After the first glance at the overnight EPS I was about to call time of death on this crapfest of a winter. The setup at this point probably argues for us to see everything pass to our west and north short of great timing and a lot of luck. Then I looked a little harder into why we were seeing such a deterioration in the pattern from the great look we were seeing just a few days ago. And I found that maybe...JUST MAYBE... we weren't quite SOL yet.
The top image is EPS day 10 from 2 days ago. As you can see what we have is the PV in northern Canada interacting with the 50/50 low with a pulse/wave riding underneath the PV giving us the trough setup moving into the Midwest. This PV setup at this time, with it being so far north as well as interacting with the 50/50 probably argues strongly against seeing the trough in the east from digging far enough south to allow any northern stream energy to pass underneath us. Now compare to the next image which shows the overnight run at day 8.
Now look at the differences we are seeing up top. We are now seeing a disconnect between the PV in northern Canada, which has shifted westward somewhat, and the 50/50 which is coming in stronger because of this lack of interaction. What is causing this is the much stronger west based blocking in Greenland that is extending down towards ridging in southeastern Canada. This is effectively blocking the pulse wave that we have riding along the southern portions of the PV. We can see the effect as that wave very noticeable starts to lengthen and extend to the southeast. Now look at what the downstream implications are.
Now we look 1 1/2 days later. This is the day 11.5 of the run from 2 days ago. As you can see we never had a true disconnect between the PV in northern Canada and the 50/50. Thus we have a weak 50/50 feature as well the trough in the east being broad based and shallow due to the PV setup and the fact that it is so far north. There is not much fluidity in this look in regards to the eastern trough and getting the dig at which we need to see.
This is day 9.5 of the overnight run. We still see a total disconnect of the northern Canada PV with the 50/50. This lack of interaction has allowed the 50/50 as well as the ridging into Greenland to remain much stronger allowing for much better blocking. We also now see that the wave riding along the southern edge of the PV has been forced southeastward and detaching due to this blocking so that we shortly see a distinct PV lobe rotating just north of the lakes. This look shows better promise and flexibility then what we were seeing 2 days ago.
So what does all this mean? Well the look 2 days ago was a fairly rigid look that depended more so on the whimsy of the PV placement in northern Canada. This PV placement, with it being so far north argued against seeing this eastern trough dig substantially into the US. The fact we also saw continual interaction between the PV and the 50/50 also argued for a broad flat trough in the east. All in all, a look that probably favored any northern stream energy to pass well to our north without any amplification until it was well north and east of our area.
Now the setup being shown overnight isn't what I would consider a great look by far, but it actually gives me a little hope. We preferably want to see a sharper, deeper trough that would allow any NS energy to pass underneath us and the EPS now shows the possibility (GEFS also seems to be moving towards the EPS in this setup). With a distinct PV lobe we would no longer be depending on the PV setup in northern Canada, which was a fairly rigid setup without much play, as much as we are now depending on the lobe just north of the lakes which has a great deal more flexibility. Now here is where I see the possibilities. We have seen over the last several days of runs that the blocking in Greenland has become much stronger and further west based to where we now see ridging between the PV and the 50/50 which in turn is inducing a PV lobe to break off because of this blocking. Now let us just suppose we continue to see a strengthening of this blocking over subsequent runs. What that would most likely do is to then force that PV lobe farther south and/or west dragging the eastern trough along with it. A shift of 200/300 miles with that lobe actually would be a great look for the east coast. With a sharper, deeper trough situated down through the lakes, west based -NAO and a 50/50 the setup would argue for the possibility of northern stream energy Miller b'ing off the coast. Now we normally don't do well with Miller b's but that doesn't mean we can't cash out with an inch or two as that northern stream energy passes underneath us. And who knows, get that pv lobe to drop a little farther south....