Re: [WR] Cold Langtoft

• From: "Rob Overfield" <rob.overfield@xxxxxxxxxxxxxxxxx>
• Date: Wed, 1 Feb 2006 21:25:35 -0000

Will Hand wrote:
> "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?
>>
>
> 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!

Thank Will.  For the first time in a while, I actually understood most of
that!  Have to admit, I was wondering the same question over the 6.25 BBC
forecast so well done David for asking...
--
Rob Overfield
Hull


.

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

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