It May Be Spring, But...

 The calendar and meteorology both say it's "Spring" by definition -- in fact in a meteorological sense it's been Spring for over 20 days.   However, Mother Nature and Old Man Winter don't care to agree with such silly wishes of warmth from most of the masses and wants to send a plethora of precipitation types into the region tomorrow.    Radar is already showing the first fingers of the storm system extending into West Virginia, with the main show of this storm back in Minnesota and Wisconsin.   Moisture that's streaming out east-southeast of the main low is in association with a frontal boundary that's slipping south along the East Coast and will play a huge factor in the storm's track, our temperature, and what ultimately falls from the sky.

This will not be an easy forecast -- the dreaded "nowcast" applies to this storm as temperatures at the surface will arguably make or break your precipitation type and one's forecast.   However, with temperatures poised to be colder to the north that at least some accumulating snow is likely from Montgomery and Bucks County on north, particularly the upper parts of the county.   I'm not so convinced that applies to the city...yet...but I do think it's pretty likely that the city does get some wet snowflakes mixing in.   It all comes down to timing and temperature with this event.   More on that in a minute.

Winter Storm Watches are out for the Lehigh Valley and Berks County on north -- the watches in the Poconos definitely make sense given the profile in temperatures is going to be cold enough for mostly frozen precipitation up there although one can't rule out some rain mixing in from time to time during the day on Wednesday up north.  The Lehigh Valley and Berks, in my opinion, are the "battle zone" where a colder solution such as the one the NAM is painting gives warning snowfall since little or no mixing at the surface occurs.  However, it is the only model painting that as the Euro and GFS both paint a mixed bag event where morning snow mixes and then changes to rain during the day as temperatures warm sufficiently above freezing in most locations.    The surface warming above freezing is the difference between a couple of inches of front-end snow and a six inch snowfall in the Lehigh Valley and even the upper parts of Bucks and Montco.

Farther south, the temperature profile battle as not as huge a deal but the NAM's depiction on temperatures would suggest some snow down into the immediate city on the front end before temperatures moderate enough aloft to turn the city back to rain, whereas the GFS and Euro are more of a mix to rain scenario.

The other concern is how this system wraps up on Wednesday night.  The NAM is suggesting a changeover back to snow in the suburbs, Philly, and even parts of South Jersey but again, it's the only model showing this changeover as the GFS and Euro both wrap precipitation up in the region before temperatures begin to cool off.   It's something to keep an eye on at this point.

Even if it doesn't snow at all in the city, the temperatures won't be all that high and the rain will be rather chilly.  

We'll have a snowfall forecast out this evening for the storm system and we'll update the storm as it moves through during Wednesday.