All Signs Point to Milder Than Average…most of the timeFebruary 27th, 2012 at 9:47 pm by Don Paul under 4 Warn Weather
No, that’s not the Magic 8 Ball talking. But there are no signs pointing to colder than average weather around here; just occasional shots of seasonable temperatures more than balanced by above average temperatures the majority of the next 16 days. We may even get a few spikes of almost springlike temperatures, generally associated with the warm sectors of vigorous short waves/storm systems–as may be the case Friday and Friday night, for example. One of the main forecast challenges with a mainly west-to-east zonal flow is timing the arrival of embedded short waves, as well as predicting intensity and trajectory/paths for these lows. Beginning later Tuesday night, an area of low pressure headed toward the northern plains will advect warmer and eventually moister air aloft into our region. Some light snow may develop late Tuesday night, and the snow may pick up during Wednesday morning, with a transition to sleet and then just rain. Amounts should be modest, and there may be a little freezing rain before the final change for the afternoon to liquid. There could be a minor coating of snow preceding this transition, and the best chance for any freezing rain would be in sheltered valleys.
Another storm system to watch will be what is currently depicted in most models and various ensemble members as a deepening low which moves to our north during Saturday. As seen in Monday runs, this low could move into a climatologically favored position to produce strong to possibly High Winds on Saturday. While the Climate Prediction Ctr has listed this wind potential as a Hazard for our region, they’ve also included the chance for Heavy Lake Effect Snow to accompany the wind hazard. Right now, I’m just not seeing evidence of cold advection adequate to produce heavy lake snow, though some lake enhanced snow might develop Saturday afternoon. Of course, the Meteorologists here at 4Warn Weather will be keeping an eye on this system’s potential all week.
La Nina continued to weaken this past week. Even when the la nina colder anomalies disappear altogether (which won’t be too many weeks longer), there will be a lag period in which the impacts from la nina will continue to be felt well into the spring. The CPC long range ENSO forecast is still for neutral ENSO conditions to replace la nina into the autumn, although more ensemble members seem to be flirting with a weak el nino by autumn than had been the case a few weeks ago. Still, the most favored trend is neutral.
As for the MJO, it continues to be active and CPC expects that to continue for the next 1-2 weeks, without much further eastward propagation. That favors warmer than average temperatures in the east, and above average precipitation for the Great Lakes.