Recently changed from light Sleet / Snow between 06-09hrs to Rain from
12hrs then back to Sleet from 15hrs....

TAF EGKK 201707Z 2018/2124 24013KT 9999 FEW030
BECMG 2106/2109 16008KT
BECMG 2112/2115 8000 -RA BKN014 PROB40 2115/2118 4500 RASN
BKN008
BECMG 2118/2121 3000 BR BKN004

Regards

Richard Griffith
Horsham AWS

Richard G wrote:
Recently changed from light Sleet / Snow between 06-09hrs to Rain from
12hrs then back to Sleet from 15hrs....

TAF EGKK 201707Z 2018/2124 24013KT 9999 FEW030
BECMG 2106/2109 16008KT
BECMG 2112/2115 8000 -RA BKN014 PROB40 2115/2118 4500 RASN
BKN008
BECMG 2118/2121 3000 BR BKN004

Regards

Richard Griffith
Horsham AWS

Richard, its all on a knife edge..Heathrow has a Prob40 of Heavy Snow..
EGLL 201707Z 2018/2124 24013KT 9999 FEW030 BECMG 2107/2110
16008KT BECMG 2113/2116 8000 -RASN BKN014 PROB40 2116/2120
1200 SN VV/// BECMG 2118/2121 3000 BR BKN004=

Its going to be a fine borderline between SN and RA and I think thats
the way its going to be for the next 72 hours...good luck the medium
term forecasters!

Phil

--
Guildford, Surrey

www.layton.me.uk/meteo.htm

"Phil Layton" wrote in message
...
Richard G wrote:
Recently changed from light Sleet / Snow between 06-09hrs to Rain from
12hrs then back to Sleet from 15hrs....

TAF EGKK 201707Z 2018/2124 24013KT 9999 FEW030
BECMG 2106/2109 16008KT
BECMG 2112/2115 8000 -RA BKN014 PROB40 2115/2118 4500 RASN
BKN008
BECMG 2118/2121 3000 BR BKN004

Regards

Richard Griffith
Horsham AWS

Richard, its all on a knife edge..Heathrow has a Prob40 of Heavy Snow..
EGLL 201707Z 2018/2124 24013KT 9999 FEW030 BECMG 2107/2110
16008KT BECMG 2113/2116 8000 -RASN BKN014 PROB40 2116/2120
1200 SN VV/// BECMG 2118/2121 3000 BR BKN004=

Its going to be a fine borderline between SN and RA and I think thats the
way its going to be for the next 72 hours...good luck the medium term
forecasters!

Phil


That's just moderate snow this time, Phil, otherwise I'd agree, it's another
tricky one.

The (unmodified) 12Z NAE rain/snow discrimination field shows the potential
problems later tomorrow
http://www.weatheronline.co.uk/cgi-b...0&ARCHIV=0&WMO

Given the recent talk about 1000/500mb thickness it's perhaps interesting to
note that this snowfall is likely to occur in air slightly warmer than
528DAM.

Jon.

In article ,
Jon O'Rourke writes:
The (unmodified) 12Z NAE rain/snow discrimination field shows the
potential problems later tomorrow
http://www.weatheronline.co.uk/cgi-b...en&MENU=000000
0000&CONT=ukuk&MODELL=nae&MODELLTYP=1&BASE=-&VAR=prty&HH=36&ZOOM=0&ARCH
IV=0&WMO

Given the recent talk about 1000/500mb thickness it's perhaps
interesting to note that this snowfall is likely to occur in air
slightly warmer than 528DAM.

Fascinating. If I interpret that correctly, it looks as if it may have
influenced the forecast on the BBC just before 8pm, which tentatively
suggested that the Chilterns and east Midlands might have snow.
--
John Hall "[It was] so steep that at intervals the street broke into steps,
like a person breaking into giggles or hiccups, and then resumed
its sober climb, until it had another fit of steps."
Ursula K Le Guin "The Beginning Place"

"John Hall" wrote in message
...
In article ,
Jon O'Rourke writes:
The (unmodified) 12Z NAE rain/snow discrimination field shows the
potential problems later tomorrow
http://www.weatheronline.co.uk/cgi-b...en&MENU=000000
0000&CONT=ukuk&MODELL=nae&MODELLTYP=1&BASE=-&VAR=prty&HH=36&ZOOM=0&ARCH
IV=0&WMO

Given the recent talk about 1000/500mb thickness it's perhaps
interesting to note that this snowfall is likely to occur in air
slightly warmer than 528DAM.

Fascinating. If I interpret that correctly, it looks as if it may have
influenced the forecast on the BBC just before 8pm, which tentatively
suggested that the Chilterns and east Midlands might have snow.
--

Most certainly, John, as the BBC graphics and forecasts are driven by NAE
data up to T+48. I would just add that there can be differences between the
raw data and that which the BBC uses depending on the extent of the
modifications made by the chief forecaster. In situations like this it may
to change the type of precipitation and hence can be quite significant.

Jon.