2016-17 Arctic cyclone season

The 2016-17 Arctic cyclone season is a current event in the Arctic Ocean basin. It will be the second season with named storms. The season will officially begin on November 1, 2016 and end on January 7, 2017. Storms are a part of this season if they form between June 1, 2016 and May 31, 2017. However, polar cyclone formation is possible at any time of year, although extremely rare during the summer months. This season started exceptionally early with the formation of Subpolar Storm Advent in late June, which later became an extremely rare offseason catastrophic polar cyclone. Three other cyclones formed before the official start of the season: Subpolar Depression Two, Polar Storm Bow and Polar Cyclone Carol.

Seasonal Forecasts
On April 20, 2016, the BNWC released their early forecast for the season, featuring slightly below-average activity due to a warmer North Atlantic than the previous year, which could suppress the cyclones from becoming polar. Their prediction consisted of 14 named storms, 7 polar cyclones, and 3 major polar cyclones. However, due to the formation of Polar Cyclone Advent and better conditions than originally forecast, the BNWC revised their numbers upwards on August 4, predicting 16 named storms, 9 polar cyclones, and 4 major polar cyclones, which included Advent. On September 20, six centers released their predictions for the season; the Garfield International Hurricane Center (GIHC), The Keranique Meteorological Center (KMC), the HurricaneOdile Weather Center (HOWC), JD Meteorological Center (JDMC), Floyd Meteorological Center (FMC) and Akio Hypothetical Hurricane Center (AHHC), which all forecast a slightly above average to above average season, citing favorable conditions.

Polar Cyclone Advent
On June 24, the Bob Nekaro Weather Center began monitoring an extratropical cyclone in the northern subtropical Atlantic for the development of subpolar or polar characteristics as it tracked over cooler waters in a few days. Early on June 27, the cyclone began developing polar characteristics sooner than originally forecast due to cool waters, and later that same day, the cyclone developed into Subpolar Storm Advent. Early the next day, Advent became fully polar and became the first June polar cyclone on record. Slight weakening took place in the coming hours, before Advent acquired 105 mph winds early on June 29. Early that same day Advent strengthened into a major polar cyclone. At 18:00 UTC on June 29, Advent reached maximum sustained winds of 155 mph, nearly reaching catastrophic polar cyclone status. A weakening trend began later that night due to wind shear from nearby Polar Vortex Abby. Around 16:00 UTC on June 30, Advent made landfall over Greenland with maximum sustained winds of 85 mph as a weak polar cyclone. At 21:00 UTC that same day, Advent weakened below polar cyclone status as it moved over Greenland. On July 1, while weakening, Advent emerged into the Baffin Bay as a polar storm. Late that same day Advent weakened to a polar depression. Advent then briefly regained polar storm status in a blowup of convection near the center, but the blow-up was short lived as Advent degenerated into a remnant low on July 2 in northern Canada. The impact of Advent was minimal.

Subpolar Depression Two
On September 10, the BNWC began monitoring a persistent area of snow showers in the western Baffin Bay. The next day, advisories were initiated on Subpolar Depression Two when a well-defined circulation was found after an ASCAT pass. Late on September 11, Two strengthened slightly and the BNWC said that strengthening into a subpolar storm was possible. However, this never materialized, and Two made landfall late the next day around 8:00 PM CDT in a sparsely populated area of Canada as a subpolar depression with maximum sustained winds of 35 mph and a minimum pressure of 1006 millibars. After landfall, the subpolar depression began to weaken. The circulation of the subpolar depression then dissipated around 09:00 UTC on September 13.

Polar Storm Bow
On October 4, the BNWC began monitoring the southwestern Hudson Bay for possible polar cyclone development over the coming days. At 03:00 UTC on October 9, the system became sufficiently well defined to be classified as Polar Depression Three. 12 hours later, it was upgraded to Polar Storm Bow. Bow strengthened to a strong polar storm on October 14, and peaked with maximum sustained winds of 65 mph. Bow made landfall at this intensity in the northwestern Hudson Bay region of Canada, causing no reported damage or deaths. Bow dissipated early on October 16.

Polar Cyclone Carol
On October 28, a polar wave developed into Polar Depression Four at 21:00 UTC north of Newfoundland. Six hours later, the depression strengthened into Polar Storm Carol. 24 hours after being named at 03:00 UTC on October 30, Carol strengthened into the second polar cyclone of the season.

Pre-Season
On June 27, an extratropical cyclone developed into Subpolar Storm Advent east of Newfoundland. Advent later became fully polar and strengthened into a catastrophic polar cyclone two days later after undergoing rapid intensification, becoming the strongest off-season polar cyclone in history. Less than two months later on September 11, Subpolar Depression Two formed in the western Baffin Bay, which made landfall in a sparsely populated area of Canada with minimal impact. Two dissipated on September 13. Early on October 9, Polar Depression Three formed in the southwestern Baffin Bay from a polar wave; Three later strengthened into Polar Storm Bow 12 hours later. Bow peaked as a strong polar storm with maximum sustained winds of 65 mph, and made landfall at this intensity in Nunavut late on October 14. On October 28, Polar Depression Four formed, later becoming Polar Cyclone Carol.

The Accumulated Cyclone Energy (ACE) for the 2016-17 Arctic cyclone season, as of Two's final advisory, is 14.4375 units.