Monday, March30, 2020
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Marine Weather and Tides
National Harbor, MD

Version 3.4
NOTICE
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.

Sunrise 6:53AMSunset 7:31PM Monday March 30, 2020 11:45 AM EDT (15:45 UTC) Moonrise 9:32AMMoonset 12:00AM Illumination 40% Phase: Waxing Crescent; Moon at 6 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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ANZ535 Tidal Potomac From Key Bridge To Indian Head- 1037 Am Edt Mon Mar 30 2020
.small craft advisory in effect through late tonight...
Rest of today..W winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft.
Tonight..NW winds 10 to 15 kt. Gusts up to 20 kt until early morning. Waves 1 ft.
Tue..NE winds 5 to 10 kt. Waves 1 ft.
Tue night..E winds 5 to 10 kt. Waves 1 ft. A chance of rain.
Wed..N winds 5 kt. Waves less than 1 ft. A chance of showers.
Wed night..NW winds 5 kt. Waves less than 1 ft.
Thu..NW winds 5 to 10 kt. Waves 1 ft.
Fri..S winds around 5 kt. Waves 1 ft.
ANZ500 1037 Am Edt Mon Mar 30 2020
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A secondary cold front approaching from the great lakes will cross the mid-atlantic today. High pressure will build in its wake tonight into Tuesday before low pressure passes well to the south Tuesday night into Wednesday. High pressure will follow into the first half of the weekend. A small craft advisory will likely be needed Tuesday night into Wednesday, and may be needed Thursday.


7 Day Forecast for Marine Location Near National Harbor, MD
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location: 38.8, -77.03     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 301425 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1025 AM EDT Mon Mar 30 2020

SYNOPSIS. A secondary cold front approaching from the Great Lakes will cross the Mid-Atlantic today. High pressure will build in its wake tonight into Tuesday before low pressure passes well to the south Tuesday night into Wednesday. High pressure will follow into the first half of the weekend. A cold front may approach by early next week.

NEAR TERM /THROUGH TUESDAY/. The marine layer has been stubborn to erode, but appears to be doing to per last half hour of satellite imagery. A secondary cold front appears poised to cross the Appalachians, promoting deep mixing which will finally scour out the low-level moisture. Mean momentum transfer should support wind gusts in the mid 20s (knots). Airmass remains fairly warm, which will only be aided by downslope flow, so raised high temps by a degree or two.

Cooler air builds south across the region tonight with high pressure and dwindling winds. Temps will be cooler than they've been in several days, but still only near normal for this time of year. A stray shower can't be ruled out overnight as a weak disturbances passes.

Clouds will increase on Tuesday as a backdoor front drops southeast across the area and low pressure approaches from the southwest. This low will only give us a glancing blow, but a few showers may develop with the back door front as well. Temperatures will be cooler with the clouds and overall cooler Canadian air mass, with highs only in the 50s.

SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/. Low pressure passes to the south and then off the coast Tuesday night into Wednesday. Best chance of rain is Tuesday night, but some showers may linger Wednesday with upper level forcing and some surface convergence. Highest elevations of the mountains may see an inch or two of snow, but not advisory criteria. System heads out to sea by Wednesday night with decreasing clouds. Low Tuesday night will remain seasonable, but highs Wednesday will be on the cool side for this time of year once again, with 50s common. Lows Wednesday night mainly in the 30s.

LONG TERM /THURSDAY THROUGH SUNDAY/. High pressure is expected to retain control of the weather pattern over the Mid-Atlantic Thursday into the first half of the weekend. This will lead to gradually warming temperatures and mainly dry conditions. A cold front may approach Sunday into Monday bringing the next chance of rain. Model guidance has trended slower with this front, though spread is still large.

AVIATION /14Z MONDAY THROUGH FRIDAY/. Low clouds and fog finally starting to scour out. Terminals have achieved VFR, and should remain so for the rest of today. west/northwest winds should support gusts in the mid 20s (knots) this afternoon.

Winds diminish tonight but should remain VFR. Conditions may deteriorate later Tuesday as low- level easterly flow redevelops, with sub-VFR conditions most likely Tuesday night into Wednesday as low pressure passes south of the area and then off the coast. Conditions likely improve to VFR Wednesday night.

Mainly VFR expected Thu-Fri in NW flow (G20 kts possible).

MARINE. Low pressure moving away from the region with high pressure building in will allow gusty winds across the waters today. They may be marginal, but will keep SCA issued previously for all waters through this evening. Gusts diminish overnight with high pressure, but as low pressure passes to the south and strengthens Tuesday night and Wednesday, SCA may again be needed.

Northwesterly flow is expected with gusts exceeding 20 knots possible Thursday into Friday morning, likely becoming lighter by Friday afternoon as high pressure builds.

FIRE WEATHER. Gusty northwest winds and low humidity are expected today across central Virginia as high pressure builds in. Relative humidity will drop below 30 percent across much of Virginia this afternoon as winds increase to 15 to 20 mph (gusts up to 30 mph). Issued a Special Weather Statement to highlight risk, focusing on central Virginia. Fuels in Maryland are too moist and RH not forecast to drop below 30%.

TIDES/COASTAL FLOODING. Water levels running about a foot to a foot and a half above astronomical normals this morning. At this level, the tide fell about an inch or two short of minor at Straits Point and it looks like it'll just hit the minor threshold at Annapolis. Will hold onto Anne Arundel's Advisory until the tide reaches the mouth of the Patapsco. Will also be monitoring SW DC.

Departures will remain high for the next couple of days, although there should be a brief decline with northwest winds picking up later today.

LWX WATCHES/WARNINGS/ADVISORIES. DC . None. MD . Coastal Flood Advisory until 2 PM EDT this afternoon for MDZ014. VA . None. WV . None. MARINE . Small Craft Advisory until 2 AM EDT Tuesday for ANZ530>543.

SYNOPSIS . DHOF NEAR TERM . HTS/RCM SHORT TERM . RCM LONG TERM . DHOF AVIATION . HTS/RCM/DHOF MARINE . RCM/DHOF FIRE WEATHER . HTS TIDES/COASTAL FLOODING . HTS


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 5 mi46 min S 8 G 9.9 58°F 55°F1014.2 hPa (-2.0)
BSLM2 - Chesapeake Bay, MD 17 mi136 min S 5.1 1015 hPa
APAM2 - 8575512 - Annapolis, MD 32 mi46 min 61°F 1013.3 hPa (-2.1)
TPLM2 - Thomas Point, MD 32 mi46 min SSE 11 G 12 52°F 51°F1014.9 hPa (-1.9)52°F
NCDV2 33 mi46 min SSE 6 G 8 1014.4 hPa (-1.2)
44062 - Gooses Reef, MD 37 mi22 min S 5.8 G 5.8 54°F
CPVM2 37 mi46 min 53°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 39 mi46 min SSE 6 G 8 58°F 1013.4 hPa (-2.2)
FSNM2 39 mi82 min S 7 G 8.9 58°F 1013.6 hPa
BLTM2 - 8574680 - Baltimore, MD 40 mi46 min WSW 2.9 G 6 60°F 53°F1013.2 hPa (-2.0)
COVM2 - 8577018 - Cove Point LNG Pier, MD 44 mi46 min S 8 G 9.9 1015.1 hPa (-1.4)
SLIM2 - 8577330 - Solomons Island, MD 45 mi46 min SW 8 G 8.9 56°F 53°F1014.8 hPa (-1.1)

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA4 mi54 minS 910.00 miA Few Clouds59°F52°F78%1014.3 hPa
Camp Springs / Andrews Air Force Base, MD9 mi1.8 hrsS 310.00 miPartly Cloudy55°F52°F88%1015.6 hPa
Fort Belvoir, VA9 mi50 minSSE 710.00 miFair61°F51°F71%1014.5 hPa
College Park Airport, MD14 mi61 minS 510.00 miPartly Cloudy58°F47°F67%1013.9 hPa
Fort Meade / Tipton, MD24 mi61 minSSW 510.00 miPartly Cloudy59°F50°F72%1014.6 hPa

Link to 5 minute data for KDCA

Wind History from DCA (wind in knots)
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Last 24hrS5E10S8S5S7S6CalmCalmNE13NE12NE7NE5NE5NE7NE5E4NE7NE7NE3E4S4S7S10S9
1 day agoS4E5E3E6E7E6E7NE11NE7N15NE11NE8NE6N3NE3N6NE8NE5E4CalmNE4NE3CalmCalm
2 days agoN5NE7N7N4N9N7NE3CalmSE9S4S6CalmS3CalmN3CalmS4CalmNE6NE5E4E9E10E6

Tide / Current Tables for Alexandria, Virginia
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Alexandria
Click for Map
Mon -- 12:37 AM EDT     Moonset
Mon -- 12:43 AM EDT     2.68 feet High Tide
Mon -- 06:46 AM EDT     0.43 feet Low Tide
Mon -- 06:55 AM EDT     Sunrise
Mon -- 10:32 AM EDT     Moonrise
Mon -- 12:42 PM EDT     3.11 feet High Tide
Mon -- 07:30 PM EDT     Sunset
Mon -- 07:45 PM EDT     0.47 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.62.72.521.40.90.50.40.611.82.533.12.82.31.81.20.80.50.50.61.11.8

Tide / Current Tables for Riverview, Potomac River, Maryland
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Weather Map
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wmap_A
GEOS Local Image of Mid-Atlantic    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop



Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Baltimore, MD/Washington (11,2,3,4)
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Ground Weather Radar Station Sterling, VA
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Disclaimer:
The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerous of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.