Sunday, December 28, 2014

Freeze alert

Expect widespread frost early Saturday.

Freeze alert

The government has a complicated nomenclature to advise us of various atmospheric perils from heat waves, to snowstorms, to that holiday favorite -- the wintry mix.

Sometimes we wish that for days like this the National Weather Service had a parallel ssytem to alert us to weather we should savor -- perhaps "Sky Blue Advisory," or "Savor Day" alert.

We see nothing of that sort on the weather service site this afternoon, but the agency has posted a "freeze watch" for late tomorrow night and early Saturday for most of Pennsylvania, including Bucks, Chester, and Montgomery Counties.

The forecast calls for temperatures dropping into the upper 20s and lower 30s north and west of the city.

The forecast low for Philadelphia is 37, nowhere near a record, but a temperature more common around Thanksgving.

Generally, that first freeze, defined as 32 Fahrenheit reading at Philadelphia International Airport, has been showing up later in recent years.

In 2011, two days after that snowstorm, the temperature bottomed out at 31, the first time since 1992 that the freezing point was reached in October.

In the first decade of the millenium. the average first-freeze date was Nov. 14.

That was a full three weeks later than the freeze date of the 1960s. The earliest freezing reading on record occurred on Oct. 5, 1961.

But we should point out that the first-freeze date in the first decade of the 20th Century and the 1920s actually was later -- Nov. 16.

Temperatures should rebound nicely on Sunday on what should be a magnificent day, and the Climate Prediction Center continues to favor above-normal temperatures through the 25th.

Tony Wood Inquirer Weather Columnist
About this blog

Everyone talks about the weather, and here we write about it.

When we’re around and conditions warrant, we’ll keep you updated about what’s coming, but we will do our best always to discuss weather and climate developments in context and remind you that nothing in the atmosphere happens in a vacuum.

Tony Wood has been writing about the atmosphere for The Inquirer for 26 years.

Reach Tony at twood@phillynews.com.

Tony Wood Inquirer Weather Columnist
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