This week will start off on the cool side as a brisk northerly flow builds in behind this weekend’s Colorado Low. Temperatures on Monday will be downright chilly for mid-May.
Cool weather will dominate southern Manitoba on Monday
Monday
We’ll see skies gradually clear today as the system that brought us rain (and snow) this weekend departs. It will remain very chilly though, as temperatures barely climb into positive values. Daytime highs will only make it into the low to mid single digits, which should hopefully be enough to melt a good amount of the snow that fell. Winds will be northerly at 40 km/h gusting to 60 km/h, but will taper off throughout the day as the system pushes further off to the east.
Tuesday
Tuesday will remain on the cool side, but should be a fairly pleasant day (at least relative to the weekend!). High pressure will build into the region behind the weekend’s low pressure system, bringing much calmer conditions. High temperatures will climb into the teens under mainly sunny skies and light winds.
Wednesday
Wednesday will be quite nice as temperatures climb into the upper teens under mainly sunny skies. Winds will be relatively light and from the north-west, making for another pleasant day.
Long Range
The long range forecast shows conditions remaining slightly below normal through the end of the work-week. There are hints that we’ll see warmer conditions build in by the weekend, but it’s too early to say for sure. In general, models show us transitioning to a generally warmer pattern toward the end of the month, although there will still be some cooler days mixed in here and there.
Winnipeg, and many other regions in the Red River Valley, received the most significant rainfall so far this year yesterday as an area of moderate rain moved into the province from North Dakota and stalled out for much of the day. Rainfall totals in most places were near 20–30mm with slightly higher amounts in the southwestern Red River Valley:
Rainfall totals for the May 14, 2015
Location
Rainfall Total (mm)
Letellier
41
Altona
37.6
Morris
34.2
Winkler
29.8
Steinbach
27.8
Winnipeg
24
Dugald
22
Elm Creek
12.6
Portage la Prairie
9.6
The Altona/Letellier areas seem to be the winners for total rainfall with almost 1.5” of rain in total. Unfortunately for farmers who are still working at getting seed into the ground, there won’t be much of a reprieve from wet weather before more rain is on the way as another major low pressure system is hot on the heels of the previous one and is set to bring a whole host of unsettled, pleasant and stormy weather for the May long weekend.
Pleasant Friday, then Downhill
Friday
18°C / 7°C
Partly Cloudy
Today will be a very pleasant day across the Red River Valley with mainly sunny skies and temperatures climbing into the high teens under partly cloudy skies. Winds will be fairly light out of the northwest. Friday night will see temperatures drop to around 7°C under clear skies. The nice weather won’t last too long, though, as a potent low pressure system moving into the Northern Plains of the United States tonight will result in cloud and some light rain spreading across Southern Manitoba early on Saturday. The heaviest rainfall will hold off until much later in the day, however, as this system will end up being strongly driven by convection.
SPC Day 3 Convective Outlook valid Saturday May 16, 2015
The SPC[1] in the US currently has a slight risk of severe thunderstorms in their outlook for Saturday scrunched right up the Canadian border. Further north in our area, it looks like an initial shot of some showers associated with elevated convection will lift through the region early in the day. Temperatures will warm towards the 20°C mark with an increasing risk of showers or thunderstorms.
Saturday
20°C / 9°C
Cloudy; scattered showers with the risk of a thunderstorm
Later in the afternoon, best indications at this point are that an area of thunderstorms will initiate in North Dakota and push northeastwards through the Red River Valley. It looks like precipitation will most likely be showers or weak thunderstorms, however the outside chance exists that an isolated severe thunderstorm may be seen. A thunderstorm outlook later will be issued later today covering all of Southern Manitoba.
A few showers will be likely through the overnight hours as the temperature drops to 9°C or so.
Sunday will be the most significant precipitation day with rainfall intensifying through the morning into the afternoon. There’s some uncertainty as to where the western cut-off will be for the rain, but general consensus at this point is that the entirety of the Red River Valley will see rain on Sunday.[2] Total accumulations are hard to nail down at this point, but look to be in the 25–50mm range.
Sunday
10°C / -3°C
Rain
Things take an unwelcome turn on Sunday evening as colder air works its way into Southern Manitoba on the back-side of the system. Rain may become mixed with or switch over to snow as it begins tapering off. No significant snow accumulations are expected. Temperatures will drop off to around –3°C on Sunday night with winds gradually tapering off.
Holiday Monday A Cool Improvement
Looking ahead to the start of next week, it looks like Monday will mark the transition out of this active pattern we’ve been in. Sunny skies and exceptionally cool weather look to be on tap with highs struggling to get to even 10°C[3]. Conditions will improve over the subsequent days with drier weather and temperatures returning to the seasonal mark.
The GDPS is a bit of an outlier, keeping rain wrapped tightly to the surface low pressure system in Minnesota and keeping the bulk of Sunday’s rain southeast of Winnipeg. ↩
The summer-like temperatures seen in Winnipeg over the past couple days will continue into the weekend with daytime highs 10°C above normal. A cold front will finally push through on Saturday evening, bringing an end to the exceptional warmth and ushering in a return to seasonal temperatures.
Today will be a gorgeous day in the Red River Valley with light winds and daytime highs near 25°C with a bit of a southwesterly wind. Expect a few clouds tonight with a low near 10°C.
Tomorrow will be a more interesting day as a more organized southerly flow develops over the Red River Valley ahead of an approaching low pressure system. Temperatures will climb to around 27°C while a meager amount of moisture pools through the Red River Valley ahead of an approaching trough. As the trough moves into the Red River Valley, it’s looking quite possible that we may see a few thunderstorms develop, however the chance is largely conditional.
This forecast sounding valid Saturday afternoon for Winnipeg from the NAM model shows a deep layer of instability, adequate moisture and favorable shear for thunderstorm development.
Given the fairly low amount of moisture available, cloud bases would likely be very high; the forecast sounding indicates cloud bases near 10,000ft which would mean the biggest threat from the storms would be strong wind gusts. Some hail might be a threat further south in North Dakota, perhaps sneaking onto extreme southeastern Manitoba, but overall it looks more like we’ll see a few weak thunderstorms develop capable of producing some fairly gusty winds. The overall environment, save for the lack of moisture, looks quite favorable for the development of the storms, though. Winds will generally be out of the south to southwest at around 30 gusting 50km/h with a slight chance for some 50 gusting 70km/h winds in the afternoon.
Some cloud will linger overnight as temperatures dip to around 9°C with winds relatively light out of the west to northwest.
Sunday will bring a bit of cloudiness and slightly cooler temperatures with a daytime high of “only” 19°C. Winds could be gusty out of the northwest for a few hours beginning in the morning before settling down to 30 gusting 50km/h for the afternoon. Sunday night looks mainly clear with a low near 5°C.
Some of the warmest weather so far this year will move into the region today, drawn eastwards by a fairly strong spring storm moving through the Central Prairies. The warmth is not meant to last, though, as a strong cold front pushes through and brings below-normal temperatures for the remainder of the week.
Wednesday
16°C / 2°C
Windy with sunny breaks this afternoon
Thursday
⇓ -2°C / -12°C
Cloudy & windy; chance of showers or flurries
Friday
0°C / -8°C
Mainly sunny & cool
Today will be quite a warm day thanks to very mild air over our region; 925mb temperatures are expected to climb to around 9°C, which should translate to daytime highs near 15 or 16°C once we sunshine this afternoon. Speaking of sunshine, while today is starting off cloudy, we should the cloud cover break up this afternoon as the dry slot associated with the Central Prairie low moves across Southern Manitoba. Alongside the sunshine and clearing will be fairly gusty westerly winds to 30–40km/h with gusts as high as 60km/h. The winds will taper off in the evening as we head to an overnight low of around +2°C.
The RPDS shows an area of light precipitation moving through the Red River Valley on Thursday with a relatively tight pressure gradient that will produce gusty northerly winds.
Thursday will be a significantly less pleasant day as a cold front pushes through Southern Manitoba, bringing with it cooler temperatures, gusty northerly winds and a fairly good chance for some shower or flurry activity. Temperatures in Winnipeg will slide through the morning, settling near –1 or –2°C for much of the afternoon as gusty northerly winds to around 40km/h tap cooler air from the north. The best chance for any shower or flurry activity would be through the morning & early afternoon. Skies will clear out Thursday evening as we head to a low near –12°C.
Friday will be a benign weather day for Winnipeg & the Red River Valley, but temperatures will be well below normal. Daytime highs will only be around +1 or +2°C through the Red River Valley, which is a few degrees below normal for this time of year. Fortunately, winds will be light and with that increasingly strong April sun shining, it won’t feel so bad. Expect temperatures to drop to around –8°C on Friday night with partly cloudy skies.
Quiet Weekend Ahead
The weekend is looking fairly quiet for Winnipeg with seasonal to slightly below-seasonal temperatures and a few clouds. A ridge of high pressure building in from the Arctic looks to keep most disturbances to the south of Winnipeg, however with the main frontal zone setting up near the U.S. border and a few shortwaves rippling along, areas along the U.S. border in Southern Manitoba may see a few showers or flurries through the weekend. Nothing significant is expected.
The NAEFS 8-14 day temperature anomaly forecast show above-seasonal warmth returning to Manitoba.
In the longer range, it looks fairly likely that we’ll see a return to above normal temperatures through the second week of April as the storm track shifts back further north; while above normal temperatures will return, it looks like much of the warm weather will be associated with weather disturbances, making it likely that we’ll see more of a “roller coaster” temperature pattern than a prolonged period of warm, dry weather. Only time will tell, though! For now, expect a few cool days and then a stretch of near-seasonal temperatures.
