Wednesday Afternoon Technical Discussion

Synopsis

The weather is looking up for the next few days as high pressure builds into the area, but we will have to make it through tomorrow first. Tomorrow will again be bitterly cold with temperatures expected to barely reach 20. Looking on the bright side for tomorrow, no precipitation is expected throughout the commonwealth. A low pressure system will just south of the Mason-Dixon line and move up the coast just missing PA. After tomorrow warmer, however still below average temperatures will remain through Saturday in conjunction with mostly sunny skies for most of the state. Sunday will be a nice change of pace with above average temperatures near 40. Although warmer temperatures are in store for the weekend, the western third of the state will see a clipper system Saturday through Sunday bringing a rain/snow mix.

Short Term (Tonight up unti/ Thursday night)

A 500mb trough currently situated within the Northeast and Eastern Canada  is starting to push its way through Pennsylvania. The trough axis will cross through the state starting late tonight into tomorrow morning. The westerly winds that we are experiencing now will continue into tomorrow evening. In line with the westerly winds is a slow yet steady spell of cold air advection that will cause the entire state to succumb to below freezing temperatures for the next 36 hours. Temperatures will struggle to make it out of the 20s with some areas to the North facing temperatures in the teens. Clear skies at night will make for frigid overnight lows in the single digits.

Long Term (Friday morning through Sunday Evening)

The tail end of the 500mb trough is leaving the state below the freezing mark for the most part, howecver, clear skies and weaker advection will help the warming process on Friday. Most areas should be out of the teens for high temperatures and some areas toward the South will see highs in the 30s for Friday. The 18z WRF and the 12x GFS show a shortwave trough around 6z Saturday, with both spit out light snow showers for the western half of the state with the WRF showing less of a chance than the 12z WRF had. The chance of snow may be less now based on the update, but there is still a chance of light snow for Western PA. A 500mb ridge is on its way from the Western US, which will help warm the state going into the weekend, but both the WRF and GFS show the ridge flattening out just before it hits the Eastern U.S. the ridge moves in midday Saturday, allowing for sunlight to dominate heating and provide most of the state with highs in the upper 30s to the lower to mid-40s for Saturday and Sunday

Steve Engblom