SUMMARY OF SEASONAL FORECAST DATA FOR UK AND EIRE


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Experimental summary of Climate Forecasts for the UK for this and next month - updated as new data becomes available.
Previous issue November 2017 data
Seasonal - latest issue


Summary of internationally available experimental Forecasts for current month and next month for the UK and Eire
Updated 281217. (Typically updated during Thursday/Friday). Major updates may be noted on Twitter @T2mike








Met Office regular update text for 30days


Interpreted from UKMO.
UKMO 281217 - 1st to 25th January 2018: Unsettled periods with wind/gales and rain spreading from west, showery spells in between. Snow mainly for the North. Trending less unsettled in S/SE. Frost developing in any quieter overnight spells. Temperatures near normal, to cold in the north but trending near normal, to mild in the south.
UKMO 211217 - 26th December 2017 to 19th January 2018 Unsettled period with wind and rain but also hill snow in the N. Chance of some drier intervals and possibly some overnight frost in any drier intervals between weather systems. Trending drier in the south later in the period but with assoicated fog and frost risk.
UKMO 141217 - 11th December 2017 to 4th January 2018 Milder period, unsettled and windy at times in the N but less unsetled in the S. Snow confined to mountains in Scotland. Late in December and into January turning colder with short unsettled periods but a trend to drier weather in the S. UKMO 061217 - 11th December 2017 to 4th January 2018. Cold with wintry precipitation in many places especially areas exposed to showery N or NW winds - typically N and parts of W UK. Some briefly milder intervals, cheifly in the S/SW, with rain replacing snow risk temporarily but elsewhere snow risk continues as Atlantic weather systems move east over the Uk.br> UKMO 301117 - 5th December to 29th December 2017. Indeterminate mix of colder types (with wintery precip especially in the north) and milder westerly types bringing cloud and rain (especially for the S and W). Some drier spells in between. Overall N likely to be colder than normal and the S near normal but colder/milder at times.


CFS2 Anomalies are with respect to 1999-2010 hindcast climatology

CFS2 Data 271217
28-3J TEMP: S UK above elsewhere normal PPN: above normal but Scotland may be bormal or below
4J-10 TEMP: S UK above elsewhere normal but Eire may be below PPN: mostly above normal
11-17 TEMP: above normal PPN: above normal
18-24 TEMP: above normal PPN: S normal elsewhere above normal

CFS2 Data 201217
21-27 TEMP: above normal PPN: S Normal or below elsewhere above
28-3J TEMP: above normal but far N normal PPN: above normal
4J-10 TEMP: Eire and N UK normal or below elsewhere above PPN: above normal
11-17 TEMP: above normal but N and Eire normal PPN: above normal but S may be normal

CFS2 Data 131217
14-20 TEMP: N may start below otherwise above normal PPN: normal locally above in N/NW
21-27 TEMP: above normal PPN: normal locally above in N perhaps below in S elsewhere normal
28-3J TEMP: mostly above normal PPN: above normal
4J-10 TEMP: mostly above normal PPN: above normal

CFS2 Data 051217
6D-12 TEMP: below normal PPN: Above normal in N Scotland elsewhere normal locally below in S UK.
13-19 TEMP: below normal PPN: normal
20-26 TEMP: above normal locally normal in Eire. PPN: normal
27-2J TEMP: above normal PPN: normal locally above in S and W

CFS2 Data 291217
30-6D TEMP: Below normal but far N Scotland above PPN: Below normal
7D-13 TEMP: Above normal or normal PPN: Below normal
14-20 TEMP: Below normal but normal in N PPN: normal or above espeically in S/SW
21-27 TEMP: Above normal PPN: normal or above espeically in S/SW




JMA - issued - 271217
28day mean - Temp above normal PPN above normal PMSL below normal in N above in S (gale WSW) .
30-5J TEMP: above normal PPN: above normal PMSL: well below normal especially in N (Gale W) .
6J-12 TEMP: above normal PPN: above normal PMSL: below normal (gale WSW).
13-26 TEMP: above normal PPN: above normal PMSL: abive normal but N below (Gale WSW).

JMA - issued - 201217
28day mean - Temp above normal PPN above normal PMSL below normal (gale WSW) .
23-29 TEMP: above normal PPN: above normal PMSL: strongly below normal (gale W) .
30-5J TEMP: above normal PPN: above normal PMSL: strongly below normal (strong W) .
6J-19 TEMP: above normal PPN: S/SE below normal elsewhere above normal PMSL: N below S above (strong WSW) .

JMA - issued - 131217
28day mean - Temp above normal PPN above normal PMSL above normal in S below in N (Very strong WSW).
16-22 TEMP: above normal PPN: above normal in far N but mostly below normal PMSL: well above normal (high just SW W, strong in N).
23-29 TEMP: above normal PPN: above normal PMSL: below normal in N normal or above in far S (Very strong W signal for gales) .
30-12 TEMP: above normal PPN: above normal PMSL: below normal (Very strong SW) .

JMA - issued - 071217
28day mean - Temp below normal except SW England above PPN above normal PMSL below normal (strong WNW).
9D-15 TEMP: below normal PPN: above normal PMSL: well below normal (strong NW).
16-22 TEMP: below normal except perhaps far SW PPN: above normal but N Scotland normal PMSL: belopw normal (W) .
23-5J TEMP: Above normal PPN: Above normal PMSL: below or in N well below normal (strong W).

JMA - issued - 291217
28day mean - Temp above normal PPN above normal PMSL above normal (W) .
2D-8D TEMP: above normal PPN: below normal PMSL: well above normal H close to W (N).
9D-15 TEMP: below normal PPN: above normal PMSL: above in N below in S (WNW).
16-29 TEMP: above normal PPN: above normal PMSL: beow normal (Strong WSW) .



CMA 100 member Ensemble issued date 261217
26-4J TEMP: Above normal but 40% below normal in the N/NW UK and Eire
PPN : above normal
5J-14 TEMP: above normal
PPN : mostly above normal but in S/SW UK and Eire 40% prob below normal
15-24 TEMP: above normal
PPN : N/NW 60% prob above S/SE (UK and Eire) 60% below normal
25-3F TEMP: above normal
PPN : above normal

CMA 100 member Ensemble issued date 211217
21-30 TEMP: above normal
PPN : above normal but far S England may be nearer normal or below
31-9J TEMP: above normal
PPN : slightly above normal but parts of Scotland may be below
10-19 TEMP: above normal
PPN : England and Wales 60% chance of below normal, Scotland 20% and Eire/N Ireland 40%
20-29 TEMP: above normal
PPN : above normal, slightly lower probs for above normal in England

CMA 100 member Ensemble issued date 161217
16-25 TEMP: 60% chance below normal
PPN : Parts of Scotland below elsewhere above
26-4J TEMP: near or slightly below normal
PPN : mostly above but far N Scotland mauy be below
5J-14 TEMP: near or slightly above normal
PPN : mostly above but Scotland 60% above / 40% chance below normal
15-24 TEMP: above normal
PPN : above normal

CMA 100 member Ensemble issued date 111217
11-20 TEMP: below normal
PPN : above normal but far N Scotland may be below
21-30 TEMP: 40% prob below 60% prob above
PPN : above normal
31-9J TEMP: 60% prob below 40% prob above
PPN : above normal but NE Scotland may be below
10-19 TEMP: above normal
PPN : above normal but S UK may be below

CMA 100 member Ensemble issued date 061217 (available 071217)
6D-15 TEMP: N Scotland below normal elserwhere above
PPN : above normal except perhaps SW England
16-25 TEMP: normal or above
PPN : slightly above normal
26-4J TEMP: normal or above
PPN : above normal but N may be normal
5J-14 TEMP: above normal
PPN : S Eire and SW England below elsewhere normal or above

CMA 100 member Ensemble issued date 011217 (available 071217)
1D-10 TEMP: Above normal but England and parts of Wales below
PPN : below normal
11-20 TEMP: Above normal
PPN : NE Scotland below normal elsewhere normal or above
21-30 TEMP: Above normal
PPN : Above normal
31-9J TEMP: Above normal

PPN : N Scotland normal or above elsewhere mostly below but parts of Wales normal or above




December single issue forecast

UKMO contingency 271217
TEMP:
December Slightly below normal. Clustering almost equal above and below normal so not definitely colder than average.
PPN:
December Large even spread, reaches outside range of 1981 to 2010 climatology, but slight clustering at below normal.



CanSIPS - 301117 DEC above normal
PPN :
DEC Scotland and SE England normal elsewhere below normal


Next full month January 2018 (number of runs) [running total]



NOAA - CFS2 281217 valid for January 2018
TEMP: above or well above normal [27/27]
PPN : above or well above normal. England and Wales above [27/27], Scotland and Ireland [21/27] but N Scotland [19/20]

NOAA - CFS2 211217 valid for January 2018
TEMP: Above normal 7/7 [20/20]
PPN : far N Scotland above normal 2/7 elsewhere above normal 7/7. England and Wales above [20/20], Scotland and Ireland [14/20] but N Scotland [12/20]

NOAA - CFS2 141217 valid for January 2018
TEMP: Above normal 7/7 [13/13]
PPN : Above normal England and Wales 7/7 [13/13] Scotland and Ireland 3/7 [7/13]

NOAA - CFS2 061217 valid for January 2018
TEMP: Above normal 6/6
PPN : Above normal 6/6 but N Scotland 4/6



UKMO Contingency 181217
TEMP:
JAN: UKMO above more likely than below but allowing for a cold spell in month. Analysis: Large spread of solutions slightly shifted to above normal but with two small clusters one slightly below the other above normal but also signs of a chance of well above normal. Median value looks close to normal.
PPN:
UKMO "For January, and January-February-March as a whole, above-average precipitation is more likely than below-average precipitation. The likelihood of impacts from heavy rainfall and high winds is greater than usual".
JAN: Analysis: Although there are more solutions than usual in the much wetter than norml there is also an increase in numbers in the slgihtly below normal range. Two clusters the largest one shows slightly below normal and the other well above normal so it is not clear cut that January will be wetter for all of UK.


ECMWF - monthly - 141217 - data from Weather US
TEMP:
JAN S of England slightly above normal elsewhere normal (+/- 0.5F)
PPN:
JAN NW Scotland below elsewhere above, largest anomaly SW Wales
PMSL:
JAN below or well beloww normal especially near and WSW of UK/Eire



CanSIPS - 301117
TEMP:
JAN above normal
PPN :
JAN N Scotland normal elsewhere above normal





CFS2 E3 ensemble of 10 days of model runs. Updated - see date on graphic.
TN1 TN4


Graphics ex NOAA CPC
NMME T2M and PPN anomaly UK ZOOMED area plotted from 1 DEG GRIB NMME data

NMME NMME

CFS2 MAX and MIN

CFS CFS

CFS2 PPN rate and 2M temp anomaly
CFS CFS

NMME MAX and MIN not available

NMME T2M and PPN anomaly

NMME NMME

Temp and PPN rate probability NMME

NMME NMME


NOTEs: 1. NORMAL=typically the model normal based on historic runs rather than the measured normal from observation - hence trends rather than numbers are a better guide.
2. CFS2 seasonal anomalies are with respect to the lead dependent model climatology from the hindcast period (1999-2010) without any adjustment - a very warm decade!.
3. UKMET The hindcast period used for model normal is 1996 to 2009. 42-member ensemble seasonal forecast (120KM res over land) combining and bias correcting all forecast members available prior to issue.
4. CFS2 Weekly forecast anomalies are with respect to 1999-2010 hindcast climatology which was a warm period (SST 1982-2010) also mostly a wet period for Uk compared to longer period stats.
CFS2 Monthly and seasonal hind cast period 1982-2010
5. NMME data, please see the BAMS article (Kirtman et al. 2014). The NMME project and data dissemination is supported by NOAA, NSF, NASA and DOE. with the help of NCEP, IRI and NCAR personnel in creating, updating and maintaining the NMME archive.

KEY:
UKMO=UK Met Office KMA= Korea Met Agency JMA=Japan Met Agency Russia=Hydrometcentre of Russia NOAA=main US climate data model used by Climate Prediction Centre. Other N America data also used via NASA and IRI. CMA=China Meteorological Administration

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