normal-mean, will become weakly Negative in the short-term.
"MARCH 2013" IN-RECAP.
NE-NAO - WEEKLY INDICE REVIEW, posted on
February 24, 2013, I stated:"This cycle combined with the predicted MJO highlight a threat for coastal storm development March 11-15...along with a continuation of below normal temperatures. The second half of March may moderate to above to well above normal temperatures briefly, but don't be caught off guard with Spring-fever-yet... for the end of March into the beginning of April will mark a return of wintery elements!"
While March 9-13 was certainly a blow-torch, which was seriously overlooked on my part due to no true sign of a significant pattern change... at the time the post was published. This is what I consider a "hiccup", in an overall threatening pattern.
It is, of course, no surprise that we returned to below to well below normal temperatures March 14-15... considering the overall longwave pattern did not undergo a major change.
As a result, the threatening mid-March pattern will be realized again with a coastal system that will effect New England March 18-19.. with a potential for accumulating snow over western & parts of northern New England, while southeastern New England will likely see
mixed-precipitation to rain. Temperatures will average colder than normal through March 20-21, due to the persistent -AO / -NAO influence. I did state that the second half of March may moderate to above to well above normal temperatures briefly... however this appears to be just another "hiccup" in the pattern again, with a moderation
in-advance of a significant cold frontal passage March 22-24.
Mid-to-Late March is when temperature averages significantly rise in the Northern Hemisphere, due to the natural "seasonal" change in the Earth's tilted axis
in-relation to it's orbit around the sun. This change, makes it more challanging for snowfall in New England... especially during the beginning of April, however other factors can still overwhelm the odds. The factors in-place that have strong potential of overwhelming the odds as we head toward late March:
1. Post Solar Maximum Winter - shows signs cyclically-speaking, of Blocking patterns being a predominant feature (-AO / -NAO) from late March through the beginning of April.
2. Madden Julian Oscillation (MJO) - Currently in Phase 6-7, forecasted by the GEFS to propagate through Phase 8-1... which encourages an overall
-EPO, -AO, -NAO Pattern.
3. Antarctic Oscillation (AAO) - Not a typo, this indice which has recently been in an overall Positive Phase... is forecasted to become very weakly Negative toward the end of March, the AAO acts in a similar manner as the AO in the Northern Hemisphere, especially during times of significant Height amplification.
To say that the period of March 25 to April 10 will be persistently below normal
in-temperature would be improbable, considering the time of year... however the factors combined strongly support below normal temperatures overall through the period. This period also highlights a continued risk of coastal storm development, considering the above said factors that will strongly influence the
500-millibar Height Pattern.