Typically, in the transition seasons (autumn and spring) the atmosphere is more prone to large mid-level cyclones in the Central and Northern United States. These can include large upper level lows, cutoff lows in the mid levels of the atmosphere, and phasing jet streams. So far this autumn season, we haven’t seen any large low pressure system which feature any of the above. That will change on Thursday and Friday as a large upper level system forms in response to shortwave energy dropping southeast from the Pacific Jet and energy in Northwest Canada. The system will strengthen and slow over the Central US, pushing a cold front towards our area this weekend. Until then, pleasant weather is expected Wednesday Night through Thursday. You can check the details on the storm system by checking out our Technical Feature.
Tonight: Partly cloudy, pleasant, temperatures in the mid to upper 50’s falling throughout the night. The winds will turn to south and east, bringing in an onshore flow overnight. Coastal areas will see more humidity and temperatures more near the upper 50’s even throughout the night. Cooler inland.
Thursday: Partly sunny, warmer ahead of an approaching storm system over the Central US. Temperatures will reach into the middle 60’s with afternoon sun. Feeling a bit warmer, with increasing dew points. Rain should stay to the west during much of the day, although by early evening we can’t rule out a shower or two across our far western counties in New Jersey and Eastern PA.
Look Ahead: Things take an unsettled turn Thursday Night into Friday. Instability increases and a large storm system approaches from the Central US. Chance of showers and thunderstorms will increase essentially from Thursday Night through Friday evening. The unsettled weather could continue through the weekend until the cold front crosses Saturday PM.