Tag: Lake-Effect Snow

Winter Settles In

Brad Leave a comment

After the blustery entrance of winter that saw the first substantial snowfall of 2015 in the Red River Valley alongside winds gusting anywhere from 70 to 90 km/h, significantly cooler weather will settle over the region for the coming days. There good news is that temperatures won’t be too far from seasonal for this time of year, despite being nearly 15°C colder than they were earlier this week.

Mainly cloudy skies will persist through the Red River Valley today with northwesterly winds of 20–30 km/h with gusts up to around 45–50 km/h. The snow we’ve seen the past couple days is over, but a couple light flurries can’t be ruled out through the day; that said, it wouldn’t be much that will accumulate. The only threat of accumulating snow will come as the winds align and lake-effect snow develops off of Lake Manitoba and Lake Winnipeg. Who will see the snow will depend on exactly what the wind direction is, and at the time it looks like Winnipeg may see a bit of snow from these features. Daytime highs will be slightly below the seasonal normal of –3°C, topping out at –5°C or so.

RDPS 12hr. Precipitation Accumulations
The RDPS precipitation totals for today clearly show the two bands of lake-effect snow off of lake Winnipeg & Lake Manitoba.

The clouds will start breaking up tonight as we head towards a low of –12 to –15°C.

Saturday brings less wind, a little less cloud, but more cold. Mixed skies will preside over a day that sees temperatures climbing to –6°C or so and calm winds. The cooler, calmer weather is thanks to a ridge of high pressure that will be sliding through the area. Despite the cooler weather, the lack of significant winds and a bit of sunshine may end up making Saturday a relatively pleasant day overall. Expect a low near –12°C under partly cloudy skies on Saturday night.

GDPS 12hr. Precipitation Accumulation valid midday Sunday through Sunday evening.
The GDPS is showing a large area of snow pushing through Manitoba on Sunday afternoon and evening.

Sunday’s weather will be largely influenced by the approach of the next low pressure system to impact Winnipeg and the Red River Valley. Starting fairly early in the morning, winds will begin picking up out of the south and will strengthen to around 30–40 km/h by midday.[1] Cloud cover will push in from the northwest while temperatures climb close to the freezing mark. By later in the afternoon, it appears that there will be a fairly good chance that the Red River Valley will see an area of snow push through, possibly dropping another couple cm over the region.

  1. At this point, winds of 30–40 km/h seem reasonable, however if a little more cold air damming occurs in the Red River Valley, which will dependent on the exact track and strength of the ridge of high pressure moving through on Saturday, then stronger winds of 40–50 km/h could possibly develop. We’ll keep an eye on it as the weekend progresses.  ↩

Elsewhere in Weather News: February 28th, 2015

Matthieu Leave a comment

Middle East Sees Snow and Associated Avalanche Danger

This past week the Middle East saw some interesting weather associated with a slow-moving low pressure system that made its way all the way from Turkey to northern India.

[map autofit=”1″ disable_scrollwheel=”1″] [pin tooltip=”Istanbul”]41.005270, 28.97696[/pin] [pin tooltip=”Panjshir”]35.335047, 69.716778[/pin] [/map]

The system first impacted Istanbul, Turkey last week which significantly affected travel across the city as it dropped significant amounts of snow. Most of the precipitation in the region came as rainfall ahead of the low pressure system, but cold air wrapped around on the back side of the system resulted in snow squalls developing off the warm waters of the Black Sea. These snow squalls that formed dropped anywhere from 5 to 20cm, and even locally higher amounts in eastern Istanbul. With the snow that fell earlier in the week, in addition to the fresh snow, one part of the eastern township of Istanbul was able to break its snowfall depth record by recording a snow depth record of 75cm. In other parts of Istanbul depths generally ranged from 20 to 40cm. As many as 200 flights were cancelled as a result of the snow and numerous trees could be seen snapped across the city.

Radar image of strong snow squalls coming off the Black Sea last week.
Radar image of strong snow squalls coming off the Black Sea last week.

Weather in Istanbul is expected to remain above the freezing mark for the weekend, thus the melt that has been ongoing late this past week will continue. Although it’s not unheard of to get snow in the winter in Istanbul, the average snow depth usually remains below 10cm for the winter months. No more snowfall is expected in the next week or so for the city.

The storm slowly continued its trek east dropping more snow and mixed precipitation in Middle East countries such as Israel and Jordan before reaching Afghanistan. Afghanistan and northern India saw major snowfall as a result of this system, especially at higher elevations. As much as 100cm fell in northeast Afghanistan, enhanced by local topography. Several avalanches were also triggered in the region of Panjshir and buried over 100 houses that were located on a mountainside, leading to the deaths of over 200 hundred residents sadly. The northeast part of Afghanistan is a fairly poor region of the country with houses built in dangerous locations that are prone to avalanches and landslides – deadly avalanches are not unheard of and have last occurred in 2012.

Flurries Taper Off, Cool Weather Continues

Brad Leave a comment

A reinforcing shot of Arctic air is pushing into Southern Manitoba for the remainder of the week. The cooler weather will gradually settle things and bring more sunshine than we’ve seen in the past while to the region, but before that happens another day of flurries lies ahead.

Wednesday
-5°C / -9°C
Periods of snow
Thursday
-7°C / -14°C
Mixed skies; chance of light flurries
Friday
-9°C / -15°C
Mainly sunny

Today will bring mainly cloudy skies with flurries continuing to drift southwards from the Interlake as general instability coupled with optimal temperature profiles[1] results in periods of snow throughout the day today. Snow will begin tapering off in the late afternoon or evening as clouds begin to break up and the northerly winds around 30-40km/h shift more northwesterly and gradually weaken.

Temperatures will climb to a high around -5°C and drop to -9 or -10°C tonight.

The forecast sounding for noon today in Winnipeg shows the deep layer of favourable snow-making temperatures – shown in white – that will be in place Wednesday and Thursday.
The forecast sounding for noon today in Winnipeg shows the deep layer of favourable snow-making temperatures – shown in white – that will be in place Wednesday and Thursday.

Thursday will bring mixed skies as clouds gradually clear throughout the day. The same temperature profile will be in place as today, so any low-level clouds will likely be able to produce some light flurry activity, but nothing significant is expected. Winds will shift to westerly at around 15-25km/h for much of the day as a ridge of high pressure slumps into the Dakotas from Saskatchewan. Expect a low near -14 or -15°C under clear skies on Thursday night.

Friday will be a beautifully sunny day, but it comes with the cost of being the coldest day so far. With relatively light west to southwesterly winds flowing out of the high pressure system to our south and southwest, temperatures will climb only to around -9°C. Temperatures will drop back into the mid-minus teens on Friday night under clear skies.

Cold Weather, Flurries for the Weekend

This weekend looks to bring flurries back to Southern Manitoba as another cold front pushes through on Saturday night. Snow will likely be found along the front as well as behind it through the day on Sunday as another unstable northwesterly flow develops.

The GDPS is showing another round of flurries pushing through the Red River Valley on Saturday night into Sunday morning.
The GDPS is showing another round of flurries pushing through the Red River Valley on Saturday night into Sunday morning.

Cold weather is expected to continue behind the front as another shot of Arctic air moves into the province.

  1. Snow grows best in temperatures between around -8°C to -15°C between the surface and around 700mb. The thermal profile over Winnipeg matches those temperatures nearly exactly which will make it very easy for snow to develop.  ↩

Winter’s Blustery Arrival

Brad Leave a comment

A storm system tracking through Manitoba today will bring one last shot of warmer weather alongside some rain before a major pattern shift plunges much of central and eastern North America into a substantial outbreak of Arctic air.

This map of 850mb winds and temperatures shows a potent cold front pushing through Southern Manitoba this afternoon.
This map of 850mb winds and temperatures shows a potent cold front pushing through Southern Manitoba this afternoon.

Friday: Windy and Rainy Afternoon

Friday
8°C / -5°C
Rain ending early this morning; windy with showers this afternoon

Today will start off with overnight rain tapering off fairly early in the morning; the temperature will start off around 2°C and climb to a high of 7 or 8°C under mostly cloudy skies. There’s a slight chance of a few sunny breaks in the morning to midday, but it won’t take too long until the cold front comes sweeping through the Red River Valley.

Winds will strengthen dramatically out of the northwest through the afternoon from nearly calm winds at lunch time to around 40-50km/h with gusts as high as 70km/h. Along with the strong winds, a band of showers will move through with just a few mm expected. Temperatures will drop behind the cold front heading to a low of around -5°C tonight.[1]

Lake-effect snow may rear its head as well tonight as the northwesterlies bring the significantly cooler air over the still-open lakes. Areas in the lee of the lakes may see lake-effect snow develop sometime late in the evening through the overnight period. It looks like Winnipeg will miss out on the lake-effect activity, but we’ll keep an eye on things as they develop this evening.

Significantly Cooler Weekend

Saturday
-2°C / -6°C
Mixed skies, breezy and cool
Sunday
-2°C / -9°C
Mainly sunny

The weekend ahead will be marked by the beginning of a move into a much cooler air mass. Saturday will be a breezy, cool day with northwesterly winds 20-30km/h and a high near -2°C. Winnipeg will sit near the northern edge of a large bank of cloud stretching through Saskatchewan into North Dakota & Minnesota, which should result in mainly cloudy skies. A few sunny breaks are likely, however if things shift a bit further south the day could end up being a whole lot sunnier.

Under any of the cloud stretching through the Red River Valley, some very light flurry activity is possible. No accumulations are expected.

Temperatures will drop to around -6°C under clearing skies on Saturday night.

Sunday will bring mainly sunny skies and lighter winds as a ridge of high pressure sets up over the region. We had mentioned the chance for snow on Sunday in our last post, but as suspected all models are now pushing it well to our south. Expect a daytime high near -2°C and an overnight low near -9°C.

Even Colder Weather Next Week

Unfortunately, even colder weather is expected to move into the region next week, driving temperatures well below the seasonal high of around 0°C.[2]

The 6-10 day temperature outlook from the CPC shows unquestionable certainty of below-normal temperatures for central and eastern North America.
The 6-10 day temperature outlook from the CPC shows unquestionable certainty of below-normal temperatures for central and eastern North America.

A prominent upper-level trough will dig over the eastern United States next week, developing a pipeline of Arctic air straight from the North Pole into the central United States. Expect highs in the mid-minus single digits and lows near -10°C or so. No major systems are forecast to track through, and it appears that most snow that may show up will either be lake-effect or general light flurry activity. The lack of snow cover should help our temperatures from dropping too far, particularly at night.

  1. Plus or minus a degree or two depending exactly on cloud cover.  ↩
  2. Although one could say that in Novemeber, more than most months, “seasonal” or “normal” temperatures are just an average of extremes.  ↩