Special Weather Statement issued January 24 at 11:37AM EST by NWS

...Areas of Dense Fog for Portions of Our Region Today... As of 1130 AM, visibility across much of southeastern Pennsylvania is near or less than one quarter mile in fog. The lower visibility is being observed to the southeast of Reading and Allentown and just outside of Philadelphia. A Dense Fog Advisory is in effect until 2 PM where the lowest visibility is occurring.