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Verification of Experimental Seaonal Summary Forecast for UK area, DEC JAN FEB (Winter) 2012-2013

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How well did the experimental forecast do? - not too bad overall.

OBS data from UKMO near normal temps but slightly below over much of central and eastern of UK, with CPC data shown near or slightly below normal temps:

NOVEMBER 2012 DATA: Correct signal from UKMO although well below normal signal not so good, NASA and Russia also gave colder than normal signal although forecasts of near normal were also almost correct.

OCTOBER 2012 DATA: UKMO also gave correct colder signal but possibly over cold signal.

PPN totals above average in many central and SW parts as well as NE England and E Scotland. Drier than normal NW Highland, Cumbria and parts of west N Ireland

NOVEMBER 2012 DATA: Poor forecast from all, no capture of below normal PPN (small hint in NMME) and little consistent signal for wetter areas.

OCTOBER 2012 DATA: Better signal from several systems for drier across the N and wetter in S.


NOVEMBER 2012 DATA

2012 Dec 2013 Jan Feb
Summary - UK again favouring a colder than normal winter with some support now from Russia, NASA and KMA output
FSU slightly above, NCEP normal. (see caution in Sept and Oct summary). Main theme is Dec and Jan colder with Feb milder than normal but unsettled.
Bit of a shift to pressure being higher in and to S hence more mobile across the N with PPN higher than normal across the N and lower in E of England. IRI initial weak above normal
signal often shows above normal temps perhaps supports the colder theme. CFS2 was slightly warmer than CFS1 so here again the normal indication may back up a colder theme.


DATA sourced by country.
UK 12Nov2012
TEMP: Prob for above average 20-40% in southern half UK less than 20% in N. Probs for below normal 40 to 60%. Prob for well below normal
25 to 40% but for Northern and Western Isles and N/NW Scotland 40-55%.
PPN : 40 to 60% probs for above normal in N. Elsewhere similar probs +/- or normal except 40 to 60% prob below normal E / SE England.
25-40% probs for well above normal N and well below in E/SE England.
PMSL: Above normal in and to the to S of UK.


USA <- NCEP CFS1 discontinued
USA - NCEP CFS2 07Nov2012 mean of last 10 runs
Temp:
Seasonal - nosig difference from normal
Monthly - all months nosig difference from normal
PPN :
Seasonal - Above normal, 0.2-0.4mm/day but in SW, Wales W and NW England and SW Scotland 0.4 to 0.6mm/day.
Monthly - DEC; N and NE England normal elsewhere above normal, SW England and SW Scotland more so 0.6-0.8mm/day.
JAN; N Ireland N Scotland and NE England normal, otherwise above especially in west.
FEB; N and E/SE Scotland NE England and E of England normal, elsewhere above normal especially SW Scotland and Wales.

USA - GSM FSU 06Nov2012
Temp: Slightly above normal (persisted SST gives S Scotland, N Wales and Midlands north over England slightly below)
PPN : Slightly above normal but Midlands and E England slightly below. (Persisted SST: generally above normal especially S Scotland, Ireland, N England and fat N Wales)

USA - IRI 15Nov2012
Temp: Above normal probs 40 up to 45% in Scotland, Wales and England except E/SE. Normal 35% and below 25% to 20%.
PPN : No sig deviation from normal.

NASA GMAO GSFC 08Nov2012
Montly data suggests colder than normal lifting well above in Feb.
TEMP: Seasonal: Nosig from normal. Monthly data: Dec; Normal but below normal for Wales, midlands and S of England. Jan; Normal but S Scotland, Wales and England (except far SW and S) below normal.
Feb; N Ireland above normal elsewhere well above normal.
PPN : Seasonal: Nosig from normal. Monthly data: Dec; Normal but below normal in SW and S. Jan; Normal but below normal in NW Scotland. Feb; Normal but well above normal in NW Scotland.

Russia 02Nov2012
Temp: Generally below normal temps (50% up to 70% prob in SE England), except locally coastal far SW Wales and W Cornwall where near normal.
PPN : Uk part of broad area of below normal rain (>50 to 60% prob).

Korea KMA
PMSL: DEC: On average below normal pressure. JAN: above normal across the N with slightly below in the S of UK. FEB: Generally lower pressure than model climat average.
Temp 850hPa: DEC: Sig colder than normal. JAN; Colder than normal, especially in East. FEB: Milder than normal
PPN APCC 26NOV2012 : DJF Near normal
T2M APCC 26NOV2012 : DJF Near normal/slight favour above normal nearby Atlantic.

Japan JMA 15Nov2012
Temp:
Season=Main signal is for near normal 35% (but below normal 30% and above normal 25%) but for England equal probs +/-/normal.
Month= DEC: near ir slightly above normal JAN: Near or slightly below normal. FEB: Near or slightly below normal.
PPN :
Season=Wales and SW slight favour for above normal. N Scotland slight favour for below normal. Nearer equal probs elsewhere.
Month= DEC: Slightly below normal ecept N Scotland slightly above. JAN: normal but slightly above in N. FEB: near or slightly above.


Multi Ensembles USA. 07Nov2012.

USA IMME (International multi model ensemble) - NOV data
TEMP:
DJF Season; Normal in E/SE England otherwise slightly (0.25 to +0.25C) above normal.
JFM Season; Slightly above normal.
FMA Season; Slightly above normal.
Monthly - DEC; Normal JAN; Slightly above normal. FEB; Slightly above normal. MAR; Slightly above normal. APR; Normal.
PPN :
DJF Season; Normal (anomaly range -0.25 to +0.25 mm/day)
JFM Season; Normal
FMA Season; Normal
Monthly - DEC; Normal (anomaly range -0.25 to +0.25 mm/day) but SW England lightly below normal (-0.25 to -0.5 mm/day).
JAN; Normal (hint NW Scotland slightly above 0.25 to 0.5mm/day). FEB; Normal (hint NW Scotland slightly above). MAR; Normal. APR; Normal.



USA NMME (National multi model ensemble. CFSv2 CMC1 CMC2 GFDL NCAR NASA) GFDL not included as of 07Nov2012
TEMP:
DJF Season; Normal.
JFM Season; Normal.
FMA Season; Normal.
Monthly - DEC; Normal (Anom +/- 0.25C). JAN: Slightly above normal (0.25 to 0.5C) but SE England normal. FEB; Slightly above normal.
MAR; Slightly above normal. APR; Normal.
PPN :
DJF Season; Normal.
JFM Season; Normal.
FMA Season; Normal.
Monthly - DEC; Normal but NW Scotland slightly below normal (-0.25 to -0.5 mm/day). JAN; Normal but SW England/SW Wales slightly above. FEB; Normal

OCTOBER 2012 DATA

2012 Dec 2013 Jan Feb
Summary - A risk of a cold winter indicated by UK and some other output but overall spread suggest nearer normal. Precip details uncertain.


DATA sourced by country.
UK
TEMP: Main signal for below normal temps (60 to 80% prob) Scotland, N Ireland, N England, Wales and SW England, elsewhere above 40%.
Enhanced probs for well below normal England, E Wales and S Scotland 25 to 40%, elsewhere above 40%.
Continuation of Sept output for below normal temps - caution model hindcast period 1996 to 2008 was a "warm period" overall.
PPN : Reduced probs for above normal rain across the N, otherwise normal PPN. Slightly favoured probs for below normal PPN across the
N and E with slightly enhanced probs for well below normal in these areas.
PMSL: Enhanced probs for above normal pressure across the N of UK (on average).

USA - NCEP CFS1 MONTHLY replaced by CFS 2 after October 2012
TEMP:
DEC: Below normal except far N. Probs for England and Wales 45 to 55%
JAN: Mostly normal, N Ireland slightly above.
FEB: Near normal

PPN :
DEC: Mostly below normal indicated 45 to 55% N Ireland, S Scotland and N England
JAN: Near normal but in S of England above normal indicated 35-45% prob.
FEB: Near normal but southern third and northern third below normal slightly favoured.

USA - NCEP CFS2 MONTHLY
Temp:
DEC: near normal
JAN: near normal
FEB: S third of UK above normal otherwise normal.

PPN :
DEC: SW Scotland and SW England above normal
JAN: Much of England, Wales and SW Scotland above normal otherwise normal
FEB: Much of W and N England, Wales and SW Scotland above normal, normal elsewhere.

USA - IRI
Temp: 40% for above normal, 45% NW Midland and E Scotland also far NW Scotland.
PPN : No departure from normal indicated

NASA GMAO GSFC

TEMP: Anomalies slightly positive
Dec: Very slightly above normal, but Highland Scotland milder.
Jan: Very slightly above normal, milder along M4 corridor?
Feb: Slightly below normal but N Ireland near normal

PPN : Slightly below normal in S and slightly above in N.
Dec: Near normal but W and NW Highlands above normal
Jan: Near normal, perhaps above normal parts of S Wales and SW England.
Feb: Near normal, slightly below across NW Highlands.


SEPTEMBER 2012 DATA


2012 Dec 2013 Jan Feb
Summary - A cooling trend in some output may add some weight to a colder late winter/earl spring.

DATA sourced by country.
UK
TEMP: Colder than normal. < 20% for above normal temps but SE third of UK 20 to 40%. Signal for below or well below normal temps - unusually high probs for well below.
PPN : Hints at well above normal parts of SW Englnd and far NE Scotland. Mostly 40 to 60% probs for above normal but reduced in NW Highlands. Again signal for less Precip in the NW.

USA - NCEP CFS1 MONTHLY replaced by CFS 2 in July 2012
TEMP: Dec: Near normal, below in places. Jan: Near normal. Feb: N Ireland, much of Scotland above elsewhere below.
PPN : Dec: normal to slightly above in S and W. Jan: normal to slightly below in E. Feb: mostly below normal precip.
USA - NCEP CFS2 MONTHLY
Temp: Dec: A little above normal, normal for N Ireland, NE England and N Scotland. Jan: Normal. Feb: Normal.
PPN : Dec: N Scotland below, N Ireland NE England and parts of SW normal - elsewhere above. Jan: Mostly normal, parts of SW and SE England and W Scotland above. Feb: mostly normal, N half Scotland below normal.

USA - IRI
Temp: 40% prob for temperatures above normal, 33% in N Ireland. (Jan Feb Mar shows reduction in probs so may be a cooling trend)
PPN : No sig variation from normal climate probs diagnosed.

USA - ECPC (UCSD) GSM COAPS
Temp: Dec: N normal, S below normal (0.5 to 1 C). Jan: Below normal in N, normal elsewhere. Feb: Above normal, less marked in S and SE.
PPN : Dec: Western areas slightly below normal, normal elsewhere. Jan: Near normal but N Ireland and Scotland above normal. Feb: Normal generally but below in parts of SW.

USA - FSU COAPS GSM
Temp: Above normal but less so across England.
PPN : Above normal in N and in far S, otherwise slightly below normal.


Source USA - NMME National ensemble of seasonal forecasts
Temp: Oct: near normal but above in far SE and far NW of UK. Nov: no departure from normal. Dec: no departure from normal. Jan: Mostly above normal. Feb: no departure from normal.
PPN : Oct: NW Scotland slightly below, otherwise near normal. Nov: near normal. Dec: NW Scotland slightly below, otherwise near normal.Jan: near normal. Feb: NW Scotland slightly below, otherwise near normal.

Source USA - IMME International ensemble of seasonal forecasts
Temp: Oct: mostly above normal Nov: mostly above normal Dec: SE above remainder near normal Jan: Slightly above normal Feb: S/SE above normal, normal elsewhere.
PPN : Oct to Jan: no indicated departures from normal. Feb: Nearby France hint of above normal hence risk for SE. Mostly normal.



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