There's growing, if still tentative, signs now (bolstered further by today's EC Monthly on the heels of GloSea5, plus the EC 30d MJO outlook) for a likely change of type further into this month towards a more settled & colder flavour. The transitional period mid-month (post-MSLP rises to W) is tricky for models: may be transitory, but ditto any return to mobility thereafter looks potentially short-lived, ahead of something drier/chillier to close this winter.
From IF earlier this morning
All my banging on about the MJO may yet pay off.
Actually, I say that, but it has already made a huge difference to the projected strength of the ridge into the Arctic that leads to the U.S. cold shot and could allow for a mid-Atlantic ridge and sliding low combination mid-month (this being the tricky transitional period).
So the verification of MJO-led expectations has been good for the N. hem pattern as a whole, but unfortunately this has not yet worked out for the UK in terms of getting more than transitional, north-focused snow out of it. Sounds very typical doesn't it? Events in the stratosphere have not played ball and this is the main reason for our troubles mid-month. It could have been so much quicker and easier but when that second bout of warming came into view some 10 days ago, it became clear that there was a considerable risk things would not go well (it had to produce a split vortex to deliver the goods. No dice.).
Still plenty of indications, now being hinted at by Fergie, that the MJO will traverse 6/7/8 during the final 10 days of the month, which corresponds strongly to increased HP influence which then transfers to the N and NW of the UK. Only when the actual extremity of the resulting pattern becomes apparent will I know whether to be happy about that or not... in my books, it has to be something special to justify a delay to spring!
Edited by user
Tuesday, February 2, 2016 1:28:07 PM
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Reason: Not specified
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