Monday, January 30, 2012

**February 2-6 Potential Significant Snowfall NEW Discussion**

12z GFS total snowfall
The 12z GFS has taken a turn for the disgusting today. It's looking like the GFS is projecting the storm system to become a separate storm of its own and move north and obliterate the Nebraska, Dakotas region.
As you all know, the +PNA and Strong Phase 6 MJO will be contributing to the eventual track and effects of this storm system. Using those major indices, I think this 12z GFS is garbage. Take a look at the ensembles.

12z GFS ENS Hour 120
12z GFS ENS Hour 132
12z GFS ENS Hour 144
To me, this is a much more acceptable solution. The GFS Ensembles are following a strong +PNA lead, whereas the 12z GFS acts like the jet stream shoots north after curving around the +PNA ridge. A +PNA actually takes the storm along the South and takes it up the East Coast. However, a Phase 6 MJO influences the heaviest precipitation into the Lower Great Lakes and interior Midwest. That would land the jet stream in a format very similar to what these 12z GFS Ensembles are showing.

The ECMWF takes a track that in my eyes looks like it takes a more predominantly +PNA track with maybe a slight MJO influence. Here's the ECMWF vs. the ECMWF Ensembles.

12z ECMWF Hour 120
12z ECMWF ENS Hour 120
The ECMWF Ensembles push the storm further north, but also push the warm air northward as well. In the process, the storm looks to be a tad weaker. However, individual ECMWF ensembles may show something else- we do not have access to those individual members, though.

HPC Day 4 Forecast
HPC Day 5 Forecast
The HPC goes along with the ECMWF/GFS Ensemble groups, much to my liking. Personally, the 12z GFS is one to be thrown out. I don't see that solution per the current trends of the teleconnections.

**A side note: Tonight's 0z model runs and tomorrow's 12z model runs will be ones to watch, as they will contain sampling (observation) data from inside the storm-to-be. You can tell the NOAA is watching this storm, because 12z observation data injected from a storm-to-be winter flight is rare.
By the way, the data is gathered from special airplane flights that drop items that record observations in the atmosphere. these observations are injected into the models and thus help solidify their solutions for those runs in that suite (0z or 12z).

Right now, I do think that the ECMWF/ECMWF ENS are onto something, as is the GFS ENS. I believe that the GFS ENS are banking on a stronger MJO than the ECMWF ENS are, which can be settled as the date for the storm approaches. I am going to go with a ECMWF ENS/GFS ENS blend, as again- group consensus' are better for me than models themselves.
Something I have discovered is that the ECMWF indeed keeps the MJO in Phases 6-7 weaker than the NCEP for the storm timeframe. That said, I think that the stickler for the models will be the MJO strength, as both ensemble groups from the ECMWF/GFS keep the PNA at relatively similar strengths.

I am thinking that the storm will affect the Ohio Valley and take the ECMWF Ensemble direction, where it may eventually hit the Northeast. The NAO will be an interesting piece to watch, as the models are not particularly certain on its fate during the storm.
Any questions may be asked below.


*Update on February 2-6 Snowstorm at 4:00 PM CST Today*

We will be updating on the potential February 2-6 winter storm at 4:00 PM CST this afternoon.