Friday, September25, 2020
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Marine Weather and Tides
Mount Vernon, 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 6:58AMSunset 7:01PM Friday September 25, 2020 7:51 PM EDT (23:51 UTC) Moonrise 2:59PMMoonset 12:00AM Illumination 63% Phase: Waxing Gibbous; Moon at 9 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- 736 Pm Edt Fri Sep 25 2020
Tonight..SE winds 5 kt. Waves less than 1 ft. Showers. Areas of fog. Vsby 1 to 3 nm.
Sat..SE winds 5 kt. Waves less than 1 ft. A chance of showers. Areas of fog. Vsby 1 to 3 nm.
Sat night..SE winds around 5 kt. Waves 1 ft.
Sun..S winds around 5 kt. Waves 1 ft.
Sun night..S winds 5 kt. Waves less than 1 ft.
Mon..S winds around 5 kt. Waves 1 ft.
Mon night..S winds around 5 kt. Waves 1 ft. A chance of showers.
Tue..SW winds 5 kt. Waves less than 1 ft. A chance of tstms. A chance of showers.
Wed..W winds around 5 kt. Waves 1 ft. A chance of showers. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 736 Pm Edt Fri Sep 25 2020
Synopsis for the tidal potomac and md portion of the chesapeake bay.. The remnants of beta will likely pass to the south while weakening tonight into Saturday. A pair of cold fronts are expected to approach from the great lakes and ohio river valley late in the weekend into early next week. Small craft advisories may be needed for portions of the waters Monday through Tuesday.


7 Day Forecast for Marine Location Near Mount Vernon, VA
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location: 38.68, -77.1     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 251923 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 323 PM EDT Fri Sep 25 2020

SYNOPSIS. Remnants of Beta making their way toward the Carolinas as high pressure sits over the western Atlantic. As the system passes to our south and off the Carolina coast through Saturday morning, high pressure will build back over the region for the second half of the weekend with drier and warmer conditions returning. A series of cold fronts will impact the region during the early and middle portions of next week bringing unsettled weather.

NEAR TERM /THROUGH TONIGHT/. Satellite imagery this afternoon showing some breaks in the mid to high cloud decks this afternoon over eastern West Virginia and northern/western Maryland, allowing the sun to peak through. Unfortunately, clouds associated with the remnants of Beta to our south are quickly moving back into the area from southwestern Virginia and central West Virginia. Regional radar mosaic shows light shower activity moving northeastward through central Virginia at this hour, with some light rain making its way in to the D.C. metro the last couple of hours. Temperatures currently are in the middle 60s to middle 70s from south to north across the CWA, a reversal of what we typically see, but we have the clouds and rain showers to thank for that. Temperatures will rise a few more degrees this afternoon, but with clouds rolling back in, it'll put a lid on that upward progression.

Tonight, the core remnants of Beta will stay mostly to our south and weaken as they track through the Carolinas. Despite this southerly track, light rain will creep northward toward the metros and east of the Blue Ridge Mountains as some hi-res guidance favors. Low clouds, areas of fog, and drizzle will be expected area wide as low level moisture remains a plenty and surface winds turn more onshore. Temperatures tonight will hold in the upper 50s to middle 60s, fairly mild for late September.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/. Lingering clouds, fog, and drizzle will attempt to hold on strong Saturday morning, and perhaps into the early afternoon hours east of the Blue Ridge as weak onshore flow persists. High pressure will attempt to build back into the region the second half of Saturday, helping to erode the cloud cover during the mid to late afternoon hours. Skeptical on how quickly this happens given the onshore flow and ample low level moisture. With that being said, will hold high temperatures in the low to middle 70s, which may be a little generous if the clouds hang around for much of the day.

We'll keep dry conditions in the forecast Saturday night as the high builds overhead, but with dewpoints remaining elevated and saturation from the prior rains, patchy fog seems like a good bet into Sunday morning. Temperatures Saturday night once again in the middle 50s to middle 60s. Warm and dry conditions expected Sunday as winds turn southerly, highs extending into the upper 70s to low 80s. Dewpoints well into the 60s to near 70 will also deliver decent humidity for late September. Warm once again Sunday night under mostly cloudy skies as we warm advect out ahead of a digging trough dropping down from the Upper Midwest. Lows Sunday night in the upper 50s to middle 60s.

LONG TERM /MONDAY THROUGH FRIDAY/. Rain chances gradually increase Monday through Tuesday night as a persistent southerly flow develops with high pressure over the western Atlantic and a modest trough of low pressure over the Midwest U.S. and Ohio Valley. Pieces of energy will move into the region from southwest to northeast during this time, creating showers and perhaps a thunderstorm or two later Monday through Tuesday.

Although timing on the heavier precipitation still seems to vary Tuesday into Tuesday night, it looks like Wednesday could still have lingering showers or a thunderstorm around in the morning. Drier and cooler air should fill into the region later in the day Wednesday and Thursday. Additional weaker energy could bring a chance for upslope showers in the Potomac Highlands Thursday afternoon. For now, most areas should be dry and cooler.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/. Light rain in association with the remnants of Beta will extend northward across the terminals through tonight. While the rain will remain on the light side, am expecting restrictions in the IFR to LIFR range as CIGs drop given ample low level moisture under a light south southeasterly flow. Areas of fog and drizzle will also yield reduced visibilities into Saturday morning as well. As the system exits off the coast and high pressure starts to build back into the region, conditions should improve to MVFR Saturday afternoon, potentially VFR everywhere by days end under a light southeasterly breeze.

Dry conditions Saturday night under high pressure, thus winds will remain light to calm. High dewpoints and recent rains will allow for patchy fog to deliver restrictions to the terminals again into early Sunday morning. Light southerly winds and dry conditions expected Sunday and Sunday night, with VFR prevailing.

VFR conditions for the most part Monday into early Tuesday. Any modest showers Monday night through Tuesday night could briefly bring MVFR conditions at any of the terminals. Throughout the day Wednesday, MVFR conditions should become VFR conditions. VFR conditions possible Thursday as most areas will be cooler and drier.

MARINE. Sub SCA conditions expected over the marine district this weekend as the remnants of Beta pass to the south and high pressure builds overhead through Sunday night. Winds will remain light and favor a south southeast trajectory during this time.

Southerly winds will increase Monday ahead of an approaching trough and cold front, but look to remain below SCA thresholds through early Tuesday. Thereafter, the gradient will tighten ahead of said cold front Tuesday afternoon and evening. SCA gusts may linger behind the frontal passage on Wednesday, necessitating the need for an Advisory during this period.

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.

Technicians from the National Weather Service Radar Operations Center will arrive in Sterling on Saturday, September 26, to diagnose the failure. At that time, they will determine the full scope of the failure, and work with WFO Sterling electronics program staff in taking subsequent maintenance actions. Action and diagnosis includes repairing the gear box and assessing the health of the bull- gear.

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).

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

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


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 14 mi51 min Calm G 0 66°F 69°F1019.3 hPa (-0.0)
BSLM2 - Chesapeake Bay, MD 22 mi141 min Calm 1018 hPa
NCDV2 25 mi51 min E 7 G 8.9 68°F 69°F1018 hPa (-0.5)
44062 - Gooses Reef, MD 37 mi33 min SSE 7.8 G 9.7 67°F 70°F
TPLM2 - Thomas Point, MD 38 mi51 min ESE 8 G 8.9 67°F 70°F1020 hPa (-0.4)64°F
APAM2 - 8575512 - Annapolis, MD 39 mi51 min SSE 1 G 4.1 68°F 71°F1018.7 hPa (+0.0)
COVM2 - 8577018 - Cove Point LNG Pier, MD 42 mi51 min SE 11 G 12 1019.5 hPa (+0.0)
SLIM2 - 8577330 - Solomons Island, MD 42 mi51 min SSE 6 G 8 67°F 71°F1018.7 hPa (+0.0)
CPVM2 44 mi51 min 68°F 63°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 48 mi51 min SSW 2.9 G 2.9 67°F 1019.2 hPa (+0.0)
FSNM2 48 mi51 min SSW 1.9 G 2.9 67°F 1018.9 hPa (+0.0)
PPTM2 - 8578240 - Piney Point, MD 48 mi51 min SE 8.9 G 9.9
BLTM2 - 8574680 - Baltimore, MD 49 mi51 min WSW 1.9 G 2.9 67°F 75°F1018.7 hPa (+0.0)

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA5 mi55 minN 010.00 miFair65°F62°F94%1019.6 hPa
Washington/Reagan National Airport, DC, VA13 mi59 minNE 310.00 miLight Rain66°F62°F87%1019.3 hPa
Camp Springs / Andrews Air Force Base, MD16 mi55 minE 310.00 miA Few Clouds64°F62°F94%1019.6 hPa
Quantico Marine Corps Airfield - Turner Field, VA16 mi55 minE 310.00 miMostly Cloudy68°F63°F84%1019.2 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA22 mi55 minN 010.00 miMostly Cloudy64°F62°F93%1019.7 hPa
College Park Airport, MD23 mi56 minN 07.00 miPartly Cloudy63°F61°F93%1019.3 hPa

Link to 5 minute data for KDAA

Wind History from DAA (wind in knots)
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Last 24hrCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS4CalmS4S3S4CalmCalmCalmCalm
1 day agoCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS5S3CalmS3S3CalmCalm
2 days agoCalmCalmCalmCalmCalmCalmCalmCalmCalmSE3CalmCalmCalmCalmNW8NW7
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Tide / Current Tables for Marshall Hall, Maryland
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Marshall Hall
Click for Map
Fri -- 12:36 AM EDT     Moonset
Fri -- 03:02 AM EDT     2.67 feet High Tide
Fri -- 06:59 AM EDT     Sunrise
Fri -- 09:44 AM EDT     0.34 feet Low Tide
Fri -- 03:47 PM EDT     2.31 feet High Tide
Fri -- 03:59 PM EDT     Moonrise
Fri -- 06:59 PM EDT     Sunset
Fri -- 09:44 PM EDT     0.39 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.82.32.62.72.52.11.71.20.80.50.30.61.11.622.22.32.11.61.10.70.50.40.6

Tide / Current Tables for High Point, Occoquan Bay, Virginia
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High Point
Click for Map
Fri -- 12:36 AM EDT     Moonset
Fri -- 02:01 AM EDT     1.83 feet High Tide
Fri -- 06:59 AM EDT     Sunrise
Fri -- 09:06 AM EDT     0.24 feet Low Tide
Fri -- 02:47 PM EDT     1.59 feet High Tide
Fri -- 03:59 PM EDT     Moonrise
Fri -- 07:00 PM EDT     Sunset
Fri -- 09:06 PM EDT     0.28 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.51.81.81.71.51.20.90.60.40.20.30.711.31.51.61.41.10.80.60.40.30.40.7

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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