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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Quoting TomballTXPride:

No, it's not. Relax.
Your right, the one I quoted in post 284 is, my mistake. I could say similar things about florida being complacent and such too. There are always going to be some that don't follow evac order, those that want to and can't afford to, and those that can afford to have the best built homes fully able to weather a big storm and survive for weeks without power etc... but why would you wish a once in recorded history (so it's being called), or a 100 year, or 50 year storm on people as a wakeup call. The east coast has had what have been considered 100 year storms a lot (Isabel, Nor'Ida, Irene, to name a few).

Sometimes it's not being complacent or unprepared, but an act of nature that was unprecedented. People don't all know how to act or react, some people don't have help or can't afford to move away... they stay in their vulnerable houses, some go up to the attic when the water fills the rest of the house, and many become victims of the situation, whether the made the choice because they were complacent or unable to control the situation.

Lack of compassion in such situation is actually not unexpected by me in this country any longer. And while I won't agree with my neighbors on politics, as with the last few storm and flooding events, I will offer my hand in assisting them and put my needs second.

Actually, I don't care if you have no compassion, but don't wish death, destruction, and hardship on people because they "weren't prepared enough" for your opinion.
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0z models are in. Two main changes: One is that overall agreement is better than it has been. The other is that the general trend this cycle vs. 12z and 18z was a bit of a northward shift as the NHC track now lies closer to the western edge of consensus:

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Quoting TropicalAnalystwx13:

Well, uhm, actually, it does in normal hurricanes.

Well, uhm, Sandy is different...
Member Since: March 16, 2012 Posts: 127 Comments: 7958
Quoting KeyWestbeachcomber:
KORI WHATEVER You may be a regular..to me you are TROLLING a TROLL and a jerk...I will come back when you are TROLLING elsewhere goodnight to THE REGULARS who ARE regular. I apologise. With Respect,Beachcomber


If I wanted to troll, I could come up with a much more subtle approach than this.
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No SFMR measurements on the most recent refresh of recon information on Google Earth.
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KORI WHATEVER You may be a regular..to me you are TROLLING a TROLL and a jerk...I will come back when you are TROLLING elsewhere goodnight to THE REGULARS who ARE regular. I apologise. With Respect,Beachcomber
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Quoting wxchaser97:

Sandy will be a 70-65mph TS at 11pm, just saying. It doesn't matter if it doesn't add up, it isn't math class. Since rain rates are low in some areas found with high winds and non are flagged they are legit.

Well, uhm, actually, it does in normal hurricanes.
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Quoting wxchaser97:

Sandy will be a 70-65mph TS at 11pm, just saying. It doesn't matter if it doesn't add up, it isn't math class. Since rain rates are low in some areas found with high winds and non are flagged they are legit.


OK......and explain to me how flight level winds can be 26 mph and surface winds can be 70 mph. Thanks.
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Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 26th day of the month at 23:27Z
Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)
Storm Number & Year: 18L in 2012
Storm Name: Sandy (flight in the North Atlantic basin)
Mission Number: 12
Observation Number: 12
A. Time of Center Fix: 26th day of the month at 22:50:05Z
B. Center Fix Coordinates: 27°21'N 77°11'W (27.35N 77.1833W)
B. Center Fix Location: 158 miles (255 km) to the N (4°) from Nassau, Bahamas.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 45kts (~ 51.8mph)
E. Location of the Estimated Maximum Surface Wind: 51 nautical miles (59 statute miles) to the N (356°) of center fix
F. Maximum Flight Level Wind Inbound: From 90° at 48kts (From the E at ~ 55.2mph)
G. Location of Maximum Flight Level Wind Inbound: 88 nautical miles (101 statute miles) to the N (358°) of center fix
H. Minimum Sea Level Pressure: 966mb (28.53 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 6°C (43°F) at a pressure alt. of 3,656m (11,995ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 14°C (57°F) at a pressure alt. of 3,658m (12,001ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 8°C (46°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Wind, Pressure and Temperature
N. Fix Level: Other - Not surface, 1500ft, 925mb (if vortex is newer than about mid 90's; see note for more), 850mb, 700mb, 500mb, 400mb, 300mb or 200mb
O. Fix Determined By / Fix Level (Undecoded): 1 / 2 nm
Remarks Section - Remarks That Were Decoded...
Sea Level Pressure Extrapolation From: 12,000 feet
Remarks Section - Additional Remarks...
MAX OUTBOUND FL WIND AND MAX FL WIND 52 KT S QUAD 22:59:18Z
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Oct 27, 2012 00Z

850 mb vorticity


500 mb vorticity


200 mb vorticity


image credits: Univ of Wisconsin real-time products

Velly intelestink.
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Quoting AllStar17:


Flight level winds at 26 mph.

SFMR at 70 mph.

Doesn't add up at all.

Sandy will be a 70-65mph TS at 11pm, just saying. It doesn't matter if it doesn't add up, it isn't math class. Since rain rates are low in some areas found with high winds and non are flagged they are legit.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
Quoting Bayside:

Actually, this is the flamebait that I hope you get banned for.
Really? You had to post that twice? Quit with the cute arguments.
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288. bwat
Quoting AllStar17:


Flight level winds at 26 mph.

SFMR at 70 mph.

Doesn't add up at all.
Could it be that with the weakening and transition to extra tropical the winds aren't mixing down the the surface very well just yet? A lot of time until landfall, and more favorable baroclinic conditions to come once the storm gets further north.
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Quoting AllStar17:


Flight level winds at 26 mph.

SFMR at 70 mph.

Doesn't add up at all.

When you see the contaminated flag let me know.
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Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 27th day of the month at 00:29Z
Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)
Storm Number & Year: 18L in 2012
Storm Name: Sandy (flight in the North Atlantic basin)
Mission Number: 12
Observation Number: 21
A. Time of Center Fix: 26th day of the month at 23:52:49Z
B. Center Fix Coordinates: 27°25'N 77°14'W (27.4167N 77.2333W) (View map)
B. Center Fix Location: 163 miles (262 km) to the N (2°) from Nassau, Bahamas.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 40kts (~ 46.0mph)
E. Location of the Estimated Maximum Surface Wind: 79 nautical miles (91 statute miles) to the SE (132°) of center fix
F. Maximum Flight Level Wind Inbound: From 234° at 57kts (From the SW at ~ 65.6mph)
G. Location of Maximum Flight Level Wind Inbound: 69 nautical miles (79 statute miles) to the SE (132°) of center fix
H. Minimum Sea Level Pressure: 971mb (28.67 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 12°C (54°F) at a pressure alt. of 3,659m (12,005ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 13°C (55°F) at a pressure alt. of 3,660m (12,008ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 9°C (48°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: Other - Not surface, 1500ft, 925mb (if vortex is newer than about mid 90's; see note for more), 850mb, 700mb, 500mb, 400mb, 300mb or 200mb
O. Fix Determined By / Fix Level (Undecoded): 1 / 6 nm
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 57kts (~ 65.6mph) in the southeast quadrant at 23:35:53Z
Maximum Flight Level Wind Outbound: 52kts (~ 59.8mph) in the northwest quadrant at 0:07:32Z
Maximum Flight Level Temp: 15°C (59°F) which was observed 29 nautical miles (33 statute miles) to the SE (128°) from the flight level center
Remarks Section - Additional Remarks...
STRONG BANDING NW
Member Since: September 16, 2005 Posts: 0 Comments: 3174
NOAA's link for storm tides and storm surge.
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Quoting TropicalAnalystwx13:

Recon is finding a bunch of 60-65 knot surface winds in the rain shield to the northwest of the center. It's not typical to use surface winds when they are higher than the flight-level, but then again, Sandy is not a normal hurricane. None of them have been marked as contaminated, and that would explain why it wasn't reduced to a TS at the intermediate advisory.


Flight level winds at 26 mph.

SFMR at 70 mph.

Doesn't add up at all.
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Quoting AllStar17:


60 kts? I haven't seen anything above 50 kts, really.

Recon is finding a bunch of 60-65 knot surface winds in the rain shield to the northwest of the center. It's not typical to use surface winds when they are higher than the flight-level, but then again, Sandy is not a normal hurricane. None of them have been marked as contaminated, and that would explain why it wasn't reduced to a TS at the intermediate advisory.
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Quoting KoritheMan:


The way people in general work, is that they become complacent if it's not happening to them. With so many "false alarms" in recent years for New England (Isabel hit North Carolina and moved pretty much into the Ohio Valley, so she doesn't really count), they are ill-prepared for a storm of this magnitude. While Sandy will no doubt cause significant damage anyway, it's going to be maximized by complacency and lack of preparation.

Unfortunately, that's how we as people work. Therefore, an occasional hurricane or two is necessary to get us back into "storm alert".


this is flamebait and I hope for a ban.
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Quoting TropicalAnalystwx13:
Recon data supports an initial intensity of 60 knots at 03z. Sandy is weakening (for the time being) in terms of winds, but very slowly. This is not the time to become complacent, as re-intensification is expected on Sunday and Monday as it passes over the Gulf Stream in a moderate wind shear environment with strong baroclinic support.


60 kts? I haven't seen anything above 50 kts, really.
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Quoting guygee:

You can see she still has a vigorous surface circulation and as she is pulling away from the ULL she is even starting to wrap some convection closer to her core. Reports of Sandy's Demise Have Been Much Exaggerated.


They forget that the core of the westerlies often permeates through this region.
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Recon data supports an initial intensity of 60 knots at 03z. Sandy is weakening (for the time being) in terms of winds, but very slowly. This is not the time to become complacent, as re-intensification is expected on Sunday and Monday as it passes over the Gulf Stream in a moderate wind shear environment with strong baroclinic support.
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Recon continuing to find nothing very impressive in terms of winds with Sandy.
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You can see she still has a vigorous surface circulation and as she is pulling away from the ULL she is even starting to wrap some convection closer to her core. Reports of Sandy's Demise Have Been Much Exaggerated.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
Quoting TropicalAnalystwx13:

'Hi Kori, remember me? The storm that caused over $16 billion in damage in the USA last year?



Irene apparently wasn't enough, since I've talked to a ton of people who think that the local meteorologists are needlessly hyping this storm. The same thing went down with Isaac on the Gulf Coast. Few people in Louisiana were actually prepared for what happened.
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Link
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Even if it is taking dry air, people are preparing. Store almost ran out of bread
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Quoting KoritheMan:


At the risk of sounding inhumane, I hope their fears come to reality. The northeast United States needs a wake up call. Irene was nothing compared to what it could have been. In terms of tropical threats, their last real threat was Bob, and that was 21 years ago.

'Hi Kori, remember me? The storm that caused over $16 billion in damage in the USA last year?'

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Quoting AllStar17:


????????????????????


The way people in general work, is that they become complacent if it's not happening to them. With so many "false alarms" in recent years for New England (Isabel hit North Carolina and moved pretty much into the Ohio Valley, so she doesn't really count), they are ill-prepared for a storm of this magnitude. While Sandy will no doubt cause significant damage anyway, it's going to be maximized by complacency and lack of preparation.

Unfortunately, that's how we as people work. Therefore, an occasional hurricane or two is necessary to get us back into "storm alert".
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Quoting Chicklit:


she's post mortem


Hey Chicklit, looks, in this case, can be VERY deceiving! Sandy is transitioning.... and the "typical" things we look at for a true tropical storm do not apply.

Think about it, with the center exposed, and dry air abound, under a normal tropical storm, pressures would be increasing...... but in this case, the latest recon reports indicate the pressures are dropping.....

The best way to look at this storm overall, is to imagine you have a tropical storm enveloped by a nor' easter...... which is basically what we will have.....

The will be an immense debate coming a few days from now, and it will consist of when, and what moment, do you declare Sandy "non-tropical", or "post tropical". I actually look forward to this debate, because in this particular setup, to say is rare, well, it is extremely rare. So current understandings, definitions, and such will be tested!

I also look forward to seeing just how low the central pressure of Sandy will get...... I don't think 950mb at landfall is out of the question...... and many models predict lower, although I question their accuracy......

Like I have said before, I hate to see the loss of life, and property damage, but from a strict weather point of view..... I look forward to watching what could be a once in a lifetime storm unfold! If you are north of the landfall location, and near the coast, prepare for flooding like you have never seen before!
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266. beell

AMSU Cross Section


AMSU-A (Channel 5) representing mid level temps.

Both from 19:54Z. A few hours old but not a significant change in structure, shear, or dry air (opinion) since then.

Univ of Wisconsin - AMSU Tropical Cyclone Home Page
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Quoting KoritheMan:


At the risk of sounding inhumane, I hope their fears come to reality. The northeast United States needs a wake up call. Irene was nothing compared to what it could have been. In terms of tropical threats, their last real threat was Bob, and that was 21 years ago.


????????????????????
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Quoting GTcooliebai:
I'm thinking Subtropical as most of the convection is sheared away and that is where the highest winds would be, not the center.
She can be warm-core and still have convection sheared away and higher winds away from the center, it is not a contradiction.
Member Since: September 16, 2005 Posts: 0 Comments: 3174
Here in NJ....all that my ShopRite had left was 3 cans of lousy dogfood, some plastic spoons, and a seeded roll. I went with the roll.

Public is being scared to death.
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After being stationary for the last several hours, it looks like she's about to start the move back to the north-northeast. The low over Cuba that was pulling her northwest is being absorbed so we'll see. I'd still don't know where the low is that will turn it to the northwest and into New Jersey though.



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Recon hasn't observed even any flight level winds above 60 kts yet. Highest flight level so far has been 50 kts.
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258. Zappy
Quoting KoritheMan:


It won't. Don't even think that.

Can you be cynical but optimistic?

Anyway, it's almost guaranteed that most in CT will lose power... Last year, I resorted to snail mail for communications. That was fun.
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Station 41009 (LLNR 840) - CANAVERAL 20 NM East of Cape Canaveral, FL
28.523° N 80.184° W (28°31'22" N 80°11'3" W)



Buoy 41009 was down for quite awhile but looks like they brought her back up just in time.
Member Since: September 16, 2005 Posts: 0 Comments: 3174

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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.