Marine Weather and Tide Forecast for Potomac Heights, MD

NEAR TERM /THROUGH TONIGHT/
It appears that the dew point gradient associated with the backdoor front stretches across central Pennsylvania to southern New Jersey and likely won't make much more southern progress.
Low pressure is entering Indiana, with convection along the warm front along northern Ohio. It does appear radar returns farther south (approaching western Maryland) are from a mid level cloud deck and not reaching the ground.

Most of the day does appear dry with only some patchy mid and high level clouds. S-SW flow will strengthen this afternoon, helping boost temperatures well above normal. Most areas will reach the lower to mid 80s. Wind gusts should generally be in the 20-35 mph range. While some higher gusts could occur, especially in the mountains, given the winds depicted in the boundary layer, am thinking the typically inefficient mixing in warm advection regimes reduces the risk for wind advisory criteria.

Attention then turns to the convective threat. Height falls and the approaching cold front will begin to approach from the west after 5 PM. Showers and a few thunderstorms will be most probable along the Alleghenies, then generally break apart farther to the east due to displaced mid level forcing, unfavorable diurnal timing, and WSW flow aloft. With that said, some modest instability of 500-1000 J/kg will be present (especially west of I-81) overlaid with strong winds aloft.
Therefore, a localized instance of strong to severe winds can't be ruled out, especially if activity can organize to our west.
However, thermodynamic profiles place doubt in robust updrafts, especially since the best forcing will be in the low levels.
Most guidance has cut back on precipitation east of the mountains, with the highest chance for a shower or storm still appearing to be west of I-81 and north of I-66/US-50.

The cold front will push eastward across the area tonight, with cooling gradually occurring from west to east. Locations east of I-95 likely stay in the 60s while the higher elevations fall into the 40s. Some upslope rain showers may linger. The surge of higher postfrontal winds approaches toward dawn. By this time, upslope saturation has taken place, casting doubt on the need for any wind advisories along the terrain.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
A secondary front will cross the area Monday, with winds potentially gusting 25-40 mph at times. Clouds will also be more common, especially closer to the mountains. Light upslope precipitation will be possible at times, especially in the afternoon. Snow will be possible on the higher peaks as 850 mb temperatures approach 0C. Cold advection will limit temperature rises, with most areas staying in the 60s.

The longwave trough aloft will continue to develop over the eastern US, with a shortwave potentially deepening the trough axis toward the area on Tuesday. Only some light upslope rain and snow showers are expected Monday night, and winds will likely lighten substantially overnight. The best forcing arrives on Tuesday, with mostly cloudy skies and potential for at least a few showers across much of the forecast area. The Alleghenies may see some brief heavier snow showers given the instability, but air temperatures will be well above freezing on all but the highest peaks. Cloud cover and continued cooling of the airmass will keep highs in the 50s. The threat for precipitation will end east of the Alleghenies by evening, but some light upslope rain and snow showers will continue overnight. Lingering wind should prevent temperatures from crashing too far, but near or subfreezing temperatures are most likely from the central Shenandoah Valley west into the highlands. Otherwise mid 30s to mid 40s are forecast.

LONG TERM /WEDNESDAY THROUGH SATURDAY/
An elongated positively-tilted upper trough of low pressure and energy within it will pivot across the region Wednesday. This synoptic setup, along with a light to moderate west-northwest to northwest wind at the surface, will enable any rain or snow showers to linger in parts of the northern Appalachians. Most of this activity would occur Wednesday morning to around midday. Elsewhere will be dry and colder. Once the trough and energy move to the east of our region later in the day Wednesday, any rain or snow showers will cease in the mountains. High temperatures Wednesday will only reach the lower to middle 50s. In the mountains, where cloud and light precipitation will be slow to exit, highs will only reach the upper 30s to lower 40s.

High pressure will gradually build into the region Wednesday night through Saturday. Dry conditions and chilly temperatures will exist each day. There is the possibility of areas of frost Wednesday night and again Thursday night. Lows Wednesday night upper 20s to middle 30s west of the Blue Ridge, while upper 30s to near 40 to the east.
High and low temperatures will remain chilly as well Thursday with much of the same values. A slight modification in temperatures for Friday and Saturday, but still a few degrees below average.

AVIATION /08Z SUNDAY THROUGH THURSDAY/
VFR conditions will largely rule the next few days despite a frontal passage. Low pressure will pass north of the area today.
South to southwesterly winds increase this afternoon to early evening with gusts up to 20 to 25 knots. A fairly strong cold front pushes through tonight, shifting winds to the west. It is looking increasingly unlikely any precipitation reaches the TAF sites. Monday's wind gusts could push up to around 30 knots at times. Expect these to winds to diminish in strength after dark. Some MVFR ceilings could approach MRB Monday night.

An upper level disturbance may bring a stray shower on Tuesday.
If this system trends stronger, a period of sub-VFR conditions could occur. NW winds gust up to 20 kt.

VFR conditions Wednesday through Thursday night. Winds northwest 10 to 15 knots gusts 20 knots Wednesday. Winds northwest 5 to 10 knots gusts 15 knots Thursday.

MARINE
Ahead of low pressure over the Great Lakes, southerly winds increase today with 20 to 25 knot gusts across all waters by afternoon. Some gusts around 30 kt are possible tonight, but think winds should remain below gale force. Expect an abrupt wind shift to west late tonight. As a surge of stronger winds arrives Monday, there are indications that some portions of the Chesapeake Bay could see near gale force winds. However, it appears such potential is brief at best, so have extended the SCA through the day on Monday. Residual gusts persist into the night which will require additional Small Craft Advisories, although a weakening trend should occur toward Tuesday morning.

During the daytime Tuesday, SCAs may be needed, but winds look a little more marginal. Another surge of northwest winds will occur Tuesday night, strongest along the bay.

Small craft advisories likely Wednesday and Wednesday evening. Winds northwest 10 to 15 knots gusts 20 knots or higher. No marine hazards expected Thursday and Thursday night. Winds northwest around 10 knots few gusts 15 knots.

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...Small Craft Advisory from noon today to 6 PM EDT Monday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from noon today to 6 PM EDT Monday for ANZ530>532-535-536-538>540-542.
Small Craft Advisory until 6 PM EDT Monday for ANZ533-534-537- 541-543.