Posted by: coastlinesproject | October 22, 2012

Tropical Storm Sandy, one model has it heading well offshore the other toward the DelMava peninsula.

TD 18 is becoming better organized and is likely to become Tropical Storm Sandy within a day or so.
The short range track forecast for Sandy is pretty well agreed upon by the forecast models with the center
passing through Jamaica Wed, eastern Cuba Thurs and the Exumas on Friday.  With warm water in place
and not much shear, Sandy should steadily increase in strength until it encounters stronger shear
on Thursday or Friday.The bulk of the forecast models curve Sandy eastward and out to sea after Friday.  However, the most reliable models of
the group (GFS and ECMWF) still hint at the chance of a more westerly track.  The EC today, like yesterday, has Sandy
backing up to the west and the GFS ensembles have a plurality of members showing a westerly track although the
mean of all ensemble members is much further east.

The differences in the forecast depend on the location and alignment of a disturbance dropping out of Canada
and into the US Midwest late in the weekend.  To the extent that this disturbance is “progressive”, meaning fast moving
from west to east, it will guide Sandy offshore.  That’s the majority solution at this point.  But if the disturbance “cuts off”
over the Midwest, it  will stall like a spinning top and the steering winds will pull Sandy northwestward.

Here’s what the progressive solution looks like – Sandy well offshore:

(Wrong maps, sorry)

and here’s what the cut off solution looks like – Sandy off Delmarva.

Loading Maps...

-- 
William F. Ryan
Department of Meteorology 
The Pennsylvania State University

"If we begin with certainties, we will end in doubt, 
but if we begin with doubts and bear them patiently, 
we may end in certainty"
Francis Bacon

Read more in Storm surge, and Beach Wars. See UPne and Strawberry hill tabs at the top of this page.

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