Monday, March 23, 2009

Colorado low to bring round two of precipitation over southern MB

An intense low over the central plains will be moving north into Minnesota overnight and Tuesday bringing another round of precipitation over southern MB beginning tonight and continuing into Wednesday. Precipitation will move in as rain over the Red River valley and southeast MB tonight into Tuesday morning before it changes to snow in the afternoon or evening. There may even be a period of freezing rain during the transition from rain to snow Tuesday. Rainfall amounts from this second round of precipitation will likely be in the 10-20 mm range with locally higher amounts of 30 mm possible near the US border. Snowfall may accumulate 5 to 10 cm late Tuesday through Tuesday night into Wednesday. Snowfall amounts may be higher if the transition to snow is earlier than currently expected. Further west, the air will be cold enough for the precipitation from this system to fall as snow Tuesday, with significant amounts of 20 to 25 cm possible in areas west of the Red River valley. Winter storm and weather warnings are in effect for much of southern MB for this system.

Meanwhile, the province of Manitoba has released its updated flood outlook for the Red River today. It hasn't changed it's earlier forecast anticipating a 1979 level flood but still short of 1997 levels.

55 comments:

  1. I cannot help thinking the province may be underestimating crest levels a bit.

    Quote:
    "The North Dakota portion of the Red River watershed received five to 10 mm (0.2 to 0.4 in.) and some areas in the Minnesota portion received 40 mm (1.6 in.)."

    This does not match well with RADAR estimates from NWS available in this nice graphic:
    http://www.crh.noaa.gov/images/fgf/Top24HR_QPE_March23_2009_Pop.png

    Do they know for a fact that RADAR overestimated?

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  2. Amazing!
    In south Dakota the thunderstorms are right up against a raging blizzard!

    Within 50 miles of travel distance you go from a blizzard to a thunderstorm !

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  3. Rob...

    Did PASPC do a sounding today? If so, what was the temperature at 850mb. If not, do you have any idea as to what the temperature is at 850mb?

    Thanks

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  4. There are not enough upper air stations across the N Plains/ prairies... in the absence of radiosonde launch at Winnipeg, one has to rely on model soundings. I imagine they have access to one from GEM along with RUC...

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  5. I think they may also have access to data from cargo planes aswell

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  6. I was a looking at the radar earlier and was wondering where are this heavy rain and snow will becoming from.
    I mean there was thunderstorms in Nebraska but that was far away.....the *poof* all of a sudden look at all the rain that has developed south of Fargo!!

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  7. I must admit I was surprised by the province's unchanged flood outlook, but supposedly even with this week's pcpn levels, and a few extra storms over the next two weeks, we'll still be below 1997 levels. I'm not a flood forecaster, so I'll leave it up to their expertise. Note they will be providing daily updates now, so we'll see if their predictions change, especially considering what will be transpiring south of the border.

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  8. Rob I have a question!!!

    Do you think that Winnipeg will change over to snow earlier than forecast!

    Right now the temperature is already down to 2 C

    Could there be a remote chance that it could be snowing when we get up in the morning??????

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  9. I don't think the office did a release today.. but as Daniel said, we have access to aircraft soundings (ACARS) which are pretty good.. (password protected data)

    In the meantime, you can get updated MAPS upper air soundings updated from the RUC at..

    http://www-frd.fsl.noaa.gov/mab/soundings/reply-skewt.cgi?data_source=MAPS&lon=-104.67&lat=39.87&airport=cywg

    The 850 mb analysis this evening should also give you a pretty good idea. Looks like we're at around +3C at 850 mb this evening. Upper air analyses will be critical tonight and Tuesday to determine precip phase over southern MB. GFS and NAM have Winnipeg changing to snow by daybreak, while the GEM is warmer, and has Winnipeg in rain before changing to snow by late afternoon. Note that we could also have a period of freezing rain if those northerly winds bring subfreezing air at the surface while it's still warm enough aloft for rain. Tricky forecast for sure.. timing of phase transition will have big impacts on snow/rain amounts.

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  10. The fog is getting pretty thick out there also!
    Visibility is down to 800 m at the airport!

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  11. Intellicast RADAR for N Plains depicts rain/snow line from roughly Bismark to Brandon (extrapolating).

    Certainly going to be tricky tomorrow. The GFS progs some warmer 850 hPa air to 'dumbbell' back into SE Manitoba/NW Ontario border by tomorrow.

    As a result the rain/snow line will likely move eastwards tonite and may stabilize somewhere around Winnipeg by morning. There is a chance of it actually bisecting the city (!!). By early to mid afternoon more cold air starts pushing in and the boundary moves further east.

    That's my best guess...

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  12. Thanks for the link, Rob...that will certainly come in handy tomorrow.

    The NAM indicates the temperature should be -1.5C right now, the MAPS data shows it being +3. That would mean that it could be late afternoon/evening before we see the changeover.

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  13. Rob

    Their calling for 10cm snow overnight on Tuesday and then again periods of snow on Wednesday. How much snow will fall during the day any ideas?

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  14. I mean Wednesday Day.

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  15. The low will be moving off into NW Ontario by then.. perhaps another 2-5 cm for Winnipeg, 5-10 cm possible near the Ontario border.

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  16. Nice rain band between Fargo and Grand Forks. Moving north at approx 30 kmh. I suspect it will reach Winnipeg by 3 am weakening to drizzle/ light rain.

    RUC wants to bring thru 0 C isotherm at 850 hPa by 7 am just as lift and precip band re-intensify... ughh, I hope its wrong. If it verifies rain snow line may get hung up between Winnipeg and Steinbach...

    Wildcard is the warmish/moist ground... snow will not stick at first, this complicates any guess of accumulation. Good nite, I have spent too much time for this storm already lol.

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  17. UNREAL
    Rapid city SD has recorded a wind gust tonight of 74 mph.
    Whoa .....now that's a blizzard!

    Were they just not at 76 F the other day!!!!!!

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  18. Winnipeg upgraded to Winter Storm Warning!!!

    Temps are only hovering above the freezing mark so the change over should happen soon!

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  19. Zero degree line at the surface running from Selkirk through Rosser to Fannystelle down through Morden-Winkler area. Rain changes to freezing rain west of this line for about 50 km then changes to snow west of that. Portage LP was reporting freezing rain at 6 am and has now changed to snow.

    Looks like Winnipeg will see a period of freezing rain shortly as our temperature drops below freezing (by 7 am or so?) then likely changing to snow by mid to late morning. 5 cm possible by the drive home.

    Rainfall amounts have been meager with this band overnight.. only about 2-5 mm so far that I've seen.. much less than the models were indicating. Heavier amounts of 10-25 mm south of the border.

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  20. Rain and ice pellets in Charleswood as of 6:45 am.. temp 0.1C..

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  21. Rob... does your poll for the amount of precip that will fall from Sunday to Wednesday include snow I assume?????

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  22. Yes.. rain and any snow through the end of today. My guess is that we'll be looking at the low end of that range.. perhaps 15 mm.. a lot less than the models were showing earlier this week. (I've had about 10 mm in total so far)

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  23. Snow has just started on the west side of the city!
    Mind you it is mixed with rain and ice pellets!!!!

    What a a mess!

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  24. Pretty much all snow now in Charleswood as of 8 am, some ice pellets.. visibility not too bad, trace snow accumulation... about 6 mm of rain overnight.

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  25. It went from a "spring" look to a winter wasteland in matter of 15 minutes.....*sigh*

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  26. As of 9:30am it looks like the precipatation is going to break off for awhile as the system rotates.

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  27. Looks like about 10 mm of rain and ice pellets/snow across Winnipeg so far this morning.. on top of the 5-10 mm yesterday. Two day totals so far about 15-20 mm across Winnipeg/RRV.. with a little more snow to come back later today into tonight and Wednesday.

    By the way, the pcpn gauge at Winnipeg airport is overestimating rainfall these past two days due to a nipher shield still attached to the gauge. It has measured over 30 mm over the past two days which is about double everyone else. Something to be aware of..

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  28. a Flash Flood warning as follows for Crookston issued at 9:51

    * AT 951 AM CDT...LAW ENFORCEMENT REPORTED AN ICE JAM ON THE RED
    LAKE RIVER IN THE CITY OF CROOKSTON. THIS HAS CAUSED THE RED LAKE
    RIVER TO RISE TO NEAR THE TOP OF THE DIKES IN TOWN. EVACUATION
    HAS BEEN ORDERED BY LAW ENFORCEMENT.

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  29. Are they still expecting another 25mm for RRV south of Pemina. I am losing confidence in that Flood Forecast despite the locally lower pcpn than forecast. Red Lake River has already hit a New Record at high landing this am and downstream Crookston has topped the dikes.

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  30. Rob do you think the snowfall totals for Winnipeg are now going to go down or do you think that EC still has it right with 5cm tonight and another 5-10cm tomorrow.

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  31. Deformation zone has backed off the NW... this is where the models painted the best baroclinicity and forcing at 700 hPa. Models hinted all along that Winnipeg could end up in stratus filled dry slot...

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  32. Daniel

    It almost seems to be the story of the entire winter for Winnipeg

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  33. Lol... yeah its true, Winnipeg was often bypassed this winter.

    From looking at RUC, warmer 850 hPa temps start to back in from the east by late afternoon... surface temps likely will stay below zero with the northerly flow. I think potential is there for light freezing drizzle by rush hour.

    Gem and GFS then hit us with another blob of precip overnite.. this would be snow. It seems to be associated with the 700 hPa low and what looks like decent frontogenetic forcing.

    But here I am guessing... because by looking at thermal gradient at 700 hPa one can only crudely estimate the forcing.

    If we had access to quantitative forecasting tools such as Q vector analysis... mid level forcing would be a lot easier to pick out.

    EC forecast discussions etc are necessarily more qualitative.

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  34. So Rob.....what do we win for guessing the amount of precip in your poll....????

    A trip down south ,somewhere warm???

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  35. getting reports of lots of water in the red lake basin east of Grand Forks up to Red Lake MN itself...ice jams occurring as well.. Lots of water too south of Fargo yet to get into the Red River as fields and towns are surrounded by water... thinking is more and more that all 3 bridges in GF will be closed as 52 ft looks more and more likely.

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  36. Was it expected for this initial precepitation to move as far north as it did? Usually it seems to stall and then counter rotate and move back over us but it seems to keep moving north as it counter rotates. I guess their is more comming from the south then or is the blip on radar going to move back down after the rotation?

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  37. Deformation band associated with mid level forcing was progged to move NW of Winnipeg as discussed.

    This band will weaken and wash out. As main 700 hPa low moves towards SE Manitoba tonite.. strong frontogenetic band redevelops as the low starts tapping cold arctic air streaming down form high. It is already forming in central Minnesota.

    Expect it to intensify and back into SE Manitoba overnite. GFS and GEM hit SE Manitoba and RRV with 10-15 cm of snow overnite.

    Uncertainties... how far NW will this band set up.. and freezing rain potential.

    Freezing line is running right now from Emerson thru La Broquerie to Great Falls. Rain/snow line (850 hPa isotherm) running about 100 km west of that. Model sounding shows good inversion at YWG (0 C @ 850 hPa).

    As that forcing moves in from the SE.. RUC depicts 0 C at Winnipeg and points SE until atleast 10 pm. Therefore there is initial risk of freezing rain for a few hours before precip changes back to snow.. maybe 10 cm worth..

    That's my guess

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  38. I am surprised EC did not issue at least a freezing rain watch for SE Manitoba.. what is your take Rob?

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  39. Daniel..

    I think the winter storm warning includes a freezing rain warning/advisory.

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  40. That's correct.. a winter storm warning is issued for snow plus another severe winter element.. such as freezing rain. EC does not have a freezing rain watch..just a winter storm watch which can be upgraded to a freezing rain warning if significant freezing rain is expected. In tonight's case, I guess they expect most of the precip over SE MB to turn to snow this evening, with a period of rain or freezing rain to start. Note that GFK is now reporting freezing rain.

    By the way, I recorded 6 mm of rain overnight, and 7 mm of melted snow/ice pellets this morning for a storm total of 13 mm today. That puts me up to 19 mm since Sunday night. A lot of standing water in Charleswood area.. local city councilor Bill Clement says it's the worst he's ever seen around here.

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  41. Daniel P. asked..

    >>So Rob.....what do we win for guessing the amount of precip in your poll....???? A trip down south ,somewhere warm???"

    Well.. I was prepared to do that.. but with the economy the way it is, I had to scale back this year. So I just will give you a pat on the back for a job well done! By the way, the correct answer to the poll was 15-30 mm, with the Forks reporting around 21 mm since Sunday night. This is about half of what most models were suggesting prior to this event, at least for Winnipeg, but within range of the ensemble estimates.

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  42. That area of rain over northern MN is showing very little motion northward.. it's mainly moving west around the upper low. Looks like only extreme SE MB will get clipped by this area of pcpn area as the upper low moves over northern MN tonight.

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  43. will that area of precip hit Winnipeg? The models show it hitting us. If not the models are way off!!!

    So much for a decent snow event for us.

    Damn!

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  44. Rob

    I don't know about the worst, but like the provincial flood forecast the late seventies (78 or79?)produced huge lakes in Charleswood with the front stair landings being the first above water visible object in most yards between bemont school and Roblyn Snow covering fences 6 feet high in most yards on April 14th was gone by April 17th I recall.

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  45. Thats Beaumont School.

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  46. ROB Do you or anyone know why all of the Weather Warnings are issued All Caps in a Mono spaced Font (very difficult to read)??

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  47. Mid level/upper low would have to move a couple of hundred km further north for Winnipeg to be affected. GFS still progs 700 hPa low to move into NW Minnesota by dawn tomorrow. RUC is a bit further SE with that feature... for right now its pretty much stationary.

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  48. Warnings on the EC's Weatheroffice website appear in upper and lower case letters if you prefer it that way. I prefer using the College of Dupage website for warnings because they are on the web faster, are more complete, and appear just as they are produced from the weather office, which are all caps and in an easier to read format (especially critical in summer severe weather)

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  49. Did I read that right? Most of the snow will now miss us? At least that is what most are thinking?

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  50. Daryl..

    Yeah, it's looking that way. Radar and satellite photos show the area of pcpn over Minnesoa and ND is pretty much staying wrapped around the upper low well to our southeast. Southeast MB may get clipped overnight into Wednesday as the upper low moves north overnight, but it's looking like Winnipeg will miss much of the heavier snow (which is fine by me!)

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  51. Btw... another Colorado low is possible Mon/Tues somewhere over the N Plains ... I already have storm fatigue.

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  52. Daniel

    Please don't tease me. I don't know if I can take another miss. LOL

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  53. Yeah, no kidding.. these past few days have really tested our met skills. Sure has been interesting though..

    By the way, latest models keep bringing snow back over Winnipeg/RRV overnight/Wednesday as upper low moves almost due north towards International Falls and we get wrap around snow on the western flank. Latest radar showing some echoes to our east trying to work their way towards us. Perhaps this area will fill in overnight into Wednesday morning as upper low moves north. I still think the bulk of snow will fall east of the city, but Winnipeg may get 5 cm overnight/Wednesday..

    Note that winds are quite strong tonight through Wednesday morning which will cause visibility problems with any snow that does fall.

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  54. Freezing drizzle here...significant ice accumulations on driveways, sidewalks, trees, and some highways. Fire trucks have been out many times tonight.

    Brett Anderson from Accuweather is calling for 15 to 30cm of snow for Winnipeg. I don't have the foggiest idea where he got those numbers from. In any case it does appear that Winnipeg will get more than nothing tonight, I think 5cm sounds like a very good "guess". I say "guess", because the models have been so terrible lately any prediction is basically a guess at this point.

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  55. Still getting freezing drizzle here as well.. even getting some power bumps now and then due to those high winds and icing.

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