On Friday, Jan. 21, 2014, the Weather Channel christened winter storm Nika while it was still an embryo in the Pacific Ocean.
The storm is now bringing welcome rain to California, and is forecast to develop into yet another snow-sleet-freezing rain-maker from Texas to New England.
This will happen if Nika can negotiate safe passage over the formidable barrier of the Rocky Mountains.
The Effect of Mountains on Weather Systems
Weather in the mid-latitudes can, to a rough approximation, be attributed to the jet stream. The strongest jet stream winds are generally found over the greatest temperature gradient (difference in temperature) at the ground, and storms form on this ‘front.’
The Rocky Mountains of the United States reach into the jet stream — up to 14,000 feet. Traversing such an obstacle can be problematic for storms.
The Effect of the Rockies on Weather in the United States
In the winter, cold air pushes south out of Canada into the Great Plains and midwest. A good push sends the arctic air all the way to the Gulf of Mexico and the south Atlantic states. When warm, moist air from the Gulf of Mexico meets the arctic air in the southern plains, midwest, and east coast, the stage is set for storms: there is potential energy (temperature gradient) and moisture.
When a ripple in the jet stream, like the one responsible for Nika, interacts with these favorable conditions, a powerful storm can result — as long as the ripple doesn’t get lost in the wilderness of the mountains.
Nika’s Likely Path
When low pressure enters the mountains, it tends to disappear and re-develop on the lee side, most commonly in Colorado, but often farther south. Nika is expected to re-form in Texas and New Mexico and head east-northeast. The cold air to the north will assure that the precipitation is all snow away from the frontal boundary and rain will fall to the south.
Most importantly, there could be freezing rain right along the 32 degree line. Right now, freezing rain seems most likely in Oklahoma and Arkansas on Tuesday and from Pennsylvania through southern New England on Wednesday.
Nika could be a prolific snowmaker just north of the frontal boundary in Illinois, Indiana, Ohio, Pennsylvania, New York, and central and northern New England. Some areas could receive up to a foot of snow.
Could Nika Be the Last? Please!
Not likely. At this time Nika looks like a fast-mover that will clear the New England area by Wednesday night. However another storm is indicated for the weekend. This one, if it becomes worthy of a name, will be called Orion. Current computer forecasts indicate that Orion could develop into a strong nor’easter when it reaches the Atlantic Coast.
This could convert some of the potential energy that lies along the frontal boundary to kinetic energy of wind, and dissipate it into the ground as heat, and would likely bring about at least a pause in the seemingly unending parade of storms. Let it be so!