Here comes the cold!

Skies are clearing this morning across Winnipeg and the Red River Valley this morning as the storm system from last night sweeps eastward into Ontario. But don't let that sunshine today fool you.. it will do nothing to warm things up today. In fact, temperatures will be dropping through the day, with windchills of -45 or lower this afternoon. As of 10 am Brandon is at -30C with a -48 windchill, and that will be heading our way. Tonight, winds will ease off from today's gusty values, but temperatures in the minus 30s will combine with winds of 20-30 km/h to produce dangerous windchills in the -45 to -50 range. Look for these conditions to continue into Wednesday morning before winds drop off in the afternoon and evening. (Note that many school divisions cancel buses for windchills of -45 or lower.. this could be the case across Winnipeg and the Red River valley Wednesday morning.. so be prepared for alternate transportation for the kids tomorrow)

With clear skies and light winds, Wednesday night could see our coldest night of the winter so far with air temperatures dropping into the -35 to -40C range across southern MB, including Winnipeg. But if you think that's cold.. check out some of the temperatures this morning from central and northern Alberta (these are actual temperatures, not windchills).. -44C in Edmonton, -46C in Barrhead, and a reading of -49.5C at a climate station in Manning in far northwest AB. Now that is some serious cold!

WInter Storm Update - Less snow expected

Well, snow amounts with this next storm system are looking rather unimpressive for southern MB as the cold air sweeps in tonight. Models are indicating the bulk of the snow with this storm will track from southwestern SK into central MB (as shown by latest radar) leaving just a few hours of "wrap around" snow for southern MB Monday night. It's possible we may see a couple of cm of snowfall, but I don't expect much more. In fact, some places may just see a dusting of snow as the cold front moves through. The upshot of all this is that blizzard conditions will not be as widespread or as long lasting as they would have been had we received more snow (as earlier expected). As a result, I expect light snow and blowing snow to move into the Red River valley this evening, with near blizzard conditions at times tonight as winds pick up, before things improve by the commute Tuesday morning. Depending on how much new snow falls, there could be blizzard conditions in rural areas for several hours Tuesday morning before things improve by the afternoon or evening. Some road closures are possible outside the city, and rural schools may have bus or class cancellations Tuesday. Conditions in Winnipeg on Tuesday won't be as bad with drifting snow and blowing snow over open areas, but generally good visibilities as the snow will have tapered off by morning. The big story will be the biting cold northwest winds and temperatures in the minus 20s creating windchills of -40 to -45 Tuesday, a big change from the -3 temperatures on Monday.

So in summary, strong winds and much colder temperatures on Tuesday with blowing snow over open areas. Local blizzard conditions Monday night into Tuesday morning, mainly over rural areas. Possible road closures outside the perimeter, with bus or class cancellations possible in rural schools. Minor snowfall storm totals of 2-5 cm. Improving conditions throughout Tuesday. Overall though, things could have been a lot worse with this system (as the GLB model was suggesting a couple of days ago)

Winter Storm Watch Issued for Monday night into Tuesday

Environment Canada has posted a winter storm watch for all of Southern MB for a major winter storm that is expected to affect much of the southern Prairies over the next few days. The worst of the storm is expected to spread into the Brandon-Dauphin areas Monday afternoon reaching Winnipeg and the Red River valley Monday night when blizzard conditions are expected to develop. At this point, it looks like about 5 to perhaps 10 cm of snow is expected across the Red River valley Monday night which will taper off Tuesday morning. Strong northwest winds gusting to 70 km/h will drive much colder air into the area and will create widespread blowing and drifting snow, giving blizzard conditions Monday night into Tuesday morning across much of southern MB. Conditions will be worst in rural areas but blizzard conditions are expected even in Winnipeg for a few hours Monday night into Tuesday morning. As a result, residents should be prepared for the possibility of road and school closures Tuesday as the storm moves across the region. Conditions should improve Tuesday afternoon as the storm moves east into Northwest Ontario.

Note: This storm will be affecting southern SK Sunday night through Monday with widespread blizzard conditions likely. If you have any travel plans to the west tomorrow, be prepared for alternate arrangements as there will likely be numerous road closures and flight cancellations throughout southern SK on Monday. Check the western Canada webcam page to monitor the progress of this storm.

Major winter storm likely Monday into Tuesday..

Things are looking favourable for a major winter storm to affect southern MB early next week with the potential for significant snow and strong winds Monday into Tuesday. A storm system is forecast to develop over Montana Sunday while a surge of Arctic air drives southward from Alberta. This injection of cold air will intensify the storm system Sunday night into Monday as it tracks into North Dakota with snow and blowing snow spreading over much of southern SK into western MB. The storm will intensify even further by Monday night as it tracks over Lake of the Woods, before moving into Northwest Ontario on Tuesday. On this track, snow and blowing snow would be spreading into Winnipeg and the Red River valley late Monday through Monday night into Tuesday morning with strong northerly winds gusting to 70 km/h or more. This could give widespread blizzard conditions over much of southern MB Monday into Tuesday with poor travelling conditions, along with road and school closures. Given how uneventful the weather has been here this month, this storm will certainly bear watching over the next few days as it has the potential to be the worst storm of the winter so far. Stay tuned!

Snowstorm possible by Monday.. followed by another cold blast next week.

Just a heads up that models are hinting at our first significant snowfall of the month over Winnipeg and Southern MB by next Monday with 5-10 cm possible. Snow has been scarce this month over the Winnipeg area with only about 3 cm so far this month. Milder temperatures will be associated with this next system with temperatures possibly reaching -5C by Monday. However, models are indicating a return to below normal temperatures by Tuesday or Wednesday in the wake of this system, as northerly winds usher in another blast of Arctic air from the northwest. Will keep you posted on this developing situation in the days ahead..

In the meantime, enjoy the break from the cold snap over the next few days as the Arctic airmass moves east and moderating temperatures move in from the west. Brisk southerly winds on Thursday will begin bringing in that milder air, but those gusty south winds will make the afternoon high of -15 feel considerably colder. Friday looks much nicer as sunshine and light winds make highs of -15 feel milder. Thus, even though similar temperatures are forecast for Thursday and Friday, Friday will seem much milder due to to the lack of wind.

Windchill is not a temperature

This recent cold spell has once again shown that people are often confusing windchill with an actual temperature.. but these are two entirely different things. Just this morning for example, the headline in the Free Press mentioned how temperatures in Winnipeg, with the wind chill, would approach -45 this morning. In fact, the temperature forecast was -34C which is a lot different than a temperature of -45C, which is different than a windchill of -45.

Temperature is a measure of how much heat energy a parcel of air holds. The more heat energy, the higher the temperature. Windchill on the other hand is an index that estimates the RATE of energy loss of an air parcel given its original heat energy AND a prevailing wind that helps to accelerate the amount of energy leaving the air parcel (i.e. cooling rate). So, temperature is the amount of heat energy an air parcel has.. windchill is the rate of cooling of that air parcel.

Look at it this way... You have a bucket of water at +5C. You put it outside, where the air temperature is a constant +2C, but a wind of 50 km/h is producing a windchill of -5. Will that bucket of water freeze? Of course not. The water will only cool down to the ambient air temperature.. +2C. It can't get any colder than its environment unless its cooled by some other method (e.g. refrigeration) The windchill of -5 merely implies that the water will cool down to +2C at a rate equivalent to that if the water was outside at -5C with no wind. So instead of taking one hour to cool down to +2C, it will only take 10 minutes thanks to that 50 km/h wind. But the water temperature will never go below +2c, no matter how extreme the wind or windchill is. That's the effect of windchill. It describes an equivalent RATE OF COOLING, not an actual temperature. So if it's -20C with a -40 windchill, your car will likely still start if it's not plugged in because the battery will never get below -20C. On the other hand, if it's -40C with no windchill, your car will not start if it's not plugged in because the battery will cool off to -40C (given it's outside long enough).

Before 2001, the Prairies used a windchill index that was given in watts/sq metre (e.g 1800 W/m2) This was a more scientifically valid measure of what windchill actually was.. a rate of cooling, expressed in the amount of energy loss in watts per square metre of area. However in 2001, the windchill was re-calculated and standardized for all of North America to the windchill index we use today, which was mainly based on the more common "equivalent temperature" index being used in Southern Ontario and the United States. A survey conducted at that time showed that most people found the watts/sq metre unit "too technical" a term to fully understand.

Windchill update

I've updated my website main page to include a graphic on windchill readings from my station (dial image showing latest windchill, plus hi/low stats) Click the dial image to get more windchill info. Windchill will be the main story Friday.

IMPORTANT: Wind readings from my station are much lower than exposed sites such as the airport, or rooftop locations. My anemometer is only about 15 feet off the ground, and is surrounded by trees and buildings. As a result, windchill readings from my site frequently underestimate the actual windchill for the area. This is why my site should never be used to make official decisions with respect to windchill! The station at PJ school has better exposure for winds (on the rooftop) for Charleswood area windchill values.

Frigid Friday!

A weak weather system will cross southern Manitoba on Thursday bringing increasing clouds and some flurries to the area. Only a dusting of snow is expected with this system along with slightly moderating temperatures, but the main story will be the cold air that will follow in the wake of this system Thursday night into Friday. Temperatures will drop into the minus 30 range by Friday morning, and brisk northwest winds of 30 km/h will give extreme windchill values below minus 40. Extreme windchill values will persist through Friday as brisk northwest winds continue along with daytime highs only in the minus 20s. The cold weather will continue through the weekend although winds should be a little lighter. Get that block heater ready!

Strong winds Tuesday and Wednesday

Enjoy the light winds today.. because things are going to a lot different within the next 24 hours. By tonight, southerly winds are going to be increasing over southern MB in advance of a developing storm system over Alberta. By Tuesday morning, southerly winds will be howling through the Red River valley with gusts to 70 km/h or more giving local blowing and drifting snow in open areas. Temperatures will moderate through the day with highs near -5 by evening, but much of the day will feel colder due to the strong winds, especially in the morning. Little new snow is expected on Tuesday however by Tuesday night, a cold front will push through southern MB bringing some snow with winds shifting into the northwest giving gusts again in the 70 km/h range or locally higher. This will create areas of blowing and drifting snow overnight Tuesday into Wednesday, with near-blizzard conditions possible in rural areas depending on how much fresh snow falls Tuesday night. The northwest winds will also mark the change to a more prolonged period of cold weather moving into southern MB with below normal temperatures likely through next week at least.

www.robsobs.ca now online!

Well, it's official now.. Rob's Obs now has it's own registered domain name - www.robsobs.ca! So if you ever need to access my site and you don't have access to bookmarks, or don't want to search through Google.. robsobs.ca will now take you directly to my site. Kind of cool! (Thanks to Scott of www.steinbachweather.ca for the advice on setting this up)

By the way, I was looking into robsobs.com as well, but it was already taken! Seems like there's a guy named Rob in Maryland who posts his views and commentary on American politics and sports. No weather talk though!

The week ahead..

After a week with little weather to talk about, the weather this week will be a little more interesting (which isn't a good thing for some people!) Today is starting off clear and cold as an Arctic airmass over northern MB spills southward. This cold airmass will begin moving eastward on Monday as a storm system begins developing over Western Canada. Strong southerly winds ahead of the system will move into the Red River valley Monday night into Tuesday with gusts to 70 km/h likely. This will produce considerable drifting snow especially across east-west highways, with local blowing snow giving reduced visibilities in open areas. The southerly winds will advect milder air into southern MB on Tuesday with highs of -5 expected by late afternoon. However, don't let that high of -5 fool you.. the strong southerly winds will make it feel much colder, especially in the morning. This system will bring an area of snow into Winnipeg by Tuesday night as a cold front advances east signalling the arrival of much colder air spreading in over western Canada this week. Gusty northwest winds will bring this colder airmass into southern MB Tuesday night into Wednesday with temperatures dropping to below normal values. Current forecasts indicate normal temperatures for Wednesday and Thursday but don't be surprised to see these temperature forecasts trend downwards over the next few days.

Pattern change coming up next week

Temperatures in southern MB have been running above normal since mid December, but it looks like the pattern will be changing towards below normal temperatures by the middle of next week. (image shows CPC's 6-10 day temperature outlook)

Long range models are coming in line indicating a strong storm system will cross the Prairies on Monday and Tuesday next week, with strong northwest winds and colder temperatures moving in behind it. Current concensus takes the storm track through the interlake area of MB with the bulk of the snow generally north of the Yellowhead. However all of southern MB will see some snow out of this, with gusty winds and falling temperatures in the wake of the system along with areas of blowing and drifting snow. Once the cold air comes in, models indicate it will be around for awhile (at least a week or two) but it's too early to say with any degree of confidence at this point. Well, the weather's been too boring around here lately.. at least this will be some weather to talk about!

January thaw!

A nice January thaw in progress over southern MB with afternoon temperatures above the freezing mark in Winnipeg.. our first above freezing temperature since Nov 19th. Normal highs right now are around -13C so we are running way above normal. The mild temperatures and occasional sunshine will help to melt that bit of freezing rain from last night that gave some slippery conditions this morning.