Marine Weather Net

Tidal Potomac from Key Bridge to Indian Head MD Marine Forecast


REST OF TODAY

E
WINDS
5
KNOTS

TONIGHT

SE
WINDS
5 KNOTS

FRI

SE
WINDS
5 - 10
KNOTS

FRI NIGHT

SE
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ535 Forecast Issued: 1032 AM EDT Thu Jul 19 2018

Rest Of Today...E Winds 5 Kt. Waves Less Than 1 Ft.
Tonight...Se Winds 5 Kt. Waves Less Than 1 Ft.
Fri...Se Winds 5 To 10 Kt. Waves 1 Ft.
Fri Night...Se Winds 5 To 10 Kt. Waves 1 Ft.
Sat...E Winds 5 To 10 Kt. Waves 1 Ft. A Chance Of Showers And Tstms.
Sat Night...E Winds 5 To 10 Kt. Waves 1 Ft. A Chance Of Showers.
Sun...Se Winds 5 Kt. Waves Less Than 1 Ft. A Chance Of Tstms. Showers Likely.
Mon...S Winds 5 Kt. Waves Less Than 1 Ft. Showers Likely . Winds And Waves Higher And Visibilities Lower In And Near Tstms.
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Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1020am EDT Thu July 19 2018

Synopsis: High pressure over New York will move to New England by Friday. Developing low pressure in the Midwest will approach the area this weekend.

Near Term - Through Tonight
Only minor tweaks required to the forecast this morning to capture latest trends in sky/wind/temperature. Satellite shows morning stratocumulus dissipating with patches of cirrus stretching from the Ohio Valley to central Virginia. These clouds are gradually spreading north, but they won't be enough to completely obscure the sun.

The ridge of high pressure will remain centered north of the area today and tonight. Temperatures will climb into the middle to upper 80s by this afternoon. Dry conditions will continue through tonight as lows drop back into the 60s

Short Term - Friday Through Saturday Night
High pressure will slowly move toward New England Friday and then offshore later in the day into Friday night. Some diurnal cumulus clouds could develop Friday with developing warm advection. There shouldn't be much of a shower influence Friday. Most, of any, showers that do develop would be Friday night and across parts of the Potomac Highlands.

By Saturday, a strong upper level trough will extend from the Great Lakes southward across the Ohio and Tennessee River Valleys. This trough will interact with a stalled front off the southeast coast, developing a surface low along the coast. The GFS and Euro both depict this storm moving along the east coast Saturday and Saturday night. Both models tend to keep this system far enough east to avoid any direct impacts. These two features will act together to provide plenty of moisture and lift across the area for a chance at some showers and thunderstorms. This chance appears to be higher late Saturday, as a warm front lifts northward across the region. With unsettled weather expected much of the day, expecting temps to be below average, with highs in the upper 70s to low 80s

Long Term - Sunday Through Wednesday
An upper level and surface low will be stacked near the Ohio Valley Sunday morning as a surface warm front is forecast to be lifting northward into our area. On the eastern periphery of the aforementioned trough and associated mid level energy, expecting increased shower and thunderstorm chances during the day on Sunday, and continuing into Monday as the trough and surface boundary lingers nearby. The upper level trough should go on a weakening trend late Monday drifting southward into the southeast U.S. Precipitable water values will remain elevated (1.75-2.00") during this period as much of the region will reside in the moist sector under a southerly flow, and dewpoints will range in the upper 60s to low 70s much of the time.

A surface cold front and another digging upper level trough across the Great Lakes will be approaching to our west Tuesday and Wednesday, bringing an additional plume of moisture across the area. Will continue to advertise high end chance to likely POPs through midweek as a result. Temperatures through the extended period will run below normal for highs and near or slightly above normal for overnight lows thanks to ample cloud cover and elevated rain chances.

Marine Discussion
Early morning channeling/mixing of winds has decreased, with northeast winds becoming east later today at 5-10 kt. Winds may be near 15 kt on the open waters again tonight, but don't think an Small Craft Advisory will be warranted given high pressure nearby. Winds will become southeast on Friday, and could approach Small Craft Advisory criteria late in the day and overnight. The mid-Bay has the best chance at stronger winds as low pressure approaches from the southeast.

Small Craft Advisory conditions plausible Saturday and Saturday night as an upper level trough nears from the west, delivering showers and thunderstorms across the region. Any thunderstorms will be capable of producing locally gusty winds which may require the need for Special Marine Warnings should conditions warrant.

Low end Small Craft Advisory conditions are conceivable Sunday and into early next week as a warm front lifts through the waters on Sunday and stalls nearby. South southeasterly breezes will persist over the waters through Tuesday. With an upper level trough and surface boundary lurking nearby, expecting decent coverage of showers and storms through Tuesday, yielding the threat of locally gusty winds in and around thunderstorm activity. Special Marine Warnings may be required should conditions warrant

NOAA Baltimore MD/Washington DC Office: Watches - Warnings - Advisories
DC...None. MD...None. VA...None. WV...None. MARINE...None

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