Here are the temperature and precipitation rank maps from NOAA and ERA5 respectively:
And to confirm the widespread warmth, Rick's ground-truth temperature anomaly map:
Wind and solar:
According to the ERA5 data, it was an unusually windy winter overall from the west coast to the northern interior, but it wasn't Bering Sea storms that produced this anomaly: MSLP was generally higher than normal from the Chukchi Sea to the Gulf of Alaska (see below). Looking at ASOS wind data from Kaltag as an example, virtually all of the windiest days had winds from the northeast; this is the favored interior wind direction, of course, but it appears the strength of these winds was considerably enhanced by repeated episodes of high pressure to the north and northwest.
Winter temperatures overall were not as low as might be expected during a significant La Niña, and south-central Alaska was actually warmer than normal.
Extremely widespread and very unusual warmth in the northwestern North Pacific may help explain the lack of sustained cold in most of the state despite a negative PDO phase and a circulation pattern (Bering Sea ridge) that was relatively favorable for cold northerly flow. Sea surface temperatures were far above normal to the south of the Aleutians, and that's a source region for Alaskan air during more southerly episodes such as late February and early March.
Extreme precipitation was the biggest story overall, especially for the interior. As Rick Thoman pointed out, snowpack water content on April 1 in Tok was nearly 50% higher than the previous record from way back in 1967 - see below.
Click to enlarge the April 1 snowpack map below. According to NRCS, four subbasins have 250% or more of normal snow water equivalent: Nenana River, Tanana Flats - Tanana River, Healy Lake - Tanana River, and Salcha River. Meltout and breakup continue to be a very pressing concern in terms of flood risk, especially with the forecast continuing to favor below-normal temperatures this month.
I renewed our flood insurance for Fairbanks. There's enough local residual snow to cause problems, and the mid-winter rain effectively sealed road surfaces and adjacent storm drains. Even with -10F this AM daily temps and solar are slowly moving melted water into low spots and on movement areas. The longer it takes to melt the greater the risk for eventual flooding.ReplyDelete
It's hard to envision an uneventful melt season ahead.ReplyDelete
According to Wednesday's NWS breakup outlook, only the North Slope and Copper Basin rivers have "average" breakup flood potential.
About all we can hope for is prolonged cold with clouds and no impactful sudden warming event. Then, periodic brief daily melting followed by cooler nighttime temps. I suppose some wind will help sublimate or evaporate surface moisture. Depending on location there's a 1-2" layer of ice either imbedded in the snowpack and laying on ground surfaces. The effect of this past winter's rains that formed that ice layer will be interesting.ReplyDelete
Another likely effect of the rain induced icing is the potential for reduction in abundance of surface dwelling Microtine Rodents like voles-shrews-lemmings-etc. They depend on under the insulating snow's relative warmth to survive during winter. They build nests-trail paths-food storage caches that likely got flooded in low spots. In the Spring other predators depend on them for food when they emerge from the protective snow cover.Delete
Interesting, Gary. It seems winter rain is "the gift that keeps on giving" - but not in a good way.Delete
La Nina is the guest that won't leave:ReplyDelete
It's good news for fire season.Delete