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Pro Update: Computer model trends November 7

Several computer models advertising an early-season winter storm kickstarted the hype machine on Wednesday. 2011 and 2012 both featured early snow storms in Southern New England, and the prospect of a third straight year with snow before Thanksgiving had social media buzzing. So, what’s the latest on the potential for a Nor’easter in the middle of next week? Let’s take a look at the computer model trends.

GFS Model

After a few consecutive runs with a whopper storm for the Mid-Atlantic and Northeast, the 12Z November 7 run on of the operational GFS kept the storm offshore with NO impact in Southern New England. Basically, the newer run is a lot quicker with the shortwave disturbance heading for the East Coast in the middle of next week. It has a large area of high pressure moving southeast from Canada and the storm that forms off the Carolina coast moves northeast away from the coast. Prior runs had the trough sharpening up before reaching the coast. The result was a slower-developing storm that hugs the coast as it moves north late next workweek.

Prior run (left) has a storm hugging the coast. New run (right) sends the storm out to sea in a progressive pattern.
Prior run (left) has a storm hugging the coast. New run (right) sends the storm out to sea in a progressive pattern.

Prior run (l) is a lot slower with the energy reaching the coast. New run has a progressive trough that moves offshore and takes the storm with it.
Prior run (l) is a lot slower with the energy reaching the coast. New run has a progressive trough that moves offshore and takes the storm with it.

Brrrr! The high temperature may struggle to reach 40° in Southern New England in the middle of next week.
Brrrr! The high temperature may struggle to reach 40° in Southern New England in the middle of next week.

ECMWF Model

The ECMWF (European) model latched onto a stormy solution with its 00Z November 7 run. The operational run brings a major early-season Nor’easter to the Mid-Atlantic in Northeast. The track of the storm is close enough to the coast that there is more rain than snow in Southeastern New England. This solution is drastically different from the most recent GFS run, and it will be very interesting to see what the ECMWF shows in its 12Z November 7 run due Thursday afternoon. We’ll update the graphics when it comes in. In the meantime, check out the epic 00Z run.

UPDATE: The 12Z ECMWF is a huge departure from the GFS. It has a slow-moving strong storm that whips the East Coast with wind and rain. It brings very heavy snow to the Appalachians from North Carolina to Northern New England. Southeastern New England gets rain and wind.

00Z November 7 ECMWF - heavy rain in Southeastern New England
00Z November 7 ECMWF – heavy rain in Southeastern New England

12Z November 6 ECMWF - The model was not buying a big storm at this point
12Z November 6 ECMWF – The model was not buying a big storm at this point

00Z November 7 ECMWF - Big time snow totals in the Mid-Atlantic and Northeast
00Z November 7 ECMWF – Big time snow totals in the Mid-Atlantic and Northeast
ecmwf_uv10m_neng_32
00Z November 7 ECMWF – Strong winds with a Nor’easter



00Z November 7 EPS - Not all ensemble members were on board with a storm. Ensemble mean precipitation about half of the operational run
00Z November 7 EPS – Not all ensemble members were on board with a storm. Ensemble mean precipitation about half of the operational run

12Z November 7 ECMWF - Storm moves slowly and hugs the coast.
12Z November 7 ECMWF – Storm moves slowly and hugs the coast.

12Z November 7 ECMWF - Heavy snow for the Appalachians
12Z November 7 ECMWF – Heavy snow for the Appalachians

12Z November 7 ECMWF - Strong winds near the coast. Persistent onshore winds lead to coastal flooding and beach erosion.
12Z November 7 ECMWF – Strong winds near the coast. Persistent onshore winds lead to coastal flooding and beach erosion.

12Z November 7 ECMWF - 1-2" of rain in Southern New England
12Z November 7 ECMWF – 1-2″ of rain in Southern New England

Canadian Model

The latest run of the Canadian model is closer to the latest GFS than it is to the ECMWF, but it’s overall solution is an outlier. The Canadian has the storm develop in the Atlantic Ocean at the same time that the Arctic cold front is crossing Southern New England. The storm begins on Tuesday and ends by midday Wednesday. While the progressive pattern has merit, the timing seems too quick. Also, the precipitation with the Arctic front seems overdone in the Northeast. The center of the storm is way offshore, and a more likely scenario would have one round of rain/snow showers Tuesday followed by dry weather.

The previous run of the CMC model had some showers with the Arctic front, but no sign of the storm in the Atlantic Ocean. Now it’s seeing the potential for a storm, but it may be too quick with developing it.

The Canadian model is picking up on the storm potential, but the timing may be too quick.
The Canadian model is picking up on the storm potential, but the timing may be too quick.

The Bottom Line

The jury is still out on this one! The NAO is positive, and the progressive solution would seem most likely. That would mean a miss for SNE, with dry and chilly weather through the midweek. However, the ECMWF has a good track record in the medium range, and the latest run has a cut-off storm system that lashes the East Coast with wind/rain. It brings snow to the interior Northeast. It should also be noted that while the operational GFS jumped off the storm bandwagon, there are some ensemble members with a solution close to the European model.

GFS Ensemble 12Z November 7 - some members show a big Northeast storm
GFS Ensemble 12Z November 7 – some members show a big Northeast storm

Fred Campagna

President and Chief Meteorologist - Right Weather LLC AMS Certified Consulting Meteorologist #756 AMS Certified Broadcast Meteorologist #126

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