June 20, 2013: Quick nowcast on risk for SK/MB
Have a few minutes where I was able to look some things over this afternoon and write a quick update on storm potential for this afternoon in Saskatchewan and Manitoba. Current meso analysis shows stronger jet core of 40-50 kts pushing through WY/MT and water vapor imagery also showing an associated shortwave trough pushing through MT associated with this jet core. These two variables are expected to push into southwestern SK this afternoon and evening which will aid with the over storm initiation.
At the surface we have an occlusion from AB through SK with the warm front sitting well into ND. Models did struggle last night with how long overnight storms would last and to how far east they would progress. The squall line that pushed into southern MB this morning really put a halt on how far north that warm front would push thus hindering moisture return and instability to an extent (see first image below for current sfc analysis). But a peak at visibly satellite (second image, pink area shows convergence along the occlusion) shows decent clearing through central to southeastern SK and into ND which should allow for suitable airmass recovery, which is currently shown on SBCAPE meso analysis (last image at bottom). This showing a an area of about 1000 j/kg building into SK and area of 2000+ j/kg building into ND which should also begin to build in for the southeastern part of SK. As the upper level winds and shortwave begin to push into SK aiding overall ascent would expect surface storms to initiate roughly within the 3-6 pm CST timeframe and gradually push ENE eventually into MB in the evening. With the warm front sitting so far south I don’t think moisture will be suitable to allow for real low cloud bases but shear should be enough for some weak rotating updrafts. Greater risk for stronger supercells will be more toward the Estevan and Carnduff, SK region and even into the extreme southwest corner of MB. With elevated nature of these storms tornado risk is pretty small but could be moderately sized hail. Greatest risk I think will be in the area outlined in pink where some severe storms are possible this afternoon and evening.
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