Friday, March 03, 2017

Milder weekend ahead.. winter storm system looms for Monday

After a cold start to March, things will be turning milder this weekend as a southerly flow flushes out the Arctic airmass currently over the eastern Prairies. In Winnipeg, temperatures are expected to climb to the freezing mark on Saturday and +2C on Sunday. Note however that Saturday will see gusty south winds gusting 60-70 km/h, so that high of 0C will feel a lot colder. Sunday looks a lot more pleasant with lighter winds and temperatures above freezing.

12Z NAM model valid Monday afternoon shows
rain over SE MB and snow west
Attention then turns to a potential winter storm system that will be impacting southern Manitoba Monday into Tuesday. At this time, models are indicating the development of a storm system over the western United States Sunday that will track across the Dakotas Monday and intensify as it moves into NW Ontario by Monday night. This system will likely start off with some rain or freezing rain over the RRV and SE Manitoba with snow over western MB and he Interlake regions. As the storm pushes towards the Ontario border later Monday, strong northwest winds on the backside of the system will draw in colder air and spread snow and blowing snow across the remainder of southern Manitoba Monday afternoon into Monday night. Travel conditions could become hazardous across southern MB through the day Monday into Monday night, especially with falling temperatures and increasing winds that will freeze up any standing water from leftover rain or melted snow.

12Z GDPS model valid Monday evening shows
intensifying storm over Lake of the Woods 
There's still a lot of uncertainty on the track of this system and the timing when precipitation will change over to snow which will impact overall snow totals.  A track across southeast MB would push the heaviest snow over western Manitoba through the Interlake regions (possibly 15-25 cm) with lesser amounts (5-10 cm) over the RRV and SE MB.  A track through Lake of the Woods or east would bring heavier snow over the southern Interlake and RRV. We'll continue to monitor trends over the next few days to get a better idea of how this storm will track, and what impacts it will have for southern MB. In the meantime, be prepared for a potential return of wintery conditions Monday into Tuesday. Stay tuned..

Monday, February 20, 2017

Thaw coming to an end.. colder weather on the way

After another mid winter mild spell that featured thawing temperatures and rain, things will be cooling off this week as a colder airmass spreads over western Canada. Preceding the cooldown will be a fast moving clipper system that may bring a coating of snow (Tr - 3 cm) Tuesday night into early Wednesday across Winnipeg/srn MB.  Temperatures will be dropping behind the system for Thursday into the weekend, with temperatures more seasonable for late February (normal high -7, low -17C)  That will be good news for outdoor enthusiasts and winter events such as the Festival du Voyageur which has had to cancel several outdoor events due to the mild springlike weather. In addition, no major storm systems are expected through early next week over southern MB, so the colder weather should also be accompanied by dry and mainly sunny conditions. Good opportunity to finally wash that car again!  

Monday, February 06, 2017

Rob's Obs website URL changing..


Please note that as of March 6 2017, Shaw will be retiring their members.shaw.ca web server services, which hosts my Rob's Obs website.  As a result, the URL for my Rob's Obs website (http://members.shaw.ca/mainweb/robsobs/robs/home.htm) and all related webpages will no longer be valid after that date. Over the next couple of weeks, I will be moving my website and webpages over to a server hosted by A Weather Moment.   

The new URL for my main Rob's Obs website will be
http://aweathermoment.com/robs-obs/robsobs/robs/home.htm    

I hope to have most of my webpages moved over to the Weather Moment server by March 6th. Note also that my www.robsobs.ca URL will be mirrored over to the the above URL as of that date as well.  Please update your bookmarks to the above URL if you would like to continue to access my site. Thank you.

(Of course, you can always google Rob's Obs anytime to find it the site as well)    

Monday, January 23, 2017

January thaw melts records in Winnipeg

It was a record breaking mild weekend in Winnipeg as an unprecedented stretch of above freezing temperatures turned ice rinks and streets into puddles and slush across the city. The temperature at Winnipeg airport (where official temperatures are measured) rose above freezing at 4 am Friday morning Jan 20th, and stayed above freezing until 11 pm Sunday evening Jan 22nd. The stretch of 67 straight hours above freezing set a new record for the longest January thaw on record in Winnipeg, eclipsing the old mark of 44 straight hours Jan 8-9th 2002.     


Hourly temperature records for Winnipeg airport go back to 1953, but even looking at daily records shows that the 67 hour thaw is likely the longest such stretch in January in Winnipeg since records began in 1873. The only other comparable January thaw* would have been Jan 9 - 12 1928 when the temperature failed to drop below -1.6C over the 4 day period. However even then, there wasn't a 48 hour period where the temperature was consistently above 0C, so it appears this most recent warm spell is the longest such streak for January in Winnipeg in 144 years of weather records.  (*NOTE: "January thaw" in this case is defined by consecutive hourly temperatures of 0.0C or more. There have been longer stretches in January where daily high temperatures have reached 0.0C or higher, but temperatures dropped below freezing at night. The longest stretch with daily highs of 0.0C or more in Winnipeg in January was 9 straight days in January 1942 from the 16-24th, with 14 in total during the month, including Winnipeg's all time January high of +7.8C on the 23rd)  

The 3 day thaw also set new daily record high minimum temperatures in Winnipeg from Jan 20 to 22nd inclusive:

Record daily minimum temperatures set Jan 20-22 2017
(table courtesy of @jjcwpg)
Normal lows for this time of year are near -23C, so these temperatures are almost 25C above normal lows! The low of +0.9C on Jan 21st was only the third time in 144 years where the temperature did not drop below freezing during a January day in Winnipeg. The only other dates were Jan 12 1928 (minimum of +1.1C), and Jan 14 1894 (minimum of 0.0C).  Thus, a 67 hour streak of above freezing temperatures in January in Winnipeg is an exceedingly rare occurrence. Note also that 2.9 mm of rain fell on Jan 20th, the 2nd highest rainfall for any January day or month since 1873 (second only to the 3.8 mm that fell on Jan 20 1944) The mild weather, although welcome after a frigid first half of January, forced the closure of city rinks and skating trails as ice melted into slush and giant puddles. The thaw also resulted in locally slippery streets and walkways as water slicked up packed snow and ice.   

Temperatures are slowly cooling off this week to below freezing, but will remain above normal values the rest of the week before more seasonable temperatures return by the weekend.   

Saturday, January 14, 2017

A nice warmup beginning this weekend after frigid week..

Mother Nature is finally relenting.. but not after giving southern Manitoba a  parting shot of Arctic like weather this past week including blinding blizzard conditions Thursday, then bone-chilling frigid cold Friday with windchills of -40 to -45.  The good news is that the worst of the bitter cold is over.. for at least a week anyways.. as a milder Pacific flow sets up over the Prairies this week, pushing out Arctic air that has been entrenched over southern Manitoba much of the month.  Today will see temperatures near the normal high of -13C, and with sunshine and light winds, it will feel some 20 degrees warmer than Friday. Sunday is looking even better as temperatures finally climb into the minus single digits for the first time since Jan 1st. The rest of the week is looking wonderful.. dry and mild with temperatures well above normal reaching the freezing mark by mid week, then a January thaw likely by the end of the week as temperatures climb to +1 to +3C over the Red River valley. This will be welcome news for winter weary Manitobans who have had endure 2 straight weeks of cold and snow, icy roads and general cabin fever.  The good news is that the warmup will not be accompanied by any major weather systems this week, so the week is not only looking mild, but precipitation free as well!  The next system that poses a threat for precipitation over the RRV will be next weekend (Jan 21st-22nd) with some possible snow, rain or freezing rain moving into southern MB. Until then .. time to finally get back outside and enjoy the outdoors. Let the warmup begin!