|35 Years Ago - Winter of 1976-1977 Brings the Coldest Temperatures Ever to the Area
While this winter has been a far cry from a
typical winter in the Ohio Valley, a look back at mid-January through
mid-February of 1977 makes us realize how lucky we've been with the
warm temperatures and infrequent snowfalls.
The period of
January 10th through February 8th 1977 represents the coldest
30-day period ever recorded in Cincinnati, Columbus, and Dayton when
considering the average daily temperature (average of high and low over
a 30-day period). This brutal stretch of weather has been the
measuring stick for any Arctic outbreak since, and so far only a
similar brutal stretch in January 1978 comes close to matching the
bitterly cold temperatures for such a long duration of time.
|City||Coldest 30-Day Avg Temperature Ever (F)||Period||Coldest Minimum Temp During Period|
|Columbus||10.4||Jan 10th - Feb 8th 1977||-19|
|Cincinnati||11.4||Jan 10th - Feb 8th 1977||-25|
|Dayton||10.6||Jan 10th - Feb 8th 1977 ||-21|
-25F for a morning low temperature at Cincinnati referenced above
occurred on January 18th, 1977, and represents the coldest morning low
temperature in official records. In fact, the previous morning (January
17th 1977), Cincinnati dropped to -24F, tied for the second coldest low
temperature in official records for the Queen City.
Below are more interesting stats from this frigid 30-day stretch..
|City||# of Morning Lows < 0 (F)||Avg. Snowdepth||Snowfall During Period|
Weather PatternWhat led to this extreme period of cold temperatures? A very amplified pattern,
meaning troughs of low pressure and ridges of high pressure at all
levels of the atmosphere were far stronger than normal for the time
period. The Ohio Valley, unfortunately resided underneath an extremely
strong and deep trough of low pressure, what was in fact a very
displaced Polar Vortex, which
is a feature common in most winters over higher latitudes in Canada.
Below is a chart of the average deviation from normal of the 500mb
surface through this period. Hues of purple indicate that these 500mb
heights were significantly lower than normal, in some cases over 200
meters below normal. These values are extremely significant and rare
when considering a 30-day average. This overall weather patten is
the ideal setup for outbreaks of frigid air in the eastern United
States. A west coast ridge of high pressure (yellow hues) and
extreme blocking (very strong ridge of high pressure in red hues) just
off the east coast of the United States near Greenland.
pool of Arctic air was just as impressive - and as you can see in the
image below of 850mb air temperatures deviations from climatological
normal (about 5kft above the surface of the Earth), the core of the
coldest air in comparison to normal (purple hues) was centered directly
over the Ohio Valley.
The Ohio Historical Society has compiled a brief, but very interesting webpage on this period.
- Seth Binau, Science and Operations Officer (firstname.lastname@example.org)