Saturday, March 31, 2012

Modeled Differences In Pattern But Nothing Too Unseasonable

Tomorrow's system could bring another bout of thunder with the associated showers as it pushes through the region during the later afternoon and evening hours.  This system, while minor as it moves through tomorrow with little more than a few showers or a thundershower, will be the dominant player in our weather pattern in eastern North America for the beginning of April as it develops into a stronger storm system once it moves away from the US East Coast.  The low pressure system will push northeast and then north to become a bit of a "50/50" low off of Newfoundland for the beginning of April as a strong ridge of high pressure exists in the Central Atlantic Ocean.   This ridge is blocking eastward progression of any storm systems and instead forces them north.   There isn't much in the way of ture cold that will be forthcoming.  In fact, the pattern is shaping up as pretty typical.  The only difference is when we work towards Easter and how the pattern evolves to that point.

I have two mid range predictions -- the Euro (above) and the GFS (below), which show some differences for temperatures in the April 5-9 time frame -- generally next Thursday through the Phils' home opener.  The biggest difference in the pattern comes from the evolution of tomorrow's storm as it gradually works towards Newfoundland.  The Euro computer model predicts the storm pushes north into Greenland and breaks the Central Atlantic ridge down somewhat, allowing a ridge of high pressure to gradually nudge into the Ohio Valley and East Coast for the end of next week and the Easter weekend.  Temperatures in this scenario would gradually warm but we're not looking at "epic" warmth for us in Philly -- 70 would not be out of the realm of possibility for Easter IF the Euro solution is right.

On the other hand, the GFS takes this low and stalls it over Labrador, setting up a bit of a -NAO look that would sustain itself into the Easter weekend as a trough dominates over the eastern parts of North America.   Temperatures for the latter portions of next week and into the Easter holiday would be near to slightly below average, while the ridge that the Euro projects moving into the Ohio Valley would instead camp out over the Plains and Midwest before getting squeezed down thanks to this upper low.   The Euro shows a much shorter duration...and much more fleeting...eastern trough next week in comparison to the GFS.  Under the GFS, you're looking at near 60 degree weather for Easter -- very similar to what we had yesterday...nice, but a cool start to the day.

Regardless of solution, no "big" storms are on the horizon.

The pattern itself seems to be more variable this month -- although after next week we could see a mid-month warm spell that could bring a shot of 80 degree weather back into the region towards Tax Day.  While still very far out in the future, modeling is hinting a bit at this warm up taking place mid month.