Thursday, July29, 2021
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Marine Weather and Tides
Glassmanor, MD

Version 3.4
NOTICE
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.

Sunrise 6:05AMSunset 8:23PM Thursday July 29, 2021 10:58 AM EDT (14:58 UTC) Moonrise 10:46PMMoonset 10:48AM Illumination 73% Phase: Waning Gibbous; Moon at 20 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- 1035 Am Edt Thu Jul 29 2021
.small craft advisory in effect from Friday morning through Friday afternoon...
Rest of today..S winds 5 to 10 kt. Waves 1 ft. A chance of showers late this morning, then a chance of showers with a slight chance of tstms this afternoon.
Tonight..SW winds 5 kt. Waves less than 1 ft. A chance of showers and tstms.
Fri..NW winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft.
Fri night..N winds 5 to 10 kt. Gusts up to 20 kt in the evening. Waves 1 ft.
Sat..NW winds 5 kt. Waves less than 1 ft.
Sat night..S winds around 5 kt. Waves 1 ft. A chance of showers.
Sun..W winds around 5 kt. Waves 1 ft. Scattered showers. A chance of tstms through the night.
Mon..NE winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 1035 Am Edt Thu Jul 29 2021
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A strong cold front will approach the area today before crossing the region late tonight. A second, weaker front will cross the region Friday night. High pressure will build in for Saturday before another area of low pressure possibly affects the region Sunday. Small craft advisories may be needed Friday night.


7 Day Forecast for Marine Location Near Glassmanor, MD
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location: 38.83, -77     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 291434 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1034 AM EDT Thu Jul 29 2021

SYNOPSIS. A cold front will approach the area today into tonight. High pressure will build in for Friday into this weekend, bringing drier and cooler conditions. Another system may impact the area Sunday.

NEAR TERM /THROUGH TONIGHT/. Mid-morning update: Current radar imagery shows a decaying MCS over Ohio. Cloud debris is starting to stream into the area downstream of this decaying MCS, with the highest coverage of clouds currently over northern portions of the forecast area. Low clouds developed for a short time early this morning along the I-95 corridor, but are now in the process of burning off. Considerable questions still remain regarding the areal coverage of storms later this afternoon, but given the environment in place, storms that do form will be capable of producing damaging winds, large hail, and potentially even a tornado or two. We will continue to monitor incoming model guidance/trends in observational data over the coming hours and will update our forecast accordingly.

Previous discussion follows .

Latest analysis depicts a weak stationary front straddled northwest to southeast across the area. A stronger front and low pressure is located over the Great Lakes, with the low heading east and the front progressing southeast. Aloft, a weak shortwave is passing to the east with a second stronger shortwave over the Great Lakes. This is all embedded within a dominant northwest flow as a longwave trough remains to our northeast, and a ridge sits over the central Plains.

Showers early this morning associated with the departing shortwave should dissipate shortly. The clouds and increased moisture over the region have kept temps in the higher 60s to lower 70s. This relatively high starting point will give us a boost, but clouds moving in from the MCS to our northwest will start overspreading the area this morning. This MCS likely will greatly affect our severe weather threat today as the strong shortwave and cold front moves into the region. If the MCS impact is minimal, with cloud cover relatively thin and brief and minimal if any showers, then our odds of a significant severe weather outbreak will be quite high thanks to ample CAPE combined with the high shear moving overhead. However, if the MCS holds together more and we have extended cloud cover and more showers/weakening storms, the high CAPE component will be harder to come by, which could potentially significantly damper the severe weather potential. Will need to watch progress of the system closely. Right now, areas least likely to be affected by the morning MCS appear to be the Baltimore area and points north and east, where an enhanced risk of severe weather is now in place from the SPC. This risk tapers to slight and then marginal further south and west, where the MCS influence is likely to be more substantial. Highs likely reach the mid-upper 80s, perhaps with spotty 90s, with higher temps of course more likely to fuel stronger storms later today. Best timing for storms looks to be very late afternoon and evening across the metro, assuming the MCS doesn't disrupt CAPE too much.

Tonight, front doesn't actually move through until very late, so while shower/storm coverage will dwindle with loss of heating, some chance of showers and storms will linger until the front actually passes. Lows stay mild with the front not yet thru until very late, with readings mostly in the higher 60s to 70s.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/. First front clears the CWA early Friday morning, with gusty northwest flow taking hold. Initially, air mass temperature doesn't change, just the dew points, so it will be very warm but with lower humidity and a gusty northwest wind. Compressional heating on the downslope flow likely brings temps near 90 once again.

Second front drops south across the region Friday night. This will bring a cooler air mass with it, but otherwise no weather change of significance, with no moisture to work with and little forcing. Lows will drop into the 50s in many areas, with low- mid 60s in the rest of the area.

Saturday will be considerably cooler under Canadian high pressure, but with lighter winds. Dew points drop further, with readings potentially dropping into the upper 40s. This all will combine to create a decidedly un-summerlike last day of July.

Wave of low pressure starts to bring moisture back north Saturday night, with increasing clouds and a chance of showers late at night. Lows will stay mostly in the 60s thanks to the returning clouds.

LONG TERM /SUNDAY THROUGH WEDNESDAY/. Come Sunday, a shortwave trough will have ejected out of the Canadian Prairies and into the Great Lakes. At the surface, a cold front will move southeast across Ohio and Pennsylvania. The front may not pass through the FA until Sunday night, but given a southerly return flow and modest instability ahead of the front, cannot rule out showers and thunderstorms ahead of the front Sunday afternoon and evening. Both deterministic and ensemble guidance hint at a weak coastal low forming Sunday in North Carolina and moving northeast towards the lower Chesapeake Bay. There could be slightly greater coverage of precip across southern Maryland late Sunday if this area of low pressure develops.

Once the front clears the FA Sunday night, the front stalls near the North Carolina / Virginia border as it becomes parallel to the upper level flow. High pressure will build into the region Monday.

An H5 trough builds over the Ohio Valley late Monday and remains nearly stationary through midweek as multiple shortwaves round the base of the trough providing multiple opportunities for at least isolated/scattered precip. The broad trough could form into an upper- level closed low, as depicted by some guidance. Late Tuesday into Wednesday could be a time period of more widespread precip as an area of coastal low pressure forms and moves northeast towards the Mid Atlantic seaboard, though uncertainty remains on the track of this feature and if it will come to fruition.

AVIATION /14Z THURSDAY THROUGH MONDAY/. Current satellite imagery shows the IFR ceilings from earlier this morning along the I-95 corridor slowly starting to break up and lift. These clouds should continue to break up over the next few hours, leading to prevailing VFR conditions areawide by later this morning into this afternoon. High clouds are streaming in from the west, and thunderstorm are expected to break out across the area later this afternoon into this evening. While not all locations will see storms, eastern terminals will have the greatest chance at experiencing a storm. Any storms this afternoon could be very strong, with high winds and hail both possibilities. Thunderstorms will wind down this evening, giving way to VFR conditions overnight. VFR conditions are expected for both tomorrow and Saturday. Winds may gust to around 20 knots out of the northwest tomorrow afternoon. Lighter winds are expected on Saturday as high pressure builds toward the area from the Ohio Valley.

South/southwest winds ahead of the front Sunday with primarily VFR conditions. Can have brief MVFR restrictions in any showers or thunderstorms Sunday afternoon. VFR conditions Monday as high pressure builds in with the winds becoming northwest.

MARINE. Increasing southerly channeling today will result in SCA conditions by this afternoon, mainly over the bay. Strong to severe thunderstorms are possible later today into tonight, which may necessitate SMW's. Front pushes southeast early on Friday, with widespread SCA conditions on northwest flow in its wake. A second surge of SCA winds may occur Friday night as a second front passes. Winds relax Saturday through Saturday night under high pressure.

Winds remain below SCA levels at 10-15 knots out of the south/southwest Sunday before backing out of the northwest Monday.

TIDES/COASTAL FLOODING. Southerly flow ahead of an approaching cold front will result in some locations reaching action stage through tonight. Minor flooding is most likely to occur at the most sensitive sites, such as Annapolis. As the winds become northwest behind the front on Friday, the anomalies will decrease.

LWX WATCHES/WARNINGS/ADVISORIES. DC . None. MD . None. VA . None. WV . None. MARINE . Small Craft Advisory until 6 PM EDT this evening for ANZ531>533-539>541. Small Craft Advisory from 8 AM to 6 PM EDT Friday for ANZ530>533-535-536-538>542. Small Craft Advisory until 6 PM EDT Friday for ANZ534-543. Small Craft Advisory from 6 PM this evening to 6 PM EDT Friday for ANZ537.

SYNOPSIS . RCM NEAR TERM . RCM/KJP SHORT TERM . RCM LONG TERM . CPB AVIATION . RCM/KJP/CPB MARINE . RCM/CPB TIDES/COASTAL FLOODING . CPB


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 3 mi58 min S 6 G 7 79°F 84°F1015.5 hPa (+0.0)
BSLM2 - Chesapeake Bay, MD 16 mi88 min W 1.9 74°F 1015 hPa72°F
APAM2 - 8575512 - Annapolis, MD 30 mi58 min ESE 6 G 8 85°F 84°F1014.7 hPa (-0.5)
TPLM2 - Thomas Point, MD 30 mi58 min SSE 15 G 16 78°F 81°F1016 hPa (-0.4)77°F
44063 - Annapolis 31 mi52 min S 9.7 G 14 77°F 82°F1 ft1016.1 hPa
CPVM2 34 mi58 min 79°F 75°F
NCDV2 35 mi58 min WSW 4.1 G 6 79°F 85°F1015 hPa (-0.0)
44062 - Gooses Reef, MD 36 mi52 min SSW 12 G 16 80°F 3 ft1015.9 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 37 mi58 min SW 5.1 G 8.9 79°F 1014.9 hPa (-0.6)
FSNM2 37 mi58 min SSW 4.1 G 7 79°F 1015 hPa (-0.4)
BLTM2 - 8574680 - Baltimore, MD 38 mi58 min WSW 4.1 G 7 80°F 84°F1014.6 hPa (-0.6)
COVM2 - 8577018 - Cove Point LNG Pier, MD 44 mi58 min SE 12 G 14 79°F 1015.3 hPa (-0.0)
SLIM2 - 8577330 - Solomons Island, MD 46 mi58 min S 8.9 G 11 81°F 83°F1015 hPa (-0.5)
TCBM2 - 8573364 - Tolchester Beach, MD 48 mi58 min SSW 5.1 G 7 79°F 81°F1015.3 hPa (-0.9)

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA3 mi66 minS 710.00 miMostly Cloudy81°F73°F77%1015.7 hPa
Camp Springs / Andrews Air Force Base, MD7 mi62 minWSW 510.00 miMostly Cloudy79°F71°F79%1015.7 hPa
College Park Airport, MD11 mi83 minSSE 410.00 miMostly Cloudy79°F71°F76%1015.2 hPa
Fort Belvoir, VA12 mi62 minS 310.00 miA Few Clouds79°F73°F81%1015.8 hPa
Fort Meade / Tipton, MD22 mi63 minWSW 510.00 miMostly Cloudy77°F72°F83%1016.3 hPa

Link to 5 minute data for KDCA

Wind History from DCA (wind in knots)
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Last 24hrN7N11N8NW5
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4CalmN6E10E10E7SE3SE4NW6SW13S6S3SW4SW4Calm3SE3SE4SW3S7
1 day agoCalmSE3S5S4NE45N8NW6NW10NW6NW6CalmS3CalmCalmW4SW4N3CalmN8N5N6NE4N6
2 days agoN5NE45E4N5Calm3E11SE10--S5W3W4CalmCalmCalmNW3SW3S4CalmS5CalmS4S6

Tide / Current Tables for Reagan National Airport, Washington, D.C.
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Reagan National Airport
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Thu -- 12:52 AM EDT     3.34 feet High Tide
Thu -- 06:06 AM EDT     Sunrise
Thu -- 07:33 AM EDT     0.42 feet Low Tide
Thu -- 11:49 AM EDT     Moonset
Thu -- 01:11 PM EDT     3.21 feet High Tide
Thu -- 07:47 PM EDT     0.30 feet Low Tide
Thu -- 08:21 PM EDT     Sunset
Thu -- 11:46 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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3.23.33.12.51.91.30.80.50.50.91.72.533.23.12.61.91.30.80.40.30.61.42.2

Tide / Current Tables for Key Bridge, D.C.
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Key Bridge
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Thu -- 01:01 AM EDT     3.21 feet High Tide
Thu -- 06:06 AM EDT     Sunrise
Thu -- 07:41 AM EDT     0.40 feet Low Tide
Thu -- 11:49 AM EDT     Moonset
Thu -- 01:20 PM EDT     3.09 feet High Tide
Thu -- 07:55 PM EDT     0.28 feet Low Tide
Thu -- 08:22 PM EDT     Sunset
Thu -- 11:46 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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33.232.51.91.30.80.50.40.81.52.32.83.132.61.91.30.80.40.30.51.22

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