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hurricane sandy thread #3


forkyfork

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^Was unaware it was higher than that at the battery at one point. That's still well over flood stage though.

This was put out 7:45pm

Note the higher numbers were for tomorrow evening..

Coastal Flood Warning

Expires 3:00 PM EDT on October 30, 2012

Statement as of 7:45 PM EDT on October 28, 2012

... NY Harbor water levels for Monday morning...

Coastal... ... ... ... time of... ... forecast total... ..Flood... ..

Location... ... ... ..high Tide... ..Water level... ... .category..

... ... ... ... ... ... ... ... ... ... ... ..(Mllw)... ... ... ... ... ... ..

The Battery NYC... ..831 am... ... ... 8.7... ... ... ... .Moderate..

Bergen Point NY... ..830 am... ... ... 9.4... ... ... ... .Moderate..

... Western l.I. Sound water levels for Monday morning...

Coastal... ... ... ... time of... ... forecast total... ..Flood... ..

Location... ... ... ..high Tide... ..Water level... ... .category..

... ... ... ... ... ... ... ... ... ... ... ..(Mllw)... ... ... ... ... ... ..

Kings Point NY... ... 1159 am... ... ..12.8... ... ... ... moderate..

Lattingtown NY... ... 1158 am... ... ..12.9... ... ... ... moderate..

Stamford CT... ... ... 1131 am... ... ..12.6... ... ... ... moderate..

Bridgeport CT... ... .1128 am... ... ..12.1... ... ... ... moderate..

New Haven CT... ... ..1128 am... ... ..11.0... ... ... ... moderate..

... Eastern l.I. Sound water levels for Monday morning...

Coastal... ... ... ... time of... ... forecast total... ..Flood... ..

Location... ... ... ..high Tide... ..Water level... ... .category..

... ... ... ... ... ... ... ... ... ... ... ..(Mllw)... ... ... ... ... ... ..

New London CT... ... .928 am... ... ... 6.3... ... ... ... .Moderate..

... South Shore bays water levels for Monday morning...

Coastal... ... ... ... time of... ... forecast total... ..Flood... ..

Location... ... ... ..high Tide... ..Water level... ... .category..

... ... ... ... ... ... ... ... ... ... ... .(mllw/ngvd)... ... ... ... ... ... ..

E Rockaway Inlet NY.814 am... ... ... 7.5/6.0... ... ... Moderate..

Freeport gage NY... .858 am... ... ... 6.9/6.1... ... ... Major... ..

Jamaica Bay NY... ... 840 am... ... ... 9.2/7.0... ... ... Moderate..

Point Lookout... ... .741 am... ... ... 7.6/6.5... ... ... Moderate..

... Ocean water levels for Monday morning...

Coastal... ... ... ... time of... ... forecast total... ..Flood... ..

Location... ... ... ..high Tide... ..Water level... ... .category..

... ... ... ... ... ... ... ... ... ... ... ..(Mllw)... ... ... ... ... ... ..

Montauk Point NY... .903 am... ... ... 6.0... ... ... ... .Moderate..

... NY Harbor water levels for Monday evening...

Coastal... ... ... ... time of... ... forecast total... ..Flood... ..

Location... ... ... ..high Tide... ..Water level... ... .category..

... ... ... ... ... ... ... ... ... ... ... ..(Mllw)... ... ... ... ... ... ..

The Battery NYC... ..813 PM... ... ... 11.7... ... ... ... .Major... .

Bergen Point NY... ..814 PM... ... ... 12.3... ... ... ... .Major... .

... Western l.I. Sound water levels for Monday night...

Coastal... ... ... ... time of... ... forecast total... ..Flood... ..

Location... ... ... ..high Tide... ..Water level... ... .category..

... ... ... ... ... ... ... ... ... ... ... ..(Mllw)... ... ... ... ... ... ..

Kings Point NY... ... 1227 am... ... ..16.6... ... ... ... .Major... .

Lattingtown NY... ... 1205 am... ... ..16.7... ... ... ... .Major... .

Stamford CT... ... ... 1201 am... ... ..16.4... ... ... ... .Major... .

Bridgeport CT... ... .1158 PM... ... ..15.9... ... ... ... .Major... .

New Haven CT... ... ..1157 PM... ... ..15.3... ... ... ... .Major... .

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I believe 9.5 was what the Battery reached during Irene. I wonder why the values were scaled back?

They just released the new Coastal Flood Warning for the area and it has the evening water level at the battery as 11.7 still, which is 2 feet above the Irene maximum. The problem with that is that, during Irene the water came within 0.5 to 1 feet of flooding the subway, so there is serious concern that the subway could flood this time.

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I have a bit of a bone to pick/question about these surge graphs. I hear people (ex: just read Tom Skilling's update about the surge) saying there is a "9-11 foot surge" coming. Is the tidal flow really include in the surge? Otherwise, compared to 'normal' high tide, the surge is "only" 4-6 feet. How exactly is the surge being defined here?

Well, during Irene, places in Brooklyn that are 8' ASL were underwater. I am at 13' ASL and did not receive any water even though I was 0.5 mile away from the water. So a forecast of 10-12' surge would be 7-9' feet higher than that 3' Irene surge. I don't know if I will be okay this time.

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I have a bit of a bone to pick/question about these surge graphs. I hear people (ex: just read Tom Skilling's update about the surge) saying there is a "9-11 foot surge" coming. Is the tidal flow really include in the surge? Otherwise, compared to 'normal' high tide, the surge is "only" 4-6 feet. How exactly is the surge being defined here?

"9-11 foot surge" is a misnomer - it's 9-11 feet above Mean Low Low Water, which implies an actual surge of 4-6 feet.

Mt. Holly's forecast for Sandy Hook to get around 12 feet MLLW includes a surge of around 7 feet. Record MLLW there is, I believe, 10.1 - during Donna.

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Storm Surge: 9-11'+ High Tide: 4.8'

I have a bit of a bone to pick/question about these surge graphs. I hear people (ex: just read Tom Skilling's update about the surge) saying there is a "9-11 foot surge" coming. Is the tidal flow really include in the surge? Otherwise, compared to 'normal' high tide, the surge is "only" 4-6 feet. How exactly is the surge being defined here?

The 9-11 feet is total storm tide...surge plus tide. If you look at Upton's table, they are giving total tide values above MLLW.

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"9-11 foot surge" is a misnomer - it's 9-11 feet above Mean Low Low Water, which implies an actual surge of 4-6 feet.

Mt. Holly's forecast for Sandy Hook to get around 12 feet MLLW includes a surge of around 7 feet. Record MLLW there is, I believe, 10.1 - during Donna.

Thanks, this is what I was getting at - the fact that it is a misnomer. Without clarification it sounds like there's going to be an actual rise of 9-11 feet, which is wholly different than 4-6 feet (which is still bad, of course).

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Thanks, this is what I was getting at - the fact that it is a misnomer. Without clarification it sounds like there's going to be an actual rise of 9-11 feet, which is wholly different than 4-6 feet (which is still bad, of course).

Exactly, and I wish this were better clarified by the media (or whoever it is that may be relaying the info). An actual surge of 9-11 feet would be absolutely horribly terrible, of course! 4-6 is definitely bad enough.

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Exactly, and I wish this were better clarified by the media (or whoever it is that may be relaying the info). An actual surge of 9-11 feet would be absolutely horribly terrible, of course! 4-6 is definitely bad enough.

Part of the problem is people are so used to Gulf of Mexico surge forecasts, where they barely have tides.

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But how does the MLLW relate to elevation? I am at 13' ASL in the south shore of Brooklyn. During Irene, places 8' ASL flooded out. Would I be safe this time?

I'm pretty sure that elevation above sea level is based on mean sea level (MSL), which is the average water level over some long period of time. So, MSL incorporates all low and high tides (and everything in between). I don't know this for sure, but I'd imagine MSL is roughly the average of MLLW and MHHW (or MLW and MHW).

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Part of the problem is people are so used to Gulf of Mexico surge forecasts, where they barely have tides.

True - surge height and tide height there are pretty much the same. Nothing like the 5-foot tidal differences during spring tides on the East Coast (or the much larger differences in the Bay of Fundy).

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So my actual 13' ASL is really 15' MLLW since MSL is 2'. Upton predicts a MLLW of 12' so am I cutting it too close? I don't know if their forecast includes 20-foot waves or not? If not, then how would that impact my location? Thanks for all the feedback in here, guys! smile.png

That's right! I would say you aren't cutting it close unless you are on or only have a bottom floor - then I'd suggest relocating. Waves will only have a significant impact immediately next to bodies of water - and big waves only immediately next to the ocean, as in within a few blocks, if the ocean overtops dune systems (which is quite rare; oftentimes surge comes in through storm drains, back bays, etc.).

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ALHurricane: In the actual CSW by Upton, they state "6-11 feet above astronomical tides." I am not sure if they mean above ground level.

The problem is (and this isn't the first time) that not everybody is referring to the same datum level. NHC is definitely referring to above ground level. Way too confusing for all involved, IMO.

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That's right! I would say you aren't cutting it close unless you are on or only have a bottom floor - then I'd suggest relocating. Waves will only have a significant impact immediately next to bodies of water - and big waves only immediately next to the ocean, as in within a few blocks, if the ocean overtops dune systems (which is quite rare; oftentimes surge comes in through storm drains, back bays, etc.).

I am in a house with only 1 level and a basement, which is a bungalow 1.5 mile inland above Coney Island. And I am not sure the Battery's forecast MLLW correlates well to my area.

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I am in a house with only 1 level and a basement, which is a bungalow 1.5 mile inland above Coney Island. And I am not sure the Battery's forecast MLLW correlates well to my area.

That far inland, I'd say you're okay. The Battery probably correlates decently well, though I think surge could be higher at the Battery due to the funneling effect - especially with the big SE winds that Upton is forecasting to push through the harbor after the center passes.

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Took a look at Stevens Institute of Technology's model for using the NYHOPS model for surge. So far surge at the battery is about a foot higher than forecast... although their forecast is initially lower than NOAA's but winds up the same. Seems to be on track with NOAA's model projection.

http://hudson.dl.ste...ml?station=N017

For all the confusion, the 'actual' surge seems forecast to be 7 feet at Bergen Point and 6 feet at The Battery.

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