Brian's exclusive forecast for Baltimore, Annapolis, and northern Delmarva:
Tonight: Variable cloudiness with a low in the upper 20s to lower 30s.
Saturday: Cloudy with snow and sleet changing to rain. The high will be in the mid to upper 30s.
Saturday Night: Rain showers with areas of fog. The low will be in the mid 30s.
Sunday: Becoming mostly sunny and seasonably chilly with a high in the upper 30s to lower 40s.
Sunday Night: Variable cloudiness with a low in the upper 20s.
Monday: Sunny and cool with a high in the mid to upper 30s.
The extended forecast calls for a mostly sunny sky with milder temperatures on Tuesday through Thursday with lows in the upper 20s to lower 30s and highs each day in the mid 40s.
High pressure that provided sunny and cold weather for the Middle Atlantic states the past two days is now moving from the region and giving way to low pressure that will produce mixed precipitation in our region on Saturday. For the remainder of the overnight hours we can expect variable cloudiness with temperatures dropping into the upper 20s to lower 30s. A Winter Storm Warning is in effect for places like Hagerstown, Frederick, and Westminster where several inches of snow and ice may accumulate on Saturday. A Winter Weather Advisory is in effect for northern Maryland and for areas to the north and west of Baltimore and Washington. In Pennsylvania, northern New Jersey, and the Hudson River valley in upstate New York, a significant snowstorm is likely. Closer to the bay, an inch or less of snow and ice will transition over to a cold rain. The development of the system will feature one low moving northeast from the Tennessee Valley and a secondary low forming off the Delmarva coast. With fresh cold air in place over the region, precipitation on Saturday may begin as snow and/or sleet, but will transition to rain as warmer air moves in from the south. Secondary lows are not big snow producers in the Mid-Atlantic and high pressure over New England (a key ingredient to snowstorms in the Chesapeake area) will be moving away rather than holding firm. This scenario supports a mix to rain event for Annapolis. Additionally, when the primary low transfers energy to the secondary low, central Maryland is often in a zone where precipitation is light. Consequently, this Saturday's event will not feature heavy precipitation in the area. Our weather improves on Sunday with a clearing sky and seasonably cool temperatures. Even milder thermometer readings are anticipated next week with highs reaching the low to mid 40s on Tuesday through Thursday.
On the Maryland portion of Chesapeake Bay, a Small Craft Advisory is in effect from Saturday afternoon through Saturday night. Winds tonight will come out of the east at 10 knots with waves one foot or less. Winds on Saturday will come out of the east at 10 to 15 knots with gusts over 20 knots and waves from 1 to 3 feet. Visibility may be reduced in snow, sleet, rain, and fog on Saturday. Winds on Saturday night will come out of the east at 10 to 15 knots, but then shift to the northwest overnight with gusts over 20 knots. Waves will be from 1 to 3 feet. Visibility may be reduced in rain and fog. Marine information is provided only as guidance. Boaters should always stay tuned to the latest forecasts and advisories from the National Weather Service.
The average high temperature for December 13 is 46 degrees and the average low is 29 degrees. The records at Baltimore on this date are 69 degrees in 1889 and 7 degrees in 1962. Today's sunrise will occur at 7:18 and the sunset will occur at 4:44. 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.