Category Archives: Commentary

Commentary

HURRICANE FLORENCE COMMENTARY

The flooding and devastation brought by Hurricane Florence continues in the Carolinas.

I wanted to just weigh-in on the forecasting aspect of the storm.  I haven’t heard very much credit given to the real meteorologists, mathematicians, and scientists that developed such remarkable computer models of the earth’s atmosphere.

The computer models did incredibly well with the precipitation forecast and early/late track of this storm and its remnants.   Possibly the best I’ve seen in recent years.

The new GFS-FV3 model, still in trial mode (to replace the current GFS and become operational in January 2019), also did very well.

While the intensity forecasts are generally unreliable, and were off  with this storm, (it luckily hit the coast as a category 1 instead of the previously forecast category 3-4), the rest of the forecast was very impressive.

Thank you to the National Weather Service and their scientists!

 

Commentary

SO WHAT’S WITH THIS COLD WEATHER?

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People are asking me, what’s with this prolonged winter weather and cold?

One thing not talked about recently is the solar cycle.  We are about to enter a solar minimum.   The solar cycle is a regular, periodic change in sunspot number and the mimimum correlates with reduced total solar irradiance.

The solar cycle repeats ever 10-11 years.

The SORCE PROJECT has been measuring the total solar irradiance since 2003.

SORCE project total solar irradiance
SORCE Project Total Solar Irradiance

The previous solar minimum was in 2009.  The minimum has been shown to have a total solar irradiance that is reduced by about 0.5 -1 watt/m2.  Over the surface of the entire earth, that reduction adds up.

Maybe you’ll recall that the summers of 2009 and 2010 were usually cool?  I think the coming summers of 2018 and 2019 might be similarly cool.   (We’ll find out!)

So if it’s a cool summer, remember, it may be the sunspot cycle.

BTW, Here’s a link from my old blog in 2009 talking about the solar cycle.

Clarification 4-14-18: When I say cooler weather, it doesn’t mean we won’t have heat waves.  But it means that there will be fewer days in the 90s and average temperatures for the months of June July and August may be just below average.

Commentary

SNOWSTORM POST-MORTEM

My previous post included the link for the official snow totals. I always like to evaluate my forecast to improve on future forecasts.

For the immediate PHL area, snowfall was between 7-11 inches and areas  somewhat further north and west, totals approached 15 inches.

With my call of 4-7 inches with an emphasis on “7 most likely”, my forecast fell short.  So what happened?

Official QPF measured at the airport yesterday was 1.06 water, somewhat higher than the 0.87 predicted by the NAM and higher than the GFS. But overall the models did well on QPF. (The actual snow total for just Wednesday was 6.7 inches at PHL airport, according to the NWS.)

My emphasis on solar insolation through clouds lead my forecast astray.  Had it been January, I would have predicted 8-10, which I mentioned in several posts.  So I learned yesterday that heavy snowfall rates trump solar effects, even in late March.

While the models did well on QPF, they did less well on wind. That was lucky for our region.  Temperatures were predicted well.

Mesoscale banding set up northwest of the city and snowfall was heavier in those areas.

I’m ready for Spring!

Final Two day snow totals