Tuesday, 29 January 2013

MJO, Indicies Dictate Upcoming Pattern

It looks like we will see a cold shot for the first 5 days of feb with a train of clippers moving through. The MJO will head into a weak phase 1 after this which should bring some moderation into the east. Further down the road the pattern has the potential to be interesting with a more active STJ and transient pattern as the MJO progresses quickly through several phases. This means that we will see a more progressive and changeable weather pattern which will make it difficult to build a large snow cover in february. The mean storm track will shift around in the february 6-10th time period as well. Positioning of the blocking will be key. If we can see it set up stronger and further NW then we can see troughiness in the east. I am still not convinced just yet that this will occur with the very positive GWO, changeable MJO and weakening SSW event.
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I think the NAO will stay neutral to positive allowing for a further inland storm track and neutral to slightly positive PNA. The PNA will be key. If it trends positive after the initial cold shot(feb 1-5) then the storm track will shift to the east coast with the trough over the great lakes. This would set up a cold and dry pattern in the lakes but if the PNA trends neutral the mean trough shifts west allowing for more lakes cutters/apps runners if the STJ can get involved. The MJO supports the latter as the trough pulls back into the plains from the 6th of february onwards and i agree with this. The big question remains where you set up in relation to the BZ and each individual storm track to see if we can cash in on snow similar to late december fro many. The MJO will re-amplify in phases 2 and 3 which should open up a window for cold and storminess from the 10th-17th of february. 
MJO phase 8 in feb lines up with the first cold shot to start off feb. In phase 1 notice the trough pulling back west:
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Phase 2 and 3 brings the cold back in but in a progressive manor as the MJO moves quickly and a lack of blocking sets up. After the 25th of february the MJO will go unfavourable and SSW effects will wear off which should allow for a warming trend and a spring preview.
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