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PTC Matthew


PaEasternWX

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1 hour ago, RU4Real said:

I'm not comfortable with this analysis.

Littoral depth is a key factor in determining where and how a wave breaks but isn't particularly relevant to storm surge. The key elements of storm surge are fetch, direction and duration. All three of those elements are in play, here.

A storm surge accompanied by breaking surf is potentially more damaging to structures near the coastline, but the flooding damage caused by surge is independent of breaking surf.

For an analog, see the 18.5' of water that flooded into Sayreville NJ during Sandy. It came through Raritan Bay and up the Raritan River - several miles from the ocean and the nearest breaking wave. That flood event was all about fetch, direction and duration.

If the eye stays off shore, the winds will help keep down the storm surge. If it comes inland, it will be nasty.

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34 minutes ago, LakeEffectKing said:

After looking at the models and the conditions ahead for Matthew, I think there's a very good chance that he gets to 160mph over night...with pressures in th 925 range.... and right now to me it looks like landfall south of Daytona Beach by 50 miles or so...

My parents live in Boynton Beach, well away from the water thankfully. How bad will it get there do you think?

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3 minutes ago, jojo762 said:

Honestly no data that recon has found supports a 120mph hurricane attm. I'm going to take a solid guess that that'll change in the next few hours, but they just are not finding winds that strong...

So you're saying NHC forecast discussion 31 is incorrectly claiming 105kt/120mph?

Are there any pictures out there of the hurricane hunter plane-radar? Just wondering.

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1 hour ago, RU4Real said:

I'm not comfortable with this analysis.

Littoral depth is a key factor in determining where and how a wave breaks but isn't particularly relevant to storm surge. The key elements of storm surge are fetch, direction and duration. All three of those elements are in play, here.

A storm surge accompanied by breaking surf is potentially more damaging to structures near the coastline, but the flooding damage caused by surge is independent of breaking surf.

For an analog, see the 18.5' of water that flooded into Sayreville NJ during Sandy. It came through Raritan Bay and up the Raritan River - several miles from the ocean and the nearest breaking wave. That flood event was all about fetch, direction and duration.

The depth and shape of the ocean floor is a major factor in storm surge.  Long, shallow, gently sloping shelves lead to big storm surges (see the gulf coast).  Sharp dropoffs do not generate as big of storm surges (see hurricane andrew).    The se coast of florida features the latter.  The continental shelf drops off rapidly just a few miles from shore. However, that starts to change once you get up to about palm beach.  If you look at the coast of fl, right about here the coastline starts to bend and run back toward the nnw.  The continental shelf meanwhile continues north.  So after palm beach, the further north you go, the further offshore the dropoff is.  Therefore north florida will be more prone to surge than the SE coast.

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1 minute ago, Derecho! said:

Pressures stubbornly refusing to fall.  Pressure normally lags organization improvement, but I am having doubts at the RI hype for this evening. 

You will wake up a changed man and never doubt the posters at AMWX ever again ;-)

Seriously tho, you have some seasoned pros all on board here for RI overnight. Next several hours it will start. Convective flareups and towers now East and NE eyewall. It is starting. 

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Regardless of a surge, inlandish flooding could be pretty nasty just from drainage problems.

The St Johns northern flow from east-central FL will be fighting the southbound winds on Matthew's western side.  The eastbound stretch from Jacksonville to its mouth at Mayport will be getting the strongest westbound winds and pileup as Matthew approaches offshore. 

 

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11 minutes ago, Ralph Wiggum said:

You will wake up a changed man and never doubt the posters at AMWX ever again ;-)

Seriously tho, you have some seasoned pros all on board here for RI overnight. Next several hours it will start. Convective flareups and towers now East and NE eyewall. It is starting. 

Yu may have just taken the cake for the most weenie RI post I've seen in awhile. Not a bad thing, but it requires this.... :tomato:

It is one of hte more important tropical cyclone nights we've seen in a couple years, so I'm sure this thread will be lit up all night long. We do need to start to see some sort of pressure/wind reaction at some point. Not sure if the NOAA plane is having a few comms issues but their lack of dropsonde/vortex updates is annoying. Next AF aircraft is inbound so we'll get another perspective shortly. 

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17 minutes ago, Derecho! said:

Pressures stubbornly refusing to fall.  Pressure normally lags organization improvement, but I am having doubts at the RI hype for this evening. 

Once the thunderstorms wrap completely around the center and the eye starts to clear out via IR imagery the pressures will go down and depending on how quickly the center contracts will determine how low this can go

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1 minute ago, SharonA said:

Regardless of a surge, inlandish flooding could be pretty nasty just from drainage problems.

The St Johns northern flow from east-central FL will be fighting the southbound winds on Matthew's western side.  The eastbound stretch from Jacksonville to its mouth at Mayport will be getting the strongest westbound winds and pileup as Matthew approaches offshore. 

 

301 east is a concern for water and wind; Black Creek, Julington Creek and the Ortega River are also going to back up dramatically. San Marco (south side of Jax) is surely going to be under water. And the beat goes on ...

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8 minutes ago, Windspeed said:

RGTOP is great for peaking through the high over T anvil debris. You can clearly see the eye becoming better defined and the strong convection cell clusters going up in the eastern eyewall. This will begin pressure falls very shortly if not already.


d86f9cc4c00295c3d3d80a7ce30a4139.jpg

Tropical novice question.....I've seen it before and is often the sign of an intensifying/reorganizing system, but what is the technical term for the "rays" that are appearing along the N and NE side of the convection there? Is that just outflow? Or a function of the outflow? Is there a technical term for it?

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It seems to me that Matthew is so small and tight that these inner core dynamics kind of knock its center out of whack when you get these big thunderstorm flareups that we've seen over the past few hours.  I completely agree that the ingredients are in place, but until it develops organization around that center you can forget about RI.  That may not take long to happen, but it is definitely a necessary first step.

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