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Old September 8th 09, 05:08 PM posted to uk.sci.weather
Philip Eden Philip Eden is offline
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First recorded activity by Weather-Banter: Jul 2003
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Default Summer quarter 2009: Synoptic Overview

"Philip Eden" philipATweatherHYPHENukDOTcom wrote :

The present exceptionally weak phase of the Arctic
Oscillation appears to have been the dominant influence
on the synoptic characteristics of the summer quarter
(J,J,A) of 2009.

Mean sea-level pressure and anomaly charts can be found at

http://www.climate-uk.com/monpre/09QQ.htm

The mean sea-level pressure field shows the Icelandic
Low displaced well south of its normal location at
56N 20W, central pressure 1009mbar. The Azores
High is at normal intensity (1022mbar) slightly SW of
its normal position. The net effect is to transfer and squeeze
the strongest surface flow across the Atlantic to between
latitudes 40 and 50degN instead of its normal position
between lats 45 and 60degN. There is an anomalous
area of high pressure, 1020mbar, centred over Greenland.
The mean surface flow over the British Isles is SW-ly
instead of the more usual W-ly.

The mean anomaly field is dominated by two centres:
-7mbar off SW Ireland (at 51N 19W)
+8mbar over central/NE Greenland
The anomalous flow over the British Isles is SSW-ly over
England, Wales and Ireland, and SSE-ly over Scotland.
Mean anomaly ranges from -1.5mbar in Sussex and Kent
to -5mbar on the west coast of Ireland. The 'southerliness'
index has only been exceeded in four summers in 137
years of records: in 1947, 1950, 1994 and 2003.

CET (Manley): 15.93°C (+0.3 degC wrt 1971-2000)
E&W Rainfall: 252.3mm (128% wrt 1971-2000)
E&W Sunshine: 589.0h (100% wrt 1971-2000)

CScotT: 14.76°C (+0.7 degC)
Scot Rainfall: 300.2mm (150%)
Scot Sunshine: 542.6h (114%)

NIT: 14.78°C (+0.5 degC)
NI Rainfall: 307.8mm (161%)
NI Sunshine: 567.1h (117%)

(c) Philip Eden

I've not finalised my data for the summer quarter (JJA).

Highest mean maxes we
23.5 Canterbury
23.1 Heathrow
22.9 Cambridge
22.9 Broadness (Kent)
22.8 St James's Park
(also 23.0 Clerkenwell [rooftop site])

Lowest mean maxes (excluding sites above 300m amsl) we
14.4 Fair Isle
14.8 Lerwick (Shetland)
15.3 Baltasound (Shetland)
15.7 Wick (Caithness)


Biggest +ive anomalies were +2.3degC at Marham
(Norfolk) and Charlwood (Surrey)
Biggest -ive anomalies were -0.8degC at Aberdaron
(Caernarfon) and -0.7degC at L.Vyrnwy (Montgomery)
[some of these anomalies appear to be outliers, suggesting
a change of site which I'm not aware of, or an error in
calculation of averages]

Highest mean mins we
14.5 at St Cath's Point (IoW)
14.2 at Lee-on-Solent (Hants)
14.2 at Eastbourne
14.1 at Portland (Dorset)
(also 14.8 on that roof at Clerkenwell)

Lowest mean mins (excluding sites above 300m amsl) we
8.0 at Braemar (Aberdeenshire)
8.4 at Loch Glascarnoch (Wester Ross)
8.6 at Dalwhinnie (Inverness-shire)
8.7 at Kinbrace and Altnaharra (both Sutherland)

Biggest mean min anomalies we
+2.4degC at Pembrey Sands (Carmarthen)
+2.2degC at St Angelo (Co Fermanagh)
-1.0degC at Topcliffe (N Yorks)
-1.0degC at Glenanne (Co Armagh)
[ditto comments above]

Highest rainfall:
706.0mm at Inveruglas (Dunbartonshire)
696.5mm at Eskdalemuir (Dumfriesshire)
661.7mm at Capel Curig (Snowdonia)
637.0mm at Shap (Cumbria)
622.6mm at Valentia (Irish Rep)
588.3mm at Tyndrum (old Perthshire)
574.6mm at Cluanie Lodge (Wester Ross)
560.7mm at Liscombe (Exmoor)

Highest rainfall percentages wrt 1971-2000:
299 St Mary's (Isles of Scilly)
296 Valentia
251 Eskdalemuir
233 Cork
212 Bishopton (Renfrewshire)

Lowest rainfall:
84.7mm at Canterbury
91.9mm at Shoeburyness (Essex)
96.6mm at Brooms Barn (Suffolk)
100.9mm at East Malling (Kent)
102.7mm at Andrewsfield (Essex)

Lowest rainfall percentages:
78 at Andrewsfield
79 at Odiham (Hants)
79 Middle Wallop (Hants)
80 at Shoeburyness

Highest sunshine totals:
770.4h at Eastbourne
750.8h at Manston (Kent)
699.6h at St Helier (Jersey)
676.8h at St Peter Port (Guernsey)
649.6h at Weymouth

Highest sunshine percentages:
143 Fair Isle
127 Malin Head (Irish Rep)
122 Tiree
118 Lerwick
118 Manston

Lowest sunshine totals:
333.4h at Eskdalemuir
344.4h at Kinlochewe (Wester Ross)
393.6h at Durham
406.6h at Braemar
412.1h at Dyce (Aberdeen)
419.0h at Woodford (Gtr Manchester)

Lowest sunshine percentages:
74 at Eskdalemuir
78 at St Athan (Glamorgan)
81 at Yeovilton (Somerset)
82 at Watnall (Notts)
82 at Woodford
83 at Shawbury (Salop)

(c) Philip Eden