Sandy slams Cuba, intensifies over the Bahamas
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
Reader Comments
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I went in the ocean today with 2 other buddies bodysurfing the waves. There was no current because the bay protected the wind and the beach is not known to have rip currents.
Waves were running 7-10 feet, and the 10 footers were as time went by.
I'll keep you guys informed on when and if the winds start to intensify here.
sandy blasted. :o)
18Z GFS showing a lot closer approach to FL than the previous runs.
Nice, except I don't have gray hair.:)
P.S. Someone just looked over my shoulder and said some nasty words in German.
Hmmmm, watching the cam right now I hope you'll find something left from your lovely beach tomorrow ... Heavy blow is coming in.
Point Forecast: Jupiter FL
26.94°N 80.09°W
Last Update: 5:32 pm EDT Oct 25, 2012
Forecast Valid: 6pm EDT Oct 25,
Friday-Tropical storm conditions possible. Showers likely and possibly a thunderstorm. Mostly cloudy, with a temperature rising to near 84 by 9am, then falling to around 77 during the remainder of the day. North wind 31 to 36 mph, with gusts as high as 70 mph. Chance of precipitation is 60%.
Friday Night - Tropical storm conditions possible. A chance of showers and thunderstorms before 2am, then a slight chance of showers. Mostly cloudy, with a low around 72. Northwest wind 32 to 37 mph, with gusts as high as 65 mph. Chance of precipitation is 50%.
WHOAA, wonder why this went up so much for Jupiter?
NATIONAL WEATHER SERVICE SAN JUAN PR
525 PM AST THU OCT 25 2012
PRC001-013-017-027-039-054-055-059-065-073-075-08 1-091-093-101-107-
111-113-115-121-141-145-149-153-252215-
BARCELONETA PR-CIALES PR-FLORIDA PR-GUANICA PR-GUAYANILLA PR-
HATILLO PR-JAYUYA PR-JUANA DIAZ PR-LARES PR-MANATI PR-MARICAO PR-
MOROVIS PR-OROCOVIS PR-PENUELAS PR-PONCE PR-SABANA GRANDE PR-
UTUADO PR-VEGA BAJA PR-VILLALBA PR-YAUCO PR-ADJUNTAS PR-ARECIBO PR-
CAMUY PR-QUEBRADILLAS PR-
525 PM AST THU OCT 25 2012
AT 520 PM AST...DOPPLER WEATHER RADAR CONTINUED TO INDICATE A LINE
OF SHOWERS AND EMBEDDED STRONG THUNDERSTORMS MOVING STEADILY EAST
ACROSS PARTS OF WESTERN AND CENTRAL PUERTO RICO. THESE SHOWERS AND
STORMS WILL CONTINUE TO PRODUCE WIND GUSTS OF 35 TO 40 MPH...
FREQUENT LIGHTNING...BRIEF VERY HEAVY RAINFALL AND PONDING OF WATER
OR FLOODING IN LOW LYING AND URBAN AREAS AS THEY PROGRESS EASTWARD.
HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS AS THEY
MAY BE WASHED OUT. WATER LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO
RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY FLOOD WATERS.
INTENSE LIGHTNING IS REPORTED WITH THESE STORMS. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.
$$
BCS
To which I replied, "Sure. But stock up on supplies just in case. Power could go out. :) "
I'm overseas right now, and I won't be back until after whatever happens happens, but I've been following it enough to know that it's a potential history maker. You don't just get to "opt out" of that.
I might add that said friend lives just SW of Philly...
How are u guys faring? With the windfield expanding pretty much as predicted, most of North Andros could get the same kind of winds we get here in Nassau....
But, if someone is claiming a NW heading when it's really North, then isn't that inaccurate and worthy of correction, especially when combined with the other biases?
It is the heaviest so far. The wind is really coming in hard now.
Grothar - are you getting blown hard now?
Winds calmed down here for the moment.
Great... power just went out.... from one of those gusts, it seems. :o( Geez... and we are barely in the TS wind zone...
I have battery backup, but I want that to last as long as possible, so I'll get off now.
More later as Sandy progresses...
Mostly clear, with a low around 56. Windy, with a northwest wind 30 to 34 mph, with gusts as high as 45 mph.
We are OK heavy rain squall passing through right now and a little wind, some trees have been reported down earlier but so far we have kept electricity and phones although cable was out most of the day but is back now.
I expect the worst that we will get will happen later this evening/tonight unless there is a significant shift to the west over the next few hours.
[I better go find my flashlight.... lol]
what are your thoughts on our maximum winds from this storm?
We had a strong squall pass through GB about 30 minutes ago. It did not last long but it packed a good punch.
Monday Night
Clear. Low of 45F. Breezy. Winds from the NW at 15 to 20 mph.
And yea the model consensus is amazing. Likely overdone, but I have to wonder just how overdone it is with such a strong consensus.
IF the most recent NHC.Advisory position was correct, H.Sandy had been moving on the western side of CatIsland(CAT) -- overrunning the southwestern tip and the northern island -- and should now be cruising along east of Eleuthera(ELH,GHB,RSD)
The bottom line marks the 6hour path between the 2 most recent ATCF positions
The top line marks the 3hour path between the most recent ATCF position and the most recent NHC.Advisory position
Considering the hurricane's recent travel curvature, I wouldn't be surprised if the next ATCF position shows Sandy's path passing over easternmost Eleuthera.
http://www.ssd.noaa.gov/goes/east/carb/loop-vis.h tml
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