Pittsburgh woke up Wednesday morning to fog and temperatures around 57 degrees, with visibility sharply reduced in some spots. The murky start should give way to a warm, partly sunny afternoon with a high near 79.
A Special Weather Statement from the National Weather Service was in effect through 9 a.m. Wednesday for patchy dense fog, especially in river valleys. Some locations could see visibility drop to zero within a short distance, so drivers should use extra caution during the morning commute.
Warm Through Thursday, Then Friday Rain
The fog is expected to lift before 10 a.m. Wednesday as light south winds develop. Wednesday night will stay mostly cloudy with a low around 62, followed by another mild day Thursday with partly sunny skies and a high near 82.
The pattern changes Friday as rain showers arrive later in the day. The chance of precipitation is around 80%, with about a quarter-inch possible; showers could linger into Saturday as temperatures fall to around 50.
What valley fog and climate normals tell us
The National Weather Service Binghamton office explains that valley fog can form on clear, calm nights as cooling air drains into valleys. That general mechanism does not establish what caused Pittsburgh’s fog Wednesday.
The National Weather Service Pittsburgh climate report lists September 30 normal temperatures of 70°F for the high and 50°F for the low. Those temperature normals offer seasonal context for the forecast’s warm Wednesday, but they are not a forecast and do not establish how typical Friday’s rain is.
Cooler Weekend Leads Into Chilly Start To Next Week
Saturday looks mostly sunny and cooler, with a high near 69 and a low around 50.
Tuesday should be sunny and cool, with a high around 60.
