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| Projected rainfall totals (inches) Mon-Wed. Heaviest rainfall expected over SW MB with 75 mm possible |
Sunday, May 29, 2016
A brief dry period.. then another round of showers and thunderstorms on the way Monday night into Wednesday. Areas of heavy rainfall likely especially over southwest Manitoba
It's been a wet week over much of southern Manitoba this past week. Since last Sunday (May 22) general rainfall amounts of 40-70 mm have fallen across much of southern Manitoba, with locally heavier amounts in some places. (I've recorded 70 mm at my site in SW Winnipeg since last Sunday night) Today saw a welcome break from the unsettled weather with partly sunny skies this afternoon, and we'll enjoy rainfree weather much of Monday before another bout of wet weather moves into southern Manitoba. The culprit this time will be a developing low pressure system over North Dakota which will spread showers and thunderstorms over southwest Manitoba later Monday into Monday night, moving into the Red River valley Monday night into Tuesday. The heaviest rain is expected Monday night into Tuesday morning.
Rainfall from this system will be highly variable since localized areas will see heavier amounts from slow moving or persistent heavier shower or thunderstorm cells. Places which miss the heaviest convection will see lower amounts. In general, most places in southern Manitoba will likely see 20-30 mm of rain Monday night into Wednesday morning, with heavier totals of 50-75 mm possible in some areas.. especially over the southwest corner of the province (Melita, Virden, etc) where current guidance is indicating the greatest probability of heaviest rainfall. At this point, one should focus on the potential for heavy rain over the next few days instead of the exact location.. which will likely change slightly as models try to predict the track and intensity of this system.
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Yeah, models depict showers/t-showers organizing into large band that will rotate through the Winnipeg area tomorrow morning. Low becomes vertically stacked and LLJ wraps into the disturbance.. fueling embedded convection within that band. Thereafter, models suggest dry slot will move north in the afternoon. Will have to watch for any clearing and destabilization which could lead to more shower formation. Overall, most models still showing totals of 15-30 mm through Wednesday.
ReplyDeleteMost guidance shows bulk of rain moving through Winnipeg between 5 am and noon with a good shot of 10-20 mm within that period, helped by embedded convection and perhaps even an overnight elevated thunderstorm with some good downpours. As mentioned above, precip tapers off in the afternoon as we get dry slotted while SW MB/SE SK/wrn ND deal with wrap around rain in the comma head/def zone of system leading to the heavier rain totals out that way. (heavy precip guidance has been consistent in suggesting upward of 75 mm in that area)
DeleteScattered showers possible in the dry slot with more frequent showers/periods of rain Tuesday night into Wednesday as low drifts over RRV and then east into NW Ontario. Another 5-10 mm possible through that period for overall totals of 15-30 mm for Winnipeg/RRV over next 48 hrs.
WPC QPF guidance was excellent showing an 80 mm maximum bullseye over the triple border intersection of MB/SK/ND. Pierson MB (far SW MB near the SK/ND border) has picked up 68 mm since last evening, and there has been reports of 60-80 mm over SE SK in the Maryfield-Fairlight areas. 10-20 mm further east in the RRV from this morning's transitory convective band. Overall, guidance was very good in this case highlighting 2-3+" rainfall over far SW MB.
ReplyDeleteRob, is there any reprieve from all this rain, on the way or are we in a active pattern for sometime to come?
ReplyDeleteOnce this system moves out later tomorrow, we get a dry day Thursday, but then another system will threaten more rain Friday, although this should be a band of showers ansd possible thunderstorms rather than an all day thing. After that, we should gradually dry out over the weekend into next week with warmer temps, along with a slight chance of showers again by next Wednesday. After that.. there are some signs that we may get some ridging over us by mid June which would keep us in a less active and warmer pattern, but we'll have to see if that happens.
DeleteOn average, June is our wettest month in southern MB thanks to increasing surface moisture from maturing crops which can help fuel heavier showers and thunderstorms. Hopefully these last 2 weeks make up for less precip in June.
I ended up with 18 mm today, while the airport had 16 mm and the Forks had 19 mm. General amounts in the city ranged from 15-25 mm. Less rain south of the city with only 10-13 mm from St Adolphe to Emerson and over SE MB. 20-35 mm just north of the city into the southern Interlake and Pinawa area. 10-20 mm over western RRV with 30-50 mm west of Lake Manitoba (Alonsa, Gladstone) The big winner (?) this round was the southwest corner of Manitoba which saw 50-70 mm in the Melita/Pierson/Reston areas.
ReplyDeleteWhat a change of fortune these past 10 days. For the first 3 weeks of May, I only recorded 13 mm of rain and things were looking quite dry. With today's rainfall, I've recorded 88 mm in the past 9 days, for a monthly total of 101 mm. Average precip for the month of May in Winnipeg is about 57 mm, so we easily surpassed that average in the past 9 day alone!
Rob a liitle beyond your usual territory but how have the.northern forests of alberta , Saskatchewan and The manitoba/northern Ontario forests done for rain in the last two weeks?
ReplyDeleteNot sure about the last couple of weeks, but overall since April, precip has been generally below normal from northeast Alberta through northern SK into nrn MB, except near normal along the MB/SK border.
DeleteNice to see the sun again today.. sure can use it to dry up some of that water of the past 2 days. But one day won't cut it.. we need a good week or so to dry out nicely. Unfortunately, more wet weather on the way Friday with a band of showers coming through in the morning, then scattered thunderstorms likely in the afternoon as a wedge of more unstable and humid air moves over the RRV (dewpoints of 15C or more!) Won't be a complete washout, but general amounts of 5-15 mm likely over much of southern MB Friday, with isolated amounts of 15-25 mm under heavier thunderstorms possible.
ReplyDeleteRob, the NAM has now backed off on thunderstorms occurring in Southern Manitoba tomorrow. What are your thoughts on this? It seems we can never get good storms in Manitoba.
ReplyDeleteModels seem to be focusing stronger convection with main wave moving through eastern ND and northern Minnesota. That could be robbing energy from tstorms over southern MB, although some may still be possible in the afternoon if we get some sunny breaks. Otherwise, we'll likely just be contending with a band of showers pushing through RRV/southern MB Friday, with general mounts of 5-10 mm. Hopefully we don't get any heavier downpours.. we don't need any more rain for awhile!
DeleteYeah, models suggest most convection and precipitation to be concentrated around two features: intersection of the LLJ and surface warm front (which will stay well to our south); and an inverted trough extending north from the slow-moving low (which will stay just to our west).
DeleteMain instability and elevated convection sets up in a band from Fargo to Fort Francis; while more general rain and showers from western RRV and SW Manitoba. Models actually show little QPF for areas east of Winnipeg like the Whiteshell and SE Manitoba.. cloudy conditions, but with limited forcing.
I still think though that we have a chance at storms here tomorrow given some of the other models such as the GEPS and GDPS. They are also forecasting storms just south of us. Good chance at seeing some pop up storms, I also put us in a marginal risk of severe storms tomorrow in pretty much all of the southern part of the province. I run Manitoba weather centre along with a friend of mine. We'll see what happens, but I think that the NAM is underdoing instability tomorrow afternoon and evening given a trough will work through the area.
ReplyDelete*GEPS and GDPS have shown instability levels from 700 to 2,000 Jkg in Winnipeg tomorrow.
ReplyDeleteRob, there are lots of rumblings that significant severe weather will be possible later this week here in Winnipeg and Southern Manitoba along with hot and and humid conditions.
ReplyDeleteWhat are your thoughts on this?
Yes, it does look like things will be heating up later this week along with increasing humidity, with the best chance of potential severe tstorms in the Thu-Fri timeframe. However, still a lot of uncertainty in timing of frontal passages (warm and cold) to be more specific at this point. But given the ingredients (temps approaching 30C, dewpoints in the mid-upper teens, frontal forcing, etc), the potential for severe tstorms somewhere across southern MB is certainly there.
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