Brian's exclusive forecast for Annapolis: Mostly cloudy this afternoon and breezy with widespread showers and thundershowers. The high will be in the upper 70s to lower 80s. South wind 10 to 20 m.p.h. at times with a few higher gusts. Evening showers giving way to a mostly cloudy sky overnight and a low in the mid 60s. Winds shifting to the west at 10 to 15 m.p.h. On Sunday, morning clouds will transition to a mostly sunny afternoon and a high in the mid 70s. North/northwest wind of 10 to 20 m.p.h. expected. Looking ahead, Monday will feature bright sunshine and cooler temperatures with highs only in the middle 60s.
The main weather feature today is a cold front that will move from west to east and sweep across the Chesapeake Bay later this evening. Until the front passes through the region, gusty winds from the south will accompany a mostly cloudy sky. The clash of the cooler, drier air associated with the front and warmer, more humid air at the surface, will result in the development of widespread showers and thundershowers this afternoon. No severe weather is expected, but some storms could produce briefly heavy rain and gusty winds. Once the front clears the region on Sunday, cooler air will overspread the bay area from the northwest. The result will be clearing conditions throughout the day and a fresh northwesterly wind. Highs on Sunday will climb into the middle 70s, but Monday's highs will struggle to reach the upper 60s.
On the Maryland portion of Chesapeake Bay, a Small Craft Advisory is in effect today and tonight for gusty winds and reduced visibilities due to rain showers. Winds today will come out of the south at 10 to 20 knots (gusts over 25 knots) with waves 2 to 3 feet. Winds tonight will shift from the south to the north/northwest at 10 to 20 knots (gusts over 25 knots). On Sunday, winds will come out of the north/northwest at 10 to 20 knots (gusts over 25 knots.) Marine weather information is provided only as a guide. Boaters should always stay tuned to the latest forecasts and advisories from the National Weather Service.
The average high temperature for September 21 is 76 degrees and the average low is 56. The records at Baltimore on this date are 96 degrees in 1931 and 37 degrees in 1962. Weather data courtesy of the National Weather Service. For more weather updates, please visit my Chesapeake Bay Weather page on Facebook, and if you're heading to Ocean City feel free to check out my Ocean City MD Weather page on Facebook. You can also follow me on Twitter @chesbayweather.