Synopsis:
Mid-latitude cyclone to bring nasty storms to PA Monday evening into Tuesday AM. High pressure rapidly builds in behind it for the middle of the week. Dry but cooler. Weak system to bring scattered showers to PA on Thursday.
Models used: 12Z NAM & GFS; MOS
Short-term:
The system that brought the severe weather is sliding eastward. Look for sunny skies during the day with temps in the upper 70s -> mid-80s and dew points well into the 60s to provide enough destabilization. Surface-to-1-km SR Helicity values of 150-200+ m^2 per s^2 should provide enough shear to allow multicellular storm clusters and a squall line to develop and trek across western PA. (We need shear to be at least 75% greater for supercells to form.) After hitting the Appalachians, the storms should weaken not only because of the effects of the mountains but also because they will arrive in central PA around midnight with instability decreasing. Heavy rain and gusty winds should spread into central PA and heavy storms will also affect eastern PA overnight.
Long-range:
High pressure will be on the cold front's heels, influencing our weather for Tuesday. Frost is possible north of I-80 and west of I-81 as lows that night reach the mid 30s.
A weak low is forecast to slide by during the later part of the week, bringing showers.
-Jaron Breen
Hope everyone lived through the storms in the Plains states last night and yesterday afternoon. We wish a speedy recovery to all those in the affected areas.
Mid-latitude cyclone to bring nasty storms to PA Monday evening into Tuesday AM. High pressure rapidly builds in behind it for the middle of the week. Dry but cooler. Weak system to bring scattered showers to PA on Thursday.
Models used: 12Z NAM & GFS; MOS
Short-term:
The system that brought the severe weather is sliding eastward. Look for sunny skies during the day with temps in the upper 70s -> mid-80s and dew points well into the 60s to provide enough destabilization. Surface-to-1-km SR Helicity values of 150-200+ m^2 per s^2 should provide enough shear to allow multicellular storm clusters and a squall line to develop and trek across western PA. (We need shear to be at least 75% greater for supercells to form.) After hitting the Appalachians, the storms should weaken not only because of the effects of the mountains but also because they will arrive in central PA around midnight with instability decreasing. Heavy rain and gusty winds should spread into central PA and heavy storms will also affect eastern PA overnight.
Long-range:
High pressure will be on the cold front's heels, influencing our weather for Tuesday. Frost is possible north of I-80 and west of I-81 as lows that night reach the mid 30s.
A weak low is forecast to slide by during the later part of the week, bringing showers.
-Jaron Breen
Hope everyone lived through the storms in the Plains states last night and yesterday afternoon. We wish a speedy recovery to all those in the affected areas.
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