Saturday, March 14, 2009

Nice thaw on the way

A nice thaw is on the way over southern MB after last week's deep freeze left many wondering if spring would ever arrive this year. After flirting with the freezing mark yesterday, temperatures should get to about +1-2C today, and +4-5C for Sunday and Monday. This will start some significant melting of the snowpack over southern MB, so be prepared for sloppy streets and walkways for the next few days. Somewhat cooler weather is on tap by midweek into next weekend with models hinting at another spell of above normal temperatures next week. Has spring finally sprung across the Praires?

18 comments:

  1. Rob

    Any hints of any large storms in the next couple of weeks?

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  2. Nothing major that the models are hinting at this point. Our upper pattern over the next week or two will be dominated by a zonal flow or upper ridge to the west.. which is not conducive to big storms developing over the US plains.

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  3. Beautiful day out there.. finally feeling springlike. Check out International Falls.. +12C today, just 5 days after getting hammered with a 30 cm blizzard! +8C in Pinawa and Kenora. Amazing what those forests will do this time of year!

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  4. Beautiful day indeed. Wind shift line literally along the N perimeter hwy. Main thermal gradient up around central Manitoba however. Low in Alberta is progged to push stationary boundary northwards as a warm front tomorrow. We should be in a decent SSW flow with 850 hPa temps around 4-6 C. Bare ground and mixing up to that level would yield highs between 15-20 C! As it is I'm sure we will see 10-15 C in heavily forested areas of Minnesota and SE Manitoba. Temps may stay above freezing Sunday nite as we get into the warm sector of that Alberta low. Cool front progged to pass Monday afternoon.

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  5. Look at the system on the 00z GFS for next Saturday. The 8 Day run from now. Monster storm system. Looks tornadic in areas like South Central Dakota. Triple point set up with an amazing veering profile would mean a good chance of tornadoes too. I doubt this will materialize. It also shows mega precip for us in South Man too. But hey, it's nice to see a summer storm system being hinted at this early in the year.

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  6. That system looks very interesting for now. Active SW flow aloft starting the end of next week. GFS advertizes very strong low level jet advecting copious moisture northwards. Trajectory of low is from Montana and not Colorado however. Lets see how other operational models and ensemble members handle this system.

    Strong southerly flow down at Fargo with gusts up to 40 kmh today. In fact temps stayed above zero all nite there.. lots of melting I'm sure. Stronger flow finally materialized up here mixing out all that fog and stratus.

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  7. That system appears to be the result of the GFS digging the west coast trof deeper than yesterday's run.. we'll see if that holds over the next few runs.

    Up to +9C at my place today.. warmest since early November. A few degrees cooler at the airport.. most sites in the city were up to +8C today.

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  8. Weathernet is calling for some significant moisture for sunday with 10mm of rain and 5-10cm of snow. I guess they are looking at the same system that you are out of Montana

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  9. Wow.. interesting pattern emerging. Arctic front lined up right along the TransCanada hwy from BC to NE Ontario. Do you ever remember seeing something like this before Rob? Poor Brandon stuck with a NE flow and -6 C .. hard to believe.

    Flow tonite will go pretty slack so temps may slip below freezing. However dewpoints are fairly high (1 to 2 C) from the all the snow melt. Therfore temps may not drop below freezing until farily late.

    Tomorrow still looks balmy.. warm 850 hPa temps of around 6 C and good mixing potential with a SW flow transitioning to W by around mid-afternoon. I am hoping for double digits but remaining snow pack may inhibit warming.

    After a brief shot of high pressure.. strong thermal gradient along int'l border becomes re-established. Gulf opens up and potential is there for considerable precip if pattern verifies (big if). Interesting how the storm track/ temp gradient has migrated north from the central plains. As Rob has mentioned in the past, during La Nina springs.. we are usually on the cold side.

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  10. Should that storm come true, there will be huge problems. I would go so far as to say that the flood will be worse than 1997 should that happen. The current forecast shows 25 to 50cm of snow for Manitoba and northern ND, MN.

    I am liking these +9C temperatures. I am also hoping for double-digits tomorrow!!

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  11. Daniel..

    Not to that extent.. but sometimes we see that set up over the eastern Prairies.. except usually Winnipeg is stuck on the cold side of the frontal boundary. Nice to be the right side of the front this weekend.. especially with our snowcover.

    I agree that it should be another nice one tomorrow.. The forecast high of +4C seems a little on the cool side given what we saw today. I'm thinking we should get at least as mild as today.. +6 to +9C over the city, especially if we're a little milder tonight as you suggest.

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  12. The 12z run still shows a major storm system for the end of next weekend. Huge impulse slams the West Coast...models show tons of moisture.

    If this system does materialize, the flooding probably will surpass '97 levels. That is the worst time for this precip. The spring melt has already started in ND, and with the brief cooldown this week, and the warming to the end of the week, and then that big snowstorm; this will be the straw that breaks the camels back. It's still ways away, but models are good at predicting large systems this far out. There WILL be a Low that spins up somewhere in the Northern Plains...where and how strong? are the questions to ask now. I think using the 500mb or the 250mb level for the long range is good for strong storm systems that crash onshore.

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  13. The models are showing are not showing a single day with a below freezing high temperature in the American RRV. On Wednesday Fargo will probably still be +2 to +4. I expect that most of the snow will be gone in southern North Dakota by this time next week. Manitoba will also be quite warm, with only a day or two with a below freezing high this week.

    If we do see the temperatures that are currently forecast, it would mean an extremely rapid melt with little time to prepare for flooding south of the border. If we get this storm next weekend, places like Fargo may be in very deep trouble.

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  14. The 97 Storm fell following a 10 day warmup which peaked at 6c March 26th Eight days before the storm Even with all that melting the refreeze and storm precip April 4to 6th was the major cause of the flood

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  15. The Free Press is reporting that Manitoba Water Stewardship will be releasing its latest flood forecast today, rather than Friday, because of all the new found interest around the flood situation.

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  16. Storm still looks on track for this coming Sunday into Monday. Heavy Precip and really warm temperatures, and plenty of moisture.

    Looks like a severe thunderstorm threat for areas as far north as South Dakota too. Spring is going to come in with a mighty roar based on the latest model runs...

    People in the RRV will def have to monitor this situation, this will likely seal the deal concerning the 1 in 3 chance of a repeat of '97 in Fargo, ND.

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  17. Lift from an upper wave over Saskatchewan and 700 hPa moisture has produced persistent mid level clouds over Winnipeg. Back edge of cloud field keeps redeveloping.

    Model soundings show 11 C at 925 hPa. With sun and SW flow we could easily crack 10 C even with snow cover... too bad.

    Trough right over RRV. Not sure if low level westerly flow will help much for clearing. Aforementioned sounding show air below 850 hPa is extremely dry already.

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  18. Special Weather Statement issued for the American Red River Valley. It states that the Red River will begin flooding south of the border by next weekend.

    Temperatures are supposed to stay above freezing indefinitely there, so they will be in big trouble, since they haven't had much time to prepare for the flood.

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