Sunday, May 15, 2016
After a chilly weekend.. things looking up this week.
It was a chilly weekend over southern Manitoba with high temperatures only near 11C Saturday, and 15C today along with some showers. But the rest of the week is looking up as the cool airmass moves east and a warmer upper pattern re-establishes itself over the Prairies. The result will be a warmer and drier week coming up with ample sunshine and highs back to the 20C mark by Tuesday, and mid to upper 20s by the end of the week. The early outlook for the Victoria Day long weekend looks warm and increasingly humid with a chance of showers and thunderstorms by Monday.
Posted by rob at 4:51 PM
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Odd that the forecast high for Friday is only 20C for Winnipeg. That forecast is based on the GDPS model which shows at least 25C for Winnipeg and southern MB that day. Poor temperature post processing likely to blame.ReplyDelete
It continues to like things could get interesting over the long weekend as models continue to hint at warm and increasingly moist airbags which could lead to the first thunderstorm event this season in Southern Manitoba at some point over the weekend. Still too early for specifics regarding severe weather potential. Nonetheless finally something to talk about that has more to do with summer rather than winter for a change.ReplyDelete
Correction...moist airmass not airbags. Darn autocorrect.Delete
I thought airbag could be legit lolDelete
Drought pattern hanging tough with only 10-15 mm of precipitation in the last 5-6 weeks. Massive rex/omega block feature over central N. America promoting day after day of very low dewpoints, brisk winds and warm temperatures. This is giving elevated risk for soil erosion and wildfires. Some higher moisture finally starts working in by this weekend as mentioned - at least bringing up relative humidity levels somewhat.ReplyDelete
Uncertainty w.r.t. precipitation potential for late in the weekend. Western trough finally moves east and sends a surface front through Sunday/Monday. However some indication of a split in QPF (from models like GFS) as front stalls to our SE with LLJ producing heavy rain somewhere over SE Manitoba/NW Ontario/Upper Midwest. Upper low hangs back over Northern Prairies putting our region in a dry slot. Upper SW flow re-establishes itself later in the week as southern branch of jetstream energy undercuts the massive ridge. Disturbance may tap plains LLJ giving another chance of much needed rain.
Some indications of western ridge and NW flow aloft gaining control again after this.. an atypical pattern for June (which is normally our wettest month), and somewhat reminiscent of previous drought years such as 2006 and 2011.
I don't see any indication of the ridging out West happening again, it mainly shows a southwestern flow for the last week of May and a ridging and southwestern flow setup over the plains and Central Canada. Both the CFS and the GEFS, GEPS latch onto this idea. No sign of any Northwest Flow, that seems odd in the middle of June to be honest. That is more of a winter time pattern and Spring setup, go check it out for yourself at http://www.tropicaltidbits.com/analysis/models/. Kind regards, Michael.Delete
12Z GFS clearly shows NW flow beginning on Sun 29 May. This transitions to a broad upper ridge which eventually retrogrades and gives us a pronounced NW flow by Sat 04 Jun.ReplyDelete
Rob, what's the latest on the thunderstorm potential here in Winnipeg and the RRV for Sunday and Monday? Any severe potential?ReplyDelete
Latest guidance points to the potential for some thunderstorms to fire up over southwest MB late Sunday into Sunday evening, but then weakening by the time it gets to Winnipeg/RRV Sunday night. More thunderstorms could fire up again Monday afternoon/evening but those will be mainly east of Winnipeg into southeast MB. Overall, it looks like Winnipeg could escape the whole weekend with minimal rain... but well gave to see how things develop later Sunday to get a better idea.ReplyDelete
Rob, there are lots of rumblings that we are headed for a very hot and dry summer. What are your thoughts on this?ReplyDelete
I don't take a lot of stock in any seasonal outlook.. except winter outlooks which do show *some* skill in cases of strong ENSO events (like this past winter) Any other season (including summer) do not show much predictive skill with overall global climate patterns and past analogues. Summers can be influenced so much by convective precipitation, and that's something global climate models just can't resolve. So I really don't take any of those summer predictions too seriously. It's more of a wait and see approach.Delete
That being said, the planet as a whole is currently on a record warm streak for the past 12 months, and in particular 2016 is off to a historically warm start beyond anything the planet has experienced since at least 1880. This would seem to tip the balance towards getting a hot summer here.. but whether we get it or other parts of Canada or North America do remains to be seen.
Models are leaning towards development of a line or complex of showers and thunderstorms with heavy rain over central ND this evening spreading northward into the Red River valley and SE MB tonight. A couple models even showing potential for local amounts of 25-50 mm of rain in narrow bands of heavier showers/thunderstorms over parts of the RRV. Other hi-res models are suggesting this complex will track over SE MB and graze the RRV tonight. We'll see what happens.. but keep an eye on central ND this afternoon into this evening to see if and where this convection fires up. Hopefully it's in a favourable spot that will benefit much of the RRV tonight into early Monday with some rain.ReplyDelete
Yeah, multiple parameters lining up to suggest heavy rainfall for some locations. Storms firing now in N Dakota are training along region of moisture convergence and forcing along the back edge of LLJ and along surface front. With unidirectional SSW flow and LLJ only slowly moving east, significant rain is possible by tomorrow morning. Question remains exactly where the heaviest line of convection will set up.. these storms appear like they will only brush Winnipeg, but high resolution models suggest a more general area of lighter rain and t-showers later tonite into early tomorrow morning for Winnipeg.Delete
Well, we got a good soaking after all.. Nice area of tstorms over ND last evening quickly surged north last night into the RRV giving some decent lightning and welcome rain. I picked up 31.6 mm in my official backyard rain gauge here in Charleswood while my Davis station recorded 34 mm (there will always be a slight difference between the two.. but I always use my official gauge as an official amount.) Looks like generally 20-30 mm across the city with 35-37 mm in the Southdale/Sage Creek areas. Winnipeg airport got 21 mm and The Forks had 22 mm.Delete
Winnipeg actually got some of the higher amounts in the RRV, with general amounts of 15-25 mm in the RRV last night.
Yeah, and parts of SE Manitoba looked to have received not very much.Delete
Surprised that with the main convective line setting up from west of Winnipeg to northern RRV, the airport only ended up with 21 mm. Seems like undercatch - most spots saw 30-40 mm under that band.
A great storm to kick off the 2016 storm season! Rob how come thunderstorm observations are not in the past 24 conditions on EC? They reported them at midnight but the conditions on the past 24 hours just say light rain showersReplyDelete
Those "past 24 hour conditions" on EC's website are based solely on the observations at the top of the hour from Winnipeg airport. Last night at midnight, the airport observer was calling 15 miles in a light rainshower, which is what is noted on EC's website as the current condition for midnight. 5 minutes later at 12:05 am, the observer updated the obs to 15 miles in a light thunderstorm.. but this observation doesn't appear on the past table of the past 24 hours.. only observations at the top of the hour do. The airport observer continued to show thunderstorms until 1 am, when the observer went back to calling it just a rainshower. So just going by the hourly obs, it looks like the thunderstorm was missed.. when in fact, it occurred between hourly observations.Delete
To see all the actual observations from the airport (even the off hour observations), you can check Weather Underground almanac site at..
Rob, is there a severe thunderstorm potential for us Wednesday-Thursday?ReplyDelete
I think we have a good chance of seeing more tstorms Wednesday into Wed night over southern MB inlcuding the RRV, but severe potential looks low at this point. Not much shear to work with so storms will be mainly heavy rain producers.Delete
Most models not very bullish even on rainfall totals with generally 5-10 mm projected. However, given the general pattern - with the upper low over Saskatchewan moving east and southerly fetch of moisture - precipitation totals could be higher if there is good linkage between the disturbance and the plains LLJ.. which would tap considerable elevated instability. NAM favours this scenario and gives us over 20 mm.Delete
Rob can we officially call off our drought watch. We seem to 100mms over normal ytd rain and it is still coming down. That seems to be the story for most of Southern Sask and Alberta as well . Or am i hallucinating?ReplyDelete
Upper low sitting over us starts to wash out by tomorrow. Models spit out some more QPF, but given what we are seeing today.. not much is likely.ReplyDelete
A series of new disturbances move up in SW flow aloft Friday and Saturday, however most models take them to our east. Flow transitions to a more zonal pattern - with eventually a trough setting up to our west. This will bring a return to a more active period with more precipitation possible in the Tuesday to Thursday timeframe.
Thereafter, trough closes and evolves into a Hudson Bay vortex. This will be accompanied by an anomalous western ridge and NW flow pattern which is still projected by GFS.
Yeah it looks like June will start off below normal unfortunately. Too early to say how long it will last but hopefully it's not too prolonged but there are hints that the cooler weather could be with us through mid June. It sure was nice to have a warm May for a change. Unfortunately June won't follow suit, at least the 1st half of the month anyways.ReplyDelete
Rob, Signs seem to be pointing towards cooler than normal temps for at least the 1st half of June. What are your thoughts on this?ReplyDelete
Looks unsettled for the rest of May with almost daily rain chances through June 1st.. then below normal temps likely to start off June. Not sure how long it will stay that way, but long range guidance is hinting at upper ridging over the west coast for the first part of June which usually means greater odds of below normal temps for us (or at least a lack of sustained heat.) But again, not sure how long that will that last or how strong that west coast ridging will be.Delete
Muddled weather pattern for this weekend. No clear signals for organized precipitation except for disturbance moving up from central plains - which should pass to our east. However with lingering higher dewpoints, and uncertainty as to extent of drying and high pressure ridge building in - scattered showers here and there can't be ruled out. Clearly precipitation signal for mid-week.Delete
It was chilly here as well (in Montreal), but now it is hot and humid.ReplyDelete