While the calendar says “spring” and the map shows “tropics”, the National Weather Service in Honolulu, Hawaii has issued Winter Storm Watches for heavy snow for portions of the Big Island of Hawaii. The weather service warns that a half foot or more of snow could fall in the watch area.
An upper low is expected to track over the Big Island late tonight into Thursday, then remain in place into the upcoming weekend. Cold air aloft and instability associated with this upper low combined with a rich supply of tropical moisture will bring the possibility of heavy snow for the Big Island Summits late tonight through Friday night. The threat of heavy accumulating snow exists at elevations above 11,000, putting Hawaii’s Mauna Kea and Mauna Loa areas in the crosshairs for heavy snow.
The Winter Storm Watch is up from later tonight through Friday night. A Winter Storm Watch means there is potential for significant snow or ice accumulations that may impact the summits. Anyone planning travel to the summits, including hikers and campers, should monitor the latest forecasts and consider postponing their trip until improved weather returns. The National Weather Service says heavier bursts of snow could be accompanied by gusty winds, low visibility, and lightning.
Snow is common on the Big Island during winter months. Some snow does fall from time to time outside of winter, though, as strong storms pull down enough upper-level cold air onto the high volcanic summits of the island. It was last April when 6-12″ blanketed Big Island summits too.