Fair Isle Weather - November 1998

Slightly cooler (-0.4°C) than average, wetter (124.1%), but with hours of sunshine (148.0%) well above normal.

Shetland as a whole was also sunny. Lerwick, with 57.7 hours (186.1%) sunshine during the month, recorded its sunniest November on record. Like Fair Isle, rainfall was also above average (112.1%) but, unlike here, at Lerwick the monthly mean temperature was slightly above average (+0.3° Celsius).

With pressure low over the North Sea and fresh N to NE’ly winds across Scotland, the month began cold with mean daily temperatures some 3° Celsius below normal. During the first few days further lows, tracking east across the south of the British Isles, maintained the cold N to NE’ly airflow.

Early on the 5th, as winds eased, temperatures fell quickly to the month’s lowest of 0.6° Celsius in the air and –1.3° Celsius on the grass. Later in the day a low then ran east across Northern Scotland followed, early on the 6th, by a weak ridge of high pressure. A small low, moving quickly north-east, brought a very wet end to the day with 21.6 mm measured by 09 hours the following morning.

By the 7th a deepening Atlantic low – the remnants of ex-hurricane ‘Mitch’ – was tracking north-east towards the British Isles. It then turned northwards, moving to a position off Western Scotland on the 8th, with heavy rain and SE’ly winds increasing gale to severe gale force across Shetland. Winds then veered SW’ly and eased temporarily early on the 9th, allowing the temperature to rise to the month’s maximum of 11.0° Celsius. Winds soon increased, reaching storm force over exposed parts of Shetland and gusting to 66 kt on Fair Isle, as the depression continued north past Shetland and on across the Faeroes. The 10th was a blustery day with strong to gale force SW to W’ly winds across the North.

High pressure, building to the south of the UK, developed a ridge northwards on the 11th. This moved quickly east as the next Atlantic low headed quickly north-east across Scotland. The 13th and 14th saw a complex area of low pressure across the UK but, as this moved away across the North Sea, N’ly winds brought a spell of cold showery weather for the next few days.

High pressure then developed south across Iceland towards Scotland, with winds gradually falling light across the area for the next few days. As high pressure drifted away towards Norway on the 19th, Atlantic weather systems with strengthening SE’ly winds edged towards Scotland. High pressure hanging on over Scandinavia delayed eastwards progress of the fronts until a deepening Atlantic low, moving north towards Iceland, finally drove the fronts east across Shetland on the 20th.

For the next few days Atlantic lows, tracking north-east between Scotland and Iceland, maintained the mild SW’ly winds as a series of fronts pushed east across Shetland. On the 26th a small low, slipping south-east across Scotland, was followed by a narrowing ridge of high pressure. NW’ly winds soon backed SW’ly again later on the 27th as the next deep low moved north towards Iceland, bringing a mild end to the month with rain and strong SW’ly winds.

Daily Data
Weather Diary

1998

Day

1974-98

1998

Day

1974-98

Mean Maximum Temperature

7.7

8.1

Highest Max temp

11.0

9

13.1

Mean Minimum Temperature

4.8

5.4

Lowest Min temp

0.6

5

-3.2

Mean Sea Temperature

9.8

9.4

Lowest grass minimum

-1.3

5

-9.0

30 cm Earth temperature

6.5

7.3

Days with ground frost

8

5.5

100cm Earth temperature

7.5

8.2

Days with air frost

0

1.0

Total Rainfall (mm)

143.6

116.8

Days with snow/sleet

8

6.3

Wettest Day (mm)

22.2

6

19.2

Days with snow cover at 09hr

0

1.0

Rain Days (> 0.1mm)

27

23.6

Days with hail

10

10.5

Wet Days (> 0.9mm)

22

19.4

Days with fog during 24hrs

2

2.0

Total sunshine, hrs

53.5

36.9

Days with fog at 09hrs

1

0.2

Sunniest day, hrs

5.0

2

5.0

Days with NIL sun

9

10.7

Mean wind speed, kts

16.8

18.5

Days with gale

4

7.2

Maximum gust, kts

66

9

62.1

Days with thunder

1

0.6

Mean Sea Level pressure

1009.7

1007.1

Days with aurora

3

3.9

Wind Direction (%) North

13.3

12.8

Wind Direction (%) S. West

10.0

15.5

at 09 hr N. East

3.3

3.9

at 09 hr West

16.7

17.2

East

10.0

6.7

N. West

3.3

9.9

S. East

16.7

11.3

South

26.7

20.4

CALM

0.0

2.3

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Weather Diary - November 1998

  1. Showers overnight turning wintry with rain, snow and small hail by morning.

  2.  
  3. Rainsnow and small hail showers overnight. 1352-1354 UTC heavy hail shower with hail to 10mm diameter. The hail was conical in shape and white in colour on one side, with a translucent rounded hemisphere on the other. The sound of falling hail was heard some 30 seconds before it arrived.

  4. Some snow deposits above 400 ft.

  5. Hill 'white' down to 300ft by dawn.

  6.  
  7.  
  8. Rain and SE gale overnight, cloud breaking after 0700 UTC. Gale 0310 - 0600 UTC.

  9. Gale 0425 - F9 1525 UTC, gust 66 kt at 1645 UTC - F8 following the gust. 1830 UTC lightning, to south, with thunder. Gale ceased 1930 UTC, Gale 2010 - 2125 UTC. Rain and small hail showers from 2157 UTC.

  10. Heavy hail 1340 - 1345 UTC.

  11.  
  12. A few very light showers during the afternoon.

  13. Rain from mid-morning turning to showers mid-afternoon.Gust to 52 kt at 2147 UTC.

  14.  
  15. Moderate aurora arch late evening.

  16. Moderate aurora glow late evening.

  17.  
  18.  
  19.  
  20.  
  21. 2025 UTC wind veer 210°-250°.

  22. 2215 UTC wind backing 230°-180°.

  23. Gale from 2015 UTC. Rain from 20205 UTC.

  24. Gale ceased 0245 UTC.

  25. Strong aurora arch late evening.

  26. Rain from 0630 UTC, moderate at times 06 55 - 0800 UTC, ceased 1030 UTC. 1410 UTC wind veer 240°-280° and increase from 10 kt to 22 kt mean.

  27.  
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Last edited on 10 January, 1999   Dave Wheeler weatherman@zetnet.co.uk
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