What type of weather front would be responsible for the following forecast: "Increasing cloudiness and rising temperatures today with a high of 54˚ F. Steadily dropping air pressure. Possibility of showers and thunderstorms this evening. Southwesterly winds with gusts up to 30 mph shifting northwesterly by tonight. Temperature dropping into the mid-thirties by tonight with a low of 25˚ F early tomorrow morning with clear, calm skies by 10:00 am.