Henri Menaces New England After As Fred's Rains Leave

Tropical Storm Henri off the Southeast coast this morning
Strong upper level winds from the north are hindering
development but those winds are forecast to slacken
off and Henri is expected to become a hurricane
as it heads toward New England over the weekend.

What a strange, tropical time we're having in New England!

The remains of Tropical Storm Fred crossed southern Vermont and meandered toward Maine overnight. 

And now, Tropical Storm Henri is creating an even bigger threat to the region. While all that is going on, the region's weather and weather patterns are typical of Florida, not New England.  

I'll do a quick Fred recap before getting into the real, very important news, which is Henri. 

Fred's remains unleashed almost all of its havoc on southern New England.  A patch of intense rains created serious flash flooding from Hartford to Worcester and on into the Boston area. Four cars were completely submerged beneath an underpass in Worcester and four people had to be rescued.

This heavy rain is not good, soaking the ground before Henri's torrential rains get there. Henri could cause one helluva flood in southern New England. 

This complex of storms rotated, with three confirmed tornado touchdowns in New Jersey, at least one possible touchdown in southern New York, maybe one in Connecticut. Tornado warnings flew in the Boston suburbs too.

Here in Vermont, Fred in my view was perfect. Torrential storms failed to materialize in soggy southern Vermont, so there were no reports of significant issues there, despite flash flood watches that had been in effect. 

Fred's rains stubbornly hung on in far northern Vermont, which actually still needs the precipitation (As of Thursday, before the rains hit, the three Vermont counties closest to the Canadian border were still in moderate drought.  

Burlington received a respectable 0.9 inches of rain from Ex-Fred.  My unofficial rain gauge in St. Alban collected 0.75 inch.  The soaking rains Thursday probably put another dent in the drought, so that's good. But trouble looms south of us. Here's the real news:

HENRI MENACES

What a weird situation Tropical Storm Henri is!  It's lurking off the East Coast, and was about 330 miles southeast of Cape Hatteras, North Carolina with top winds of about 65 mph early this morning. 

That's not at all an odd place for a tropical storm or hurricane to be this time of year, but Henri's future behavior is anything but typical. 

On those rare occasions when a hurricane menaces New England, the storm is on it's typical recurvature process near the end of its life cycle. 

In the Atlantic, troughs of low pressure often pick up a hurricane and make it move north, then northeast up to the North Atlantic to die. Most of the time, this process makes a hurricane miss the East Coast as they move north out into the open waters.

Sometimes, these hurricanes move right up the East Coast, with damaging, sometimes historic, disastrous effects. When they do this, they are moving at a fast forward speed, with a predictable path toward the Northeast.

Henri is different.

There is that trough of low pressure in the East that will pick Henri up and move it northward. That part is pretty normal. But a ridge of high pressure in eastern Canada is building.  That will nudge Henri westward and it will move due north or even northwest toward New England instead of out to sea.

On top of that, that Canadian ridge will slow Henri down near New England, which is opposite of what normally happens.   

Just some of the forecasts tracks for Henri. As you can
see, there's a lot of questions on where it comes
ashore in or near New England Sunday.

This makes forecasting this thing even more of a nightmare and more of a high stakes game than you can imagine for meteorologists. 

After all, dangerous storm surges, high winds and flooding rains are all in play for southern New England and Long Island with this thing. You want to get the forecast right, as lives depend on it. 

Exactly where the worst of it hits is a real question for sure. 

Upper level winds have so far kept Henri from strengthening enough for to become a hurricane. Those upper level winds will relax today as Henri roams over the toasty Gulf Stream, so it will strengthen.

Forecasting the future strength of tropical systems is very tricky.  If it strengthens a lot, it will of course be a more powerful storm when it gets to New England. If Henri sputters, it will still be a problem by the time it gets here, but it will be somewhat of a more manageable problem.

Here's another tricky part: The waters closer to New England are too cold to sustain a hurricane's strength.  So it will probably start to weaken as it approaches the coast.  If its forward motion is slower than normal, which is likely, it will have more time to weaken over water.

BUT, the ocean water south of New England is warmer than normal, which could slow the weakening a bit. And if Henri gets really strong enough, which seems kinda likely, it will be the first hurricane to make landfall in New England since Hurricane Bob in 1991. (Devastating Irene was a tropical storm by the time in reached New England in 2011).

The next question is where will Henri land?

For the record, there is currently a hurricane watch in effect in Long Island, New York and along the southern New England coast through Connecticut, Rhode Island and Massachusetts south of Boston including Cape Cod. Of course, Martha's Vineyard, Nantucket and Block Island are also under that hurricane watch.

Anything at or just east of landfall will get hurricane force winds and worse, a nasty storm surge. Which will be made nastier by astronomically high tides due to a full moon.  Areas just west of Henri will get dangerous, flooding rains. (That's what happened to Vermont with Irene in 2011 - we were just west of its track and got the heaviest rains).

Complicating things further, Henri is forecast to take a sharp right turn beneath that Canadian ridge once the storm gets to New England.  How far inland will Henri be before the sharp right turn hits?  That has implications for what effects we here in northern New England get

VERMONT IMPACTS

The short answer to the question, how will Henri affect Vermont is, "Who knows?" But we can start taking stabs at this answer.

Northern areas at this point don't appear to have much to worry about.  If that right turn happens as expected, the further north in Vermont you go, the more likely you are to be a bystander to Henri.  

There are a few models that bring Henri close enough to affect virtually all of Vermont.  It should also be noted that Henri's "cone of uncertainty" from the National Hurricane Center includes virtually all of Vermont.  Anything within that "cone of uncertainty" includes places where meteorologist think a tropical system might go, given forecast errors.

All that means that the risk from Henri is lower in northern Vermont than places further south, but still real. People in northern Vermont should keep an eye on forecasts, because you never know if a tropical system does something weird and unexpected. 

Henri is weird enough to begin with, after all.  

For southern Vermont, the best case scenario would be for Henri to come ashore in far eastern New England, then immediately take that sharp right turn. If that were to happen, the storm would be no biggie for folks in far southern Vermont. 

Worst case scenario is if Henri came ashore much further west, say in western Long Island, and more worrisomely delayed its sharp right turn a bit, southern Vermont would be in play for some very heavy rain and possibly serious flooding.  Strong winds would be an issue in some spots in the southern tip of Vermont, too.

Then there are a bunch of in between scenarios.  Anyone in southern Vermont should be prepared for some impacts from Henri to be on the safe side.  

Any impacts of Henri in Vermont, if they do occur would be mostly on Sunday and Sunday night.  Expect forecasts to shift with Henri here in Vermont and the Northeast in general as its unpredictable path becomes better understood by meteorologists as the storm approaches.

Here's what to do today regarding Henri:

-- If you're planning a trip to the New England coast this weekend, cancel it. 

-- If you're already vacationing there, leave today. No use messing with a storm like that and you'll just be more people, in addition to the locals that might end up needing help. The fewer people around down there, the better.

--- If you live in southern Vermont, sit tight but listen for forecast updates on Henri.  If you live in a flood prone area, have a plan on what to do if there's a flood or flood warning

-- If you live in central or northern Vermont, carry on with what you were doing, but listen for forecast updates in case Henri ends up having effects on that part of the state after all. 

Before the storm hits, expect typical Florida weather in Vermont today and Saturday. Anyone who steps outside will know right away it's damn tropical out there. Lingering fog and drizzle should lift this morning into partly cloudy skies.  Chances for showers are quite low, but a few might pop up in the humid air. 

On Saturday, there will be a few more afternoon showers and thunderstorms. They will still be hit and miss, but more numerous than today. 

Here's another odd twist. As we know, summer thunderstorms generally go west to east in Vermont. In Florida in the summer, they usually go east to west, coming ashore on the Atlantic side of the peninsula. Tomorrow, in Vermont, any showers and storms that do get going will probably move generally east to west, just like Florida.