April 15th 08, 03:33 PM
posted to uk.sci.weather
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First recorded activity by Weather-Banter: Mar 2008
Posts: 10,601
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Spring coming?
On Apr 14, 12:56*pm, Dawlish wrote:
On Apr 13, 9:14*am, Dawlish wrote:
On Apr 11, 9:28*am, Dawlish wrote:
On Apr 10, 9:39*am, Dawlish wrote:
On Apr 9, 12:27*pm, Dawlish wrote:
On Apr 9, 11:55*am, Bridge of Sighs wrote:
On Apr 9, 9:40*am, Dawlish wrote:
On Apr 9, 9:31*am, Dawlish wrote:
On Apr 8, 1:14*pm, Dawlish wrote:
Well, there you go.The possible warmth has continued for 5 runs, I can
now be 75-80% certain of this:
By 18th April at T240, the effects of the first warm plume of the year
will be being felt in Southern England. Temperatures on the 17th and
18th of April will peak above 18C and may well be higher. Winds around
this time will be from a Southerly quadrant and the air will have had
its source in North Africa. This air could well be unstable enough to
bring the possibility of heavy, perhaps thundery showers. If the
showers stay away, Southern England, at least, will have some
pleasant, warm conditions for April.
It can never be a higher confidence forecast than 75-80%, as my
success from the past is about 78%. It's not a certain forecast, as
certainty doesn't come in to forecasting. See how it goes.
Paul
The gfs develops the North African plume further this morning, with
some pretty scorching spring weather over Spain (El Horno could be
fired up early!) on the 18th but this run terminates the Northerly
extent of its influence in the Gironde and leaves us in cool North-
Westerlies. That could change over the next couple of days, but if
this forecast joins the 20-25% of complete and utter faliiures - oh
well! So be it! It happens. It's still a lot of fun trying. My
forecast of a Northerly plunge and a cold Easter in 2007 wasn't the
best *)) , but there have been 42 successes over the last couple of
years! Plumes seem to be very hard to correctly forecast at 10 days.
They require such specific synoptics to reach the UK. The gfs is still
wrestling with the position of that Atlantic Low sitting off Iberia on
the 00z.
http://www.wetterzentrale.de/pics/Rtavn2282.png
This run puts it further South than it was when I made the forecast
yesterday. For the plume to reach the UK, it needs to be several
hundred miles further North. It'll be interesting watching it.
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