Sunday, December17, 2017 L-36.com


Marine Weather and Tides
Arlington, VA

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 7:19AMSunset 4:49PM Sunday December 17, 2017 1:21 AM EST (06:21 UTC) Moonrise 6:32AMMoonset 4:43PM Illumination 1% Phase: Waning Crescent; Moon at 28 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- 1232 Am Est Sun Dec 17 2017
Overnight..W winds around 5 kt. Waves flat.
Sun..SE winds around 5 kt. Waves 1 ft or less.
Sun night..W winds around 5 kt. Waves 1 ft or less.
Mon..SW winds around 5 kt. Waves 1 ft.
Mon night..SW winds 5 kt. Waves less than 1 ft.
Tue..SW winds 5 to 10 kt. Waves 1 ft.
Tue night..W winds 5 kt. Waves less than 1 ft.
Wed..N winds around 5 kt. Waves 1 ft.
Thu..SE winds around 5 kt. Waves 1 ft. A chance of rain or freezing rain through the night.
ANZ500 1232 Am Est Sun Dec 17 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will remain south of the waters through Sunday. A backdoor cold front will approach from the north overnight, then return north as a warm front Sunday night. High pressure will influence the weather Tuesday before a cold front crosses Tuesday night. A small craft advisory is possible Tuesday night into Wednesday.

7 Day Forecast for Marine Location Near Arlington, VA
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location: 38.87, -77.06     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 170100
afdlwx
area forecast discussion
national weather service baltimore md washington dc
800 pm est Sat dec 16 2017

Synopsis
Weak backdoor front will slip south into the area late tonight
and Sunday. A weak upper level disturbance will cross the area
Sunday night. A warm front will lift north across the region
Monday. A cold front will drop south across the region Tuesday
night. High pressure will dominate Wednesday and Thursday.

Near term until 6 am Sunday morning
Forecast looks on track, so made no significant changes. Just
nudged to current observations, with traditional radiational
cooling spots cooling off a bit quicker this evening. Otherwise,
mid and high clouds come in after midnight likely causing
temperatures to level off. A weak backdoor front was dropping
south of the ny pa border as of early this evening, but with no
precipitation associated with it.

Previous discussion...

high pressure dominates at present, centered to the south, but
a cold front is slowly slipping toward us from the north. The
front will drop into the region late tonight, but with limited
if any sensible weather impact. High pressure will be the true
dominating factor in the weather tonight, with radiational
cooling allowing temps to drop back below freezing in most
areas. Winds will lighten quickly after sunset.

Short term 6 am Sunday morning through Monday night
Backdoor front stalls out in the area Sunday before essentially
dissipating. Thus, temps on Sunday, while starting chilly,
should not be significantly different from today. However,
clouds will be increasing ahead of a weakening shortwave which
is currently over western texas. The clouds will move in, but
the rain will be falling apart as the shortwave rides over the
top of a ridge to our south and forcing falls apart. Temps will
be marginal, so will have to look for potential mixed precip at
elevation and at night, mainly along the fringes of the cwa
(allgheny front and mason-dixon line), but right now it looks
like impacts will be minimal. (730 pm update... Added a slight
chance of freezing drizzle for the allegheny front north of
pendleton county WV given temps of 29-32 f and shallow
moisture).

Warm front lifts north Monday with temps rising into the 50s
most areas. Upslope showers may linger along allegheny front,
but most areas dry. Staying mild at night with lows above
freezing most spots.

Long term Tuesday through Saturday
Split upper level flow will be in place during the middle of
the week. Tuesday will likely be mild (50s to perhaps lower 60s)
if not a bit cloudy in between northern and southern stream
systems with a light southwest surface flow. Trough axis from
northern stream system will drop through the area by Tuesday
night, although it will be dry outside of a little upslope snow.

Wednesday could be breezy in the wake of the trough, and
temperatures will return closer to normal.

The 12z model suite is in a bit better agreement with keeping a
southern stream low pressure system suppressed to the south
(i.E., carolinas) Wednesday afternoon and night. With that said,
forecast QPF is close enough to central va that it will bear
watching since precipitation could take wintry form.

High pressure slides across the great lakes toward new england
Thursday into Friday. The high eventually becomes in a position
favorable for cold air damming, although at this time there
aren't any strong indications of clouds or precipitation, as a
subtropical ridge encroaches on the southeastern states. This is
subject to change pending any weak waves. Temperatures should
remain fairly close to normal.

The next upper trough will push toward the east coast Friday
into Saturday. This is the time period where guidance begins to
deviate the most since the northern and southern streams could
eventually phase. Meanwhile the subtropical ridge could attempt
to stay dominant to the southeast. Precipitation chances will be
increasing since the associated cold front could be slow
moving. Precipitation types could eventually become tricky over
parts of the area depending where the baroclinic zone settles
and if additional energy rides along it. Overall not looking at
any major blasts of cold air within the forecast period though.

Aviation 01z Sunday through Thursday
Vfr likely through Monday night. Main concern is isolated
showers late Sunday Sunday night which may briefly drop cigs
and vis, mainly near northwest of mrb to mtn. Winds will stay
fairly light through Monday night.

Vfr is anticipated for Tuesday through Thursday at the moment,
although a low pressure system won't be too far away to the
south on Wednesday that is worth watching. Northwest winds could
gust to 25 kt on Wednesday behind a low pressure trough.

Marine
Winds have subsided, so dropped the sca. Light winds are
anticipated through Monday night.

Southwest winds will begin increasing Tuesday. A trough of low
pressure will cross Tuesday night, with winds becoming
northwesterly and increasing further. A small craft advisory
will be possible through Wednesday. Lighter winds can be
expected Wednesday night into Thursday as high pressure builds
into the area.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... None.

Synopsis... Rcm
near term... Rcm dhof
short term... Rcm dhof
long term... Ads
aviation... Ads rcm dhof
marine... Ads rcm dhof


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 2 mi52 min Calm G 1 34°F 39°F1023.3 hPa
BSLM2 - Chesapeake Bay, MD 20 mi112 min Calm 27°F 1023 hPa26°F
APAM2 - 8575512 - Annapolis, MD 32 mi52 min 35°F 1022.5 hPa
TPLM2 - Thomas Point, MD 33 mi82 min W 4.1 G 5.1 39°F 44°F
FSNM2 37 mi52 min W 6 G 7 38°F 1022.1 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 37 mi52 min W 5.1 G 5.1 37°F 1022.9 hPa
CPVM2 37 mi52 min 40°F 28°F
BLTM2 - 8574680 - Baltimore, MD 37 mi52 min WSW 1.9 G 2.9 35°F 45°F1022.4 hPa
NCDV2 38 mi52 min Calm G 1.9 35°F 39°F1022.2 hPa
44062 - Gooses Reef, MD 40 mi42 min WSW 7.8 G 9.7 43°F 1023.5 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 48 mi52 min W 16 G 18 41°F 1023.4 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 49 mi52 min ESE 2.9 G 4.1 32°F 37°F1023 hPa

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA2 mi30 minN 010.00 miA Few Clouds35°F28°F76%1023.1 hPa
Camp Springs / Andrews Air Force Base, MD10 mi26 minN 010.00 miFair29°F22°F75%1023.3 hPa
College Park Airport, MD11 mi36 minN 010.00 miFair26°F23°F90%1023 hPa
Fort Belvoir, VA12 mi26 minN 010.00 miFair26°F22°F85%1023.4 hPa
Gaithersburg - Montgomery County Airport, MD21 mi26 minN 010.00 miFair27°F23°F85%1025.6 hPa
Washington/Dulles International Airport, DC, VA22 mi30 minN 010.00 miFair26°F21°F84%1022.7 hPa
Fort Meade / Tipton, MD22 mi37 minN 010.00 miFair25°F23°F93%1024 hPa

Wind History from DCA (wind in knots)
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Last 24hrS8SW6SW8SW5SW7SW5SW6SW7SW11S12SW14
G21
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S10SW6S6S5S3S4SW3CalmCalm
1 day agoE8E6E4E6E5E5E6E5E3E4NE5N5NW7N3CalmN5W4W5SW4SW4S5S6S5S7
2 days agoS10S9S10SW8SW7SW6W5W11
G16
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N15N11N12N11N12N9N11N12N10NE9NE6NE7

Tide / Current Tables for Washington, Potomac River, D.C.
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Washington
Click for Map
Sun -- 02:07 AM EST     -0.24 feet Low Tide
Sun -- 06:31 AM EST     Moonrise
Sun -- 07:20 AM EST     Sunrise
Sun -- 07:24 AM EST     2.50 feet High Tide
Sun -- 02:03 PM EST     -0.17 feet Low Tide
Sun -- 04:43 PM EST     Moonset
Sun -- 04:47 PM EST     Sunset
Sun -- 07:37 PM EST     2.82 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.50-0.2-00.71.52.12.52.421.40.80.30-0.20.10.81.62.32.72.82.51.91.3

Tide / Current Tables for Bladensburg, Anacostia River, Maryland
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Bladensburg
Click for Map
Sun -- 02:32 AM EST     -0.27 feet Low Tide
Sun -- 06:31 AM EST     Moonrise
Sun -- 07:20 AM EST     Sunrise
Sun -- 07:55 AM EST     2.65 feet High Tide
Sun -- 02:28 PM EST     -0.19 feet Low Tide
Sun -- 04:42 PM EST     Moonset
Sun -- 04:47 PM EST     Sunset
Sun -- 08:08 PM EST     2.99 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.70.2-0.2-0.20.31.21.92.52.62.41.81.10.60.1-0.1-0.10.41.32.22.732.82.31.7

Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Mid-Atlantic    EDIT
Geos

Wind Forecast for Baltimore, MD/Washington (1,6,7,8)
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Ground Weather Radar Station Sterling, VA
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weather_mapweather_map weather_map

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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.