Wednesday, November22, 2017 L-36.com


Marine Weather and Tides
National Harbor, MD

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 6:58AMSunset 4:51PM Wednesday November 22, 2017 6:08 AM EST (11:08 UTC) Moonrise 10:16AMMoonset 8:20PM Illumination 14% Phase: Waxing Crescent; Moon at 4 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- 433 Am Est Wed Nov 22 2017
.small craft advisory in effect through this afternoon...
Rest of the overnight..W winds 5 kt. Waves less than 1 ft. Rain likely.
Today..NW winds 10 to 15 kt. Gusts up to 20 kt... Increasing to 25 kt in the afternoon. Waves 1 ft.
Tonight..NW winds 5 to 10 kt. Waves 1 ft.
Thu..W winds 5 kt. Waves less than 1 ft.
Thu night..W winds around 5 kt. Waves 1 ft.
Fri..S winds around 5 kt. Waves 1 ft.
Fri night..S winds around 5 kt. Waves 1 ft.
Sat..NW winds around 5 kt. Waves 1 ft.
Sun..NW winds 5 to 10 kt. Waves 1 ft.
ANZ500 433 Am Est Wed Nov 22 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front will pass through early this morning and high pressure will return for later today through early Friday. Another cold front will approach late Friday into Saturday before passing through Saturday night. High pressure will return for Sunday and Monday. A small craft advisory may be needed for the waters late Saturday and Sunday.

7 Day Forecast for Marine Location Near National Harbor, MD
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location: 38.8, -77.03     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 220845
afdlwx
area forecast discussion
national weather service baltimore md washington dc
345 am est Wed nov 22 2017

Synopsis
A cold front will pass through the area early this morning and
high pressure will build overhead later today through Friday.

High pressure will move offshore Friday night and a cold front
will pass through late Saturday into Saturday night. High
pressure will return for early next week.

Near term through tonight
A cold front is located over southwest pennsylvania into west
virginia as of 3 am this morning. The cold front will pass
through our area over the next few hours from west to east. At
the same time... Southern stream moisture is advecting north into
our area. The southern stream moisture is most likely to make
it into areas near and east of interstate 95. Therefore... A
period of rain is most likely across these areas early this
morning with the frontal passage.

The front will move off to the south and east by mid-morning
and high pressure will approach from the midwest and great
lakes. A potent shortwave will pass by to our north during this
time... But with most of the dynamics remaining to the north it
should not have an impact on our weather. Therefore... Increasing
sunshine and gusty northwest winds are expected ahead of the
building high. MAX temps are a little tricky to forecast since
there will be cold advection behind the cold front... But that
will be offset by increasing sunshine and mixing along with a
downsloping flow. Did tweak the hourly trend in temps a little
away from the typical diurnal trend. Feel that MAX temps will
occur late this morning to around noon before holding steady and
even falling during the middle afternoon hours. MAX temps are
most likely to range from the lower to middle 30s along the
ridge tops of the allegheny highlands... To the mid and upper 40s
for most of northern maryland into the shenandoah valley... To
the middle 50s near washington and baltimore... To the upper 50s
and even near 60 in central virginia into southern maryland.

Also of note... There will be a period of snow showers through
mid-morning for locations along west of the allegheny front.

Moisture will be limited... But an upslope component along with a
higher subsidence inversion will cause some accumulation above
2000 feet. Accumulations around an inch or less are most likely
before snow showers taper off by late morning.

High pressure will build overhead tonight and winds will
decrease around sunset for most areas. Winds will become light
overnight and with dry air and mainly clear skies this will
provide a great setup for radiational cooling. Min temps will
range from the upper teens and lower 20s in sheltered valleys
and rural areas west of the blue ridge mountains... To the mid
and upper 20s across most other locations to the lower and
middle 30s in downtown washington and baltimore.

Short term Thursday through Friday night
High pressure will remain overhead thanksgiving day and
thanksgiving night... Bringing dry and chilly conditions along
with mainly clear skies. High pressure will shift to the east
coast Friday and move offshore Friday night. A southerly flow
will return during this time. MAX temps will be a bit warmer
Friday... But still near or even slightly below climo. More dry
conditions are expected during this time. Friday night will be
seasonably chilly... But not as cold as thanksgiving night.

Long term Saturday through Tuesday
Long term period starts out Saturday with a ridge west trough
east pattern, but by the end it completely flips, with trough
west ridge east by Tuesday. At the surface, this will translate
into a cold frontal passage on Saturday, followed by high
pressure progressing slowly east across the region Sunday
through Tuesday. In many ways, surface features Saturday will
mirror what is happening tonight. As with tonight, one thing to
watch Saturday is a coastal low pressure which will also be
moving northeast along the carolina coast. Should this system
end up a bit further northwest, it could spread some rain into
the region, but unlike tonight, most guidance keeps this system
well to the southeast, completely separated from the
approaching northern stream shortwave and surface cold front.

This means that right now, we think the cold frontal passage
should be dry for most of the cwa. We will likely moderate
thanks to southwesterly flow just ahead of the cold front,
resulting in Saturday being rather like yesterday was... Breezy
with some clouds and temps well into the 50s, perhaps even low
60s. Along and behind the front, some showers will affect the
northwestern and western portions of the cwa, primarily the
higher terrain, and much like today, these will change to snow
showers behind the front, which in this case will occur on
Saturday night. However, the system is fast moving, so do not
expect significant accumulations even in the favored upslope
regions. Chilly and breezy but mostly dry Sunday with high
pressure starting to build in... Any lingering upslope snow
showers will be winding down. Most areas will not get out of
the 40s. On Monday, high pressure crosses the region, but temps
remain chilly with the trough just starting to exit aloft, so
only slight warming. By Tuesday, however, southwest flow will
start again in earnest as the high slides off the coast, and
moderation will become more apparent, with highs returning to
the 50s most likely.

Aviation 07z Wednesday through Sunday
A period of rain is possible across the eastern
terminals... Kdca... Kbwi and kmtn through about 12z. Brief MVFR
conditions are possible during this time... But a majority of the
time should beVFR.

Gusty northwest winds will develop behind a cold front between
13z and 15z. The gusty winds will continue through the afternoon
with frequent gusts around 20 to 25 knots with a few gusts up
to 30 knots. The winds will diminish around sunset. High
pressure will build over the terminals tonight through Thursday
night... BringingVFR conditions and lighter winds. Winds will
turn to the south later Friday and Friday night as high pressure
shifts offshore.

Saturday and Sunday look mainlyVFR for now, with a gusty wind
(perhaps up to 30 knots at times) starting southwest, then
switching to northwest behind a cold front later Saturday. These
winds likely persist Sunday. A coastal low will be sliding
northeast off the coast on Saturday, but right now effects look
minimal to non-existent. If it ends up closer, a period of sub-
vfr would be possible on Saturday due to rain, but odds of this
look low right now.

Marine
A cold front will pass through the waters early this morning.

High pressure will approach from the north and west today before
building overhead tonight through thanksgiving night. Gusty
northwest winds are expected behind the cold front today. Gusts
of 20 to 30 knots are most likely. An SCA is in effect for the
waters. The winds will gradually diminish tonight... But an sca
is still in effect for most of the bay and lower tidal potomac
river. Winds will continue to diminish for thanksgiving as the
high settles overhead.

High pressure will shift offshore Friday through Friday night
and a southerly flow will return... But winds should remain below
sca criteria for most of the time since the gradient will be
weak.

Cold front crossing the area Saturday will bring southwest
winds which then switch northwest by Saturday night, lingering
Sunday. These are likely to reach SCA criteria and could be near
gale, but confidence is not high on this.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory from 6 am this morning to 6 am est
Thursday for anz531>534-537-539>541-543.

Small craft advisory from 6 am this morning to 6 pm est this
evening for anz530-535-536-538-542.

Synopsis... Bjl
near term... Bjl
short term... Bjl
long term... Rcm
aviation... Bjl rcm
marine... Bjl rcm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 5 mi51 min S 1.9 G 2.9 52°F 48°F1013.8 hPa
BSLM2 - Chesapeake Bay, MD 17 mi99 min SSE 4.1 49°F 1013 hPa48°F
APAM2 - 8575512 - Annapolis, MD 32 mi51 min 53°F 1012.3 hPa
TPLM2 - Thomas Point, MD 32 mi69 min S 7 G 7 54°F 53°F
NCDV2 33 mi57 min NW 1 G 4.1 52°F 50°F1012.4 hPa
44063 - Annapolis 33 mi39 min SSW 3.9 G 3.9 53°F 1012.2 hPa
44062 - Gooses Reef, MD 37 mi39 min S 9.7 G 9.7 54°F 1013.9 hPa
CPVM2 37 mi51 min 54°F 50°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 39 mi51 min NW 6 G 6 52°F 1012.7 hPa
BLTM2 - 8574680 - Baltimore, MD 40 mi57 min Calm G 1 53°F 53°F1012.5 hPa
44043 - Patapsco, MD 42 mi39 min NW 1.9 G 1.9 51°F 1013.5 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 44 mi51 min W 13 G 19 54°F 1013.7 hPa
SLIM2 - 8577330 - Solomons Island, MD 45 mi51 min SW 8.9 G 12 54°F 54°F1012.9 hPa

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
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NW6
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NW16
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA4 mi77 minS 410.00 miOvercast51°F48°F92%1013 hPa
Camp Springs / Andrews Air Force Base, MD9 mi73 minSSW 610.00 miLight Rain51°F49°F92%1013.2 hPa
Fort Belvoir, VA9 mi73 minSE 410.00 miOvercast48°F46°F94%1013.2 hPa
College Park Airport, MD14 mi83 minN 010.00 miOvercast52°F47°F85%1012.5 hPa
Fort Meade / Tipton, MD24 mi84 minN 010.00 miOvercast45°F42°F93%1013.5 hPa

Wind History from DCA (wind in knots)
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Last 24hrS9S5S11
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S10S10S10S7S7SW8SW7S7S7S9S4SW3
1 day agoW8NW8W11W9
G16
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SW11W10W15W16SW8SW8S7S6S9S6SW4SW4SW4SW6S6S7S10S7S8
2 days agoW15
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NW5NW9NW5W9
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G17
NW11NW8

Tide / Current Tables for Alexandria, Virginia
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Alexandria
Click for Map
Wed -- 04:57 AM EST     0.17 feet Low Tide
Wed -- 06:58 AM EST     Sunrise
Wed -- 10:15 AM EST     Moonrise
Wed -- 10:35 AM EST     2.53 feet High Tide
Wed -- 04:36 PM EST     0.18 feet Low Tide
Wed -- 04:49 PM EST     Sunset
Wed -- 08:20 PM EST     Moonset
Wed -- 10:34 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
2.21.610.60.30.20.411.72.22.52.52.21.610.50.20.20.411.82.52.82.8

Tide / Current Tables for Riverview, Potomac River, Maryland
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Riverview
Click for Map
Wed -- 04:38 AM EST     0.12 feet Low Tide
Wed -- 06:58 AM EST     Sunrise
Wed -- 10:15 AM EST     Moonrise
Wed -- 10:17 AM EST     2.34 feet High Tide
Wed -- 04:17 PM EST     0.13 feet Low Tide
Wed -- 04:50 PM EST     Sunset
Wed -- 08:20 PM EST     Moonset
Wed -- 10:16 PM EST     2.62 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.91.30.80.40.20.10.41.11.72.12.32.31.91.30.70.30.10.20.51.11.92.42.62.5

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 (6,6,7,8)
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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.