Thursday, July 16, 2009

Fall like weather to give way to nice weekend..

It’s a cool wet July morning out there with overcast skies, rain and temperatures only around 9C.. making it feel more like fall than mid summer.  A low pressure system over northern Ontario is bringing a gusty northwest flow of unseasonably cool air over southern MB today, along with occasional rain and drizzle. The air is even cool enough to generate enhanced bands of lake effect rainshowers to the southeast of Lakes Manitoba and Winnipeg today. The clouds and rain will keep temperatures only in the low teens at best today.. some 10-15 degrees below the normal high of 27C for mid July, the warmest time of the year in southern MB. Cloudy cool weather will persist tonight into Friday morning before skies begin to clear out by afternoon or evening as a ridge of high pressure over Saskatchewan builds into the province. This ridge will bring a much nicer weekend for us with sunny skies and more seasonable temperatures in the mid 20s.


  1. Chris - Windsor Park7:29 AM, July 16, 2009

    Just thought I would mention this for everyone who is a little depressed about this weather. If July ended today, it would be the coldest July ever recorded. Even though the 2nd half of July is supposed to be warmer, it will be interesting to see if its enough to put us in the above normal category for the month of July. I'm thinking we will have to hit 30 or above for at least a couple days to achieve this.
    Good news from David Phillips (I think thats the name of the head climatologist at EC): its supposed to be warmer than normal from now (not including today or tomorrow) until mid August.
    Wait.....isn't this the same guy who said we would have an unusually warm summer in its entirety?
    Thoughts on the newest model runs?

  2. Current GEM-GLB I think is a little too strong on the ridging/warming moving into the prairies. I'll be surprised if we get over 26 degrees in the next week. *sigh*

    Ridging on current models is sharp, more like a default ridge between two large upper vorticies; waiting to see the upper high building back northward.

  3. Models show highs in the mid twenties for Saturday and the low thirties for Sunday. They are also showing a decent risk of severe storms - with possible tornadoes, for Sunday. Looks like a cool-down after that.

  4. If you believe the GFS,it doesn't look like any sustained heat through next week. We get a nice warmup this weekend (well, near normal anyways) then a cold front comes through Monday. Today's NAM/GFS have sped up that front from earlier runs, which had it coming through late Monday. Latest Canadian GLB also has it coming through the day Monday, so expect to see that sunny forecast for Monday change. After that, we cool down for the rest of the week with temperatures below normal (low 20s).

    Latest guidance also hinting at the possibility of warm frontal convection Saturday night over us into the Interlake.. so our sunny dry weekend may be interrupted by some cloud and tstorms.. hopefully they stay north of us if any.

    At this rate, it does look like July will end up below normal temperature wise.. whether it'll be the coolest July on record remains to be seen. As of the 15th, Winnipeg airport had a monthly mean of 15.8C (mainly due to some chilly nighttime lows in the single digits). Our two coolest Julys on record came after major volcanic eruptions the summer before.. 1884 with a mean of 15.4C (after Krakatoa) and 1992 with a mean of 15.9C (after Pinatubo)

  5. Rob
    Some critics of the Alberta Tar Sands have indicated that they easily represent accumulatively the equivalent Sulphur emissions of the worst volcanic eruptions. The Sask. Leg. has discussed it and reports of significant acidification in Lakes downwind (as we are)..

    Should Manitobans expect the same long term results as major Volcanic activity...cooling weather patterns, wetland methane release reductions and more acidic Lakes etc. ??

    We have some of that that from the smelters in Thompson and Flin Flon. (Acid Rain problem and acidic downwind lakes)

    Is this why the USA does not permit the development of the same shale (Tarsands) extraction methods in COLORADO?

  6. I do see the Tar Sands and the other environmental problems you noted as major issues. However, our cold weather seems to be part of a much larger scale pattern. Cold weather has stretched from Alberta to Newfoundland and in my opinion, is more in part to arctic blasts, than human caused climate change. Unseasonably large troughs and the notorious Hudson bay vortex are major contributors to this pattern.

    While Global Warming may have the reverse effect on Manitoba (as some climate models have shown), there is really no way to provide it. In order to show that as fact, it will take decades of new climate data to calculate a new trend.

    I may be way off base here, but that is what I think.

  7. I'm not sure if localized sulfur emissions would have the same effect as large scale volcanic ash emissions in terms of atmospheric cooling. I think localized sulfur emissions would be more of a factor for downstream environmental impacts such as air quality and acid rain issues than large scale cooling. But I'll admit I'm not an expert in this area..

  8. Rob as you and others have noted, the sulphur compounds and water vapor (acid Rain) produced by Volcanic eruptions have functioned to offset global warming in the past. They cool the earth immediately for as long as two years, downwind of the emissions. Recent research has concluded that the acid rain they produce also results in a slow down of wetland produced methane gas for up to 15 more years offsetting global warming. (more cooling)

    Manitoba's acid rain mega contributors are the two in province smelters and the Alberta Oil sands.

    A Mar 28/29 eruption sent a 50000 ft mostly sulpur and Ash plume into the stratosphere from Mt Redoubt near Anchorage Alaska.

  9. If we need a reason my money is on the Volcano.

  10. Theory has it the water droplets reflect sunlight insulating the earth below. Must have been standing under a cloud in Charleswood that day

  11. I forgot about the Redoubt eruption.. gotta wonder if that has had an effect this summer, especially given the prevalant NW flow aloft we've had this year..

  12. It would be interesting to look at the mean 500 hPa flow and anomalies for June-August 1992...

    I think it will be tough to reach 30 C on Sunday. As Rob mentioned, models show potential for elevated convective activity thru midday Sunday. Fairly well defined LLJ but limited moisture return... in fact the best moisture is trapped under the main upper low off to the NW. At the very least clouds will keep a lid on heating until later afternoon. Western Manitoba will be better entrenched under the low and mid level thermal ridge and stands a good chance of seeing low thirties.

    I do not see much threat for surface based convection on Sunday either. There will be decent cap present and lack of trigger mechanisms. I think cap will break over eastern Saskatchewan along the surface trough Sunday afternoon. Discrete supercells initially... I think best chance for tornadoes will be areas north of the trans-canada, where surface winds will be more backed (SSE) along a subtle warm front/trough.

    I would expect convection to get better organized into some sort of complex as LLJ cranks up ahead of midlevel low Sunday nite/ Monday morning. We could be set up for another 'thunder sandwich' day (Monday) depending on timing of surface trough and clearing of debris cloud.

  13. These are the same types of models they use to predict global temps will rise. Very reassuring

  14. This comment has been removed by the author.

  15. Guys, forget about waiting 15 more years to figure out what is causing this unseasonably coolish weather...

    The Atlantic Monthly, in their cover edition on "how to fix the planet" has an article about "geo-engineering"...

    Please read it.

  16. This month will almost for certain be the 8th month is a row of below normal temperatures!

    We would have to get some VERY VERY hot weather for us to end up above normal!

  17. Interesting Article James..Do you suppose that means to geo engineer a warm up of our winter and/or summer we could just as cheaply reverse the process and run vacuum hoses back through FGD scrubbers .

    Sounds like the race is on.

  18. NOTICE I am desperately seeking a forecast involving the words "excessive heating " "Heat wave " without the use of artifial warming techniques. Does anyone see anything in the future at all??

    Please POST to ROB'S BLOG soonest.

  19. No excessive heat I can see in the foreseeable future. Upper ridge keeps bouncing back over western Canada, giving BC and the Yukon a decent summer.. but that NW flow is killing us further east.

    I see the 30C high for Sunday was dropped to a more reasonable 27C for Winnipeg. Set up wasn't there for a 30 degree day over Winnipeg with a southerly valley wind kicking in out of a departing cool ridge. 30C more likely to our southwest on Sunday as Daniel noted, with 30C likely aong the western RRV, and 32-35C possible over the far southwest. Will only last a day though before another cold front pushes through..

  20. Tomorrow looks very intense near the MB/SK border. If the 500mb jet streak moves a bit farther east towards the MB/SK border tomorrow, watch out! The synopsis:

    850mb - 40kts SSW
    700mb - nil
    500mb - 30 to 50kts, possibly 60kts WSW
    250mb - 60kts W

    CAPE - 2000 to 2500J/kg
    LI - (-4 to -8)
    EHI (3km) - 0 to 3.0
    0-6km bulk - 40kts (avg)

    Main concern is cap. 10C temps at 700mb aren't great, but aren't insurmountable. Main shortwave/vort max is in central SK. With cold front combination, most favourable initiation area is in SE SK, moving into SW MB throughout evening. Area near Manitoba border is most favourable for supercells around 00Z.

    Other concern is the deep shear. 250mb jet streak stays in SK, with only 60kts in the severe risk area. 500mb jet streak has same problem. This may only yield 0-6km shear of 40kts, which is sufficient for supercells, but far from ideal.

    As I mentioned, if the main mid-high level jet streaks move into a more easterly position, we could see a much more serious situation. With tds between +15 and +19C, there could be an isolated tornado or two. This all depends on whether the cap breaks and when. Also whether the bulk shear is high enough.

    P.S. Equal instability and stronger shear around Flin Flon could yield interesting situation. Along with better cooling aloft, we may be talking northern Manitoba tomorrow!

  21. Western Manitoba does have the best chance of severe thunderstorms this evening.

    The forecast yesterday showed the upcoming week as warm and sunny for the most part..... NOW

    It looks cloudy and showers!
    with temperatures struggling to get to *normal*

  22. After spending six weeks in China, I'm enjoying this weather. We spent the last days in Shanghai and the weather was very hot and humid. When we arrived the train reported 39.6 °C and the humidity was very high. (Couldn't seem to find anyone who was interested in knowing current conditions. :) ) I literally spent the day soaked in sweat all the time we were out. So this is a treat, to go places in comfort again.

    Interesting too, I could access Rob's web site in China, but not this blog. I guess anything with "blog" is blocked.

  23. Situation around the MB/SK border looks interesting. Main concern is still cap.

    Moisture is good, generally tds range from 13 to 17C. Roblin is highest, at 20C. This is yielding CAPE values between 2000 and 3000J/kg. Odd SBCAPE number around 4000J/kg in places like Roblin.

    Wind shear is a potential problem, with bulk shear number only at 30 to 40kts. This isn't terrible, but I would like to see at least 40 to 50kts for an elevated supercell risk. Offsetting value is high EHI number, ranging from 3.0 to 7.0. EHI like this is more than sufficient for tornadoes.

    Main threats appear to be strong winds and possible tornadoes. Freezing level is very high (14K), which limits severe hail risk. However, with instability of 4000J/kg, severe hail is still very possible and remains a risk. Lower areas of instability will see a very low risk of severe hail.

    Looks like we could be waiting well into the evening for initiation. With temps only in the high twenties, rather than low thirties, it is possible that the cap won't be broken. It will be important to monitor the satellite to watch for first vertical development.

  24. Did everyone enjoy the "hot" weather today????

    Well hope you enjoyed it because it's back to below normal temperatures and cloud cover for the first half of the week!

    After that... the models are showing another 500 mb low in Northern Ontario circulating in the cool air for the rest of the week!!!

  25. This comment has been removed by the author.

  26. Line of towering cumulus west of Duck Mtn region in Saskatchewan...

    Convection will likely organize itself tonite as LLJ cranks up. Line may build south into the intensifying LLJ, perhaps as far down as Winnipeg. Best chance would be around the 2 - 4 am timeframe. Trough bows out and moves quickly thru us. Line segments with strong winds and heavy downpours will be the main threats. Models show surface trough hanging up from a near Fargo to Kenora line tomorrow. If it stalls further west, SE Manitoba may be in play tomorrow for severe storms. I wouldn't rule out a few wrap around cells trying to form in mid level dry slot.

  27. Some very intense storms are now firing in western Manitoba!

    Look at that storm to the west of Russell!!!!

  28. Has anyone seen a splitting supercell before on radar???

    Well look at that storm near Russell split into 2!!!! WOW

    One storm then races off to the northeast while the other storm is now hooking southeast!!!!

  29. Don't be surprised if you see a hook echo with one of these storms. EHI values are very high and these storms are obviously tapping the very high instability (3000 to 4000J/kg in many cases).

    Looks likely that we will see a line develop later on, possibly affecting more southern areas overnight (as Daniel mentioned). MLCAPE values become elevated as moisture pools ahead of the front. Along with a fairly strong LLJ, a marginal wind event is possible should things organize properly.

  30. Last couple of radar images show a possible hook echo on the Russell storm as it turns to the right, with some good mesocyclone signals on it. Golf ball hail out of it earlier..

  31. Alright everyone, attention!

    Take a look at the RADAR...this is what storms should look like. None of this marginal 'nickel sized hail' stuff. This is a full blown supercell, with possible hook echo (tornado).

    I guess severe weather season is now finally here!

  32. Taking a look to my west from West Winnipeg I can see the massive anvil cloud from this supercell that is still 200 km away!!!

  33. Im surprised there's no tornado Warnings out on that cell, given the hook echo and rotation on it.

  34. Scott!
    I took a picture, the best that I could get considering the darkening conditions, and my $80 dollar camera!

    I will email to you!
    I know you like photos on your website!!

  35. Almost a textbook supercell out there tonight! This storm is obviously taking advantage of the extreme EHI values in western Manitoba. I am almost expecting a tornado out of this one. At the very least there should be some huge hail and very strong winds.

    Some more storms firing behind the main supercell. Not sure how these ones will fair...hopefully they don't kill the big one.

  36. You can see the storms off to the west on the webcams on Rob's site.

  37. Very bad attenuation on the foxwarren radar earlier (GRLevel3 feed seems frozen). Also noticeable on the webcam are ominous looking altocumulus castellanus (indicating elevated instability). I have not seen them very often, and with the twilight sky it produces quite an effect. Question still remains how far south this convection will build overnite.

  38. Looks like a bowing line segment is forming off the Manitoba escarpment between Dauphin and Minnedosa...

  39. Line of storms quickly forming to the east of Portage La Prairie !

    I can see the lighting in Winnipeg already!!

  40. Severe thunderstorm watch issued for Red River Valley!
    Storms quickly getting stronger!!

  41. If that storm northeast of elm creek hold together Winnipeg will be getting one strong storm!!

    Hailstorm ???

  42. the winds are starting to pick up here in St. Vital.

    This could be the city's first real good nocturnal light show of the season.

  43. Some back building and training associated with these line segments:

    1) along the highway 23 corridor north of Morden

    2) Possibly along the south end of Winnipeg

    Intense cell that affected areas just west of perimeter weakened significantly...

  44. Fair thunderstorm underway in River Height. Nothing too wild yet. Sounds like moderate rainfall rate. Judging by radar and lightning detection we shouldn't get extreme weather.

  45. The south end of the city bearing the brunt of the storms and rain yet again...

    Very potent cell with torrential rain moving very slowly giving very high precip totals. Another strong cell affecting south Winnipeg.

  46. Sorry that potent cell is around La Salle

  47. I'm off to sleep... I am sure we will hear of 50 to 75 mm rain totals and hail from SE Winnipeg down thru Domain and La Salle areas.

  48. Tornado chances with yesterday's supercell(s) were quite low given the high temperature/dewpoint spreads. Moisture was very limited throughout the column. There was no deep moisture present...and any moisture that was around was near the surface. Since the return flow only started earlier yesterday...we can obviously conclude that the moisture never came from the Gulf of Mexico. Moisture was probably directly attributed to local Evapotranspiration. This being said EHI values were fairly high. That is not a real good indicator to tornado potential because EHI is just the combination between helicity and CAPE. Yes CAPE ties in heat and moisture...but it does not use the moisture throughout the entire column. This just shows that one has to look at the entire picture before assuming tornadogenesis. Tornadoes are very stubborn things. They require quite the witch's brew before they develop. I've chased several times this year from Texas to Montana to Kansas, etc and have only encountered rain-wrapped HP messes!

    A lot my of the chases ended in failure because the helicity axis outran the instability axis. Supercell's that did form quickly became outflow dominant and sent out an outflow/gust front that surged rapidly ahead of the storm. Yes the great turning with height was present...but if a storm outruns the can NOT essentially root into the boundary layer and tap into the deeper moisture which ultimately KILLS the tornado chances. I chased the Grand Forks supercell back on June 26th, and that was the best storm I've chased this year. The same problem existed with that storm, but the storm was able to catch up to its outflow and wrap up quite nicely. When it did...velocity couplet would blossom on radar and you could see the wall cloud drop from the base of the updraft. Once it did that it'd quickly surge out a gust front. I think more research has to be done into the Rear Flank Downdraft of the Storm. It must pulse and pulse as it moves along. A large pulse can cause the cool air to descent rapidly while a subtle pulse can help the storm stay rooted...who knows!

    Soundings for yesterday probably showed fatter cape near the surface with skinny capes aloft, since the moisture backed off significantly as you went up. So in conclusion..if moisture was DEEPER...then tornadoes would have likely developed. There were high freezing levels too so hearing about the GOLF BALL hail was quite surprising to me...but that sized hail was likely caused by the storms forming in HIGH CAPE environments with updraft speeds being able to sustain larger hail stones!

    If temperatures were in the 30's...and if dewpoints were in the low 20's...NOW that would have changed the situation big time!

    I need my cereal...i'm starved...then it's off to Edmonton!

    Cheers...oh yeah...quite the boomers last night...scared the $hi# out of me just after 2am! Not used to thunderstorms in Winnipeg this year! HA!

  49. Around 2:00 we had heavy rain, wind and hail in La Salle.

  50. I totally forgot to wrap up the temp/dewpoint part.

    Higher temp/dewpoint spreads will lead to higher cloud bases. Higher cloud bases aren't great for tornado development. A lower dewpoint spread keeps the updraft base closer to the ground...and when a wall cloud forms...then you are in business.

    Again you can you have a low dewpoint spread with high dewpoint near the surface, but dry air aloft. If this is the case then your storm is moisture starved and will not be a tornado-producing machine.

    4 ingredients for tornadoes



    SHEAR (aligned perfectly) - backed surface winds with approaching low are best for winding up that hodograph!

    SE - surface
    S - 925mb
    SW- 700mb
    W - 500mb
    WNW - 250mb
    Amazing shear profile!

    TRIGGER - warm front works magic...but these are rare for focusing severe weather over us..and with any warm front set-up comes the chance have having a major CAP bust! - so to be safe...I'd say surface trough with decent cooling coming in behind it!

    Despite all of that...tornadoes might not form! I swear it's something on the ground that initiates the development of a tornado!

    Click my name for video from the June 26th supercell over Grand Forks, ND.

    Now I'm done!

  51. Thanks Justin.. good info on the dynamics of tornadoes.. still an elusive beast to forecast. The flip side to tornadoes not forming when everything seems to be there, is when they DO form when you weren't expecting them. Mother Nature is always full of surprises..

    Best of luck in Edmonton!

  52. Only got 1 mm of rain from last night's storms.. heaviest cells passed to our south and east... thankfully! We don't need more rain here!

    Looks like 10-20 mm over southeast parts of the city, with 48 mm down at the Morris ag wx site.

  53. Justin Seems like adding the right fuel (Cereal?)..completes the picture .

  54. I've never seen one of these before! What a great job.
    Best place for your complete Internet marketing