Sandy remains a hurricane, slowly leaving the Bahamas

By: Angela Fritz , 9:28 PM GMT on October 26, 2012

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Reuters reports that the death toll from Sandy in the Caribbean is now up to 41 people as Hurricane Sandy continues its track toward the U.S. East Coast this afternoon, slowly leaving the Bahamas. States of Emergency have been declared in North Carolina, Virginia, Maryland, and New York. The hurricane is just barely still a Category 1 with surface winds of 75 mph and a minimum central pressure of 971 mb. Ocean buoys off the coasts of Florida and the Carolinas are recording sustained winds of around 45 mph this afternoon, with gusts steadily increasing and now up to 60 mph. Sandy's rainfall, which is limited to the north and northeast parts of the storm, is reaching eastern Florida, though most of it is staying offshore.

Satellite loops show an asymmetric Sandy, with almost all of the thunderstorm activity on its north side. The hurricane still has a very clear center of surface circulation which you can see on visible and infrared loops. Though the hurricane is leaving the influence of an upper level low pressure area over western Cuba, water vapor imagery shows a large area of dry air being pulled into the storm from the south, which is leading to the lack of thunderstorm activity and contributing to the weakening that Sandy is experiencing right now. The hurricane's tropical storm-force winds now extend 240 miles from the center, and could grow to 400 miles from the center by the time it reaches the East Coast.


Figure 1. Visible/infrared satellite image of Sandy as it leaves the Bahamas this afternoon. The mid-latitude trough, which Sandy will interact with over the next few days, is seen approaching from the northwest. The cold front associated with this trough is draped from upstate New York south to Louisiana, and appears as a line of clouds draped across the Midwest and South in this image.

Forecast For Hurricane Sandy

As a tropical cyclone approaches land, the worst storm surge is almost always where the winds are blowing from ocean to shore, where the wind pushes the water toward and onto the shore. In the case of Sandy's potential track, this region is on the north side of the center. In this morning's GFS scenario, Sandy's center passes over eastern Long Island, Connecticut, and Rhode Island. This would result in the highest surge north of New York City: Rhode Island, Massachusetts, New Hampshire, and possibly Maine. The ECMWF forecast from this morning is a bit further to the south. It's suggesting Sandy's center will meet land in New Jersey. This scenario opens up New York City, Long Island, Connecticut, Rhode Island, and southern coastal Mass. to the largest surge. In general, the places that will avoid the largest storm surge are those that are south of where the center of the storm makes landfall. The National Hurricane Center's forecast is similar to the ECMWF, but most importantly, its forecast is also to not focus on the exact point of landfall because of the size of the storm, and that widespread impact is expected.

The Mid-Atlantic and Northeast coasts should be prepared for a storm surge no matter their exact location. A large portion of the coast will feel the impact of up to 60 mph winds and heavy rain. According to the most recent H*Wind analysis from the Hurricane Research Division is that storm surge has a destructive potential of 4.8 out of 6.0, which is a slight increase from previous analyses. Wind damage potential is holding steady around 2.3 out of 6.0. NOAA's HPC is forecasting rainfall totals of 5 to 10 inches in the Mid-Atlantic and Northeast, and possibly more in coastal locations close to the core of the storm. Widespread power outages from Maine south to Virginia are likely, due to the combination of long-lived gale-force winds, leaves on trees, and rain that will moisten the soil and possibly increase the chances of falling trees. Snow in the Appalachians is also possible as the intense moisture meets the cold air being pulled south by the mid-latitude trough.


Figure 2. Departure of sea surface temperature from average for the Atlantic shows a large area of unusually warm waters up to 9°F above average off the U.S. mid-Atlantic coast.

Sandy to feed off near-record warm waters off the mid-Atlantic coast
During September 2012, ocean temperatures off the mid-Atlantic coast in the 5x10° latitude-longitude box between 35 - 40°N, 65 - 75° W were 2.3°F (1.3°C) above average, according to the UK Met Office. This is the 2nd greatest departure from average for ocean temperatures in this region since reliable ocean temperature measurements began over a century ago (all-time record: 2.0°C above average in September 1947.) These unusually warm waters have persisted into October, and will enable Sandy to pull more energy from the ocean than a typical October hurricane. The warm waters will also help increase Sandy's rains, since more water vapor will evaporate into the air from a warm ocean. I expect Sandy will dump the heaviest October rains on record over a large swath of the mid-Atlantic and New England.

Hurricane rains and climate change
Hurricanes are expected to dump 20% more rain in their cores by the year 2100, according to modeling studies (Knutson et al., 2010). This occurs since a warmer atmosphere holds more water vapor, which can then condense into heavier rains. Furthermore, the condensation process releases heat energy (latent heat), which invigorates the storm, making its updrafts stronger and creating even more rain. We may already be seeing an increase in rainfall from hurricanes due to a warmer atmosphere. A 2010 study by Kunkel et al. "Recent increases in U.S. heavy precipitation associated with tropical cyclones", found that although there is no evidence for a long-term increase in North American mainland land-falling tropical cyclones (which include both hurricanes and tropical storms), the number of heavy precipitation events, defined as 1-in-5-year events, more than doubled between 1994 - 2008, compared to the long-term average from 1895 - 2008. As I discussed in a 2011 post "Tropical Storm Lee's flood in Binghamton: was global warming the final straw?", an increase in heavy precipitation events in the 21st Century due to climate change is going to be a big problem for a flood control system designed for the 20th Century's climate.


Figure 3. Time series of the 15-yr running average (plotted at the end point of the 15-yr blocks) of the tropical cyclone Heavy Precipitation Index (red) and the associated 15-yr total of U.S. landfalling hurricanes from Atlantic HURDAT hurricane data base, from 1895 - 2008 (blue). Note the steep rise in heavy precipitation events from tropical cyclones over the past 20 years, which has not been accompanied by a corresponding increase in landfalling hurricanes. Image credit: Kunkel et al., 2010, Geophysical Research Letters.

Angela Fritz and Jeff Masters

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656. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #43
TYPHOON SON-TINH (T1223)
15:00 PM JST October 27 2012
====================================

SUBJECT: Category Three Typhoon In South China Sea

At 6:00 AM UTC, Typhoon Son-Tinh (965 hPa) located at 17.0N 109.7E has 10 minute sustained winds of 70 knots with gusts of 100 knots. The cyclone is reported as moving west northwest at 13 knots.

Dvorak Intensity: T4.5

Storm Force Winds
=================
60 NM from the center

Gale Force Winds
================
210 NM from the center

Forecast and Intensity
========================

24 HRS: 19.0N 106.1E - 60 knots (CAT 2/Severe Tropical Storm) Gulf of Tonkin
48 HRS: 20.3N 105.2E - 35 knots (CAT 1/Tropical Storm) Overland Vietnam
72 HRS: 21.2N 104.7E - Tropical Depression Overland Vietnam
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The Euro makes landfall to the south of NYC but a little quicker than the GFS. It is along the lines of my forecast track.
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Most models now on board with an area of sub-freezing cold air at the 850 mbar level being brought to the SOUTHERN side of Sandy (PA to WV) as it weakens over the lower Great Lakes region.
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Good morning from Europe.

Daily Mail:

East Coast braces for '30 year storm': State of emergency declared as Hurricane Sandy targets New York (and it even looks scary from space)

Up to 400,000 New Yorkers could be evacuated as city declares state of emergency, which means state will have access to federal funding

Subways facing possible shutdown - the second time in history

Sandy could be 'worst case' superstorm, more powerful than Irene

Could cause up to $1billion worth of damage

As many as 43 people reported dead across Caribbean as super storm barrels north

More
Member Since: October 25, 2008 Posts: 52 Comments: 5680
Well, I guess Sandy's a tropical storm again, per ATCF.
Member Since: September 7, 2006 Posts: 89 Comments: 2653
To confirm the new convection, however it is not strong yet:


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Quoting wxchaser97:

Actually there can't be a subtropical hurricane, it is not a term recognized by meteorologists. I think Sandy is still tropical as recon has still continued to find a warm core storm with a closed circulation.


Convection has also formed closer to the center, which is an indication that she's still fully tropical.
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Quoting Bobbyweather:
Sandy is subtropoical according to SSD. Could it possibly be a subtropical hurricane? (There has never been such a phenomenon yet, was there?)

Actually there can't be a subtropical hurricane, it is not a term recognized by meteorologists. I think Sandy is still tropical as recon has still continued to find a warm core storm with a closed circulation.
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The merging of the systems begins: The outcome can only be predicted and the models are better than they have ever been.


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Quoting AstroHurricane001:
While Sandy is slated to bring hundred-year floods to the Mid-Atlantic States through Pennsylvania, over half of the CONUS remains in drought:



It would take a widespread 10 to 15 inches of rain for the affected area to get a 100-year flood.
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Blog update on Sandy.
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Sandy is subtropoical according to SSD. Could it possibly be a subtropical hurricane? (There has never been such a phenomenon yet, was there?)
Member Since: September 7, 2006 Posts: 89 Comments: 2653
Quoting ConnecticutWXGuy: this is what I expect, for the moment


Personally, I think those values are bit too conservative. I think the heavier winds will be spread out much more, same with the rain.
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Quoting ConnecticutWXGuy:
btw I find it hard to believe that there are people STILL asking how Sandy's pressure is still falling even though it no longer appears to be a tropical system. Anyone who has been paying attention to this blog or TV has already had the explanation drilled into their heads, I would think.


WXGuy, I agree which is some of the reasons I was asking the insurance question. The media now has this hyped a bit but it does not look good for NJ and NE in general in the next few days.
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Shear is starting to drop as the front gets closer. I wonder if this is expected to continue, as Levi forecast?

Levi, where are you when we need you? Isn't it still daylight up in Alaska?

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While Sandy is slated to bring hundred-year floods to the Mid-Atlantic States through Pennsylvania, over half of the CONUS remains in drought:

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Quoting NJ2S:
ok so TWC just circled the entire state of NJ as likely ground zero YET no emegency declaration....has anyone gotten christie out of the chinese buffet and into emergency management!


Christie's actually trying to get English style bookmaking legal in Jersey, so maybe he's waiting to see what kind of odds the bookies post.
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btw I find it hard to believe that there are people STILL asking how Sandy's pressure is still falling even though it no longer appears to be a tropical system. Anyone who has been paying attention to this blog or TV has already had the explanation drilled into their heads, I would think.
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637. NJ2S
ok so TWC just circled the entire state of NJ as likely ground zero YET no emegency declaration....has anyone gotten christie out of the chinese buffet and into emergency management!
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Quoting MelbourneTom:


Thank you for a response. Yes I know it varies from state to state. The +/- 1 week is a new one to me. So I think you are saying that where you are at that you are cvovered as long as you got insurance more than one week before this storm was named. It still sounds to me like a lot of people could have an up and coming nightmare, I guess I just dont know because of the various state differences.

hopefully folks up that way may have some sort of wind rider available on their homeowners but regardless there is going to be alot of finacial damages to contend with cant imagine ins company are any better up there than here at settling claims.
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this is what I expect, for the moment
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Quoting BosGuy:
Just to show my question about Boston isn't all about me, follow this link to the Boston Globe and see a maximum wind prediction of...28 mph.

That's what's being communicated to the public.


Channel 7 says 50 to 60 mph winds! Also the track isn't set yet!
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Quoting lat25five:


Insurance varies state to state per state regulators. I know down here its+ or - one week of tropical advisories. Just replacement mine this summer had to get timing right to roll-over w/o lapse in coverage.


Thank you for a response. Yes I know it varies from state to state. The +/- 1 week is a new one to me. So I think you are saying that where you are at that you are cvovered as long as you got insurance more than one week before this storm was named. It still sounds to me like a lot of people could have an up and coming nightmare, I guess I just dont know because of the various state differences.
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Quoting OracleDeAtlantis:
Interesting similarities ... especially if you suspect there was a baroclinic transfer of energy with this one.

I've read that this storm is suspected to have been a CAT 4 when it made landfall, and intensified dramatically as it did so.





Yes, but that was in August. Sandy will be hitting in October, making the situation that much more remarkable.
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Interesting similarities ... especially if you suspect there was a baroclinic transfer of energy with this one.

I've read that this storm is suspected to have been a CAT 4 when it made landfall, and intensified dramatically as it did so.



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Quoting MelbourneTom:
I had no response to my insurance question. If the NHC keeps Sandy classified as a hurricane will the people in NE be covered? I suspect most people there do not carry seperate hurricane coverage like we do in Florida.


Insurance varies state to state per state regulators. I know down here its+ or - one week of tropical advisories. Just replacement mine this summer had to get timing right to roll-over w/o lapse in coverage.
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Wave heights of 25+ coupled with high tide could cause some major beach erosion and structural damage. I doubt buildings from Delaware on up practice the same mitigation methods as coastal buildings in the Carolinas.
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Quoting KoritheMan:


Unlike you I have some degree of self-control, so I'm almost done with mine.

Oh really, I didn't say I didn't even have to look at Sandy to forecast her going out to sea...

I already finished my graphics and I have a quarter of the writing done.
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Quoting leftlink:


This is known as "constant wind intensification" (CWI) and it happened with Isaac as well. The storm is using its drop in central pressure drop to increase in size, rather than increase its wind speed.

But he was asking how its possible for the pressure to fall in the absence of t-storm activity? Surface pressure falls occur from upper divergence...a tropical cyclone does this by latent heat release driven upper anticyclone...a non-tropical system does this by tapping into split flow or accelerational divergence east of an upper trough or along a jet stream...Sandy is doing more of the non-tropical method which is why she's down to 969 mb...
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I had no response to my insurance question. If the NHC keeps Sandy classified as a hurricane will the people in NE be covered? I suspect most people there do not carry seperate hurricane coverage like we do in Florida.
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Quoting KoritheMan:


Where's your post for tonight?

Another question, where is your post for tonight? I am working on mine.
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Quoting KoritheMan:


Where's your post for tonight?

Well...I post in the mornings now...so the next one is for Sat morning....
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Quoting cheetaking:
969 mb? What the hell? Satellite appearance has been getting worse and worse all day, its entire south side is ingesting dry air, it no longer has any eyewall whatsoever, and there's not even any significant heavy thunderstorms left. And yet the pressure just dropped by 2 mb. Unbelievable.


This is known as "constant wind intensification" (CWI) and it happened with Isaac as well. The storm is using its drop in central pressure drop to increase in size, rather than increase its wind speed.
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Quoting NCHurricane2009:
I have done some detailed tropical Atlantic update posts for those trying to understand what Sandy has been doing day-by-day...hopefully this is educational for folks interested in meteorology and wanting to learn the mechanics of this epic storm...

My Post from Fri Morning

My post from Thu Morning

Wed Morning

Tue Morning


Where's your post for tonight?
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I have done some detailed tropical Atlantic update posts for those trying to understand what Sandy has been doing day-by-day...hopefully this is educational for folks interested in meteorology and wanting to learn the mechanics of this epic storm...

My Post from Fri Morning

My post from Thu Morning

Wed Morning

Tue Morning
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Quoting AussieStorm:


Link


Thanks very interesting. Just when you think things couldnt get any worse the hybrid version has another trick up her sleeve.
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616. Skyepony (Mod)
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Just took out dogs for little late night stroll,been clearing up nicely down here ingest of dry air really saved us. With almost full moon sky is really bright and low level clouds are just ripping out of the NW. Scattered clouds are really low level but they are moving across the night sky at an incredible speed aloft. Very eriee.
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O_o

Look at post 588! Event the NWS is spelling doom! Wow!
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Member Since: September 30, 2007 Posts: 9 Comments: 15932
Quoting CoopsWife:


Oh, we'll figure something out - though it might be a bit unconventional, LOL. I think I may just go ahead and de-winterize the camper. That would allow an extra 40 gallons drinking/wash water, plus a little hot water heater, stove, etc. Full water tanks will help with the weight, too. :) I think I'll flush the pipes and go ahead and fill the fresh tanks, just in case.... (arrgggh - it such a PAIN to winterize.)



Stay safe. I know what you mean, I think I would just dewinterize and have that option, at a minimum for the hot water if your house doesn't have propane heat (gas/electric you could lose). Take care, hope to hear all was ok after this is over.
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Quoting Gustavike:
Someone know where is the archive of this map?:


Gus I did not carry this out to the end result but I think this might be the path you are looking for.

Link

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Snow Accumulation 0 -> 84hrs


Member Since: September 30, 2007 Posts: 9 Comments: 15932
Just to show my question about Boston isn't all about me, follow this link to the Boston Globe and see a maximum wind prediction of...28 mph.

That's what's being communicated to the public.
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Quoting lat25five:


Aussie

First Ive ever heard of this sting jet phenom.can you elaborated?


Link

Member Since: September 30, 2007 Posts: 9 Comments: 15932
Quoting weathercurious25:
Hello everyone,this is my first post over to the blog,i found it some days ago.

I a couple of questions, i have been reading all 6 days now and i am wondering.I live in the DC area, and i read all about a monster storm and everything.

My first question is, how bad is that going to be for DC? I mean windwise mostly, and if except that there are more things that i should be worried about.

My second question is,i am thinking of 3 options right now,the one is staying here and hope that things will be ok at the house i am living at, the second is to go to the family house which would be 105 miles southwest from here(and has a basement)and third and not so reasonable right now,go for some days to really southwest 420 from here to NC.

I would appreciate if people won't make fun of me,i haven't been in such a situation before and i don't know what to expect.

Thanks a lot for any answer in advance.


As long as you stay inside, the storm should not pose any threat to your life.

Whether you stay in DC or go to your family home, a worst case scenario would be being without power for 4-5 days--that's a long inconvenient time. It's a matter of if you feel secure in DC where your at and who is with you being without power that long, or if you'd feel safer at home.
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Hello weathercurious25: just keep in post of what going on. Just make sure if you travel go go the safest way.im pretty sure your home will be ok. Far as the storm concern where your at, let see how it pans out, tune to your local news. Thanks
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.