Meteorological spring may start March 1st, but it looks like it will be a sprint to the arbitrary winter finish line to round out the month of February across the Great Lakes and Ohio Valley.
The current pattern is a quiet one across the region. Due to the relatively fast flow and weak –NAO, we are seeing seasonably cool conditions temperature wise and a weekend storm will at best graze the southern Ohio Valley, where winter storm watches are posted.
However, the –NAO will be a transient one as an upper level trough expands across the arctic and north Atlantic, and a significant polar vortex develops to the west of Alaska. This will result in ridging off the west coast of the US and a northwest flow into the central US, along with a building southeast ridge due to the +NAO that will soon develop. This will put the Great Lakes and Ohio Valley into a battle zone and encourage a stormier pattern to round out the month.
The GFS ensembles show this transition well by the middle of this upcoming week. This will result in a series of relatively weak low pressure systems tracking across the Great Lakes and upper Ohio Valley Monday-Friday. The models have not timed these systems out well yet, but the general consensus is for snow across the upper lakes to start the week and a cold rain across the rest of the region, with snow becoming more likely with each system in all areas except for perhaps south of the Ohio River by Thursday and Friday. No major snows are expected, just nuisance events. Although the pattern will turn cooler by the weekend, true arctic air is not yet expected.
As we head into next weekend, the most extreme amplification will occur. A northerly flow will develop into the Rockies and it appears that some tropical moisture will come into play. Models are playing around with a major storm tracking somewhere east of the Rockies to begin next week. We are still over a week out and well phased storms have not been the trend all winter, so it’s tough to tell where any storm will track or how strong it will be. The GFS ensembles from last night show a wide variety of solutions, ranging from a weak storm that tracks across the Ohio Valley to a strong storm that tracks into the western lakes. Needless to say, we will have our eyes on this in the coming days.
Last night’s GFS ensemble members: