My apologies for not posting more on Hurricane Bill. Time has been limited for me lately (and, unfortunately, will continue to be so). As such, since Bill looked like a minimal threat, I was foregoing the updates. Some guidance does hint at a threat for eastern New England, though. So, I don't want to completely ignore Bill. So, below the fold I've got a brief (well, not THAT brief, but for me it is) update on Hurricane Bill...
The bottom line, before I delve into any details, is that Hurricane Bill should stay free and clear of most land. The biggest threat is to the Canadian Maritimes, but at which time Bill should at least be weaker, if not entirely non-tropical. And, depending on how hard Bill's right turn is, even the Maritimes may miss Bill. Bermuda should escape the brunt, as Bill sneaks by to the west; the Lesser Antilles should escape the brunt, as Bill sneaks by to the north; and New England should escape the brunt, as Bill sneaks by to the east.
Here's the official National Hurricane Center forecast track for Bill:
...you can see that eastern New England is in the possible track swath. However, they are on extreme western edge of the swath - indicating a very low probability of landfall. Note that the Maritimes are much more under the gun, but that Bill could also cut east of them.
Let's hope he does miss land, as here's what he's looking like right now:
...very impressive. Bill is up to a Category 4, 115kt hurricane. If this hit anyone head-on at this intensity it would be disastrous, especially since Bill is also extremely large. Thankfully, this simply will not occur. Even if Bill does manage to make landfall in the Canadian Maritimes, he will be significantly weakened, as wind shear increases ahead of the cold front he'll be riding, and as he begins running across cooler waters. Here, in fact, is the wind forecast from various models (courtesy of Alan Huffman's great web site!):
...Bill's impact on the Maritimes would be around 120hrs (or 108hrs in the unlikely event that the storm managed to hit Cape Cod). The official NHC forecast (OFCL) on the above plot looks excellent, as they're going right down the middle of the traditionally best guidance you see on that plot (GFDL, GFDT, GFDN and HWRF). At 120hrs that drops Bill down to about a Category 1 hurricane (Cat 2 by 108hrs).
The real question I think a lot of folks want to know (though my perception may be biased given where I and many of my friends are from) is: What are the chances this hits New England? Well, here's what the various models show:
...the only one west far enough to show landfall on New England is the NOGAPS (the Navy's model). It does not have a great track record and tends to have a westward bias. That said, it was the first model to shift Katrina's track west to New Orleans. Also, most of the other models have a poleward (north and east) bias. So, the NOGAPS can't entirely be ruled out. However, I do think it is fair to say that it is probably too far west. Another way to examine this is to look at the spread in the GFS Ensemble members (GFS Ensemble is the American weather model rerun with multiple "perturbations" to produce various possible outcomes):
...you can see that very few members bring Bill to or very close to New England. So, at this point, a New England landfall cannot be ruled out. But, it looks very unlikely. Many times NHC (correctly) downplays the actual landfall location, since effects are felt far and wide. But with a storm accelerating northward the impacts on the western side (where north winds around the circulation center are offset somewhat by the surrounding air flow out of the south) are reduced; also, north winds are offshore for most locations (except in the north side of Cape Cod). So, an actual landfall in New England is dramatically more significant than a mere "close pass". As such, determining if there will be landfall in New England is important and, at this point, that looks unlikely. There is just enough of a remaining chance that New Englanders should continue monitoring Hurricane Bill. But, at this point, a significant impact is not be expected. The Canadian Maritimes are a different story. I see no reason to vary at all from NHC's official forecast... so, the Maritimes (esp Nova Scotia) stand about a 50/50 shot at direct landfall... though it will be from a rapidly weakening, Category 1, Hurricane Bill.
One point, I'm downplaying significant impacts, but swells and waves will cause significant rip currents throughout the U.S. and Canadian East Coasts. Over the years many swimmers and surfers have been killed by these rip currents. They should not be taken lightly. Extreme caution should be taken by beachgoers insisting on venturing into the water this week.