Friday, September 25, 2009
Strong winds to bring cool change for Sunday.. gales, high waves for MB lakes Sunday night
The extended summerlike pattern of September 2009 will come to an abrupt end Sunday as a storm system tracks across Manitoba and intensifies over northwest Ontario Sunday night. Strong northwest winds on the backside of this system will draw in much cooler air over southern MB Sunday into Sunday night, with gusts of 70 to 80 km/h likely by Sunday evening over much of southern MB, with 90-100 km/h gusts possible on the eastern shores of Lakes Winnipeg and Manitoba. These strong winds will combine with high lake levels to create large waves.. possibly 3-4 metres high, which may cause problems along the exposed eastern shorelines of the lakes. In addition, the strong winds may result in tree limb damage and local power outages since most trees are still full of leaves thanks to a warm frost-free September. A similar storm system on June 27th brought 100 km/h gusts over southern Lake Winnipeg and resulted in extensive power outages through cottage country into the Whiteshell due to fallen tree limbs and power lines.
Posted by rob at 9:32 AM
Subscribe to: Post Comments (Atom)
Latest NAM has backed off on the 50 knots over the MB lakes Sunday evening/night.. showing "only" 40 knots now, with the stronger core of 50 kt winds passing by to our south in ND as well as developing east of us in NW Ontario Monday. This would result in 70-80 km/h gusts over the lakes, but not as bad as the June 27th event. This would still give some significant waves, 2-3 metres, but not enough to do serious damage. Inland, we'll probably get 50-70 km/h gusts, if the latest NAM is right. We'll see what future runs show, and of course, what the actual analysis turns up.ReplyDelete
The GFS is showing a very wet pattern for Manitoba to start October. A Colorado Low is forecast to form towards the middle of next week and then plague our region for several days. After that system moves through, the models show another series of disturbances bringing a moist pattern to our region. While the models have backed off on the idea of snowfall, they now are suggesting an extended period of unsettled weather, characterized by cold rains.ReplyDelete
Fog on RED River (Bishop Grandin) Just rolled in last 15 minsReplyDelete
That Lake MB n Wpg gale updates valued especially Eastern Shore info.
Latest guidance now indicates marginal gale event for the lakes. Sustained northwest winds of 25-30 knots likely with gusts to gales on the eastern shores (35-40 kt) with local gusts to 45 knots possible. This will still generate some good wave action but should reduce overall damage potential. Will keep monitoring..
At the end of next week there may not be any leaves left on the trees with all the windy conditions that are expected this upcoming week!ReplyDelete
Nice picture you have there!
I did not know Winnipeg had any palm trees!
The way this September was going, I thought I was back in Italy!ReplyDelete
Current conditions in Edmonton say "Light Snow" yet its 10C...is this possible?ReplyDelete
No.. snow is not likely when the air temperature is +10C. More likely, it's a result of a known problem with automated weather station observations in windy weather, along with poor coding. In strong winds, automated stations frequently record false precipitation readings due to what is known as "wind pumping". This is where strong winds trick the automated station into thinking that precipitation has fallen into the recording pan, when it's actually just vibrations or fluctuations in the pan from the wind. If the dewpoint is below freezing, the algorithm will code this false precip as "light snow" if the air temperature is below 15C, a rather high threshold that is used for aviation purposes since it could be snowing aloft with surface temps below 15C. So, the automated station "thinks" it's precipitating when it's not, and it "thinks" it's snow when it's not. This happens frequently at automated sites like Pincher Creek and Yorkton.ReplyDelete
Of course, a more sophisticated algorithm would see that a) it's windy, b) the air temperature is well above zero, and c) the airmass is dry. Hence.. the precip reading should be ignored, or at least flagged as suspicious. I understand they're working on installing new types of precip guages at the automated sites that do not have this wind pumping problem.. but it's a work in progress.
Whoa.. was that thunder I just heard in Charleswood?ReplyDelete
Yup, you bet it was Rob!ReplyDelete
I was pretty sure that was lightning in the last minute or so of the Bombers game too! (What a dramatic game finish, at that!)
Lightning was also sighted here in St. Vital with a bit of thunder.
Do you expect some lake-effect shower and storms later today?????
Some lake effect streamers developing off Lake Winnipegosis and northern Lake Winnipeg as the cooler air moves in. These should also develop off the southern lakes this afternoon into this evening as the colder air aloft deepens over the warm lake waters.ReplyDelete
It is really quite chilly today with a light jacket needed with those cool winds!ReplyDelete
Well tomorrow night looks like a hard freeze with temperatures forecast to hit the -1 C!
A hard freeze is not -1 C. The Americans usually qualify it as several hours below -2 C (28 F).ReplyDelete
There is actually still uncertainty as to how much clearing will occur tomorrow nite. Given that the lakes are still very warm.. it may tough for the ridge to scour out all the low level moisture. This is especially true since the high pressure centre will remain far to the north. If low clouds hang around a good part of the night, most areas will escape even a lite freeze (except maybe the airport station with its drainage effect).
Off lake streamers trying to get organized off the southern lakes this evening, with a nice band off Lake Manitoba just clipping southwest Winnipeg this evening. Low level steering winds of 320-330 degrees this evening will veer to 360-010 overnight which will shift bands west towards Portage before weakening by morning. Likewise, activity off Lake Winnipeg will likely shift towards Beausejour overnight.ReplyDelete
Wow! What a shock to the system. We've been spoiled for so long it's hard to adjust. It looks like we're in for some below normal temperatures in the next few day. Is there any possibility we could lose our high temperature record event for September?ReplyDelete
I would assume we are still on target for a record warm September. Am I right in thinking this way, Rob?ReplyDelete
As of the 27th, the monthly average temperature at YWG airport was 18.8C.. a full 2C warmer than the warmest September of 1948 at 16.8C. Inputting the expected temperatures for the next 3 days gives us a final average around 17.6C.. which would still make this September the warmest on record by a comfortable margin.ReplyDelete