Monday, November 5, 2012

The midweek Nor’easter

There's no doubt we will have a Nor'easter Wednesday afternoon into Thursday. But, what is in doubt is the track and timing. Both of these things will have a huge impact on who sees what. I would have posted this on my Facebook weather page ; but every time I try to make an album FB post the image separately.      

The upcoming Nor'easter will be moderate to strong. But at this time, it won't be anything like the Halloween Nor'easter we had last year, while it will bring some strong winds especially on the coast , it's not going to be anything close to Sandy.

Map of path
Here is a quick map I drew. It shows the Where our Nor'easter is sitting a Midnight, Just off of British Columbia. The track will carry it southeast and have it off the Southeast Coast Late Tuesday or early Wednesday. The storm will then move up the coast phase with the polar and subtropical jet and rapidly intensify by the time it gets into the Northeast.

gfs_namer_078_1000_500_thickGFSShowingwindon thewestside
  Here's the GFS it's showing a moderate storm of 988mb. It's running a little faster than most of the other models. It has the Nor'easter South of Long Island Wednesday in the 1:00 - 200: am timeframe and moving across New England during the morning on Thursday. It's more to the east than the other models would bring snow for Cape Cod.

Wind3285032and32mslp_North32America_96EUROruning a few hours behind the CMC
This is the Euro. It's running slower than the other models. It tracks the Nor'easter to the east of Delaware Maryland then moves it south of Long Island and moves it into New England. it also phases the storm and jet stream sooner.

Here is the GGEM it's a Canadian model. it's the most aggressive of the models and shows a strong Nor'easter . It has the track a bit more to the east than the ECMWF (EURO).

Here is Canadian CMC it has a track that is more or less in between the Euro and the GFS. The panel in the upper right is the 1000-500 Thickness Chart.....The chart I posted on the other day. It looks different than the GFS thickness chart that I showed you how to read....but you will see it gives the same information.                      


Another model called the MRF the Mid Range Forecast Model. As you can see all the models say we will have a coastal storm…but where is the big question.

Potential impacts from this coastal storm could include:


 They will have Gale Force winds (50+ mph) on the coast, some coastal flooding and beach erosion ( not great news after the massive erosion caused by Sandy).

If you look at all the models they are showing a tighter pressure gradient on the west side of the storm. So during the overnight and into Thursday, inland areas will see some wind as well. In higher elevations the winds could gust up to near 45 mph. But it will be breezy in the lower terrain as well. One threat would be trees and limbs weakened by Sandy would be at greater risk of coming down.  


The coastal areas will see heavy rain. This would cause flooding of poor drainage areas. In Central and Eastern NYS the lower elevations below 1000 feet will most likely see rain.    


Most likely the rain will turn to snow during the overnight going into Thursday morning. The Precip would be heaver on Thursday. How much is the 100 dollar question at the moment. The Nam, Canadian, along with the GFS have the Nor'easter to the east. In fact the latest run of the NAM is looking more like the GFS. However, the ECMWF has it very close to the coast. The Track will most likely be east of the Euro and West of the others. If you look at the Models and the Map I drew you will see there is a large area of  strong high pressure north of the Nor'easter in Canada. This would help in the cold air department as long as the Nor'easter tracks close enough to the coast. If the Euro is right Eastern New York would see a big hit. with Central New York seeing some snow as well. On the other hand, the GFS would basically be a complete miss. With the GGEM, Canadian, and NAM more of a New England event.  

Elevation: will play a role, areas above 1000 feet will have the best chance of seeing snow. From 1000 - 1500 feet it could be a snow/sleet mix. The areas above 1500 feet would have the best shot at seeing enough snow to make it a plowable event, especially in the Catskills and parts of the Capital District (if the track is right).  As you can see there is still a lot to iron out. Namely how cold it will be, timing, and the track of the storm. So it's too early to make any snowfall forecast at this time. It does look like the precipitation will be later in the day Wednesday and going into Thursday. I'm fairly sure the Catskills will see snow, as will those above 1500 or 1800 feet in southeastern NYS. The lower elevations will see mostly rain, with those between the two seeing a snow, sleet mix. As for how much, I just don't know yet.

That's it....I know it's not much.....there is just too much uncertainty to say anything else. I hope to have a better handle on this by tomorrow sometime.


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