Marine Weather and Tide Forecast for Fallston, MD

NEAR TERM /UNTIL 6 AM MONDAY MORNING/
EVENING UPDATE...
Some clouds and isolated showers have developed around western Maryland and the eastern West Virginia panhandle this evening as the cold front approaches. A few flashes of lightning have also been noted with these cells. They have also continued further east than earlier CAMs suggested, though the latest HRRR now caps their eastward progression around the Blue Ridge. SPC continues to highlight a Marginal risk for severe thunderstorms in this area. Based on more recent CAMS, expect isolated showers with possible thunder from now until shortly after midnight for areas along and west of the Blue Ridge. Some weakening showers could make it further east, but would be less likely to have lightning and should quickly dissipate.

PREVIOUS DISCUSSION FOLLOWS...
The latest surface observations show the backdoor front has stayed north of the Mason-Dixon Line. An expanding warm sector is noted over the Mid-Atlantic, accompanied by increasing southerly warm advection. With only spotty clouds and continued surface heating, much of the area has seen temperatures rocket well into the 70s to low 80s. In particular, a spotty area of mid 80s can be expected across the Allegheny mountain valleys extending from Grant County up into western Allegany County.
Southerly winds will continue to be breezy at times, pushing into the 25 to 30 mph range at times.

Looking farther upstream, the pattern changing cold front looms back over central Ohio. Lagging behind is the parent upper trough which is currently spinning near the Upper Great Lakes.
Given the lack of alignment of the surface and features aloft, the focus for convection is somewhat nebulous. The Storm Prediction Center paints a Marginal risk for severe thunderstorms from I-81 westward. This is actually an eastward expansion from previous outlooks. 12Z HRRR ensemble paintball plots show some enhanced reflectivity racing from the Alleghenies toward I-81 during the early/mid evening hours.
Locally damaging wind gusts would be the primary threat given the higher LCLs and increasing downdraft CAPE values. Any convective threat decays for those farther east.

The cold front currently over the Ohio Valley is expected to cross the Allegheny Front late this evening before reaching the Chesapeake Bay by the middle of the overnight hours. This brings an abrupt wind shift to westerly which will become increasingly gusty in time. Low temperatures will be coolest west of I-81 with mainly 40s expected. Farther east, 50s to low 60s are more likely.

SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
The core of upper forcing with the trough pushes across the Mid-Atlantic region early Monday. This particular surge allows for the larger push in dew point falls as cooler/drier modified Canadian air works its way in from the northwest. Favorable upslope trajectories will carry a threat of rain showers along the Alleghenies. This is accompanied by mostly cloudy skies, gusty winds, and temperatures confined to the 40s. For downstream locations, a considerable cool down is also evident as high temperatures fall into the upper 50s to 60s (warmest south of I-66). This comes with a mixed bag of sun and clouds along with northwesterly wind gusts around 25 to 35 mph, locally up to 40 mph across the Allegheny mountain peaks. Winds begin to decrease in strength after nightfall with the loss of deep vertical mixing.

Enhanced cloud cover overnight should limit the true potential of nocturnal cooling. Low temperatures drop into the upper 30s to mid 40s, with widespread low/mid 30s over the mountains.
There should be enough wind to thwart off a widespread frost although the near freezing temperatures could cause a freeze in spots across the Alleghenies.

A reinforcing shortwave continues to trend deeper for Tuesday which has led to an uptick in precipitation chances. Not only will this bring a reinforcing shot of cold air, it also invigorates another round of shower activity along the Allegheny Front. Given the cooling temperatures, some of this will feature a mixture of rain and snow over the Allegheny ridges.
The current forecast does bring a couple tenths of an inch of snow over such locations. It remains to be seen if this will actually accumulate given marginal surface temperatures.
Elsewhere, scattered rain showers are advertised given the ample ascent underneath this strong trough. These likely weaken after dark as heating is lost. Tuesday's high temperatures hold steady in the mid/upper 50s, while the higher elevations can expect 40s to low 50s. With high pressure still back over the Mississippi Valley, it is not certain winds drop off enough to bring a widespread frost to those from U.S. 15 westward. The current forecast does drop lows into the mid 30s over much of that area, with low 30s over the mountains and I-81 corridor.

LONG TERM /WEDNESDAY THROUGH SUNDAY/
The main upper trough axis will pass overhead Wednesday morning, before moving off to our south and east later Wednesday afternoon into Wednesday night. At the surface, a broad area of high pressure will build eastward from the center of the country toward the Ohio Valley by Wednesday night. Northwesterly flow ahead of the approaching high will maintain below normal temperatures across the area on Wednesday. Upslope snow showers will continue along the Allegheny Front during the morning, before winding down during the afternoon hours. Further east, a mix of clouds and sun is expected.
High temperatures will range from the 30s and lower 40s in the mountains, to the 50s further east.

High pressure will continue to build eastward Wednesday night into Thursday, before becoming centered overhead Thursday night. The pressure gradient should weaken enough for many locations to decouple Wednesday night. Radiational cooling will allow temperatures to plummet into the 30s for most, with lower 40s in the urban centers. Frost and freeze headlines will likely be needed for much of the area. Sunny skies and light northerly winds are expected during the day Thursday. High temperatures will be in the upper 50s and lower 60s for most (upper 40s-lower 50s in the mountains).
Another night with ideal radiational cooling conditions is expected on Thursday night as the high builds overhead. Low temperatures will be in the 30s for most, and frost/freeze headlines will likely be needed once again.

High pressure will remain in the vicinity through Friday and Saturday as upper ridging builds in aloft. This will lead to continued sunny skies, light winds, and a warming trend in temperatures. Highs should be in the 60s on Friday (upper 50s/lower 60s mountains), and then upper 60s to lower 70s on Saturday (low-mid 60s mountains).

AVIATION /01Z MONDAY THROUGH FRIDAY/
While mainly VFR conditions are anticipated through Tuesday, the big story will be the gusty winds in response to a pronounced pattern change. Ahead of the cold front, expect a breezy southerly wind with gusts up to 20 to 25 knots through early this evening. This front tracks through overnight leading to a shift to westerly winds into the first half of Monday before turning more northwesterly. Gusts up to 25 to 30 knots are expected in this gusty post-frontal environment. Wind fields largely stay out of the west to northwest into Tuesday as well.
Afternoon gusts up to 20 knots are possible on Tuesday as a system aloft tracks through. This may also spark scattered showers over the area, although no restrictions are expected at this time.

VFR conditions and northwesterly winds are expected on Wednesday.
Light northerly winds and continued VFR conditions are expected on Thursday.

MARINE
Ahead of a strong cold front over the Ohio Valley, a breezy southerly wind has overspread the marine waters. As such, Small Craft Advisories are in place through tonight. This frontal boundary pushes across the waters early Monday morning leading to an abrupt shift to westerly winds. This gusty post-frontal environment will yield widespread gusts of 25 to 30 knots, potentially approaching gale force at times. However, model soundings and high-resolution model output are somewhat at odds at how widespread and frequent such gusts would be. For now, will maintain Small Craft Advisories through the day which will likely be extended into portions of Monday night.

Northwesterly wind gusts stay close to the 15 to 20 knot range through Tuesday, slightly toward that higher range later in the day. Small Craft Advisories may be needed over portions of the waters during this period.

Northwesterly winds may reach low-end SCA levels on Wednesday. Light northerly winds are expected over the waters on Thursday.

TIDES/COASTAL FLOODING
Strengthening south winds may result in a surge into Action Stage along sensitive shoreline later today. No coastal flooding is explicitly forecast at this time, although guidance is closest to minor flood stage at Annapolis. The threat ends behind a cold front tonight.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ530>543.