One more cut and paste from the
Washington Post Weather blog. I think they do a great job.
Current weather pattern is notorious for Mid-Atlantic hurricane landfallsThe future track of Hurricane Joaquin is uncertain and anxiously anticipated by coastal residents from North Carolina to New England. Steering winds high in the atmosphere will ultimately determine where Joaquin will track, and these winds are looking very similar to past cases of hurricane landfalls in the Mid-Atlantic.
Recent forecast models are mostly calling for a landfall along the Mid-Atlantic coast this weekend, with the notable exception of the European model. While it is tempting to dismiss the European as an outlier, it has historically been one of the most reliable models for hurricane tracks. In 2012, it nailed Hurricane Sandy’s northwest turn several days before other models predicted a similar track.
The question at this point is whether or not these models are correctly identifying and predicting the steering winds that Hurricane Joaquin will ride over the next few days. The ramifications of a track toward the East Coast — or away from it all-together — are critical for millions of Americans.
So what have past hurricanes done in similar situations?
...
Clockwise circulation around a high pressure ridge to the north and northeast of the hurricane will often mean a hurricane cannot curve eastward into the open Atlantic, since it would be going against the steering winds. Instead, this clockwise wind flow around the southern edge of high pressure grabs the hurricane and pushes it west.
Eric Webb, a student at North Carolina State University, created a graphic to illustrate the mid-level steering flow for 13 tropical storms that impacted the Mid-Atlantic since 1900. Strong high pressure over the Northeast — which is needed for such a track — is clearly evident.
There’s a very similar setup in the forecast later this week, when Hurricane Joaquin is expected to be approaching the East coast. This is almost a carbon copy of what has been historically observed during Mid-Atlantic hurricane landfalls. This strong high pressure area blocks the tropical cyclone from recurving out to sea and avoiding the Eastern Seaboard.
... click link to see graphics
