FXUS61 KLWX 220802 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 402 AM EDT Sat Aug 22 2026 .WHAT HAS CHANGED... Update on the current showers developing over southern MD and the VA Piedmont. Flooding threat remains limited, but will need to be monitored closely as the axis of heavier rain sets up throughout the morning. Also updated aviation and marine discussions substantially to add more details on today's setup. && .KEY MESSAGES... - 1) Showers and thunderstorms today with the potential for heavy rainfall and isolated instances of flash flooding. - 2) Dry conditions anticipated Sunday through early next week. - 3) Warmer and more humid conditions return mid-week, with thunderstorm chances returning by Thursday. && .DISCUSSION... KEY MESSAGE 1...Showers and thunderstorms today with the potential for heavy rainfall and isolated instances of flash flooding. Latest surface analysis still depicts a stalled frontal boundary off to our south and east. Satellite imagery depicts an influx of moisture into the region east of an approaching upper trough axis. We are starting to see some heavier showers develop in the right entrance region of a 90 knot upper-level jet. Low pressure is developing over the Carolina, but remains very loosely developed at this stage. At any rate, all of these features are expected to evolve throughout the day, giving a continuous threat for showers and thunderstorms through the afternoon hours. The latest SPC mesoanalysis is starting to hone in on an area generally southeast of the I-95 corridor. PWATs in this region remain in the 1.6-1.8 inch range, with a decent overlap of low- level moisture convergence and PPP. Current forecast calls for 1-2" somewhere along/southeast of I-95, but could see some locally higher amounts. As it stands right now, the region of concern should fall just southeast of the metro areas. Sandy soils and antecedent low soil moisture in this region should mitigate the flooding threat. However, the one exception will be if the heaviest axis either shifts north into St. Marys county, where recent heavy rains leave that area slightly more susceptible to flooding. Additionally, if the axis does shift north into the metros, flash flooding could become an issue. No flood watch at this time, as confidence remains higher that the highest rain totals will fall in less susceptible areas. If that changes, one may be considered later this morning. During the late morning and early afternoon hours there could be a lull, but there remains a chance for pop-up showers and storms pretty much anywhere during this period. By evening, another round of showers and thunderstorms will approach the Appalachian Mountains and may make to areas east of the Blue Ridge Mountains overnight into early Sunday. Severe threat is low with these, as they will be running into stable surface air. However, they could bring some heavy rainfall and thunder. Some fog may then develop in the valleys and VA Piedmont, but it will have to do so prior to the arrival of the front. By Sunday morning the cold front will be crossing the area with dry air advection ensuing in strengthening NW winds. However, there could still be enough moisture and lift to spark a few showers, but overall drying conditions are expected throughout the day. KEY MESSAGE 2...Dry conditions anticipated Sunday through early next week. Dewpoints drop sharply in the wake of the cold front Monday as dry air moves into the region from the Midwest. Surface high pressure will begin to build over the Appalachians and track east over the next couple of days, with conditions feeling briefly fall-like as temperatures range slightly below average for August. Overnight lows range largely in the 50s throughout the region by Tuesday, and sub-60F dewpoints could persist until midweek. KEY MESSAGE 3...Warmer and more humid conditions return mid- week, with thunderstorm chances returning by Thursday. As the week continues, a broad upper-level trough will begin to form over the Great Lakes and track towards the Mid-Atlantic by Thursday. As the associated surface low approaches the region, moist air from the south will flow into the area, bringing back an increase in humidity & temperatures back to late-August normals. As this low tracks through, expect shower & thunderstorm chances to increase as the associated cold front tracks offshore by the end of the week. Medium-range severe indices still maintain a low-end non-zero chance for stronger convection as this front moves through. Temperatures rise back into the upper 80s by Thursday. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... Low pressure tracking along a stalled boundary to our southeast will push showers and some embedded storms into the region later this morning. Still lots of uncertainty with just how much rain falls and how intense any showers will be that reach the terminals. Low clouds will also be an issue, which makes restrictions likely. Though, if the showers and up being less intense, it is possible that conditions remain low-end MVFR rather than dropping to IFR. Latest TAFs reflect some uncertainty there, with areas further east a bit more likely than those to the west. Another low pressure system over the Great Lakes region will push a cold front through the region later tonight. This will bring another line of shower and storms along with it, persisting through the early overnight hours. This could bring another period of restrictions. In the wake of the rain, fog is expected to develop at CHO and probably MRB as well Sunday morning. It is possible it could creep into IAD as well. Predominantly VFR conditions are anticipated across terminals Sunday through Wednesday. Winds on Sunday through Tuesday remain out of the WNW to NW, gusting up to 20 knots during the afternoon hours (except CHO which will be 5 to 8 knots lower). Beginning Wednesday afternoon, winds shift out of the south, but should be a bit weaker. Additionally, a few showers and thunderstorms become possible ahead of an approaching cold front that could bring temporarily reduced conditions into the evening and perhaps overnight hours. && .MARINE... Easterly winds expected today around 5 to 10 knots with gusts up to 15 knots as low pressure slides by to our southeast. SCA conditions are not expected, however any heavier showers or storms could bring down gusts around 20 to 25 knots at times throughout the day. These would likely come in short bursts, and should be few and far between. Another line of showers and storms moves in late tonight, but again should not bring any substantial wind gusts as we will be stable. Winds turn out of the WNW Sunday through Tuesday, and should remain sub-SCA throughout that period. A few gusts near 18 knots are possible, especially further north, but not seeing a prolonged period enough to warrant an SCA at this time. Winds shift southerly by Wednesday, with winds gusting above SCA thresholds later that evening in a classic southerly channeling event ahead of an approaching cold front. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ DISCUSSION...CJL/SRT AVIATION...CJL/SRT MARINE...CJL/SRT