January Thaw is Nothing New - NBC 10 Philadelphia

January Thaw is Nothing New

Warm air coming through as it has over the past 100 years



    Inside Weather: January's Warming Up

    Glenn talks about the large thaw on the way. (Published Monday, Jan. 11, 2010)

    The cold air that's been in place across our area may have you chilled to be bone, but never fear because it's not going to be frigid much longer.

    A large area of warm air is poised to move east by the end of this week bringing with it temperatures in the 50s and a winter thaw, says chief meteorologist Glenn "Hurricane" Schwartz.

    "Now it's not going to automatically warm up to 60 degrees, it may not get to 60 degrees for a while but we've probably seen the last of the zero degree wind chills," he said.

    It's all part of the January Thaw -- the real name for a warm period that has been occurring in Philadelphia over the past 100 years.

    "We don’t know why it's there, but it's there and the patterns changing just in time for it…again," said Glenn. "Even averaging out temperatures over a 100 year period, there's a significant upswing in temperatures between the 20th and 27th of January."

    In Philadelphia, this month's temps have hovered around 4 degrees below normal, which Glenn says is a "pretty significant departure" from the norm. The cold has been so persistent thanks to a blocking pattern, but that's about to break.

    "By next week, the pattern will be more typical of a strong El Nino winter. That means unseasonably mild air over much of the eastern two-thirds of the country," Glenn said. "Computer models suggest that by the 20th to 25th, temperatures will average about 10 degrees above "normal" -- meaning an average of about 50 for highs.

    Great relief for now, but there's no guarantee on how long the warm air will stay.

    "It is still possible for the pattern to get cold again in February, since El Nino years usually feature cold Februaries," Glenn says.