Below freezing yet melting?

[Keith (Southend)]

Here in Southend-on-Sea the rain turned to snow about 8am and the air temperature went below freezing about 11am and has hovered between -0.2 to -0.3°C since. Dew Point has been in the range of -0.6 to -1.1°C.

However, it has not really settled on hard surfaces, my raingauge has very slowly continued tipping ever half hour or so and even the grass it appears to be melting.

My take on it is three fold.
1. It was wet before it turned to snow.
2. Dew point temperature not a lot lower than air (High humidity)
3. Heat from sun getting through the clouds. (2) should drop later.

Just wondered if anyone had any other thoughts?

Keith (Southend)

[Julian Mayes]

Hi Keith, 

As it happens I was just looking at the road-weather sensors across Essex.  It is striking from these how 'warm' the road surfaces have become in the last 2 hours  (2-3C) compared with the decreasing air temps   - these are now widely below zero and falling.  It may partly be radiation balance but also consider the soil temperature - heat flux up to the surface.  It has been mild quite recently.  Do you measure soil temps?   This conduction of heat is a major factor for forecast models predicting road surface temperature - road weather sensors have sensors embedded 30 cm below the road surface to record this 'deep temperature'.   

Julian  

[Keith (Southend)]

Good point Julian. No I don't record soil temperatures. Only two days ago I recorded 10.8°C and it was really quite warm in the sunshine, plus we haven't had a frost to push any of theat surface temperature doen since.

Many thanks

Keith (Southend)