Sandy…Make Up Your Mind!

October 24th, 2012 at 9:19 am by under Weather

Al Roker had a great graphic on the Today Show this morning showing the difference between the 2 possible tracks of Sandy.  It is similar to one that I built, but it had one big difference.  He had the distance between the main 2 models (European and American or GFS).  It was over 700 miles.  700 miles!!!  I’ve ranted about this over the past couple of months that it seems like this has been a recent trend in the last couple of years with this large divergence during big storms…. Anyway it is possible that we could see some big impacts here in the viewing area, and we do have to keep in mind that it is still pretty far out.

Tropical Satellite

For now Sandy is a strong tropical storm and it will probably become a weak hurricane very soon.  This morning it already had winds of 70mph.  It was moving north at 14mph.  So it has definitely picked up speed.  The pressure was down to 986 mb (millibars).  The storm is forecast to move across Jamaica and Cuba as a weak hurricane.  There will likely be some flooding in those countries.  Then it will move over the Bahamas as a strong tropical storm.  This will cause many problems for that region, as well as for many vacationers taking advantage of the Fall rates.  There is a pretty high confidence that Sandy will move north/northeast through early Saturday.  As it make it up to about the latitude of central Florida then it is forecast to move more to the northeast as upper level winds push the storm in that direction.

Forecast For Sandy

The models diverge quite a bit at that point.  Most of them push the storm off towards Bermuda.  There are a couple which bring it up very close to the coast.  Too close.

Computer Forecast Models

The European model has gone against every other model lately except for the Navy (NOGAPS) model.  They both run the storm very close to the coast.  The European has done a good job over the last couple of years, but the NOGAPS has not.  And the latest run of that is scary.  Either way this closer-to-the-coast scenario will cause quite a few problems.  I would equate it to some of the MODERATE Nor’easters that we had in 2006.  Not the big nor’easter of 09′.  These created some minor to moderate tidal flooding in the region and heavy rain.  One was in the late Summer from a tropical system. Another was in October.  The third was around Thanksgiving.  This would play out probably between Sunday into Monday.

Closer To Coast Scenario

This would also produce very heavy rain as the cold front to the west stalls out near the region and butts up against the tropical moisture.  This would be heavy enough to cause flooding in itself aside from the tidal flooding.  There would probably be some surge along the Outer Banks directly from the storm, but the Chesapeake Bay could see tidal flooding with a couple of tidal cycles having strong northeast winds.

The other scenario is for the storm to swing well offshore.   The bulk of the models show this situation in the longer term, but some of them do curve the storm back to the northwest into the northeast states ie. Massachusetts.  The GFS has been showing an offshore forecast for several model runs.  It also has been doing good with tropical systems over the last couple of years.  If it follows the offshore scenario, then we can expect some high waves, perhaps some minor tidal flooding and overwash along the Outer Banks, scattered showers along the cold front, and breezy northeast winds.

Offshore Scenario

Again, the bulk of the models show this offshore scenario, but it is the history and consistency of the European model that is causing the concern.  If I didn’t look at that model, then I would have a very false sense of security at the moment.  So again… Sandy…make up your mind.  Or at least the models should.

I mentioned yesterday that Sandy will probably go right in between these two forecasts.  It would probably curve back into about Maine if it did.  The impacts wouldn’t be too bad in that scenario, but we would notice the storm for sure.  Especially along the Outer Banks.  We are going to have more updates through the day.  Until Sandy moves across Jamaica and Cuba, we’ll probably have a low confidence in the long-term track.  That is unless the models start to agree more on a common solution.

Meteorologist: Jeremy Wheeler

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