From the 5PM update at the NHC
"Late in the period the track model spread remains considerable, as
the global models continue to have issues depicting the synoptic-
scale pattern over the eastern United States and western Atlantic in
4-5 days. The evolution of the mid/upper-level low currently
centered over the Ohio
Valley and how it interacts with the western
Atlantic subtropical ridge appear to be critical to the long-term
track of Matthew. The UKMET and ECMWF tracks have shifted westward
and slower by day 5, while the GFS has trended east. This has
narrowed the guidance envelope somewhat, but given the lack of
run-to-run consistency I'd hesitate to say that confidence in the
long-range track forecast
has increased by any appreciable measure.
The new NHC track at these times leans heavily on continuity, and by
day 5 is close to the GFS/ECMWF blend and left of the latest
multi-model consensus aid TVCN.
It is important to remind users that average NHC track forecast
errors are around 175 miles at day 4 and 230 miles at day 5.
Therefore, it is too soon to rule out possible hurricane impacts
from Matthew in Florida."
I tend to stick to the NHC for my information because, as seen in the statement above, they use a combination of models to arrive at (what their forecasters) believe to be the best explanation of what they've seen so far, and hence what to expect the atmosphere to evolve into.
That they stress the uncertainty of their predictions of both track and intensity gives, for me anyway, a degree of confidence in their predictions.
Intensity is by far the hardest to predict, according to he NHCs' own admission, and performance, but it seems to me that they have improved immensely, almost exponentially (OK that's a little exaggeration) in their track predictions in the last 10-15 years...
That being said, it appears that this storm may be especially problematic, both track-wise and to a somewhat lesser extent intensity-wise, given the slow moving, almost stationary (at this time) low pressure systems over the southern great lakes
and the Mideast coastal states.
The lack of much pressure gradient in the maps shown below, a typical feature for late summer in our area, might give a little insight into why both track and intensity are hard to predict at this time...
According to the latest satellite
imagery, the storm is currently about 10 degrees across in it's 'sphere of influence'. In the last 7 hours or so, the eye appears to have moved about a degree to the north-northwest, or about 60 miles. Maybe this signals the beginning of the expected turn to the north, maybe its just an artefact of the cyclonic looping behavior this storm has been exhibiting after reaching major status... I'm hoping it is the former; the sooner it turns, the higher the chances are that it will move more to the east and remain (mostly) at sea.
However, the poor people of the Haitian peninsula, eastern Jamaica
are poised to get a beating, flash-flooding and rain pose a larger threat than the (relatively) isolated high winds. I hope they are prepared, but they are in a hard place right now...
On the current
proposed track, the storm is expected to be due east of Abaco
and slowing, on Sunday, after re-strengthening to a category 3 and passing directly over the central Bahamas. It then shows a slight turn to the west, so everywhere on the central US east coast
had better start preparing, especially given the possibility for further strengthing. Maybe we'll be lucky and the persistent low/high system in the area will push on to the east in time to let the storm pass safely to the northeast...but forewarned is forearmed.