Caution: Wintry Mix Could Surprise to the Upside Late Tonight & Tomorrow

radar

The latest radar image out of the Ohio River Valley shows some moderate to heavy rain falling.  This will need to be monitored closely as the current forecast is based on the premise that temperatures may not dip as low as we had thought and the precipitation would come in bouts of drizzle or very light precipitation.

The latest HRRR (High Resolution Rapid Refresh) model is latching on to the current conditions (as far as precipitation goes) better than some of the various models I looked at earlier this afternoon.  The dew point at Dulles is currently sitting at 21 degrees.  With the dry air in place and some evaporational cooling (when precipitation falls through dry air and initially evaporates causing the temperatures to cool)… this “train track” of moderate precipitation will need to be watched very closely.  

If temperatures do in fact drop off into the upper 20s to near 30 and this band of heavier precipitation “trains” over the metro area late tonight into tomorrow… we may end up seeing higher ice accumulation.  

Also, if the precipitation can begin as snow and come down at a moderate clip (likely a wet snow)… some folks could indeed pick up one to two inches before the change over to ice.  This is something to watch… the models are not perfect… this is a very tricky forecast.

The image below shows the latest High Resolution Rapid Refresh (HRRR) between 1 and 7am Saturday:

  • A more moderate bout of steady precipitation could increase our snow, sleet and freezing rain amounts. Something to watch.

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2 Replies to “Caution: Wintry Mix Could Surprise to the Upside Late Tonight & Tomorrow”

  1. Looking even more interesting! We could be lokking at more widespread slick roads. Since this band developed, do you think the weather service will up their totals inthe advisory products?

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    1. The precipitation stayed well south of the area overnight preventing the wet bulb effect from happening… hence temperatures in the lower to middle 30s with Rain. We dodged a bullet. I hate ice… so I’m happy we just got Rain. Parts of our Area are still in a moderate drought. So any rain we can get is a good thing.

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