Saturday, April 24, 2010

Dry spell continues.. wet weather by the end of next week?

The dry spell continues over Winnipeg and the Red River valley with no measurable precipitation recorded since April 2-3rd, a full 3 weeks ago. And the prospects for significant rain look slim for the next few days over most of southern MB as weather systems continue to bypass our area. There is a chance of some showers over southwest Manitoba Sunday afternoon into Sunday evening , but amounts are expected to be light. Dry weather is expected for the bulk of the upcoming week, but models are indicating the potential of our first significant rainfall over much of southern MB by Friday into next weekend as a large storm system moves into the Northern plains. Widespread showers and scattered thunderstorms are likely with this system, with areas of heavy rain possible over portions of the southern Prairies. It's still too early to say how much rain if any we'll be getting out of this system depending on its evolution and eventual track. However with things so dry over southern MB, the prospects of some beneficial rain is welcome at this point. Stay tuned..

27 comments:

  1. I was puzzled by the forecast change for Friday (Day 7) for Winnipeg changing from "cloudy with a 60% chance of showers" this morning to straight "sunny" this afternoon. Very odd considering Day 6 and 7 forecasts are based on an ensemble product which shouldn't change so drastically this far out. Even the ensemble guidance is showing precipitation over Winnipeg by Friday, so I remain puzzled by the forecast change this afternoon. At this point, I'd put more faith in the "60% chance of showers" forecast than "Sunny" for Friday.

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  2. Rob!

    Take a look at the latest ECMWF run and it looks like a land falling hurricane over Southern Manitoba!

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  3. Rob!

    I also forgot to mention that there is this new series starting on MONDAY the history channel called STORM PLANETS!

    It is supposed to be about weather on other planets and if that weather were to happen on earth what the effects would be!

    Just thought I would mention it!

    Cheers!

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  4. Yeah, this thing looks like it could be a big rain producer across much of the southern Prairies.. possibly mixed with wet snow over southern AB. Most places will welcome the moisture I'm sure! FWIW.. GFS is showing 60 mm of rain for Winnipeg from Thursday into Saturday with thunderstorms possible Thursday into Friday. Looks like a fairly complex system which models will likely be going back and forth with before we see some consensus.. if at all.

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  5. Has anyone heard the term "SDS"???

    (supercell deprivation syndrome)

    I think that is what I have.......
    Might have to call in sick tomorrow~

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  6. Good news maybe Dan P

    Although April Temps continue to resemble 1980, Pcpn and to a lesser degree temps are closer to 1969. April that year had only a trace of rain/snow on a few days.

    Precip Jan 1 to April 24 this year is 70.0mm (65.0mm 1969) Dan GF NWS Guru called it last December.

    Total Nov 1 to Apr 24th is 87.5mm ( 78.7mm for 68-69) and ROB has suggested we deduct 9mms for this months shield effect

    The last and most interesting comparison in this may be that as the EL NINO effect waned in 1969, Winipeg had 102mms of rain including 25.4 between April 24th and the end of April

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  7. Typos!! The last line Should read between April 24th and the end of May

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  8. Once again, southern MB enjoying the finest weather in the country as our incredible April continues. Cold with snow in AB and SK, rain in southern Ontario, and cool unsettled weather on the coasts. 19C here in the sunshine as of early afternoon, a wee bit warmer than the 9C that was forecast a few days ago!

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  9. Amazing the contrast in temps in a 5-6 hour drive. +2 in Regina and +19 in Winnipeg.

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  10. Winterpeg is an old saying, that seems to be becoming less true =D. Time to find a new nickname..

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  11. Actually, Winnipeg is just more continental than SK and especially AB. In a normal summer, there is a clear increasing gradient in avg temps in a line from Edmonton to Winnipeg. In winter,it's reversed. So 'Winterpeg' is still appropriate but only in winter.

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  12. This is the first time I've seen the precipitation off the SouthWest end of Lake Manitoba effect Quapelle and Regina.

    Is that where the +2 is coming from??.

    Link on my name

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  13. Jim.. I don't thank that precipitation is coming off Lake Manitoba. There's an upper low over the Regina area, and precipitation associated with this upper feature is wrapping cyclonically (counterclockwise) around this low. That explains why the pcpn over SW MB is moving to the northwest into southern SK.. quite unusual.

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  14. Rob!

    The latest GFS run is slamming southern Manitoba with a whole lot of heavy rain and very strong winds.

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  15. GFS is the wettest and most intense on the system that will affect us later this week, while the European model is the weakest and driest over us, and the Canadian GLB is a good compromise between the two.

    Personally, I think the GFS has overdone things with an unusually deep 973 mb low over the Dakotas by 12z Friday. The ECMWF is weaker (992 mb) and further northwest on the low putting more of the pcpn over southern SK, while the GLB has a 984 mb low over western ND, with showers and possible tstms moving into Southern MB Thursday and Thursday night, then dry slotting us on Friday as the bulk of the rain moves over southern SK. To me, this seems the most plausible of the three given the expected upper pattern, but it's just my own gut feeling. Suffice to say, it's a wait and see thing at this point. Time will tell if the models trend towards a common solution.

    In these cases, I like to go with the ensemble, which gives Winnipeg a 50% chance of at least 10 mm of rain Thursday into Friday, and a 25% chance of 30 mm or more.

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  16. Can anyone tell me if we even had 1 day that was below normal this month???

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  17. 12Z GEM has really strayed from previous runs...it is now showing 40 to 50mm in south-central Manitoba. On the other hand, the GFS is now more reasonable, showing 15 to 20mm for Winnipeg and points near the city. It is almost as if the models swapped opinions.

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  18. 30% of showers or FLURRIES on Saturday with a HIGH of 14 C

    Ok........

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  19. Daniel! The weather network says showers and FLURRIES with a high of 18!, for April 5th. What's going on?? =Þ

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  20. It was snowing in Regina and Saskatoon this morning!

    So the snow and cold air is not all that far away!

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  21. For the prediction of TWN that Jewels mentioned of MAY 5th,does anyone know how there could be a high of 18C but still have some flurry activity? This puzzles me.

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  22. A forecast that indicates flurries with highs of 14 or 18C is a result of sloppy or oversimplified computer programming. Flurries are not likely with temperatures like that, so the model is either seeing the flurries at night, and/or is overforecasting the high temperatures.

    It does appear however that we will be getting into a cooler pattern behind this late week storm system for the first part of May, with yes, the possibility of some snowflurries over the first few days. Based on that, temperatures will likely be below the normal high of 16C for early May.

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  23. Models continue to have varying opinions on how the upcoming system this week will evolve over southern MB. As Scott mentioned, Canadian model has trended towards the earlier GFS solution with a deep low now (975 mb) over central ND by Friday. GFS meanwhile has a 977 mb low over the Brandon area, putting most of the heaviest rain over SW MB and southern SK with some dry slotting over RRV/SE MB. ECMWF is weakest and most progressive on the low carrying the main storm over Minnesota into NW Ontario. again, Canadian seems to be the best compromise and closer to the ensemble solution.. but we'll have to see how the models trend over the next day or two. Still lots of uncertainty with respect to how much rain we'll get between Thursday and Saturday.

    Bottom line.. looks like a prolonged period of unsettled weather coming up beginning Thursday and continuing into the weekend. General estimate of rainfall over Winnipeg/southern MB through that period is 20-30 mm according to the ensemble, but some places will get more and some less depending on how this low tracks (as well as if there are any thunderstorms Thu-Fri)

    Note Saturday's high of +3C for Winnipeg with rain.. with no mention of possible snow, yet yesterday the forecast called for a chance of flurries for Saturday with a high of 14! Ahh, computer programming at its best. I would say that there is a possibility of wet snow by Saturday over southern MB on the backside of this system as colder air gets swept in, with unsettled and cooler weather continuing into Sunday and Monday. So the sunny forecast those days looks overly optimistic as does the highs of 14-18c. Looks like some payback finally for our glorious April!

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  24. Will be interesting to see how the higher resolution models handle this upcoming system as we get closer to the event. The first wave of energy will move into the western Prairies tonight into Wednesday with a surface low developing over southern AB/SK bringing rain or wet snow over those areas. The key for us is what will happen with the second wave of energy rounding the upper trof over the western US Thursday night into Friday that intensifies a low in the central Plains. This will be a key factor in determining the eventual position and intensity of this surface low as it moves into the northern plains and its associated precipitation shield over the southern Prairies.

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  25. Well, when the models are all over the place, I like to consult my loyal bloggers to tell us what they think will happen! So I've added a new blog poll... tell us how much precipitation you think will fall in Winnipeg between midnight Thursday and midnight Saturday. I've found that the general consensus on these polls is usually pretty good in coming up with a reasonably accurate answer... so cast your vote and be part of the blog ensemble!

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  26. Wow.. this thing looks like it will be a heavy snow producer for the southern foothills of Alberta tomorrow night into Thursday. GEM is showing the potential for 30 cm or more of snow over portions of southern AB.. even Calgary could get a good dump!

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  27. Saw a couple of dust devils today in south Winnipeg.. one at the dump which picked up some debris. Good conditions for such things with very dry low levels, superheated air at the surface, strong sunshine and some high based cumulus clouds. Looks like our very dry weather with subfreezing dewpoints will be a thing of the past after this weekend with all the rain coming up and accelerated vegetation growth!

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