Rhianna McCarte, 30, joins her neighbors to dig out their cars in Alexandria, Va., Sunday, Jan. 24, 2016. Millions of Americans were preparing to dig themselves out Sunday after a mammoth blizzard with hurricane-force winds and record-setting snowfall brought much of the East Coast to an icy standstill. (AP Photo/Cliff Owen)
Photograph by Cliff Owen — AP
Punxsutawney Phil may have blown it this year with his prediction of an early spring in the United States.
The legend is that if the Pennsylvania groundhog sees his shadow upon emerging from his burrow each Feb. 2, Americans can expect six more weeks of winter.
He did not see his shadow on Tuesday, suggesting that winter is soon to be over. But the atmosphere might beg to differ as multiple signs are beginning to appear that extreme cold is quite possible well into March.
Several key ingredients to the recipe for a harsher end to U.S. winter will be emerging in the coming weeks, with frigid effects expected to begin as early as next week. However, in order for the cold to sustain in the longer term, variables will need to work in tandem to enhance wintry conditions. If they are misaligned, warnings of extreme cold could be rendered as empty threats after all is said and done.
Although the overall trend for the next six weeks is not overwhelmingly cold, warmth is not expected to dominate as it did in December, owing partially to an upcoming shift in the general global weather pattern away from El Nino-like conditions.
U.S. energy markets, which are still hungry for a turnaround in demand following a warm autumn and start to winter, could see some considerable price action if a colder forecast lines up and sticks around.
All things considered, the forecast for the remainder of winter is quite tricky. All of the cards necessary for a brutal end to winter will be out on the table, but it will all depend on whether the atmosphere plays them in the correct order.
One of the main factors reducing the chances of warm domination for the rest of winter is that El Nino’s influence, which often leads to warmer U.S. winters, is fading.
Although El Nino is still strong, the atmosphere will be less responsive to this pattern moving forward. This is due to the expected slowdown of the atmosphere’s spin relative to Earth’s spin, which will weaken the flow of the warm, subtropical jet stream into the United States.
A near-record Sudden Stratospheric Warming (SSW) event currently in the works will also create more opportunity for cold outbreaks in the long run. Strong, rapid warming in the stratosphere is highly linked to subsequent dives in the Arctic Oscillation (AO), which if sufficiently negative, can produce frigid conditions across the Northern Hemisphere.
Both SSW and the AO have close ties with the polar vortex. SSW events tend to disrupt the polar vortex, sending it off its axis and into the mid-latitudes, and often skewing AO to the negative side in the process.
The timing of a U.S. cold outbreak stemming from upcoming SSW is very difficult to pinpoint, but the broad time frame would be late February into early March. Impacts could also be prolonged based on the intensity of the event.
But a deep freeze is also looming in the short term because the polar vortex is already destabilized. Forecast models have been baking in a flip to negative AO beginning next week, when chilly air will begin to build east of the Rocky Mountains. This cold outbreak could culminate with what may be one of the coldest Valentine’s Day and Presidents’ Days on record from the Midwest through the Northeast.
Snow cover also adds to the potential chill factor as it generally lowers air temperatures when present. This is because snow reflects much of the sun’s energy that the ground could have otherwise absorbed.
This week’s snowstorm generously replenished snow pack across much of the Plains and Upper Midwest, and since the snow is unexpected to melt anytime soon, this could amplify the intensity of next week’s cold outbreak in the region.
Additionally, much of the Midwestern and Northeastern United States will experience light to moderate snow showers at various points over the next week, subjecting an even larger area to the possibility of temperatures colder than currently expected by next weekend.
To add insult to potential injury, another nor’easter cannot be ruled out for late next week, something U.S. East Coast residents do not want to hear after digging out from the late January nor’easter storm dubbed “Jonas.”
The upper air pattern that sets up next week will create an environment highly conducive to nor’easters. High pressure will persist in the Northwest, leaving all points east of the Rockies subject to frequent storm activity as a result of the dominant low pressure.
This does not necessarily guarantee another massive storm for folks along the U.S. Eastern Seaboard, but if the triggers are present and the positioning is just right, nor’easter formation is quite realistic and would happen quickly.
One of the most important triggers is the ascent of the AO once it bottoms out next week. The weakening of an AO-negative regime often coincides with the strengthening of a deep low-pressure trough in the US, if present, as it provides storms with that extra “oomph” that can turn ordinary storms into extraordinary ones.
As such, it will be important to watch the development of the low pressure system next week and its potential alignment with the AO pattern. If this scenario were to verify, the East Coast might be snowed in again for the second time this winter and Phil’s credibility as a meteorologist may take a hit.