Llansadwrn (Anglesey) Weather Observations from the observer's spreadsheet SEPTEMBER 2013

Graphics

Key to observations.

CLIMATOLOGICAL OBSERVATIONS AT LLANSADWRN, ANGLESEY, FOR SEPTEMBER 2013
	<----09 GMT--->					<------------Air temperature-------->							<---Soil temp--->			<---Earth temp--->			<--State Grd.-->				Rain	Sol	<--Weather---->						Press	Pptn	Fr.	Pch
DD	N	dd	ff	V	ww	Temp	Dpt	RH	Max	Min	Mean	Gmin	5cm	10cm	20cm	30cm	50cm	100cm	E	C	Gr	SS	mm	MJ/m2	S	L	H	T	G	F	mb	W hrs	hrs	evap
1	8	W	3	7	02	13.6	10.7	83	14.7	9.6	12.2	5.0	15.4	15.2	16.2	16.7	16.9	16.2	0	0	1	0	tr	8.95							1030	0	0.0	1.6
2	8	SW	3	5	50	14.5	13.7	95	19.1	12.3	15.7	7.5	15.1	15.2	16.0	16.4	16.6	16.2	0	0	3	0	tr	8.30							1028	0	0.0	1.1
3	8	SW	1	6	10	16.6	16.0	96	19.2	14.4	16.8	10.2	16.7	16.3	16.3	16.6	16.6	16.1	0	1	3	0	0.0	10.22							1027	1	0.0	1.1
4	6	SW	1	8	03	15.3	12.6	84	22.6	10.7	16.7	6.9	15.7	15.1	15.9	16.4	16.7	16.2	0	0	1	0	tr	13.40							1021	0	0.0	1.6
5	8	N	1	5	50	13.2	12.2	94	14.4	13.2	13.8	10.2	15.5	15.7	16.1	16.7	16.7	16.7	0	0	3	0	tr	4.57							1014	0	0.0	0.9
6	8	N	2	6	02	13.5	9.9	79	15.8	7.4	11.6	4.7	14.5	14.0	15.0	15.6	16.5	16.5	0	0	1	0	26.5	8.59							1011	16	0.0	0.9
7	7	SW	4	6	61	9.4	8.9	97	12.4	8.2	10.3	5.0	12.6	12.6	14.7	15.2	16.1	16.1	1	3	3	0	9.2	7.28							1010	13	0.0	0.7
8	5	S	4	7	01	10.0	9.4	96	15.0	8.2	11.6	5.5	12.4	12.2	14.4	14.7	15.6	15.8	1	2	3	0	2.3	9.95							1015	3	0.0	1.1
9	6	SW	1	7	01	13.3	11.4	88	16.6	8.6	12.6	5.3	14.2	13.2	14.6	15.1	15.5	15.7	1	0	1	0	0.0	12.51							1017	0	0.0	1.3
10	7	NE	4	6	05	12.8	10.5	86	15.5	10.8	13.2	7.2	13.1	13.3	14.8	15.2	15.4	15.6	1	0	1	0	0.0	6.47							1025	0	0.0	1.4
11	7	SW	3	7	02	12.6	11.0	90	14.9	11.6	13.3	10.3	14.1	13.8	14.9	15.1	15.3	15.8	1	0	1	0	6.2	3.37							1024	14	0.0	0.3
12	7	S	4	7	10	14.8	14.5	98	18.8	12.6	15.7	12.1	16.1	15.2	15.2	15.3	15.3	15.4	1	2	3	0	3.7	6.76							1020	7	0.0	0.4
13	7	N	2	7	10	11.5	10.9	96	13.8	11.0	12.4	8.8	15.1	14.8	15.2	15.8	15.6	15.3	1	1	1	0	2.2	5.05							1020	6	0.0	0.8
14	5	N	3	7	01	11.3	9.4	88	15.3	7.4	11.4	4.3	13.2	13.2	14.8	15.1	15.4	15.2	1	1	1	0	0.4	11.89							1019	2	0.0	1.9
15	8	S	7	5	02	12.7	11.7	94	15.3	7.8	11.6	3.4	12.8	12.8	14.2	14.7	15.1	15.2	1	3	3	0	6.7	2.89			4				1004	5	0.0	1.3
16	3	SW	4	7	01	9.7	6.6	81	12.8	7.8	10.3	4.7	11.0	11.2	13.8	14.2	15.1	15.2	1	0	1	0	1.0	6.77							1002	2	0.0	1.4
17	8	SW	3	5	03	9.6	6.8	83	11.6	8.8	10.2	5.9	11.1	11.4	13.6	14.0	14.9	15.1	1	3	3	0	7.9	4.19							1000	10	0.0	0.2
18	7	SW	2	7	03	10.1	9.5	96	14.6	7.8	11.2	4.9	12.1	11.8	13.5	13.8	14.8	15.0	1	2	1	0	6.3	8.35							1005	4	0.0	1.3
19	8	S	7	6	61	12.2	11.7	97	17.4	8.0	12.7	3.9	11.9	11.9	13.4	13.9	14.8	14.9	1	3	3	0	1.4	9.17							1004	0	0.0	1.2
20	6	SW	1	7	02	12.4	9.9	85	15.3	10.3	12.8	7.6	14.1	13.5	14.1	14.3	14.7	14.8	1	0	1	0	0.2	7.34							1019	1	0.0	1.7
21	8	S	2	6	50	15.2	14.4	95	19.3	10.9	15.1	7.5	14.5	13.8	14.2	14.4	14.8	14.8	1	3	3	0	tr	10.32							1021	0	0.0	1.4
22	2	SW	4	7	02	16.7	14.5	87	19.7	14.3	17.0	10.4	14.9	14.8	15.0	14.9	14.8	14.7	1	0	1	0	0.0	9.46							1028	0	0.0	1.5
23	8	S	1	7	02	15.1	14.4	96	16.8	13.0	14.9	8.4	15.9	15.6	15.4	15.3	15.2	14.9	1	0	1	0	0.0	4.48							1025	1	0.0	0.5
24	4	N	1	4	10	15.0	14.7	98	18.1	11.1	14.6	6.7	13.4	13.3	14.9	15.2	15.2	14.9	1	2	2	0	3.8	6.96						2	1016	4	0.0	0.4
25	7	N	1	5	60	14.3	14.0	98	15.3	12.8	14.1	11.1	14.8	14.8	15.3	15.4	15.3	14.9	1	2	3	0	tr	3.34						3	1012	0	0.0	0.4
26	8	00	0	6	02	14.4	12.6	89	18.1	13.6	15.9	11.6	15.0	14.8	15.3	15.3	15.2	14.9	1	0	1	0	0.7	4.96							1016	3	0.0	0.9
27	2	N	1	7	10	15.1	14.3	95	22.0	11.7	16.9	7.4	14.4	14.4	15.3	15.4	15.3	15.0	1	1	1	0	0.0	11.05							1015	0	0.0	2.0
28	3	N	1	8	01	14.4	10.7	78	18.6	11.8	15.2	7.5	13.9	14.2	15.4	15.6	15.6	15.0	1	0	1	0	1.6	5.88							1009	3	0.0	2.3
29	4	E	3	7	01	14.7	10.7	77	17.2	12.1	14.7	9.6	14.1	14.1	15.2	15.4	15.3	15.0	1	0	1	0	0.0	10.43							1008	0	0.0	2.1
30	7	SE	4	6	02	14.6	12.8	89	16.8	11.2	14.0	5.6	13.7	13.6	14.9	15.1	15.3	15.0	1	0	1	0	0.6	2.69							1006	2	0.0	1.1
N	79	%
Means---->						13.3	11.7	90	16.6	10.6	13.6	7.3	14.0	13.9	14.9	15.2	15.5	15.4						7.52							1016
Totals----->																							80.7	225.61	0	0	1	0	0	2		97.0	0.0	34.8
MEANS AND AVERAGES AT LLANSADWRN, ANGLESEY FOR SEPTEMBER 2013
Differences from 2003-2012 average* as used by the Weather Observers Network & from 1981-2010 average**.
Air temperature (C)							*	**		Weather (No. days occurrence)						*		Wind direction (days)								Rainfall (mm)						*	**
	Mean maximum					16.6	-0.7	-0.7			Sleet/ snow falling				0	0.0			N			8					Total				80.7	66	84	%
	Mean minimum					10.6	-0.4	0.3			Snow lying (at 09 GMT)				0	0.0			NE			1					Largest fall				26.5
~	Mean (max+min)/2					13.6	-0.5	-0.2			Hail <5 mm				1	0.1			E			1
	Highest maximum					22.6	-0.4				Hail >=5 mm				0	{All types}			SE			1				Evaporation (mm)
	Lowest maximum					11.6	-1.2				Thunder heard				0	-0.3			S			6					Lysimeter				PE	27.2
	Highest minimum					14.4	-0.7				Gales				0	n.a.			SW			11					Monthly total				PWB	53.5
	Lowest minimum					7.4	0.7				Fog (at 09 GMT)				0	n.a.			W			1									PWS	68.6
	No. days <0.0C					0	0.0			Rainfall (No. days occurrence)									NW			0									PWD	-15.0
Grass minimum mean						7.3	-1.3				No pptn		0.0 mm		7	-1.0			Calm			1					AWS				ET	35.4
Lowest minimum						3.4	0.6				Dry		< 0.2 mm		13	5											Piche				P I	34.8
	No. days <0.0C					0	0.0				Rain		>= 0.2 mm		17	-0.6			Check days			30
Earth temperature 30cm						15.2	0.4				Wet		>= 1.0 mm		13	0.1			This month			30
													>= 5.0 mm		6	-1.3

Note: Unusual peaks seen on the PE graph are due to recent rainfalls or unmelted snow having not yet percolated through the soil. This method is not good for daily measurements, but good results are obtained over 3 days (allowing time for percolation) and on a monthly basis. The lysimeter also measures dew and depositions of frost, and is a better raingauge than one with a rim at 30 cm high. In winter, when evaporation from the ground is low, negative values are sometimes seen and indicate an accumulation of dew and frost, and more rain than measured by a standard raingauge. In summer, when evaporation is high and rainfall less, the lysimeter still measures dew and more rain than the standard gauge, but the effect is less noticeable. The daily graph is show here for it's interest and you can read more about this 'classic' method of measuring evaporation here

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  DD date; N cloud (oktas, 9=obscured); DD wind direction (8 sectors, 00=calm); ff wind speed (Beaufort scale);
  V visibility (0 dense fog, 1 thick fog, 2 fog, 3 moderate fog, 4 very poor, 5 poor, 6 moderate, 7 good, 8 very good);
  WW present weather SYNOP code (eg. 01 cloud decreasing, 02 sky not changing, 03 cloud increasing, 04 smoke haze, 05 haze)
  Temperatures (degC); Temp dry bulb temperature; Dpt dewpoint; RH relative humidity (%); soil temperatures are under bare
  soil and earth under grass; SS snow depth (cm); Press air pressure, aneroid (mb). For state of the ground E, concrete C,
  and grass Gr codes consult the page on 'Recording Atmospheric Depositions on Grass'. 

24 hour observations...

  Max maximum temperature (degC) beginning 09GMT; Min minimum temperature ending 09GMT;
  Gmin grass minimum temperature (degC) ending 09GMT; Pch Evap Piche evaporation (ml) beginning 09GMT;
  Rain rainfall beginning 09GMT (mm); Pptn  W hrs number of hours with precipitation 09-09GMT; trace <0.05 mm; tr trace of rain; tr dw trace of dew;
  tr fr trace of frost; Fr. hrs hours of frost (09-09GMT).
  Sol MJ/m2 Global Solar Radiation (MJ per m2) 00-00 GMT. 

Monthly observations...

  PE Potential evapotranspiration, PWB Potential water balance, PWS Potential water surplus, PWD Potential water deficit.

Weather: days with...

  s slight or S heavy snow/sleet falling; L >=50% snow cover at 09GMT; H categories of hail: 1 ice crystals, 2 snow grains,
  3 snow pellets, 4 ice pellets, 5 hail 5-9 mm, 6 hail 10-19 mm; up unidentified precipitation;
  t slight or T heavy thunder heard; G gale; Fog any hour 1, 09 GMT 9. Gales (Beaufort land scale) refer to the area.

These pages are designed and written by Donald Perkins © 2013 http://www.llansadwrn-wx.co.uk