March's Glory On Full Display
After Monday's mild weather and bountiful sunshine we will begin to feel the impacts of the next storm system across the Mid Atlantic. A cold front (associated with a low crossing through the Great Lakes and into Canada) will be crossing north of Philadelphia while low pressure organizes and intensifies in the Ohio Valley. While the Ohio Valley low will dominate our weather by keeping Philadelphia in the warm sector through Tuesday and Tuesday night, uncertainty exists about how far south the cold front slips for our friends north of Philadelphia.
March and April are notorious for back door cold fronts that can slip through the region, resulting in large disparities in temperatures over a 40-50 mile range as locations north of the back door boundary are stuck in the 30's and 40's with clouds and an east wind while those south of the boundary enjoy mild 60's. While both the GFS and NAM computer models agree that the boundary should stay north of Philadelphia on Tuesday, with Blue Mountain being the consensus boundary between cool east winds and warm south winds, the NAM is clearly showing a more aggressive cold scenario for the Poconos, with temperatures in the 30's in the Poconos according to the NAM while the GFS has temperatures in the mid 40's.
Just a slight twenty mile shift south in the boundary between what the GFS and NAM have forecast brings colder air into Allentown. Since we're in early March cold air still has a fair bit of push to it and could easily slip a bit farther south than the model thinking.
In either case, the cool Tuesday to our north or far north will be replaced with a warm up on Tuesday night as the Ohio Valley low tracks up the Appalachians on Tuesday night and early Wednesday. With Philadelphia in the warm sector periods of rain and storms will move through the region. There is not much agreement on model precipitation, with the GFS more rainy than the NAM for Philadelphia. (.81" to .32" between the two models). Some regions will see about an inch of rain but this storm looks to bring scattered lines of showers and thunderstorms through the region, with the heaviest activity to the north of Philadelphia.
The GFS suggests two inches of rain for Allentown from this storm system and an inch and a half for Reading, with the NAM suggesting about half that amount for both locations. It's possible we could see some flood watches up for Tuesday night and early Wednesday across Eastern Pennsylvania from this storm system as it brings heavy rain to parts of the region.
Another thing to watch out for is severe weather Tuesday night/early Wednesday. The Storm Prediction Center has our region in a Slight Risk for severe weather three days out from the forecast event. The Storm Prediction Center is throwing around the potential for a tornado or two within the storms and has a 15% potential for severe weather across much of the area.
March and April are notorious for back door cold fronts that can slip through the region, resulting in large disparities in temperatures over a 40-50 mile range as locations north of the back door boundary are stuck in the 30's and 40's with clouds and an east wind while those south of the boundary enjoy mild 60's. While both the GFS and NAM computer models agree that the boundary should stay north of Philadelphia on Tuesday, with Blue Mountain being the consensus boundary between cool east winds and warm south winds, the NAM is clearly showing a more aggressive cold scenario for the Poconos, with temperatures in the 30's in the Poconos according to the NAM while the GFS has temperatures in the mid 40's.
Just a slight twenty mile shift south in the boundary between what the GFS and NAM have forecast brings colder air into Allentown. Since we're in early March cold air still has a fair bit of push to it and could easily slip a bit farther south than the model thinking.
In either case, the cool Tuesday to our north or far north will be replaced with a warm up on Tuesday night as the Ohio Valley low tracks up the Appalachians on Tuesday night and early Wednesday. With Philadelphia in the warm sector periods of rain and storms will move through the region. There is not much agreement on model precipitation, with the GFS more rainy than the NAM for Philadelphia. (.81" to .32" between the two models). Some regions will see about an inch of rain but this storm looks to bring scattered lines of showers and thunderstorms through the region, with the heaviest activity to the north of Philadelphia.
The GFS suggests two inches of rain for Allentown from this storm system and an inch and a half for Reading, with the NAM suggesting about half that amount for both locations. It's possible we could see some flood watches up for Tuesday night and early Wednesday across Eastern Pennsylvania from this storm system as it brings heavy rain to parts of the region.Another thing to watch out for is severe weather Tuesday night/early Wednesday. The Storm Prediction Center has our region in a Slight Risk for severe weather three days out from the forecast event. The Storm Prediction Center is throwing around the potential for a tornado or two within the storms and has a 15% potential for severe weather across much of the area.
Tags:
