El Niño taking hold? Milder air blows in next week

There are signs El Niño may be getting a firmer grip in the tropical Pacific. Tropical Pacific Sea Surface Temperature (SST) anomalies have been fluctuating the past few weeks. Now, a ribbon of consistently warmer than average surface water is pooling near the equator. And it may already be driving weather impacts from southern California to Minnesota.

Tropical Pacific SST anomalies via NOAA.

We know that El Niño winters skew milder than average overall in about 70 to 80-percent of years in Minnesota. That doesn’t mean an absence of snow and cold. It just means when you average it all out, temperatures run a few degrees milder than average overall.

NOAA

Split-flow

El Niño winters favor a “split-flow” jet stream configuration that can bottle up bitter Arctic air in the Polar regions more often than not. The active southern branch of the sub-tropical jet stream can drive enhanced storminess, rain, and snow from southern California through the Gulf Coast states.

NOAA

L.A. rain and mudslides

El Niño exhibit A?

A powerful storm swirling in off the Pacific has dumped more than 4-inches of rain in southern California.

That storm has the rainy season off to a strong start in southern California.

Thursday’s rain triggered rockslides and debris flows in recent burn areas.

Mountain snow

At higher elevations, it’s snow. Talk about instant gridlock.

Upper air shift next week

The jet stream pattern across North America is beginning to look a lot like El Niño next week. A zonal (west-east) flow pattern will blow milder air in from the North Pacific next week.

NOAA upper air forecast for 6 pm CST Tuesday, December 11.

The precise magnitude of the warmup next week is still in flux. But a string of days in the low 30s seems likely at this point.

NOAA forecast temperatures for Minneapolis via Weather Bell.

Snow hole

Minnesota’s early season storm track has favored northern and southern Minnesota. Storms have largely steered clear fo central Minnesota so far this season. That’s evident on Thursday’s snow cover analysis from the Minnesota DNR.

Chocolate ice cream sandwich?

Minnesota DNR.

With a potential thaw next week we may eat away at the fringes of this snow cover map next week.

Stay tuned.