Marine Weather and Tide Forecast for Silver Spring, MD

NEAR TERM /THROUGH TONIGHT/
As of 08Z/3 AM, the local WSR-88D radar imagery over the region shows a narrow band of light to locally moderate rainfall pushing east of the I-95 corridor. Thus far, overall rain totals have been higher than expected, generally averaging between 0.10 to 0.25 inches. This is all in response to an approaching cold front currently pushing across the Allegheny Front. Based on observational data, this boundary consists of minimal thermal gradients while mainly being driven by a wind shift. Nighttime GOES-19 imagery shows thickening stratus behind this front while extending from central West Virginia back into the Ohio Valley. However, all precipitation largely comes to an end as the initial activity sweeps east of I-95.

Overall temperatures are fairly uniform with readings mainly in the 50s. While dry advection should help erode some of the cloud cover, the approaching stratus shield could favor some morning low clouds over the area.

Expect daytime heating to unfold rather quickly aided by a west-northwesterly downsloping flow. With forecast 850-mb temperatures around 6 to 8C, a well mixed boundary layer should support dry adiabatic mixing down to the surface. This would favor high temperatures in the upper 60s to low 70s, especially south of I-70 and across the Shenandoah Valley. Mid 60s will be more commonplace closer to the Mason-Dixon Line, while 50s can be expected over mountain locations. Mostly sunny skies are likely before clouds increase late in the day as an upstream shortwave digs toward the Tennessee Valley.

A secondary cold front approaches from the west tonight before lifting north of the Mason-Dixon Line. This should keep the Mid-Atlantic region within the warm sector. Consequently, a slew of weakly defined perturbations in the flow aloft track through overnight. As a result, light warm advection shower activity begins to lift northward from central Virginia near daybreak.
Forecast low temperatures will be in the 40s, with spotty low 50s inside D.C. and Baltimore, as well as near the Chesapeake Bay.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
For the weekend, Sunday presents the more unsettled of the two days. The 00Z HRRR solution shows the mentioned area of warm advection showers lifting across the region on Sunday morning before moving into northeastern Maryland by early in the afternoon. Once this wave of precipitation pivots out into the Delmarva region, high-resolution models break out scattered showers during Sunday afternoon/early evening. Depending on the degree of buoyancy in the atmosphere, a few rumbles of thunder cannot be ruled out. Any severe threat should stay off to the south near southeastern Virginia where a Marginal Risk exists.
Aside from these threats of showers, Sunday presents another mild day ahead of the blast of cold air to start the next work week. Forecast highs will again be in the mid 60s to low 70s, with 50s to low 60s for mountain locales. South to southwesterly breezes will gust up to 15 to 25 mph at times.

A potent cold front is forecast to approach the I-95 corridor by early Sunday evening. Scattered showers should accompany this boundary before quickly drying out. In the wake, an abrupt shift to westerly winds takes place which will become gusty over the higher terrain. Such gusts push into the 25 to 35 mph as cold advection ensues.

Any precipitation threats shift over to the Allegheny Front as supported by upslope aided trajectories. Showers that begin as rain will likely switch over to snow on Sunday night. An inch of accumulation is possible ahead of daybreak Monday. Overnight lows across the area should be fairly uniform east of the Blue Ridge with readings in the mid 30s to low 40s. The chilly spot will be the Alleghenies where 20s are anticipated. Adding the gusty 25 to 35 mph winds lowers wind chills down into the teens.

Periods of upslope driven snow showers continue along the Alleghenies on Monday. With Froude numbers staying in the 1 to 1.50 range, the resultant critical flow will not favor spillover snow showers farther downstream of the mountains. Another inch or two of snow is possible which would yield storm totals around 1 to 3 inches. On the temperature side, a cold blustery wind will certainly be a shock to the system. Monday's highs will be in the 40s to low 50s (20s to 30s for the mountains).
Corresponding wind chills drop into the 30s to 40s (single digits to teens across the mountains).

Another potent shortwave pivots across the Ohio Valley into Monday evening/night. This provides another uptick of winds, particularly across mountain locations. West-northwesterly winds gust up to 35 to 45 mph which could near advisory levels. This favors a very cold night on Monday, especially considering the reduced wind chills. Overnight temperatures fall into the 20s across the area which would yield freeze concerns where the growing season continues (King George, Calvert, and St. Mary's counties). Nighttime wind chils across the Alleghenies drop into the single digits.

LONG TERM /TUESDAY THROUGH FRIDAY/
The core of the cold air looks to pivot over the Mid-Atlantic on Tuesday. Near record cold 850 hPa temps around -10 C are expected which translates to surface temperatures only topping out in the 30s to around 40 (20s in the mountains). Drier air will rush in on gusty northwest breezes which could eclipse 30-40 mph at times. This will lead to wind chills staying below freezing most of the day, with teens and single digits above zero for the higher terrain.

Moderating temperatures are anticipated during the middle of next week ahead of a reinforcing cold front. The passage of this front may slow or halt the moderating trend in temperatures briefly, with high pressure set to build back into the region Friday.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
Despite all of the showers that have moved across the region, overall ceilings have remained on the higher side (6,000 to 8,000 feet). Current showers have now moved east of the terminals although will need to monitor the approaching stratus deck in the wake of the cold front. MVFR to IFR ceilings are currently being observed west of the Alleghenies. However, drier air should eventually win out behind this front with VFR conditions for today/tonight. Wind fields meander through the day with wind speeds staying 10 knots or less.

Light warm advection showers move in on Sunday morning. Aviation guidance shows some threat of restrictions, particularly east of the Blue Ridge. For now, will withhold lowering ceilings in the TAFs, but this will need to be monitored. Scattered showers are expected through Sunday afternoon with south-southwesterly gusts to around 15 to 20 knots. A powerful cold front tracks through on Sunday evening yielding a shift to gusty westerly winds into Sunday night. Such winds pick up on Monday given ample vertical mixing. While VFR conditions prevail on Monday, northwesterly winds should gust to around 20 to 25 knots or so. Wind fields stay somewhat elevated into Monday night as an additional disturbance aloft pushes through.

Mainly VFR Tue-Wed. W/NW flow gusting 25-35 kts Tue becomes S/SW with gusts 15-20 kts Wed.

MARINE
Ahead of the approaching cold front, southerly winds continue to gust to around 15 to 20 knots over the more southern waters.
Small Craft Advisories continue until 5 AM before dropping off.
The cold front moves across the waters early this morning which yields a shift to westerly winds. The weak nature of this system keeps winds well below advisory levels. As a secondary front nears the area tonight, southeasterlies pick up in strength on Sunday morning. These could near 15 to 20 knots, particularly if some channeling effects occur.

For the rest of Sunday, scattered showers move across the area.
This may be accompanied by a couple rumbles of thunder during the afternoon hours. Southerly channeling ahead of the stronger boundary would favor near 20 knot gusts on Sunday afternoon to early evening. This front crosses the waters on Sunday evening leading to a quick shift over to west-northwesterly winds. These remain gusty while becoming northwesterly into the night. Small Craft Advisories will be required at that point and continue into Monday. The strongest winds likely wait until Monday night given a secondary surge. Near gale conditions are possible across portions of the waters.

Latest model trends show a bit of an uptick in the wind forecast for Tuesday, which makes sense given the strength of cold air advection.
Gales are possible in this scenario. Lighter speeds out of the W/NW are likely Tuesday night, becoming S/SW Wednesday gusting 20-30 kt.

FIRE WEATHER
While rainfall amounts largely topped out in the 0.10 to 0.25 inch range, higher amounts have been observed around the Alleghenies (0.25 to 0.50 inches). This has provided a wetting rain for many. Behind a cold front tracking through early this morning, conditions dry out but with lighter winds expected.

A stronger cold front moves through late Sunday leading to more gusty winds, but much colder temperatures into next week. Another tenth to a quarter of an inch of precipitation is possible with the secondary front Sunday. Accumulating snow will also be concern for the Alleghenies. Even with all that said, additional fire weather concerns are possible Tuesday and Wednesday next week given gusty post frontal west to northwest flow. The one limiting factor could be the temperatures as they fall into the 40s during the daytime hours.

TIDES/COASTAL FLOODING
Tide levels have rebounded due to strong southerly winds as anomalies have risen into the 0.25 to 0.50 foot range. There won't be too much variation over the weekend without any strong offshore flow to push water away. Some locations may reach Caution/Action stage, but minor flooding is not expected. By Monday, the gusty post-frontal environment should lower water levels quite readily.

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Small Craft Advisory until 5 AM EST early this morning for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 5 AM EST early this morning for ANZ530>534-537-539>543.