August will be ending on a warm and muggy note, with morning clouds giving way to some afternoon sun along with humid conditions. A storm system developing over Montana will trigger a few thunderstorms over eastern SK and western MB later today into this evening, some possibly severe with damaging winds and large hail, along with a risk of isolated tornadoes. The system will sweep a cold front across southern MB tonight with showers and thunderstorms possible across the Red River valley through the Interlake regions. Cooler weather is on tap for the first few days of September behind this system.
Yes Rob from looking at things at our office looking pretty good for severe MCS tonight somewhere over nrn ND into southern Manitoba. The low level jet fed of moist air seems to be anchored very near or just south of Intl border 06z-12z. Good synoptic type rains with this system over much of southern/cntrl Manitoba into ern Sask. Fargo is now below Flood stage...it has had been above flood stage for 150 days this year so far.ReplyDelete
Despite some favorable parameters.. I have a few doubts about tonite's possible event. Main wave and nose of LLJ (deceleration of air causes convergence and extra lift) set up off to our NW. We will need cells to propogate down into that strong LLJ. Problem is they will have to overcome increasingly warm 700 hPa temps reaching 10 C .. so southward extent may be an issue. On the other hand, models like GFS hint at a weak wave moving across N Dakota overnite.. yet another split in precip? GFS is also further norht with the parent wave. Window of best opportunity is fairly brief - between 4 to 6 am as LLJ moves off quickly to the east.ReplyDelete
Personally, I think something will sprout up in around the low pressure center in W ND in the late evening then move north-easterly into southern MB.ReplyDelete
I'm not saying you're wrong Daniel, it's just my personal opinion.
Daniel is saying it likely won't happen, Anon is saying it will. So yes Anon, you are saying Daniel is wrong. We're all adults here, I think Daniel can take it. :)ReplyDelete
Mean flow would advect convection into S Manitoba. Question is how much would it weaken as it gets away from the best forcing and the warm mid-level temps. The strongest cells often tend to propogate down into the LLJ and in this case would stay in N Dakota. That is the picture the 12Z GFS is painting, and it is what has commmonly happened this season.. I hope its wrong.ReplyDelete
re anom & anom IIReplyDelete
We are all entitled to our opinions. To clarify.. I am pointing that there is uncertainty (ie some doubt) based on what I see in some of the models. I'd say we have a 50/50 chance depending on the exact track of the two lows and how much warm air comes in at 700 hPa etc..
If all goes well tonight we will have a chance for storms and I mean MCS thunderstorms. In order for it to work out we need the ACC cloudcover to clear out to allow for some dewpoints to rise, thereafter we need the LLJ wind strength to speed up to 40kt as forecast, the available 2500 J/KG has to be there or were done for.ReplyDelete
Heres what I think some storms will form in SE Sask as predicted and follow a easterly track as the low itself moves east. Hitting us by early morning. Some additional cells could form around us overnight or even propogate into a line as mentioned by EC earlier. All in all we could have a chance of seeing something later on tonight. I agree With daniels prediction I'd still say 50/50. Best of luck for storms.
what do you think?
I'll have a look at the radar, and other bulletins. I will keep you updated.
Multicellular Thunderstorms are forming straight N to S from Moose Jaw,Saskatchwan all the way south to Medora,ND. they look like they are moving NE at 60km/h and in the next hour or so they could form into numerous storms (Squall line). these storms range from being subsevere to supercell storms, in various locations.ReplyDelete
Our chances are increasing by the second.
The Wpg Shield Generator has had days to recharge and will be turned on at 4AM tomorrow morning :)ReplyDelete
Anon: I don't think the sheild will be on at 4am, we had a storm hit the airport yesterday at around 6pm with 8mm of rain in 20 min it couldve knocked the thing out. At least thats my opinion.ReplyDelete
Storm prospects overnight into early tomorrow morning area looking good as of right now.ReplyDelete
Frequent cloud to ground lighting is occuring with the storms in North Dakota. A good light show is on tap tonight!!ReplyDelete
Williston, North Dakota recorded a 61 mph wind gust about 10 minutes ago. That line in NW ND means business. It's moving quickly, too!ReplyDelete
Look at that squall line form in north dakota. I hope I don't sleep through the big light show tonight!!!ReplyDelete
Given the current area of convection out over Saskatchewan, Montana etc.. I still expect a general split in precipitation organizing around a band of mid level frontogenesis from Saskatchewan into Central Manitoba, and along the nose of the main LLJ somewhere between Winnipeg and Grand Forks.ReplyDelete
Uncertainty regarding the strength and location of best LLJ convergence makes it difficult to say how Winnipeg will be affected by the southern system (NAM further north with LLJ up to S Manitoba, and the high resolution RUC & HRRR further south). Models like RUC are much weaker with LLJ and show little if any precip developing at all over the intl border area while HRRR is very aggressive with a robust jet of 60 kts and paints a huge region of convection engulfing almost all of S Manitoba.
I think areas in the southern RRV and down towards Grand Forks are favored for the most intense convection assuming the cap is overcome (storms are currently forming as far south as the 14 C isotherm at 750 hPa in SW N Dakota) where cells can propagate down into the best low level inflow of moist air.
Still looks 50/50 to me for Winnipeg to get intense convection :P with best chance also still around the 4 - 6 AM timeframe.
The next little while will be telling.. I would watch for a possible split in that line over western N Dakota and Saskatchewan as it encounter a blob of dry air from 850 up thru 700 hPa. The position of that dry region in relation to the LLJ will be key in dictating where convection sets up.ReplyDelete
Elevated storm set-ups are always interesting to follow. So far so good with a solid line from SW MB all the way down to S ND.ReplyDelete
Promising to see a WAA wing of sorts developing in an E-W fashion south of Brandon.
Incredible lightning show to my west/southwest here in Altona.ReplyDelete
Line appears to be strengthening.
Yeah.. so far no sign of splitting with the southern end becoming better organized and bowing out. A really fast moving, forward propagating MCS.. could be some damaging straight-line wind with that segment of the line.ReplyDelete
If storms continue advecting along the mean 300-850 hPa flow they should arrive in Winnipeg within an hour.. with likely the worse part of storms passing south and east of the city
in last few radar frames the southern end of the line has clearly started curving more to the east as the propagation vector (opposite the low-level inflow) is becoming dominant. The strongest cells will likely graze the border and move due east.. lets see what we wake up to ;)ReplyDelete
At the very least Winnipeg should get a good light show and some gusty winds!!ReplyDelete
It sure looks like it Daniel P. Low, scudding clouds coming in from the southeast, and great light show looking west-southwest from south central Winnipeg. Trying to get the cats in...they haven't heard anything this loud since those two jets kept buzzing us last Friday eve :)ReplyDelete
Warning is up for the city. That line is moving fast. E-NE it looks like. Staying up for this...it's been too long.ReplyDelete
Big storm heading right into the city! Warnings now issued!!!
Very heavy rain here in St James!!ReplyDelete
Good light show, good rain to help out the lawn, that's what I was after.ReplyDelete
This storm is definitely welcome to me. The plants are loving this I bet. Not to mention, the Seine River just past my house here looks about 2-3 feet lower than average. I don't believe I've seen it that low before. This rain should go a good ways to help restore water levels, hopefully at least.ReplyDelete
Weakened as it got into central city and now, just a nice t-shower. Was expecting a "rain first, wind after" set-up. Agreed that we need the rain though. Cats just stared at the open door, didn't want to come in. I think they're onto something:) G'night.ReplyDelete
Rob picked up 20 mm of rain.ReplyDelete
That's a good soaking!!!
Picked up only 10 mm of rain in South St. Vital!ReplyDelete
Wow I only got 7 mm where I am in south end. I had a feeling other parts of the city got more ;)ReplyDelete
Daniel..(Yawnnnin). What did I miss... Oh that. Rose at 2 to see a fantastic show in the south and southeast..ReplyDelete
Disappointed..Only enough rain for an average 2011 summer month or 2 mos if you live in Charleswood.lol
Only 7.6mm here in Transcona. Sounds like other areas got a fair bit more.ReplyDelete
Daniel, read the EC forceasting rules. A 50/50 chance isn't allowed. It goes from 40% to 60%. No sitting on the fence! LOL :)ReplyDelete
Yawn is right lol.. yeah severe parameters split off and moved due east across the northern tier of counties in N Dakota (ofcourse just before it hit Winnipeg ;) giving 40-70 mm of rain, and wind gusts near 100 km/h between Hallock and Grand Forks from the looks of things. Northern end weakened and continued moving NE.. giving us those generic showers and tshowers. Really not enough to make much of a dent in our moisture deficit for a lot of areas :(ReplyDelete
Hart Mountain, up on the Porcupine Hills north of Swan River, received 110 mm last evening and overnight. It appears to be the highest amount recorded in the province.ReplyDelete
Hey how come starting in 2008 Winnipeg airport stopped reporting thunderstorms and other weather elements under the weather column in the historical hourly data reports? Instead of thunderstorms it just says "rain" or "moderate rain". If it isn't raining then it just says nothing at all. I feel this is almost a qualitative step back since it may be useful to look back and see what days it stormed (I know there are students that would rely on that data for their studies and probably other resources as well. How are you suppose to distinguish between a day where it just rained or a day it thunderstormed but it just labels it as rain?)ReplyDelete
The hourly reports you're looking at are from the "YWG Richardson AWOS" site which only has the raw automated data (no sky condition or weather elements) If you look at the "YWG Richardson Intl A" hourly data, it will have the actual weather elements for the hour taken by the weather observer including thunderstorms. I know.. it's VERY confusing and not at all intuitive.. but that's the problem when they changed the EC site to a NAVCANADA site in July 2008.
An easy way to get the full hourly data is to change the YWG station ID in the URL from 47407 (AWOS) to 3698 (Intl A)
Or, under navigation options, select "nearby stations with data", then choose WINNIPEG RICHARDSON INTL A hourly data.
Hope that helps..
Winnipeg airport picked up 15 mm overnight, with 13 mm at the Forks. My Davis station measured almost 20 mm, although my standard gauge in the backyard had 17 mm. City of Winnipeg rainfall map shows a good swath of 10-20 mm over western and northern Winnipeg, with 5-10 mm over the southeast part of the city.ReplyDelete
Looking at the summer precip totals, YWG airport recorded 93 mm of rain for the 3 months of JJA, driest since 2006 (91.5 mm) and 5th driest on record since 1873. Normal summer precip is 235 mm, so we had a 140 mm precip deficit, or about 40% of normal summer rainfall.ReplyDelete
At my site, I recorded a summer total of 105 mm.
Did you hear that New Orleans is set to recieve a Potential 15 -20 inches of rain this long weekend??? That's if that storm is stuck in the slack flow!!!
The GEM Global shows 383 mm (about 15 inches) for New Orleans by Monday morning. Who wants to drive down there and rescue Angelina?ReplyDelete