Nature is Struggling to Swing Into SpringMarch 26th, 2013 at 9:38 pm by Don Paul under 4 Warn Weather
As forecast last week, conditions this week are a good deal less harsh. But daytime highs will continue to run below average for the remainder of the work week, with a temporary moderating trend during the weekend. The North Atlantic block which has forced the polar jet stream to buckle to the south from the northern plains to the mid-south and up through the interior of the NE is weakening, but not entirely dissipating. Some nuisance snow showers will show up Wednesday into Thursday. The high angle of the sun will likely mix the snow with some rain during the afternoon at lower elevations. After high pressure moves in to bring us a pleasant Saturday, a warming downslope breeze will develop Saturday night into Easter morning ahead of another cold front. While temperatures will move above average for much of Easter, rain showers will develop by afternoon. After that sharp cold front goes by, however, we take 2 steps back with a gusty wind and falling temperatures on Monday–and the redevelopment of snow showers. No major storms are in sight, but we’ll have to keep an eye out for lapse rates/instability over the Lakes early next week, as some lake effect cannot be ruled out. Temperatures will run below average during the work week.
In the longer term, ensemble means (European, GFS, and Canadian) all seem to show more “tolerable” temperatures further out in time. There are still no signs of a fundamental shift to a western trough/warming eastern ridge, but the flow does seem to become nearly zonal in the mean. This would allow temperatures to be closer to average. The MJO is favored to become somewhat less active, which would favor greater variability over the North Atlantic (source: CPC), and the AO and NAO stay negative, but at much less amplitude. The PNA is looking to be more neutral. In the mean, it looks like a flatter pattern. However, interactions with individual short waves–as always–cannot be seen in this time range.