Unfortunately, I don’t have time today to do a full write-up on what’s going on. This link is to a comment I made on another weather website. It’s rather technical, so I don’t feel it’s a good fit for my blog, but if you’re interested in seeing something a little more complicated than what I tend to post, check it out! 🙂
Tag: Rain
Summer is Pushing Into Southern Manitoba
The beautiful conditions we’ve had over the past while will take a slight break today, with notably summer-like weather pushing over the Red River Valley. With the Red River and Assiniboine River rapidly rising, how much rain will we see?
A low pressure system currently in Eastern Montana continues to push warm air northwards through the Dakotas towards Southern Manitoba. This warm air brought thunderstorms to Eastern Montana and the Dakotas overnight, and as they have pushed northwards, they have lifted up over the warm front and transitioned to elevated convection that, while weakened, is producing an area of rain that is pushing into our area.
As this precipitation continues to move northwards, away from the warm front, it will weaken as it looses it’s precipitation generating support. The rain that currently resides over the international border will slowly push north, and could give a few light showers to Winnipeg late this morning before it peters out. The main weather that will impact us is currently developing over southeastern Saskatchewan and Southwest Manitoba.
This area of rain visible on the southern edge of the RADAR image will continue to blossom as the low strengthens and overall lift in the area intensifies. This will then begin to track east-northeast later today and spread an area of rain across Southern Manitoba, including the RRV. The models are having some difficulties determining how much precipitation this will produce, which is to be expected, however their tracks for the precipitation are beginning to agree.
GEMLAM
GEM-GLB
GFS
NAM
These models are all from their respectice 06Z runs, except the GEM-GLB which is the 00Z run, showing the precipitation accumulation from 00Z – 06Z tonight. The NAM is a big lighter on the precipitation, but other than that, they all agree (more or less) on location and intensity of the rain. So what will happen?
The precipitation accumulation will vary significantly depending on the amount of embedded convection that manages to develop. Current indications are that after a few showers late this morning, rain will begin to push across the Red River Valley late this afternoon or early this evening. The rain should end over the Southern RRV overnight as the low pulls further north and shifts the precipitation north as well. In Winnipeg, the rain should end sometime early tomororw morning; likely before 8 AM. Total rainfall amounts are difficult to pin down, as it will be directly proportional to the amount of convection that develops, but I would put my money on a general area of 5-10 mm (1/5 – 2/5”). If any significant convection should develop, some areas could potentially see up to 15mm of rain (~ 1/2”).
Once this precipitation clears out, the rest of the weekend will remain a little unsettled. The warm front maintains its position across ND, which will result in the chance of rain over the RRV as convection rides up over the warm front into Southern MB. Next week looks quite nice, however, with mostly sunny skies and temperatures in the low-to-mid teens. How all this precipitation will affect the river levels remains to be seen, however any accumulating precipitation has people concerned with the extremely high river levels that already are impacting the RRV. For more flood information, Rob over at Rob’s Blog has put together a nice collection of flood links.
Rainy Day on Tap for Winnipeg
Winnipeg will see a few showers this morning develop into a rainy afternoon before it all turns to wet snow this evening as the first “summer-y” system of the year pushes through Southern Manitoba.
Hand-analysis of the 925mb Height/Thermal Field for 12Z March 20
A very summer-y low is passing through North Dakota this morning, with a warm front draped west-to-east across much of the state, just south of the international border, before it dives south through Iowa. This system has brought with it copious amounts of warm air and is the first real summer-like system of the year.
East of the warm front, in Iowa, a complex of thunderstorms are moving across the state, supported by a 60 kt 850mb jet riding over the surface warm front, bringing with it moist air with Θw values near 20°C. This 60 kt LLJ then arcs north and pushes into Northwestern Ontario. As can be seen by the red shading in the analysis I have done this morning, warmer air is being pushed up through much of Southern Manitoba, including the RRV, Interlake and Parkland regions of west-central Manitoba. With the surface warm front just south of the border and plenty of warm air overrunning it, this has brought a mix of precipitation for areas in Southwestern Manitoba across the Trans-Canada highway into the Whiteshell and north.
1.5km CAPPI Radar Reflectivities
Pilot Mound, Morden, Steinbach and Sprague should escape most of the precipitation until later today. Being so close to the warm front, the precipitation is actually developing north of them where the air aloft that is being lifted is saturating. For those areas, expect a cloudy day with drizzle likely and if the wind manages to calm a bit (say to 15 km/h or less) fog patches are certainly possible. By later this afternoon, rain should move into the area, though with accumulations of about 5mm. For Portage la Prairie, Winnipeg, Dugald, Selkirk/Gimli and the Whiteshell, showers seen this morning will continue to develop and intensify to an area of rain by this afternoon. Expect to see about 5-10mm of rain before switching over to wet snow this evening. Do not be surprised to see a few snowflakes today, though; as it is quite likely for there to be embedded convection in the rain bands, areas of heavier precipitation may be able to produce rain mixed with snow as the shallow warm pool is unable to completely melt all the precipitation.
12Z 20 March 2011 GEM-REG 12h QPF Accumulation valid 00Z March 21 2011
Further west, over the higher terrain, the precipitation will predominantly be snow. Dauphin/St. Rose/Minnedosa are under a heavy snowfall warning as 10-15cm of snow are expected by this evening. Fortunately, as this weather system is driven primarily by warm air, the precipitation should end quite quickly as the low pulls out of our area this evening.
All in all, it’s quite a good day to stay inside with a hot drink and read a book. A little bit of everything will be seen through the afternoon, and unless you’re a big fan of having a new “Rally Inspired” paint job on your car, it’s best to stay off the messy, messy roads.
The next significant weather system will pass through on Tuesday, and this system will receive plenty of attention as it develops as it has the potential to produce significant amounts of snow/rain, and could add uncomfortable amounts of water into the Assiniboine/Red River drainage basins. I’ll post some more information about that system on Monday when things are a little clearer.
Snow on the Way For Winnipeg
Our stretch of beautiful early-November weather will come to an end this week as a low pressure system moves across Southern Manitoba bringing rain and snow and leaving behind more seasonal weather.
A sharp upper trough sitting over the Pacific coast has helped set up a southerly flow throughout most of the Eastern Prairies over the past few days, bringing with it unseasonably warm and dry weather to Winnipeg and the Red River Valley.
Over the past day, however, the trough has moved eastwards and is now situated over the Rocky Mountains. Warm, moist air has been surging northwards out of the trough for the past day or two, bringing plenty of precipitation to Saskatchewan. Currently, a surface low exists in Nebraska, with an inverted trough extending all the way up to the Swan River region. A cold front is sitting in this trough, with a warm front extending across the northern regions of the Manitoba Lakes. In this visible image, the fronts are shown by the cloud/clear sky boundary over Manitoba.
Visible Satellite Image of Southern Prairies/Northern Plains for Tuesday Morning
This system has brought snow to western Saskatchewan, with some areas receiving more than 10cm of snow. The weather station at the Swift Current Airport reported 13cm of snow by 10AM today and a report of 10cm of snow was received from Stewart Valley, located just north of Swift Current. Further north and east of the Swift Current/Cypress Hills regions, most of the precipitation has thus far fallen as rain, however will switch over to snow by this evening. A few pockets of freezing rain have also shown up over east-central regions, close to the fronts.
This whole system will slowly progress eastwards today and tonight, but most of it’s movement will be northwards through the next 36 hours. By tomorrow evening, rain and snow will have moved into Southwestern Manitoba.
Precipitation Accumulations from the GEM-REG for Wednesday Night; 5-10mm of Rain is expected for the RRV before switching over to Snow on Thursday morning.
On Wednesday night, cold air is injected into this system and it begins to intensify and move off. By Thursday morning, rain will have moved into the RRV, and should switch over to snow relatively early in the morning as the winds back around the the northwest. There may be a slight chance of a brief period of freezing rain as the changeover from rain to snow happens, however I would expect it to be rather unlikely.
Precipitation Accumulation from the GEM-GLB for Thursday.
The possibility exists for 2-5cm of snow in areas close to the International Border and 5-10cm for areas a bit further north, including Winnipeg, on Thursday. Environment Canada will likely issue some sort of notice on Wednesday as a heads up to the first significant snowfall of the season for the RRV.
This system will move out Thursday night at a much quicker pace than it moved into our area. Skies will clear by Friday and we will be left with daytime highs in the -1 to -3 range with light winds.
So get out and enjoy the weather today. Mostly sunny skies should persist through most of the day and the expected daytime high should be around 14 degrees with relatively light winds. Winnipeg has a shot at breaking the record high today; the current daytime high is 14.4 degrees, set in 1923. Unofficially, Island Lake and Pinawa have both already broken their record highs for today.
So enjoy the warm weather, just don’t forget where you stored your heavier coats!
