Updates on Friday/Saturday Storm

Much like with Hurricane Sandy, the EURO weather model picked up on a weather system well in advance and has not wavered in days.  The American GFS has joined the party and is now forecasting a major snowstorm meanwhile the EURO ensembles may be more impressive than the operational.   What all that means is a major, potentially crippling Nor'Easter will impact the region on Friday.

(Note- I pay very little attention to 06/18z models past two days.  Data is same used in 00/12 suite forward 6 hours.  Large errors occur in the long range)

A clipper system will enter the US tomorrow and track through the Great Lakes dropping up to a foot of snow (lake enhanced) in Western Michigan.  Meanwhile heavy rain and thunderstorms will develop along the Gulf Coast tomorrow as energy from the southern jet is tapped.   This will move northeast dumping heavy rains across the South and steadily gaining strength as it reaches the Carolina coast.

EURO Thursday 7 PM (image wxbell)

Several things will happen as these two systems approach the east coast.  First of all the Gulf Coast system will begin to strengthen as it feeds off the Gulf Stream. The clipper will phase into this, making the storm even stronger.  Yesterday I said I would not show the EURO snow totals from last night's run.  Well there have been two runs of the model since and nothing has changed. 

(Note- not my forecast, rather a reliable computer model's projection)

00z EURO 96-hr snow totals (image wxbell)

That is a widespread 2 feet in gray.  The American GFS likes around 8 inches in Worcester

00z GFS KORH Citygram (image wxbell)

The heaviest snow looks to hold off until after noon time on Friday.  I'm going to hold off on an accumulation map for now, I'd like to see the GFS and EURO converge on snowfall amounts.  At this range I expect a foot plus for much of Southern New England.  

Relative Measure of Predictability 

There is high confidence in a trough in the west and high pressure over the Great Lakes.  Note the low confidence in the depth of the eastern trough.  This is one of the final details to work out.  The National Weather Service is not screwing around, they have already hoisted Winter Storm Watches for much of Massachusetts (sans SE MA, but they will get there).

Winter Storm Watch in effect Friday-Saturday

More later, including a post on the Blizzard of 78.  Its been 35 years since that storm set the benchmark for Southern New England Blizzards.