Wednesday Weather Discussion

The talk around town has been about the potential for some snow this weekend.  That option is still on the table and I’m only a little bit closer to figuring out how significant it will be.  There are two separate model camps emerging.  The global American GFS and global EURO model keep the system largely offshore.  The global Canadian, UKMET and short-range high-resolution American NAM all have a more significant storm.  I certainly favor the EURO as it has the best track record but the other solutions are interesting and plausible.  Let’s discuss.

Short Range Forecast

The cold front that brought rain and scattered power outages last night has pushed offshore.  Temperatures have fallen into the low 40’s.  Tonight they will fall into the upper 20’s overnight in the coastal plain and low to mid 20’s across the interior.

WPC Forecast Surface Fronts/Precipitation Wednesday 7 PM

Temperatures tomorrow will be right around normal.  Highs will range from the upper 30’s to low 40’s.  Skies will be partly cloudy with a bit of a west wind.

NWS Forecast Max Temps Thursday (image Weatherbell)

Temperatures on Friday will likely struggle to get out of the 30’s as the Arctic air begins to make its way into Southern New England.  Temps Friday AM will be in the upper teens and low 20’s.   Sunny skies in the morning will transition to clouds as the next storm system approaches.

WPC Forecast Surface Fronts/Precipitation Friday 7 PM

The Weekend

As I mentioned in the opening, there has been no clarity to the forecast from this morning’s guidance.  The differences are subtle as all guidance agrees on the general pattern.  An upper-level trough will dive south, perhaps bringing winter weather as far south as New Orleans!   Low pressure will track northeast from the South Atlantic states off the northeast coast.  First up let’s look at the GFS.

The GFS

Here is the GFS Saturday at 1 PM at the surface.

12z GFS MSLP Saturday 1 PM (image Weatherbell)

The low is kind of stretched out and suppressed pretty far offshore (relative to making an impact on the weather for most of Southern New England).   The Western Atlantic ridge is pretty far offshore and the trough in the east is weaker, especially in the Southeast.

12z GFS 500 mb height anomaly Saturday 1 PM (image Weatherbell)

The CMC (GEM)

The Canadian, on the other hand, is much closer to the coast with its surface low and stronger.

12z CMC MSLP Saturday 1 PM (image Weatherbell)

At the mid levels. the CMC has a stronger shortwave ejecting out of the Southeast.  The ridge in the western Atlantic is also closer to the east coast.  There is more of a northerly component to the jet stream instead of a northeast component like the GFS and EURO.

12z CMC 500 mb height anomaly Saturday 1 PM (image Weatherbell)

The difference between these two solutions is a plow-able snow across Worcester County or just a few snow showers.  The GFS and EURO bring 2-4″ of snow across SE MA, coastal RI, and the Cape.   I still think 1-3″ is possible in Southern Worcester County.  It would be nice to get some agreement in the forecast models by this time tomorrow.

Summary

Odds favor a light snowfall from Worcester County east on Saturday afternoon into the early evening.  Though not likely, a larger storm cannot be ruled out.  A complete miss cannot but ruled out either.  I’m buying 1-3″ in Worcester area with 3-6″ possible in SE MA/Cape.  Temperatures will be in the low 30’s.  More snow chances will follow next week.

We’ll talk again tomorrow.

-Zack Green

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