Wednesday, January22, 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 7:20AMSunset 5:19PM Wednesday January 22, 2020 8:24 AM EST (13:24 UTC) Moonrise 5:37AMMoonset 3:16PM Illumination 7% Phase: Waning Crescent; Moon at 27 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- 638 Am Est Wed Jan 22 2020
Today..N winds 5 kt. Waves less than 1 ft.
Tonight..N winds around 5 kt. Waves 1 ft or less.
Thu..SE winds around 5 kt. Waves 1 ft or less.
Thu night..Light winds. Waves flat.
Fri..E winds around 5 kt. Waves 1 ft. A chance of rain.
Fri night..E winds 5 to 10 kt. Waves 1 ft. Rain.
Sat..E winds 5 to 10 kt...becoming w. Waves 1 ft. Rain likely through the day.
Sun..NW winds 5 to 10 kt. Waves 1 ft.
ANZ500 638 Am Est Wed Jan 22 2020
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will build overhead today, then move offshore by Friday. A low pressure system will approach on Saturday. Small craft advisories may be needed Friday night through Sunday.


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 220900 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 400 AM EST Wed Jan 22 2020

SYNOPSIS. High pressure will move overhead today and gradually transition offshore by Friday. Low pressure will approach from the central United States on Friday night, then slowly move toward New England during the second half of the weekend. High pressure will return early next week.

NEAR TERM /THROUGH TONIGHT/. Surface high pressure center is nearing the central Appalachians this morning while the mid and upper ridge axis is over the Mississippi Valley. Skies are clear to start, but some cirrus will be encroaching from the west as the day progresses, and especially into tonight. After starting in the teens and 20s this morning, daytime temperatures will moderate compared to the past two days due to the rising heights. Highs will range from the upper 30s to mid 40s. With the high remaining nearby through tonight, winds will remain light, thought cooling may be tempered a bit by the advancing clouds. Am still allowing some teens in the typically colder locations, with 20s elsewhere.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/. Ridging will advance to the east on Thursday. Mid and high clouds will continue to advance ahead of a trough digging into the center of the country. High temperatures will be a bit warmer, with most locations will reach the 40s. Low pressure will be developing in the Mississippi Valley Thursday night. While a few ensemble solutions offer a faster solution, there is good consensus among deterministic models that the nighttime hours will remain dry in our CWA (and in fact probably well into the day Friday). Lows will be warmer but still below freezing in many locations.

Moisture/lift associated with the low will spread into the area on Friday. There will be some dry air to overcome, so a slow onset makes sense. And most of the day could turn out dry along and east of roughly US 15. If precipitation begins quickly enough, there could be some spots below freezing west of the Blue Ridge, though am unsure if it would be valley locations, or on some of the ridges depending on how the column saturates to the wet bulb. It should be warm enough aloft for any such precipitation to be freezing rain versus snow. At this time, however, am expecting the bulk of the area to just see rain on Friday, with temperatures largely in the 40s by afternoon.

As the closed upper low moves into the Ohio Valley Friday night, a new low is expected to develop along the trailing frontal zone, likely somewhere near Virginia. There will be a good surge of moisture and lift with this low, and at a minimum, a period of moderate to briefly heavy precipitation is expected. Rainfall totals could near an inch in some locations. What is uncertain is the thermal profiles during this time, and how quickly cold air will arrive on the back side of this system. Eventually, a changeover to snow will occur along the Allegheny Front. The question is whether the cold air can arrive east of there before precipitation begins to exit. Even so, were there to be snow Friday night, the chances should be confined along and west of the Blue Ridge, and most likely at the higher elevations. The event will turn more upslope in nature as the low pulls away, which is discussed further in the long term section.

LONG TERM /SATURDAY THROUGH TUESDAY/. Mid to upper level trough and its cut-off low will be pushing ENE from the Midwest on Saturday. At the surface, occluded low pressure system will move from the Tennessee Valley into the Ohio Valley and Mid-Atlantic. Precipitation will be pushing from west to east on Saturday but conditions will be drying gradually through the day (except for the upslope areas). As this low pressure moves over our area and approaches the Mid-Atlantic coast, it will take a more NE track as it deepens. Lingering rain or snow showers possible into Saturday night. Greatest chance for any snow is at higher elevations, rain is expected elsewhere.

Low pressure will continue to move away from us Sunday into Monday. NW flow and shortwave energy aloft could bring additional upslope showers through Monday. High pressure will build over our area Monday night into Wednesday.

Temperatures during this period will be near or above normal for this time of the year with highs in the 40s and 50s (except at time over the ridges). Lows will be in the 20s and 30s.

AVIATION /09Z WEDNESDAY THROUGH SUNDAY/. VFR conditions will continue through Thursday as high pressure moves across the area. Northwest winds this morning will become light and variable as the day progresses, eventually taking on an east or southeast component.

Clouds will lower late Thursday night with MVFR ceilings and increasing rain chances Friday as low pressure approaches. IFR becomes more likely Friday night, along with a period of moderate rain, as the low moves overhead.

Sub-VFR conditions on Saturday with a low pressure system impacting our region. Conditions should improve later Saturday as the system moves away. Winds will increase on Sunday with VFR conditions remaining into Monday.

MARINE. North/northwest winds are finally starting to diminish on the waters as high pressure approaches from the west. By later today into Thursday, winds will become more northeasterly and should remain 10 kt or less. Winds will gradually increase Friday as low pressure approaches from the west, with Small Craft Advisory conditions becoming possible Friday night.

Periods of SCA conditions possible Saturday into Monday with low pressure moving across our area Saturday. Winds will increase behind this system Sunday and remain it into Monday with SCA conditions possible during this time.

LWX WATCHES/WARNINGS/ADVISORIES. DC . None. MD . None. VA . None. WV . None. MARINE . None.

SYNOPSIS . ADS NEAR TERM . ADS SHORT TERM . ADS LONG TERM . IMR AVIATION . ADS/IMR MARINE . ADS/IMR


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 5 mi55 min WNW 4.1 G 5.1 26°F 40°F1033.9 hPa
BSLM2 - Chesapeake Bay, MD 17 mi115 min Calm 1032 hPa
APAM2 - 8575512 - Annapolis, MD 32 mi55 min 25°F 1032.6 hPa
TPLM2 - Thomas Point, MD 32 mi25 min WNW 8 G 9.9 26°F 39°F1034.2 hPa (+1.9)18°F
NCDV2 33 mi55 min WNW 1.9 G 2.9 24°F 40°F1032.8 hPa
CPVM2 37 mi55 min 28°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 39 mi55 min N 8 G 9.9 27°F 1033.2 hPa
FSNM2 39 mi67 min NNW 8 G 9.9 26°F 1032.3 hPa
BLTM2 - 8574680 - Baltimore, MD 40 mi55 min N 5.1 G 8 27°F 44°F1032.8 hPa
SLIM2 - 8577330 - Solomons Island, MD 45 mi55 min NNW 5.1 G 7 26°F 42°F1032.8 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA4 mi33 minNNW 710.00 miFair25°F15°F66%1033.7 hPa
Camp Springs / Andrews Air Force Base, MD9 mi29 minN 010.00 miFair22°F15°F75%1033.9 hPa
Fort Belvoir, VA9 mi29 minN 010.00 miFair19°F13°F79%1034.2 hPa
College Park Airport, MD14 mi37 minN 010.00 miFair18°F12°F78%1033.2 hPa
Fort Meade / Tipton, MD24 mi37 minN 010.00 miFair18°F15°F93%1033.9 hPa

Link to 5 minute data for KDCA

Wind History from DCA (wind in knots)
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Last 24hrNW15N12N11N12N11N11N11N8NW12N12NW9NW8NW10N10NW8NW8NW8NW8NW6NW6NW5N5N5NW7
1 day agoNW13N15
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N14N13N10N7N6N8N9N11N12N10N8NW9NW8N9N9N11N10
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Tide / Current Tables for Alexandria, Virginia
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Alexandria
Click for Map
Wed -- 12:25 AM EST     -0.26 feet Low Tide
Wed -- 05:36 AM EST     Moonrise
Wed -- 06:01 AM EST     2.38 feet High Tide
Wed -- 07:21 AM EST     Sunrise
Wed -- 12:24 PM EST     -0.19 feet Low Tide
Wed -- 03:16 PM EST     Moonset
Wed -- 05:17 PM EST     Sunset
Wed -- 06:20 PM EST     2.79 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.2-0.20.311.72.22.42.21.610.50.1-0.2-0.10.41.21.92.52.82.72.31.71.20.7

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 (8,2,3,4)
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Ground Weather Radar Station Sterling, VA
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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.