Early Season Snow Cover
October snow cover and its extent in the northern hemisphere offers clues on how early winter across the USA may unfold in the coming months.
Of interest is snow cover over Siberia and portions of the high latitudes including the Arctic. The amount of depth of snow cover in the month of October can have a big impact on making cold air masses early in the winter season.
If snow cover is off to an early start in Siberia and portions of the high northern latitudes it could signal a cold and early start to winter. The graphic below shows the extent of snow cover as of October 7. As you can see, many areas of Siberia, Greenland and northern Canada already has snow cover. The shorter days and longer nights will likely keep that snow cover in place.
Already this fall, several shots of cold air and snow has invaded portions of the Rockies and Pacific Northwest.
In addition to snow cover, sea ice extent also has a big impact. As you can see in the graph below, after a big dip in Arctic ice extent, high latitude sea ice coverage has increased.
Ice extent this September was up over last year. The early October snow cover, increased ice extent and cooling Pacific waters (La Nina) all indicate some high chances for some shots of very air into the USA this winter season.