Very Brief Sandy Update

At moment Hurricane Sandy is doing what’s expected. The storm is tearing through the Bahamas. It has weakened.

It doesn’t look like it did last night when an eye and some banding were visible. Visiting Cuba will do that to you!

The Hurricane Center has joined the chorus explaining Sandy won’t be like other hurricanes at landfall.

REGARDLESS OF THE EXACT TRACK OF SANDY…IT IS LIKELY THAT SIGNIFICANT IMPACTS WILL BE FELT OVER PORTIONS OF THE U.S. EAST COAST THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.

That includes us here in Connecticut.

NHC has another problem. Sandy will sure transition or be transitioning from a warm to cold core storm. That will broaden its wind field. Unlike a ‘pure’ hurricane, Sandy’s top winds won’t be right at the eyewall.

NOTE THAT THE TROPICAL CYCLONE WIND SPEED PROBABILITIES ARE NOT DESIGNED TO HANDLE THE TYPE OF STRUCTURAL CHANGES ANTICIPATED WITH SANDY DURING THE FORECAST PERIOD. AS A RESULT…THESE PROBABILITIES WILL UNDERESTIMATE THE ACTUAL RISK OF STRONG WINDS AWAY FROM THE CENTER OF SANDY.

I’ll try and write a little about the 00z GFS before bed tonight. I’m hoping for more agreement with the ECMWF, meaning a more (hopefully) reliable forecast and farther away from us!

Sandy: Not Good News

The latest run of the GFS has started to come around toward the European’s solution for Hurricane Sandy. They’re still far apart–not as far. And now the GFS puts Connecticut in the bullseye!

We’re close enough and there’s now enough agreement to assume this threat is real for us in Southern New England.

Can the storm still miss us? Sure, though that’s less likely now. It would be foolish to plan based on that assumption.

The GFS is particularly nasty bringing the storm south of Long Island then turning it east where it slows it to a crawl before heading north. We will have a sustained period of strong winds, possibly tropical storm force and certainly tropical storm or even hurricane force gusts.

There will also be a sustained period pre-storm where the wind will have an easterly component. As with Irene, these winds will have the effect of driving water into Long Island Sound, raising the water level even before storm induced waves are added. Coastal flooding is likely.

To make matters worse, all of this is happening near the full moon when tides are normally higher (and lower) than normal.

No two storms are alike. Even with comparable winds we will certainly find damage in some places that escaped Irene while some areas battered in 2011 will be spared.

The first impacts will be felt Sunday, but mostly as a nasty day–overcast, chilly, breezy and some brief showers. By Monday the wind picks up as does the rain. The strongest wind and rain hit on Tuesday.

Hurricane Sandy, probably not a hurricane at landfall, has the potential to be worse than Irene!

The trees have already lost a lot of leaves, which will stand in our favor. There’s not much else ‘good’ I can tell you.

Now is the time to begin your preparations. What can you use before it spoils? What didn’t you have for Irene or the Halloween snowstorm of 2011?

It’s still difficult to be totally specific and I assume some of what I write today will be proven wrong.

I usually try not to scare you about weather. Today I will. It is warranted.

Be smart. Be prepared. Start now.

Sandy: She’s A Super Freak

There are easy forecasts and difficult ones. Hurricane Sandy is surely the latter!

Wednesday at 11:00 PM the National Hurricane Center said Sandy was 90 mph. Thursday morning at 12:30 AM, only 90 minutes later, that was changed.

RECENT REPORTS FROM AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INDICATE HURRICANE SANDY HAS RAPIDLY STRENGTHENED…AND MAXIMUM SUSTAINED WINDS ARE NOW ESTIMATED TO BE 110 MPH

That’s not a small change! And this rapid intensification happened while the northern flank of the storm was interacting with Cuba and it’s rough terrain.

The BBC reported 70% of Jamaica without power. Now Sandy is crossing Cuba before heading toward the Bahamas.

A storm doesn’t need to be very powerful to do damage if it hits the East Coast. A strike from the Atlantic looks likely.

What’s much more up-in-the-air is where?

The 00z GFS came in again with a Canadian Maritimes landfall Wednesday afternoon. The 00z ECMWF, the European, brings Sandy to the coast near the mouth of Delaware Bay Monday afternoon, then takes it into Washington.

Someone’s gotta be wrong!

Either of those scenarios would diminish damage to Connecticut, though we’d still get battered. Of course Connecticut is the midpoint between the two proposed paths.

So, again we’re stuck knowing a little, but not enough.

An East Coast landfall looks likely. That part’s easy.

Both models have been moderately consistent for the last 24 hours or so. Something is fooling one of them… or both. Hopefully Thursday will reveal the truth.

We’re Still Not Sure Where Sandy’s Going

We’re at the point in storm tracking where I begin to get frustrated. I want to give a specific forecast. I cannot.

Well, I could, but it would be bulls**t. At this moment no one knows exactly where Hurricane Sandy will go!

Over the years researchers have developed dozens of computer models to try and predict storms through the laws of physics. Most only see a few days into the future. With Hurricane Sandy so far away, both in time and distance, the most used models are the ECMWF produced by the European Centre for Medium-Range Weather Forecasts and the GFS from the Weather Service.

Since each model uses its own shortcuts to allow computers to crunch the data each often has its own solution. That’s the case with Hurricane Sandy. As we get closer we hope the models come into alignment.

As of Wednesday evening the ECMWF was calling for landfall in South Jersey late Monday while the GFS brings Sandy to the Canadian Maritimes a few days later! That’s leading forecasters to believe this storm will affect the East Coast.

We’re still days away from knowing exactly where.

Sandy And Her Two Model Friends

I just took a look at the European (ECMWF) and GFS models. They’re our best predictors for medium range weather. Both are now predicting an East Coast strike for Hurricane Sandy. Obviously that is not good news.

The GFS brings landfall to Maine while the Euro hits New Jersey just south of New York City.

Let’s get real for a moment. Both of these models have varied greatly over the last few days. They have changed trajectories by hundreds of miles. There’s a big difference between striking Cape Cod and Asbury Park as the European model has suggested over the last day.

I am more concerned than I was yesterday. Both of today’s scenarios would affect Connecticut and, of course, we’re the compromise position between the two.

It’s still too early to go nuts, but it is the time to start thinking about what you wish you’d had on hand during Irene.

Do you use rechargeable batteries? Are they charged?

Do you have food in your freezer you’d like to start using now?

Are your prescriptions up-to-date?

New England is nothing more than a potential target for Hurricane Sandy. It is still too early to think its post-weekend location can be accurately forecast.

As we get closer we’ll know more.

I’ve Got Sandy On My Mind

Here’s my problem with Sandy. I can look at all the computer runs and sense something’s wrong. Too many things are happening I’ve never seen before. You’d think in nearly 30 years here I’d seen it all.

I spoke to Bob Hart on my way home. He’s a professor at FSU. No one knows more about tropical weather. His mind is very attuned to math and physics which eliminates some of the interim steps folks like me have to take.

He was born to be a teacher. We’re lucky.

Bob said there were some storms in the 1800s that produced what is Sandy’s worst case scenario.

There’s a reason stuff like this happens infrequently. A huge number of conditions must come into alignment. If one or two aren’t as forecast it all goes to hell! With Sandy this far away in time and distance there’s no parameter that’s not suspect.

Neither Bob nor I want to believe Sandy could strike Connecticut.

We talked about the weaknesses of models.

Well, he talked. I listened.

Tropical systems are really small compared to the weather we most often see. The computer models are often too coarse to understand the complexity of these tightly wound storms that mathematically can fall between the cracks.

Sometimes tropical storms induce feedback loops. That’s a condition that overwhelms the model’s algorithms and allows the condition to grow out of control. It makes the model output suspect at best and poisoned so much it has to be discarded at worst.

To those who think meteorologists love big storms. No.

I’ll be busy for the next week.

Sandy: No Panic, But Some Concern

It’s much too early to get worried about Tropical Storm Sandy. Unfortunately, at the same time, we can’t find a reason to dismiss it as a potential threat to Connecticut!

Early Tuesday evening Sandy is around 225 miles SSW of Kingston, Jamaica. Yesterday the storm was stationary. This evening it’s moving north at 8 mph.

We know Sandy is better organized! What was just a cluster of thunderstorms now has the curved bands you’d expect with a tropical system.

Sandy is also over very warm water. Think of that oceanic heat content as gasoline thrown on a smoldering fire.

Sandy is forecast to hit Jamaica Wednesday with hurricane force winds. From there it will continue toward Cuba. Both Jamaica and Cuba have mountainous interiors. That will likely slow the storm’s development

From there the official track stays east of Florida cutting through the mainly flat Bahamas.

What you’ve just read is what we think is likely. Now we come to the part of the forecast that’s much less certain… carved in cottage cheese, if you will.

In order to pin down the forecast we look at a variety of computer models. These take the storm’s characteristics, turn them into mathematical variables, then apply the laws of physics.

Each computer model uses a slightly different method to ‘solve’ the forecasting problem. We have many models because none of them is consistently right! Each has strengths and weaknesses.

One model, produced by the European Centre for Medium-Range Weather Forecasts, showed great skill last hurricane season, especially with Hurricane Irene. Its solution for Sandy is scary for Connecticut.

The ECMWF curves Sandy on a counterclockwise path through the Atlantic, hitting Long Island and cutting through Connecticut from southeast to northwest. It is an exceptionally rare path for a storm. It would have a devastating impact on our state.

A storm like this could easily rival the damage from Irene… but wait.

The ECMWF prediction is for early next week. That’s still a long way away, both in distance and time. Small errors in a computer model early on multiply with time.

At this time there’s just no way to dismiss the ECMWF’s forecast. That’s not to say it will come true, it’s just one of many possible scenarios. There’s little individuals can do and not much you should do today.

Hopefully, as we go forward the computer models will begin to agree and we’ll be able to tell you to relax or get ready.

Oh Sandy

I was working on my story, speaking with a video editor, when Rachael called across the newsroom.

“The 12Z’s in.”

She was referring to the European model. In these early stages of Tropical Storm Sandy the European has been the most consistent in bringing the storm to New England. The 12Z run is reasonably similar to early output.

The European is still out of line with nearly everything else we use, but it can’t be discounted.

There’s still no certainty or even likelihood Sandy’s coming here. There’s just no way to dismiss the possibility.

We’ll try and treat the storm with the respect it deserves without unduly alarming people. We’re still a long way from it’s possible arrival time early next week.

Stay tuned.

Sandy’s Now Official

People think meteorologists hype the weather. Not so. Well, at least not so where I can see.

Sandy is now officially a tropical storm. It’s 375 miles SSW of Kingston, Jamaica. Top winds are 45 mph.

It’s not moving! The slower the storm the more difficult to forecast.

The most likely scenario shows Sandy starting to move sometime Tuesday. By Wednesday she’ll be over Jamaica, then Eastern Cuba.

After that the picture is a little more blurry.

The technical discussion talks about Sandy the way a parent might gush over a newborn. All the conditions are right for growth.

A CENTRAL DENSE OVERCAST FEATURE APPEARS TO BE FORMING. IN ADDITION…INNER-CORE CONVECTIVE BANDING HAS DEVELOPED SOUTH AND NORTH OF THE CENTER… WITH OUTER BANDING FEATURES ALSO DEVELOPING OVER MUCH OF THE EASTERN SEMICIRCLE. UPPER-LEVEL OUTFLOW HAS EXPANDED AND IMPROVED IN ALL QUADRANTS…ESPECIALLY TO THE NORTHWEST WHERE IT HAD BEEN RESTRICTED BY AN UPPER-LEVEL TROUGH.

The spaghetti plots at the top of this entry hint at the most likely scenario, the storm goes out to sea!

The ECMWF aka, the “European” is the outlier, bringing Sandy up the East Coast, making landfall near the Hamptons on Long Island then heading northwest toward Monticello, NY.

That path would slice right through Connecticut!

The ECMWF is alone coming to this conclusion When so many models have a totally different solution the tendency is to assume the ECMWF has not yet properly modeled our current scenario. The problem is you can’t dismiss the European because it’s been so good in the past.

THE MODELS BEGIN TO DIVERGE SIGNIFICANTLY WITH THE NORMALLY RELIABLE ECMWF TAKING SANDY NORTH-NORTHWESTWARD CLOSER TO THE U.S. SOUTHEAST COAST…WHEREAS THE GFS…HWRF…GFDL…AND OTHER LESS RELIABLE MODELS TAKE THE CYCLONE NORTH-NORTHEASTWARD. GIVEN THE HISTORICAL RELIABILITY OF THE ECMWF MODEL…THE OFFICIAL FORECAST TRACK REMAINS SIMILAR TO THE PREVIOUS ADVISORY TRACK

What yesterday looked like a Wednesday arrival now looks more like next Tuesday morning.

Seriously, this is too far away for worry. The models aren’t yet locked in. We’re still a week out.

It’s going to take a lot more certainty before I start getting nervous.

It deserves close scrutiny.

It’s Almost Sandy Time

The GFS solution is strange. It looked like the classic setup for the Fujiwhara effect where “Sandy” would orbit an offshore low. That would push the storm into the coast! Bad.

Instead the GFS combines three lows to produce a vigorous system, but not a hurricane and a good chance the worst wind would be away from us.

A lot of folks want to know about Sandy. There’s no Sandy yet. There is a cluster of clouds in the warm water south of Jamaica.

Both the European and GFS models build this storm and bring it up the East Coast. First effects for us would be after dark, Saturday night.

I am not putting water in my tub. We are not stocking up on canned goods.

The global models aren’t built to handle tropical systems like this. Even small errors over this much time can produce a totally different outcome. There will be forecast errors.

The GFS solution is strange. It looked like the classic setup for the Fujiwhara effect where “Sandy” would orbit an offshore low. That would push the storm into the coast! Bad.

Instead the GFS combines three lows to produce a vigorous system, but not a hurricane and a good chance the worst wind would be away from us.

There are four GFS runs every day. Each one will be somewhat different than the last.

Right now there’s nothing to do but watch.