Re: [WR] Cold Langtoft

• From: "David Mitchell" <david@xxxxxxxxxxxx>
• Date: Wed, 1 Feb 2006 22:12:23 -0000

"Will Hand" <will@xxxxxxxxxxxxxxxxxxxx> wrote in message 
news:drr8cm$qsm$1$830fa79d@xxxxxxxxxxxxxxxxxxx
>
> "David Mitchell" <david@xxxxxxxxxxxx> wrote in message
> news:44cls6F1iibdU1@xxxxxxxxxxxxxxxxx
>> Temp fell below 0c just before midnight, but was stable until 0440 then 
>> fell
>> continuously until the min of -2.9 at 1540. Currently stands at -1.8.
>> The Wolds are shrouded in hill fog with rime on the highest hills this
>> morning, but this had lowered to 500 feet by evening.
>> Can anyone give me an explanation about today's cold please?
>>
>> -- 
>> David Mitchell, 70m amsl, Langtoft, East Riding of Yorkshire.
>>
>>
>
> OK here we go!
>
> Due to the low cloud top and fairly thin cloud and time of year (low sun 
> angle)
> the short wave radiation from the sun could not overcome the longwave 
> radiation
> from the cloud top, hence the cloud top cools. Weak convective overturning
> within the cloud eventually cools the cloud base as heat is re-distributed 
> from
> base to top and then out into space and possibly giving light drizzle or 
> snow
> grains (as in Leeds). Cooling the cloud base chills the air as longwave
> radiative fluxes from cloud base to ground decrease. (Cloud acts as less 
> of a
> blanket).
>
> Isn't physics wonderful!
>
> Will.
> --
>
> " Ah yet another day to enjoy "
> -------------------------------------------------------------------------------
> A COL BH site in East Dartmoor at Haytor, Devon 310m asl (1017 feet).
>
> mailto:      will@xxxxxxxxxxxxxxxxxxxx
> www: 
> www.lyneside.demon.co.uk/Haytor/automatic/Current_Vantage_Pro.htm
>
> DISCLAIMER - All views and opinions expressed by myself are personal
>             and do not necessarily represent those of my employer.
> -------------------------------------------------------------------------------
>
>

Will. Thank-you for that fantastic explanation.
It's great that I can thank you publicly, as some people would not have 
bothered to reply to my post, having had a forecast criticised by self same 
poster in the recent past.
I gues that's why you're the professional and I the mere amateur!

-- 
David Mitchell, 70m amsl, Langtoft, East Riding of Yorkshire.


.

• References:
  • [WR] Cold Langtoft
    • From: David Mitchell
  • Re: [WR] Cold Langtoft
    • From: Will Hand

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