of Pompton Plains and then the Pompton River flows into the Passaic River near Two-Bridges Road in Lincoln Park.

The Passaic River is still rising and is not forecast to reach crest until sometime tomorrow. Then, it will most likely still be well above flood stage by the time the rain begins sometime on late Wed or early Thursday. Once the Passaic River flow gets going, it builds up a resistance to the Pompton River at two bridges. It's like taking two streams of water, if you have one stream at 150GPM and then you point a second stream at the first one flowing at 100GPM the second stream is going to be re-directed instead of bisecting the faster flowing stream.

What ends up happening, is that an artificial dam forms at the intersection of the Pompton and Passaic rivers. In extreme cases, it can actually cause reverse flow.

The end result is that when the Passaic river is already well above normal levels, the other tributary rivers are much more vulnerable because the water has no place to go.

Throw in the facts that the reservoirs are near full, that all rivers will be well above normal by the time the precip begins, a completely saturated ground, that some models are forecasting even more rainfall than the last event and that there is now snow up in Orange County where all the runoff begins and you have a recipie for catastrophic flooding.

This is not a forecast, people just need to understand the seriousness of what is likely to occur should the forecasted rainfall totals verify. We nearly reached top 5 all time status yesterday with only 3.5" of rain, and only slightly above normal river levels going in.

[dbc]

I live on the dry side of town, I think.

If you are well away from Riverside Ave you probably encounter less issues.

[tornadojay]

the long-term agreement amongst ensemble members is pretty amazing. The sphagetti plots show unbelievable agreement essentially all the way through this Sunday. What that says to me is that the models must have an excellent handle on that enourmous ridge over the Atlanctic.... with that basically stuck in place, you basically take out a huge piece of potential variability in the different model solutions.

[CooL]

the long-term agreement amongst ensemble members is pretty amazing. The sphagetti plots show unbelievable agreement essentially all the way through this Sunday. What that says to me is that the models must have an excellent handle on that enourmous ridge over the Atlanctic.... with that basically stuck in place, you basically take out a huge piece of potential variability in the different model solutions.

2 months too late

interesting nonetheless however, maybe models are built to handle certain patterns better then the fragile and explosive patterns like we had in dec/jan..

[IsentropicLift]

The GFS has been locked on this upcoming event for over a week now. It's amazing how consistent its been in terms of QPF and placement.