Tuesday, May 22, 2012
Another round of showers and thunderstorms tonight.. locally heavy rain and hail possible
Another round of showers and thunderstorms is on tap for southern Manitoba tonight as a low pressure system over the Dakotas pushes a warm front towards the Manitoba border. Warm and increasingly humid air will spread up through the Dakotas today while cooler air remains entrenched over the southern Prairies. The clash of airmasses and favourable dynamics aloft will result in widespread showers and embedded thunderstorms developing later today into this evening across southern Manitoba. The best chance of heaviest thunderstorms will be over the Red River valley and southeast MB where strong to locally severe thunderstorms from the Dakotas will be tracking across the border by this evening, as well as developing along the warm front. Main threat with these storms will be large hail and strong winds, with areas of very heavy rain (25-50 mm) possible. A secondary area of heavy rain is also likely through the Interlake regions tonight into Wednesday as an upper low over southern Saskatchewan tracks slowly eastward into the Manitoba lakes region. Conditions are expected to dry out Thursday and Friday for most of southern Manitoba (rain still possible near Ontario border Thursday) before more unsettled weather moves in for the weekend. All in all, a generally unsettled week ahead as we get into a more stormy and variable pattern.
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https://img.skitch.com/20120522-k9bndcex3yrk7qgkuxg9j4ckp7.png
ReplyDeleteLate this afternoon into the evening, we'll have decent moisture available aloft at all levels. A sharp thermal ridge at 850mb (red) will be positioned near the ND/MN border and arc NW over the SW RRV into SW MB, with an associated 40-50kt LLJ. It looks like the 700mb (orange) thermal ridge will push ahead, destabilizing the mid-levels early in the evening. The left exit of a 30kt jet at 700mb looks to rest over the Manitoba RRV by early evening. This will all be supported by a strengthening 40-50kt jet at 500mb arcing across Southern Manitoba from the Pilot Mound region towards Pinawa. Deep lift will be present with the right entrance of a 60kt jet over SW MB.
[...]
All this to say that...thunderstorms will likely fire in ND tomorrow afternoon along the surface cold front as it advances eastwards. As they progress, upper-level features will begin to align and intensify to help discrete-cell storms grow upscale into a strong, linear feature that will rapidly expand and push northwards, supported by deep lift and moisture provided by the left exit regions of lower-level jets and right entrance regions of upper-level jets. Mid-level temperature profiles will destabilize later in the the afternoon/early evening, further supporting the evolution of a nocturnal thunderstorm complex.
All that being said, this ends up being my expected risk area for today's storms:
https://img.skitch.com/20120522-d19d1getmyyncg2sjwugm3g72h.png
You can read an even more thorough discussion over in the comments on my blog: http://aweathermoment.tumblr.com/post/23478088028/stormy-weather-to-return-to-southern-manitoba#comment-535061119
How do you feel about the areas I've covered in my slight risk of a severe storm graphic, Rob?
Looks good Brad.. I agree with your slight risk area. Main threat for us will again be heavy rain and hail much like Friday. Interesting to note that the warm front today is oriented almost exactly like it was Friday.. from Emerson to Kenora area. Tight thermal gradient across this boundary with 30C plus temps to the south, and 20C to the north. Dewpoints are a little juicier in the Dakotas with this system (mid teens) compared with Friday's event (low teens), so there should be a little more energy and moisture available with the convection later today. Good thing GFK radar is back up, should be interesting later on today!
ReplyDeleteGetting some real good vibes about this system. SPC has us in a 2% tornado, 15% wind, and 30% hail risk tonight.
ReplyDeleteSome of the simulated reflectivites I've seen are showing some sort of linear system moving through late evening/overnight. That would fall in line with Brad's outlook.
Two potential threat areas with convection later today.. east-west band of training thunderstorms developing along and ahead of the warm front with elevated instability and LLJ (roughly along and north of the TransCanada corridor) with heavy rain as the main threat.. then cold frontal storms developing over central ND and propagating newd across RRV and SE MB with hail and wind as main threat later this evening..
ReplyDeleteI will say this again. Any severe storm set-up in May is a bonus. Even if we just get some lightning and rain, I'll be happy.
ReplyDeleteSPC has actually bumped up severe probs for us in the latest update. They have a 5% tornado, 30% wind, and 30% hail risk extending into southern Manitoba. Interesting.
Central ND is being monitored for a WW by the SPC: http://www.spc.noaa.gov/products/md/md0869.html
ReplyDeleteLooks like we have a tornado watch for ND. http://www.spc.noaa.gov/products/watch/ww0290.html
ReplyDeleteWaiting for the fireworks to start south of the border. Meanwhile, looks like Winnipeg/RRV may be safe for a few hours early this evening before the showers/tstorms move up from the Dakotas later this evening and overnight. Hopefully daughter can get her baseball game in before the skies open up again..
ReplyDeleteHaven't had much time to look at models.. but as Rob alluded to, progged QPF fields hint at a split in precipitation as we often see.
ReplyDeleteSome sort of MCS looks to develop with a southern stream wave and nose of LLJ, and travels ENE along the main instability gradient. My feeling is that this system may trend more towards the east as LLJ ramps up and propogation vector increases (south into the LLJ).. potentially brushing us.
Meanwhile a developing trowal and area of deformation will support another area of significnat rain as parent trough closes off. Main focus will be off to our north and west. Questions are how much precipitation will occur between these areas and the track of any MCS that forms..
Daniel
Daniel,
ReplyDeleteAlways look forward to your posts.
I feel like I'm in a great spot here in Altona. Most models bring, at least, the northern portion of an MCS through the Pembina Valley and Red River Valley.
Don't be shocked to see the odd storm or two pop up near the warm front this evening. Some pretty good WAA should get going, at some point.
Intense convection in southeastern Saskatchewan right now with some hints at development in northwestern North Dakota.
Thanks Derek,
ReplyDeleteYeah it looks like the southern RRV will have a good shot for at least some strong to possibly even severe convection tonite.. will be intersting to see.
Daniel
Warned cell approaching Estevan.. marble size hail possible. Note however that Foxwarren radar looks like it's running hot again.. radar returns way overdone compared to neighbouring radars.
ReplyDeleteReed Timmer has intercepted multiple tornadoes on that storm affecting Estevan.
ReplyDeleteLooks like that storm is really taking advantage of the warm front and the enhanced helicity/shear.
@Derek
ReplyDeleteSaw it on the stream. At least 5 distinct tornadoes have touched down where he's been following. Not long-lasting, but certainly worth warning.
That must sound impressive! Too bad that the stream's currently dead...
ReplyDeleteI guess it's too late for a warning lol, worst of the storm moved south of the border.
ReplyDeleteStill might possibly be worthy of a tornado watch up here though.
ReplyDeleteAgreed on the watch.
ReplyDeleteWould expect a watch of some sort to be issued by EC for SW MB shortly.
ReplyDeleteInteresting to see a small convective cell has popped to the east of Grafton, ND.
SEVERE THUNDERSTORM WATCH FOR:
ReplyDelete=NEW= MELITA - BOISSEVAIN - TURTLE MOUNTAIN PROVINCIAL PARK.
AN AREA OF INTENSE THUNDERSTORMS IN NORTHERN NORTH DAKOTA IS
MOVING SLOWLY EAST-NORTHEASTWARD AND MAY CROSS INTO EXTREME
SOUTHWESTERN MANITOBA THIS EVENING.
THIS IS AN ALERT TO THE POTENTIAL DEVELOPMENT OF SEVERE
THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS.
MONITOR WEATHER CONDITIONS..LISTEN FOR UPDATED STATEMENTS.
IF THREATENING WEATHER APPROACHES TAKE IMMEDIATE SAFETY
PRECAUTIONS.
Disappointing...you'd think EC would issue it for a wider area...
ReplyDeleteIf need be, they'll extend it east later this evening.
ReplyDeleteHopefully we'll see some serious rain, the flooded basement and underpass type.
ReplyDeleteGive me a lightning show and I'm happy.
ReplyDeleteSome cells firing up near the PLP area.
ReplyDeleteHere we go! Some rain firing up to the SW of the city. Any bets on a repeat of Friday?
ReplyDeleteAlso seeing some attempts to the south and west of that.
ReplyDeletePretty intense cell attempting to enter SW MB right now.
More strong to severe stuff tracking NNE in southern ND right now.
Some sprinkles in NW WPG, no rumbles yet.
ReplyDeleteScratch that, just got thunder.
ReplyDeleteSurprised EC hasn't issued a warning in the extreme sw MB, Minot radar showing 60+dBZ
ReplyDeleteWhere is all the storms?
ReplyDeleteHi Rob,
ReplyDeleteThis will come in the middle of all the posts about this evening's weather. I am wondering about the time shown on the IR Satellite Image on Rob's Obs - is that CDT? Also the time shown on the Current Radar is UTC. What is the adjustment to convert that to CDT?
My son uses these images all the time to help him with his outdoor business.
Mike..
ReplyDeleteRadar will show you where all the storms are. Line of cells has popped up north and east of Winnipeg ahead of the warm front. Then we have a few stronger tstorm cells over SW MB and the western RRV moving to the NNE. Finally a cluster of strong to severe tstorms over eastern ND spreading newd possibly to affect southern RRV and SE MB.
Winnipeg may actually dodge most of these storms as they skirt to our southeast, and west. However I think we should see something by midnight or early overnight with a band of showers and embedded thunderstorms. However, it's quite possible Winnipeg may miss the heaviest activity this time around.
JoeL..
ReplyDeleteBoth satellite and radar images are in UTC. Subtract 5 hrs to get CDT. (6 hrs for CST)
Definitely an interesting situation that's developed.
ReplyDeleteExtensive thunderstorms over SW Manitoba continue to rumble northeastwards. Developing earlier in the day in an area with plenty of sunshine, instability, and a good moisture feed, these storms organized quickly and have grown into a multicellular cluster that will go all night.
Convection in North Dakota initiated significantly further south and east than expected, allowing it to tap into even more instability and moisture than if it were to fire further north. That's allowed that storm to just explode; it's anvil now covers almost 1/3rd of North Dakota.
Unfortunately, all that air that's going up has to come down, and unfortunately that's often downwind. You can watch the clouds melt away as the anvil grows on the satellite image, and that subsidence will be an extra force that any storms that want to fire further north will have to battle against. One small cell heading towards Emerson has tried to go, but simply can't break through the cap.
With the way things are, I think my outlook has been fairly good. The complex over SW MB will push NE and (probably) end up missing the city of Winnipeg. The storms over S. ND will continue to push NNE and into SE MB overnight. There's certainly a non-zero chance that storms may fill in between the two systems, but at the moment it would not be a shock if storms ended up passing Winnipeg to the North and to the East.
Incredible lightning show right now in Altona
ReplyDeleteAnd there we go. It's filling in quite nicely along Highway 13/3/32 from the Trans-Canada Hwy. to the Int'l Border. Plenty of lightning in those storms. Will slowly push eastwards with the LLJ. Should see a bit of a light show move through in the next 1-3 hours.
ReplyDeleteYep.. Lots of in cloud lightning to my west. Line growing nicely.. Should see something here by 1 am or so...
ReplyDeleteCorrection... Between midnight and 1 am..
ReplyDeleteWow.. Lightning on western horizon is almost continuous now.
ReplyDeleteLots of attenuation on the Woodlands radar display from EC, as that line tries to build. Leading edge looks like its nearing the West Perimeter.
ReplyDeleteCould see some big wind gusts when the first showers hit shortly.
ReplyDeleteWow incredible light show with that first round. Can't believe my eyes there's a second round coming.
ReplyDeleteThanks Rob. Now that I know that I can see that both the radar and the satellite are showing what has happened over the last few hours. What I would like to know is there any visual representation of what is likely to occur over the coming few hours? That's the information that my son really needs.
ReplyDeleteOnly 3 mm of rain last night at my place with the thunderstorms that passed through after midnight. Nice light show but main action went generally just north and east of the city, with amounts of 10-20 mm in places like Oakbank, Beasejour and Gimli. Radar accumulation product from Woodlands shows main swath was from Ile Des Chenes area through Oakbank and Beasejour up to Milner Ridge with pockets of 25-50 mm noted (assuming no hail contamination) Little or no rain over the southern RRV which basically missed out on the storms. Secondary area of heavier rain over Duck Mtn area with 25-50 mm towards the SK border.
ReplyDeleteJoeL..
ReplyDeleteYou can access a forecast IR satellite image for the Prairies by clicking on the "IR satellite" icon on my main webpage, then scrolling down to "48hr IR satellite forecast" There are links to IR satellite imagery for the next 48 hrs from the Canadian GEM model, which basically shows the amount of total water vapour in the air. Loop to 48 hrs. Time in UTC. It's just model data though, so treat it with a degree of caution. But it can give you a good idea of trends and timing of clouds.
For radar, you can try Weather Network's "futurecast" of radar on their radar imagery (available on my radar page) It just takes current radar and "moves" it forward a few hours based on current storm motion. Note however, that it cannot forecast future trends (like intensification or decaying of cells) so beware of its limitations. But it can give you a fairly good sense of storm motion and precip timing if things are behaving.
Also, you can also take a look at graphs of model data for things like temperature, precipitation, clouds, etc at select points. GEM model graphical data for Winnipeg available under the Winnipeg forecast icon (12 hr, 48 hr, 6 day, etc) from SpotWx.com Links also for NAM, GFS and European model data shown. These will give you a general sense of precip, temperature, humidity, wind and cloud trends over the next few hours or days (strictly model data though, so again.. treat with caution)
Hope that helps!
we are hosting an event at my school today, and have postponed it due to possible thunderstorms? Do you guys think that we will be safe from them at 11:30am to 1:30PM?
ReplyDeleteI think you're pretty safe today, Mike. If we get anything today it'll be showers in the late afternoon. Maaaaaybe a strike of lightning. Should be a nice lunch hour :-)
ReplyDeleteRob, did you notice the little "heat burst" overnight after the storms went though? https://img.skitch.com/20120523-xxr92a3jta8dq9p4ek8jyasqh6.png
ReplyDeleteYeah, temperature at my site popped up to 18.6C around 4 am before dropping to a low of 13C early this morning. I think it was due to a wind shift into the SW that briefly tapped into the warm sector. Note that the dewpoint also popped up to 17C at that time. A true heat burst would be associated with a sudden rise in temperature as well as a dramatic drying of the dewpoint, usually just preceding a thunderstorm.
ReplyDeleteAgreed; I used the quotes liberally :)
ReplyDeleteYikes.. don't look now, but models indicating some snow over the Duck and Riding Mtns and higher elevations of SE SK Thursday night into early Friday. Don't want to see that..
ReplyDeleteMajor cooldown for Friday into Saturday as long wave trof moves over Prairies, with northwest winds behind departing low Thursday advecting chilly air from the north into southern Prairies. As mentioned, progs show it will get cold enough for rain to change to snow over higher elevations of western MB and eastern SK Thursday night into early Friday. Will need to keep an eye on frost and freeze potential for Winnipeg and RRV Saturday morning.. hopefully things will stay cloudy enough Friday night to prevent temps from dropping too much after a chilly day Friday, but gardeners beware, potential for frost Friday night into early Saturday. Saturday looks dry for the most part, but another well defined system and warm front with large scale push of warm air from the south will bring another round of showers and thunderstorms into southern MB later Saturday into Sunday with potential for heavy rainfall yet again (of course, it's the Teddy Bear picnic Sunday!). Staying generally cool and unsettled into early next week. Not much in the way of sunshine and warm temperatures for the next little while unfortunately.
ReplyDeleteIs it gonna rain the heaviest/ all day sunday or will it taper off in the aft sunday?
ReplyDeleteToo early to say.. looks like showers and possible tstorms move in Saturday night into Sunday morning, tapering off by evening.. so it's possible there *could* be a break in the rain Sunday afternoon if system is a little faster. However, system is still organizing and is a few days away, so timing and distribution of precipitation, especially convective in nature, is highly speculative at this point.
ReplyDelete