Busy Weather Pattern Continues for U.S.

Click for larger image.

Click for larger image.

We’ve already touched on the snowfall in Colorado and Minnesota, but snow isn’t the only story of this latest storm system.  Rain, and plenty of it, is currently falling across the southern Plains.  This will spread north and east, bringing about the chance of flash flooding in southeastern Kansas, eastern Oklahoma, and eastern Texas.

Rain is also falling in the Pacific Northwest.  Snowfall from this system is expected in the higher elevations of the Canadian Rockies.

It will be a beautiful day across the Ohio Valley, mid-Atlantic, and southeast U.S.  High pressure will help create mostly sunny skies and temperatures should rise a little above normal.  Here in the D.C. area, we’re expecting temperatures to top out in the mid-70s this afternoon as well as tomorrow.  The cold front associated with the low moving across the Plains should begin pushing through the east coast this weekend.  Temperatures are forecast to cool off a bit, but nothing like what we experienced last weekend.

Looking into the future, it appears the busy weather pattern will continue.  The preliminary extended forecast from the HPC shows a series of storms making their way through the U.S. over the next seven days.  Here’s the series of maps for the extended forecast:

Click for larger image

Click for larger image

Three separate cyclones are forecast to move through the U.S. during the forecast period.  The first cyclone is associated with the snow and rain currently falling across the Rockies and southern Plains, respectively.  A second cyclone is forecast to traverse the northern Plains on Sunday with a third cyclone passing through nearly the same area early next week.

Now, these are only the preliminary graphics in an extended forecast.  So, there is definitely uncertainty surrounding them.  Do you know what’s even more uncertain?  10-day forecasts.  They’re terribly unreliable.  There’s almost no point in putting any stock into what they might say.  In fact, I would say their only value is pure entertainment.

Click for larger image.

Click for larger image.

To quote Gladiator, “Are you not entertained?”

Well, perhaps if you have young children who are looking to trick-or-treat in a light-weight costume you may not be enthralled with this forecast.  Do not be afraid – at least not yet.  Much can, and likely will, change between now and Halloween.  I would be stunned if it were this cold 10 days from now.  Still, when I saw it this morning, I couldn’t resist.  I buried at the bottom of the post for a reason, though.

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2 Responses to Busy Weather Pattern Continues for U.S.

  1. hstraus says:

    I think one of the major reasons for such erratic long-term forecasts is the topography, particularly over the Rocky mountains; the models simply can’t account for that factor very well. What model was this forecast made with?

    • Steve J says:

      This is from the GFS model. After 7 days (180 hours), the spatial and temporal resolution of the model is decreased, which tends to enhance inaccuracies in the solution. For this reason, trusting any forecast beyond 7 days is questionable at best. This is why I used the term “entertainment.” 🙂

      The Rockies are taken into account in the model grid, but the terrain is smoothed to an extent. This can certainly affect the forecast for surface features such as low-pressure centers and precipitation. For example, in this current storm, the model will struggle to resolve the heavier precipitation on northeast-facing slopes. On the other hand, it shouldn’t affect troughs and ridges in the jet stream since it is located well above the highest peaks in the atmosphere.

      Those meteorologists working in the mountain west need to have extensive local knowledge to accurately predict the weather. Simply looking at computer models is not sufficient. They need to understand the relationship between model solutions and how it affects their local region. When these cyclones move east into the Plains and toward the east coast, computer models can better handle the dynamics of the storm as well as the aforementioned surface features.

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