Winter 2008/9 Review

Danno

Here is a review of Winter 2008/9 as recorded by my AWS, located in South Co. Laois.

DECEMBER 2008

December was a month of two distinct halves. The month began very cold with many night frosts. Indeed, five out of the opening seven nights produced frost, with the months low of -4.6c recorded on the 7th. The very cold theme continued and by the end of the second week, eleven of the fifteen opening days returned a recorded frost. The opening 15 days returned a mean of just 3.53c. From day 16 on to the 25th the country was under the influence of a Euro high. This gave mild weather with nothing in the way of night frosts. The maximum temperature for December, and indeed Winter as a season, was recorded on the 21st (The shortest day) with a value of 12.9c. The Euro high began to drift northwards at months' end bringing in cooler weather. Five out of the last 7 days recorded a frost.

The month was also characterised by periods of very low pressure and periods of very high pressure. December 4th and 5th brought a low pressure cell across the country with 976hpa recorded. Fortunately much of the strong winds stayed off the south coast, but alot of rain did fall with 15mm recorded over both days. Pressure quickly rose after and 1030hpa was recorded by the 9th. Another low wound up and pushed alot of rain in over the country, with another 15mm dousing on the 12th. The cold sector that followed on gave snow showers and the first snow of the winter proper fell early on the 14th here. Indeed, the 14th gave the second lowest daily high for that month of 5c. Pressure then rose to stay between 1020hpa and the highest recorded 1039hpa for the rest of the month.

Rainfall for the month was 57.4mm. Around 80mm would be expected in this area in any given December, so it was rather drier than average. Two major low pressure cells were responsible for the rainfall on the 4th/5th and again on the 11th/12th. According to the computer, 22 days recorded rainfall in December, however visual observations would testify that quite a few of these rain days were actually frost melt accumulating in the rain bucket. 8 days recorded over 2mm which would be a fairer reflection on the distribution of rain over the month.

In summary, the month was a colder than average one with temperatures being 0.15c below average. The mean for the month was 5.2c. Rainfall was roughly 70% of normal with 57.4mm and winds were light throughout. Pressure was mostly higher than average. Over the course of the month 16 nights recorded a minimum of 2c or less, with 11 air frosts - 0c or less recorded.

JANUARY 2009

January was the coldest month of the winter, and the first week delivered a cold spell not seen for a few years. An east wind brought in quite dry air and low temperatures. The lowest temperature of -7.0c recorded at 7am on the 7th January was the coldest at the location for the winter as a whole. The first 10 days delivered a frost every night. The days were very cold too with no real thawing. Indeed, water pipes froze for three days from the 7th to the 10th. By the 11th though, the wind and rain was back as a new weather type took over for much of the remainder of the month. A series of low pressure cells - with very low pressure values - crossed the country from west to east. These low pressure cells were responsible for alot of rainfall.

Despite the low pressure, the wind was never overly strong. The 17th brought the windiest day of the winter with loss of power at the station. After the big wind that day another spell of snow showers pushed in from the west, a serious squall of hail and snow fell around 9pm on the 17th. The cold stayed for a few days with a mixture of wintry showers and another snowfall on the 19th. The snow thawed quickly, but remained on hilltops above 200m for another two days. Another spell of wind gave a 34mph gust here on the 24th, but again the low pressure values still failed to deliver anything with serious punch. By the 25th, a low pressure reading of 966.6hpa was registered at the AWS.

The final week marked a transition to the snowiest spell of the winter that marked the beginning of February. A cold pool was beginning to build to our east over Germany, the Atlantic was starting to weaken after sending in a series of low pressure cells. The final low pressure cell would only make it to Belmullet before being shunted back out west again. The associated fronts with this cell arrived on Thursday and continued to dump rain until Saturday night. A total of 44.5mm fell from the front. This was the wettest spell of the entire winter which included the wettest day, January 30th with a daily total of 26.2mm.

Summarising the month, it was bang on average temperature wise with a 4.6c mean. Rainfall was well above average with a massive 156mm recorded. 80mm would be normally expected in January at this location. So, around 190% of average rainfall fell. Winds were light to moderate throughout and only two days of anything remotely strong. Pressure was very low for the final two weeks, after a rather high start to the month, a low of 966.6hpa gave a record for the station. Over the course of the month 22 nights recorded a minimum of 2c or less, with 8 air frosts - 0c or less recorded.

FEBRUARY 2009

February delivered the snowiest spell of weather for several years at the location, but also was a month of two distinct halves. Sunday 1st of February brought a clear blue sky day, which was polarized after the non-stop rain of the previous three days. On Monday 2nd, a large amount of lake-effect snow caused by the Irish sea gave up to 4 inches of snowfall in the area. The cold weather remained for the rest of the week with snow falling and lying every morning at 9am. Many of the afternoons saw the snow melting completely away, but returning overnight. Despite the amount of snow, the lowest temperature of -2.3c was recorded on the 7th and would stand as the coldest recorded for the month.

Pressure began to rise in the south and southwest which fed in a milder westerly airflow, this pattern remained for the rest of the month with hardly any rainfall. The high pressure was a very cloudy one, many cloudy days without any sunshine were noted. The night time minimums were kept very high due to the cloud. Indeed, from the 12th until months end, there were only three nights where an air frost was recorded and only three days had maxima below 10c.

In summary, the month was a warmer than average one with temperatures being 0.60c above average. The mean for the month was 5.4c. Rainfall was well below average with a paltry 20.1mm recorded. 60mm would be normally expected in February at this location. So, around 33% of average rainfall fell. Winds were light throughout. Over the course of the month 15 nights recorded a minimum of 2c or less, with 9 air frosts - 0c or less recorded.

OVERVIEW OF WINTER 2008/9

Average temperature was slightly above average. 4.92c is the average for this location. This winter, 5.06c was the average recorded.
Total rainfall recorded was 233.5mm, with 225mm being the average for this area during winter. So an average winter was recorded.
28 Air frosts were recorded over the three months, with 53 nights reporting a low of 2c or less.
Snow was reported as falling on approx 12 days with lying snow for approx 7 days.

mike65

No stats obviously, but I'm surprised at yours Danno. Higher than average temps and much more rain in January. The opposite felt to be the case in east Waterford. February was clearly pretty dry and quite mild.