Monday, March 9, 2015

Monday Morning Weather Discussion: Spring Weather Leads to Weekend Trouble

Good morning everyone. It is going to be an excellent week in terms of temperatures. Many areas wil be in the 40's and 50's. Be sure to enjoy this while it lasts because I am predicting that the second half of March will not be pleasant.  In fact I am gaining confidence that we will have weather issues this weekend let me explain why.

  • Very active sub tropical jet emerges out of the Gulf of Mexico this week.
  • As this jet stream sprays moisture into the east a stubborn Canadian high pressure system will develop over the Northeast locking on cold air.
Image below shows this..

It is important to not underestimate high pressure systems. More times than not this winter they have ended up being stronger than modeled. Recent trends over the weekend have pointed to this high pressure system being a real threat.

So whats the bottom line?

Areas from Phili northward can see winter precipitation from this system. I would expect that it ends up being snow/ice to rain say from Phili to NYC but in Southern New England this can be a snowstorm on Saturday. I am basing this on model trends. 

For the more advanced end of things, the upper air pattern supports this high pressure being held in place due to confluence over the east. Confluence can be seen by the height lines converging along an axis.

Everyone is going to think I am crazy as they experience a taste of spring this week but remember I warned you. 

Moving into next week the pattern gets only more interesting as we have a negative NAO, negative AO, Positive PNA, and Negative EPO develop. All these variables mean cold and stormy end to March..

Enjoy the warm weather! I will have time tonight to go into more detail on all of this. 

1 comment:

  1. Yea, I see that Joe Bastardi hints on his freebie clips at a sudden strat warming event coming up. Which corresponds with the ensemble AO forecasts heading back to zero and maybe into negative territory in the 2nd half of March. Which means, I believe, that below-freezing air can still get pretty far south, including northern NJ, especially at higher altitudes. PNA model runs pretty clearly going back to positive. NAO certainly seems headed out of its present strong + zone, hard to say if it goes neg. Haven't seen much on the EPO lately, still waiting for the NOAA supercomputer to update that 4-panel chart (something about a power issue last week). And way out on the fringes, the MJO is clearly in 6 zone, but the March 6 discussion sez that MJO could wander back into zone 7 in the 2nd half of March, which contributes to troughs in eastern N. America. So I'm definitely ready for a few more winter-ish events, although the 40-day trend (1/26 to 3/7) of frigid cold / slight warmup / snow / repeat is probably over. As to this weekend, even the good old conservative NWS is currently using the S-word (along with "chance of") in its Fri Night / Sat / Sat Night forecast for western Essex. GFS sees a fair amount of mixed precip, CMC maybe just a bit, Euro supposedly keeps it further north. Ain't over till it's over. But once it finally is . . . wonder if the Atlantic tropical storm season is going to be quiet again. Andrew at Weather Centre talking about El Nino chances increasing into summer and fall (although he's not yet buying it). Which would imply possibly another quiet season (in the Atlantic, but not in the Pacific)? But Andrew also talks about Caribbean water temps being above normal. Something to watch over the next 6 mos. Jim G