Maybe you’ve noticed that the media weather forecasts have been hinting at a snow storm for this coming weekend. So what about this?
The short version is that the European model (ECMWF) is showing the development of a deep coastal storm in the Friday night through Saturday timeframe. However, the latest US models show less amplification and a weak storm that scoots out to our south. The newest statistical experimental models show some low probability storm and the probability has diminished over the past few days.
So the bottom line is that we simply don’t know yet. I know the ECMWF tends to be better than the GFS in the long range especially in winter, but I’m not convinced about this possible storm for Saturday just yet. I’ll keep an eye on it. Stay tuned. I think we’ll have a better handle on it within the next model runs tonight.
The statistical models have been suggesting the possibility of a secondary low pressure system developing off the coast along a cold frontal boundary. The deterministic models ( GFS, NAM) haven’t shown anything until today. The general trend has been for the secondary low to form too far north and east to give any significant snowfall to our area, but the models are showing a light coating.
Below are the current low pressure center possibilities, based on different GFS possibilities (“perturbations”). Most are somewhat north and east.
The afternoon run of the NAM just became available. QPF values for PHL are now over 0.5 inches water. The critical temperatures of the upper atmosphere are now not as warm as the earlier run from PHL and westward. Still slightly warm for dry snow—some sleet or ice pellets will mix in reducing snow totals. Approximately 3-5 inches possible for PHL and immediate west is the current call.
The afternoon model runs are not the best, since they don’t incorporate new radiosonde upper air data. (That’s those weather balloons.) Will have a better handle on snow totals with the evening runs. Will update by about 9:30 PM tonight.
