90-100% chance of >12 inches of snow now depicted by models for MB/ND


Morning analysis depicts snow currently impacting portions of southern Manitoba, while rain mostly dominates along the hwy 75 corridor and east. This is only the first round in a long-duration snowfall event. Ensemble means are now throwing some impressive snowfall accumulation totals >24 inches (60cm+) through Friday evening (see below).

Here is the latest discussion by the Prairie and Arctic Storm Prediction Centre:


PRAIRIES...SOUTHWESTERLY FLOW ALOFT OVER SOUTHERN MB CONTINUES TO GUIDE VARIOUS SHORTWAVES ALONG BAROCLINIC ZONE THROUGH SOUTHERN MB. RELATIVELY LIGHT MIXED PRECIPITATION WEDNESDAY NIGHT WILL INTENSIFY TODAY WITH NEXT IMPULSE NOW WARMING UP IN NORTH DAKOTA. SNOWFALL ACCUMULATIONS REMAIN DIFFICULT TO FCST MAINLY IN REGARDS TO PERCENTAGE OF SNOW MELTING ON CONTACT. GENERALLY HEAVIEST PRECIPITATION (IN THE ORDER OF 10 TO 15 CM) EXPECTED ALONG MB ESCARPMENT. WITH THE APPROACH OF THE WYOMING UPPER LOW AND ASSOCIATED COLORADO LOW FRIDAY, MUCH HIGHER SNOWFALL AMOUNTS EXPECTED. POTENTIAL FOR 30 TO 50 CM IN SOUTHERN RRV FOCUSED AGAIN ALONG ESCARPMENT. AGAIN, AMOUNT OF MELTING ON GROUND CONTACT THE WILD CARD. RED RIVER THE APPROXIMATE DIVIDING LINE BETWEEN SNOW TO THE WEST AND RAIN TO THE EAST. THIS RAIN/SNOW BOUNDARY WILL WAVER OVER THE NEXT 72 HOURS. THE WINNIPEG FORECAST PARTICULARLY DIFFICULT BECAUSE OF THIS. MORE RAIN WILL FALL IN SOUTHEASTERN MB WHERE NEAR FLOODING CONDITIONS PRE-EXIST. THERE IS A RISK OF STRONGER PRECIPITATION BANDS FRIDAY GIVING A QUICK SHOT OF HEAVY SNOW TO WINNIPEG. IN ADDITION STRONG GRADIENT WINDS FRIDAY WITH GUSTS UP TO 100 KM/H OFF THE MB LAKES. NON CLASSICAL FREEZING RAIN POSSIBLE ALONG RAIN SNOW BOUNDERY BUT SURFACE TEMPERATURES SHOULD REMAIN JUST ABOVE FREEZING MARK. WINTER STORM WARNING ISSUED FOR AREAS MOST LIKELY TO GET HEAVY SNOW AND/OR STRONG WINDS.

Figure 3 (above) shows that there is a 90-100% chance of seeing 12 inches (30cm) or more of snow within the next 24hrs. This is substantial and will only be the first round of snow we see.


Warnings

4:25 AM CDT Thursday 10 October 2019 Winter storm warning in effect for areas in red


An approaching Colorado low will continue to bring a mix of wet snow or rain to southern Manitoba today. Snowfall amounts of 10 to 15 cm are expected today mainly along the Manitoba escarpment. The snowfall may ease a little Thursday night.

This Colorado low will bring very heavy snow to parts of southern Manitoba Friday as it passes through the area. In addition, very strong northerly winds are forecast for Friday. The extreme winds and heavy snowfall will persist into Saturday.

The combination of wind and wet snow may pose a problem with tree branches or power lines. Consider postponing non-essential travel until conditions improve. Prepare for quickly changing and deteriorating travel conditions. Visibility may be suddenly reduced at times in heavy snow.