Thursday, January 17, 2013

A little snow and a little milder Friday.. then frigid blast for weekend into next week as coldest air so far this season moves in

GEM prog valid 3 pm
Friday afternoon showing
next clipper system to
affect southern MB

A warm front across southern Saskatchewan will be bringing some light snow as well as briefly milder temperatures to the Red River valley overnight into Friday. Snow ahead of the front is spreading into SW Manitoba late today and will continue over SW Manitoba this evening with a few cm possible. Some of this snow will spread into the Red River valley including Winnipeg overnight with a dusting to 2 cm possible into Friday morning as the warm front advances east. Temperatures will be climbing tonight as clouds increase and the warm front approaches. Light snow will continue Friday and by Friday night, a clipper system tracking through the Interlake will bring another area of snow mainly near and north of Winnipeg, while pushing in some milder air from the southwest. Temperatures will be climbing through Friday evening reaching the -5C mark in Winnipeg by midnight Friday. 

GEM prog valid 6 am Saturday
Strong cold front from clipper
will be ushering in cold blast
Saturday with wind chills in -30s
and areas of blowing snow
The mild air will be short lived however as a sharp cold front slices through southern Manitoba overnight Friday into early Saturday.  Strong northerly winds behind the front will usher in much colder air from the Arctic Saturday, with temperatures falling to the minus 20C mark, and bitter windchills near minus 35. Areas of blowing snow are also possible in the Red River valley especially on and outside the Perimeter.

This front will be ushering in the coldest air of the season so far over southern Manitoba for the weekend into early next week, with overnight lows likely dropping into the minus 30s in Winnipeg for the first time in almost two years. Winnipeg's last occurrence of -30C or lower was a -31.6C reading on Feb 25 2011.  Lows of -30C or lower are possible Sunday morning through Tuesday morning with highs in the minus 20s. Moderating temperatures are expected by mid to late week over southern MB.
         

48 comments:

  1. What are the chances of a change in that forecast for Monday as happened with EC tuesday Last Blog Post 10th comment"., 2013
    Anonymous Said 11:55 AM, January 14)...Thursday's forecast..

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  2. NWS Grand Forks mentioning ground blizzard potential in the northern Red River Valley of ND/MN on Saturday. Would probably extend up into southern MB if it happens.

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  3. Derek.. quite possible, especially with any new snow we pick up over the next 36 hours. Best chance for ground blizzard would be over southern RRV with strongest north winds blowing down the valley.

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  4. Hey Rob, do you think the GEM-GLB is overdoing the radiational cooling over the RRV on Monday night? Noticed it's giving an overnight low of ~ -39°C for Winnipeg, which seems...overdone. It will certainly be cold (I'm willing to say we'll have the potential for -34 or -35°C), but I'm not quite sure it'll be that cold. GEMGLB also bottoms out the temperature to similar values Tuesday night as well... :-/

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  5. Brad..

    Yeah, I've noticed a cold bias with GEM-GLB surface temps for Winnipeg area lately. They've been routinely advertising lows in the minus 30s this past week for Winnipeg, and we haven't seen it yet. I agree that a low of -40C for Monday night seems a bit extreme, and that -35C is more likely for YWG. (although that's extreme enough for me!!)

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  6. 2.6 cm of new snow overnight. 23 cm for the month.. 98 cm for the season so far.

    Normal winter snowfall: 110 cm

    Total snow last winter: 80 cm

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  7. When was the last time Winnipeg hit -40?

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  8. Feb 5 2007.. Winnipeg airport recorded a low of -41.7C

    Details.. http://robsobsblog.blogspot.ca/2007/02/winnipeg-hits-40c-mark.html

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  9. Latest guidance tracks clipper a little further south and west, so Winnipeg doesn't get as mild tonight as earlier thought. Going up to -10C mark tonight rather than -5C. Still balmy compared to what's coming up!

    Still on track for another 2-5 cm of snow tonight into early Saturday.

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  10. Looks nasty cold after today again for the next 2 weeks at least, with another round of snow possible later next week. The polar opposite of last winter.

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  11. Blizzard warning now in effect for NE ND/NW MN tomorrow morning and afternoon. Any chance EC may go this route?

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  12. Special weather statement issued for southern Manitoba mentioning colder weather and blowing snow issues for Saturday. If blowing snow is extensive enough, EC may issue "blowing snow" warnings, or if it's bad enough.. blizzard warnings.

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  13. Further to the problems with current Winnipeg weather conditions on Weatheroffice..

    You'll notice that wind and wind chill are not always being displayed. The problem has been traced to the YWG autostation sending out "special" obs that overwrite the official METAR obs sent to Weatheroffice. These special obs have all the pertinent weather data, except for wind, which is needed to calculate wind chill. No wind, no windchill value.

    You will get the wind and windchill data for Winnipeg at the top of the hour, but if the YWG autostation sends an updated obs (which it does frequently if it's snowing or windy) then the wind and windchill data will disappear. This may not happen at all during the hour, or may happen a few minutes after the top of the hour.

    They are aware of the problem, but it won't be addressed until Monday at the earliest. Until then, you can click on "more info">>"past 24 hours" in the current conditions section to get the wind chill value at the top of the hour for Winnipeg. Or you could check other weather sources like The Weather Network or other providers (including my site) to give you updated wind chill values this weekend.

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  14. Rob when will the bulk of snow pass us by tonight. It is hard to tell by the radar as it appears its coming from above radar range. And do you still think it will be in the 2 to 5cm range?

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  15. Daryl.. looks like we're getting into a bit of a break right now, but there's more snow upstream over the Riding Mtns that will be moving in here later this evening. 2-5 cm still looks like a good estimate for us.

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  16. Rob, do you think it's a pretty safe bet to say that we will be below normal through the remainder of this month and into the start of February?

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  17. Yeah it's looking that way. There will likely be some moderating spells now and then but overall it's looking colder than normal for the next little while.

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  18. Picked up another 2.5 cm of snow today through this evening. That puts me up to 25 cm for the month and 100 cm for the season with another 2 or 3 cm possible tonight.

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  19. Blowing snow warnings for areas south of the city.

    BLOWING SNOW WARNING FOR:
    =NEW= STEINBACH - ST. ADOLPHE - DOMINION CITY - VITA - RICHER
    =NEW= PORTAGE LA PRAIRIE - HEADINGLEY - BRUNKILD - CARMAN
    =NEW= MORDEN - WINKLER - ALTONA - EMERSON - MORRIS.

    BLOWING SNOW GIVING POOR VISIBILITIES SATURDAY MORNING AND
    EARLY AFTERNOON.

    ---------------------------------------------------------------------
    ==DISCUSSION==
    A LOW PRESSURE SYSTEM APPROACHING FROM SASKATCHEWAN WILL SPREAD 4 TO
    8 CM OF SNOW THROUGHOUT SOUTHERN MANITOBA TONIGHT. THIS WEATHER
    DISTURBANCE WILL THEN PASS INTO NORTH DAKOTA BY MORNING.
    STRONG NORTHERLY WINDS IN THE WAKE OF THIS SYSTEM WILL STIR UP THIS
    FRESHLY FALLEN SNOW AND GIVE POOR VISIBILITIES IN BLOWING SNOW
    SATURDAY MORNING.

    THERE WILL BE SOME BLOWING SNOW IN OPEN AREAS THROUGHOUT SOUTHERN
    MANITOBA EARLY SATURDAY BUT THE SOUTHERN AND WESTERN PARTS OF THE RED
    RIVER VALLEY WILL SEE THE STRONGEST WINDS. VISIBILITIES IN THESE
    AREAS MAY BE BELOW 1 KILOMETRE FOR A FEW HOURS.

    VISIBILITIES WILL IMPROVE SATURDAY AFTERNOON AS THE WINDS DIMINISH.
    VERY COLD ARCTIC AIR WILL ALSO FLOOD THROUGH SOUTHERN MANITOBA BEHIND
    THIS SYSTEM AND GIVE TEMPERATURES WELL BELOW NORMAL FOR THE NEXT
    SEVERAL DAYS.

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  20. Picked up another 4 cm of snow last night.. for a total of 9 cm since Thursday night. 29 cm for the month, 104 cm for the season. Snow depth is at 37 cm at my place (average)

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  21. Big chill on the way.. After today, we won't get above -20c until Thursday or Friday. Gotta admit, that discussion about stratospheric warming nailed this cold snap.. Long range guidance hinting at normal or even above normal by next weekend but cooling off again after that. Hopefully, not as cold as this outbreak..

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  22. In River Park South... 3.6 cm overnight for a total of 8.4 cm for this system. Month-to-date of 30.7 cm and surprisingly 103.9 cm since October; basically the same as you Rob.

    JJ

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  23. Thanks for the stats JJ.. Remarkably consistent.

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  24. BTW, it looks like they've fixed the issues with the current conditions for Winnipeg on Weatheroffice. Hopefully those issues don't re-surface.. wind and wind chill info will be a high priority over the next few days!

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  25. I took a few more snow measurements from my yard.. average depth is around 40 cm, with variable depths between 35 and 50 cm. Last winter, snow depth didn't really get above 10 cm until the end of February. Maximum depth was 30 cm on March 4-5th, before it was gone completely by the 14th. Totally different story this year.

    The 40 cm snowdepth at my location is the deepest snowdepth since a 45 cm depth on Jan 29 2011, only a couple winters ago. So that really shows how abnormal last winter was. Greatest snow depth I've ever measured was 51 cm on Mar 2nd 2007. Snow records at my location go back to Nov 1998. Greatest snow depth ever recorded at YWG airport since 1955 was 91 cm depth on Jan 30 1956.

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  26. Wow and that 91 cm depth was at the airport, I'm guessing it would have been even deeper inside the city in people's yards. Hard to imagine; hopefully history doesn't repeat itself in that way anytime soon!

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  27. That GEM-GLB sure wants to hurt us on Tues morning, -47C !!!

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  28. Yeah, not sure what's going on with those sfc temps from the GEM-GLB.. it's been overdoing those lows for awhile now. It'll be cold, but not that cold. NAM and Euro both giving YWG -37C Tue am which is cold enough..

    Monday will be a very cold day. 850 cold core of -30C or lower moves over RRV and SE MB, so high temps will struggle in the mid minus 20s along with a 20-25 km/h westerly wind that will produce wind chills in the -40 or lower range. That will set us up for a very cold night Monday night into Tuesday am as wind drops off, with -35C or lower possible for YWG. But not -47C (although -47 windchill certainly possible).

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  29. I wonder if even already the insolation would be too much to support -47°C over the extreme southern Prairies. Those airmasses are going to get modified as they come down from the Arctic, and even up there to get that low they need days on end of radiating in pitch black darkness...

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  30. Would be very interesting to see what the snow depths are for other areas of Manitoba. Riding mountain, interlace, south western, etc. also so far where in southern mb has the coldest temp after the cold snap, and where in southern mb has most snow so far.

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  31. CMC/MSC changed the rounding rules on the current conditions page. On the map YWG shows as -28. On current conditions it's -27. Actual is -27.5C. Kind of strange, since -28 would be the correct way to round it. Why would it change?

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  32. Wind chill warnings for everywhere in southern Manitoba.

    WIND CHILL WARNING FOR:
    =NEW= CITY OF WINNIPEG
    =NEW= STEINBACH - ST. ADOLPHE - DOMINION CITY - VITA - RICHER
    =NEW= SELKIRK - GIMLI - STONEWALL - WOODLANDS - ERIKSDALE
    =NEW= DUGALD - BEAUSEJOUR - GRAND BEACH
    =NEW= PORTAGE LA PRAIRIE - HEADINGLEY - BRUNKILD - CARMAN
    =NEW= MORDEN - WINKLER - ALTONA - EMERSON - MORRIS
    =NEW= BISSETT - NOPIMING PROVINCIAL PARK - PINE FALLS
    =NEW= WHITESHELL - LAC DU BONNET - PINAWA
    =NEW= SPRAGUE - NORTHWEST ANGLE PROVINCIAL FOREST
    =NEW= BRANDON - CARBERRY - TREHERNE
    =NEW= DAUPHIN - ROBLIN - WINNIPEGOSIS
    =NEW= MINNEDOSA - NEEPAWA - RUSSELL - RIDING MOUNTAIN NATIONAL PARK
    =NEW= KILLARNEY - PILOT MOUND - MANITOU
    =NEW= MELITA - BOISSEVAIN - TURTLE MOUNTAIN PROVINCIAL PARK
    =NEW= VIRDEN - SOURIS
    =NEW= STE. ROSE - MCCREARY - ALONSA - GLADSTONE
    =NEW= SWAN RIVER - DUCK MOUNTAIN - PORCUPINE PROVINCIAL FOREST
    =NEW= ARBORG - HECLA - FISHER RIVER - GYPSUMVILLE - ASHERN
    =NEW= BERENS RIVER - LITTLE GRAND RAPIDS - BLOODVEIN - ATIKAKI
    =NEW= POPLAR RIVER
    =NEW= GRAND RAPIDS.

    EXTREME WIND CHILLS OVER THE NEXT 24 HOURS.

    ---------------------------------------------------------------------
    ==DISCUSSION==
    A COLD AIRMASS AND MODERATE NORTHWEST WINDS WILL COMBINE TO PRODUCE
    EXTREME WIND CHILL VALUES OVER SOUTHERN MANITOBA OVER THE NEXT DAY.
    AS OF 10 AM CST, WIND CHILLS ARE ALREADY IN THE MINUS 40 TO MINUS 42
    RANGE OVER WESTERN MANITOBA. WIND CHILLS WILL MODERATE SOMEWHAT
    THROUGHOUT THE DAY BUT THEY WILL BE IN THE MINUS 40 TO MINUS 45 RANGE
    OVERNIGHT AND MONDAY MORNING OVER MOST OF SOUTHERN MANITOBA.

    AT THESE EXTREME WIND CHILL VALUES FROSTBITE ON EXPOSED SKIN MAY
    OCCUR IN LESS THAN 10 MINUTES.

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  33. @Garth: actually, -27 is correct. -27.5 rounds up to -27.

    -DDC

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  34. Actually usually a number like example -27.5 is rounded off to the next number. Anything from .5 and above is rounded off to the next number usually.

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  35. Wow! Winds in Brandon 43 to 79 km/h.

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  36. Wow, thunderstorms in Southern Ontario and Southern Quebec with temperatures up to 8C ahead of the cold front this morning.

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  37. YWG airport already down to -27.6C as of 5 pm... with a low of -29c forecast. Hard to believe that we won't hit -30c tonight given clear skies and NW flow. GEM UMOS guidance insisting we stay above -30c tonight and tomorrow night.. while other guidance is suggesting otherwise.

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  38. Re cold outbreak..

    Although the Arctic Oscillation has been negative for most of the cold season, the PNA index has stayed negative as well.. giving more of a zonal flow, and keeping the arctic air bottled up over the NW Prairies. That stratospheric warming and destabilization of the arctic vortex seems to has caused the flow to buckle, and generate an upper ridge over the west coast of N America - dumping that bitter cold air over us.

    Re overnite lows..

    Tricky temperature forecast for overnite. Other stations are around -25 to -27 C right now. Looks like flow will stay up and be aligned more WNW to westerly with somewhat of a downslope component. Surface high will remain to our west with up to 30 kt flow just off the surface at 925 hPa. Should be enough bursts of mixing to keep us from bottoming out too much overnite. Will probably see temperatures jump around at YWG, as laminar cold drainage flow gets interrupted by periods of mixing.

    Daniel

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  39. Daniel, do you think the streak of not seeing my -30C at YWG Airport will end tonight?

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  40. Quite possible that temps could dip into the low -30s at times overnight (especially YWG), but hopefully we won't bottom out into the mid minus thirties.

    Daniel

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  41. Well, temp is at - 29.1C at YWG Airport as of 7 PM. I'd say the streak should end tonight.

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  42. I see EC has revised it's forecast low for tonight...now -32C....that's sounds more like it. Looks like the other models will be correct with an overnight low in the minus thirties tonight.

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  43. Airport hit -30.0C as of 7:35 pm, down to -30.3C now..

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  44. Well, folks...the streak is over. It sure has been remarkable nonetheless. Going nearly 2 full calendar years without -30C here is truly amazing and almost unheard of.

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  45. Rob, any snow expected for Winnipeg in the next week or so?

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  46. Anonymous..

    Ensembles are hinting at some possible light snow on Thursday, and Euro has it as well. Not much though. Perhaps a little more snow possible early next week as the cold snap moderates.

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  47. Light NW flow has allowed for decoupling over the northern RRV, with temperatures dropping even faster than under the main ridge of high pressure in Saskatchewan. However, gradient remains stronger over SW Manitoba and I still expect temperatures to stabilize or even rise a couple degrees as we tap a westerly flow with gusts up to 30 km/h around 3 am (as per RAP and NAM guidance). We'll see how far temps can sneak down before then. Again, hopefully we stay in the low -30s.

    Daniel

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  48. Must be some crazy mixing out there according to the WeatherFarm map.

    http://imgur.com/dZbmSnX

    I'm heading down to Glenlea to bask in the 21C temperatures! ;)

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