Monthly Weather No. 305 Bulletin September 2011

An onlooker enjoys a beautiful mixture of stratocumulus and cirrus clouds during a sunrise in late September at Bettystown Beach, Co. Meath (picture courtesy Donal Black) MOST PLACES WARM AND WET; DULL EVERYWHERE Rainfall in September was above average almost recorded at Carlow (Oak Park) on this date. Mean everywhere, with the west and midland areas air temperatures for the month were above normal receiving the highest percentages above normal for almost everywhere, with most stations reporting the time of year. The highest rainfall total at a differences of nearly 1°C or more above the normal synoptic station was recorded at Valentia and most stations in the east and north of the Observatory, recording its wettest September since country reported it was the warmest September 2005, receiving 162% of its long-term average.The since 2006. The majority of the highest maximum majority of the month’s highest daily falls were air temperatures for the month were reported on recorded on the 30th, with the highest September the 28th, with Phoenix Park recording a maximum daily fall (midnight to midnight) of 46.5mm air temperature of 25.7°C on this date. This was

Produced by Met Éireann, Glasnevin Hill, Dublin 9. INSIDE Diary ...... 8 Annual subscription 80 euro Rainfall ...... 10 Hurricane Katia- Temperature ...... 12 Page 3 For more information- Sunshine ...... 14 tel: +353-1-8064260 Marine & Pressure .... 1 5 fax: +353-1-8064216 [email protected] Wind & Elements ...... 4 World Weather ...... 16 www.met.ie/climate Upper Atmosphere...... 5 Notes on the tables and map Laboratory ...... 6 showing location of stations Agmet...... 6/7 appear in January issue Edition 305.1 2 WEATHER September 2011

Above: Astronauts on the the highest maximum air temperature at the end of the period. International Space station recorded at a synoptic station so far in captured this image of Aurora 8th to 13th: A mild and cloudy start was 2011 and the highest September followed by slightly cooler weather with Australis or the southern temperature recorded at the site since outbreaks of drizzle, light to heavy rain and lights on September 17th. 1906 (105 years). Mean minimum air scattered showers. A very deep depression, Auroras are caused by the temperatures were also above average for resulting from ex-hurricane Katia moved interaction between high the time of year, with Valentia across the northeast Atlantic between Ireland energy particles from the Observatory and Casement Aerodrome and Iceland, bringing extremely strong winds solar wind and the earth’s with gales recorded in coastal areas and gale magnetic field. The colours of reporting their warmest minimum air gusts recorded in most locations. an Aurora are caused by the temperatures in September since 1955 particles colliding with (56 years) and 1964 (47 years) respectively. 14th to 25th: A weakening depression moved Sunshine values were below average in from the west, bringing drier conditions oxygen and nitrogen with cloud and showers (some with thunder), molecules in the atmosphere everywhere for September, with the followed by a series of deep depressions off (picture courtesy NASA Earth highest amounts of sunshine in the east. the northwest coast which affected the Observatory) Stations in the south and southwest were country. Associated frontal systems brought the dullest, with Valentia Observatory and bands of rain and heavy showers with some Cork Airport recording their lowest clear sunny spells to parts. Winds were light to moderate at the start of the period, September sunshine since records began becoming strong in the latter half, with gale in 1893 (118 years) and 1962 (49 years) gusts recorded in most areas. respectively. Shannon Airport also reported its dullest September since 1956 26th to 30th: A high pressure system located (55 years). Mean wind speeds for the over the continent brought warmer temperatures and dry weather to most areas month were above normal for September, at the start of the period. A cold front then with gales reported on three days. passed over Ireland, with heavy consistent Belmullet reported a mean wind speed of rain and showers. Winds were predominantly 15.2 knots (28km/h), its highest mean light to moderate, south to southwesterly in wind speed for September since 1980 direction, gale gusts along western coasts. (55 years), while Shannon Airport Wind and elements: Mean windspeeds for reported a monthly mean wind speed of the month of between 8 and 18 knots (15 and 12.2 knots (23km/h), its highest since 1970 33km/h) were above normal. Gale gusts were (41 years). recorded on most days, except from the 1st to the 3rd, 8th, 15th and 26th, with gales 1st to 7th: After a brief, warm dry start to the reported on the 10th, 12th and 21st. The month, Atlantic depressions near or over month’s highest gust of 66 knots (122km/h) Ireland and their associated frontal systems was observed at Malin Head on the 12th. resulted in mixed periods of drizzle, rain and Thunderstorms were recorded on the 4th, thundery showers, with some clear dry spells 16th, 17th, 21st and 30th, with one report of in parts. Winds varied from light to strong, hail on the 17th. Fog was reported mostly in predominantly southerly to westerly in the west and along southern coasts at the direction, with numerous gale gusts as a beginning and end of the month. deepening depression moved in over Ireland September 2011 WEATHER 3 HURRICANE KATIA and continued travelling northwest over the Atlantic Ocean, before being downgraded to a Category 1 hurricane again on the 7th. Hurricane Katia continued to move northwest, until September 8th, when its trajectory moved north then northeast towards northern Europe. On the 10th, Katia continued to move towards Ireland and the UK, however, it was gradually losing its tropical characteristics and by 1500 UTC on the 10th, Hurricane Katia was downgraded to a post-tropical storm. The deep area of low pressure which contained The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-colour image at 15:15 UTC on September 7th. Katia sports the Post-Tropical Storm Katia, reached Irish waters spiral shape and eye typical of strong storms (picture courtesy of NASA Earth Observatory) on early Monday the 12th of September and September is the peak of the Atlantic was located 300km northwest of Erris Head, Hurricane season and during September 2011, Co. Mayo. It continued to move northeastward NASA satellites were keeping tabs on a number over Northern Scotland during the day, with of tropical storm systems. Hurricane Katia, the areas in Scotland and Northern Ireland worst second major hurricane of the 2011 Atlantic hurricane season, affected Northern Europe during mid-September. Hurricane Katia, who remained over the open waters of the Atlantic throughout its life cycle, formed in late August and during the first few days of September, crossed the Atlantic, reaching Irish waters and the UK as a post-tropical storm on the 12th. Katia initially formed as a tropical depression, south of Cape Verde (an island located in the central Atlantic Ocean) on August 29th 2011. By September 2nd 2011, the storm had moved northwest across the Atlantic Ocean and Pressure analysis chart for Monday 12th of September 0600 UTC, shows the low pressure system that contained Post-Tropical Storm Katia off the northwest coast of strengthened to a Category 1 hurricane, with Ireland (chart courtesy of Met Office UK) windspeeds of 65 knots (120km/h) and even higher gusts. On September 4th, Katia had affected, causing storm to gale force winds in strengthened to a Category 2 hurricane, with parts. The highest gust recorded in the UK was reported windspeeds of 86 knots (160km/h) 85 knots (157 km/h) at Cairngorm Summit in Scotland while Malin Head, Co.Donegal recorded the highest gust in the Republic of Ireland of 66 knots (122km/h) and a mean 10- minute windspeed of 48 knots (89km/h).

Damage that Katia caused reached as far as Russia, with numerous homes across Ireland and the UK being left without power. The damage is estimated to have reached over one hundred million pounds in the UK, with three deaths across the globe attributed to its effects.

Potential Track area for Post-Tropical Storm Katia issued at 1500 UTC on Information supplied by September 10th. The current location of the post tropical storm was U.S National Hurricane Center (www.nhc.noaa.gov/) marked by the orange circle (picture courtesy of NOAA) NOAA National Weather Service (http://weather.gov/) 4 WIND & ELEMENTS September 2011

WIND (KNOTS) ELEMENTS County / Station Mean Max. 10-min. mean Max. Gust Days with Hours with speed dir. speed date/hour dir. speed date/time gales gale gusts gale gusts Snow Snow Lying Hail Thunder Fog CO. CARLOW Oak Park 9.9 250° 31 12/11 240° 45 12/1008 0 4 14 CO. CAVAN Ballyhaise 8.4 230° 26 12/09 220° 45 12/0901 0 3 17 CO. CLARE Shannon Airport 12.2 240° 36 12/07 240° 55 12/0631 1 8 46 0 0 0 0 0 CO. CORK Roche’s Point 13.8 220° 37 12/00 210° 47 12/0 31 1 8 42 Cork Airport 11.1 210° 32 11/24 230° 46 12/0238 0 6 30 0 0 0 0 10 CO. DONEGAL Malin Head 17.5 240° 48 12/11 240° 66 12/1105 3 15 139 0 0 0 0 0 CO. DUBLIN Dublin Airport 12.9 250° 39 12/12 250° 56 12/1009 1 8 60 0 0 0 1 0 Casement 12.6 230° 35 12/09 240° 50 12/1058 1 9 67 0 0 1 0 0 CO. KERRY Valentia Observatory 12.5 240° 31 12/03 220° 46 12/0 18 0 10 62 0 0 0 0 0 CO. MAYO Belmullet 15.2 220° 39 12/06 220° 61 12/0524 3 17 167 0 0 0 0 0 Knock Airport 12.3 240° 39 12/09 240° 59 12/0819 1 9 62 0 0 0 0 5 CO. TIPPERARY Gurteen 11.0 250° 30 12/11 250° 49 12/0954 0 3 18 CO. WESTMEATH Mullingar 7.8 220° 22 12/04 250° 41 12/1114 0 1 9 CO. WEXFORD Johnstown Castle 8.3 240° 22 12/04 210° 36 12/0105 0 1 7

Carlow (Oak Park) Belmullet

< 5

5 - 10

10 - 20

20 - 35

> 35 windspeed in knots

PERCENTAGE FREQUENCY OF WIND DIRECTION September 2011 UPPER ATMOSPHERE 5 Upper Atmosphere wind and temperature readings are made at Valentia Observatory 4 times daily by a radiosonde (a balloon with instruments attached). Shown below are daily average windspeeds and temperatures at defined pressure levels, 850, 700, 500 and 300hPa, corresponding approximately to heights of 1500, 3000, 6000 and 10000 metres. Monthly windroses are also shown for each pressure level. Upper Air Wind Speed and Temperature September 2011 300 hPa 300 hPa

500 hPa 500 hPa

700 hPa 700 hPa

850 hPa 850 hPa 6 LABORATORY September 2011

Chemical Analysis of Precipitation and Air Samples Acid rain occurs when at Valentia Observatory pollutants combine with moisture in the air to form pH and electrical conductivity are sulphuric or nitric acid. pH is not available on dry days (<0.2mm) the simplest way of measuring the acidity of precipitation. Usually pH of 7.00 is considered neutral but this is not the case in rainfall samples. Pure water in the atmosphere has an equilibrium pH value of 5.65 at 20°C owing to carbon dioxide in the air dissolving to form carbonic acid. Any value below pH 5.65 is considered acid while any data shown here are interim values and are subject to change value above is considered alkaline. Sulphur dioxide and sulphate in air contribute to the formation of sulphuric acid; nitrate in air contributes to the formation of nitric acid. Conductivity measures the total ion activity in the rainfall, i.e. the higher the conductivity the greater the number of ions present.

12.6 Soil Temperatures at 0900UTC Mean 100mm (+0.7) Soil Temperatures (°C) County/ °C at 0900UTC Station 100mm 200mm 300mm (difference from 1961-90 normals CO. CARLOW in brackets) 13.9 CARLOW (OAK PARK) 13.0 13.3 13.5 13.3 CO. CAVAN (+1.0) BALLYHAISE 13.3 13.8 14.1 11.5 CO. CLARE 13.4 SHANNON AIRPORT 13.3 13.5 14.6 CARRON 13.9 14.4 (+1.4) CO. CORK 12.4 12.8 ROCHE’S POINT 13.3 13.7 13.9 (+0.2) FERMOY (MOOREPARK) 13.4 13.6 14.3 13.0 CORK AIRPORT 12.4 12.8 13.7 13.3 SHERKIN ISLAND 13.7 14.1 14.4 (0.0) (+0.3) BALLINCURRIG (PEAFIELD) 12.6 12.4 13.5 CO. DONEGAL 13.9 MALIN HEAD 12.6 13.1 13.4 13.9 (+0.8) CO. DUBLIN (+0.6) 12.4 DUBLIN (PHOENIX PARK) 13.4 14.1 14.6 (-0.3) DUBLIN AIRPORT 12.6 12.9 13.6 CASEMENT AERODROME 12.4 12.9 13.7 2.3/ CO. KERRY 0 VALENTIA OBSERVATORY 13.9 14.4 15.4 CO. LIMERICK MOUNT RUSSELL 12.6 13.3 CO. MAYO BELMULLET 13.9 14.6 15.4 -10/-5 STRAIDE 13.6 2/-4 KNOCK AIRPORT 11.5 12.0 12.5 CO. MEATH -10/-10 WARRENSTOWN 13.4 14.1 15.0 1/-10 CO. TIPPERARY GURTEEN 12.8 13.0 13.3 15/-5 FETHARD (PARSONSHILL) 12.4 13.2 2/-2 CO. WATERFORD DUNGARVAN (CARRIGLEA) 14.0 14.4 2/-4 34/-10 CO. WESTMEATH MULLINGAR 13.4 14.0 14.7 Soil Moisture Deficits (mm) CO. WEXFORD n/a 10th of month / end of month JOHNSTOWN CASTLE 13.9 13.9 14.2 1/-10 JOHN F. KENNEDY PARK 14.3 14.7 15.5 -1/ (0 represents field capacity, CLONROCHE (KNOXTOWN) 14.0 14.6 14.5 -10 -10 saturation) CO. WICKLOW ASHFORD (CRONYKEERY) 14.4 14.6 14.7 September 2011 AGMET 7

10-DAY VALUES FOR SELECTED RAINFALL TEMPERATURE (°C) SUNSHINE AGROMETEOROLOGICAL (MM) (HOURS) STATIONS

Station period amount % of average rain days wet days mean max. mean min. mean daily from average diff. lowest min. date days with air frost degree days > 4.4°C degree days > 10.0°C lowest "grass-min." date days with ground frost mean 10cm at 0900h mean 30cm at 0900h total no. of hours % of average

Co. Cork 1-10 42.6 - 10 6 17.2 10.8 14.0 - 6.8 4 0 96 42 6.1 4 0 13.3 13.9 17.3 - Ballincurrig 11-20 21.2 - 6 4 16.2 8.6 12.4 - 5.1 14 0 80 28 5.0 14 0 11.9 13.4 40.8 - 21-end 60.2 - 9 8 16.1 10.8 13.5 - 6.7 26 0 90 36 6.1 26 0 12.7 13.3 18.8 - month 124.0 - 25 18 16.5 10.1 13.3 - 5.1 14 0 266 106 5.0 14 0 12.6 13.5 76.9 -

Co. Donegal 1-10 81.9 - 10 9 16.3 10.3 13.3 - 3.4 5 0 90 36 0.4 5 0 - - - - Glenties 11-20 95.8 - 10 10 15.8 10.4 13.1 - 9.2 20 0 87 31 5.9 20 0 - - - - 21-end 36.7 - 9 8 17.4 11.6 14.5 - 7.4 26 0 101 46 3.5 26 0 - - - - month 214.4 148 29 27 16.5 10.8 13.7 1.2 3.4 5 0 277 113 0.4 5 0 - - - -

Co. Kerry 1-10 39.7 - 10 9 18.0 11.7 14.9 - 9.1 1 0 104 49 7.6 1 0 - - 23.6 - Ardfert 11-20 35.5 - 9 7 16.3 10.1 13.2 - 7.7 15 0 88 33 6.5 15 0 - - 31.7 - 21-end 28.4 - 7 6 17.7 11.7 14.7 - 7.1 26 0 103 48 6.1 26 0 - - 25.6 - month 103.6 - 26 22 17.4 11.2 14.3 1.0 7.1 26 0 296 130 6.1 26 0 - - 80.9 -

Co. Monaghan 1-10 34.0 - 9 7 17.5 10.7 14.1 - 5.0 1 0 97 43 2.4 1 0 - - - - Carrickmacross 11-20 26.9 - 7 5 15.9 9.5 12.7 - 6.0 20 0 83 29 4.4 20 0 - - - - 21-end 38.6 - 6 4 17.8 9.6 13.7 - 4.6 26 0 93 40 2.9 26 0 - - - - month 99.5 128 22 16 17.1 9.9 13.5 - 4.6 26 0 273 113 2.4 1 0 - - - -

Co. Waterford 1-10 26.5 - 9 4 18.1 12.2 15.2 - 5.5 4 0 108 53 2.5 4 0 - 14.8 25.5 - Dungarvan 11-20 19.4 - 7 4 17.5 11.3 14.4 - 9.0 17 0 100 44 5.0 17 0 - 13.9 47.4 - 21-end 37.5 - 8 5 17.3 11.3 14.3 - 6.5 26 0 99 44 2.4 26 0 - 14.4 25.5 - month 83.4 - 24 13 17.6 11.6 14.6 1.2 5.5 4 0 306 141 2.4 26 0 - 14.4 98.4 80

Co. Wexford 1-10 34.7 - 6 6 17.0 12.0 14.5 - 6.9 4 0 101 46 n/a 0 14.9 15.8 28.6 - J.F.K. Park 11-20 17.0 - 6 6 16.8 9.8 13.3 - 6.1 14 0 89 35 4.1 14 0 14.0 15.6 47.3 - 21-end 39.7 - 8 5 16.5 11.2 13.9 - 6.8 26 0 94 40 5.0 26 0 13.9 15.2 22.3 - month 91.4 105 20 17 16.7 11.0 13.9 0.9 6.1 14 0 284 121 n/a 0 14.3 15.5 98.2 86

Co. Wicklow 1-10 21.3 - 8 5 18.3 11.4 14.9 - 4.6 4 0 105 52 0.1 4 0 15.2 15.2 28.5 - Ashford 11-20 16.2 - 5 5 17.2 10.7 14.0 - 8.6 15 0 96 40 3.7 15 0 14.2 14.7 42.3 - 21-end 8.6 - 4 2 17.9 10.3 14.1 - 5.8 21 0 97 44 -0.1 21 1 13.8 14.1 24.0 - month 46.1 - 17 12 17.8 10.8 14.3 - 4.6 4 0 297 136 -0.1 21 1 14.4 14.7 94.8 -

P.E. (Penman) GLOBAL SOLAR RADIATION MEASURED POTENTIAL EVAPOTRANSPIRATION (P.E.) (MJ/sq.m.) AND SOIL MOISTURE Station total(mm) 1st-10th 11th-20th 21st-end Total P.E. (mm) Soil Moisture (mm) Co.Carlow Station Period Amount Deficit Accum’ltd Deficit Surplus Carlow (Oak Park)* 46 94.53 98.97 72.15 265.65 Co.Cavan Ballyhaise* 41 96.62 70.97 72.76 240.35 Co. Kerry 1-10 28.5 - 0 25 Co.Clare Valentia Obs. 11-20 18.9 - 0 32 Shannon Airport 44 global solar radiation values for 21-end 26.8 - 0 24 Co.Cork stations marked * are provisional month 74.2 Cork Airport 33 Roche’s Point* 95.65 104.59 74.71 274.95 Co.Donegal Malin Head 45 93.93 74.72 77.52 246.17 Co.Dublin MONTHLY EVAPORATION (MM) FROM CLASS A PAN Dublin Airport 52 106.88 97.51 n/a n/a Casement Aerodrome 50 County Station Monthly Monthly Rainfall (mm) Evaporation (mm) Co Kerry Valentia Obs. 43 90.58 91.80 70.01 252.39 Co.Mayo Kerry Valentia Observatory 160.1 60.2 Belmullet 38 75.81 95.16 82.79 253.76 Kerry North Kerry Landfill 155.4 21.2 Knock Airport 33 Mayo Newport (Furnace) 199.1 25.1 Co.Tipperary Offaly Derrygreenagh 86.6 86.6 Gurteen* 45 98.67 93.66 80.04 272.37 Co.Westmeath Waterford Dungarvan (Carriglea) 83.4 44.9 Mullingar* 42 95.26 89.83 75.93 261.02 Wexford J.F.K. Park 91.4 96.9 Co.Wexford Johnstown Castle* n/a not available 8 DIARY September 2011

Thursday 1st: Dry overnight with some clear spells and light winds. The Rainfall: nil to 12mm, heaviest at Malin Head, nil at Johnstown Castle morning was dry with some sunshine developing in places. Continuing dry Temperature: max. 14°C to 20°C, min. 9°C to 14°C, no ground frost Sunshine: during the early afternoon, however, by late afternoon rain reached parts of the <1 to 3 hours, sunniest at Cork Airport, <1 hour at Knock Airport west and spread further east during the evening. Most eastern parts remained Friday 9th: Some rain and drizzle, mainly in northern parts overnight. The dry. Winds were light, generally southerly in direction. Rainfall: nil to 3mm, heaviest at Claremorris, nil in the east day was mostly overcast but there were some sunny spells, the best of these in Temperature: max. 16°C to 20°C, min. 4°C to 13°C, no ground frost the east. The afternoon saw rain and drizzle along the west coast. Heavy rain Sunshine: trace to 6 hours, sunniest at Dublin Airport, trace at Cork Airport moved in over the southwest during the evening and gradually moved northeastwards over night. Winds; light to moderate, south to southwesterly. Friday 2nd: Early rain and drizzle in the southwest spread eastwards Rainfall: nil to 14mm, heaviest at Valentia, nil at Casement Aerodrome overnight with light winds. The rain cleared the east coast early in the morning, Temperature: max. 16°C to 22°C, min. 11°C to 15°C, no ground frost Sunshine: and mostly dry conditions followed with just the odd sunny spell. Rain along nil to 4 hours, sunniest in the east, nil at Valentia and Cork Airport the west and north coasts during the afternoon, generally dry and cloudy Saturday 10th: Some rain and drizzle overnight in many areas. Rain and elsewhere. During the evening and night rain spread eastwards affecting all areas. Winds; light, south to southwesterly in direction. showers during the early morning, easing somewhat around noon. The Rainfall: trace to 16mm, heaviest at Belmullet, trace at Johnstown Castle afternoon saw showers along the west coast, mostly dry further east with Temperature: max. 15°C to 19°C, min. 11°C to 15°C, no ground frost some good sunny spells. Scattered showers continued during the evening, Sunshine: trace to 2 hours, sunniest at Casement Aerodrome, trace at Cork Airport mainly in the west. Winds; strong and gusty, south to southwesterly. Rainfall: trace to 18mm, heaviest at Belmullet, trace at Malin Head Saturday 3rd: A band of heavy rain over the midlands moved eastwards Temperature: max. 16°C to 21°C, min. 11°C to 14°C, no ground frost during the morning, clearing the east coast around noon. Scattered Sunshine: 1 to 6 hours, sunniest in the east, 1 hour at Belmullet showers in the west during the afternoon, otherwise mainly dry with some sunny spells, the best of these in the southwest. Clear spells after dark away Sunday 11th: Early rain in the west and northwest spread southeastwards, from the northwest. Winds were light, south or southwesterly in direction. heavy in places. The rain cleared the east coast during the late morning and Rainfall: 1 to 9mm, heaviest at Casement Aerodrome, 1mm at Valentia was followed closely by bands of showers, which particularly affected the Temperature: max. 14°C to 18°C, min. 7°C to 11°C, no ground frost northwest and midlands. Another band of rain affected the southwest Sunshine: 1 to 5 hours, sunniest at Valentia, 1 hour at Dublin Airport during the afternoon and moved northeastwards during the evening, giving significant falls of rain in places. Some brief periods of sunshine, Sunday 4th: After a relatively dry start, rain reached the west coast by mid particularly in the south and east. Winds; strong and gusty, southwesterly. morning and spread eastwards during the day. The rain was quickly followed by Rainfall: 3 to 18mm, heaviest at Knock Airport, 3mm at Casement Aerodrome bands of showers and these were heavy and occasionally thundery. There were Temperature: max.15°C to 18°C, min. 10°C to 13°C, no ground frost some good sunny spells during the day in the southwest, but in eastern parts Sunshine: nil to 3 hours, sunniest at Cork Airport, nil at Knock Airport any sunny spells were short-lived. Winds; variable, moderate with gusts. Rainfall: 2 to 12mm, heaviest at Valentia, 2mm at Gurteen Monday 12th Early rain in the northeast cleared quickly. Mainly dry elsewhere Temperature: max. 14°C to 17°C, min. 7°C to 11°C, no ground frost with passing showers. By dawn there were many showers which passed quickly Sunshine: 2 to 5 hours, sunniest at Valentia, 2 hours at Belmullet in high winds. Between the showers there were good sunny spells in the southern half of the country. Feeling mild throughout despite the very high Monday 5th: Some heavy showers overnight. It became dry countrywide for winds. Winds; southwesterly, strong and very gusty throughout. a short while, but rain began to spread into the west by mid-morning, crossing Rainfall: trace to 5mm, heaviest at Ballyhaise, trace at Dublin Airport the country through the afternoon. The rain was most persistent and heaviest Temperature: max. 15°C to 18°C, min. 10°C to 13°C, no ground frost in the northern half of the country. The rain eased off towards evening but Sunshine: 1 to 7 hours, sunniest at Cork Airport, 1 hour at Casement Aerodrome damp, drizzly conditions continued in many areas. It was a generally cloudy day with some sunshine in the east. Winds; variable, moderate to strong and gusty. Tuesday 13th: It remained windy overnight across the country, with Rainfall: 2 to 17mm, heaviest at Belmullet, 2mm at Johnstown Castle showers affecting all provinces. These conditions persisted into the Temperature: max. 14°C to 16°C, min. 6°C to 12°C, no ground frost morning with the showers becoming heavier and more widespread. Despite Sunshine: trace to 4 hours, sunniest at Dublin Airport, trace at Valentia this there were some good spells of sunshine at times. By evening the midlands were mostly dry with showers affecting south Munster and north Tuesday 6th: It was windy and wet overnight with showers across much of Ulster. Winds; westerly, strong and gusty, easing later in the day. the country, heaviest in Munster and Ulster. The morning was bright with Rainfall: nil to 7mm, heaviest at Malin Head, nil at Cork Airport blustery showers. The worst of the showers were confined to the north of the Temperature: max.13°C to 16°C, min. 8°C to 11°C, no ground frost country by the afternoon and became less intense by evening. Winds; Sunshine: 4 to 9 hours, sunniest at Casement Aerodrome, 4 hours at Valentia moderate to strong and gusty, southeast to southwesterly in direction. Rainfall: 2 to 15mm, heaviest at Knock Airport, 2mm at Roches Point Wednesday 14th: Overnight showers in Connacht and Ulster, continued into Temperature: max. 13°C to 16°C, min. 9°C to 12°C, no ground frost the morning. Mostly dry and cloudy elsewhere during the morning with some Sunshine: 2 to 6 hours, sunniest at Dublin Airport, 2 hours at Valentia periods of sunshine in places. The showers in the north moved into central and eastern parts of the country in the afternoon, but were light and scattered Wednesday 7th: Some showers in the west and north overnight. During the and generally died out by evening. Winds were moderate, westerly in direction. morning the showers continued but there were some occasional short sunny Rainfall: nil to 2mm, heaviest at Ballyhaise breaks. Just after midday a more persistent band of rain pushed into the west Temperature: max. 13°C to 16°C, min. 6°C to 12°C, no ground frost from the Atlantic and affected all areas during the afternoon. The rain became Sunshine: <1 to 6 hours, sunniest at Dublin Airport, <1 hour at Belmullet more patchy and scattered by nightfall. Winds; blustery, west to southwesterly. Rainfall: trace to 11mm, heaviest at Shannon Airport, trace at Roches Point Thursday 15th: There was some light rain and drizzle in the northwest Temperature: max. 12°C to 15°C, min. 9°C to 12°C, no ground frost overnight, dry elsewhere. Some sunny spells in all areas during the day, the best Sunshine: nil to <1 hour, sunniest at Dublin Airport of these were in the east. Towards evening a narrow band of rain began to edge into the west and southwest, giving some heavy falls there. Winds were Thursday 8th: It was mild and cloudy overnight with outbreaks of rain and light, southeasterly for much of the day, increasing moderate in the south drizzle across the country. Generally cloudy during the morning with some during the evening. light showers. Into the afternoon there were a few sunny spells, mainly in the Rainfall: nil to 2mm generally, 10mm at Valentia south of the country. Scattered outbreaks of rain became more widespread Temperature: max. 14°C to 18°C, min. 7°C to 11°C, no ground frost towards evening. During the night further rain pushed into the south and Sunshine: trace to 9 hours, sunniest at Dublin Airport, trace at Valentia moved northerly across the country. Winds; light and variable in direction. September 2011 DIARY 9

Friday 16th: A narrow band of heavy rain, already into western Connacht and Rainfall: nil to 15mm, heaviest at Belmullet, nil in the east Munster, continued eastwards during the early hours and through the morning. Temperature: max. 15°C to 17°C, min. 11°C to 13°C, no ground frost Sunshine: A clearance followed into the west. Heavy showers developed through the west trace to 1 hour, sunniest in the east and south and midlands during the afternoon; they became lighter and died back to the Saturday 24th: Early, patchy rain cleared the southeast before morning. Much west later. Broken sunshine in most parts, generally cloudy in the southwest. of the day was dry, however, rain began to spread into the west during the Winds; light southeasterly, veering southwesterly and increasing moderate. Rainfall: 4 to 15mm, heaviest at Mullingar, 4mm at Gurteen evening. Good sunshine everywhere, particularly in the east. Mild for late Temperature: max. 14°C to 18°C, min. 10°C to 12°C, no ground frost September. Winds were moderate, south or southwesterly for most of the day. Sunshine: 1 to 6 hours, sunniest at Casement Aerodrome, 1 hour at Valentia They became light and backed southeasterly in the late evening. Rainfall: nil to 6mm, heaviest at Belmullet, nil at Casement Aerodrome Saturday 17th: Showers continued overnight and were prolonged and heavy Temperature: max. 15°C to 18°C, min. 9°C to 12°C, no ground frost in Ulster. Showers died out in Leinster towards morning, but by early afternoon Sunshine: 5 to 8 hours, sunniest at Casement Aerodrome, 5 hours at Valentia there were heavy showers countrywide and these persisted into the evening. Sunday 25th: Rain in the west overnight, dry elsewhere with variable cloud Some broken sunshine everywhere. Winds; moderate, southwest or westerly, cover. The rain spread slowly eastwards during the morning, with a clearance gradually veering west or northwesterly and increasing during the afternoon. Rainfall: 1 to 14mm, heaviest at Knock Airport, 1mm at Johnstown Castle getting into western parts. Rain in the midlands and east during the afternoon, Temperature: max. 12°C to 15°C, min. 7°C to 11°C, no ground frost heavy and thundery in places. Further west it was dry with some bright spells Sunshine: 3 to 6 hours, sunniest at Valentia, 3 hours at Casement Aerodrome developing. The rain cleared into the Irish sea during the evening with just a few showers lingering. Winds; southerly, moderate to strong and gusty. Sunday 18th: Widespread showery outbreaks of rain countrywide to start, but Rainfall: 1 to 24mm, heaviest at Ballyhaise, 1mm at Dublin Airport these moved quickly southwards and became lighter as the rain moved into Temperature: max. 15°C to 18°C, min. 7°C to 12°C, no ground frost southern parts. Showers continued throughout the day in most places, Sunshine: trace to 3 hours, sunniest at Belmullet, trace at Cork Airport becoming well scattered during the afternoon and early evening. There were Monday 26th: The morning saw some patchy rain along southwest and good sunny spells in places, particularly in the west. A band of rain approached western coasts, with fog along the south coast. Mostly dry elsewhere with some the west coast by nightfall. Winds; moderate, southwest to northwesterly. Rainfall: trace to 3mm, heaviest at Belmullet, trace at Malin Head sunny spells. Some scattered showers in western areas during the afternoon, Temperature: max. 14°C to 17°C, min 10°C to 12°C, no ground frost otherwise dry with some sunny spells. Some patchy rain in western parts during Sunshine: trace to 6 hours, sunniest at Belmullet, trace at Casement Aerodrome the evening and night, with fog returning along the south coast. Winds; south to southwesterly, generally light. Monday 19th: Some rain and drizzle overnight, with fog patches in places Rainfall: nil to 6mm, heaviest at Valentia also. Rain cleared in the west during the morning and some bright spells Temperature: max. 14°C to 17°C, min. 5°C to 10°C, no ground frost developed; patchy rain continued in eastern parts for the morning. Rain in Sunshine: trace to 5 hours, sunniest at Belmullet, trace at Shannon Airport western areas in the early afternoon spread slowly eastwards, not reaching the east coast till after dark. Winds; light, southwesterly in direction. Tuesday 27th: Rain over the northern half of the country moved quickly Rainfall: 1 to 12mm, heaviest at Belmullet, 1mm at Carlow (Oak Park) northeastwards and cleared the northeast coast before dawn. It was a mainly Temperature: max. 15°C to 18°C, min. 9°C to 13°C, no ground frost dry day but there was some drizzle, mist and fog along the south and west Sunshine: nil to 4 hours, sunniest at Belmullet, nil at Shannon Airport coast throughout the day. It was a relatively cool day there while the northeast, east and midlands had a bright, sunny and unseasonably warm day. Winds; Tuesday 20th: The day started with rain in the southeast and some showers in southerly, light to moderate, gusty on north and northwest coasts. the northwest. Showery outbreaks of rain affected western counties and spread Rainfall: nil to3mm, heaviest at Valentia across the country during the late morning. Although these became more Temperature: max. 15°C to 21°C, min. 11°C to 15°C, no ground frost scattered during the afternoon they persisted for the rest of the day in places. Sunshine: nil to 10 hours, sunniest at Dublin Airport, nil in the south and west Good sunny spells in the west, generally dull elsewhere. Winds; light to moderate, westerly, backing southerly during the evening. Wednesday 28th: Very mild overnight with rain, drizzle, fog and mist along Rainfall: nil to 3mm, heaviest at Gurteen southern and western coasts. While the cloud, mist and sometimes dense fog Temperature: max. 14°C to 15°C, min. 7°C to 11°C, no ground frost persisted along south and southwest coastal parts, the rest of the country had a Sunshine: 1 to 6 hours, sunniest at Belmullet, 1 hour in the southwest fine day with exceptional temperatures for the time of year. In the late afternoon a band of rain began to move in over the southwest and moved Wednesday 21st: During the early morning a band of rain pushed into the northeastwards across the country throughout the evening. The rain tended to northwest. This moved slowly southeastwards across the country during the die out as it moved eastward. Winds; light to moderate, southerly in direction. morning and afternoon. A clearance followed with some scattered showers Rainfall: nil to 6mm, heaviest at Valentia and spells of sunshine. Generally dry by nightfall with some drizzle near Temperature: max. 15°C to 24°C, min. 13°C to 16°C, no ground frost coasts. Winds; south to southwesterly, moderate to strong and gusty. Sunshine: nil to 11 hours, sunniest in the east, nil at Cork Airport Rainfall: trace to 8mm, heaviest at Mullingar, trace at Roches Point Temperature: max. 14°C to 16°C, min. 8°C to 12°C, no ground frost Thursday 29th: Overnight rain in the west and northwest. It was a bright Sunshine: 1 to 6 hours, sunniest at Belmullet, 1 hour at Valentia start to the day in the eastern half of the country with overcast conditions in the west. Some drizzle in southern coastal areas, but precipitation amounts Thursday 22nd: Generally dry overnight. The morning was dry and bright at were small. Generally dry overnight apart from some precipitation affecting times in the north and east, cloudier in the west with some rain and drizzle over west and southwest coasts. Winds; light, southerly in direction. Munster. It continued mainly dry during the afternoon throughout. Some rain Rainfall: nil to 3mm, heaviest at Knock Airport, nil in the east and drizzle in western and northern coastal areas overnight, but precipitation Temperature: max. 15°C to 22°C, min. 12°C to 16°C, no ground frost amounts were small. Winds; light to moderate, generally southwesterly. Sunshine: nil to 10 hours, sunniest at Casement Aerodrome, nil at Cork Airport Rainfall: nil to trace generally, 2mm at Gurteen Temperature: max. 14°C to 17°C, min. 6°C to 13°C, no ground frost Friday 30th: A band of heavy and persistent rain moved into the west from Sunshine: trace to 5 hours, sunniest at Cork Airport, trace at Knock Airport the Atlantic overnight. By morning it affected the western half of the country. The rain crossed the country during the late morning and by the afternoon had Friday 23rd: Rain across the northern half of the country, cleared most places reached the east coast. There were some very heavy falls accompanied by by dawn. It remained dry and generally overcast for a number of hours until a thunder in the east. A clearance followed in the west with some occasional more active rain-bearing front arrived on the west coast in the late afternoon. sunny breaks. Winds; light to moderate, variable in direction. This brought heavy spells of rain to parts of the western seaboard, however, Rainfall: 4 to 47mm, heaviest at Carlow (Oak Park), 4mm at Johnstown Castle some eastern and southern areas remained completely dry. Just a few sunny Temperature: max. 15°C to 21°C, min. 8°C to 14°C, no ground frost spells. Winds; southerly, moderate to strong and gusty. Sunshine: nil to 1 hour, sunniest at Valentia 10 RAINFALL September 2011 Above average rainfall in County/ * 9-9 totals Total* % of Number of Amount 1961-90 Most in Raindays Wetdays most parts Station (mm) average a day / date* (>0.2mm) (>1mm) Rainfall amounts were highest CO. CARLOW along western coasts, with lowest CARLOW (OAK PARK) 95.5 134 48.1 30 21 16 totals in some locations in the CO. CAVAN midlands and east. The driest BALLYHAISE 126.8 156 23.7 25 26 18 location in September was CAVAN (LORETO COLLEGE) 125.8 not available CO. CLARE Ashford (Cronykeery), Co. SHANNON AIRPORT 91.1 111 11.9 7 24 20 Wicklow with 46.1mm of rainfall CARRON 218.0 154 33.1 5 28 26 for the month. Maam Valley, Co. CO. CORK Galway, was the wettest, ROCHE’S POINT 89.4 99 9.6 2 22 18 CORK AIRPORT 112.5 116 16.8 29 24 18 recording the months highest SHERKIN ISLAND 114.2 119 26.1 29 27 20 total rainfall of 406mm and BALLINCURRIG (PEAFIELD) 124.0 16.2 29 25 18 September’s highest daily fall of CO. DONEGAL 76.1mm on the 5th, both the MALIN HEAD 133.0 130 17.0 16 23 21 GLENTIES HATCHERY 214.4 148 20.1 11 29 27 highest on record for September BALLYSHANNON(CATHLEEN'S FALL) 120.8 117 13.2 11 26 23 for the station since records CO. DUBLIN began in 1983 (28 years). The DUBLIN (PHOENIX PARK) 72.6 106 30.5 30 20 12 majority of percentage of normal DUBLIN AIRPORT 87.3 42.1 30 19 15 CASEMENT AERODROME 81.2 128 30.1 30 16 12 values for the month were above DUBLIN (MERRION SQUARE) 58.1 94 33.4 30 16 11 normal, ranging from 80% at CO. GALWAY Johnstown Castle, Co. Wexford to GALWAY (UNIV.COLL.) 135.5 124 20.1 2 28 25 162% at Belmullet, Co. Mayo, its MAAM VALLEY 406.1 76.2 5 29 27 CO. KERRY highest September rainfall since VALENTIA OBSERVATORY 160.1 128 19.5 29 26 25 1985 (26 years). ARDFERT (LISCAHANE) 103.6 11.2 9 26 22 CO. LIMERICK The majority of the highest daily MOUNT RUSSELL 109.0 19.8 29 28 22 CO. MAYO falls for the month fell in the last BELMULLET 175.1 162 18.9 5 27 24 few days of September, with Carlow STRAIDE 141.6 135 17.7 5 29 25 (Oak Park) recording the month’s KNOCK AIRPORT 162.6 15.1 5 30 26 second highest daily fall of 48.1mm DELPHI LODGE II 335.8 36.5 5 28 28 on the 30th. All stations measured CO. MEATH (days with WARRENSTOWN 102.8 134 29.2 30 20 14 between 11 and 28 wetdays CO. MONAGHAN 1mm or more of rainfall). Fewest CARRICKMACROSS (DUNOGE) 99.5 128 24.0 30 22 16 wetdays were recorded in the east CO. OFFALY and southeast, which is slightly DERRYGREENAGH 86.6 108 17.5 30 25 17 below average for the time of year, CO. SLIGO ARDTARMON 140.8 16.1 6 28 25 with remaining stations across the CO. TIPPERARY country recording an above average GURTEEN 91.1 13.3 2 25 20 number of wetdays during FETHARD (PARSONSHILL) 94.6 12.4 25 28 19 September. CO. WATERFORD WATERFORD (TYCOR) 77.5 90 25.6 30 20 13 DUNGARVAN (CARRIGLEA) 83.4 23.0 30 24 13 CO. WESTMEATH MULLINGAR 122.6 142 19.5 5 27 20 CO. WEXFORD JOHNSTOWN CASTLE 68.3 80 10.9 30 21 13 JOHN F. KENNEDY PARK 91.4 105 27.0 30 20 17 CLONROCHE (KNOXTOWN) 87.1 28.3 30 19 14 CO. WICKLOW ASHFORD (CRONYKEERY) 46.1 8.5 9 17 12 September 2011 RAINFALL 11

Total rainfall (mm)

Percentage of normal rainfall

Daily 0-24h rainfall values(mm) 20

Valentia Observatory Dublin Airport Belmullet 12 TEMPERATURE September 2011 Warmer than normal temperatures everywhere Mean air temperatures for September were above normal for the time of year, with the majority of the coolest temperatures recorded in the south and southwest. Mean air temperatures for the month ranged from 12.2°C at Knock Airport to 14.9°C at Dublin (Merrion Square), its warmest September since 2006. The highest temperature differences above normal were at Warrenstown, Co. Meath and Derrygreenagh, Co. Offaly, both with 1.7°C above their averages for the month and the warmest September for both in five years.

The month’s highest temperatures were mainly recorded on the 9th and 28th, with the highest value of the month of 25.7° C recorded at Dublin (Phoenix Park) on the 28th, its highest temperature at the site during September, in over 100 years. The month’s lowest air temperature was at Glenties Hatchery, Co. Donegal on the 5th, with 3.4°C, its Mean Temperature warmest minimum temperature since 2006, while (difference from 1961-90 normals) the September minimum air temperature recorded temperatures for the month were above zero at Maam Valley, Co Galway of 9.4°C was the degrees, with a below average number of ground warmest on record for the site since it opened in frosts recorded for the time of year. 1983 (28 years). Almost all grass minimum

Daily 0-24h maximum temperatures (°C)

Daily 0-24h minimum temperatures (°C)

l Valentia Observatory l Dublin Airport l Belmullet September 2011 TEMPERATURE 13 °C County/ Mean/ deviation Mean Mean from 1961-90 Highest Lowest Lowest Days with Station max. min. average max./date min./date grass min./date air frost ground frost CO. CARLOW CARLOW (OAK PARK) 17.2 10.9 14.1 0.9 21.1 28 6.2 26 1.3 1 0 0 CO. CAVAN BALLYHAISE 16.3 10.9 13.6 20.8 9 5.7 5 2.0 5 0 0 CAVAN (LORETO COLLEGE) 16.8 10.8 13.8 20.9 9 6.1 5 1.7 5 0 0 CO. CLARE SHANNON AIRPORT 16.9 11.7 14.3 0.6 21.4 9 7.8 26 3.7 26 0 0 CARRON 16.1 10.4 13.3 1.0 19.6 9 6.4 26 -1.3 26 0 2 CO. CORK ROCHE’S POINT 15.8 11.7 13.8 0.2 19.5 8 8.1 14 3.8 26 0 0 FERMOY (MOOREPARK) 16.6 10.8 13.7 21.2 8 5.2 14 1.2 4 0 0 CORK AIRPORT 15.6 10.4 13.0 0.2 20.1 8 6.1 14 0.8 26 0 0 SHERKIN ISLAND 16.0 12.0 14.0 0.3 18.0 1 2 8.6 15 5.5 3 0 0 BALLINCURRIG (PEAFIELD) 16.5 10.1 13.3 22.7 8 5.1 14 5.0 14 0 0 CO. DONEGAL MALIN HEAD 16.3 11.5 13.9 1.1 23.4 28 7.5 15 4.1 15 0 0 GLENTIES HATCHERY 16.5 10.8 13.7 1.4 22.5 28 3.4 5 0.4 5 0 0 BALLYSHANNON(CATHLEEN'S FALL) 16.6 10.8 13.7 1.0 23.0 28 6.6 26 0 CO. DUBLIN DUBLIN (PHOENIX PARK) 18.1 11.1 14.6 1.6 25.7 28 6.2 1 1.0 4 0 0 DUBLIN AIRPORT 17.4 10.9 14.2 24.1 28 3.9 1 0.4 1 0 0 CASEMENT AERODROME 17.3 11.1 14.2 1.3 24.4 28 7.2 26 2.5 1 0 0 DUBLIN (MERRION SQUARE) 17.9 11.9 14.9 0.8 25.3 28 7.1 1 0 CO. GALWAY GALWAY (UNIV.COLL.) 17.1 11.4 14.3 0.9 21.1 27 7.1 15 2.0 15 0 0 MAAM VALLEY 16.4 11.2 13.8 20.2 9 9.4 5 6.5 5 0 0 CO. KERRY VALENTIA OBSERVATORY 16.3 12.0 14.2 0.5 19.0 28 8.3 15 1.7 26 0 0 ARDFERT (LISCAHANE) 17.4 11.2 14.3 1.0 21.9 28 7.1 26 6.1 26 0 0 CO. LIMERICK MOUNT RUSSELL 16.1 10.6 13.4 21.0 8 7.8 26 4.1 15 0 0 CO. MAYO BELMULLET 15.9 11.7 13.8 0.8 20.1 28 7.4 5 4.9 5 0 0 STRAIDE 16.8 11.0 13.9 1.4 21.6 28 3.7 26 -0.7 26 0 1 KNOCK AIRPORT 14.9 9.5 12.2 20.6 28 5.4 26 2.8 26 0 0 DELPHI LODGE II 16.0 11.9 14.0 20.1 29 9.1 26 3.6 26 0 0 CO. MEATH WARRENSTOWN 17.4 11.1 14.3 1.7 22.9 28 6.0 4 2.2 1 0 0 CO. MONAGHAN CARRICKMACROSS (DUNOGE) 17.1 9.9 13.5 22.6 28 4.6 26 2.4 1 0 0 CO. OFFALY DERRYGREENAGH 17.3 10.4 13.9 1.7 22.0 9 6.1 26 0.2 26 0 0 CO. SLIGO ARDTARMON 17.2 11.3 14.3 22.5 28 7.8 26 3.0 26 0 0 CO. TIPPERARY GURTEEN 16.5 10.6 13.6 20.6 9 6.4 26 1.6 26 0 0 FETHARD (PARSONSHILL) 16.5 10.0 13.3 20.0 1 6.0 14 5.2 14 26 0 0 CO. WATERFORD WATERFORD (TYCOR) 17.0 11.9 14.5 1.2 20.4 8 8.1 26 0 DUNGARVAN (CARRIGLEA) 17.6 11.6 14.6 1.2 22.1 8 5.5 4 2.4 26 0 0 CO. WESTMEATH MULLINGAR 16.7 10.3 13.5 22.2 9 5.0 26 1.6 26 0 0 CO. WEXFORD JOHNSTOWN CASTLE 16.3 11.1 13.7 0.7 19.1 1 6.9 14 8.1 5 0 0 JOHN F. KENNEDY PARK 16.7 11.0 13.9 0.9 21.0 9 6.1 14 n/a n/a 0 0 CLONROCHE (KNOXTOWN) 16.5 10.4 13.5 20.1 8 4.1 26 1.9 26 0 0 CO. WICKLOW ASHFORD (CRONYKEERY) 17.8 10.8 14.3 20.9 9 28 4.6 4 -0.1 21 0 1 14 SUNSHINE September 2011

County/ Below average everywhere; Daily mean % of % of Most in most sunshine in the east Station (hours/day) average possible a day/date Sunshine totals were below normal for September, with totals in the Dublin area CO. CAVAN around average for the time of year. The CAVAN (LORETO COLLEGE) 2.50 9.6 28 majority of stations in the south and CO. CLARE southwest, reported it was the dullest SHANNON AIRPORT 2.45 66 19 6.7 13 September in 25 years or more. Totals CO. CORK ranged from 57 hours at Valentia CORK AIRPORT 2.28 56 18 8.7 13 Observatory, its dullest September since SHERKIN ISLAND 3.31 75 26 8.7 14 1893 (118 years) to 120 hours at Dublin BALLINCURRIG (PEAFIELD) 2.56 8.4 13 Airport. Percentage of normal values CO. DONEGAL ranged between 53% at Valentia Observatory and 94% at Dublin Airport. BALLYSHANNON(CATHLEEN'S FALL) 2.61 80 20 7.3 28 Casement Aerodrome reported the CO. DUBLIN highest daily sunshine of the month with DUBLIN AIRPORT 4.00 94 31 10.4 28 10.6 hours on the 28th. CASEMENT AERODROME 3.72 92 29 10.6 28 CO. GALWAY Global solar radiation totals were below average. Percentage of normal values ranged GALWAY (UNIV.COLL.) 2.71 75 21 7.5 13 from 80% at Valentia Observatory to 91% at CO. KERRY Belmullet. VALENTIA OBSERVATORY 1.89 53 15 6.2 17 ARDFERT (LISCAHANE) 2.70 21 7.0 24 CO. MAYO BELMULLET 2.71 75 21 6.4 24 21 STRAIDE 2.51 7.8 13 KNOCK AIRPORT 2.24 7.7 13 CO. WATERFORD DUNGARVAN (CARRIGLEA) 3.28 80 26 9.1 12 CO. WEXFORD JOHN F. KENNEDY PARK 3.27 86 26 9.3 13 CLONROCHE (KNOXTOWN) 3.00 9.1 13 CO. WICKLOW ASHFORD (CRONYKEERY) 3.16 25 8.7 14

Total Sunshine (percentage of 1961-90 normals) Daily sunshine values(hours)

Valentia Observatory Dublin Airport Belmullet September 2011 MARINE & PRESSURE 15 MARINE OBSERVATIONS FROM IRISH MARINE DATA BUOY NETWORK

Sea Mean Max. Mean Max. Buoy surface wind 10-min wave wave temp. speed wind height height (°C) (knots) (knots) (m.) (m.) M2 14.3 15.9 34.6 1.3 3.4

M3 14.8 n/a n/a 3.6 8.2

M4 13.3 17.5 36.7 3.5 9.2

M5 14.6 16.4 31.0 2.1 5.6

M6 13.7 18.8 41.0 3.6 8.2

Malin 13.7 Head Summary of Mean Monthly Values l Malin Head

M4t

t M2 M6

t M5 Hourly wind and wave conditions at M5 (51.7°N, 6.7°W) M3 t

MEAN ATMOSPHERIC PRESSURE Mean sea level pressure values for September varied between 1004 hPa and 1010 hPa, which is well below normal for the time of year of between 1010 hPa and 1013 hPa. September’s absolute maximum MSL pressure was recorded at Johnstown Castle, Co. Wexford on the 27th, with 1025.9 hPa. The month’s lowest absolute MSL pressure of 977.8 hPa recorded at Belmullet, Co. Mayo on the 12th, was due to the passing of Post- Tropical Storm Katia. Monthly mean MSL pressure, based on 1200 UTC values

Mean daily Mean Sea Level pressure (hPa) 16 WORLD WEATHER September 2011

% SEPTEMBER RAINFALL (percentage of 400 1961-1990 normal) 200

150

125

100

75

50

25

0

°C

+7 SEPTEMBER MEAN +5 TEMPERATURE +3 (difference from +1 1961-1990 normal) -1 -3 -5 -7 Data supplied by NOAA Climate Prediction Centre, US Department of Commerce

In China, more than a week of The sweltering heat that gripped the Preliminary data from the National Snow & Ice heavy rains during mid-September, led to southern United States throughout the summer, Data Center indicate that on September 9th, Arctic sea ice at least 57 deaths and affected 12.3 million continued to set records into the first half of extent reached its second lowest value on record, behind residents in the southwestern and central September. On the 13th, Wichita Falls, Texas 2007. This year continues a trend of declining sea ice, with provinces of Sichuan, Henan, and Shaanxi. recorded its 100th day of 100°F (37.8°C) in satellite records dating back to 1979. The floods were the worst in Sichuan since 2011, shattering the old record of 79 days set in records began in 1847. More than 120,000 1980. This is the first time in recorded history houses were destroyed and economic that any Texas locale has achieved this In northern and northeastern losses were initially estimated to be $2.7 distinction. That same day, Dallas/Fort Worth, Thailand, monsoon rains and related flooding billion U.S. dollars. Texas recorded its most 100°F days in a calendar and landslides led to at least 224 deaths since late year with 70 days, breaking the previous record July when Tropical Storm Nock-Ten hit the set in 1980. The record was broken when the country. More than 300,000 homes were either temperature reached 107°F (41.7°C) on the 70th damaged or destroyed across 29 provinces and 3 day, surpassing the previous daily record set in million acres (1.2 million hectares) of cropland 1965 by a full 7°F (4°C). were submerged. The monsoon season lasts from August to October in Thailand. Global weather highlights of the month