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CPC 6-10 day outlook looks cool
for southern MB/Ontario.
Pleasant summerlike weather is in store for southern Manitoba over the next few days as a ridge of high pressure over Manitoba gradually pushes east into NW Ontario. Temperatures will climb to about 24C today and into the upper 20s Thursday, before a weak cool front pushes through Thursday night bringing a threat of showers and thunderstorms across the RRV into early Friday. Pleasant weather is expected Friday and Saturday with generally sunny skies and temperatures in the mid 20s. Unfortunately, a cold front pushing in from the north will bring a threat of showers Sunday along with a northerly push of cooler air that will likely result in high temperatures of only 18-20C for Monday and Tuesday... well below the normal high of 26C for this time of year. This northerly flow will be the result of a massive upper ridge building over western Canada early next week that will bring an extended heat wave over BC, with temperatures in the 35-40C range in the Okanagan and Fraser Valleys. A gradual moderating trend is expected over southern Manitoba by the middle to end of next week.. but as of yet, there are no indications of a pattern change to hot dry weather over us in the near future.
Current model forecast highs for Monday for Winnipeg:ReplyDelete
Cool northerly flow with partly cloudy skies, possible showers. So that sunny 28C forecast for Monday is looking way too optimistic based on current guidance. Weather Network calling for a high of 18C Monday which seems more realistic.
So given the concensus that Monday and Tuesday will be a good 5-10C below normal, why does EC's forecast call for above normal highs of 28C those days?
A little background..
EC's forecasts for Days 3-7 in the Prairies are completely computer-generated automated forecasts with no forecaster intervention. Day 3-5 forecasts use the GDPS model which is a medium range model with fairly good resolution, while Day 6-7 use a bias-adjusted Canadian ensemble model (CEPS) which has a coarser resolution and is based on averages of several model runs. This ensemble model however has been noted to have a warm and dry bias over the Prairies, so it tends to be too optimistic in its forecasts (in terms of overforecasting sun and warm temperatures) It also has a bit of a lag in adjusting to changing patterns, so it will often be too slow in picking up on a rapid change to cool or warm spells. Note that by Day 6 and 7, forecast temperature errors average around 6-7C, so a forecast high of 28C on Day 6 has an equal chance of being anywhere between 21 to 35C. Quite the range.
As expected, high for Monday has dropped from 28C to 20C, and Sunday is now down to 18C (after a forecast high of 30C two days ago) Day 6-7 warm bias still evident with high of 27C noted for Tuesday and 29C Wednesday. Shave 5C off those for more realistic forecasts. Good news is that we should be seeing a nice warming trend after the 15th, with temps back to normal and even above by end of next week.Delete
Correction on the average forecast temperature error for day 6-7. It's more like 4C in the summer, thus for a forecast high of 28C, the actual high would generally be between 24C and 32C on average. Usually, it will be on the lower end due to the warm bias.Delete
Rob, what do Winnipeg's severe weather weather chances look like for tomorrow night?ReplyDelete
I'd say chances are slim for Winnipeg. I think the strongest storms will be west of us in the evening going into the Interlake at night where forcing will be better. We may see some weakening thunderstorms here after midnight, but I don't expect anything severe for us at this point. The setup was much better for us Saturday night for some good storms here, but they went south and weakened before they reached Winnipeg. Of course, there's always a chance of getting surprised with a stronger cell coming through here even with a subtle setup, but given our track record lately, I wouldn't count on it.Delete
WEll have some hope rob well get there soon anything can happen. Tmrw I won't waste my day waiting for storms. Thx for the friendly post.Delete
Rob, given the outlook into next week, is it too simplistic to think we are really in the same pattern we experienced all winter ? i.e. we can't seem to build any stretch of warm weather and it's unsettled with POP darn near every day. It seems hope is fast fading for any stretch of sunny hot weather this summer.Is it unusual to be in such an extended pattern and what does it take for a pattern change to occur ?ReplyDelete
Our pattern now is not as bad as it was in the winter.. At least we're getting many more days near normal, a few above, and our below normal outbreaks haven't been exceptionally cold or prolonged. So although we haven't flipped to a 2012 type pattern when we were consistently above normal, we have modified somewhat from the persistent cold pattern we had this past winter. I'm hopeful that we will continue to moderate and get into a warmer pattern from August through the fall and into the winter.Delete
Looks like cold front will be moving through us by late afternoon Saturday.. a little earlier than I indicated in my blog post. We should get into the low to mid 20s by mid afternoon, but then a band of showers and scattered thunderstorms will be pushing in from the north along the cold front. Big drop in temperatures behind the front Saturday evening with temperatures falling into the teens, along with gusty northwest winds. Unseasonably cool Sunday with highs only in the teens (16-18C) along with clouds and scattered showers. Cold pool moving over Lake Winnipeg may even spawn waterspouts over the lake. Very fall like. Still cool Monday but improving by mid week with a warming trend mid to late week.ReplyDelete
You where talking about how automated/ unautomated EC's forecast is day by day. how about other public forecast and how automated/ unautomated they are– such as TWN or Accuweather?
Love this blog :•),
Most other agencies also have automated forecasts, especially for the long term. But they may use different model guidance or algorithms than EC uses.. which may or may not be better. I don't know their verification stats. I'm not against automated forecasts.. I just wish they would use more sophisticated algorithms and ensemble guidance to make better forecasts. For example, it's been shown that using an ensemble of various model guidance can give better longer range forecasts than just using one model.Delete
Nice squall line came though here around 330 pm with some good gusts and brief downpours with only 3 mm at my place. All in all, just a gusty squall line. Noticeably cooler behind the front. Tomorrow looks very cool. Depending how quickly we cloud over, we could be looking at highs of only 15-17C Sunday. Record low maximum (i.e. coolest daytime high) for July 13th is 16.7C in 1884 and 1950. We could beat that mark, which is never a good record to break in the summer. In addition, with a 3C cold core at 850 mb moving over 19C lake waters, we could also be seeing isolated waterspouts off Lake Winnipeg by Sunday afternoon and evening.ReplyDelete
By the way, you've probably noticed a lack of updates on this blog during active weather, especially during the summer. I've come to really prefer using Twitter to post updates on active weather.. I find it quicker, timelier and more proactive than using a blog format. Plus I can post images on the fly quickly and really interact with more people than I can reach here. You can follow me on Twitter at @robsobs I will continue to post periodic entries on general weather events here on my blog.. but for real time weather updates, I'll mainly be using Twitter.Delete
Fall like day on tap today with early sunshine giving way to clouds, and some light rain moving in this morning into the evening. Unseasonably cool today with highs about 10C below normal.. only around 16-17C. We'll be challenging the record low max of 16.7C for today (set in 1884 and 1950) Normally, we should be around 26C at this time of year. In addition NW winds will be quite brisk today , especially over the lakes today and tonight due to the cool air over the relatively warmer waters.. so NW winds of 40G60 km/h over/lee lakes with gusts to 70 possible this afternoon into tonight. Not good news for southern and eastern shorelines given the very high water levels.ReplyDelete
We then get into a nice warming trend through the work week with highs near normal by Wednesday and even above by late week. Unsettled conditions possible by the weekend with a threat of showers and tstorms, but staying warm. (current forecast of "sunny" for Friday and Saturday is a tad optimistic.. not surprising given these are Day 6/7 forecasts)
There's a hint that we'll be getting into above normal temperatures next week, but I'll reserve that judgement until there's more consensus and consistency. Sure hope it pans out though.. would love to get a nice prolonged taste of summer.
Well, if it's going to be miserable, we might as well set a record for it. And we have.. coldest daytime maximum on record for July 13th in Winnipeg with a high of only 15.7C today.. 10C below normal and besting the previous record by a full degree. JJ from Winnipeg weather blog also points out that today was the lowest July maximum here since a 14.6C reading on July 2 1997... 17 years ago! (Note however that an even more intense storm system on July 12 2008 brought severe NW winds and heavy rain over southern MB, and even gales over the MB lakes. Winnipeg had a high of 16.6C that day (not a record low max), but that was recorded in the morning before temperatures fell to 13-14C by midday and stayed there all day with strong NW winds and a driving rain. So believe it or not, it CAN be worse than today was!)Delete
By the way, Sunday's high of 15.7C is normal for late September. Mother Nature owes us 27C degree weather in late September to make up for her obvious oversight..Delete
Some BC station recorded 40C+ temperatures yesterday.ReplyDelete
Ashcroft, BC at 41.3C was the warmest spot. This is actually the warmest it has been in Canada since 2007.
Surprised they don't have heat warnings out there (although they do have a special weather statement about the hot weather that says pretty much the same thing as a heat warning..)Delete
Looking at daily temperature and precip records for the summer months, we see that since 1990, Winnipeg has set only 6 new record highs between June 1st and August 31st. Meanwhile during the same period, we've set 9 new daily record lows, 11 record low maximums, and 14 record high minimum temperatures. In addition, since 1990, we've also set 22 new daily rainfall records between June 1st and August 31st. It's an interesting way to look at how our summers have trended over the past 25 years or so. With the lack of record highs, and an increased number of record high minimum temperatures and rainfall records, it points to summers that have become wetter, more humid, and cloudier. That makes it more difficult to get those extreme hot days that were more frequent or easier to attain when our summers were drier. That's not to say we don't get sunny hot days in the summer.. we do. It's just that they're not as frequent, long lasting or extreme as they used to be in a drier climate.ReplyDelete
What I don't get is the higher number of record low temperatures which you wouldn't expect in cloudier wetter summers. That could be a result of cooler nights following cloudy rain cooled days (like yesterday) Admittedly, this is a simplistic look at our overall summer climate based on these extremes, and doesn't necessarily reflect what our future summers may bring (which could also see hot dry years) But it's an interesting analysis of what kind of summers we've been experiencing over the past 25 years or so.