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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HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 415
MILES...
665 KM. NOAA BUOY 41010 RECENTLY REPORTED SUSTAINED WINDS
OF 49 MPH...79 KM/H...AND A WIND GUST OF 60 MPH...97 KM/H.

that's 830 miles diameter!!!! wow!!!
Member Since: April 23, 2011 Posts: 104 Comments: 14873
"AN
INTERESTING NOTE IS THAT THE DROPSONDE DATA INDICATES THAT THE
STRONGEST WINDS IN THE CONVECTION AT FLIGHT-LEVEL ARE SIGNIFICANTLY
LESS THAN THOSE NEAR THE SURFACE."
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Quoting Wiebel:


By uploading it to tinypic or imgur it doesnt use the bandwidth of the NHC / NOAA / thirdparty intel provider.

Bandwidth is limited. They might need it in case of emergency. No need to waste their bandwidth.
This, and a lot of times the image URL doesn't change but the image does - so someone linking something at 11pm could wind up seeing something at 5am that makes no sense to whatever they were saying.
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HURRICANE SANDY DISCUSSION NUMBER 19
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012
1100 PM EDT FRI OCT 26 2012

SANDY IS SHOWING CHARACTERISTICS OF A HYBRID CYCLONE THIS EVENING.
OVERALL...THE SYSTEM LOOKS LIKE A LARGE OCCLUDED FRONTAL LOW.
HOWEVER...SURFACE OBSERVATIONS DO NOT SHOW STRONG TEMPERATURE
GRADIENTS...AND CENTRAL CONVECTION IS OCCURRING IN BANDS TO THE
NORTHWEST OF THE CENTER. IN ADDITION...AMSU DATA FROM NEAR 2000
UTC INDICATED THAT THE SYSTEM STILL HAD A DEEP WARM CORE.
DROPSONDES AND SFMR DATA FROM A NOAA HURRICANE HUNTER AIRCRAFT
SHOWED A LARGE AREA OF 60 KT WINDS TO THE WEST AND NORTHWEST OF THE
CENTER...AND BASED ON THIS AND THE POSSIBILITY THAT STRONGER WINDS
WERE NOT SAMPLED...THE INITIAL INTENSITY REMAINS 65 KT. AN
INTERESTING NOTE IS THAT THE DROPSONDE DATA INDICATES THAT THE
STRONGEST WINDS IN THE CONVECTION AT FLIGHT-LEVEL ARE SIGNIFICANTLY
LESS THAN THOSE NEAR THE SURFACE.

THE CENTER HAS BEEN WOBBLING DURING THE EVENING...WITH THE INITIAL
MOTION A SOMEWHAT UNCERTAIN 010/6. THERE IS NO CHANGE TO THE TRACK
FORECAST REASONING FROM THE PREVIOUS ADVISORY. A DEEP-LAYER TROUGH
MOVING INTO THE EASTERN UNITED STATES SHOULD CAUSE SANDY TO TURN
NORTHEASTWARD WITH AN INCREASE IN FORWARD SPEED...AND THIS MOTION
SHOULD PERSIST FOR 48 HR OR SO. AFTER THAT...A NEGATIVELY-TILTED
SHORTWAVE TROUGH NEAR THE U.S. EAST COAST AND A RIDGE OVER EXTREME
EASTERN CANADA SHOULD CAUSE SANDY TO TURN TOWARD THE NORTHWEST AND
WEST-NORTHWEST...TOWARD AND OVER THE U.S. COAST. THE TRACK
GUIDANCE ENVELOPE SHIFTED A LITTLE TO THE EAST DURING THE FIRST 48
HR...AND THE FORECAST IS NUDGED IN THAT DIRECTION. HOWEVER...THERE
WAS LITTLE CHANGE AFTER THAT TIME...AND THE LANDFALL AREA AND TIME
IS CHANGED LITTLE FROM THAT OF THE PREVIOUS FORECAST.

SANDY IS CURRENTLY EXPERIENCING ABOUT 50 KT OF VERTICAL WIND SHEAR
WHICH IS DISRUPTING THE CONVECTIVE STRUCTURE. HOWEVER...VERY
STRONG UPPER-LEVEL DIVERGENCE ASSOCIATED WITH A TROUGH SOUTHWEST OF
THE HURRICANE IS LIKELY SUSTAINING THE CYCLONE. WHILE THESE
CONDITIONS ARE FORECAST TO CONTINUE...IT IS LIKELY THAT SANDY WILL
CONTINUE TO SLOWLY WEAKEN THROUGH 36 HR. SUBSEQUENTLY...THE
DYNAMICAL MODELS FORECAST THAT INTERACTION WITH THE U. S. SHORTWAVE
TROUGH WILL CAUSE SANDY TO RE-INTENSIFY PRIMARILY DUE TO
BAROCLININC ENERGY PROCESSES. THE INTENSITY FORECAST SHOWS SANDY
REGAINING HURRICANE STRENGTH IN 48-72 HR. HOWEVER...THE CYCLONE
WILL BE UNDERGOING EXTRATROPICAL TRANSITION AS THIS HAPPENS...AND
WHEN THIS PROCESS WILL BE COMPLETE IS UNCERTAIN. REGARDLESS OF THE
EXACT STRUCTURE AT LANDFALL...SANDY IS EXPECTED TO BE A LARGE AND
POWERFUL CYCLONE WITH SIGNIFICANT IMPACTS EXTENDING WELL AWAY FROM
THE LOCATION OF THE CENTER.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0300Z 27.7N 77.1W 65 KT 75 MPH
12H 27/1200Z 28.8N 76.7W 60 KT 70 MPH
24H 28/0000Z 30.4N 75.2W 55 KT 65 MPH
36H 28/1200Z 32.0N 73.3W 55 KT 65 MPH
48H 29/0000Z 33.8N 71.9W 65 KT 75 MPH
72H 30/0000Z 37.5N 72.0W 70 KT 80 MPH
96H 31/0000Z 40.0N 77.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 01/0000Z 42.0N 76.5W 35 KT 40 MPH...POST-TROP/EXTRATROP

$$
FORECASTER BEVEN
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Still a hurricane and still moving north at 7mph
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BULLETIN
HURRICANE SANDY ADVISORY NUMBER 19
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012
1100 PM EDT FRI OCT 26 2012

...SANDY REMAINS A HURRICANE AS IT MOVES SLOWLY NORTHWARD AWAY FROM
THE BAHAMAS...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.7N 77.1W
ABOUT 90 MI...145 KM N OF GREAT ABACO ISLAND
ABOUT 395 MI...630 KM SSE OF CHARLESTON SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...969 MB...28.61 INCHES
Member Since: Posts: Comments:
Quoting KoritheMan:


I know how to access this data, but I never understood why people constantly hide URLs. 70% of the stuff I click on is skillfully hidden behind tinypic or imgur. It's not as if the URLs in question will detract from the blog in any way, since they are posted in image form.

Kind of annoying tbh. >.>


What annoys me are those plastic slides on the salami packages that never close, and the tight twist seals on the arthritis pill bottles.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
BULLETIN
HURRICANE SANDY ADVISORY NUMBER 19
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012
1100 PM EDT FRI OCT 26 2012

...SANDY REMAINS A HURRICANE AS IT MOVES SLOWLY NORTHWARD AWAY FROM
THE BAHAMAS...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.7N 77.1W
ABOUT 90 MI...145 KM N OF GREAT ABACO ISLAND
ABOUT 395 MI...630 KM SSE OF CHARLESTON SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...969 MB...28.61 INCHES

Member Since: April 23, 2011 Posts: 104 Comments: 14873
Sandy remains a hurricane.
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Anyone heard from Baha today?
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Quoting trHUrrIXC5MMX:


any lower pressure than 970mb there...it's hard to read
968.
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I'll be there
Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting KoritheMan:


I know how to access this data, but I never understood why people constantly hide URLs. 70% of the stuff I click on is skillfully hidden behind tinypic or imgur. It's not as if the URLs in question will detract from the blog in any way, since they are posted in image form.

Kind of annoying tbh. >.>


By uploading it to tinypic or imgur it doesnt use the bandwidth of the NHC / NOAA / thirdparty intel provider.

Bandwidth is limited. They might need it in case of emergency. No need to waste their bandwidth.
Member Since: Posts: Comments:
Quoting Tropicsweatherpr:


It looks like it has turned according to the fixes by the NOAA plane.



I know how to access this data, but I never understood why people constantly hide URLs. 70% of the stuff I click on is skillfully hidden behind tinypic or imgur. It's not as if the URLs in question will detract from the blog in any way, since they are posted in image form.

Kind of annoying tbh. >.>
Member Since: Posts: Comments:
Quit quoting the troll and ignore him, please?
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Uh Oh*
I*
*run-on sentence.
*commas.
*period.

Just saying..

Anyways, it's not wise to quote him. This guy really has nothing better to do with his time, he's made loads of accounts to do one thing; troll us. It's sad, actually, such a waste of time to do for four years. Oh well.
Member Since: Posts: Comments:
Quoting THEYGOOFEDAGAIN:
a tropical storm watch means there is a possiblity of sustained winds 39mph and higher and a tropical storm warning means we are having winds 39mph or higher and we have been under a tropical storm warning ???sincce last night and nothing so far but thats happenes here every year the past 6 years we get nothing that they predict


Quoting CybrTeddy:
419.

Two words:

Grammar lessons.


??? wow. check that out


Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting Tropicsweatherpr:


It looks like it has turned according to the fixes by the NOAA plane.



any lower pressure than 970mb there...it's hard to read
Member Since: April 23, 2011 Posts: 104 Comments: 14873
419.

Two words:

Grammar lessons.
Member Since: Posts: Comments:
Quoting Chicklit:


Thank you Chicklit! I was looking back at earlier posts for some shear maps. Amazing they forecast her dropping to tropical storm, and then back into hurricane, with those ripping shears coming up. I know so much depends on joining the front, but still!
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Quoting THEYGOOFEDAGAIN:
wow we are still under a tropical storm warning here then? when is it gonna happen weve been waiting since last night and so far a trace of rain and 12mph wind in gusts


wait..sorry. This is the 18 A 8PM ADV..
Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting mitthbevnuruodo:


Ah lovely...so sad on my way home from work tonight...as is all windy and blowing all the changing colored leaves off the trees. Last week has been nothing but fog, so was hoping for a few 'ok' days before any strong winds came to blow them away...I swear it always happens though! So hard to enjoy autumn for long. Hope something left on the next nice'ish' day!


yeah you can tell by that crappy power poles on the pic... those trees may not handle hurricane winds standing...

I don't want to lose power but I can't afford a generator..maybe a bunch of candles could do it
Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting vegegrower:
Has Sandy made its NE turn yet?


It looks like it has turned according to the fixes by the NOAA plane.

Member Since: April 29, 2009 Posts: 75 Comments: 14892
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE TROPICAL STORM WARNING HAS BEEN DISCONTINUED FOR THE FLORIDA
COAST FROM JUPITER INLET SOUTHWARD TO DEERFIELD BEACH.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* FLORIDA EAST COAST FROM NORTH OF JUPITER INLET TO ST AUGUSTINE
* SOUTH SANTEE RIVER TO DUCK...INCLUDING PAMLICO
AND ALBEMARLE SOUNDS
* GREAT ABACO AND GRAND BAHAMA ISLANDS

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* SAVANNAH RIVER TO SOUTH SANTEE RIVER
* FLORIDA EAST COAST FROM NORTH OF ST AUGUSTINE TO FERNANDINA BEACH
* BERMUDA

IN ADDITION...GALE WATCHES ARE IN EFFECT FOR AREAS NORTH OF THE
TROPICAL STORM WARNING AREA. SEE STATEMENTS FROM LOCAL NATIONAL
WEATHER SERVICE FORECAST OFFICES.

INTERESTS ELSEWHERE ALONG THE EAST COAST OF THE UNITED STATES SHOULD
MONITOR THE PROGRESS OF SANDY.


When the DELMARVA pen could be under watches...how about the NYC/CT AREA?
Member Since: April 23, 2011 Posts: 104 Comments: 14873
LinkClick fronts SWLoop
night all.
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Quoting trHUrrIXC5MMX:
hi guys...
here is a pic of the road in and out for my house...look at the woodsy area..but I love this time for the fall colors



Ah lovely...so sad on my way home from work tonight...as is all windy and blowing all the changing colored leaves off the trees. Last week has been nothing but fog, so was hoping for a few 'ok' days before any strong winds came to blow them away...I swear it always happens though! So hard to enjoy autumn for long. Hope something left on the next nice'ish' day!
Member Since: Posts: Comments:
Quoting THEYGOOFEDAGAIN:
a tropical storm watch means there is a possiblity of sustained winds 39mph and higher and a tropical storm warning means we are having winds 39mph or higher and we have been under a tropical storm warning sincce last night and nothing so far but thats happenes here every year the past 6 years we get nothing that they predict</em>

Very disappointing, I'm sure.
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Has Sandy made its NE turn yet?
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Quoting Grothar:


It was from the Qing dynasty, but you were close.

Ah.
But the Ming made better Pottery.

:):))
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Quoting tropicfreak:
Post 398 Sandy claims its first troll....


Meh, is a recurring one with a different username LOL
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Sandy has quite the anticyclone.
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Quoting pottery:

Sounds like a Wise Old Saying, from the Ming Dynasty or something.

Grothar will know. He was there.....


It was from the Qing dynasty, but you were close.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting THEYGOOFEDAGAIN:
yes and we dint have anything here during this tropical storm warning

Anything from Isaac ?
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84 hours



120 hours

Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting THEYGOOFEDAGAIN:
our local news just said we are still under a tropical storm warning here until tommorow morning thats so funny still saying 30 to 45mph winds with gusts to 55mph and 3 to 5 inches of rain and since last night weve has a trace of rian and a high wind gust of 23mph lmao

You understand the difference between a Tropical Storm and an afternoon thunderstorm, right ?
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Quoting gordydunnot:
If the Pottery not broken don't fix it.

Sounds like a Wise Old Saying, from the Ming Dynasty or something.

Grothar will know. He was there.....
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we almost have the same death toll as Isaac...RIP to all of those
Member Since: April 23, 2011 Posts: 104 Comments: 14873
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Quoting THEYGOOFEDAGAIN:
i cant believe they closed the schoools here in florida today. it was sunny most of the day and just 20 minutes ago we had our first 3 or 4 drops of rain and a top wind of 23mph they dont even close our schools when we get 60 mph winds and 3 to 5 inches of rain everyday with out afternoon t storms all summer


I bet the kids are happy. ;)
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If the Pottery not broken don't fix it.
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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.

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