Tag: Freezing Rain

Elsewhere in Weather News: February 1st, 2014

Matthieu Leave a comment

Southeast US Paralyzed by Storm

On Tuesday a large trough was in place over the eastern half of the US. The longwave trough extended all the way down to the southeastern states and brought adverse weather conditions along with it. This trough did not produce the typical severe weather the southeast would see around this time of the year; thunderstorms and flooding rain, but produced an event featuring snow, ice pellets and freezing rain.

Arctic air flooded in behind the cold front all the way down from Texas to the Gulf of Mexico to Florida, providing good environment for freezing precipitation right behind the front. Freezing rain fell as far south as Pensacola in the Florida panhandle where over 200km of interstate had to be shut down because it was deemed to be too dangerous for travel. The last time Pensacola saw snow was 2010 – it melted the same day it fell. In comparison, Atlanta saw a trace of snow in 2008. This time around the city received 6cm, which snarled traffic on the commute back home. Officials decided to not cancel schools and students were stranded in schools and buses overnight until the next morning. Commuters were in the same situation, being stranded on roads overnight as many commuters are not accustomed to winter weather leading to many accidents. The sub-freezing temperatures across the Deep South also wreaked havoc, bursting water pipes above ground.

Wednesday morning surface temperatures. Freezing temperatures can be seen reaching all the way down into Mexico and the Deep South. (Source: Twisterdata)
Wednesday morning surface temperatures. Freezing temperatures can be seen reaching all the way down into Mexico and the Deep South. (Source: Twisterdata)

Medium range models continue to show cold air entrenched across the Canadian Prairies and most of the United States, even infiltrating into the Deep South again next week. A persistent ridge off the West Coast, partially associated with the well above normal temperatures in the North Pacific, can be blamed for the persistent troughing and Arctic air over Canada and US the past few weeks. Longer range models do show the ridge eventually breaking down in a week but this remains to be seen as it’s still a long ways out.

Mid-January Storm To Bring All Manner of Nasty Weather

Brad Leave a comment

A powerful storm system is pushing into Southern Manitoba this morning and will become the first major storm of the year. This storm will impact the entirety of Manitoba and bring very strong winds, heavy snow, near-blizzard conditions and a good chance of some freezing rain. Read on to find out where will see what as we break this thing down.

  • Significant weather expected: strong winds (and blowing snow), freezing rain and heavy snowfall.

  • Expected storm-total snowfall amounts from this system.

Disclaimer: I could write many more words than I have time to write about this system. As such, I’m going to just explicitly state right now that while I may mention areas outside the Red River Valley, the focus of this post will be for the weather expected in Winnipeg & the Red River Valley.

We’ll start out with the good news: temperatures are expected to stay near or above normal[1] through the remainder of the week; no horribly cold Arctic air is expected to slam southwards into the Prairies with this system. That’s about where the good news ends, though.

As we progress through this morning, an area of snow will move into the Red River Valley, pushing in from the west ahead of the incoming warm front. The low pressure centre is currently in northeastern Saskatchewan and will begin to dive southeast into Central Manitoba later this morning. Winds will strengthen out of the south this morning up to around 40-50km/h with gusts as high as 70km/h. Despite the relatively mild temperatures – we’re sitting at around -10°C – extensive blowing snow will likely be an issue in areas to the south of Winnipeg[2] thanks to the strength of the winds.

Wednesday

3°C / -11°C
Snow beginning this morning. Very windy. Risk of freezing rain this afternoon. Flurries overnight with blizzard conditions in the Red River Valley.

The heaviest snowfall will pass to the north and east of the city where a heavy snowfall warning is in effect for 10-15cm of snow. Here in the Red River Valley we’ll see a fair gradient in snowfall amounts from the southwest corner to the northeast corner thanks to how the precipitation spreads in from northwest to southeast. Through the day today, areas in the southwest corner can expect the lighter end of the snowfall with only around 2-5cm accumulation by the evening. Here in Winnipeg we’ll see from 5-10cm of snow while closer to 10cm of snow will fall to our north and east.

Our winds, as mentioned before, will become quite strong out of the south. They’ll lighten a little bit for the early afternoon as they swing to the west as the low pressure system moves through the Interlake and the warm front pushes east of the Red River Valley. Our temperature will jump up to around +2 or +3°C and we’ll see a break in any blowing snow that’s happening. By mid-to-late afternoon, though, a cold front will be approaching. Winds will shift a little more to the northwest and we’ll see a risk for some freezing rain just ahead of and along the cold front as it pushes through. In addition, there is the potential for some fairly heavy bursts of snow along the cold front with some models hinting that there may be a fair amount of convective activity associated with it[3]. Winds will shift straight out of the northwest by the evening and strengthen considerably to 50km/h with gusts potentially as high as 80km/h overnight here in Winnipeg.

This wind will readily whip up the freshly fallen snow in the RRV and produce near-zero or white-out conditions on area highways. Despite the fact that temperatures will not drop too quickly – only to around -10°C overnight – it will still be a brutal night. Continued flurry activity will likely continue through the night, compounding the visibility problems presented by the winds alone.

Thursday


⇒ -10°C / -20°C
Windy with blowing snow. Mainly cloudy.

The snow will taper off early on Thursday, but poor visibilities will continue through much of the day as the strong northwest winds persist at 40-50km/h at least into the early afternoon. Temperatures will remain fairly steady at around -10°C.

By evening the wind will taper off as a ridge of high pressure moves into the province, bringing an end to any blowing snow left in the Red River Valley. The clouds will also scatter out and we’ll drop to a chilly -21°C for our overnight low.

Friday & The Weekend


-10°C / -14°C
Cloudy periods with a chance of afternoon flurries.

Friday will start off sunny but some cloudy periods will develop as a warm front pushes into the Red River Valley. We’ll become overcast in the mid-to-late afternoon and see a chance for a few flurries as the warm front pushes eastwards. This front will usher in warmer air for the weekend with highs near the 0°C mark and overnight lows dropping just shy of around -10°C.

  1. Normal daytime highs are around -13°C for mid-January.  ↩
  2. As usual, with a southerly wind the highways that will be affected most are those that run west/east.  ↩
  3. As evidenced by lightning in Northern Alberta last night.  ↩

A Cooler End to the Weekend

Brad Leave a comment

We’ll see two more days of temperatures near or just above 0°C before a cold front sweeps through Southern Manitoba bringing minimal precipitation and cooler weather.

12hr. QPF valid Sunday morning

Precipitation amounts for Saturday night from the NAM forecast model.

Today and Tomorrow

We’ll be off to a cloudy morning with fog patches through the entire Red River Valley; the fog may be quite dense in some areas, so if you’re travelling be prepared to potentially face near-zero visibilities at times. The fog will lift through the morning and by mid-afternoon the sun should be poking out once and a while. We’ll be on our way to a high of around +1°C with light winds. We’ll see increasing cloudiness tonight as the aforementioned system pushes towards Southern Manitoba. The cloud cover will help us keep our overnight low a bit higher than it has been lately with the temperature only expected to dip down to about -5°C. It’s likely that well see the redevelopment of fog patches again tonight.

Friday

Fog patches lifting this morning with gradual clearing.
1°C / -5°C
Saturday

Fog patches lifting then a mix of sun and cloud.
3°C
Saturday Night

A few flurries with the risk of freezing rain.
-12°C

We’ll see temperatures slowly climb back up above 0°C today as the cold front approaches the Red River Valley. Any fog patches that form overnight will lift fairly quickly in the morning as we head into another nice day with a mix of sun and cloud as the temperature climbs to +2 or +3°C.

A cold front will sweep across the Red River Valley tonight, bringing some flurries with it. There’s some uncertainty to the distribution of the snow: the models tend to spread it out, but all simultaneously hint towards a narrow band of heavier precipitation setting up. It’s hard to tell what’s going to happen this early, but suffice to say that there will almost certainly be a few flurries with the potential for local accumulations of 2-4cm somewhere in the RRV. In addition to the snow, there will be the potential for some patchy freezing rain as there will likely be some precipitation before all our warmer air aloft is scoured out by the cold front. Accumulations of freezing rain should not be significant, but may be enough to slick up roadways a little.

Sunday

Saturday

Chance of flurries. Clearing.
-6°C / -15°C

There will be a few lingering flurries about on Sunday morning, but they should clear out by midday and skies will then clear out. Sitting on the back-side of the cold front, our temperature will only climb to around -6°C, although it might be a little colder than that if clouds linger further into the day.

It looks like the cold weather will only stick around for a couple days until temperatures rebound back to the 0°C mark.

Freezing Rain to Mark Return of Colder Weather

Brad Leave a comment

Our wild weather will continue as another low pressure system tracking through the northern Prairies will bring with it mild temperatures and the probable risk for freezing rain over the Red River Valley, including Winnipeg.

Sounding for Winnipeg @ 5:00PM Local Time

Sounding for Winnipeg at 5:00PM local time. Note the significant AFL shaded in red.

Warm air will be pumped over the Red River Valley today as strong southerly winds develop ahead of a major low pressure system set to bring heavy snowfall to the northern reaches of Manitoba. 850mb temperatures will climb to nearly +5°C today, providing an ample AFL[1]. The bulk of the precipitation with this system will be constrained to central and northern Manitoba, where anywhere from 5–20cm of snow are expected. Regions that were hit hard Monday will mostly be spared as the heaviest snow will fall further north than Monday’s system.

We’ll have breezy southerly winds in the Red River Valley today at around 40km/h with gusts to 60km/h with temperatures climbing all the way up towards –1°C by the late afternoon/early evening. As the warm front approaches the RRV in the late afternoon, it looks that an area of showers will blossom along it. There’s still some uncertainty in exactly where the precipitation will be and how quickly it will develop, but it looks probable that areas in the Red River Valley north of Morris will see freezing rain late this afternoon. Areas south of Morris have a very real chance as well, however there’s a little more uncertainty in how far south the band of showers will stretch.

We aren’t expecting huge amounts of freezing rain this afternoon; the quick-moving nature of this system will mean that even if the rain is intense, it’s likely that we’ll only 1–2mm of it. Keep in mind, though, that while 1–2mm isn’t a very significant amount for regular rainfall, it is a significant amount of freezing rain. It’s likely that the freezing rain will fall during the rush-hour period in Winnipeg and quickly turn roads into slick little skating rinks fairly quickly. If you drive to work, especially into or through the downtown core of Winnipeg, expect a slow commute this evening.

Skies will clear overnight as a weak cold front pushes across the RRV and Thursday will bring mainly sunny skies with temperatures falling through the day to –8°C by evening.. Winds will be breezy from the NW at about 30km/h before letting up in the afternoon. Another arctic ridge will push into Southern Manitoba, bringing another shot of cold weather with it. Temperatures will dip all the way to around –20°C on Thursday night and only recover to around –15°C on Friday.

Temperatures will level out a bit for the weekend with highs near –10°C for Saturday & Sunday, but it looks that a weak storm track will move over us, bringing cloudy skies and plenty of chances for light snow. We’ll have more on this weekend’s weather on Friday morning.

Northern Manitoba Communities Buried Under Massive Snowfall

An incredibly powerful low pressure system tracking through Northern Manitoba on Monday brought a nearly unprecedented snowfall event to many communities. Hardest hit were Norway House and Gods Lake Narrows[2] where over 2 feet of snow fell. Environment Canada sent out a brief summary yesterday on the event:

A major winter storm moved across Central Manitoba on Monday, bringing with it some very heavy snowfalls. The heaviest band fell from the Norway House area east to the Ontario border, with numerous public reports of knee- to waist-deep snow accompanied by drifting as high as two metres. Lesser but still significant amounts were received by the surrounding regions of Gillam, Grand Rapids, and The Pas.

Unofficial snowfall totals are as follows:

Location Snowfall
Norway House 60–90 cm
Gods Lake Narrows 60–90 cm
Island Lake 60 cm
Oxford House 45 cm
Cross Lake 30–40 cm
Gillam 35 cm
Grand rapids 30 cm
The Pas 30 cm
Mafeking 23 cm

While official snowfall records for northern Manitoba are hard to come by, it seems likely that these snowfalls are record-high snowfalls for a 24–36 hour period for Norway House, Gods Lake Narrows, and Island Lake. From what I could find, 1-day record-high snowfall totals in Northern Manitoba generally sit around the 40–50cm mark; these totals of 2–3 feet easily quash those records, and whether or not they end up as official “heaviest snowfall” records may come down to exactly how much fell in any given 24-hour period.

Norway House Snowfall Satellite Image

A visible composite satellite image from during Norway House/Island Lake snow storm.

The snowfall came from an extremely potent, moisture-laden low pressure system that managed to find the right combination of convective snowfall and duration. As shown in the satellite image above, a very strong moisture feed was evident as it surged northwards into the low pressure system rooted near The Pas. This system slowly tracked eastwards, producing heavy snow in the above localities for upwards of 18–24 hours.

A system like this is definitely an extremely uncommon one and is difficult to forecast due to the sparseness of surface observations and lack of RADAR imagery. It will likely be just now as this is published that some roads finally begin to be cleared and people are able to return to a more normal daily routine.

A further 5–10cm of snow is expected for the Norway House and Island Lake regions with the system passing through Manitoba today.

  1. Above Freezing Level  ↩
  2. Gods Lake Narrows is a small community north of Island Lake, MB.  ↩