Buresh Blog: HOT September!.... October averages.... Arctic seasonal ice melt minimum reached

Sept. 27, 2018 — "Talking the Tropics With Mike" - updated every single day during the hurricane season.

We've endured one of the hottest September's on record in Jacksonville.  The charts below are as of Sept. 26th.  But perhaps most remarkable is that we have had no nights below 70 degrees for the entire month - something that has not happened in the last 30+ years!  This September will manage to rival August as the hottest month of the year & was hotter than June & July with nearly as many 90 degree days as July!  The culprit has been a semi-permanent upper level high pressure near or over the Southeast U.S.  Generally sinking air under this kind of weather system results in above avg. temps. & - usually - drier conditions as well.

So we turn the calendars to October & should expect cooler temps. :) .... averages at JIA:

Low / High - 1st: 66 / 84..... 31st: 55 / 77

Rainfall: 3.93"

Sunrise / Sunset - 1st - 7:20am / 7:12pm..... 31st - 7:40am / 6:40pm - lose 52 minutes of daylight.

And as we exit from summer into fall, the arctic sea ice has reached its minimum & looks like it will go down as the 6th greatest ice melt on record - an ongoing trend over the last 20-30+ years or so.

From NEEF - By Sarah Blount:

With the  release of the National Snow and Ice Data Center's analysis of 2018's conditions for sea ice minimum, it's a good time to take a look at the role this ice plays in the larger Arctic ecosystem, and how different marine mammals rely on this fluctuating resource.

Polar bears

Polar bears spend most of their time on sea ice, using these floating platforms as their base of operations for hunting and feeding on ringed seals, their primary prey, as well as a habitat to look for potential mates and eventually breed. Sea ice is also used to help polar bears get from point A to point B—in this manner, the sea ice serves as their transportation infrastructure, helping polar bears move inland to their terrestrial denning areas, and to make other long-distance movements.

Arctic ringed seals

The smallest seal in the Arctic, the ringed seal uses sea ice for shelter, giving birth (pupping), and for resting. Their thick claws can create and maintain breathing holes in the ice, allowing the seals to remain in the water beneath the ice for extended periods of time. Atop these breathing holes the female seals may construct a lair in the ice, which is used for resting, as well as pupping and nursing their young. Outside of the lair, the seals take advantage of the surface of the sea ice to bask in the sun while they complete their molt.

Walruses

Like their pinniped brethren the ringed seals, walruses are also highly dependent on sea ice for birthing and haul-out space (when the marine mammals will emerge from the water to rest after feeding bouts), with birthing concentrated in the late spring, and haul-out occurring throughout much of the year. The walruses also rely on sea ice as a source of stability and safety during storms, taking refuge on the floating platforms for protection from the roiling seas.

With these dependencies in mind, take a look at the trends scientists are observing in arctic sea ice cover: Diminishing Arctic Sea Ice.

Sources:

• Alaska Regional Office, Marine Mammals Management Office. n.d. Environmental Assessment: Endangered Species Act 4(d) Regulations for Threatened Polar Bears. Anchorage: US Fish and Wildlife Service. 
• Kovacs, K. M., P. Lemons, J. G. MacCracken, C. Lydersen. 2015. Walruses in a Time of Climate Change [in Arctic Report Card 2015]. NOAA.
• NOAA Fisheries. 2016. "Ringed Seal (Phoca hispida)." NOAA. Accessed September 27.
• NOAA Fisheries, Alaska Region. 2014. Arctic Ringed Seal Critical Habitat: Questions & Answers. National Marine Fisheries Service, NOAA.

Florence was one of the most devastating hurricanes on record - from a water standpoint - for the Carolina's.  The tropical cyclone was not an easy one to forecast & - for many - it will be surprising to learn that the American GFS model outperformed the often-ballyhooed European forecast model.  In an article in the Washington Post, the GFS model is the clear "winner".  None of the models did very well with intensity - too strong up to landfall - but the GFS won this battle as well.  However, the FV3 GFS model - which is a planned replacement for the GFS - did not outperform the older GFS though did still manage to have smaller errors than the European model.  All of the global forecast models struggled with the positioning & especially strength of the upper level high pressure ridge from the Central U.S. to the NW Atlantic.  That single synoptic scale weather system likely caused the greatest headaches (errors) for the forecast models.

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