Wednesday, May 16, 2012
Showers/thunderstorms possible Friday into Friday night.. improving weather for holiday weekend..
High pressure over southern Manitoba today will give way to an increasing southeast flow ahead of a large scale storm system that will be developing over the western US plains/Rockies over the next couple of days. This system will draw increasingly more humid air from the southern US Plains by the end of the week, along with warmer air. This will lead to an increased chance of showers and thunderstorms over southern MB Friday, first ahead of the warm front in advance of the system, then along the cold front later Friday into Friday night. There is the potential for locally strong thunderstorms by Friday night, however that will depend largely on how much humidity can be drawn up with this system, and how much cloud will be around with the warm front. Cloudy and unsettled weather Saturday is expected to clear out by Sunday along with cooler temperatures, before a generally pleasant end to the holiday weekend with sunny skies and near normal temperatures Monday.
Subscribe to:
Post Comments (Atom)
Any local frost this am?
ReplyDeleteJim..
ReplyDeleteThere was extensive frost outside the city especially to our north and east.. lots of temps in the -1 to -3C range, even some -4C readings. Here at my place in Charleswood, I had a low of -0.1C, with a light frost on the grass, but mostly dew. Looks like most places in the city escaped frost, especially downtown, although there was likely patchy frost in sheltered areas given the clear skies and light winds last night.
CBC Winnipeg seems to be alone in forecasting frontal/low passage over Winnipeg already by Friday afternoon (lower temps and wind shift by that time). It will be interesting to watch it play out as timing could make a difference with possible severe weather.
ReplyDeleteA high of 31 C and showers for Friday!!! Can you say STEAMBATH?!!
ReplyDeleteI do not buy the RGEM solution for Friday.. the model is once again having problems resolving surface pressure pattern in a split flow aloft. Namely it is too strong with low pressure over Saskatchewan and Manitoba, and too far north with warm front.
ReplyDeleteAmerican models show energy consolidating around southern stream wave and have low pressure slumping towards S Dakota. NAM shows warm front to our south on Friday before lifting it into SE Manitoba. Highs in the midtwenties are more realistic with posible clouds and NE winds. Juicy air will stay near int'l border.
I would expect elevated convection to affect Winnipeg and points SE Friday overnite and early Saturday as LLJ gets going. Convection may be limited in the warm sector inspite of extreme instability due capping and lack of shear. What are your thoughts Rob?
Daniel
Oh. CBC just changed the forecast from this morning's version. Bumped Friday up by 4C and delayed the showers and wind shift.
ReplyDeletePlus with the KMVX radar going down for the dual-pol upgrade, this'll be a fun one.
ReplyDelete29 and 32 C now being forecast by EC for tomorrow and Friday. NAM has shifted a little bit further north with the warm front during the period. 850 hPa temps reach 15 C by very late tomorrow, and 18 C by Friday evening. We'll see how much mixing can occur north of the surface boundary with ESE flow ..but I would say 26 C will do for tomorrow.
ReplyDeleteFriday will be very tricky, with warm front bubbling up into southern RRV. Models seem to go berserk with warming.. NAM even gives super-adiabatic lapse rates by mid-afternoon over us. However, front slumps south by evening putting us in ENE flow. That, combined with potential for cloud cover along the front, could keep temperatures in the mid to upper twenties range for Winnipeg. Temperatures at Grand Forks, Fargo, and possibly the far southern RRV could reach as high as 33-35 C.
Models show dewpoints eventually rising to 15-17 C for us.. again we'll have to see how much moisture will return and can pool north of the warm front.
Still looks like elevated convection setting up overnite
into Saturday morning along LLJ and surface trough. Dry-slot moves in later in the day..
Daniel
Daniel..
ReplyDeleteYes, looking like a potentially active day Friday.. as you mention, NAM has shifted warm front further north putting Winnipeg just into the warm sector with highs of 31C, and dewpoints climbing to 15C with SBCAPEs over 2000 j/kg by mid/late afternoon. SPC not buying that rapid a dewpoint increase as dewpoints are still quite low through the central plains. As you say, warm front will lie very close to Winnipeg/TransCanada with a potential for cooler temps over us, and better chance of warmer temps to our south. Even if we don't get completely in the warm sector, potential for warm frontal storms remains. We'll see what tonight's models say..
NAM has shifted warm front a little further south again on tonight's run.. with a high of 27C and overunning tstorms by evening. RGEM on the other hand pushes warm front north of Winnipeg, with highs soaring up to 33C. Curiously, dewpoints of only 7-8C are forecast with little in the way of thunderstorm activity. Needless to say, a very tricky forecast for Winnipeg but I'd be leaning more towards the NAM solution.
ReplyDeleteI was just going to mention it Rob. That solution also has support from GFS with 26/27 C on Friday. I agree.. based on the American guidance and past experience with these set-ups, I think that we will end up on the cooler side of things.
ReplyDeleteDaniel
Overnight RGEM run has pushed warm front further south along the US border Friday, with light northeast surface winds forecast for Winnipeg.. yet UMOS guidance still suggesting a high of 32C for Winnipeg which doesn't seem likely in that scenario. All models now indicating warm front will lie along the US border Friday, with ensembles showing a wide spread in highs for Winnipeg with majority of members clustered between 20-27C. 30C temps more likely towards US border and south.
ReplyDeleteTstm potential will depend on how much moisture can be drawn up from the southern Plains overnight into Friday, but current analysis and outlooks show modest moisture transport with dewpoints in the low teens at best over RRV/SE MB Friday. Best chance for stronger tstms will be over southern RRV and SE MB later Friday into Friday evening closer to where low level jet intersects warm front.
Latest runs from all the main models continue to show that Winnipeg won't make it into the warm sector Friday, with warm front lying to our south and east. Areas along the Intl border and far SE MB have the best chance of getting into the warmest air (30C) but chances are less likely further north and west. UMOS continues to show warm bias for Winnipeg projecting a high of 31C by noon, even through surface winds are forecast to be from the north or northeast. Not likely.
ReplyDeleteSo rob does that mean we won't feel hot and humid on Friday? Is it a possibilty?
ReplyDeleteI mean today's high of 29 C is not to shabby. Looking forward to the thunderstorm tomorrow :)
ReplyDeleteMike..
ReplyDeleteIt will be still be warm and more humid than today.. but I don't think it will be hot and humid by summer standards, at least in Winnipeg. If we can stay sunny most of the day, then we should get to 27-28C even north of the warm front, but dewpoints will be around 13C tomorrow afternoon.. higher than today, but not as sticky or muggy as dewpoints of 17C or higher would feel like. Best bet for 30C temperatures tomorrow will be from Morris south and east. There will likely be a sharp gradient in temperatures in the RRV Friday ranging from the low 20s near Lake Winnipeg to low 30s near the US border based on current projections of the warm front tomorrow.
Surface low somewhere just north of Brandon with warm front extending ESE to Emerson. 850 hPa temps only at 13 C per model soundings, but good mixing down from that level, and full sun combined with dry top soils allowing for strong heating (superadiabatic lapse rates below 925 hPa). Its making for a beautiful day with the lighter winds this afternoon.. and may end up being warmer than tomorrow.
ReplyDeleteLow pressure focuses further south in the Dakotas overnite and warm frontal trough slumps SE.. we switch to NE flow sometime before dawn. Highs north of the warm front tomorrow dependent on how much sun we get. The dry topsoil would generate a lot of surface heating, getting us into the high twenties again like Rob mentioned.
In terms of convection, any focus for severe thunderstorms will be off to SE, tapping better instability and persistent LLJ late Friday. Models show an area of post-frontal precipitation on Saturday, probably related to mid-level frontogenesis and dynamics from upper trough. Instability will be limited but hopefully we can get some rain out of it..
Daniel
First 30c of the year at my place! Maximum of 30.3c late today according to my backyard station.
ReplyDelete29.5 at the airport so far, Rob...and looks like that will be the max for the day.
ReplyDeleteThanks Dan.. so close!
ReplyDeleteInteresting to see that thunderstorm complex track along the ND/MB border this evening.. yet no radar from Grand Forks OR Woodlands to monitor them!
Anyone know when the Woodlands radar will be up? Be nice to have radar coverage for tomorrows storms...
ReplyDeleteInteresting. Environment Canada has used the term THUNDERSHOWERS instead of the normal ThunderSTORMS for tonight's forecast!!
ReplyDeleteWell defined warm front extending from surface low over northern South Dakota through Grand Forks into Kenora. Surface dewpoints in warm sector marginal in the 11-14c range with strong capping, little chance for severe surface based storms today except perhaps along cold front through ND later today with better forcing and weakeniing cap. Warm front not expected to get much further north today, progressing a bit northeast so that only extreme SE MB would get into the true warm sector. By this evening, elevated tstorms along warm front as well as any cold frontal storms that pop over ND possible over SE MB with a ithreat of scattered weaker thunderstorms elsewhere over RRV.
ReplyDeleteWinds are now out of the north, clouds have rolled in, and that high of 29C is now looking like a long shot!!
ReplyDeleteOnly 9 C in Dauphin with heavy rainshowers!!!
Do you think Winnipeg will still experience thunderstorms tonight? If so what about the XWL Woodlands Radar?
ReplyDeleteLucky for you Mike (and everyone else), XWL's up again.
ReplyDeleteIn the Grand Forks NWS' hazardous weather statement, it looks like KMVX won't be up as they're telling trained spotters to be ready even though it doesn't look like much will happen.
Yes, quite the contrast in temperatures from northwest to southeast across southern MB this afternoon. Sprague the hot spot at 27C south of the warm front as of 1 pm while it's only 14C at Portage and 10C at Dauphin. Click on my name for nice surface temperature analysis. Winnipeg will struggle to 25C this afternoon with northerly winds tapping that cooler air to the north along with the increasing high clouds (so much for UMOS's 31C by 1 pm!). I still think we'll see some showers and embedded tstorms tonight from the convection out to the west moving in here, but any heavier tstorms will be confined to SE MB closer to the warm front and warmer air.
ReplyDeleteDid the cold front just go through Winnipeg, with falling temps and gusting north winds???
ReplyDeleteHi from Grand Forks
ReplyDeleteThe techs are finishing up the radar work and testing some things this afternoon-evening. If all goes well come be up sometime Saturday.. WFO Duluth has had some radar troubles after the install.
94 F in Fargo ND this afternoon!!
ReplyDeleteAnonymous... It's more like a retreating warm front than a cold front, but the results are similar. We have an increasing northerly wind tapping cooler air fom the north, which is pushing the warm front further southeast. Note that Pinawa dropped fom 30c at 2 pm to 24c at 3 pm as the warm front was pushed southeast by the cooler air.
ReplyDeleteLooked at all forecasts, thunderstorm potential still remains in the SE and here in winnipeg. Anyone know what is expected?
ReplyDeleteSoutheastern tip of MB showing SBCAPE 1500 - 3000kjs and Lift Index a -4 & -5. Enough for a little boomer maybe?
ReplyDeleteRob!
ReplyDelete5:00 pm readings:
95 F in Fargo ND
59 F in Minot ND
LOL!!
Thunderstorms have fired to the northeast of Winnipeg!!!
ReplyDeletePlus now some stuff firing up SW of the city!
ReplyDeleteShowers just starting in Charleswood.
ReplyDeleteBoth the Bird's Hill lightning (http://www.bezte.ca/weather/lightning/stormvue.html) and the EC lightning don't show any or at least not much activity to the SW, but on the radar it's showing some yellows. Probably some light to moderate rain for now.
ReplyDeleteThunder in Charleswood.. Rain getting heavier..
ReplyDeleteTry this lightning detection Connor:
ReplyDeletehttp://www.intellicast.com/Storm/Severe/Lightning.aspx
Oh yeah, that definitely shows activity.
ReplyDeleteFirst rumble across the Assiniboine.
ReplyDeleteHeavy downpour in Charleswood now with thunder and lightning...
ReplyDeleteMassive downpour... Rain rate of 103 mm/h!!
ReplyDeleteNice storm heading toward downtown!!
ReplyDeleteDownpour passed the river, visibility reducing!
ReplyDeleteLess than ~3 km visibility,
ReplyDeleteNice storm has just passed through St.James on Beaverbend Crescent.
ReplyDeleteinb4 Rob says "EC Y U NO ISSUE SWS?!"
ReplyDeleteYou know something's hit downtown when the tweet volume mentioning WPG goes through the roof.
ReplyDeletesmall hail in central Winnipeg
ReplyDeleteReports of some hail!
ReplyDeleteLOL, Anonymous and I posted those comments just seconds after each other.
ReplyDeleteTwitter images confirm hail in downtown Winnipeg.. looks about pea to small marble size, enough to accumulate in some areas..
ReplyDeleteAny hail across the river Rob?
ReplyDeletewow 15 mm at your station Rob! Only a couple drops in River Park South so far lol.
ReplyDeleteSEVERE THUNDERSTORM WARNING FOR:
ReplyDelete=NEW= R.M. OF WEST ST. PAUL INCLUDING MIDDLECHURCH AND RIVERSIDE
=NEW= R.M. OF EAST ST. PAUL INCLUDING BIRDS HILL
CITY OF WINNIPEG
R.M. OF ST. ANDREWS INCLUDING SELKIRK LOCKPORT AND CLANDEBOYE
R.M. OF ST. CLEMENTS INCLUDING LIBAU.
AT 8:30 PM QUARTER-SIZED HAIL WAS REPORTED FROM A SEVERE
THUNDERSTORM ON THE NORTH END OF WINNIPEG. THIS CELL IS HEADING
TO THE NORTHEAST AT 30 KM/H.
(if the formatting screws up somehow, http://kamala.cod.edu/Canada/latest.wwcn11.CWWG.html)
dime size hail when that deluge came through...WOW!
ReplyDeleteQuite a sustained downpour in central Winnipeg, easily up to 25-30 mm... with more on the way by the looks of it. Elevated convection associated with frontogenesis between 700 and 850 hPa.
ReplyDeleteDaniel
No hail at my place.. but I'm getting a second wave of storms now.. over 20 mm of heavy rain since 8 pm.
ReplyDeletetorrential rain starting up again...
ReplyDeleteDaniel
also getting a few cloud to ground lightning strikes..
ReplyDeleteRob!
ReplyDeleteCheck out your facebook page for the storm from my place!!
27 mm at my place since 8 pm with a max rain rate of 133 mm/hr at 8:11 pm.. things are starting to settle down now while more storms fire up to our southeast. 30 mm of rain recorded at U of W, 32 mm at E St Paul with pea-marble hail downtown. These storms were definitely more intense than I was expecting here.. was thinking more so to our southeast. Nice surprise!
ReplyDeleteHello Everyone, been busy tweeting on Twitter. At around 8pm the skies darkened at our place on beaverbend Crescent, some rolling thunder at the time when the storms popped up on Radar. Then it really got intense, got to the point that our recycling bins were filling up with water. Heaviest I've seen in a long time. It definitely had a ton of lightning. I guess we had 25mm of rain in st.james overall, Can't believe how quick it came in.
ReplyDeleteThe electrical activity is definitely showing up on my detector here in Regina.
ReplyDeletehttp://users.accesscomm.ca/saskweather/lightning/svngx/StormVueNG.swf
WeatherBug is another good resource.
Send some of it our way. :-)
Thanks for the links Dean.. yeah, a pretty decent round of storms for us, especially for being in the cooler air with temps in the mid teens!
ReplyDelete