Friday, March 22, 2013

Mix of Sun & Clouds This Weekend

The forecast for the upcoming period is a bit of a glass half full or glass half empty situation.  On one hand I don't see any snow.  On the other hand temperatures are going to be in the 40's.  The strength of the cold air is actually going to suppress the storm track to the south.  We've had our fair share so they can have it.  I'm sure some of you have seen the photo on Facebook or Twitter of the church who posted on their sign "Whoever is praying for snow please stop!"

Current Conditions/Observations
It is still snowing on the Cape this morning as our interacting systems continue to feed off one another.
NWS Boston radar 6 am
Here is the surface chart
WPC surface analysis 330 am
You can see the low southeast of New England.  Here is the 500 mb chart
06z NAM 500 mb vorticity 2 am EST
There is a closed upper level low in Southern Ontario.  There are two pieces of energy working with it.  The max south of New England is responsible for the low pressure at the surface.  Its not very strong, but it does not have to be.  Here are snow totals from SE MA
NWS Boston Skywarn Snow Reports 3/21-3/22
That is 9.5 inches in Acushnet, MA.  In general there is 3-6 with lighter amounts as far north as Worcester where officially a trace of snow fell.  If it snowed then obviously its cold out there again.  Here are the current temps
5 am 2 m temps (image weatherbell)
The Jet Stream just does not want to move back north.  Here is the Jet Stream this morning
06z NAM 250 mb Jet Stream 2 am
Why is the jet being so stubborn?  It's mainly the AO (Arctic Oscillation), with an assist from the NAO (North Atlantic Oscillation).  Both the AO and NAO are extremely negative.  When the AO is negative the jet usually dips in the US.  When the NAO is negative in late winter/early spring extreme blocking takes place so patterns are able to stay in place for a long time.  

Weekend Forecast
Overall the weekend will be alright.  A high of 45 on Sunday will likely feel pretty good.

Friday- Highs close to 40 along coast and SE MA.  Highs in upper 30' elsewhere.  Mix of sun and clouds.  Light wind 10-15 MPH from west

Friday Night- Lows in the low 20's.  Partly cloudy skies

Saturday- Mostly Sunny. Highs in the low 40's.  Winds increasing to 15-20 mph with gusts to 30.

Saturday Night- Lows around 20 in the interior and north of Pike, upper 20's in RI, CT, SE MA

Sunday-  Mostly Sunny. Winds relax a bit 5-10 mph from NW, temperatures in the mid 40's.

I don't think we see a storm on Monday or Tuesday.  Guidance that has been showing a storm have trended south. I'll watch it over the weekend.  Happy Friday!






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