Friday, April10, 2020
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Marine Weather and Tides
Potomac Heights, 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 6:37AMSunset 7:42PM Friday April 10, 2020 2:12 PM EDT (18:12 UTC) Moonrise 10:02PMMoonset 7:32AM Illumination 91% Phase: Waning Gibbous; Moon at 18 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- 138 Pm Edt Fri Apr 10 2020
.gale warning in effect until 6 pm edt this evening...
.small craft advisory in effect from 6 pm this evening to midnight edt tonight...
This afternoon..NW winds 20 kt with gusts to 40 kt. Waves 2 ft.
Tonight..NW winds 15 to 20 kt with gusts to 30 kt... Becoming W 5 to 10 kt with gusts to 20 kt in the late evening and overnight. Waves 1 to 2 ft.
Sat..W winds 5 to 10 kt. Waves 1 ft.
Sat night..SE winds around 5 kt. Waves 1 ft. A chance of showers.
Sun..S winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft. A chance of showers.
Sun night..S winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft. Showers.
Mon..S winds 15 kt...becoming sw in the afternoon, then becoming W 5 to 10 kt. Waves 1 to 2 ft. Showers with a chance of tstms through the day, then a chance of showers in the evening.
Tue..NW winds 5 to 10 kt. Waves 1 ft. A chance of rain through the night. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 138 Pm Edt Fri Apr 10 2020
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Strong and gusty westerly winds will persist over the waters today before high pressure gradually builds overhead tonight through Saturday. The high will then shift offshore Saturday night as low pressure tracks to our west Sunday night into Monday, ushering a cold front through the waters Monday evening. Small craft advisories will likely be required for a portion of the waters on Saturday, then again on Sunday, with gale conditions possible late Sunday night into Monday.


7 Day Forecast for Marine Location Near Potomac Heights, MD
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location: 38.62, -77.13     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 101433 AAA AFDLWX

Area Forecast Discussion . UPDATED National Weather Service Baltimore MD/Washington DC 1033 AM EDT Fri Apr 10 2020

SYNOPSIS. Low pressure will remain over the Canadian Maritimes today while high pressure builds over the Midwest. The high will build overhead tonight through Saturday before moving offshore Sunday. Strong low pressure and its associated cold front will impact the are Sunday night into Monday. The cold front will stall out to the south for the middle portion of next week, and waves of low pressure may track along the boundary, bringing the potential for unsettled conditions.

NEAR TERM /THROUGH TONIGHT/.

Cold air aloft (-26.6C at 500 mb) and passing of shortwave- trough are causing more than clouds than previously expected. Have raised sky cover grids to indicate a mostly cloudy day. Otherwise, rest of the fcst remains the same. Still very windy day today with gusts 45 to 50 mph, a tad lower than yesterday.

Previous afd .

An upper-level trough will remain overhead today while strong low pressure remains over the Canadian Maritimes. The pressure gradient will remain strong between this low and high pressure that will be building over the Midwest. Therefore, more windy conditions are expected with frequent gusts around 40 to 50 mph for most locations. A Wind Advisory for gusts around 50 mph is in effect for the Washington and Baltimore Metro areas, northern Virginia, eastern West Virginia, northern and central Maryland, and the higher elevations of the Blue Ridge and Potomac Highlands. Elsewhere, across central Virginia and southern Maryland, wind gusts are more likely to be around 40 mph.

A few rain and snow showers are possible in the Potomac Highlands today, but any additional precipitation amounts will be light. Did add the chance for a sprinkle or flurry further east toward the metro areas, and the reasoning for this was limited instability developing underneath the subsidence inversion along with an embedded shortwave passing through in the longwave upper-level trough. Otherwise, dry conditions are expected with a partly to mostly sunny sky (sct-bkn cu deck).

High pressure will build toward the region tonight, and winds will diminish after sunset. With light winds overnight and mainly clear skies, temperatures will turn out chilly for this time of year. Min temps will most likely range from the 20s in the mountains, to the lower and middle 30s for most other areas (upper 30s in downtown Washington and Baltimore). A Freeze Watch continues for areas northwest of Interstate 95. Despite the decreasing winds, do feel that the winds should be just strong enough in most areas to prevent widespread frost from developing.

SHORT TERM /SATURDAY THROUGH MONDAY/. High pressure will build overhead Saturday, bringing dry conditions along with sunshine. It will turn out a little milder, but still a few degrees below climo.

The high will move offshore Saturday night and a return flow will develop. Saturday night will not be as chilly as Friday night due to more high and mid-level clouds along with the light return flow. Min temps will be in the upper 30s to lower 40s for most areas. Patchy frost cannot be ruled out in some of the colder valleys, but with the clouds and the return flow it should remain isolated at best.

High pressure will continue to move offshore Sunday while low pressure in the southern stream of the jet moves through the southern Plains toward the Gulf Coast States. An upper-level trough over the Rockies into central CONUS will continue to dig, which is shown in guidance by it becoming more meridional.

The southern stream system will tap into moisture from the Gulf of Mexico, and that warm and moist air will begin to overrun cooler air in our area. Therefore, high and mid-level clouds are expected to increase, but the latest trend in guidance has been to slow this system down just a bit. Therefore, much of Sunday is most likely to turn out dry. Still cannot rule out an isolated shower out of a mid-level cloud deck as an upper-level disturbance passes through.

The southern stream low over the Gulf Coast States will track northwest, west of the Appalachians and into the Great Lakes Sunday night into Monday. This system will continue to strengthen during this time. The upper-level trough axis will turn negatively tilted during this time, and the cold front associated with this low will approach from the west. Plenty of moisture, along with a potent jet stream at the low, mid, and upper- levels means that rain is expected Sunday night into Monday. Rain may be heavy due to the copious amounts of moisture and strong forcing from the jet dynamics. Also, with a very strong wind field, there is a threat for severe thunderstorms. Confidence is still low due to limited instability, but even a little instability may be enough to cause locally damaging winds and perhaps a spin up. The best chance for this to occur would be late Sunday night through midday Monday just ahead of a dry slot.

The dry slot should move in later Monday, allowing for conditions to improve. Warm conditions along with some sunshine are most likely Monday afternoon ahead of the cold front. Still cannot rule out a couple showers ahead of the cold front, but the dry slot appears to be quite strong so any coverage appears that it will be limited. Will have to watch the overall timing of this system, because if it trends a little slower, then much more shower and thunderstorm activity could persist through Monday afternoon.

LONG TERM /MONDAY NIGHT THROUGH THURSDAY/. Behind the frontal passage late Monday, high pressure over the central U.S. will nudge into the region Monday night with drier conditions prevailing. Could be some upslope snow showers along the Allegheny Front Monday evening as CAA and WNW flow takes hold, but both those features don't look overly impressive at this time. The high will allow dry condtions to persist through the day on Tuesday as temperatures remain just below normal for the middle of April.

Thereafter, conditions look to return to an unsettled nature once again late Tuesday night through Thursday as the upper trough taking residence over the Great Lakes tracks shortwave energy into the Mid- Atlantic and Northeast. At the surface, low pressure may develop along a stalled frontal boundary lingering across the Southeast late Tuesday night into Wednesday, passing through the Carolinas and bringing our next shot of rain. Brief high pressure looks to build over the area Wednesday night before the primary upper trough axis lifts to our northeast on Thursday, allowing the flow to turn more zonal. Expect temperatures to run slightly below normal through the middle portion of next week, with a frost/freeze potential existing each night beginning Tuesday night.

AVIATION /14Z FRIDAY THROUGH TUESDAY/. Strong northwest winds will continue today with gusts around 35 to 40 knots. The strongest winds are expected mid-morning through the afternoon. Winds will quickly diminish after sunset as high pressure builds overhead. High pressure will remain overhead through Saturday, before moving offshore Saturday night.

Low pressure will strengthen as it approaches Sunday and passes by to the west Sunday night into Monday. SubVFR conditions along with widespread showers are expected, especially Sunday night into Monday. Very strong winds are expected just above the surface (60-80 knots from the south to southwest at 3-5kft). This will likely cause wind shear issues. A portion of those winds may mix down to the surface Sunday night into Monday, bringing the potential for damaging gusts, especially in heavier showers and possible thunderstorms.

A dry slot should cause conditions to improve Monday afternoon. Timing of this system is still uncertain, but as of now it appears the worst conditions are expected overnight Sunday through midday Monday.

In the wake of a frontal passage late Monday, high pressure will build over the terminals Monday night through the day on Tuesday with VFR conditions prevailing with gusty WNW winds. Low pressure passing south of the terminals late Tuesday night could return sub VFR conditions in low CIGs and increasing rain chances, while WNW winds trend light at 10 knots or less.

MARINE. Strong northwest winds will continue through this afternoon, and a Gale Warning is in effect for gusts around 35 to 40 knots. Winds will gradually diminish tonight, but a Gale Warning remains in effect for the Bay this evening and a Small Craft Advisory is in effect for the Potomac River. A Small Craft Advisory is in effect for the Bay and lower Tidal Potomac River overnight.

West to northwest winds may gust around SCA criteria over portions of the waters Saturday before high pressure builds overhead Saturday night.

High pressure will move offshore Sunday and a return flow will develop. An SCA may be needed for portions of the waters. Strong low pressure will pass by to the west Sunday night into Monday, and this will lead to the potential for strong southerly winds along with showers and possible thunderstorms. Damaging wind gusts are possible, especially in any heavier showers or thunderstorms. A Gale Warning may be needed for the waters during this time. Conditions may improve some Monday afternoon as the gradient subsides and a dry slot moves in aloft. However, timing of this is till uncertain.

Gusty westerly breezes Monday night will persist across the waters into the day on Tuesday, with SCA conditions likely for at least a portion of the waters. As the gradient relaxes a touch Tuesday night, westerly breezes seem poised to remain below SCA thresholds.

FIRE WEATHER. Lots of clouds this morning and lack of dry signature on mid and upper level water vapor channels on current GOES imagery and simulated imagery will likely prevent Rh from dropping to critical levels. Model trends in dewpoints show values remaining steady while temps only rise a few more degs due to continued cold air advection. With well-mixed bdry layer this morning, don't see Rh values dropping much further than what they are right now. Winds will still be strong nonetheless. Think SPS will suffice for today. Biggest concern seems to be over southern VA and North Carolina.

TIDES/COASTAL FLOODING. Strong southerly flow will allow tidal anomalies to rise sharply late Sunday through Monday before a cold front crosses the area late Monday and winds turn out of the northwest. As a result, minor to moderate tidal flooding will be possible during the high tide cycles Sunday night and Monday.

LWX WATCHES/WARNINGS/ADVISORIES. DC . Wind Advisory until 6 PM EDT this evening for DCZ001. MD . Freeze Watch from late tonight through Saturday morning for MDZ003>006-503-505-507. Wind Advisory until 6 PM EDT this evening for MDZ003>006-011- 013-014-501>508. VA . Freeze Watch from late tonight through Saturday morning for VAZ025>031-038>040-050>052-501-502-505>508. Wind Advisory until 6 PM EDT this evening for VAZ025>031-053- 054-501-503>508. WV . Freeze Watch from late tonight through Saturday morning for WVZ051>053. Wind Advisory until 6 PM EDT this evening for WVZ050>053-055- 501>506. MARINE . Small Craft Advisory from midnight tonight to 6 AM EDT Saturday for ANZ530>534-538>541-543. Gale Warning until midnight EDT tonight for ANZ530>534-538>541- 543. Small Craft Advisory from 6 PM this evening to midnight EDT tonight for ANZ535-536. Gale Warning until 6 PM EDT this evening for ANZ535>537-542. Small Craft Advisory from 6 PM this evening to 6 AM EDT Saturday for ANZ537-542.

SYNOPSIS . LFR NEAR TERM . LFR SHORT TERM . BJL LONG TERM . BKF AVIATION . BKF/LFR MARINE . BKF/LFR FIRE WEATHER . LFR TIDES/COASTAL FLOODING . BJL


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 18 mi55 min NW 17 G 26 49°F 59°F1006.1 hPa
NCDV2 21 mi61 min NW 11 G 22 49°F 58°F1005.5 hPa
BSLM2 - Chesapeake Bay, MD 25 mi103 min WNW 14 1004 hPa
44062 - Gooses Reef, MD 38 mi37 min WNW 25 G 33 48°F
SLIM2 - 8577330 - Solomons Island, MD 41 mi55 min W 13 G 29 49°F 55°F1004.9 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 42 mi67 min WNW 25 G 32 1005.2 hPa
TPLM2 - Thomas Point, MD 42 mi73 min W 31 G 35 46°F 52°F1005.1 hPa (+1.5)22°F
APAM2 - 8575512 - Annapolis, MD 43 mi61 min 49°F 1003.6 hPa
PPTM2 - 8578240 - Piney Point, MD 46 mi55 min NW 32 G 42
CPVM2 47 mi55 min 48°F

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA8 mi77 minWNW 18 G 2910.00 miPartly Cloudy and Breezy50°F19°F29%1006 hPa
Quantico Marine Corps Airfield - Turner Field, VA12 mi77 minWNW 23 G 3410.00 miMostly Cloudy and Windy51°F21°F31%1007 hPa
Washington/Reagan National Airport, DC, VA17 mi81 minWNW 25 G 3510.00 miMostly Cloudy and Windy50°F23°F35%1005.6 hPa
Camp Springs / Andrews Air Force Base, MD20 mi77 minW 19 G 3210.00 miMostly Cloudy and Breezy48°F20°F34%1005.8 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA22 mi77 minNW 20 G 2610.00 miOvercast and Breezy49°F21°F35%1007 hPa
Stafford, Stafford Regional Airport, VA23 mi78 minWNW 21 G 3210.00 miMostly Cloudy and Breezy51°F19°F29%1008.5 hPa

Link to 5 minute data for KDAA

Wind History from DAA (wind in knots)
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NW8N3CalmCalmCalmCalmCalmCalmCalmCalmCalmNW3SE3CalmCalmS3SW6W8
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2 days agoSE4CalmN3SE5S4CalmSE3CalmCalmS3CalmCalmCalmCalmN7
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Tide / Current Tables for Glymont, Maryland
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Glymont
Click for Map
Fri -- 03:55 AM EDT     -0.03 feet Low Tide
Fri -- 06:38 AM EDT     Sunrise
Fri -- 08:31 AM EDT     Moonset
Fri -- 09:43 AM EDT     2.42 feet High Tide
Fri -- 04:43 PM EDT     -0.11 feet Low Tide
Fri -- 07:40 PM EDT     Sunset
Fri -- 10:20 PM EDT     2.09 feet High Tide
Fri -- 11:01 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.30.80.40.1-00.20.71.422.42.42.11.71.20.70.3-0-0.10.20.81.41.92.12

Tide / Current Tables for Mount Vernon, Virginia
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Mount Vernon
Click for Map
Fri -- 04:26 AM EDT     -0.04 feet Low Tide
Fri -- 06:38 AM EDT     Sunrise
Fri -- 08:31 AM EDT     Moonset
Fri -- 10:13 AM EDT     2.95 feet High Tide
Fri -- 05:14 PM EDT     -0.14 feet Low Tide
Fri -- 07:40 PM EDT     Sunset
Fri -- 10:50 PM EDT     2.54 feet High Tide
Fri -- 11:01 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.91.30.70.3000.51.32.12.72.92.82.31.71.10.60.2-0.1-00.51.322.42.5

Weather Map
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GEOS 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 (14,3,4,5)
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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 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.