Marine Weather and Tide Forecast for Edgewood, MD

KEY MESSAGES
- 1) Near record warmth and mainly dry conditions continue through Wednesday.

- 2) A strong cold front moves through on Friday, bringing strong winds, the potential for thunderstorms, and then cold conditions in its wake for this weekend.

DISCUSSION
KEY MESSAGE 1...Near record warmth and mainly dry conditions continue through Wednesday.

Weak high pressure nearby and mid-level ridging will continue to dominate the forecast heading into Wednesday. The high itself will slide offshore later today allowing the mid-level ridge to buckle heading into Wednesday. Meanwhile, a series of shortwave disturbances will quickly slide from west to east across northern portions of the forecast region as a cold front drops south from the Great Lakes and Ohio River Valley. This front will touch off showers and a few thunderstorms late Wednesday afternoon and evening, mainly in areas along and north of I-66/US-50 and US-48. A Marginal Risk (Level 1 out of 5) for severe weather remains in place for portions of western MD, eastern WV, and the VA Highlands Wednesday afternoon where better instability/shear will reside. Thunderstorm coverage overall will be isolated to scattered with damaging winds as the primary concern (especially west of the Blue Ridge (between 3-8pm)).
Most locations will remain dry through Wednesday afternoon given the timing of the front and residual dry air to punch through as the mid- level ridge slowly buckles.

Before the front arrives, expect near record warmth this afternoon and again Wednesday. Highs today will reach into the low to mid 80s (mid 70s mountains). Lows tonight will fall back into the upper 50s and mid 60s. Highs Wednesday will be much warmer in the mid to upper 80s and potentially low 90s for areas south and east of DC (mid 70s mountains).

Cooler conditions return briefly Thursday as more of a wedge like pattern settles in. This is due to a large surface high pressure system anchored over southern Ontario wedging south along the eastern face of the Appalachians. Expect cloudy conditions to prevail along with passing showers, especially across the central and southern 2/3rds of the forecast region. Highs will return closer to normal with most locations in the mid to upper 60s. The CAD will quickly erode Thursday night into Friday as winds switch back to the south/southwest ahead of the next front heading into the weekend.

KEY MESSAGE 2...A strong cold front moves through on Friday, bringing strong winds, the potential for thunderstorms, and then cold conditions in its wake for this weekend.

A potent shortwave trough will approach from the Great Lakes on Friday. A strong area of low pressure will form just downstream of this trough and track northeastward into the St. Lawrence Valley over the course of the day. Southerly flow ahead of the system will advect an unseasonably warm and humid airmass northward into the area, with temperatures forecast to climb into the 80s and dewpoints reaching into the 60s. The system's cold front will move through the area Friday afternoon into Friday evening. The front will move into an environment with around 500-1000 J/kg of instability, so a line of thunderstorms may ultimately form along the front. If thunderstorms were to form, they may be capable of producing damaging winds, given the strong winds that will be in place just above the surface (around 40-45 knots at 850 hPa). Regardless of whether storms form or not, strong northwesterly winds are expected behind the system's cold front late Friday through Friday night and into early Saturday morning. Frequent gusts of 30-40 knots appear likely across the area in northwesterly flow, and some locations may even see some gusts above 40 knots. The Alleghenies and Blue Ridge appear to be the most likely locations to reach Wind Advisory criteria of 40 knots.

Strong cold advection will also accompany the gusty winds, with 850 hPa temperatures plunging from in excess of 15C Friday morning to below 0C by daybreak Saturday. Some upslope rain showers appear likely Friday night in the Alleghenies, and some snowflakes may even mix in by late Friday night. Air temperatures are forecast to dip into the 40s for most Friday night, with 30s in the mountains. By daybreak Saturday, wind chills will be in the 30s at lower elevations, and 20s in the mountains. Northwesterly winds will gradually decrease through the day Saturday, with temperatures forecast to climb into the 50s (40s mountains). High pressure will build overhead Saturday night, resulting in clear skies and calm winds within what will already be a cool background environment.
This will be a near ideal situation for radiational cooling. With dewpoints forecast to be in the 20s and lower 30s, it appears as though a freeze may be possible for many locations, especially to the west of the Blue Ridge. At least frost appears likely just about everywhere, and freezing temperatures could encompass the entire area outside of the immediate downtown areas in DC/Baltimore if cooler solutions were to verify. Frost/Freeze headlines will likely eventually be needed for much of the forecast area.

Quiet weather conditions and a gradual warming trend in temperatures are expected for Sunday and Monday as high pressure moves offshore.
High on Sunday and Monday will generally be in the 60s (50s mountains), with overnight lows in the 30s and 40s.

AVIATION /18Z TUESDAY THROUGH SUNDAY/
VFR conditions expected this afternoon through Wednesday afternoon as weak high pressure resides nearby. A front will drop into the area from the north late Wednesday afternoon and evening bringing with it scattered showers and thunderstorms. This will lead to brief sub-VFR reductions between 20-03z/4-11pm. Overall confidence for thunderstorm activity over the I-95 corridor terminals is less than 25 percent with higher thunderstorm probabilities of 25 percent or greater mainly west of MRB. The front drops south of the region Thursday before stalling in the vicinity of southeast and southwest VA. This will put us in more of a wedge-like pattern with on and off showers and widespread sub-VFR (cigs) conditions at most of the terminals. Winds will remain out of the south today at 5 to 10 kts with occasional gusts up to 20 kts. South winds continue tonight into Wednesday at less than 10 kts. Did mention LLWS along and west of MRB and SHD tonight 2KFT AGL at 35 kts. Winds will switch to the north and northeast Thursday at less than 15 kts in the wake of the frontal boundary.

VFR conditions and gusty south to southwesterly winds are expected Friday morning. A strong cold front will move through Friday afternoon. A line of thunderstorms could potentially accompany the front, leading to a brief period of sub-VFR conditions. Strong northwesterly winds are expected behind the front late Friday afternoon through Saturday morning, with gusts of 30-40 knots possible at times. Continued VFR conditions are expected on Saturday, with winds remaining out of the northwest, but gradually decreasing in magnitude throughout the day.

MARINE
South winds around 10 to 15 knots are expected today across the waters. Southerly channeling effects could bring gusts close to SCA levels (around 20 knots), but this likely won't be for a long enough period to require a Small Craft Advisory. Instead, Marine Weather Statements are more likely to be issued for small crafts to exercise caution.

Winds diminish tonight into Wednesday, with generally sub-SCA conditions. A front moves south across the waters Thursday morning, and this is likely to bring SCA conditions with gusts around 20 knots for several hours. Winds do quickly diminish Thursday afternoon.

SCA level winds appear likely in south to southwesterly flow Friday morning. A strong cold front will move through Friday afternoon into Friday evening. A brief line of thunderstorms may accompany the front. Winds shift to northwesterly behind the front, and Gale conditions appear likely along/behind the front Friday evening into early Saturday morning. Winds will remain northwesterly on Saturday, but gradually decrease in magnitude through the day.

TIDES/COASTAL FLOODING
South winds on Wednesday could result in elevated water levels at sensitive locations along the Chesapeake Bay. This could result in several stations reaching Action Stage, with Annapolis and Havre de Grace forecast to be closer to minor tidal flooding during the Wednesday morning high tide. A surge of offshore (north)
winds Thursday morning will bring water levels back down.

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