Saturday, February 9, 2013

Valentine's Day Potential Nor'easter

There is potential for another coastal storm in the Northeast on Valentine's Day.

Above is a 4-panel graphic forecast for the morning of February 12th. We see our storm system as a deep low pressure center in the eastern Rockies, about to eject into the Plains. The strength of the system is reflected in 500 millibar vorticity values in the top left panel. Reds indicate low pressure systems, purples show high pressure. Downstream from this storm, we are seeing some building of higher pressure in the Southeast, something that typically can drive storm systems further north than south. To me, the system wants to press south based on the mid atmospheric flow, but that can't happen unless dissipation of these higher pressures occurs in the Southeast. Considering how negative frictional torque values have also shifted north in response to the subtropical jet stream's northward movement, it would seem to me this system may be a bit too far south in this model's forecast.

Regardless, by Valentine's Day, the storm system has moved across the Plains, Midwest and Ohio Valley to arrive offshore the Northeast as a coastal storm. If this were to occur, another layer of accumulating snow would be put down on the same areas that are waking up today to nearly 40 inches of snow in some spots. The lack of high-latitude blocking over Greenland puts a concern out of how close to shore this system will be. If there is little blocking over that region, it is possible the models may slowly shift the storm more eastward with time. However, if that actually happens remains to be seen; my confidence is low on such a potential.

The same model forecast results in upwards of 6 inches of snow for many in the Mid-Atlantic and Northeast into New England. We are still a while away from this event, but it should be watched very closely. Valentine's Day has a reputation for having a major winter storm for some part of the nation.


1 comment:

John said...

Great forecast. Im in the baltimore area and missed out on the most recent blizzard. The models have this Valentine's day storm on us. So i hope it works out!

Bad news is,its supposed to be 44 degrees here on Valentine's day. Do you think there will be enough cold air?Keep us updated!