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Marine Weather and Tides
Version 3.4 |
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome. 10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name. |
Sunrise 6:51AM | Sunset 5:52PM | Wednesday February 20, 2019 12:08 PM EST (17:08 UTC) | Moonrise 7:18PM | Moonset 7:46AM | Illumination 98% | ![]() |
ANZ535 Tidal Potomac From Key Bridge To Indian Head- 939 Am Est Wed Feb 20 2019
Rest of today..E winds 5 kt. Waves less than 1 ft. Snow or sleet late this morning, then sleet and rain or freezing rain this afternoon. Vsby 1 nm or less late this morning.
Tonight..W winds 5 kt. Waves less than 1 ft. Rain.
Thu..NW winds 5 kt. Waves less than 1 ft. Patchy fog. Vsby 1 to 3 nm.
Thu night..NW winds 5 kt. Waves less than 1 ft.
Fri..N winds around 5 kt. Waves 1 ft.
Fri night..Light winds. Waves 1 ft. Rain likely.
Sat..S winds around 5 kt. Waves 1 ft. Rain.
Sun..W winds 10 to 15 kt. Waves 1 ft. A chance of showers through the day.
Rest of today..E winds 5 kt. Waves less than 1 ft. Snow or sleet late this morning, then sleet and rain or freezing rain this afternoon. Vsby 1 nm or less late this morning.
Tonight..W winds 5 kt. Waves less than 1 ft. Rain.
Thu..NW winds 5 kt. Waves less than 1 ft. Patchy fog. Vsby 1 to 3 nm.
Thu night..NW winds 5 kt. Waves less than 1 ft.
Fri..N winds around 5 kt. Waves 1 ft.
Fri night..Light winds. Waves 1 ft. Rain likely.
Sat..S winds around 5 kt. Waves 1 ft. Rain.
Sun..W winds 10 to 15 kt. Waves 1 ft. A chance of showers through the day.
ANZ500 939 Am Est Wed Feb 20 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A strong low pressure system will impact the region throug tonight. Low pressure will then push off to the north and east on Thursday as a frontal boundary passes through the waters. High pressure will build to the north on Friday and another cold front will cross the waters on Sunday. Small craft conditions will be possible on Thursday, and likely on Sunday.
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A strong low pressure system will impact the region throug tonight. Low pressure will then push off to the north and east on Thursday as a frontal boundary passes through the waters. High pressure will build to the north on Friday and another cold front will cross the waters on Sunday. Small craft conditions will be possible on Thursday, and likely on Sunday.
7 Day Forecast for Marine Location Near Mount Vernon, VA
Hourly EDIT Helplocation: 38.68, -77.1 debug
Area Discussion for - Baltimore, MD/Washington
  (on/off)  Help NOTE: mouseover dotted underlined text for definitionFxus61 klwx 201520 afdlwx area forecast discussion national weather service baltimore md washington dc 1020 am est Wed feb 20 2019 Synopsis Low pressure will track from the mississippi valley into the great lakes today through tonight. Coastal low pressure will develop along the mid-atlantic coast tonight before moving off to our northeast Thursday. High pressure will return Thursday night and Friday before another low pressure impacts the area early next week. Near term through tonight Snow overspread the CWA this morning and is now transitioning to sleet and freezing rain across southern and western locations, including southern and western portions of maryland, central and northwestern virginia, and eastern west virginia. Snow persists at present from dc northwestward to hagerstown and points north and east, but the transition should continue sliding northeast across the remaining portions of the region through midday. Warming surface temps will then begin to spead across the region from southeast to northwest, allowing the sleet and freezing rain to change to plain rain, but this progress is notoriously hard to forecast and our confidence on this timing remains lower than we'd like. Will maintain headlines for now but may start to chop away at the winter storm warning in areas where it is becoming apparent that criteria is not being met, while as temps warm in southern md, we may start chipping away at the advisory. Precip should end as rain or a very marginal freezing rain late tonight across the region. Of note is that available instability aloft has been impressive enough to generate sporadict lightning strikes, and these may continue into the early afternoon as precip continues to transition from snow to ice. Short term Thursday through Friday night Cdfnt clears the area early on Thu with rain ending by 09z if not sooner. High pressure then builds over the area Thu night with next round of overrunning precip associated with developing southern plains cyclone beginning late Fri night. Given milder period ahead and high pressure at a more eastward position, this appears to be a mostly rain event except possibly in far nw maryland where some freezing rain is possible. Long term Saturday through Tuesday Warm front will be crossing the area Saturday, with more than enough isentropic lift to induce a swath of precipitation. Thermal profiles will be sufficiently warm for this to be all rain. With a trajectory off of the gulf of mexico, anticipate that moisture won't be a hinderance. Model guidance suggesting precipitable water will be exceeding an inch... And approaching an impressive (for february) 1.5 inches by Saturday night. Any remaining snow should be melted away, as temperatures drop little Saturday night in continued warm advection. But, the rainfall and snowmelt could lead to flooding concerns, as suggested by the naefs mmerf. Temperatures will continue to rise well into the 60s on Sunday ahead of a cold front, which may lead to additional showers. A tight thermal gradient should lead to strong cold advection, and thus windy conditions. High pressure will build across the northeast Monday-Tuesday. Since broad ridging remains 850-500 mb, temperatures don't drop considerably... And will remains at or above climo normals |
Monday, receding to near normal by Tuesday. (cold advection breezy conditions will continue into Monday.) with a jetmax along the central atlantic coast, systems will be progressive. Chance pops will return by the end of the day Tuesday. Aviation 15z Wednesday through Sunday Continuing lifr ifr conditions this morning as snow changes to sleet and freezing rain in the afternoon and eventually to rain late today or early this evening. Kmrb will be the last to change to rain not likely until 03z tonight. Rain ends late tonight around 09z with CIGS and vsbys improving. Flight restrictions (MVFR to ifr) likely this weekend in rain. Conditions may lift slightly Saturday night between warm and cold frontal passages. Marine Marginal SCA conditions possible this afternoon and evening. Otherwise, light winds 10 kt or less through Fri night. Light (at or below 10 kt) south winds Saturday as a warm front passes north of the waters. Mixing improves considerably Sunday behind a cold front. Small craft advisory conditions likely on Sunday. Lwx watches warnings advisories Dc... Winter storm warning until 7 pm est this evening for dcz001. Md... Winter storm warning until 7 pm est this evening for mdz005- 006-011-013-014-503>508. Winter storm warning until 1 am est Thursday for mdz003-004- 501-502. Winter weather advisory until 4 pm est this afternoon for mdz016>018. Va... Winter storm warning until 10 pm est this evening for vaz025- 026-036>038-503-504-507-508. Winter storm warning until 7 pm est this evening for vaz039- 050>054-502-506. Winter storm warning until 1 am est Thursday for vaz027>031- 040-501-505. Winter weather advisory until 4 pm est this afternoon for vaz055>057. Wv... Winter storm warning until 10 pm est this evening for wvz505- 506. Winter storm warning until 1 am est Thursday for wvz050>053- 055-501>504. Marine... Small craft advisory until 6 pm est this evening for anz531>533-539>542. Small craft advisory until 10 pm est this evening for anz534- 537-543. Synopsis... Lfr near term... Lfr rcm short term... Lfr long term... Hts aviation... Lfr hts rcm marine... Lfr hts rcm |
Weather Reporting Stations
EDIT (on/off)  Help NOTE: Click on distance to see the station location on a mapStations | Dist | Age | Wind | Air Temp | Water Temp | Waves | Pressure | DewPt |
WASD2 - 8594900 - Washington, DC | 14 mi | 39 min | ENE 2.9 G 5.1 | 30°F | 41°F | 1033.8 hPa | ||
BSLM2 - Chesapeake Bay, MD | 22 mi | 99 min | SE 6 | 30°F | 1033 hPa | 29°F | ||
NCDV2 | 25 mi | 45 min | ENE 1.9 G 2.9 | 31°F | 39°F | 1032.3 hPa | ||
TPLM2 - Thomas Point, MD | 38 mi | 69 min | ENE 8 G 9.9 | 29°F | 37°F | 1033.9 hPa (-1.1) | 29°F | |
APAM2 - 8575512 - Annapolis, MD | 39 mi | 39 min | 30°F | 1033.8 hPa | ||||
COVM2 - 8577018 - Cove Point LNG Pier, MD | 42 mi | 39 min | SE 4.1 G 16 | 31°F | ||||
SLIM2 - 8577330 - Solomons Island, MD | 42 mi | 39 min | E 8.9 G 11 | 32°F | 39°F | 1031.9 hPa | ||
CPVM2 | 44 mi | 39 min | 30°F | 30°F | ||||
FSKM2 - 8574728 - Francis Scott Key Bridge, MD | 48 mi | 39 min | ESE 7 G 8.9 | 29°F | 1034.4 hPa | |||
FSNM2 | 48 mi | 45 min | ENE 9.9 G 12 | 28°F | 1033.3 hPa | |||
PPTM2 - 8578240 - Piney Point, MD | 48 mi | 45 min | E 13 G 16 | |||||
BLTM2 - 8574680 - Baltimore, MD | 49 mi | 39 min | ESE 8 G 8.9 | 29°F | 38°F | 1033.7 hPa |
Wind History for Washington, DC
(wind in knots) EDIT (on/off)  Help12 PM | 1 PM | 2 PM | 3 PM | -12 PM | 5 PM | 6 PM | 7 PM | 8 PM | 9 PM | 10 PM | 11 PM | 12 AM | 1 AM | 2 AM | 3 AM | -12 PM | 5 AM | 6 AM | 7 AM | 8 AM | 9 AM | 10 AM | 11 AM | |
Last 24hr | NW G9 | W G11 | NW G11 | NW G8 | NW | NW G9 | NW | NE | NE | E | SE | E | SE | E | SE | SE G7 | SE G8 | E | E | E | E G7 | E G7 | ||
1 day ago | NW G21 | NW G24 | NW G18 | NW G23 | NW G28 | NW G19 | NW G18 | NW | N G14 | NW G19 | NW G18 | NW G16 | NW G13 | NW G14 | N G13 | N G11 | NW G11 | NW G16 | N G13 | NW G10 | NW G12 | N G10 | NW | NW |
2 days ago | S G8 | W | S | S | SE G11 | E | SE | S G8 | S | S | S | S G8 | S G16 | S G7 | S G13 | SW | W G7 | NW | SW | S | NW | NW G13 | NW G15 |
Airport Reports
EDIT (on/off)  Help Click EDIT to display multiple airportsAirport | Dist | Age | Wind kt | Visibility | Sky/Weather | Temp | DewPt | Humidity | Pressure |
Fort Belvoir, VA | 5 mi | 73 min | N 0 | 1.50 mi | Fog/Mist | 30°F | 27°F | 89% | 1032.9 hPa |
Washington/Reagan National Airport, DC, VA | 13 mi | 77 min | E 9 | 1.00 mi | Light Snow Fog/Mist | 31°F | 27°F | 85% | 1032.5 hPa |
Camp Springs / Andrews Air Force Base, MD | 16 mi | 73 min | ENE 7 | 1.00 mi | Light Snow Fog/Mist | 29°F | 27°F | 92% | 1032.9 hPa |
Quantico Marine Corps Airfield - Turner Field, VA | 16 mi | 73 min | E 5 | 2.00 mi | Light Freezing Rain Fog/Mist | 32°F | 30°F | 96% | 1033.2 hPa |
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA | 22 mi | 73 min | NNW 6 | 1.00 mi | Snow | 31°F | 28°F | 89% | 1035.7 hPa |
College Park Airport, MD | 23 mi | 86 min | N 0 | 1.00 mi | Overcast | 29°F | 26°F | 91% | 1033.2 hPa |
Wind History from DAA (wind in knots)
12 PM | 1 PM | 2 PM | 3 PM | 4 PM | 5 PM | 6 PM | 7 PM | 8 PM | 9 PM | 10 PM | 11 PM | 12 AM | 1 AM | 2 AM | 3 AM | 4 AM | 5 AM | 6 AM | 7 AM | 8 AM | 9 AM | 10 AM | 11 AM | |
Last 24hr | NW | NW | N | N | N | NW | NW | NW | N | Calm | Calm | Calm | Calm | Calm | Calm | E | E | SE | SE | Calm | E | E | E | Calm |
1 day ago | NW | N G18 | NW G28 | NW G28 | NW G29 | NW G29 | NW | NW G23 | NW G21 | NW G21 | NW G18 | NW | NW | NW | NW | NW G14 | NW | N | NW | Calm | N | NW | N | N |
2 days ago | E | SE | E | SE | SE | SE | SE | Calm | S | Calm | Calm | SE | SE | S | S | SW | W | Calm | Calm | Calm | Calm | Calm | W | NW G16 |
Tide / Current Tables for Marshall Hall, Maryland
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of DataMarshall Hall
Click for Map
Wed -- 02:22 AM EST -0.34 feet Low Tide
Wed -- 06:53 AM EST Sunrise
Wed -- 07:45 AM EST Moonset
Wed -- 08:20 AM EST 2.52 feet High Tide
Wed -- 02:39 PM EST -0.38 feet Low Tide
Wed -- 05:51 PM EST Sunset
Wed -- 07:17 PM EST Moonrise
Wed -- 08:44 PM EST 2.65 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Click for Map
Wed -- 02:22 AM EST -0.34 feet Low Tide
Wed -- 06:53 AM EST Sunrise
Wed -- 07:45 AM EST Moonset
Wed -- 08:20 AM EST 2.52 feet High Tide
Wed -- 02:39 PM EST -0.38 feet Low Tide
Wed -- 05:51 PM EST Sunset
Wed -- 07:17 PM EST Moonrise
Wed -- 08:44 PM EST 2.65 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
12 am | 1 am | 2 am | 3 am | 4 am | 5 am | 6 am | 7 am | 8 am | 9 am | 10 am | 11 am | 12 pm | 1 pm | 2 pm | 3 pm | 4 pm | 5 pm | 6 pm | 7 pm | 8 pm | 9 pm | 10 pm | 11 pm |
0.6 | 0.1 | -0.3 | -0.3 | 0.2 | 1 | 1.7 | 2.3 | 2.5 | 2.4 | 1.9 | 1.3 | 0.7 | 0.1 | -0.3 | -0.4 | -0 | 0.7 | 1.5 | 2.2 | 2.6 | 2.6 | 2.3 | 1.7 |
Tide / Current Tables for High Point, Occoquan Bay, Virginia
EDIT (on/off)  Help One Week of DataHigh Point
Click for Map
Wed -- 01:44 AM EST -0.24 feet Low Tide
Wed -- 06:53 AM EST Sunrise
Wed -- 07:20 AM EST 1.73 feet High Tide
Wed -- 07:46 AM EST Moonset
Wed -- 02:01 PM EST -0.28 feet Low Tide
Wed -- 05:51 PM EST Sunset
Wed -- 07:17 PM EST Moonrise
Wed -- 07:44 PM EST 1.82 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Click for Map
Wed -- 01:44 AM EST -0.24 feet Low Tide
Wed -- 06:53 AM EST Sunrise
Wed -- 07:20 AM EST 1.73 feet High Tide
Wed -- 07:46 AM EST Moonset
Wed -- 02:01 PM EST -0.28 feet Low Tide
Wed -- 05:51 PM EST Sunset
Wed -- 07:17 PM EST Moonrise
Wed -- 07:44 PM EST 1.82 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
12 am | 1 am | 2 am | 3 am | 4 am | 5 am | 6 am | 7 am | 8 am | 9 am | 10 am | 11 am | 12 pm | 1 pm | 2 pm | 3 pm | 4 pm | 5 pm | 6 pm | 7 pm | 8 pm | 9 pm | 10 pm | 11 pm |
0.1 | -0.2 | -0.2 | 0 | 0.5 | 1.1 | 1.5 | 1.7 | 1.7 | 1.4 | 0.9 | 0.5 | 0.2 | -0.1 | -0.3 | -0.1 | 0.3 | 1 | 1.5 | 1.8 | 1.8 | 1.6 | 1.2 | 0.8 |
Weather Map and Satellite Images
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GOES Local Image of 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 (12,3,4,5)
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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 numerious 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. |