blizzardof96

If I was doing a QPF blend at this stage, I would probably do a Probability Matched Mean of the following: 12z EPS mean : 12z ECMWF : 12z GEM : 12z UKMET

Majority of GEFS tracks are south of the Ohio River whereas EPS has majority of tracks north of the river. GEFS looks off in my opinion.

Positioning of the TPV over Manitoba is going to be critical. At this time, the GFS & ECMWF do not agree on its positioning. GFS has the vortex further south, which prevents the southern vort from amplifying. My instinct is that the GFS is too extreme with amplification of the northern stream feature.

Very rare to have a system that has the potential to dump significant snowfall on Chicago, Detroit, Toronto and NYC. Going to be watching the system closely over the next few model cycles.

12z HRDPS snow and sleet accumulations through 12z (7AM) tomorrow: SNOW SLEET

Wishing everybody good luck from the Great White North. Get out and enjoy, if you can. Let it snow.

With the weakening +IOD, we are starting to see changes in the distribution of convection in the tropics. The EPS is shifting the strongest uplift from W IO to S America. This will have major implications on the upper air pattern in my opinion.

Quick video I created which addresses the storm threat:

Will be traveling Toronto to NYC Thursday night into Friday morning. Passing through Buffalo—> Binghamton—>Scranton. Will likely encounter first snowfall of the season en-route.

Looking back a bit to gain some perspective. In chronological order: 1) -ve mountain torque in place at beginning of November 2) +AAM tendency ~35N through late november (circled in blue) 3)Ridges dominate NA (through mid latitudes) in December with MJO over IO/E HEM Now: 4)Positive MT and MJO in phases 6--7 5)Beginning of southward momentum transport ~35N (circled), increasing tropical +AAM, increasing global +AAM Future(Mid Jan onwards) 6) -EPO, +global AAM, troughiness dominates?

Besides playing a role in the SSW, the +EAMT spike and strong MJO pulse are helping increase +AAM/westerly momentum between 30S--30N. This is visible on the relative AAM tendency charts. There is also -AAM tendency north of 30N which is opposite of what we saw in mid-late november. What usually follows is a pattern change with more troughiness in the mid-latitudes. It will take some time but things seem to be on track ATM for a pattern shift.

EAMT hits highest peak so far this cold season. 2 standard deviations above normal.

You can see the downwelling atmospheric Kelvin Wave propagating just out in front of the MJO wave. What this may do is destructively interfere with rising motion from the MJO in phases 6/7 on the RMM plots. So the MJO wave is still there but amplitude decreases on RMM. Another possibility is that the wave dies off... that seems unlikely if you loop the map below on Mike Ventrices site.

Thanks guys. It looks like the statistical MJO models have all bases covered. Going to the GEFS or ECM won't provide much help at the moment either. It'll be a tough time for the long range models until they resolve this wave.

Hey Guys. Just came across this forum a few days ago... hoping to contribute from time to time in the future! I'm Severe Weather Blog on twitter under the same handle(@blizzardof96). Cheers.