Daily Archives: Thursday, March 11, 2021 5:28 pm

Philadelphia Weather Outlook

WEEKEND WEATHER PREVIEW & DAYLIGHT SAVING TIME

A cold front will move through around daybreak Friday. Light rain is expected with the frontal passage (less than 0.20 inches).

Skies are expected to clear after the frontal passage and should remain sunny and cooler Friday.  A secondary cold front moves through early Saturday. 

The weekend should be mostly sunny, windy and cooler although some cloudiness is possible during part of the day Sunday as a weak upper air disturbance moves through.  High 48-50º Saturday and 53-56º Sunday.

The fairly dry weather pattern is expected to continue.

Of course, Sunday morning is the beginning of Daylight Saving Time.  I love the extra daylight at the end of the day, but for “weather people”, Daylight Saving Time means the models come out an hour later. (Weather models are run at UTC – Coordinated Universal Time).   For “weather people” on  Eastern Daylight Time, the models really come out a little too late!  I’ve written extensively about this in past years—

Little Known Facts about Daylight Saving Time and TV Weather Forecasts

Daylight Saving Time and Weather Models

“Check Back at 11” TV weather and Daylight Saving Time

The new GFS version 16 launches on March 17th. Due to the increased complexity of the new model, (there are new parameters and it’s computed at many additional levels -layers of the atmosphere), the GFS v16  will take an additional 8 minutes to compute its forecasts.  Several models that depend upon the GFS for their “initial conditions” will also run later.   

That means the GFS model’s next day forecast (for the next 24 hours) won’t be available until 11:45-11:50 PM EDT, way past the 11 o’clock TV news and past bedtime for most of us!