Jump to content
  • Member Statistics

    17,586
    Total Members
    7,904
    Most Online
    23Yankee
    Newest Member
    23Yankee
    Joined

Hurricane Sandy - LIVE - Meteorological Discussion


Recommended Posts

Well the NHC report on Sandy is going to be extremely interesting. Wonder when they declare it post-tropical. I guess you could make the argument that it was PT at 5 pm on 10/29 based on lack of a core. I know it was right next to the coast at the time, and people might accuse them of trying to cover their butts since they never issued warnings, but I can understand the reasoning. I guess this debate will be argued in the Met community for a while because it is such a grey area since the storm was a hybrid and not purely tropical once it began interacting with the trough.

The 7pm Update wording was pretty specific, and issued prior to landfall:

POST-TROPICAL CYCLONE SANDY TROPICAL CYCLONE UPDATE

NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012

700 PM EDT MON OCT 29 2012

...SANDY BECOMES POST-TROPICAL...

...CENTER EXPECTED TO MAKE LANDFALL WITHIN THE NEXT HOUR OR SO...

and a bit later in the same Update:

NHC IS NOW DESIGNATING SANDY AS A POST-TROPICAL CYCLONE.

Link to comment
Share on other sites

  • Replies 1.3k
  • Created
  • Last Reply

I think it was pretty hard via sat image to see the center of circulation, especially if you were looking at WV or IR. On the visible images, you could see that some hours before landfall, the storm was starting to decouple. The lower levels were behaving like a tropical system should, but the upper levels were behaving extremely odd for a typical tropical storm.

You could from time to time see the 'lower level' eye peek out from the higher level clouds, which to me did seem to have a somewhat separate center of circulation. It looked more or less like a tropical system should, spinning the proper direction. The upper levels seemed to just be doing their own thing, often spinning in the opposite direction, or not spinning at all. I really wish I had saved one loop last night, as it REALLY showed this clearly.

This was a very ODD storm in many ways, but I've never really followed a storm like this that ran into a frontal boundary, so its new territory for me.

I'm hearing Sandy came ashore just south of AC, but it almost looks like there were two centers of circulation.

Link to comment
Share on other sites

The 7pm Update wording was pretty specific, and issued prior to landfall:

POST-TROPICAL CYCLONE SANDY TROPICAL CYCLONE UPDATE

NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012

700 PM EDT MON OCT 29 2012

...SANDY BECOMES POST-TROPICAL...

...CENTER EXPECTED TO MAKE LANDFALL WITHIN THE NEXT HOUR OR SO...

and a bit later in the same Update:

NHC IS NOW DESIGNATING SANDY AS A POST-TROPICAL CYCLONE.

Oh, they were clear about it. But sometimes they make postanalysis adjustments to the operational call.

Some things that makes me feel maybe this still was a tropical cyclone:

1) A large, warm eye was very apparent on IR imagery as it came ashore.

2) As large as it was, there seemed to be a centralized, somewhat symmetric core of strong winds. What really impressed me was how strong the winds were after the center passed and the NE quad was moving over the NYC area.

Link to comment
Share on other sites

I suppose I should ask here since more are paying attention to this thread... does anyone know the final, tropical, physical size of Sandy in comparison with Tip? I'm sure Tip edges out Sandy, but I'd like to know.

I believe Sandy was around 1100 miles at it's max, Tip was 1380 miles, still to see anything come close to matching Tip in size in the Atlantic Basin in October is simply astounding.

Link to comment
Share on other sites

Is there no room for it to be labeled a hybrid or transitioning system? Just curious.

Yeah, I know it can be reclassified post-event. Seems to be happening a lot lately smile.png

Edit: Just to make it clear, the "seems to be happening a lot lately" was joking comment re: the huge multi-decade reclassification study recently released, and not "they sure blew it this season and keep having to restate things"

Link to comment
Share on other sites

What frustrates me is that ASOS reports 2min sustained winds, which makes it a little harder to compare to the advisory 1 min winds.

Is there a place to get the 1-min data anywhere?

I checked NCDC but their archive stops at 10/1.

Wne through a more manual process on NNDC site,but for some reason their record for Islip stops in July of 2010 even though we know Islip is still actively reporting.

Link to comment
Share on other sites

REMNANTS OF SANDY ADVISORY NUMBER 37

NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD AL182012

1100 AM EDT WED OCT 31 2012

...WINDS...ACCUMULATING SNOWS...AND RAIN FROM THE REMNANTS OF

SANDY CONTINUE TO DIMINISH...

SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION

-----------------------------------------------

LOCATION...MULTIPLE CENTERS OF CIRCULATION IN ASSOCIATION WITH THE

REMNANTS OF SANDY CAN BE FOUND ACROSS THE LOWER GREAT LAKES.

WATCHES AND WARNINGS

--------------------

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

GALE WARNINGS REMAIN IN EFFECT FOR PORTIONS OF THE GREAT LAKES.

SMALL CRAFT ADVISORIES ARE IN EFFECT ALONG MUCH OF THE NORTHERN

MID-ATLANTIC AND NEW ENGLAND COASTS.

FLOOD WATCHES AND WARNINGS ARE IN EFFECT ACROSS NORTHERN NEW

ENGLAND...AND FLOOD WARNINGS REMAIN IN EFFECT FOR AREAS OF THE

NORTHERN MID-ATLANTIC STATES. LAKESHORE FLOOD WARNINGS HAVE BEEN

ISSUED FOR PORTIONS OF THE GREAT LAKES.

WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES REMAIN IN

EFFECT ALONG THE CENTRAL APPALACHIANS.

FOR INFORMATION SPECIFIC TO YOUR AREA...INCLUDING WATCHES AND

WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL

WEATHER SERVICE OFFICE AT WWW.WEATHER.GOV.

DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

AT 1100 AM EDT...1500 UTC...SANDY HAS WEAKENED...AND MULTIPLE

CENTERS OF CIRCULATION IN ASSOCIATION WITH THE REMNANTS OF SANDY

CAN BE FOUND ACROSS THE LOWER GREAT LAKES.

HAZARDS

-------

WIND...STRONG WINDS ACROSS THE GREAT LAKES WILL CONTINUE THROUGH

WEDNESDAY MORNING...BUT SHOULD DIMINISH IN THE AFTERNOON.

STORM SURGE...ELEVATED WATER LEVELS WILL CONTINUE TO SUBSIDE IN

PORTIONS OF THE UPPER AND MIDDLE CHESAPEAKE BAY DURING THE DAY.

FRESHWATER FLOOD WATERS ORIGINATING IN THE UPPER POTOMAC FROM THE

RAINS OF SANDY WILL CONTINUE TO IMPACT THE TIDAL

POTOMAC...RESULTING IN SIGNIFICANT FLOODING THROUGH FRIDAY

AFTERNOON.

DUE TO PERSISTENT NORTHERLY WINDS AND LARGE FETCH...COASTAL

FLOODING ALONG PORTIONS OF THE GREAT LAKES IS STILL POSSIBLE.

FOR STORM SURGE INFORMATION SPECIFIC TO YOUR AREA...PLEASE SEE

PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE.

RAINFALL...ADDITIONAL RAINFALL ACCUMULATIONS OF LESS THAN AN INCH

ARE EXPECTED IN THE EASTERN GREAT LAKES.

SNOWFALL...ADDITIONAL SNOWFALL ACCUMULATIONS OF 2 TO 4 INCHES ARE

EXPECTED IN THE MOUNTAINS OF WEST VIRGINIA INTO FAR WESTERN

MARYLAND AND SOUTHWEST PENNSYLVANIA.

NEXT ADVISORY

-------------

THIS WILL BE THE LAST PUBLIC ADVISORY ISSUED BY THE

HYDROMETEOROLOGICAL PREDICTION CENTER FOR THIS SYSTEM. PLEASE

REFER TO YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE FOR FURTHER

INFORMATION ON THIS STORM.

http://www.hpc.ncep.noaa.gov/tropical/tropical_advisories.php?storm=SANDY&adnum=37&dt=2012103115&status=remnants

Link to comment
Share on other sites

I guess people are learning what a wall of water can do! sorry to hear many of the public was thinking Irene.I had a feeling once this storm started spreading out it would take a longer time to wind down(Issac was some the same) and the trees up along the NE are not suited for the winds as they are along the S'er coastlines.God Speed on the recovery and been there and done that more than one wants.

Link to comment
Share on other sites

I believe most strong winds up that way are also from either Northwest or Northeast, so when winds switched to Southeast on Long Island, trees that might have been protected (or might have held sunny side foliage longer) would have been more vulnerable.

Anyone know how similar this was to mythic 1804 New England snowcane?

Link to comment
Share on other sites

Oh, they were clear about it. But sometimes they make postanalysis adjustments to the operational call.

Some things that makes me feel maybe this still was a tropical cyclone:

1) A large, warm eye was very apparent on IR imagery as it came ashore.

2) As large as it was, there seemed to be a centralized, somewhat symmetric core of strong winds. What really impressed me was how strong the winds were after the center passed and the NE quad was moving over the NYC area.

http://en.wikipedia.org/wiki/Sting_jet

Maybe?

Link to comment
Share on other sites

Some say MAUL, and some say sting jet. Are they the same thing?? What is a MAUL??

Someone could probably give a better answer, but my understanding is that the MAUL is the moist-adiabatic unstable layer. This was the mixed layer that developed near the surface that allowed the winds to mix down. I believe the sting jet would refer to the actual jet of enhanced winds and the MAUL is what it allowed to mix down in gusts.

Link to comment
Share on other sites

Someone could probably give a better answer, but my understanding is that the MAUL is the moist-adiabatic unstable layer. This was the mixed layer that developed near the surface that allowed the winds to mix down. I believe the sting jet would refer to the actual jet of enhanced winds and the MAUL is what it allowed to mix down in gusts.

Thank you!! That's makes a lot of sense.

Link to comment
Share on other sites

Someone could probably give a better answer, but my understanding is that the MAUL is the moist-adiabatic unstable layer. This was the mixed layer that developed near the surface that allowed the winds to mix down. I believe the sting jet would refer to the actual jet of enhanced winds and the MAUL is what it allowed to mix down in gusts.

*Moist absolutely unstable layer

"Moist absolute instability is a thermodynamic state

wherein a saturated layer of air exhibits a lapse rate

greater than moist adiabatic. Moist absolutely unstable

layers (MAULs) can form as a result of lifting an initially

sub-saturated, conditionally unstable environment. It is

traditionally argued that MAULs quickly overturn (i.e., in

a matter of minutes), since all parcels displaced

vertically within the layer will accelerate in the direction

in which they are displaced. Nevertheless, observations

and numerical simulations (e.g., Kain and Fritsch 1998,

Bryan and Fritsch 2000) suggest that MAULs may

persist for considerably longer periods of time (up to 30

min) and over large areas (tens of km across a squall

line and hundreds of km in the along-line direction)."

https://ams.confex.com/ams/pdfpapers/47608.pdf

Link to comment
Share on other sites

Thank you!! That's makes a lot of sense.

Moist Absolutely Unstable Layer, otherwise he's right. When that cold air wrapped around the circulation and occluded the eye, the winds got pretty fierce. A MAUL is freely convective. In other words, it will convect air on its own without any additional triggering mechanism. They're extremely effective at transferring momentum to the surface.

Link to comment
Share on other sites

*Moist absolutely unstable layer

"Moist absolute instability is a thermodynamic state

wherein a saturated layer of air exhibits a lapse rate

greater than moist adiabatic. Moist absolutely unstable

layers (MAULs) can form as a result of lifting an initially

sub-saturated, conditionally unstable environment. It is

traditionally argued that MAULs quickly overturn (i.e., in

a matter of minutes), since all parcels displaced

vertically within the layer will accelerate in the direction

in which they are displaced. Nevertheless, observations

and numerical simulations (e.g., Kain and Fritsch 1998,

Bryan and Fritsch 2000) suggest that MAULs may

persist for considerably longer periods of time (up to 30

min) and over large areas (tens of km across a squall

line and hundreds of km in the along-line direction)."

https://ams.confex.c...apers/47608.pdf

And in this case, it was extremely strong. Lapse rates approached dry adiabatic while saturated.

Link to comment
Share on other sites

I believe most strong winds up that way are also from either Northwest or Northeast, so when winds switched to Southeast on Long Island, trees that might have been protected (or might have held sunny side foliage longer) would have been more vulnerable.

Anyone know how similar this was to mythic 1804 New England snowcane?

Not that similar. I looked at the Ludlem track, It appears the Hurricane kicked east and a second ULL came in behind it and conected with the moist plume.

Similar to this.

http://www.meteo.psu.edu/~fxg1/NARR/1993/us1031.php

Or this.

http://www.meteo.psu.edu/~fxg1/NARR/2009/us1016.php

Except the fist southern stream SW was a hurricane in that case.

Link to comment
Share on other sites

Nice MAUL explanation(s). Wondering if any of the contributing mets would have time at some point to consolidate and/or expand on this, the sounding images, etc. into a MET101 thread.

Someone could probably give a better answer, but my understanding is that the MAUL is the moist-adiabatic unstable layer. This was the mixed layer that developed near the surface that allowed the winds to mix down. I believe the sting jet would refer to the actual jet of enhanced winds and the MAUL is what it allowed to mix down in gusts.

*Moist absolutely unstable layer

"Moist absolute instability is a thermodynamic state

wherein a saturated layer of air exhibits a lapse rate

greater than moist adiabatic. Moist absolutely unstable

layers (MAULs) can form as a result of lifting an initially

sub-saturated, conditionally unstable environment. It is

traditionally argued that MAULs quickly overturn (i.e., in

a matter of minutes), since all parcels displaced

vertically within the layer will accelerate in the direction

in which they are displaced. Nevertheless, observations

and numerical simulations (e.g., Kain and Fritsch 1998,

Bryan and Fritsch 2000) suggest that MAULs may

persist for considerably longer periods of time (up to 30

min) and over large areas (tens of km across a squall

line and hundreds of km in the along-line direction)."

https://ams.confex.c...apers/47608.pdf

Moist Absolutely Unstable Layer, otherwise he's right. When that cold air wrapped around the circulation and occluded the eye, the winds got pretty fierce. A MAUL is freely convective. In other words, it will convect air on its own without any additional triggering mechanism. They're extremely effective at transferring momentum to the surface.

And in this case, it was extremely strong. Lapse rates approached dry adiabatic while saturated.

Link to comment
Share on other sites

Nice MAUL explanation(s). Wondering if any of the contributing mets would have time at some point to consolidate and/or expand on this, the sounding images, etc. into a MET101 thread.

Someone could probably write an even more detailed post about momentum transfer, but Scott wrote a great one here: http://www.americanwx.com/bb/index.php/topic/37545-hurricane-sandy-obs-part-ii/page__st__245#entry1837402

And :lol: at me getting the acronym wrong. Whoops! lol.

Link to comment
Share on other sites

Hello , I had saved 1/2 increment water vapor images from the Full North Atlantic source on NOAA. (There are a few hours missing here and there from sleeping, however not as many as i had worried.)

Loop of wide range water vapor from 10/27 - 10/31

As per an earlier poster sharing an animated gif, this file is fairly large so do not click if you have a dialup connection!

It sheds a lot of light on the total dynamic at the time of Sandy. As an amateur there is a lot here that I don't fully understand but the size of the Sandy-system moisture once the systems merge is just shocking, all the way to the far northeast of the ocean. Do describe what you see, I am missing a lot of details!

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...