Thursday, March 15, 2012

Chilled Along The Coast, Milder West Today

We're not as mild this morning as past mornings -- the combination of light winds, clear skies, and the slightest bit of cooler, stable air crawling down from the northeast has given us a cooler start than the past two mornings.  Early temperatures are in the 40's across much of the region, with some 50's in Delaware.  Today is going to be a "fun" day from a forecasting perspective.  Warmest temperatures today will be south and west of Philadelphia -- 70 to 75 is possible in Dover and Reading, while 50's are likely for highs along the coast in New Jersey from AC on north.

Some variant of 60's look likely for just above everyone else -- Philadelphia should top out around 67 if everything breaks right but there's a ten degree difference in the two main computer models regarding temperatures today for Philadelphia -- the warmer guidance is low 70's and manages to keep a sea breeze limited to near the coast, with the cooler guidance in the lower 60's and developing some lower clouds that hang out across portions of the city for a time during the day.   In reality, something in between these two goalposts takes hold.  We will see sunshine inland, some low clouds along the Jersey coast for a time this morning before they thin towards midday, before clouds move in from the west later on this afternoon for everyone in advance of the next storm system that moves through tonight.

Breezes will nudge from the east and southeast today as high pressure slides off the coast, generally around 5 to 10 miles per hour.  With ocean temperatures in the upper 40's to near 50, that's just enough cool water to work with to help prevent some areas from making a run at 70 that would give us our first "warm wave" in March since 2010 but when the average high at this time of the year is in the lower 50's, 67 is still a good bit above average.

Showers and drizzle are possible later tonight with low pressure moving through the region.  A rumble of thunder can't be ruled out west of the city but with the influence of stable air off of the Atlantic precipitation may end up being more drizzly and thunder chances may be rather limited.  Those shower chances will continue into Friday.

The good news is that the cooler NAM guidance is shifting towards the GFS and Euro...and removing the threat for a malaise of rain and rawness.  Some sun is possible at times tomorrow and the potential for the warm front associated with this low to clear most of the region, allowing for a return to 70ish temperatures for the city, suburbs, and immediate South Jersey.   Could be tough to coax out warmth at the Shore but 60 to low 60's certainly is a reasonable call there on Friday.