Saturday, February 23, 2013

March Will Begin Chilly For Eastern Half of US

For those who like late season cold weather and love delayed Spring, the next couple of weeks will be all about you.  The next storm system in the pike -- Tuesday's soaking rain event -- will likely set up a cut-off troughy pattern over the Northeast, leaving a chilled regime of cool to cold air across much of the eastern half of the country as blocking in the Atlantic prevents the storm system from chugging on out into the Atlantic.

The result is that February for us will likely end up below average on temperature in Philadelphia -- our second colder than normal month in the last four locally (only the fourth such month since the beginning of 2011) and that March will start like a chilled and unsettled lion across the East.  The West will get a significant warmup that will carry them for the first week of March.

The core of cold in the US will actually reside in the Southern US -- temperatures could be over ten degrees below average in parts of the South at the end of this week if the GFS' model projection is close to correct.  The core of cold stays south and doesn't move completely over the East...but we will deal with unsettled and generally cooler than average weather through the first week of March.   Keep in mind the average high the first week of March in Philly is in the upper 40's -- a good bit milder than the averages of five weeks prior so temperatures could still hover in the low and mid 40's (plausible for highs) next week and we sit in a stale airmass of chill.

As for hintings of bigger storms -- the pattern in theory could support something developing in the Atlantic that would probably benefit New England more than it would benefit us in Philadelphia.  That said, modeling isn't showing anything noteworthy at this point other than spits of rain and snow showers around the region, one on Thursday night and another chance on early Saturday of next weekend.  Unsettled seems to be the general rule, with breezy and chilled conditions common.  Whether that spits anything more than a few showers of rain and snow remains to be seen but nothing "big" has shown up on the models for a couple of consecutive runs.

We may see this pattern transition towards warmer after the week of March -- the long, long range of the GFS shows the potential for a fling of Spring around mid month. Perhaps our first 60's in the region since January?