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Sandy slams Cuba, intensifies over the Bahamas

By: Dr. Jeff Masters , 2:39 PM GMT on October 25, 2012

Hurricane Sandy shrugged off wind shear of 20 knots and passage over the southeastern tip of Jamaica yesterday afternoon, explosively deepening into a top-end Category 2 hurricane with 110 mph winds. Sandy made landfall in Southeastern Cuba around 1 am EDT this morning near Santiago de Cuba, which experienced sustained winds of 78 mph, gusting to 114 mph. Winds at Guantanamo Bay, Cuba peaked at 58 mph, gusting to 72 mph, at 3 am local time this morning, and the base received 3.51" of rain from Sandy as of 8 am EDT this morning. Punta Lucrecia, Cuba on the north coast of Cuba received 8.42" of rain from Sandy as of 8 am EDT. Cuban state media is reporting that one person was killed on Cuba, and damage was heavy, with thousands of homes damaged or destroyed. Damage was also substantial on Jamaica, where one person was killed, and power was knocked out for 70% of the island's residents. One death has been reported in Haiti due to flooding.

Sandy survived the crossing of Cuba's high mountains with its inner core relatively intact, and is now re-intensifying over the warm waters of the Central Bahama Islands. The latest 9:30 am center fix from the Hurricane Hunters found a central pressure of 965 mb, down 3 mb in 1.5 hours. The eye is intermittently visible on satellite loops, and Sandy appears to be holding its own against the high 30 knots of wind shear affecting it.


Figure 1. Hurricane Sandy approaching landfall in Southeast Cuba as seen by Cuban radar at 10:15 pm EDT Wednesday, October 24, 2012. Image credit: Cuban Institute of Meteorology.


Figure 2. Morning satellite image of Sandy.

Forecast for Sandy
Wind shear is expected to rise to 40 - 55 knots by Friday, as Sandy interacts with a trough of low pressure to its west. The high shear should disrupt Sandy's inner core and reduce the maximum winds. However, the trough will also inject energy into Sandy, and the hurricane's winds will spread out over a wider area of ocean, keeping the storm surge threat high. This large wind field will likely drive a storm surge of 5 - 8 feet in the Bahamas. Sandy will make its closest pass by Nassau around 8 am EDT Friday.

The latest set of 00Z (8 pm EDT) and 06Z (2 am EDT) computer model runs are in substantial agreement for the next 3 days, but Sandy's future is as clear as mud after that. Sandy will continue to punish the Bahamas today and Friday, as it tracks north to north-northwest. Sandy will probably come close enough to the Southeast U.S. on Saturday afternoon to spread heavy rains to the coasts of South Carolina and North Carolina. However, the 4 - 6 day computer model forecasts for Sunday - Tuesday diverge widely. The GFS model, which has been one of our two top models for predicting hurricane tracks the past two years, has been very inconsistent with its handling of Sandy. Runs of the GFS model done 6 hours apart, at 8 pm last night and 2 am EDT this morning, were 300 miles apart in their position for Sandy on Tuesday, with the latest run predicting a landfall in Maine on Wednesday morning. On the other hand, the ECMWF model, our other top model for predicting hurricane tracks, has been very consistent in its handling of Sandy. The ECMWF model has Sandy hitting Delaware on Monday afternoon, the same forecast it has had for three consecutive runs. The other models tend to follow one extreme or the other, and NHC is picking a solution somewhere in the middle of these two extremes. An extra set of balloon-borne radiosondes is going to be launched at 2 pm EDT Thursday all across the U.S., which should help this evening's model runs. Extra radiosondes will be launched every 6 hours through Saturday afternoon.


Figure 3. This Maximum Water Depth storm surge image for the Bahamas shows the worst-case inundation scenarios for a Category 2 hurricane with 105 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.

The Northeast U.S. scenario
If Sandy makes landfall farther to the north near Maine and Nova Scotia, heavy rains will be the main threat, since the cold waters will weaken the storm significantly before landfall. The trees have fewer leaves farther to the north, which will reduce the amount of tree damage and power failures compared to a more southerly track. However, 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, 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., Nova Scotia, and New Brunswick. This Northeast U.S. scenario would probably cause damages near $100 million dollars.

The mid-Atlantic U.S. scenario
Landfall Monday along the mid-Atlantic coast on Monday, as predicted by the ECMWF and NOGAPS models, would likely be a billion-dollar disaster. In this scenario, Sandy would be able to bring sustained winds near hurricane force over a wide stretch of heavily populated coast, causing massive power outages, as trees still in leaf fall and take out power lines. 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. Fresh water flooding from heavy rains would also be a huge concern. Given the ECMWF's consistent handling of Sandy, I believe this mid-Atlantic scenario has a higher probability of occurring than the Northeast U.S. scenario. However, it is likely that the models are overdoing the strength of Sandy at landfall. The models have trouble handling the transition from tropical storm to extratropical storm in these type of situations, and I expect that the 940 mb central pressure of Sandy predicted at landfall Monday in Delaware by the ECMWF model is substantially overdone.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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ULL forming to her west over western Cuba

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Quoting LargoFl:
model tracks aside..we have a powerful hurricane out there and we need to watch it carefully til it clears florida and heads northward...NHC says its going to grow in size, so one model says 150 miles out, another says 100 miles out..IF the storm is 240 miles wide..the models dont matter..we get the rains, and gusts..whats the hangup?..its there and we watch it..period....i need a break lol..see ya all later


If its 240 miles wide, then wouldn't the radius be 120 miles on either side. Also, from the NHC...

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 30 MILES...45 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140
MILES...220 KM.
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Quoting jambev:

Good morning from (almost) sunny Jamaica. The reports of extensive damage are overstated. In Kingston, we have downed trees and tree limbs together with some power lines. In fact, 70% of customers are without power but given a cat 1 storm this is not surprising. The infrastructure particularly in the rural eastern parts will be damaged and will be costly, as usual, to repair. However, I drove to my office in downtown Kingston and saw little evidence of any serious impacts.
Good news. I,ll take it.:)
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Quoting MiamiCane2012:
Why no mention of the encroaching Florida effects, eh, Masters? You've totally skipped out on Florida as far as this system would go.

Can't say I'm fond of that, at all!

At any rate, G'rmoning, everyone!
I think the warnings issued yesterday say it all. She will remain off coast and Eastern FL will receive Trop Storm conditions for about 24hrs. I personally think we will be surprised more by wind rather than rain. But thats just my opin.
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Quoting JRRP:
I think Sandy is 22.9n 75.1w
NHC see it 22.4n 75.5w
Link

With the size of Sandy, a few .?degrees is not going to matter.
.
.
.
.
I'm out
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Quoting AussieStorm:
Good night all, stay safe. I'll be back in the morning.
Cheers
AussieStorm
Good night Aussie.
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Quoting JRRP:
I think Sandy is 22.9n 75.1w
NHC see it 22.4n 75.5w
Link


Appears to have jogged a little to the left.
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Good morning from (almost) sunny Jamaica. The reports of extensive damage are overstated. In Kingston, we have downed trees and tree limbs together with some power lines. In fact, 70% of customers are without power but given a cat 1 storm this is not surprising. The infrastructure particularly in the rural eastern parts will be damaged and will be costly, as usual, to repair. However, I drove to my office in downtown Kingston and saw little evidence of any serious impacts.
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Convection burst will probably put Sandy at a minimal cat-3 soon.
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Good night all, stay safe. I'll be back in the morning.
Cheers
AussieStorm
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86. JRRP
I think Sandy is 22.9n 75.1w
NHC see it 22.4n 75.5w
Link
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Sandy cut across from the eastern to the western side of guidance.

So basically Dr Masters is saying, strong, but not Euro strong, which would probably mean less snow.
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model tracks aside..we have a powerful hurricane out there and we need to watch it carefully til it clears florida and heads northward...NHC says its going to grow in size, so one model says 150 miles out, another says 100 miles out..IF the storm is 240 miles wide..the models dont matter..we get the rains, and gusts..whats the hangup?..its there and we watch it..period....i need a break lol..see ya all later
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80. 7544
now be agood time for someone to post a steering map that shows the high above sandy building in like the nam is trying to show anyone tia looks like andros is land is going to get a good lashing as shes building new convection on the west side at this hour that could expand westward
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According to historical storms near where Sandy is, she is destined to make history with her track
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78. JRRP
now... sandy will move more North or NNW than NNE
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Quoting nrtiwlnvragn:


Standard for JFV

Ah, I see. I'm slow on the uptake this morning. :)
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Quoting RickWPB:
Two models I try not to pay attention to are the NAM and the NOGAPS.

NAM = Not Always Meaningful
NOGAPS = NO Good At Predicting Storms

:^)


Thanks for the laugh! That's awesome.
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Quoting KBgetoutthegrill:
Historically, how accurate has the NAM model been. NAM showing that NW turn towards FL now.

The NAM has been one of the poorest performing models over the years.
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Quoting sar2401:

You can't say you're fond of the idea that south Florida appears to have dodged a bullet on this one? You'd like to see Miami crushed, or what?


Standard for JFV
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71. JRRP
Quoting unknowncomic:
I would say the NAM is an outlier. Could it be correct?
.
yes
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I guess this is the front/trough that's going to clash with Sandy.


Link
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69. JRRP
NAM the best ??? LOL

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whew, this should wake people up in the northeast if they arent aware yet...................................look at that..a hurricane all the way up to virginia
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Quoting MiamiCane2012:
Why no mention of the encroaching Florida effects, eh, Masters? You've totally skipped out on Florida as far as this system would go.

Can't say I'm fond of that, at all!

At any rate, G'rmoning, everyone!

You can't say you're fond of the idea that south Florida appears to have dodged a bullet on this one? You'd like to see Miami crushed, or what?
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Historically, how accurate has the NAM model been. NAM showing that NW turn towards FL now.
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64. 7544
so now the closest to se fl will be at 8am friday rather at 2 am sandy expected to slow down some
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Quoting unknowncomic:
I would say the NAM is an outlier. Could it be correct?
we will find out tomorrow, if its right we get a stormy rainy day.probably will anyway
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Quoting JRRP:
I would say the NAM is an outlier. Could it be correct?
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storms havent made it to the west coast yet.......
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58. JRRP
Quoting originalLT:
Can't see the NAM being correct, as far as Florida goes, the storm would have to turn NW right now for that to happen, and it's not, It is basically moving North, with even an East based component to it-- as of right now.

yes!!!! that is exactly my point
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Quoting originalLT:
Can't see the NAM being correct, as far as Florida goes, the storm would have to turn NW right now for that to happen, and it's not, It is basically moving North, with even an East based component to it-- as of right now.
that nam might be saying rainfall with that green shading
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Quoting LargoFl:
FrankenStorm wow..thats going to catch on i bet up there


It started already......LOL
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Two models I try not to pay attention to are the NAM and the NOGAPS.

NAM = Not Always Meaningful
NOGAPS = NO Good At Predicting Storms

:^)
Member Since: December 31, 1969 Posts: Comments:
Quoting RitaEvac:
Punta Lucrecia, Cuba recorded sustained winds of 96mph with gust to 118mph overnight.

She's churning the Atlantic waters with vengeance and all that power and energy is headed for the east coast. Once the energy is in motion there is no stopping it, remember what the water does, it hits, floods and destroys everything in it's path.
ive never been in a wind thats gusting 118 mph..must be awful
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Can't see the NAM being correct, as far as Florida goes, the storm would have to turn NW right now for that to happen, and it's not, It is basically moving North, with even an East based component to it-- as of right now.
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SANDY is going to be going NW or NNW Soon now!
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Punta Lucrecia, Cuba recorded sustained winds of 96mph with gust to 118mph overnight.

She's churning the Atlantic waters with vengeance and all that power and energy is headed for the east coast. Once the energy is in motion there is no stopping it, remember what the water does, it hits, floods and destroys everything in it's path.
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FrankenStorm wow..thats going to catch on i bet up there
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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather

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