Hot summer weather continues to elude much of central Canada including the eastern Prairies as a strong upper ridge of high pressure persists over western Canada producing a northwest flow of cooler air for us. The result has been consistently below normal temperatures this month over southern MB with hot weather confined to western Canada, including the Okanagan interior of BC where forest fires are currently raging. (see 30 day temperature graph for YWG)
Not much change is expected for the rest of the month with the upper ridge expected to persist over BC (see attached 500 mb GFS prog for Friday) maintaining warm temperatures out west with near to below temperatures over the eastern Prairies. Although the absence of hot humid weather is a disappointment for beach and cottage goers in southern MB, the weather has been comfortable for most residents with the benefit of little or no need of air conditioning. As of July 19th, the mean monthly temperature in Winnipeg was 15.8C, putting it on pace for one of the coolest July's on record in the city since records began in 1872. The top two coolest Julys in Winnipeg were 1884 (15.4C) and 1992 (15.9C) Both those years followed major volcanic eruptions the previous summer (Krakatoa in 1883, and Pinatubo in 1991)
Hot summer weather continues to elude much of central Canada including the eastern Prairies as a strong upper ridge of high pressure persists over western Canada producing a northwest flow of cooler air for us. The result has been consistently below normal temperatures this month over southern MB with hot weather confined to western Canada, including the Okanagan interior of BC where forest fires are currently raging. (see 30 day temperature graph for YWG)
Not much change is expected for the rest of the month with the upper ridge expected to persist over BC (see attached 500 mb GFS prog for Friday) maintaining warm temperatures out west with near to below temperatures over the eastern Prairies. Although the absence of hot humid weather is a disappointment for beach and cottage goers in southern MB, the weather has been comfortable for most residents with the benefit of little or no need of air conditioning. As of July 19th, the mean monthly temperature in Winnipeg was 15.8C, putting it on pace for one of the coolest July's on record in the city since records began in 1872. The top two coolest Julys in Winnipeg were 1884 (15.4C) and 1992 (15.9C) Both those years followed major volcanic eruptions the previous summer (Krakatoa in 1883, and Pinatubo in 1991)
Rob!
ReplyDeleteYou state that the two coldest July's on record were during and after volcanic eruptions!
Is there some volcanic eruption that I'm not aware of THIS year????
So if not.....then this cool month will be that more amazing!
Mount Redoubt eruption happened recently.
ReplyDeleteThat's right.. Mt Redoubt erupted in southern Alaska in March, although it wasn't on the scale of a Krakatoa or Pinatubo. Still, I wonder if the proximity and timing of the event has had some effect on our prolonged below normal pattern this summer.
ReplyDeleteThe USGS has an excellent site on Volcanic Gases and their effects to lower temperature. Link on my name
ReplyDeleteThe Redoubt Volcano during the last week of March Ash dispersion was south west... But the Mtn has been belching SO2 for weeks before and after and still is. As Daniel posted a few days ago it would be interesting to know the actual dispersion patterns for the first 4 months of 09
There is also a site which traces these dispersions.I'll try to find and post the link
If we are thinking 8 consecutive months of cold blame Mt Kilauea's 15 months of unprecedented lava flow and enormous gas release. See USGS site
ReplyDeletehttp://hvo.wr.usgs.gov/volcanowatch/2009/09_03_12.html
It's interesting to hear various theories about why the past 8-9 months have been below average temps. But if you remember last spring/summer (2008) it was not exactly warm. In fact, I'm hard pressed remembering a warm spring (in particular) and summer going back the past several years. I can't help but wonder if this isn't part of something bigger picture (certainly beyond my layman knowledge; just an observation)
ReplyDeleteThis is the EC Mt Redoubt dispersion forecast model (GEM) Mar 27. Interesting pattern particularly the 96 h
ReplyDeletehttp://eer.cmc.ec.gc.ca/people/Alain/eer/emergencies/Redoubt/Redoubt.html
Mean temperature this July is 17.6C in Steinbach. However, bear in mind that this is taken from a weather station comparable to the Forks. High temperatures are generally the same to slightly warmer than the Steinbach airport, with nighttime lows almost always warmer than the airport. This could put the mean at 1 to 2C warmer than the airport on average.
ReplyDeleteMark..
ReplyDeleteNo doubt there are several variables coming together to maintain a persistent weather pattern for such a long time. Volcanic eruptions may be just one of the contributing factors to one degree or another, depending on the extent and concentration of emissions.
Blecch.. not liking the look of the GFS for the end of the month over us. 546 thickness, +4C 850 temps.. We have a couple of near seasonal days between now and then, but overall, looks generally below normal for the next couple of weeks. Looks like we won't hit 30C this month.
ReplyDeleteSupercell chances for Winnipeg area tomorrow according to the NAM. Instability, Shear, Trigger, & moisture all present...but so is the cap.
ReplyDeleteWhat do you think?
I'm in Edmonton and am kind of upset that I'll be missing this possible chase day. My flight arrives back in YWG around 7:45pm...so I'll be arriving after the show starts. I think the cap will break...and if it does...then hmm!
Supercell chances tomorrow hinge on daytime heating. The models are showing a heavy cloud deck moving in around noon. Should this occur, it would severely hamper our convective chances. However, if we manage to get into the mid to high twenties (+26 to +30) like the models show, then supercell chances will be high. The models are showing slight tornado chances in SE MB, but I doubt anything will occur with relatively low CAPE values that are expected.
ReplyDeleteJudging by the cloud cover, I would be surprised if we hit the forecast high of 28C. Looks to be some light shower activity west of the city.
ReplyDeleteMark I agree with your comments about cooler weather since at least early summer last year
ReplyDeleteThe Aug 2008 Mt Kasatochi eruption in the Alaskan Aleutians I'm guessing has made some contribution..
Findings published for the Mt Kasatochi eruption .which produced the largest measurable SO2 Stratasphere dispersions of a northern hemisphere volcano since 1978 ?
http://adsabs.harvard.edu/abs/2008AGUFM.A51J..07C
Today's severe threat will depend on heating. Should we reach +26 or higher, CAPE values will be sufficient for severe storms and the cap should break. With tds generally between +16 and +18, moisture is good. Moisture depth is also decent, with 850mb tds around +12C. Shear is sufficient for supercells. Hopefully the instability will build.
ReplyDeleteMB is actually experiencing a massive drought - of forest fires. 570 dropping below the province for much of next week! The drought continues.
ReplyDeleteOf course it's due to a lack of solar activity ;)
No forest fires and no lightning.or at least a few less than the> 350/yr we average or >1000 yr visible from the city
ReplyDeleteAll due to solar activity :)
But low solar activity allows more galactic cosmic rays to reach Earth, supposedly providing a trigger for lightning (and increasing cloud cover). I'm actually surprised by how much lightning we've had (over the whole province it's been fairly normal) given the weather pattern.
ReplyDeleteSevere thunderstorm chances are looking good for this evening.
ReplyDeleteTemps have warmed into the mid twenties (+25, +26C), with tds between +17 and +19C. Moisture depth looks decemt as well, with 850mb tds generally +8 to +12C. This should yield CAPE of 1000 to 2000J/kg. If we warm into the high twenties, CAPE values reach 3000J/kg in localized pockets.
Shear remains very good. 60kt of effective shear over the RRV attm. Veering profile still present at YWG, this could create a tornado risk in SE MB should supercells develop.
Capping remains strong over S MB, but should give way ahead of the front along with slightly higher temperatures this evening.
32 C in Grand Forks as of 5:00 pm!
ReplyDeleteMeanwhile most of Southern Manitoba have been socked in the cloud cover and mid 20 C temperatures!
Typical for this summer!!
Is it just me...or does this storm cell currently look like it likely has a possible hook echo/rotation?
ReplyDeletehttp://i286.photobucket.com/albums/ll103/Winnipegweather/svrcell92309.jpg?t=1248395398
Cap seems to be suppressing convection over southern Manitoba. Storm near Portage was beginning to turn quite severe, but is now starting to become disorganized. Almost looks like it wants to split as of 8:50.
ReplyDeleteWith temperatures falling into the low twenties, cap will become very strong. Only chance is elevated convection, however MLCAPE is also becoming capped.
Impressive tds tonight. Generally around 20C, with some reaching above that. My highest dewpoint of the year was recorded today...21C or 70F.
According to RADAR, the storm just west of Winnipeg has potential for severe wind gusts.
ReplyDeleteglobal warming HA¡ maybe the precurser for the next ice age
ReplyDeleteJon As you were posting that I was walking north on Pembina...that Anvil was a H*** of an impressive sight
ReplyDeleteGoing to polo park I saw the cell that affected SW Winnipeg, so I went for a closer look lol. Fairly good structure on the storm with decent shelf cloud out front. I was surprised to see some airplanes flying just ahead of it while landing at YWG. I followed the northern fringe of the rain shield and was rewarded with a view of a wall cloud from Marg Edie Park and sportsplex (sp?... doesn't appear on city maps). Wow there are so many deer in Charleswood!
ReplyDeleteBtw... MLCPAE is not a good indicator of elevated instability. It is simply used when surface moisture is very shallow to get a more realistic estimate of dewpoints at the base of updrafts. It is obtained only by mixing the lowest layers of the atmosphere. MUCPAE (MostUnstableCAPE)is a much better estimate which calculates the maximum buoyancy of parcels lifted from various pressure levels. It seems to not be available for the general public however.
ReplyDeleteHas anyone revised todays forecast ?
ReplyDeleteSouth Wpg temps already exceeds the highs for today
Did anyone get any storm damage from last nights storms?????
ReplyDeleteI live in South Winnipeg (Island Lakes) and there barely a sprinkle. Lots of lightening around us, but next to no rain.
ReplyDeleteEC is saying the current conditions are 'distant precipitation' - that's a new one!
ReplyDeleteHad a report of nickel size hail from the South perimeter last evening. Brady Rd landfill reported 12 mm of rain with the storm as it tracked south of the city..
ReplyDeleteAnyone wanting hot weather should go to BC this coming week. Check out the special weather statement: http://www.weatheroffice.gc.ca/warnings/SWS_bulletins_e.html?prov=bc
ReplyDeleteThanks for the link Anonymous!!!
ReplyDeleteLook like interior BC is going to get an epic heatwave!!!
They can send some that heat over here if they want!!!
Even Baffin Island is having a heat wave of its own.. a record 25C in Iqaluit yesterday, with 25C likely today and tomorrow as well. Keep in mind their normals are 12C, and they've reached 25C less than 5 times in the past 60 years. Record highs also set at Pond Inlet, Clyde and Cape Dorset.
ReplyDeleteSo if you want summer this year, head way north or way west.
We have also had 8 consecutive months of below normal temperatures here in Saskatoon. The average high temperature in 2009 for July was only 22.5C... A full 3 degrees below normal.
ReplyDeleteArctic airmasses have dominated... A warm southerly flow will form once every couple of weeks but this intrusion of milder air is short lived... A few days at most. There has been a real lack of humid heat...
Also the cooler temperatures, northerly flow and low R.H. has led to an almost thunderstormless summer here... I have only recorded 4 days with thunderstorm activity since May of this year.
Some of the overnight lows are alarming... 4 nights of below freezing temperatures recorded in June, 5 overnight lows in July under 5C... With 2 of those nights coming close to frost.
Yes, I cannot see the current pattern weakening... Omega block in it's glory.
I suppose it will be like last year... Cold, wet summer only to warm in September when all the pools, parks and recreational facilities have closed for the year.
Living on the Prairies is for the crazed... Small wonder populations of Saskatchewan, Manitoba and the Dakotas have not grown much in the past 75 years.
I've never seen one of these before! What a great job.
ReplyDelete___________________
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