One strong weather barrier wey dey hold some of the coldest air for nature don break down temporarily, and e happen earlier for the year than normal. Disruption for this circulation, wey dem dey call polar vortex, dey often push very cold air from Arctic go lower latitudes. Experts never still sure how the current collapse go take show for everyday weather, but e be another sign say weather fit get rough for weeks and months wey dey come.
The polar vortex na band of upper-level winds wey dey wrap around Arctic Circle like dam. This circulation usually strong and stable, and e dey help keep the season coldest air locked near North Pole. But the winds fit weaken or even reverse course, and that fit start atmospheric chain reaction wey allow bitterly cold air spill south.
How the polar vortex break down dey determine kind weather wey fit follow. When upper-level winds dip southward inside troughs, dem fit cause brief spells of cold temperatures. These lobes of the polar vortex, as dem dey call them, common well well for normal winter. Sometimes the circulation fit splinter into smaller pieces. If the vortex be flowing river, the fragments be like leaves wey stuck for riverbank, and dem fit force extremely cold air to linger over same areas for days or weeks.
One such case make the phenomenon popular. A highly disrupted polar vortex for early 2015 send weeks-long burst of cold air over eastern United States. Chicago record its coldest February in nearly 140 years. For Lexington, Kentucky, temperatures bottom out at -18 degrees Fahrenheit, as subfreezing air dive reach Gulf of Mexico.
Seeing polar vortex breakdown this early for season no get precedent for historical record. Disruptions of this extent normally no dey happen until latter half of winter. Based on latest data, the circulation reversal begin on Tuesday, and computer model guidance expect am to last through Thursday.
Weather patterns dey take few weeks to respond to polar vortex disruption, if dem respond at all. Reliable forecasts only extend about 10 days into future, so we no fit know where for northern hemisphere cold air from Arctic fit spill. Experts still dey debate exact causes wey dey drive this polar vortex breakdown. The event add another problem to cool season wey another unprecedented event already dominate: the strongest El Niño on record. Historically warm sea surface temperatures for eastern Pacific Ocean don already affect conditions around the world, and this influence go only grow as winter months dey come.
