PDA Forum / Psion / July 2008

Here is a summary of the NWP output for noon (GMT) on Friday.
Issued 0512z, 28th July 2008

Saturday looks like being a wet (and cooler) day for much of the UK as a low
crosses Scotland. The low moves away during Sunday and sets the scene for a
more mobile spell of weather, with a NW/SE split regarding rain.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
High pressure lies to the NE, with light ESE'lies over the UK. Low pressure
moves up from the WSW tomorrow, leading to stronger easterlies for most.
Southerlies cover the UK on Wednesday as low pressure deepens to the west.
Thursday sees warm southerliers as low pressure persists to the west.

T+120 synopsis
http://85.214.49.20/pics/Rtavn12014.png /
http://85.214.49.20/pics/Rtavn1201.png
http://85.214.49.20/pics/Rukm1201.gif
http://85.214.49.20/pics/Recm1201.gif /
http://www.meteociel.fr/modeles/nogapse_cartes.php
The jetstream chart shows a trough over the UK, with the main thrust of the
jet passing to the south. At the 500hPa level there's an upper low over the
UK, while MetO keeps the low to the west instead. ECM brings upper
southerlies with a low to the west and GEM concurs.
At the surface GFS has low pressure west of Scotland, with a trough over the
Scottish border. To the north winds are easterlies, with WSW'lies elsewhere.
MetO has SW'lies over the UK with a shallow low to the west and ECM brings
southerlies and SSE'lies due to a deeper low to the west. SSW'lies cover the
UK with GEM, again with a low west of the UK.

Evolution to T+168
Day 6 with ECM shows low pressure over Scotland with SW'lies elsewhere.
There are further SW'lies on Sunday as a weak ridge moves eastwards.
GFS shows WSW'lies on day 6 with low pressure over Scotland. There's little
change on day 7.

Looking further afield
On day 8 with ECM SSW'lies cover the UK, due to a low to the west. There are
WSW'lies on day 9 as the low moves ENE'wards and on day 10 a col covers
Scotland and Northern Ireland, with a ridge over England and Wales.
A col covers the UK on day 8 with GFS. The col persists on day 9, but by dy
10 low pressure moves over England and Wales. Scotland remains under a col.

Ensemble analysis
(http://91.121.94.83/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=0&ville=L
ondres)
The ensembles show a mobile (but warm) "sine wave" pattern oevr the next
week to 10 days.