Saturday, September23, 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 6:56AMSunset 7:03PM Saturday September 23, 2017 8:41 AM EDT (12:41 UTC) Moonrise 9:11AMMoonset 8:18PM Illumination 8% Phase: Waxing Crescent; Moon at 3 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
    EDIT      (on/off)   Help
ANZ535 Tidal Potomac From Key Bridge To Indian Head- 732 Am Edt Sat Sep 23 2017
Today..N winds 5 kt. Waves less than 1 ft.
Tonight..NW winds around 5 kt. Waves 1 ft.
Sun..N winds 5 kt. Waves less than 1 ft.
Sun night..N winds around 5 kt. Waves 1 ft.
Mon..NE winds around 5 kt. Waves 1 ft.
Mon night..NE winds around 5 kt. Waves 1 ft.
Tue..NE winds around 5 kt. Waves 1 ft.
Wed..N winds 5 kt. Waves less than 1 ft.
ANZ500 732 Am Edt Sat Sep 23 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A ridge of high pressure will remain over the eastern united states through early next week. Small craft advisories may be needed Tuesday and Wednesday as hurricane maria approaches north carolina. Refer to the latest statements from the national hurricane center for up-to-date information on hurricane maria.

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


Area Discussion for - Baltimore, MD/Washington
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus61 klwx 230802
afdlwx
area forecast discussion
national weather service baltimore md washington dc
402 am edt Sat sep 23 2017

Synopsis
Surface and upper level high pressure will remain in place through
the weekend and into early next week. The high will slowly
weaken its grip over the area by the middle of the week as
hurricane maria moves northward through the western atlantic.

Near term through tonight
Have seen some patchy, locally dense fog early this morning,
especially in the frederick, maryland area, and in the
manassas-warrenton corridor of northern virginia. It would
probably be more widespread, but some high clouds remain over
the shenandoah valley and potomac highlands.

Once the fog burns off this morning, it will be another largely
sunny and unseasonably warm day. Highs should be at least a
couple degrees warmer than yesterday... Mostly in the mid 80s.

Overnight, another possibility for patchy fog to develop with
lows mainly in the 60s, except in the urban centers, where
temperatures may stay around 70.

Short term Sunday through Monday night
On Sunday and Monday, the upper ridge is at its strongest over
our area, which should also yield the warmest (dare I say
hottest?) temperatures of this stretch. Can't rule out that we
hit 90 in some spots. Even 89 degrees would be the warmest we
have seen in over a month. Dewpoints will start creeping upward
too, and that means uncomfortable humidity levels for late
september, but nothing to spark any precipitation through Monday
night.

Long term Tuesday through Friday
The long term period will be dominated by attention to hurricane
maria. On Tuesday, ridge axis will be to our north, with maria
pushing northwest from the south. Latest guidance has shifted a bit
west somewhat, bringing the storm closer to the north carolina outer
banks than previous runs. Guidance now stalls the storm just
southeast of the outer banks Wednesday before the next strong upper
trough and cold front moving in from the northwest finally starts
kicking it out to sea on Thursday. While most guidance still does
not show a significant impact in our region, attention should
continue to be paid to this storm until it moves safely out to sea.

Please refer to the latest products from the national hurricane
center for the most up-to-date information on hurricane maria.

Behind the cold front (which could bring a few showers regardless of
what maria does), temperatures will drop significantly Friday into
Saturday. The long september warm spell looks likely to end.

Aviation 06z Saturday through Wednesday
MVFR visibility possible at cho mrb iad this morning and again
tonight. Otherwise,VFR with light winds and just a few clouds
through the valid TAF period, and continuing through Monday.

Attention will be on hurricane maria during Tuesday and Wednesday.

While subVFR conditions are not likely, a gusty northwest breeze of
15-20 knots is possible, as are a few showers. A further deviation
northwest in the track of maria could bring worse conditions. Refer
to latest NHC statements for up-to-date information on maria.

Marine
High pressure will allow for light winds around 10 knots or less
through the weekend. Perhaps some patchy fog on the waters
overnight.

Sca winds looking likely across the waters on Tuesday and Wednesday
as hurricane maria approaches and we get enveloped by its expanding
wind field. A few showers will also be possible. If the storm's
track deviates further northwest, more significant impacts are
possible (though not likely). Refer to latest NHC statements for up-
to-date information on maria.

Tides coastal flooding
September is always a prime month for tidal flooding and this
is proving to be no exception. Minor coastal flooding is
forecast to persist through this morning's tide cycle and likely
this afternoon's tide cycle from annapolis southward on the
western shore of the bay and on the lower tidal potomac.

Outlook... Dc will be close to minor threshold with tonight's
tide cycle if current tidal departures rise at all. Straits
point (st. Mary's potomac side) will likely continue to see
tidal flooding around high tide through at least the Sunday
afternoon tide cycle. Elsewhere, things are more in question due
to the light winds. Local research has shown that in light wind
regimes, the tidal anomaly locally is more controlled by what's
coming in to the lower bay. Those anomalies are currently higher
than what we have locally, and seem unlikely to drop much, so
our forecast might prove to be optimistically low on Sunday Monday.

Lwx watches warnings advisories
Dc... None.

Md... Coastal flood advisory until 10 pm edt this evening for mdz018.

Coastal flood advisory until 1 am edt Sunday for mdz014.

Coastal flood advisory until 9 pm edt this evening for mdz017.

Va... None.

Wv... None.

Marine... None.

Synopsis... Je
near term... Je
short term... Je
long term... Rcm
aviation... Je rcm
marine... Je rcm
tides coastal flooding... Je


Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map
Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 5 mi41 min W 1.9 G 1.9 68°F 76°F1018.5 hPa (+1.4)
BSLM2 - Chesapeake Bay, MD 17 mi131 min NW 1 53°F 1018 hPa53°F
APAM2 - 8575512 - Annapolis, MD 32 mi41 min 72°F 1017.5 hPa (+1.4)
TPLM2 - Thomas Point, MD 32 mi41 min NW 6 G 6 68°F 75°F
NCDV2 33 mi41 min NNW 2.9 G 5.1 67°F 76°F1017.2 hPa (+1.3)
44063 - Annapolis 33 mi31 min N 7.8 G 9.7 70°F 1017.8 hPa
44062 - Gooses Reef, MD 37 mi31 min N 7.8 G 9.7 73°F 10 ft1018.2 hPa
CPVM2 37 mi41 min 71°F 61°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 39 mi41 min WNW 6 G 7 69°F 1018.1 hPa (+1.4)
BLTM2 - 8574680 - Baltimore, MD 40 mi41 min N 2.9 G 5.1 70°F 78°F1017.8 hPa (+1.3)
44043 - Patapsco, MD 42 mi31 min NNW 7.8 G 7.8 72°F 1 ft1018.7 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 44 mi41 min NNE 12 G 14 74°F 1018.1 hPa (+1.0)
SLIM2 - 8577330 - Solomons Island, MD 45 mi41 min NNW 6 G 8 70°F 76°F1017.1 hPa (+1.0)

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
Last
24hr
W1
NW4
NW4
NW2
W5
NW6
G9
N7
G10
N8
NW7
G10
NW6
G9
NW1
S1
--
NW2
W1
NW2
NW2
NW2
--
--
--
N1
W1
W2
1 day
ago
W2
W3
SW4
SW2
NW9
N3
G8
N3
G6
NE2
G6
NW5
G8
NW4
N6
G9
N3
NW2
--
NW1
NW1
NW3
NW3
NW3
NW2
NW3
W1
NW2
NW3
2 days
ago
NW5
NW7
NW3
G9
NW6
W8
NW5
G9
NW5
NW8
G11
NW5
G10
NW6
NW5
N1
--
--
SW1
NW3
NW2
NW1
NW3
NW2
W2
NW3
NW1
NW1

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA4 mi49 minN 610.00 miPartly Cloudy68°F59°F73%1018.6 hPa
Camp Springs / Andrews Air Force Base, MD9 mi1.7 hrsNNW 310.00 miFair62°F52°F73%1018.4 hPa
Fort Belvoir, VA9 mi1.8 hrsN 010.00 miFair60°F58°F96%1018.6 hPa
College Park Airport, MD14 mi56 minN 010.00 miFair59°F57°F94%1018.3 hPa
Fort Meade / Tipton, MD24 mi56 minN 010.00 miFair55°F55°F100%1019 hPa

Wind History from DCA (wind in knots)
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
Last 24hrN5N43E4CalmNW9NW9N9W9NW9N5N3CalmCalmCalmCalmN6N6N6N6N6N6N4N6
1 day agoN6N4N4CalmN7N9N6NW7N4NW7N6N7N6N5CalmCalmCalmCalmN6N7NW6N6N6N6
2 days agoNW7NW8NW10NW10NW9NW6NW3NW11NW6NW8NW8NW6N6CalmS3E3CalmN4CalmNW6N7N5N6N5

Tide / Current Tables for Alexandria, Virginia
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Alexandria
Click for Map
Sat -- 05:29 AM EDT     0.22 feet Low Tide
Sat -- 06:56 AM EDT     Sunrise
Sat -- 10:11 AM EDT     Moonrise
Sat -- 11:07 AM EDT     3.18 feet High Tide
Sat -- 05:32 PM EDT     0.23 feet Low Tide
Sat -- 07:03 PM EDT     Sunset
Sat -- 09:18 PM EDT     Moonset
Sat -- 11:24 PM EDT     3.36 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
32.41.71.10.60.30.30.81.62.42.93.232.41.71.10.60.30.30.71.52.433.3

Tide / Current Tables for Riverview, Potomac River, Maryland
   EDIT      (on/off)   Help   One Week of Data
Riverview
Click for Map
Sat -- 05:12 AM EDT     0.19 feet Low Tide
Sat -- 06:56 AM EDT     Sunrise
Sat -- 10:11 AM EDT     Moonrise
Sat -- 10:50 AM EDT     2.91 feet High Tide
Sat -- 05:15 PM EDT     0.21 feet Low Tide
Sat -- 07:03 PM EDT     Sunset
Sat -- 09:18 PM EDT     Moonset
Sat -- 11:06 PM EDT     3.08 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.621.40.90.50.20.30.91.72.42.82.92.621.40.80.40.20.30.81.62.42.93.1

Weather Map and Satellite Images
       (on/off)   Help
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 (8,2,3,4)
      (on/off)   Help

Ground Weather Radar Station Sterling, VA
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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.