Category Archives: PHL Climate Forecasts

Winter Climate Outlook for Philadelphia

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It doesn’t take much climate science background to identify that this years’s current weather pattern is very different than the last two years.

While past winters were possibly affected by the diminished solar cycle peak and the random blocking patterns that set up for unknown reasons, one recognized climate influencer is the El Ninio Pacific Ocean  temperature cycle.  With current Paciific Ocean water temperatures at an extreme peak, the El Ninio will over-ride any other recognized patterns or climate “oscillations” that otherwise affect our climate.

The official NOAA Climate Center has predicted a warmer and wetter winter for our area this winter, based on the El Ninio, and that sounds righ to to to me.  Expect periods of very warm weather (the upcoming weekend a good example), but there will still be periods of cold.   (Hey, it’s winter.).    Expect mostly big rain storms, but a big snow storm could still be possible.

Right now, it appears that the warm pattern stays with us through the middle of December.  Current models suggest that the more recognizable winter weather cold temperatures arrive here about December 17th.

Madden-Julian Oscillation

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Last year, the meteorological term that was in vogue was “polar vortex”, something that always exists but like a spinning top, can sometimes spin eccentrically off the main polar axis giving us bitterly cold weather.  As I noted in a previous climate forecast, this year looks very different.    The vogue climate phrase I expect to see this year will be the Madden-Julian Oscillation (MJO)

For the coming week, the large scale weather phenomenon that is causing all that rain on the west coast will give us warmer than normal temperatures.  This large scale climate phenomenon is associated with a certain phase of the Madden Julian Oscillation– warm moist tropical convection (thunderstorms) in the Indian Ocean and Pacific  that slowly migrates eastward and affects the US.   Most noticeable during lulls in the El Nino cycle.

This usually brings heavy rains to the west coast and can result in deep storms in the Eastern US as a result of a natural “wavelength” to the jet  stream.    This is what is speculated to be what’s happening with the heavy rains in California and the deep low that just affected us.  These phases last 30-60 days, so a wet and milder pattern will likely be with us for much of the remainder of this month.  The next “phase” of the MJO isn’t expected until late December or early January, so cold weather may return.  This phase of the MJO is simply a bias towards wet and warm and the East coast effects are less deterministic.

Philadelphia Fall Winter Climate Outlook

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It’s time to make my annual fall forecast.

I always start my climate forecasts with a reiteration that climate prediction is very different than weather forecasting despite the appearance that they are similar. It’s an inexact science.

That said, there is an overwhelming allure among professional and amateur forecasters to attempt to predict trends in weather based on current weather patterns. So here goes.

It appears that we are experiencing a pattern change from the cold and wet pattern we had over the past year. We have just passed the second peak of the current solar cycle. This would signal a warm period for us, but the recent solar cycle expectedly peaked at a low level.

Nonetheless, we are beginning to see a pattern reminiscent of our last solar peak– increasingly dry conditions in the NE and milder temperatures. An increasing El Niño complicates the tendency towards much drier weather, but the current pattern suggests the solar influences will trump the El Niño influences.

So my climate forecast for this fall and early winter is for drier conditions and warmer milder temperatures. It doesn’t mean we’ll not see rain or snow or cold periods, but expect temperatures above average and almost drought conditions here in the NE.