Marine Weather and Tide Forecast for Stafford Courthouse, VA

NEAR TERM /THROUGH TONIGHT/
After a chilly start to the morning temperatures are quickly rising - now in the 50s to low 60s as of 930AM. Expect high temperatures to overshoot most of the model guidance due to full sunshine with late April solar insolation angles. Temperatures reach the mid/upper 70s with low 80s across the Allegheny mountain valleys. High pressure overhead keeps winds light and variable through the afternoon, then shifting to south as the high moves offshore this evening.

A dry air mass continues into the night, accompanied by some passing high clouds. The warm advection regime does raise overnight temperatures quite a bit. Relative to current conditions, expected lows will be around 10 to 15 degrees warmer. That is, widespread upper 40s to low 50s.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
Mid/upper level heights will continue to rise on Tuesday with 500-mb 24 hour changes from 576 dm to 582 dm (6 dm). The northern extension of this ridge axis is expected to be trimmed down by a progressive northern stream shortwave. The stronger corridor of jet energy is confined to areas north of the Mason- Dixon Line. A bulk of the stronger buoyancy is located back over the Ohio Valley into upstate New York. Most high-resolution models favor an eastward propagating mesoscale-convective system (MCS) tracking toward Garrett County by the early evening hours. It remains to be seen how intact the system will be once it reaches far western Maryland. The overall best shot for any thunderstorms would be west of the Blue Ridge and Catoctin Mountains. The latest Storm Prediction Center outlook places a Marginal risk for severe thunderstorms across western Maryland down into portions of the eastern West Virginia panhandle.
Damaging wind gusts are the primary threat through the evening.
Eventually this should transition into a sub-severe event into the rest of the evening and night while progressing toward the I-95 corridor.

The other side of this building of heights will be the marked warmup. In response, a surface warm front sweeps through the area midday. Forecast highs rise into the upper 70s to mid 80s which is around 10 to 15 degrees above climatology. While southerly winds will raise dew points into the 50s, conditions should still not feel very humid at this point. Nighttime temperatures stay very mild given continued passing showers and ample cloud cover. Low temperatures in the low/mid 60s will be commonplace, with mid/upper 50s across mountain locales.

A cold front to the west will near the region on Wednesday morning. Forecast guidance still are at odds of where this boundary sets up. Dew points in the 40s will be more commonplace north of this front, while 60s dew points can be found off to the south. This frontal zone remains a focus for shower activity, with thunderstorms possible within the more unstable warm sector. Overall temperatures remain mild as high temperatures should again be in the upper 70s to mid 80s. The parent boundary gradually sags southward in time with high pressure building to its north. A shift to northeast to easterly winds will help lower nighttime temperatures a bit. Lows are forecast to be in the mid 50s to low 60s.

LONG TERM /THURSDAY THROUGH SUNDAY/
Ridging overhead will quickly breakdown and move offshore Thursday as a potent lead shortwave rounding the base of a central CONUS trough approaches from the OH Valley. At the surface, a stalled front just to the south will lift northward as a warm front. Modest lapse rates aloft atop increasing low-level moisture and surface temps rising into the 80s could yield moderate instability heading into the afternoon ahead of the approaching shortwave. As the wave moves overhead and the warm front continues to lift north, shower and thunderstorm activity may break out across much of the region.
Mid/upper-level flow attendant to the approaching wave will increase resulting in favorable shear profiles for organized thunderstorms.
Cloud cover associated with the lingering warm front and leftover from upstream convection in prior days could hinder heating and instability somewhat, but the potential exists for at least a few strong to severe thunderstorms Thursday afternoon and evening.

The parent trough will swing eastward toward the Mid-Atlantic Friday. Deep layer flow will continue to increase. Guidance has a bit of spread on low-level wind direction, possibly due to a lingering surface trough near I-95 in the wake of the prior day's wave that would result in more westerly surface winds. This would result in lower CAPE values, but mesoscale features of this nature are difficult to pin down several days in advance. Synoptically speaking, the approach of a seasonably deep upper trough and strong surface cold front after several days of above normal temperatures suggests a continued threat for strong to severe thunderstorms, predicated on exact timing and evolution of other mesoscale factors listed above.

Temperatures take a tumble heading into next weekend as high pressure of Canadian origin builds in. Prior to the high pressure center moving overhead, blustery northwest winds are likely for the day Saturday.

AVIATION /14Z MONDAY THROUGH FRIDAY/
VFR conditions are expected through at least Tuesday afternoon given the initial influence of Canadian high pressure.

Light/variable winds in place through this afternoon before shifting to southerly later this evening and night. Return flow increases into Tuesday with some threat for showers and thunderstorms, especially west of the Blue Ridge. Some restrictions are possible Tuesday evening at KMRB as an upstream MCS tracks toward western Maryland. Residual showers push toward the east which may impact downstream terminals.

A cold front slips southward through the area on Wednesday.
Periods of sub-VFR conditions are possible as showers track through. Winds shift to northeast to easterly in the wake for the remainder of Wednesday.

A warm front looks to lift northward across the area Thursday, followed by a strong cold front Friday into Friday night. Bouts of showers and thunderstorms with associated sub-VFR conditions are possible, though VFR is expected to prevail. Winds will start SE Thursday morning, pivot around to the S and SW late Thursday into Friday, then become NW by Saturday morning.

MARINE
Canadian high pressure will maintain lighter winds for much of today, bringing favorable marine conditions to all the waters.

As this ridge exits the coast, return flow ensues with southerly channeling effects possible late tonight. The flow should continue to increase through the day on Tuesday. Small Craft Advisories will likely be needed during this period of time, continuing into Tuesday evening. Any thunderstorm activity during the evening/night hours on Tuesday should remain west of the waters.

A cold front gradually moves through the area early Wednesday.
Additional showers are possible as the wind shifts to northeasterly and stays below advisory levels.

Southerly winds may increase Thursday as a warm front lifts north, and could result in SCA conditions Thursday afternoon and night. The wind will likely remain elevated out of the southwest Friday ahead of a strong cold front, before becoming northwest by Saturday. SCA conditions will remain possible during this time. Periods of showers and thunderstorms are also possible as the frontal system crosses, especially during the afternoon and evening hours each day.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.