Posted by: splillo | February 18, 2012

Storminess and Futility records

Following up from the last few posts, the contiguous US (CONUS) is being affected by a stream of energy pouring onshore in the west and then amplifying over the center of the nation. The storm in formation in the south right now is the first of what will likely be a train of storms pounding the country over the next few weeks.

Why is this so? The storminess stems from something called the Madden Julian Oscillation (MJO) which is essentially a wave of enhanced vertical motion and moisture generating thunderstorm growth near the equator. The MJO has a period of about 45 days and can be tracked around the world, but is normally focused in the Indian Ocean and West Pacific. In the current case, it has propagated into the eastern Pacific and is now energizing the jet stream from the Pacific into the United States.

That's on the large scale. On a smaller scale, we're still staying dry in the Northeast this weekend as the storm is suppressed south of us. This is an impressive system though. A plume of moisture can be seen on water vapor imagery (below) from the Gulf of Mexico across the southern states. Severe weather and tornadoes have been reported from Louisiana to Georgia.

Also visible on this satellite image are the individual shortwaves at work. Notice the circulations in southern Manitoba and Nebraska. Both of these waves will be dropping into the southern system tonight and tomorrow, amplifying the storm. Any other winter, this could be a major snow storm for the east coast, but it just can't snow this year. The problem is another shortwave over the Great Lakes that will be keeping the storm on an east-northeast heading off the Mid Atlantic coast. Areas from Kentucky to Virginia could see a 5" to 10" snowfall tomorrow afternoon ... more snow than Boston has seen all winter.

Boston currently can account for 7.8" of snow this winter, a far cry from the 71.2" they boasted this time last year. The normal year-to-date is 29.8". Of particular interest now is what may be referred to as the futility record of snowfall. Boston's least snowy season on record was 1936-7 with 9.0" that winter.

So in the interest of record breaking, why not just head right on into spring and officially claim this winter to be the king of dead ratters! The problem is New England has a ways to go before declaring an end to the winter that never began. Climatologically speaking, Boston still has 12" to go. Normal snowfall in March is 8.1". And all that's needed is 1.3" to keep this winter out of the record books. The rest of the major sites in New England, like Hartford, Worcester, and Concord, are not as far down in the snowless ditch as Boston, owing to the historic October storm.

Any snow in sight for New England? ...Seems to be a theme of my posts thus far. As long as there are storms, there will be the possibility of snow here. The general pattern being advertised by the forecast models is a broad trough over the eastern two thirds of the nation, which can support fast moving light to moderate snow events here. We'll have to keep an eye on the train of storms over the next few weeks to see if anything can produce.