Saturday, March 24, 2012

Cold front moving through Red River valley this morning with some rain and freezing rain..

A sharp cold front crossing southern Manitoba is bringing in much colder air this morning with temperatures dropping dropping below the freezing mark on gusty northwest winds. The front is accompanied by a band of rain that will be falling in subfreezing air, resulting in a period of freezing rain this morning as it passes through. About 5-10 mm of rain has fallen with the band with even some isolated thunderstorms occurring. The ground is warm enough from the mild temperatures of the past two weeks that significant icing should not be a major problem.. however some icing is possible on bridges and overpasses as well as sidewalks so be aware of the potential of some slippery conditions as you head out this morning. The band of rain will end by mid morning with drier air this afternoon, however temperatures will be back to normal values for this time of year.. which will be a bit of a shock after the abnormal warmth of the past two weeks. Seasonable temperatures will continue Sunday with mainly sunny skies, before milder but wet conditions move in by Tuesday.

7 comments:

  1. Man.....where did I put that winter parka and scarf. I need 3 pairs of mitts it is so cold out there.....LOL

    :P

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  2. Sure hope what the GFS is suggesting this morning is wrong. GFS showing temps. in minus teens for the second week of April, with over a foot of snow. Fingers crossed that's just a glitch in the model!!

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    1. That's a long ways away right now, I wouldn't hold my breath...

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  3. ..Talk about a shock to the system.

    The elevated showers and tstorms behind the cold front were hinted at (by the American models at least), although timing was off.

    With the early start to spring, a hard freeze could do a lot of damage. EC is riding with the SCRIBE output of -9 C for overnite. But American models show the calmest air up thru 925 hPa, off to our NW by dawn tomorrow. NAM shows 20 knots just off the surface thru 7 AM.. so potential is there for bursts of mixing.

    Clouds are the other wildcard.. low cloud is hanging on, as cold air passes over relatively warm, moist surfaces. Exception would be 'streamers' of clear air coming off the cold lakes. High pressure at the surface does not really build into S Manitoba, so those clouds have a better chance of surviving longer into the nite.

    Finally, models show the potential for high and mid level cloud to move up in the SW flow. The raw output from those models shows a more moderate -4 or -5 C overnite low. My gut feeling leans towards the warmer, raw output more than the MOS. I hope its proven right.. -9 C just feels too cold now!

    Daniel

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  4. Agree with your assessment Daniel.. I think -9C would be a worst case scenario with skies clearing out and winds decoupling. Ground temperatures are more like mid or late April rather than March, so that should help us from radiating too much as well. Note that today was our first below freezing temperature since the morning of the 15th.. 8 straight nights above zero. It's actually a good thing that we're getting some cold temperatures to slow down nature's desire to start the growing season too soon.

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  5. That's true Rob. Some cold would be good to put the breaks on all the greening.. as long as its not too extreme ;)

    Daniel

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