Wednesday, September 14, 2011
Cold outbreak brings first lake effect of the season over southern Manitoba
The first cold outbreak of the season brought some lake effect showers yesterday through last night into this morning off the Manitoba lakes, with a few narrow bands of significant precipitation to the southeast of the lakes. Most of the precipitation fell as rain thanks to the 18C lake waters, however precipitation was mixed at times with ice pellets or graupel and even some wet snowflurries in some areas. The radar image to the left shows a 6 hour precipitation accumulation between 3 am and 9 am, and nicely shows how the main lake effect bands were oriented, with a NNW flow of 330-340 degrees bringing narrow bands of precipitation off Lake Manitoba and Lake Winnipeg. The bands produced 5-15 mm of rain off Lake Manitoba through the High Bluff-Elm Creek areas, about 5 mm in the Pinawa region, and 10-15 mm near Fischer Branch. 850 temps of -4C were moving over 18C lake waters to produce the lake effect, which was generally cellular and disorganized during the day, becoming more pronounced overnight. The bands weakened during the day Wednesday as a ridge of high pressure built in from the west.
Posted by rob at 3:49 PM