


Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
965 FXUS61 KLWX 160750 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 350 AM EDT Mon Jun 16 2025 .SYNOPSIS... Cool, damp, and dreary conditions kickoff the new workweek as a stalled front remains nearby. A warm front will lift into the area Tuesday and Wednesday allowing temperatures to rebound while keeping a daily chance for showers and thunderstorms. Severe thunderstorms are possible Thursday into Friday as a strong cold front crosses the region. High pressure returns this weekend with hot and dry conditions expected. && .NEAR TERM /THROUGH TONIGHT/... he CAD wedge continues to remain over the region today with strong inversion this morning. This has led to a continuation of low clouds, fog, drizzle, and passing showers across much of the region. Outside of the low clouds, showers, and mist; the area sits in a bit of lull (at least from heavier precipitation) within a much more stable maritime airmass. Shortwave low pressure from last night into early this morning continues to slowly exit east while the stalled front remains draped over the Alleghenies southward into southwest VA and northeast NC. Meanwhile, another ripple of shortwave energy is spinning back across southern Ohio, western WV, and eastern KY. This feature along with the dissipating stalled front to the south will be the catalyst once again for showers and perhaps a few thunderstorms across portions of the region later this afternoon and into the evening hours. Highest coverage for shower and thunderstorm activity today looks to be once again across the Alleghenies back into southwest and south-central VA. A Flood Watch has been issued for areas along and west of the US-220 corridor (i.e Garrett Co. MD south toward Pendleton Co. WV/Highland Co. VA) from noon today through midnight tonight. These locations received anywhere between 0.50-2" of rain yesterday which will further aid in flooding concerns today. 00z CAMS/synoptic guidance continues to hit this area hard for widespread convection later this afternoon. Convective development once again appears to be midday through roughly 7-9pm this evening. MUCAPE values will hover between 500-800 j/kg with 0-6km shear values around 30 kts. PWATS will remain elevated between 1.2 and 1.8 inches. Warm rain processes will once again be the theme with more stratiform compared to convective elements due in part to the CAD wedge overhead. Shower and drizzle activity will slowly decrease later this morning into midday. Cloud cover will prevail limiting highs temperatures to the upper 60s and low 70s areawide. Locations west of the Allegheny Front and south of I-64 may filter a break of sunshine or two yielding highs in the mid to upper 70s. The wedge will still be hard to scour as the front to the south dissipates and eventually begins a slow jog back to the north as warm frontal boundary heading into Tuesday morning. This means more of the same with low clouds, fog, drizzle, and lingering showers at times during the overnight and early morning period. Lows tonight will fall back into the low to mid 60s. Values closer to 70 degrees can be found in the Baltimore/DC urban centers, near the bay, and south of the I-64 corridor. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... The stalled surface boundary that will have lingered over the area for several days will finally start to dissipate and lift north of the area as a warm front Tuesday into Wednesday. Meanwhile, a subtle upper level trough will approach from the Ohio Valley. Showers and thunderstorms are expected to form during the afternoon hours within a very humid airmass (surface dewpoints around 70). The risk for severe weather is low, but not 0 with the Storm Prediction Center highlighting a Marginal Risk (Level 1 out 5) over portions of the Alleghenies and Shenandoah Valley/central Piedmont region. Damaging winds look to be the main threat with storms along with localized flash flooding. Storms should be fairly progressive, but given the antecedent conditions and moist atmosphere at play localized instances of flash flooding cannot be ruled out. CAPE values will approach 2000 j/kg with 0-6 km shear values 35 to 45 kts. High temperatures on Tuesday are expected to be reach into the upper 70s and lower to mid 80s for most as sunshine returns. Lows Tuesday night will fall back into the upper 60s and low 70s. FOg will be possible during the overnight hours given the very moist airmass overhead. More of the same can be expected Wednesday as the warm front lifts further north of the area. This will allow hotter temperatures to move in along with slightly drier conditions under the influence of west to southwest downsloping flow. Current CAMS and synoptic guidance still hint on the threat of a few showers and thunderstorms during the afternoon and evening hours Wednesday. This is due largely in part to a shortwave trough ejecting east of the Ohio River Valley. Highest probability of severe thunderstorms looks to be west of the Alleghenies where the shortwave trough will reside. Elsewhere, pop showers and thunderstorms are likely given the hot and humid airmass in place. Highs Wednesday will push into the mid to upper 80s and low 90s outside the mountains. The lead shortwave trough works east Wednesday night into THursday as the cold front approaches form the Ohio River Valley. Convection over the mountains will work east as well before slowly dissipating given the lack of instability during the overnight hours. Lows Wednesday night will fall back into the low to mid 70s. && .LONG TERM /THURSDAY THROUGH SUNDAY/... High pressure strengthens offshore moving into the middle of the week, leading to south to southwesterly low-level flow and increasing heat and humidity locally. Temperatures should reach into the 90s on both Wednesday and Thursday. When combined with dewpoints in the lower 70s, heat indices may approach 100 on Thursday. Thunderstorms could have decent coverage on Thursday as an upper trough tracks off to our north across the Great Lakes, with its associated cold front approaching from the west. Current model guidance suggests that ample instability and shear may be present on Thursday, so some storms may be on the stronger side. SPC has the area highlighted with a D4 outlook, so definitely something to keep an eye on. Upper troughing is expected to dig in from the Great Lakes on Friday. Cooler and drier conditions are expected locally in the wake of the system`s cold front Friday into Saturday before warming up on Sunday. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... IFR conditions look to continue through mid-morning as a result of low clouds, passing showers, and patchy drizzle. OVC CIGS will continue to hover between 500-1000 feet, with pockets of sub 500 feet CIGS amongst the terminals through at least 15z/11am this morning. CIGS may lift a bit this afternoon and evening as additional shower activity works through. Outside of the light to moderate shower/drizzle activity in the corridor this morning expect the highest concentration of showers and perhaps a few thunderstorms this afternoon to remain west of KMRB and KCHO. Convection will pop over the mountains between 16-19z/12-3pm with a few spotty showers further east due largely in part to onshore maritime flow. Shower activity will filter back into the corridor late in the afternoon and through the evening hours with the next wave of shortwave energy pivoting through. Once again coverage will be scattered so tried to use PROB30 groups to highlight this. Low clouds, fog, and drizzle set up again overnight leading to additional IFR CIGS/vsbys and even some brief periods of LIFR west of the corridor terminals. Winds will remain out of the east and northeast today at less than 15 kts. Sub-VFR conditions may be possible Tuesday morning, but improvement back to prevailing VFR conditions is expected Tuesday afternoon through Wednesday as a warm front lifts through the region. This will finally scour out the low clouds. Temporary drops to sub-VFR conditions may be possible in thunderstorms both Tuesday and Wednesday afternoon, especially at terminals along and west of the Blue Ridge. Prevailing VFR conditions are expected Thursday. Temporary drops to sub-VFR conditions may be possible in thunderstorms especially Thursday afternoon and evening. && .MARINE... A stalled front will remain south of the waters through this evening. Easterly winds around 10 knots, and likely remain sub-SCA through the start of the week. Occasional gusts to around 20 knots are possible at times. Low clouds and some marine fog is possible this morning and again tonight given the moist airmass in place. Less shower and thunderstorm activity is also expected today given the proximity of the boundary south of the region. A warm front will lift back across the waters Tuesday into Wednesday. Sub-SCA level southerly winds are expected over the waters on both Tuesday and Wednesday. An SMW or two cannot be ruled out with scattered showers and thunderstorms during the afternoon and evening hours. SMWs are possible given thermodynamic and kinematic environment for Thursday in any thunderstorm. SCA conditions likely return with cold frontal passage Thursday into Friday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Flood Watch from noon EDT today through this evening for MDZ501-509-510. VA...Flood Watch from noon EDT today through this evening for VAZ503-504. WV...Flood Watch from noon EDT today through this evening for WVZ501>503-505-506. MARINE...None. && $$ SYNOPSIS...EST NEAR TERM...EST SHORT TERM...EST LONG TERM...CPB AVIATION...KRR/EST MARINE...KRR/EST