The stretch of foggy mornings this week continues Thursday, and it will on Friday, too.
A weak high pressure system that has kept weather nice in the afternoons for the most part is keeping winds light. That, coupled with high dewpoints overnight, is making the fog build up as temperatures fall into the early morning hours, said Kevin Whitt, a meteorologist with the National Weather Service in Sterling, Va.
Dewpoints at BWI Airport have virtually matched the temperature as it drops overnight, with both at 58 degrees as of 8 a.m. Visibility had been as short as 1/16 of a mile in some parts of Maryland and Virginia, but it grew to about a mile at BWI as of 9:30 a.m., Whitt said.
The mist will be slow to burn off as winds pick up and the cool air close to land mixes with warmer air higher in the atmosphere. Temperatures are expected to reach the mid-70s, but dewpoints have remained around 60 so far this week, so humidity will remain, but not the fog.
Friday it will be more of the same, with a foggy start to one of the hottest days of the year for Baltimore. Temperatures are slated to reach the low 80s.
This weekend, there should be even more moisture in the air -- rainy days are forecast for Saturday and Sunday.