Hourly 4 inch (0.1m) Soil Temperatures|
The image below (click on it to enlarge) shows the hourly 4 inch soil
temperatures at 6 locations across central North Carolina from midnight on
February 28 through midnight on March 6, 2010.
First note that this winter storm was preceded by a few mild days
with temperatures reaching the 40s to lower 50s on 02/28 and
in the lower and mid 50s on
03/01. During this warm period the 0.1m (4 inch) soil
temperatures reached the lower to mid 40s during the late afternoon hours.
The amount of diurnal and spatial variability in the data is
also interesting with some location experiencing diurnal spreads of more then 10
Note the limited diurnal recovery on 03/02 given the expansive cloud
deck which results in soil temperatures in the upper 30s to lower
40s just before the precipitation arrives. Once the precipitation begins during
the midday and afternoon hours on 03/02, the soil temperatures
begin a gradual drop through the evening and overnight hours.
Past experience has shown that when max soil temperatures during the day preceding a
snow fall are in the lower 40s or colder and given modest snow rates with surface temperatures at or near
freezing, the snow can be expected to accumulate. While soil temperatures were a little
warmer then these guidelines, the heavy snow rates in the Triad during the afternoon and overnight across
Randolph, Chatham, and Lee Counties allowed the snow to accumulate fairly quickly.
NCAT - NC A&T State University Research Farm, Greensboro NC
HIGH - UNCG Lindale Farm Station, High Point, NC
CLAY - Central Crops Research Station, Clayton, NC
GOLD - Cherry Research Station, Goldsboro, NC
REED - Reedy Creek Field Laboratory, Raleigh, NC
SILR - Siler City Airport, Siler City, NC