Monthly Archives: March 2017

Philadelphia Area Weather Forecasts

Philly Weekend Weather Forecast

Saturday Update 8:30AM: Today’s surprise is that the low doesn’t look like it will develop as deeply as previously forecast.  That means less precipitation and less cold air being brought in.  Just light intermittent rain showers today and especially this evening.  Too warm for snowflakes.

As mentioned the other day, a weak disturbance moving along a frontal boundary will develop a surface low pressure system when it reaches the coastline.  With these scenarios, there are occasionally surprises in either direction; sometimes the low is much stronger than predicted and sometimes weaker.   Here’s the current model forecast:

Light snow will likely develop later tonight, giving us a coating by morning.  Very light snow changes to light rain and  continues on and off during the day Saturday, with an increase in intensity late afternoon and early evening.  High temperatures around 42.  (Average high is 55.)

There may be a shift back to wet snow early evening, then light snow through Saturday night, ending Sunday morning.  Another coating, up to an inch, is forecast by Sunday morning.

Light snow ends very early Sunday morning and skies clear by afternoon.  Temps remain below average with a high of 44.

[stbpro id=”info” caption=”Extended Range Forecast”] Despite Spring arriving on Monday, the extended models are showing at least two more outbreaks of cold weather. [/stbpro]

Philadelphia Weather Outlook

Light Snow Possible for late Saturday in PHL

A weak low pressure disturbance will move along a frontal boundary just to our south late Saturday afternoon.

There are increasing signs that a last minute intensification will occur as the disturbance reaches the coastline.

If this occurs  in the evening rather than during the daytime hours, the high March sun angle won’t be a factor and some snow accumulation is possible.  Current NAM QPF values are about 0.33 inches water.  Current thermal profiles support the precip falling mostly as snow, but light QPF in March can be difficult to accumulate, unless it occurs at night.

Each recent successive model run has shown slightly greater intensification.    Not a sure thing, but it needs to be watched.

The long range models are suggesting a continued overall somewhat cold  pattern with another deep cold outbreak the end of next week, followed by moderating temperatures.