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Sandy slowly turning extra-tropical; Historical storm possible

By: wxchaser97 , 6:44 AM GMT on October 27, 2012

Hurricane Sandy
Sandy's satellite appearance has degraded throughout the day. High wind shear has exposed the center of circulation and has tilted the storm. The maximum sustained winds have decreased due to the loss of convection over the center. Nevertheless, Sandy still has a closed vigorous circulation and is fully warm core so she remains a hurricane. Currently Sandy has 75mph winds, a 969mb pressure, and she is moving NNE at 7mph. Aircraft recon is investigating Sandy to determine her strength. Sandy could be a historic storm and she needs to be taken seriously.

Structure of Sandy
As stated above, wind shear in impacting Sandy in negative ways. UW-CIMSS shear map shows a ULL and trough shearing Sandy from the south and the west. Water vapor imagery shows dry air on the south side of the circulation. Cooler SST values and lower TCHP values aren't giving Sandy as much fuel for strengthening as earlier. These factors have lead to the winds decreasing and the southern side of Sandy to be without deep thunderstorms. In short, Sandy is weakening right now and is slowly turning extra-tropical. All is not bad with Sandy though, she is still a minimal hurricane. Convection may be trying to recover the center but that has to be watched in case it is blown away again. Aircraft recon has found that winds are still around 70-75mph and that the circulation is closed. They have also found that Sandy remains a fully warm core storm. As long as Sandy keeps a warm core and a closed vigorous circulation she will remain a tropical storm or hurricane. There is light at the end of the tunnel for Sandy over the next few days. Sandy will be getting over the gulf stream which should allow some strengthening. Also she should be able to mix out some dry air which would allow thunderstorms to move over the center. I think Sandy should weaken to a tropical storm due to poor conditions and not so good organization right now. However, I think Sandy can regain hurricane strength before turning post-tropical. Her wind field will be increasing even more as she heads off toward the NE. She already has an impressive wind field and the extra-tropical process will make it bigger. Strong winds will continue to be felt over a big area. Sandy will be entering a baroclinic zone over the next few days from a trough over the US. This baroclinic energy will be the final straw for Sandy's tropical life. Sandy won't be tropical over cold shelf waters and being feed by non-tropical energy near the US coast. Tropical or not, Sandy will still have the same impacts(see impact section for more details). We need to continue to monitor the structure of Sandy to see if any changes occur.

Models and track
Models have come into great agreement that Sandy will hit the East Coast. They suggest a landfall near NYC to NJ to Delmarva area. The timing of landfall is predicted to be in about 4 days or so. Strength could range from a cat2 equivalent storm to a moderate to strong TS equivalent storm. They predict major impacts would arise from Sandy and her post-tropical self. A sub 950mb storm is possible to make landfall if the models are right. To get Sandy to the Mid Atlantic/ NE she has some work to do. Right now she is off to the east of FL and just to the north of the Bahamas. Sandy is currently in a weaker steering environment and she is slowly moving to the north-northeast. Sandy will begin to respond to a trough over the eastern US. This trough is strong and has lots of energy with it. The tilt and timing of this trough will have a big impact on the final destination. If the trough comes in later and is tilted more positive Sandy would be taken more out to sea. This is an unlikely scenario and basically no models forecast this. With a stronger and more negative tilted trough Sandy would go NE and then turn to the NW. Sandy would phase into the trough and move along with the flow, to the NW. Models support this situation and this is the likely track. Sandy should mostly avoid the SE and hit southern New England. While models aren't perfect people in Sandy's path need to be preparing for potential major impacts.

My forecast
I am forecasting Sand to weaken to a tropical storm today. She will bottom out with 65-70mph winds before conditions improve. I think Sandy will be able to restrengthen into a hurricane over the gulf stream. A secondary peak of 80mph is likely in about 3 days. Sand should make landfall with 70-75mph winds. Her winds would slowly decrease as she heads inland. I think Sandy will turn to the NE today and slowly begin to speed up. Sandy should then continue to the NE until reaching 34-37N and then turn to the NW. I have Sandy making landfall in central NJ in several days. Sandy should then get turned to the north and exit into Canada. This is a pretty high confidence forecast due to model support.

Tropical storm and hurricane warnings are still in affect in the Bahamas and Florida. These areas have been getting squally weather and high waves. These conditions are expected to continue for about another day. There has been some damage in some areas but they are lucky it isn't as strong as before. Sandy has already claimed at least 41 lives in the Caribbean and this number is expected to rise. As Sandy heads NE North Carolina and South Carolina should get some impacts. Off shore measurements say TS force winds aren't too far from the coast and the should be able to move inland as Sandy gets closer. She will also bring rain and rough surf to these areas and a tropical storm warning is in effect. Once Sandy gets to the Mid Atlantic and NE her impacts are really felt. It is here where Sandy will be remembered and when she could become a historic storm. High winds, heavy rain, flooding, and waves/surge will be felt. Storm surge will be pushed into New York and surrounding areas. Such a large wind field will generate a bigger storm surge, this was shown earlier by Hurricane Isaac. Rain in excess of 10 inches is possible in many areas. Flooding will be likely in areas that usually get flooded. The rain will combine with some leaves on the trees to weaken the trees. Strong winds will have an easier time to uproot trees in the NE. Power lines will be taken out, small objects will be blown around, and some minor structural damage is possible. Tropical storm watches and warnings will be required over the next couple days. Not just the coastal areas will receive impacts from Sandy. Inland areas could get some rain, wind, and even snow. Higher elevations could get a couple feet of snow while other areas a couple inches. Millions upon millions of people will be affected by Sandy over the next week. You need to take this very seriously and listen to officials. This is no hype, Sandy could be a historic hurricane/nor'easter. If you are not prepared you could potentially die. As long as you are ready and listen to officials/warnings you should be fine. Once again, please stay safe if you are in Sandy's path.

Have a great night/morning everyone and I will have a new update today or tomorrow.
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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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3. WunderAlertBot (Admin)
12:30 PM GMT on October 29, 2012
wxchaser97 has created a new entry.
2. wxchaser97
12:04 PM GMT on October 27, 2012
Quoting KoritheMan:
Good blog.

Thanks Kori.
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1. KoritheMan
7:45 AM GMT on October 27, 2012
Good blog.
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I'm a CMU Honors student and love meteorology and extreme weather. I've been fascinated by weather since I was 5, and plan on becoming a meteorologist

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