Hurricane Sandy hits Jamaica, dumps heavy rains on Haiti

By: Dr. Jeff Masters , 8:54 PM GMT on October 24, 2012

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Hurricane Sandy hit the southeastern tip of Jamaica near 3:20 pm EDT this afternoon, as a Category 1 hurricane with 80 mph winds and a 973 mb pressure. According to NOAA's Historical Hurricane Tracks website, Sandy is the thirteenth hurricane to make a direct hit on the island, and the first since Hurricane Gilbert of 1988. Kingston, Jamaica recorded sustained winds of 44 mph and a pressure of 972 mb in the west eyewall of Sandy at 4 pm EDT. The eastern tip of Jamaica will see the strongest winds of the right-front quadrant and the heaviest damage, though. A distorted eye is apparent on visible satellite loops, but Sandy is showing only minor disruption to its inner core structure as a result of hitting Jamaica. According to the Jamaica Observer, "Alligator Pond [in St Elizabeth] was inundated with the high waves that came ashore. We are now getting reports of impacts out in St. Catherine, Portland and St. Thomas as the ground becomes saturated. We are now seeing where light poles are toppling and landslides being reported and roadway being flooded to the point where there is impeded access in east St. Thomas." Heavy rains from Sandy are falling in Haiti. A NOAA forecast based on microwave satellite data predicts 12 inches of rain for the tip of Haiti's southwestern Peninsula, which will likely cause life-threatening flash flooding. Fortunately, much lighter rainfall amounts are predicted for the capital of Port-au-Prince, where 350,000 people still live in the open under tarps in the wake of the January 2010 earthquake. In August, flooding from Hurricane Isaac killed at least 29 people in Haiti.


Figure 1. Hurricane Sandy over Jamaica. The large 55-mile diameter eye hit the island at 3:20 pm EDT, and crossed over the eastern tip of the island. The eye has been distorted into an odd triangular shape, due to interaction with the land area of Jamaica.


Figure 2. Predicted 24-hour rain amounts from Hurricane Sandy for the period ending at 8 am EDT Thursday, October 25, 2012. The prediction is based on microwave satellite data of precipitation. Image credit: NOAA/NESDIS.

Near-term forecast for Sandy
Sandy doesn't have much time over water before it makes landfall on the southeastern coast of Cuba near 10 pm EDT this Wednesday night, and the strongest the storm is likely to be then is a 90 mph Category 1. Passage over the rugged terrain of Cuba should weaken Sandy's winds by 20 - 30 mph, and will likely destroy the hurricane's eyewall. It will be difficult for the storm to rebuild its eyewall and regain all of that lost strength, in the face of the high wind shear of 20 - 30 knots it will encounter Thursday and Friday. However, the loss of the eyewall will cause Sandy's radius of tropical storm-force winds to expand, spreading out the winds over a wider area of ocean, and increasing the storm surge threat. This large wind field will likely drive a storm surge of 5 - 8 feet in the Bahamas, which is more characteristic of a storm with winds 20 mph higher. I expect that Sandy will be a 65 - 70 mph tropical storm as it traverses the Bahamas, and the storm will make its closest pass by Nassau around 10 pm EDT Thursday.


Figure 3. This Maximum Water Depth storm surge image for the Bahamas shows the worst-case inundation scenarios for a Category 1 hurricane with 85 mph winds, as predicted using dozens of runs of NOAA's SLOSH model. For example, if you are inland at an elevation of ten feet above mean sea level, and the combined storm surge and tide (the "storm tide") is fifteen feet at your location, the water depth image will show five feet of inundation. No single storm will be able to cause the level of flooding depicted in this image. Sandy's maximum storm surge may reach levels portrayed in this image for some islands in the Bahamas. See wunderground's storm surge pages for more storm surge info.

Sandy: a potential billion-dollar storm for the mid-Atlantic, New England, and Canada
The latest set of 12Z (8 am EDT) model runs are in, and they portray an increased risk to the U.S. and Canadian East Coasts for early next week. The GFS model, which had been showing that Sandy would head to the northeast out to sea, now has changed its tune, and predicts that Sandy will double back and hit Maine on Tuesday evening. The ECMWF model, which has been very consistent in its handling of Sandy, now has the storm hitting Delaware on Monday afternoon. These models are predicting that Sandy will get caught up by the trough approaching the Eastern U.S., which will inject a large amount of energy into the storm, converting it to a powerful subtropical storm with a central pressure below 960 mb and sustained winds of 60 - 70 mph. Winds of this strength would likely cause massive power outages, as trees still in leaf take out power lines. Also of great concern are Sandy's rains. Given that ocean temperatures along the Northeast U.S. coast are about 5°F above average, there will be an unusually large amount of water vapor available to make heavy rain. If the trough of low pressure approaching the East Coast taps into the large reservoir of cold air over Canada and pulls down a significant amount of Arctic air, as predicted, the potential exists for the unusually moist air from Sandy to collide with this cold air from Canada and unleash the heaviest October rains ever recorded in the Northeast U.S. Another huge concern is storm surge flooding. Sandy is expected to have tropical storm-force winds that extend out more than 300 miles from the center, which will drive a much larger storm surge than its winds would ordinarily suggest. The full moon is on Monday, which means astronomical tides will be at their peak for the month, increasing potential storm surge flooding.

There remains a lot of model uncertainty on where Sandy might go, and I still give a 30% chance that the storm will have a minimal impact on the U.S. An extra set of balloon-borne radiosondes is going to be launched at 2 pm EDT on Thursday all across the U.S., which should help tomorrow evening's model runs make better forecasts of where Sandy might go. Extra radiosondes will be launched every 6 hours through Saturday afternoon.

Jeff Masters

Hurr Sandy staring down (Jewelsblues)
Looking onto Caribbean Sea, from Santo Domingo, Dominican Republic
Hurr Sandy staring down

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18z GFS run is similar to 6z. It sends Sandy out to sea and develops something else in the NE:

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Quoting kmanislander:
Sandy will likely step it up a notch tonight before landfall in Cuba. A short transit over Eastern Jamaica coupled with very high TCHP below will allow the hurricane to strengthen very quickly IMO



Agreed, to me it's not a question of strengthening, it's a question of are we talking RI or Explosive Deepening...?
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18Z GFS EXTENDED 24 OCT hr 153 TILL XXX



LARGE ERRORS APPLY
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Quoting AllStar17:


Hopefully this is the solution it makes it mind up with.

Well we can hope all we want, but it's looking less and less likely. I'd put the odds of it recurving at 20%.
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NAEFS model at 144 hours..geez NYC if this proves true..wow
Member Since: August 6, 2011 Posts: 4 Comments: 41829
Raw Sat Estimates sit at 6.4...
Let's just say Sandy is at least a Category 2. I could see her getting to Minimal Category 3 status before reaching Cuba.
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Sandy will likely step it up a notch tonight before landfall in Cuba. A short transit over Eastern Jamaica coupled with very high TCHP below will allow the hurricane to strengthen very quickly IMO

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Quoting wxchaser97:
Silly GFS, make up your mind already. Choose US/Canada hit or out to sea, please don't flip flop.

18Z 138hrs:


12z 138hrs:


Nearly 5 degrees east on the new model run.
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If it comes close to the mouth of the Chesapeake, tidal flooding will be really bad, especially with a full moon on Sunday.
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I am definitely leaving the out to sea scenario wide open. I stuck with the GFS for the past few days and I still see it as a real possibility that she doesn't have any NE impacts.

Focusing on the present, which is more important right now, I will boldly predict recon finds a high end Cat 2 upon arrival and a Cat 3 upon leaving:



Reminds me so much of the West Pac storms we've watched bomb out this year with the raw T # shooting way up. This is a rapidly intensifying storm. I didn't think it could do it with all that land but it's doing it.
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18Z GFS INIT 24 OCT hr 144 TILL 144

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yep NAEFS model at 114 hours going in somewhere between wash dc and NYC...............
Member Since: August 6, 2011 Posts: 4 Comments: 41829
Quoting TropicalAnalystwx13:
18z GFS is back out to sea...dang it, make up your mind.


Hopefully this is the solution it makes it mind up with.
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18Z GFS INIT 24 OCT hr 138 TILL 144

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Silly GFS, make up your mind already. Choose US/Canada hit or out to sea, please don't flip flop.

18Z 138hrs:


12z 138hrs:
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I like the triangular eye.
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Interesting, the GFS has switched back to it's original idea of going out to sea. This helps Sar2401 with his forecast. Gotta give it to the guy, he sticks with one forecast, even if many models disagree.
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NAEFS model has sandy starting to go in somewhere..hmmm near wash dc?102 hours....................
Member Since: August 6, 2011 Posts: 4 Comments: 41829



It looks like Sandy will cross right over Cuba's highest peak (pico turquino, 6400 ft) much like it crossed over Jamaica's highest peak (blue mountains, 7400 ft). There is more land to traverse in Cuba though. Interesting to see how she comes out on the otherside.

As hurricane sandy threatens to make landfall on eastern Cuba with heavy rains and strong winds, the Provincial Defense Council in the province of Holguin began the evacuation of citizens in areas under flooding risk.
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Just re-read this blog post. 350k living out in tents and tarps in Haiti, still. That's something to reality check on. Makes a few days without power small in comparison.
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Quoting Hurricanes305:


Looks like its moving NNW if that continues it could miss a large part of the Cuban Mountains. I dont understand the fact that it strengthens back into a hurricane.


Sandy's eye entered Jamaica at 3:20 p.m. and is now in the process of exiting. At the most, three hours over land.
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18Z GFS INIT 24 OCT hr 129 TILL 144

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Quoting CaicosRetiredSailor:


Boy that North central coast of Jamaica is getting a pounding!
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Quoting JeffMasters:


Latest GFS phase space forecast shows Sandy still subtropical in the Gulf of Maine.



Jeff Masters

This would mean the NHC would be issuing advisories on Sandy still as she hit the Northeast, I presume?
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Quoting reedzone:
Looks like the GFS is going out to sea... again. However, this is the 18Z. 00Z will be a bit more reliable.


18z GFS still goes out to sea but didn't shift further east...in fact Sandy looks to make a closer approach to NC before making the turn.
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18z GFS is back out to sea...dang it, make up your mind.
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First ADT after coming off of Jamaca and it shows a cat 4 in the Raw category


UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 24 OCT 2012 Time : 211500 UTC
Lat : 18:21:02 N Lon : 76:35:27 W


CI# /Pressure/ Vmax
4.4 / 975.8mb/ 74.6kt


Final T# Adj T# Raw T#
4.4 4.4 6.4

Estimated radius of max. wind based on IR :N/A km

Center Temp : -41.9C Cloud Region Temp : -74.0C

Scene Type : EYE

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : MW AdjEnd
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 90km
- Environmental MSLP : 1007mb

Satellite Viewing Angle : 21.6 degrees
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Quoting TropicalAnalystwx13:
This is not the appearance of a Category 1 hurricane. Based on satellite appearance alone, Sandy is probably a Category 2. And an intensifying one at that.

no question... Really nice looking storm now. By far the best looking one in the carribean this year.
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18Z GFS INIT 24 OCT hr 120 TILL 144

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At the rate things are going there is a decent chance Sandy will make it to major hurricane status before making landfall. How the mountains affect Sandy will be huge.
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Quoting TomballTXPride:

Cody ~ is the current thinking that Sandy will be subtropical or extra-tropical by the time she reaches New England, if she makes landfall there? And will she go from tropical to sub-tropical then to extra-tropical in that order.

Thanks in advance!

It may be post-tropical by the time it reaches New England, but it's equally likely it remains a subtropical storm. And yes, it will probably turn subtropical before becoming extratropical, if it does.
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Thanks Doc. Going to be a nervous weekend. Florida isn't out of it yet either. I doubt we'll see any wind or rain here in SC.
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Member Since: August 6, 2011 Posts: 4 Comments: 41829
Guys not to get too far of topic here, but 7 years ago today Hurricane Wilma was making landfall in S. FL:



Sandy looks ready to go RI, she probably has a good 10-12 hours over water. Things could be interesting tonight...
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Quoting CybrTeddy:
Reminds me of Paloma when she was about to bomb out back in 2008.

This is not a 80mph cat1 anymore, more like a cat2.
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Quoting BrickellBreeze:
Looks like a slight wobble east and then back West.



Looks like its moving NNW if that continues it could miss a large part of the Cuban Mountains. I dont understand the fact that it strengthens back into a hurricane.
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This is not the appearance of a Category 1 hurricane. Based on satellite appearance alone, Sandy is probably a Category 2. And an intensifying one at that.

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18Z GFS INIT 24 OCT hr 111 TILL 144

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Just more info
NAM at 51 hours
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Quoting gulfshoresAL:

I believe Pico Real de Tourquino is the highest mountain in Cuba. 6,578 feet.


Yep! - He must have been thinking one island over (Hispaniola - Pico Duarte)?
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Big squall BahaHurican was talking about earlier

Member Since: July 18, 2010 Posts: 50 Comments: 1909
Looks like the GFS is going out to sea... again. However, this is the 18Z. 00Z will be a bit more reliable.
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18Z GFS INIT 24 OCT hr 102 TILL 144

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Quoting BrickellBreeze:


Alot of heat to work with.
What you posted was old. Needs to be updated.
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Quoting Maryland1:
Ash Wednesday storm. One more time. With the spring tide, you couldn't make a more ugly scenario for the East Coast. Let's start hoping for a very big turn, because the alternatives on the models aren't real promising.
local met just said, from washington dc up to maine is in the danger area for sandy coming ashore, folks please pay attention to YOUR local warnings ok, looks like from Monday on..could be an historic low, one for the record books if it proves true..power outages maybe for days, just one of the dangers since most of the trees still have their leaves up there..and then there is coastal and stream flooding etc..well you get the picture..this will be a strong storm, and huge in area as storms go he said...you have a few days ahead warning..prepare and wait it out
Member Since: August 6, 2011 Posts: 4 Comments: 41829

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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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