Low pressure will travel quickly from northern Arkansas to western Pennsylvania by later this evening and it will then trek across Pennsylvania early tomorrow. This storm track will first send a warm front through the region late tonight and that will then be followed by a strong cold frontal passage on Wednesday. As a result, steady, soaking rain will move into the NYC metro region shortly and that will last most of the night, but then the overall precipitation pattern will evolve into more of a shower/thunderstorm pattern very late tonight and early tomorrow and some of the storms that form can produce heavy rainfall. Also, there is a good chance for some thick fog to develop very late tonight and early tomorrow as temperatures actually rise overnight from the current readings to near or slightly above 60 degrees by midday on Wednesday. Widespread rainfall amounts from this storm will be in the 1-3 inch range throughout the Mid-Atlantic between now and midday on Wednesday so flash flooding is a concern. Clearing skies then set in for the holiday on Thursday, and it should stay dry on Friday and Saturday as well.