March 22, 2011
Spring not only offers flowers, warmer temperatures, and a general sense of hope, but often times it comes with very active weather. This March, the Midstate has seen its share of active weather from heavy rain and flooding to early morning thunderstorms just this week. Tomorrow morning also brings more wild weather and another sure sign of springtime...a battle between two different air masses.
Cool Canadian air wants to continue to dominate our weather as it has for much of the winter. Meanwhile, warmer and juicer air from the Gulf wants to move in from the south and take over as we head toward warmer months. This battle will yield a tricky forecast going into tomorrow morning. Which air mass will win out? The set-up as it stands now can be seen below:
In between the cool air and the warm air lies a frontal boundary which is the focus for heavy rain, thunderstorms, and heavy snow depending on the location. This is a very active boundary and tonight it will move into Pennsylvania. While most of the precipitation will fall as rain for a large part of the viewing area, some spots north of Harrisburg could see a wintry mix overnight as temperatures fall going into the early hours of Wednesday morning. PrecisionCast highlights this event nicely below:
Northeast Pennsylvania and the Poconos stand to get as much as 6 inches of wet snow and sleet from this event. Notice how Harrisburg and points south have enough mild air in place to keep the precipitation as plain rain. However, northern areas could see some sleet and wet snow mix in from time to time early tomorrow morning. Accumulations shouldn't be much with the ground being plenty warm, but we promise to keep an eye on things heading into tomorrow morning.
Places like Williamsport and Scranton could get some late season snowfall accumulations. Southern areas see little if any accumulations. I would probably use Interstate 80 as a reasonable dividing line for this storm. Some northern spots like Mifflin, Juniata, and northern Dauphin county could see some mix, but hopefully little in the way of accumulation. Schuylkill and Berks counties could see some wet snow accumulation though and if conditions are just right, even southern areas could see sleet mix in from time to time.
Rainfall could be moderate with this storm. This will be relatively long lasting. Expect rain to develop after midnight tonight and continue until early Thursday morning. We might get some breaks, but this looks like a pretty prolonged event.
Many backyards stand to get between 0.75 - 1.00" of rainfall. This would be yet another significant rain event for our area this month. Flooding shouldn't be an issue this time around, but we have definitely had a wetter than normal March.
In summary, three points to make about this next storm:
1. This will be a rain storm for most of the area plain and simple. Don't expect a widespread mixed precipitation event.
2. The farther north you live, the better your chances to see sleet and wet snow mix in with the rain. While little accumulation is expected in our viewing area, this is a tricky forecast. Be prepared for things to change quickly tomorrow morning if enough cold air gets pulled into the region.
3. This will be a prolonged storm lasting through early Thursday morning. Rainfall will be moderate and this storm could end as a few snow showers early Thursday.
As stated above, this is a tricky forecast and a developing storm. Stay with us through the day and into tomorrow for the very latest. Thanks!