Sunday, September27, 2020
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L-36.com

Marine Weather and Tides
Alexandria, VA

Version 3.4
NOTICE
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
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 6:59AMSunset 6:58PM Sunday September 27, 2020 3:15 AM EDT (07:15 UTC) Moonrise 4:21PMMoonset 1:37AM Illumination 76% Phase: Waxing Gibbous; Moon at 10 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- 137 Am Edt Sun Sep 27 2020
Overnight..E winds 5 kt. Waves flat. Isolated showers. Areas of fog. Vsby 1 to 3 nm.
Sun..S winds around 5 kt. Waves 1 ft. Areas of fog. Vsby 1 to 3 nm.
Sun night..S winds 5 kt. Waves less than 1 ft.
Mon..S winds 5 to 10 kt. Waves 1 ft.
Mon night..S winds 5 to 10 kt. Waves 1 ft. A chance of showers.
Tue..S winds 5 to 10 kt. Waves 1 ft. Showers with a chance of tstms.
Tue night..W winds around 5 kt. Waves 1 ft. Showers likely with a chance of tstms.
Wed..NW winds around 5 kt. Waves 1 ft. Showers likely, mainly in the morning.
Thu..NW winds around 5 kt. Waves 1 ft. A chance of showers. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 137 Am Edt Sun Sep 27 2020
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A weak high pressure system will sit over the region through Monday. A pair of cold fronts are expected to move across the waters during the middle portion of next week. Small craft advisories may be needed for portions of the waters Sunday night through the middle of next week.


7 Day Forecast for Marine Location Near Alexandria, VA
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location: 38.83, -77.04     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 270056 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 856 PM EDT Sat Sep 26 2020

SYNOPSIS. A ridge of high pressure will build over the region through Sunday. A series of cold fronts will impact the region during the middle portion of next week.

NEAR TERM /UNTIL 6 AM SUNDAY MORNING/. A mid-level ridge of high pressure will build from the west. A few lingering showers over the Chesapeake Bay and southern Maryland will dissipate late this evening. A moist ground and low-level moisture should result in widespread areas of fog which could be locally dense after midnight. Guidance continues to strongly suggest widespread fog advisory, but given lingering clouds, will hold off on a pre-emptive fog advisory, especially since history of them has repeatedly shown a lack of skill with any fog advisories more than a couple hours in advance. Will closely monitor conditions however, and have adjusted the forecast in preparation of an advisory overnight.

SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/. Warm and nice day is expected Sunday with mid-level ridge overhead after fog dissipates. No precip is expected along and west of the I-95 corridor. We can't rule out a few showers near the Bay shoreline as a weak shortwave- trough along the Atlantic Coast and Delmarva moves northeastward and out of the area by Sunday night.

Sunday night should be dry in all areas. Isolated POPs Monday into Monday night as a persistent southerly flow develops and some weak energy pushes in from the southwest. A few showers around Monday night, but nothing too widespread or heavy.

LONG TERM /TUESDAY THROUGH SATURDAY/. A highly sinusoidal longwave pattern will be in place to start the period with a split jet structure noted in many of the global models. A region of lower heights currently over far northern Manitoba is the likely genesis region for a rather potent shortwave primed to move through the Tennessee Valley on Tuesday. The previous two model cycles (12Z/00Z) have trended southward leading to more a cut off solution as the system lifts out of the southern Appalachians late Tuesday/early Wednesday. Multiple waves of low pressure may form along the baroclinic zone with current ensembles bringing the cyclone centers from the Carolinas toward the Delmarva region. Accompanying this system is an impressive upper jet streak with recent models bringing 150 to 170 knot winds through interior New England. The Mid-Atlantic sits on the favorable right entrance region of this intense jet maxima which supports a fairly potent late September system. Recent GEFS ensembles show precipitable water values peaking into the 1.50 to 1.75 inch range which is in the 90th to 95th percentile in terms of moisture. All and all, the possibility of moderate to heavy rainfall exists during the Tuesday through Wednesday timeframe with uncertainty in timing and placement.

By Thursday into Friday, a cool post-frontal air mass will be in place with cold air advection significantly lowering temperatures. After beginning the week in the upper 70s to low 80s, broad cyclonic flow across the eastern half of the country will ensure a pronounced cooling trend. Current ensembles bring highs down into the low/mid 60s while overnight temperatures drop into the low/mid 40s. Conditions should dry out to close out the work week with the drying trend dependent on how quickly the system exits the Mid- Atlantic.

AVIATION /01Z SUNDAY THROUGH THURSDAY/. MVFR is the main theme presently, with spotty IFR and VFR mixed in. A few showers persist near the bay. Guidance continues to insist that widespread areas of dense fog may develop late tonight with IFR/LIFR restrictions. Have included in TAFs for now. No sig wx is expected Sunday or Monday.

Given the increasing chances for showers with isolated thunderstorms, reduced visual flight rules are likely on Tuesday and Wednesday given periods of lowering ceilings and visibilities. Locally gusty winds are also possible within any of the heavier shower activity. Forecast uncertainty exists with details being ironed out in future discussions.

MARINE. Winds may strengthen Sunday night and remain gusty through the middle portion of next week. SCAs may become necessary.

Small Craft Advisory issuances are likely on Tuesday with occasional breezy southerly winds in advance of the cold front. For the following day, there will be periods approaching criteria, especially in the vicinity of any heavy showers.

EQUIPMENT. The KLWX (Sterling, VA) WSR-88D remains out of service until further notice. The outage is due to a failure within the Radar Data Acquisition Functional Area that occurred early in the morning on September 20, 2020.

Saturday morning, technicians from the National Weather Service Radar Operations Center diagnosed a failure in the bull-gear. This will cause a lengthy delay in returning KLWX WSR-88D to service. Staff from the WSR-88D Radar Operations Center, NWS Eastern Region Headquarters, and the Baltimore/Washington Weather Forecast Office (WFO) will meet Monday, September 28 to determine the next steps. At that time, we will provide you with another update on the repair and expected time to return KLWX to service. At this point, the radar will be out of service for at least another week or two.

Users of KLWX can utilize adjacent weather radars located in Dover DE (KDOX), Mt. Holly NJ (KDIX), Pittsburgh PA (KPBZ), Charleston WV (KRLX), Blacksburg VA (KFCX), and Wakefield VA (KAKQ).

Further updates to keep users informed about the situation will be issued as information becomes available. Thank you for your understanding during this extended outage.

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

SYNOPSIS . KLW NEAR TERM . KLW/RCM SHORT TERM . KLW LONG TERM . BRO AVIATION . BRO/KLW/RCM MARINE . BRO/KLW/RCM EQUIPMENT . LWX


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 3 mi46 min NNE 1 G 2.9 68°F 69°F1014.7 hPa
BSLM2 - Chesapeake Bay, MD 18 mi106 min Calm 1014 hPa
APAM2 - 8575512 - Annapolis, MD 32 mi46 min NW 1 G 1.9 68°F 71°F1014 hPa
TPLM2 - Thomas Point, MD 32 mi16 min ESE 4.1 G 4.1 69°F 70°F1015.3 hPa (-1.0)69°F
NCDV2 35 mi46 min Calm G 1 67°F 69°F1013.9 hPa
CPVM2 36 mi46 min 69°F 69°F
44062 - Gooses Reef, MD 38 mi28 min ESE 3.9 G 3.9 69°F 70°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 38 mi46 min E 2.9 G 2.9 68°F 1014.5 hPa
FSNM2 38 mi46 min E 4.1 G 4.1 68°F 1014.3 hPa
BLTM2 - 8574680 - Baltimore, MD 39 mi46 min ESE 2.9 G 4.1 68°F 74°F1014.2 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 46 mi46 min ESE 4.1 G 5.1 1014.9 hPa
SLIM2 - 8577330 - Solomons Island, MD 47 mi46 min ENE 2.9 G 2.9 69°F 71°F1014.2 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA2 mi24 minN 02.50 miLight Drizzle Fog/Mist68°F66°F96%1014.7 hPa
Camp Springs / Andrews Air Force Base, MD9 mi20 minN 05.00 miFog/Mist67°F67°F100%1014.7 hPa
Fort Belvoir, VA10 mi20 minN 04.00 miLight Drizzle Fog/Mist68°F66°F96%1014.8 hPa
College Park Airport, MD12 mi21 minN 04.00 miOvercast66°F64°F93%1014.6 hPa
Fort Meade / Tipton, MD23 mi21 minN 01.25 miOvercast64°F64°F100%1015.6 hPa
Gaithersburg - Montgomery County Airport, MD24 mi20 minWNW 34.00 miFog/Mist65°F64°F97%1016.6 hPa
Washington/Dulles International Airport, DC, VA24 mi24 minWNW 510.00 miOvercast66°F64°F93%1014.9 hPa

Link to 5 minute data for KDCA

Wind History from DCA (wind in knots)
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Last 24hrN4N7N6NE7N7NE7NE5N7NE4N4N4NW8N7NE3N4N4N6NW3N5N4CalmN4CalmCalm
1 day agoSW3S5S4S5S7S5S7S8S5S7S6S6S9CalmCalmNE3NE6NE6E3S9SE6S5CalmN3
2 days agoCalmS3CalmCalmSE3N3N4N4NW3CalmS9S4S5S9SW5S5SW4SW3S6S4S4S3SW3Calm

Tide / Current Tables for Bellevue, D.C.
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Bellevue
Click for Map
Sun -- 02:37 AM EDT     Moonset
Sun -- 05:32 AM EDT     3.21 feet High Tide
Sun -- 07:00 AM EDT     Sunrise
Sun -- 12:25 PM EDT     0.37 feet Low Tide
Sun -- 05:20 PM EDT     Moonrise
Sun -- 06:07 PM EDT     2.97 feet High Tide
Sun -- 06:56 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.50.91.62.32.83.23.22.82.41.81.30.80.40.50.91.62.32.732.82.31.81.30.8

Tide / Current Tables for Benning Bridge, D.C.
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Benning Bridge
Click for Map
Sun -- 02:36 AM EDT     Moonset
Sun -- 05:47 AM EDT     3.34 feet High Tide
Sun -- 07:00 AM EDT     Sunrise
Sun -- 12:39 PM EDT     0.39 feet Low Tide
Sun -- 05:20 PM EDT     Moonrise
Sun -- 06:22 PM EDT     3.09 feet High Tide
Sun -- 06:56 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.50.81.52.22.83.23.33.12.621.510.50.40.81.52.22.73.132.621.41

Weather Map
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wmap_A
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
Ground Weather Radar Station Sterling, VA
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