Hurricane Sandy liveblog: Which way is Sandy headed? The latest 'Frankenstorm' track

A Frankenstorm? The National Hurricane Center computer models are forecasting a track that shows Hurricane Sandy heading toward Delaware.

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Friday Oct. 26 3:45 p.m.

The latest European hurricane forecasting model (ECMWF) shows the predicted track of hurricane Sandy coming into closer agreement with the US Global Forecast System (GFS).

The ECMWF model was showing a more southern track for Sandy, with landfall occurring on Monday afternoon. Now, the European model shows Sandy on a more northward track with the center of the storm coming ashore at New Jersey early Tuesday morning.

If you look at the 2 p.m. EDT Friday National Hurricane Center's forecast track for Sandy, the European supercomputers predict Sandy will land at the northern part of the cone (see below).

Bear in mind that meteorologists stress that, beyond 24 hours, the accuracy of these models becomes less certain. And this is one of the more complex storm systems, with many moving parts, which could alter Sandy's track. For example, if the blocking high pressure area in the northern Atlantic moves off sooner than predicted, Sandy wouldn't hang a left toward the East Coast. But most forecasts predict the high to force Sandy to turn toward the coast.

Friday Oct. 26 3:35 p.m.

Hurricane Sandy, which according to the AP has so far left 39 people dead in the Caribbean, is shaping up to be a big deal. The Monitor's Ron Scherer quotes forecasters warning of widespread flooding, storm surges, snow in the Appalachians, and heavy wind damage from the slow-moving storm.

Weather Underground's Jeff Masters says that the storm is "likely to be a billion-dollar disaster." At AccuWeather, meteorologist Joe Lundberg writes that if Sandy makes landfall near Long Island or northern New Jersey, which he says is the most likely scenario, it would be "an economic and human disaster on multiple levels."

Another meteorologist described Sandy in even more colorful terms: A blog post by AccuWeather's Senior Vice President Mike Smith quotes a Facebook post from a "very prominent and respected National Weather Service meteorologist," which reads: "I've never seen anything like this and I'm at a loss for expletives to describe what this storm could do."

Both Virginia and Maryland  have declared states of emergency ahead of the storm, and voluntary evacuation orders have been issued for New Jersey's Cape May County, the Garden State's southernmost county.  

There are a lot of moving parts to this weather system, meaning that the computer models could be inaccurate and Sandy could fizzle. But if you live on the East Coast between Virginia and Maine, it's worth it to stock up on batteries and water, and to make a straightforward evacuation plan. Check the Monitor's list of hurricane preparedness tips for specifics.

Friday Oct. 26 1:55 p.m.

Sandy is just a Category 1 hurricane (74-95 mph winds). What's all the fuss?

The short answer: Storm surge over a wide area, over a sustained period.

Aside from the hybrid mega-storm aka Frankenstorm stuff that we've cited below, there's the sheer size of Sandy. She's big. Sandy's got some girth, and she's expected to get bigger.

Sandy has grown in size every day, with tropical storm force winds now extending 275 miles  from the center. But Monday or Tuesday, there are forecasts that indicate Sandy could have strong winds 400 miles from her center.

The 11 a.m. EDT National Hurricane Center report showed some slowing of her speed, and her winds aren't getting stronger. And Sandy's a little less "organized." But her reach is growing. Rather than high winds in tight, her 80 mph winds are reaching out further. That's part of the concern among meteorologists.

High winds will keep the storm surge threat high. "This large wind field will likely drive a storm surge of 3 - 6 feet on Monday and Tuesday to the right of where the center makes landfall, on the mid-Atlantic or New York coasts. These storm surge heights will be among the highest ever recorded along the affected coasts, and will have the potential to cause hundreds of millions of dollars in damage," writes  Dr. Jeff Masters at Weather Underground.com

Dr. Masters goes on to write:

"The latest H*Wind analysis from NOAA's Hurricane Research Division put the destructive potential of Sandy's winds at 2.1 on a scale of 0 to 6, and the destructive potential of the storm surge much higher, at 4.2 on a scale of 0 to 6. The full moon is on Monday, which means astronomical tides will be at their peak for the month, increasing potential storm surge flooding. With Sandy's strongest winds expected to last at least 12 hours near the time of landfall, the peak storm surge will affect the coast for at least one high tide cycle, and possibly two. This will greatly increase the potential for storm surge damage and coastal erosion. If Sandy hits Long Island, as the GFS (Global Forcast System) model predicts, the storm surge will be capable of over-topping the flood walls in Manhattan and flooding portions of the New York City subway system."

Friday Oct. 26 12:55 p.m.

Gov. Martin O'Malley is declaring a state of emergency across Maryland as Hurricane Sandy approaches, the Associated Press reports.

O'Malley said Friday the declaration gives the state flexibility to activate the Maryland National Guard and provide assistance to local emergency managers. He says everyone should prepare for extreme weather by reviewing their family emergency plans, checking their emergency supplies staying informed.

Heavy rain and high winds are expected to reach the Maryland coast Saturday night. Forecasters predict several days of foul weather including the possibility of snow in the western Maryland mountains.

Friday Oct. 26 12:40 p.m.

Why is Sandy a 'Frankenstorm'? There's more to the moniker than a hurricane arriving just ahead of Halloween.

Hurricane Sandy is a tropical cyclone. But computer models say it's on a collision course with a "extratropical trough" - a low-pressure storm system associated with the jet stream.

A tropical cyclone gets its energy from warm water. So, under normal circumstances, Hurricane Sandy would lose energy as it moved north and came ashore on the East Coast.

But the computer models say that won't happen this time. In this rare case, Sandy will meet up with an "extratropical trough" which draws energy not from the surface temperatures but from the temperature differential between the cold polar air and warm tropical air. The jet stream itself "is tightly coupled to that temperature contrast. The contrast in temperatures between air masses is ultimately what drives the jet stream, and the stronger the temperature contrast, the stronger the jet stream will be," explains Adam Sobel an atmospheric scientist and a professor at Columbia University.

The jet stream, which this extratropical trough is associated with, is unusually far south right now.

When Sandy moves ashore it will likely form a hybrid storm with properties of both types of storms - thus the 'Frankenstom' label. This type of storm is rare and the computer models are struggling to figure out exactly what will happen. But as Sobel notes in a thorough explanation of this on Climatecentral.org, "this new energy source will enable Sandy to maintain its intensity, or maybe even increase it."

Friday Oct. 26 11 a.m.

Meteorologists are looking at the computer models and are freaking out. They've not seen predictions of barometric pressures dropping this low in these parts of the US in their lifetimes.The NOAA Hydrometeorological Prediction Center Extended Forecast discussion notes that computer models "SHOW PRESSURE SOLUTIONS WELL BEYOND WHAT HAS EVER BEEN OBSERVED NEAR THE NEW JERSEY/NEW YORK COAST (EVEN EXCEEDING THE 1938 LONG ISLAND EXPRESS HURRICANE)."

As the Capital Weather Gang blog observes:

"The clash of the cold blast from the continental U.S. and the massive surge of warm, moist air from Hurricane Sandy will cause the storm to explode and the pressure to crash.

These historic low pressure levels simulated by the model are equivalent to a category 3 or 4 hurricane, which have peak winds over 115 mph. But Sandy’s winds will not be that high, because as it transitions into this hybrid hurricane-nor’easter monster, its core will unwind. So its peak winds will diminish, but strong winds will be felt over a vast area."

Friday Oct. 26 10:10 am

Remember Snoctober? Last October, just before Halloween, an early snowstorm hit the East Coast and knocked out power to more than 2 million residents from Pennsylvania to New England. Many homes were without power for days and some folks didn't get their electricity back for weeks. 

Well, state governments and private utility companies don't want a repeat of the Snomaggedon of last fall. Utility companies from North Carolina to Vermont are canceling vacations and arranging for power repair crews to come from the Midwest to help out.

AP reports: "A spokesman for Unitil in New Hampshire says the utility is talking to crews as far away as Tennessee and Michigan to make sure they will be available. Alec O' Meara said typically, Unitil talks about reaching to contractors as far as three days in advance of a storm, but the calls are being made sooner than that this time."

The Associated Press reports that Vermont is also warning farmers to prep for Sandy.

"The Vermont Agency of Agriculture is advising farmers to harvest crops still in the fields. For those who need power for milking cows or cooling milk tanks, the agency warns to prepare for power outages by making sure generators are working."

Friday Oct. 26 9 a.m.

Check out Miami-based CBS TV weather forecaster David Bernard's forecast for Sandy on video. He offers a good explanation of why Sandy's northward track will be blocked by a large high pressure area in the Atlantic, pushing it westward toward Delaware. Then, Sandy is likely to encounter a cold front, as the jet stream dips deep into the US South. That collision will could produce 1 to 2 feet of snow in the higher elevations of West Virginia and Pennsylvania.

Friday Oct. 26 8:45 a.m.

Where is Sandy headed? It's still too early to say definitively. Here's what the computer model shows which was issued by the National Hurricane Center at 8 a.m. Friday. This track shows Sandy taking a hard left turn toward the East Coast on Monday. It has the eye of the storm hitting Delaware Tuesday at 2 a.m. and heading inland toward Pennsylvania and the Ohio valley.

Hurricane Sandy tears through Bahamas, weakens to Cat. 1

Friday Oct. 26 8 a.m.

Hurricane Sandy passed through the Bahamas early Friday knocking out power but there were no reported deaths. The Associated Press reports a total of 22 fatalities across the Caribbean in Sandy's wake.

"Generally people are realizing it is serious," said Caroline Turnquest, head of the Red Cross in the Bahamas, who said 20 shelters were opened on the main island of New Providence.

Sandy hit the Bahamas as a Category 2 Hurricane, with winds above 105 m.p.h. but weakened to a Category 1 hurricane Thursday night, with sustained winds of 80 m.p.h. Currently forecasters expect Sandy to remain a Cat. 1 hurricane or weaken to a tropical storm as it moves northward.

But meteorologists are warning that it's not just the strength of Sandy that's the issue. National Oceanic and Atmospheric Administration forecaster Jim Cisco has warned that  a confluence of weather systems could produce what he has dubbed a "Frankenstorm," arriving along the East Coast of the US with tropical storm-force winds Tuesday. Cisco said that there was a 90 percent chance that most of the U.S. East Coast would get steady gale-force winds, flooding, heavy rain and maybe snow starting Sunday and stretching past Wednesday.

“This storm is dangerous,” says Bryan Norcross, a hurricane specialist at the Weather Channel told The Christian Science Monitor. “If it comes to pass like the consensus forecast, it will be unprecedented, we have never seen anything that looks like this.”

Thursday, Oct. 25 5 p.m. EDT

After battering eastern Cuba, Hurricane Sandy intensify as it crosses the Bahamas today, with its western edge grazing Florida's coast.  The US National Weather Service warns that Sandy might "help spawn a sprawling storm that could bring significant rain, wind and waves to the Northeast." 

Sandy's exact track is hard to pin down, but meteorologists warn that that it is unlikely to head out to sea, thanks to a storm to its east and an area of high pressure west of Greenland, which together are helping to confine Sandy to the East Coast.

What's more, as Weather Underground notes, Sandy is expected to collide with an eastward-moving dip in the jet stream, creating the potential for a "hybrid" storm with high winds spread over a large area.

At this point, Sandy is expected to make landfall on Monday, somewhere between Virginia and Maine.

To make matters even worse for East Coasters, the storm's land Monday is a full moon, meaning a high tide, which increases the chances of significant coastal flooding.  

Snowfall is also a concern particularly in the Appalachians. As New Englanders learned last Halloween, heavy snowfall combined with leafy trees has a tendency to knock down power lines.