Foggy Start to the Weekend in Philadelphia, Followed by Rain and Possible Wintry Mix

January 27, 2024

Foggy Conditions Blanket the Region

Residents of Philadelphia and surrounding areas found themselves enveloped in a dense fog on Saturday morning, January 27, 2024, leading to limited visibility and hazardous driving conditions. The fog settled overnight, reducing visibility to less than a mile in numerous areas.

The National Weather Service (NWS) issued a dense fog advisory for Philadelphia, Delaware County, and parts of South Jersey, urging motorists to proceed with caution and reduce their speed. The advisory remained in effect until 10 a.m. In contrast to the foggy conditions in the southeastern part of the state, the skies were mostly clear in the Poconos, Lehigh Valley, and Chester County.

Explaining the Fog Formation

In a video segment recorded on Thursday, meteorologist Grant Gilmore provided an explanation for the persistent fog. He explained that fog forms when warm, moist air encounters a cold surface, causing the water vapor in the air to condense into tiny water droplets. These droplets remain suspended in the air, creating the dense fog conditions experienced in the region.

Weather Forecast for Saturday and Beyond

As the fog gradually dissipated throughout the morning, the weather transitioned into a cloudy but mild and dry day. Although sunshine was not expected, outdoor activities were still feasible. The high temperature in Philadelphia was forecasted to reach 49 degrees Fahrenheit, with slightly lower temperatures in the Lehigh Valley and at the Jersey Shore.

However, the clear skies were short-lived as rain began to spread over the area in the evening and was anticipated to persist through Sunday. The rain could be heavy at times, especially overnight into the early hours of Sunday morning.

As the rain moved offshore on Sunday night, cooler air began to move into the region. This could potentially lead to a change in the lingering precipitation to a wintry mix. However, it was unlikely that the cold air would arrive in time to produce any significant snowfall.

The following week’s forecast called for mostly clear skies, with highs in the 40s and lows in the 30s.

Seven-Day Forecast

  • Saturday: Clouds at night, rain. High 49°F
  • Sunday: Periods of rain. High 44°F, Low 43°F
  • Monday: Possible rain/wintry mix early. High 43°F, Low 37°F
  • Tuesday: Partly sunny. High 41°F, Low 30°F
  • Wednesday: Partly sunny. High 41°F, Low 32°F
  • Thursday: High 48°F, Low 32°F
  • Friday: Partly sunny. High 49°F, Low 37°F

For the most up-to-date weather information, residents are advised to stay tuned to local news broadcasts or check the CBS News Philadelphia app.