Dec 22, 2013

This morning's crazy weather or why Andy has more grey hair!

Here is another "look" at this mornings "unbelievable" weather (freezing rain in some places, rain in others and temperatures below freezing in some spots with record warmth in others)!

The first image is a "normal" or "typical" temperature plot versus height - temperatures usually decrease with increasing height. The temperature plot slopes from the lower right of the SkewT to the upper left.  A SkewT is a thermodynamic diagram that enables one to plot temperature, moisture (and wind, too).

The temperature scale is at the horizontal axis at the bottom of the chart. Temperatures are colder to the left of this axis and warmer to the right. The horizontal scale is the height and pressure (above ground level). Pressure decreases with increasing height.

The image below to the lower right is a plot of the actual  temperatures and moisture aloft over Albany, NY (at 7AM EST/22 DEC). on a SkewT diagram.

The dashed red line is the dew point temperature. The red line is the air temperature. Note the temperature curve: it slopes from the lower left of the diagram towards the upper right. That is to say temperatures are INCREASING (NOT decreasing with height). The DEPTH or height of the cold air is BARELY 500 hundred feet thick!

The next image is an interval listing of the Albany data. Note the temperature at approximately 1,260 feet above the ground (at Albany) : +10.3° C or 51°F. This why the higher elevations are warmer than the valleys.

Why is that the Hudson Valley is colder? 

Well across southeast Canada and Northern NY State and New England there is a strong arctic high pressure system.  Thanks to a nearly perfectly aligned windflow from the NNE, as shown on the mesoplot below,

some of this very cold and dense air was able to "drain" down the Champlain Valley into the Lake George Basin then into the Hudson Valley.

Why does Andy have more grey hairs?

Because of all of the above!!