martinastro
Martin Mc Kenna
Global Moderator
Hero Member
Posts: 5182
Maghera, N. Ireland
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« on: November 12, 2009, 04:18:31 pm » |
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UKww Weather Warning for Heavy rain and severe gale to storm-force winds
Issued Thursday 12/11/2009 1400BST
Areas affected: Wales, England (with emphasis south of a line Preston-Newcastle-upon-Tyne)
Valid from: 1400GMT Thurs 12th November - 0300GMT Sun 15th November
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General evolution:
An area of low pressure with a centre at 970mb 300 miles west of Galway at 1200 Thursday will become complex with several centres in the following 24 hours. One such centre, 980mb, 250 miles SW of co. Kerry at 1200 Friday, comes under the left exit region of a powerful jetstreak Friday into Saturday morning with the result that it deepens to 970mb as it approaches the SW UK, expected just off St Davids Head at 1200 Saturday and clearing into the North Sea early on Sunday. Associated fronts followed by showery troughs will alternate over the UK during the forecast period.
Forecast:
Intense rainfall associated with the first set of fronts, already into SW England, N Ireland and W Wales, will continue to spread N and E through the rest of Thursday. Some very heavy bursts of rain are to be expected with strong and squally winds possible. Rain totals of up to an inch (25mm) are possible and due to the intensity of the rain there could be flooding problems caused by rapid runoff from already saturated ground. Clearer conditions but with squally showers, thundery in places with hail, will follow on Thursday evening and will last until Friday morning when the next frontal rainbands will push up from the south giving a very wet day indeed for southern England and Wales, the rain again very heavy and squally at times. 2-3 inches (50-75mm) can be expected, with the highest totals likely over the Welsh mountains and the moors of the SW: following on from Thursday's rain means that flooding is almost inevitable. This rain clears overnight into Saturday but is replaced by heavy showers and most significantly by severe gale to storm-force winds moving in from the SW and affecting S & W coasts, with gales or severe gales affecting inland S England and Wales. Saturated ground makes trees easier to blow over, and the highest gusts (70-80mph, the latter especially associated with heavier showers) will be sufficient to topple trees, break off branches and cause structural damage. This threat, in addition to flooding and leaves blown in quantity onto the roads, spells out a difficult and at times dangerous period for road users, with some disruption expected.
Issued by JSM for UKww, 1400GMT 12/11/2009
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