Sunday, January 03, 2016

Mild start to January.. but colder weather on the way by next weekend

2016 is off to a mild start over southern Manitoba with temperatures above normal along with mainly sunny conditions. (Normal highs right now are -13C with lows of -23C) The mild and tranquil weather pattern is expected to continue much of this week, before a change to significantly colder weather (as in plug-in-your-car cold) moves in later in the week through next weekend.

Winnipeg forecast shows change to much colder weather by next weekend
850 mb temperature plot valid next Monday Jan 11th
from ECMWF shows large Arctic outbreak over Prairies

Temperatures this week will be mainly in the minus single digits with no significant precipitation expected through Thursday. On Friday, a storm system passing through the Dakotas will spread an area of snow across southern Manitoba, with a general 2-5 cm possible. Winds will shift into the north behind this system, heralding the arrival of much colder air for the weekend into early next week. Look for daytime temperatures in the minus 20s and nighttime lows in the minus 30s as the coldest airmass of the season pushes into the Prairies.

So once that cold air gets here, how long will it last?  The coldest core of the airmass looks like it will be coming through Sunday through Tuesday before a slight moderation next week. After that, it's tough to say how January will end up, however given past previous strong El Nino episodes, the odds favour a milder than normal January over southern MB.  Of the past 6 strong El Ninos since 1950, five Januarys were milder than normal here, including during the record strong El Ninos of 1997-98 and 1982-83.  (see composite map below)  Note that cooler than normal weather is more likely over the southern US due to a strong southern jet stream bringing more frequent storm systems and precipitation from California through Texas to the US southeast.  

Composite map showing average temperature anomalies in January
based on average of past 6 strong El Ninos since 1950

1 comment:

  1. Models now showing only a dusting to 2 cm for snowfall amounts for Winnipeg Friday. Bigger story will be the deep freeze coming up beginning Friday night.