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Significant Ocean Storm March 5-7 2013 Discussion Part II


earthlight

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Final-Snow-Map.png

I think the "storm surge up to 8 feet!" is irresponsible, without explaining what that means.  Yes, tides will likely be 8 feet above the mean low tide level, but high tide is usually 5 feet above low tide and the 8 feet being referred to is relative to mean low tide, meaning the "storm surge" is really 3 feet above mean high tide, which is what people care about.  Nobody cares if the high tide is normal - they care how much higher it will get than a normal high tide.  Here's what the NWS said in the AFD...

 

OUR LOCAL IN HOUSE TIDAL DEPARTURE PROCEDURES

ARE GIVING US A TIDAL DEPARTURE OF AROUND 2.5 FEET WITH THE STARTING

WEDNESDAY AFTERNOON HIGH TIDE CYCLE. THIS WAS USING A 50/50 NAM AND

GFS BLEND. NOTING THAT THE "NORTHWARD" DRIFT OF THE MODELS HAS NOT

STOPPED AND USING A STRAIGHT (NORTHERNMOST FOR THIS RUN) GFS

SOLUTION WOULD TAKE US CLOSE TO MODERATE TIDAL FLOODING THRESHOLD

WITH THE WEDNESDAY AFTERNOON HIGH TIDE.

 

A 2.5-3.0 foot storm surge above mean high tide is considered minor to moderate and is in line with many past nor'easters and a completely different animal than the 10-12 foot storm surge seen for Sandy - lots of people out there already freaking out about how these numbers are reported in the coastal flood advisory by the NWS (where they report 8 feet above mean lower low water, which is the same as mean low tide, really) - way too confusing for laypeople (and Steve, obviously). 

 

 AT...SANDY HOOK... NEW JERSEY... HIGH TIDE WILL OCCUR AT 258

  PM WEDNESDAY WITH A FORECAST TIDE LEVEL OF 7.5 TO 8.0 FEET

  ABOVE MEAN LOWER LOW WATER. HIGH TIDE WILL THEN OCCUR AT 331

  AM THURSDAY WITH A FORECAST TIDE LEVEL NEAR 8.0 FEET ABOVE

  MEAN LOWER LOW WATER.

 

 

The NWS briefing package deck shows this in a nice graphic in the 6th slide. 

 

http://www.erh.noaa.gov/er/phi/briefing/packages/current_briefing.pdf

 

Thank you for this.  All day long at work, I have been talking about this misunderstanding of feet above mean low water and feet above normal.  There are numerous outlets calling for tides of 6 to 8 feet above normal.  It is simply applying the wrong base and is very misleading

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The Nam is just now beginning to pick up on the inverted trough, let's see if that can trend even stronger as much uncertainty remains with the first part tomorrow. 

 

I mean it is pretty ghastly to see how far apart the models are less than 24 hrs before the storm arrives. I just can't wait to see what surprises the gfs brings. Watch it completely whiff. 

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Location, Location, Location

 

You do remember that it corrected itself and gave LI 30" of snow and not NJ. It's all about where everything sets up.

 

 

Yup I wrote that I remember going bananas that it shows huge totals around here  than Moved all those Totals North and East like 6-12 hours later. Difference with that storm Conn. to Boston were predicted to get the Jackpot for Days before that never really changed except a Fluke Nam run or two. If Nam still shows something similar tonight than it may be one to something since it has been showing a big hit in this area for 24 hrs now(4 or 5 runs in a row).

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The Nam is just now beginning to pick up on the inverted trough, let's see if that can trend even stronger as much uncertainty remains with the first part tomorrow. 

 

I mean it is pretty ghastly to see how far apart the models are less than 24 hrs before the storm arrives. I just can't wait to see what surprises the gfs brings. Watch it completely whiff. 

 

 

I think it comes back closer to the Nam (just a guess) if it whiffs than that would be comical.

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HI-RES NAM is pretty much always in lock-step with the regular NAM, no? 

 

Sometimes it is different like a couple of weeks back when the regular NAM had a moderate snow here and it correctly stayed south. Also with the blizzard, it held serve while the regular NAM had a few OTS runs.

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The Nam is just now beginning to pick up on the inverted trough, let's see if that can trend even stronger as much uncertainty remains with the first part tomorrow. 

 

I mean it is pretty ghastly to see how far apart the models are less than 24 hrs before the storm arrives. I just can't wait to see what surprises the gfs brings. Watch it completely whiff. 

It's a very tough situation to model with so many moving parts. I think the GFS could be right but I still call BS on how it gets there.

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wrt to the hi res being lock step with the 12km nam it is mostly true yes, but as we've seen several times this year not always. With the blizzard it was the 4km nam which picked up on how the storm would evolve first, and it's simulated radar was literally spot on. I remember discussing how good it was after the storm ended.

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ECM says Boston gets 2 feet and NYC almost nothing.

 

NAM says NYC gets 2 feet and Boston almost nothing.

 

LOL.

 

BTW, completely disagree that this is a good run for New England. Gets much too toasty on the NAM in the mid levels. 

WOW - looking at the skew-t's for JFK it remains below 0C at all levels sans maybe the surface thru hr 48.

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Wow. What are we going to call this one? The NAM shows the coastal amping up with the kicker not being a kicker anymore as mentioned earlier, and then the norlun trough continues the party. Maybe the NAM is onto something in regards to this being either extremely potent on both ends (coastal/norlun) or on one end with the Norlun (Euro/somewhat GFS). 

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i have a feeling the goofus is going to be better looking. Might be wishful thinking though

I'm also thinking that, at the very least I would like to see it take a step toward the NAM not away from it.

 

- Its the 18z so lets see if my theory that it usually telegraphs shifts int he right direction holds.

- I didn't like that none of the 12z ensembles members showed a nice hit though

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