Baltimore residents should keep their umbrellas handy, as the National Weather Service Baltimore MD/Washington DC forecasts an increased likelihood of showers and thunderstorms through the end of the week. According to their latest Area Forecast Discussion, high pressure will be moving offshore, making room for a slow-moving cold front to bring a series of low-pressure systems across the region. This change in weather patterns is expected to commence today and persist into the weekend.
The forecast anticipates patchy fog to lift by this morning, especially in areas that experienced rainfall yesterday. As the day progresses, a lee trough is expected to form along the Alleghenies/Appalachians, acting as a catalyst for convective development. 500 mb flow will continue to remain out of the west with south to southwest flow at the surface, the National Weather Service reported, suggesting organized storm movement east of the mountains. Some storms may be capable of producing damaging winds and heavy rainfall, with 2 to 8 pm being the highest window for convective development.
Looking ahead into the midweek, Wednesday through Thursday night should see a continued influence of the troughing and the cold frontal boundary. High temperatures are expected to be slightly lower due to increased cloud cover, with readings in the upper 70s and low 80s, while high moisture in the atmosphere sets the stage for potentially heavy rainfall. Given recent drought concerns, the rain could be a welcome relief to parched areas, although severe weather, such as gusty winds, may accompany some storms.
For aviation, VFR conditions are anticipated to prevail through this afternoon across the terminals, with increased convective activity later in the day. The advisory details a window between 18-00z/2-8 pm for possible scattered thunderstorms that may lead to brief visibility reductions. Coming into the weekend, the cold front's progression will introduce cooler air and decrease the chance of storms. A tropical system may approach the Southeast coast early next week, with any possible impacts holding off until later next week or at the start of October, the forecast adds.
Marine conditions also warrant attention, with the Chesapeake Bay observing some southerly channeling, signaling potential for Small Craft Advisories. Thunderstorm chances will rise today and through the rest of the week, which may prompt Special Marine Warnings for stronger storms. On the waters, winds will continue from the south at moderate rates, though boaters should be cautious of sudden shifts in conditions during thunderstorms.
Finally, those in tidal regions should monitor the tides, as anomalies might result in minor flooding, particularly during the higher daily tide cycle in the afternoon and evening hours. The strongest onshore flow, leading to the highest anomalies, could potentially peak from Thursday into Friday.
