Tuesday, March 13, 2012

Damp, Raw Friday On Horizon

The party can't last all March. There needs to be some madness...some variety...some less than stellar weather mixed in our mild regime at some point to add a little bit of variety to our spice of meteorological life. While the next couple of days will remain dry, sunny, and above average in the temperature department, we will see things nudge downward from a temperature standpoint over the next couple of days as "less warm" air is part of our forecast.  Still, 60's to near 70 isn't too bad for either day.  Thursday may feature a bit of a sea breeze in the afternoon as the influence of a southeast flow ahead of low pressure may help nudge some cooler air off the Atlantic...and it wouldn't surprise me to see temperatures on Thursday only get to the 50's along the coast before dropping back in the afternoon.  It is March, after all.

The aforementioned low will cross the region on Friday with a round of rain in what is likely shaping up as the coolest day of the coming week.  The NAM depiction below for 8 AM on Friday shows scatterings of rain across Pennsylvania -- the best chances of rain will likely be Friday afternoon and evening locally.  It isn't, as of now, shaping up as a soaking rain but a quarter to half inch type event in general.

Friday brings us the most temperature uncertainty and there's potential we end up a bit cooler than what the majority of models are projecting (which is upper 60's and lower 70's for highs).  The combination of east and southeast breezes off the Atlantic (NAM graphic below shows the wind trajectory from the southeast) and moisture ahead of the low pressure center probably may result in a marine layer setup ahead Thursday night into Friday morning, with cool & stable air moving in off the coast and lots of low clouds around.  We could end up with a damp, drizzly Friday before rain moves in.  If the damp and drizzly conditions do set up, I wouldn't be shocked if we only top out in the 50's on Friday afternoon.   If the surface wind is a bit more south to southwest, those 60's to even 70's are certainly do-able...and the GFS is certainly a bit more aggressive on trying to nudge those winds to a warmer direction as it wants to lift a warm front ahead of the low through Philadelphia.  

For what it's worth -- the NAM has waffled a bit towards the milder guidance for Friday in its more recent runs this afternoon but it's not a consistent look as of yet -- so Friday's temperature projections are very uncertain and could be revised quite a bit higher should we need to go there.  The best chances of cooler weather on Friday and north and east of Philadelphia while Delaware should end up pretty mild.

The good news is that this is a one day event -- Saturday should feature improving weather with temperatures poised to nudge back above 60 away from the Shore (might be some upper 50's at the Shore with residual clouds and an on-shore flow there).   Even milder weather is in store for next week...and our talk about possibly seeing 80 degrees at some point early next week is still on the board...with Tuesday or Wednesday of next week the possible "best chances" for it occurring.