WEATHER OUTLOOK FOR SHETLAND
Tuesday, 29th November 2011 at 15:42
TODAY: RAIN AT TIMES
TONIGHT: SHOWERS, WINDY
TOMORROW: EARLY SHOWERS, RAIN LATER, WINDY
DAYS 3-5: CHANGEABLE, COOLER
DAYS 6-10: POSSIBLY WINTRY
Cloudy today with outbreaks of rain. Orkney becoming drier and brighter later in the afternoon, and the rain clearing Shetland this evening. Mostly light S’ly winds increasing fresh or strong SW’ly later. Showers becoming more frequent and blustery overnight.
Showers dying out on Wednesday, with rain spreading up from the southwest later. SW’ly gales developing and increasing severe overnight.
Rain clearing to showers on Thursday, these turning wintry as gale or severe gale-force SW’ly winds – perhaps storm F10 for a time across Orkney – veer NW’ly. The showers dying away Friday morning as NW’ly gales moderate and back fresh SW’ly. More rain following overnight as a strengthening SW’ly wind again reaches gale-force.
Becoming colder over the weekend, with showers turning wintry as SW’ly winds veer NW or N’ly.
Possibly a wintry start to next week with strong NW or N’ly winds. Less cold after midweek as winds back to a lighter W’ly.
GENERAL SITUATION AND SYNOPSIS 06:00 UTC
Pressure is presently low to the northwest, with a cold front slow-moving over the Northern Isles. A wave – developing on the front west of the Hebrides – will run northeast over the Northern Isles today, a light S’ly airflow becoming a freshening SW to W’ly as it does so.
During Wednesday a depression will track north to the west of the UK to become a deep feature between Scotland and Faeroe by the evening. As it does so a SW’ly airflow will strengthen. On Thursday this vigorous low is expected to track east to the north of Shetland, with the strong SW’ly airflow veering to a colder NW’ly as it does so.
The NW’ly airflow will ease and back W’ly on Friday as the low moves away northwards and a flat ridge moves east over Scotland. This will soon decline, with a milder SW’ly airflow developing ahead of fronts pushed towards Scotland by a depression moving east to the south of Iceland. The fronts will continue east across the Northern Isles overnight.
During the weekend the depression is expected to continue east into the Norwegian Sea with a strong SW’ly airflow veering to a colder NW’ly.
The depression is forecast to move away over northern Scandinavia early next week, resulting in a cold NW to N’ly airflow over northeast Scotland. A ridge is predicted to move east over Scotland midweek, cutting off the supply of Arctic air as it does so.
FORECAST FOR NEXT THREE DAYS
Confidence level: Weather type – medium/high. Timing – medium/low.
Temperatures today rising to around 10° Celsius, but much cooler tonight with a low of about 2° or 3° Celsius. Temperatures on Wednesday and at first on Thursday in the range 8° Celsius down to 5° Celsius. Turning cooler later on Thursday.
TUESDAY 29th: Cloudy with outbreaks of occasionally heavy rain, accompanied by patchy hill fog, more so this morning. Across Orkney the rain will die out through the afternoon with some brightness by dusk. Shetland becoming drier an hour or so later with most places seeing some clear intervals and a scattering of showers through the evening. Mainly F2-4 S’ly winds at first, but freshening F5-6 SW’ly after dark. The showers becoming more frequent and blustery, perhaps with hail, overnight as SW to W’ly winds increase F6-7.
Sea state – Rough, with a 3 to 4 metre SW’ly wind-swell.
WEDNESDAY 30th: Bright at first with fairly frequent showers and a F5-7 SW’ly wind. The showers tending to die out through the day, but then clouding over with rain spreading up from the southwest into Orkney during the late afternoon to reach Shetland by the evening. SW’ly gales developing and increasing severe overnight.
Sea state – Moderate to rough, with a 2 to 3 metre SW to W’ly wind-swell.
THURSDAY 1st: Rain clearing to showers during the morning, The showers then turning wintry as gale or severe gale-force SW’ly winds – perhaps storm F10 for a time across Orkney – veer NW’ly.and it turns colder.
Confidence level: Weather type – low/medium. Timing – low.
Less cold on Monday, with temperatures rising to around 9° Celsius. Then becoming colder again, with temperatures in the daily range 6° to 8° Celsius down to 4° Celsius overnight.
FRIDAY 2nd: The showers dying away by morning as overnight NW’ly gales moderate and back fresh SW’ly. The day then mostly dry and bright with a strengthening SW’ly wind reaching gale force by the end of the day as rain spreads northeast.
SATURDAY 3rd: Rain clearing to blustery showers as SW’ly gales ease and veer fresh to strong W’ly. Becoming colder through the day, with the showers turning wintry.
SUNDAY 4th – FRIDAY 9th: Cold on Sunday with wintry showers perhaps turning more to snow even at lower levels. Strong to possibly gale-force W to NW’ly winds. Perhaps a wintry start to next week with strong NW or N’ly winds. Less cold after midweek as winds back to a lighter W’ly.
Be aware that the weather over north-west Europe – and especially around the Northern Isles – is part of an ever-changing and dynamic system. Therefore regard the ’10-Day Outlook’ as a guide only – there are times when any outlook going beyond about 36 to 48 hours is likely to prove
Always check the latest forecast from the UK Met Office before undertaking any weather-dependent activity.
All forecasts are for planning purposes only.
Neither Dave Wheeler, nor any employee of Fair Isle Weather Services, accepts any liability for the accuracy of this forecast.
Dave Wheeler MBE FRMetS
Shetland, ZE2 9JU
Telephone: +44 (0)1595760224
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