Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
944 FXUS61 KLWX 250759 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 359 AM EDT Sat May 25 2024 .SYNOPSIS...
-- Changed Discussion --
A frontal boundary will dissipate near the Mason-Dixon Line today. Another boundary settles to the north and remains there through the holiday weekend. Eventually, a much stronger cold front pushes through the region Monday into Monday night. A secondary cold front moves in by mid-week before high pressure builds in late next week.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Convective development today is likely to be delayed until the late afternoon or early evening and will probably wait until a shortwave trough approaches during the evening. One or two small cluster of thunderstorms may develop across eastern OH, western PA, and northern WV in the late afternoon and move across the Appalachian region and northern half of the CWA this evening before dissipating overnight.
-- End Changed Discussion --
&& .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
-- Changed Discussion --
Model guidance indicate significant height rises through the day Sunday ahead of deepening trough over the western Great Lks. While this should tend to suppress convective development, air mass is expected to become moderately unstable by afternoon with MUCAPE of ~1000 J/kg. Scattered thunderstorm development is possible along a weak pressure trof. Some remnant MCS from the OH Valley may also make it into the area during the overnight hours Sunday night. Memorial Day...Some remnant or decaying convection is possible early in the morning. By afternoon, height falls and strengthening sfc convergence along a deepening sfc trof is expected to result in convective initiation with all modes of severe weather possible before convection tries to evolve into an increasingly organized line. This appears to be the most significant severe wx event so far this convective season. Despite expected relatively fast storm motions, isolated flash flooding is also possible due to multiple rounds of convection. Storms are likely to exit the area by 02Z Tue if not a little sooner than that.
-- End Changed Discussion --
&& .LONG TERM /MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
CAPE decreases significantly behind the front Monday, though a passing SW trough could bring additional rain showers Tuesday into Wednesday. Does not look like a washout either day with weak sfc high pressure underneath the upper level system. Behind this wave, dew points will fall into 40s come next Thursday with highs in the upper 60s to low 70s. This may be the least humid day until September across the area. Likely remaining dry into Friday before the next system brings the potential for rain showers or thunderstorms next Saturday.
-- End Changed Discussion --
&& .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Best chance for t-storms today is at MRB. Widespread showers and thunderstorms expected on Memorial Day with severe thunderstorms likely. Prevailing VFR conditions are likely Tuesday into Wednesday, though a passing shower is possible. Winds will become northwesterly at about 10 kts.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Winds should remain below SCA until Sun night. Isolated t-storms are possible this evening. Widespread showers and thunderstorms expected on Memorial Day, some of which are likely to be severe and require SMWs. SCAs are likely Sunday night through Monday night. A passing shower is possible over the waters Tuesday into Wednesday. Winds will be prevailing out of the NW about 10 kts, with gusts up to 15-20 kts during the afternoon hours.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING... Water levels are expected to gradually rise into the weekend given south to southeasterly warm advection. Many tidal sites see their higher of the two high tides reach Action stage. Further increases are likely into Monday/Memorial Day which could lead to some coastal flooding. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...CPB AVIATION...LFR/CPB MARINE...LFR/CPB TIDES/COASTAL FLOODING...LFR