Saturday, July22, 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 6:00AMSunset 8:29PM Saturday July 22, 2017 10:34 PM EDT (02:34 UTC) Moonrise 4:08AMMoonset 6:51PM Illumination 0% Phase: New Moon; Moon at 29 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- 732 Pm Edt Sat Jul 22 2017
Tonight..SW winds 5 kt. Waves less than 1 ft. Scattered showers and tstms this evening, then widespread showers with a chance of tstms after midnight. Vsby 1 nm or less.
Sun..W winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms.
Sun night..W winds 5 to 10 kt. Waves 1 ft. A chance of showers.
Mon..W winds 5 kt. Waves less than 1 ft.
Mon night..NW winds 5 kt. Waves less than 1 ft.
Tue..N winds 5 kt. Waves less than 1 ft.
Tue night..NE winds 5 kt. Waves less than 1 ft.
Wed..SE winds 5 kt. Waves less than 1 ft.
Thu..SW winds 5 kt. Waves less than 1 ft. A chance of showers and tstms. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 732 Pm Edt Sat Jul 22 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Light winds are expected with high pressure to the south through the weekend. Scattered Thunderstorms are expected each afternoon and evening. A cold front will move through Sunday night.

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 230045
afdlwx
area forecast discussion
national weather service baltimore md washington dc
845 pm edt Sat jul 22 2017

Synopsis
High pressure remains off the southeast coast. Multiple upper
level disturbances will be possible through Sunday. An upper
level trough of low pressure will move over the northeastern us
early in the week.

Near term until 6 am Sunday morning
What the first round didnt stabilize this afternoon, the second
round did. A cluster of thunderstorms currently moving southeast
of point lookout at this time. There is a gap from there back to
round 3, which is entering the potomac highlands. However, a few
cells have been popping up in the void between convective
clusters.

Mesoscale analysis suggests that a few hundred joules of mlcape
present across much of the area. On the other hand, around or in
excess of 1000 j kg present across the highlands southeast
towards charlottesville... Which has not been worked over yet.

Effective shear around 30 kt. So, we're not out of the woods
with respect to vigorous convection yet, but with the loss of
daytime heating, its becoming less about winds and more about
repeated rainfall.

A composite of guidance sources suggest that the third round
should be in the metros (i-95, baltimore-washington corridor)
around 10 pm to midnight. This rapid propagation will be key, as
precipitable water still in excess of 2 inches. If there has
been one adjustment to make wrt timing, precip has been arriving
quicker than progged. Due to that, accumulated rainfall thus
far, and current radar presentation... Have no plans for a flood
watch at this time.

Will be adjusting temperatures, too. Ultimately, the low temp
will be whatever we have after round 3.

Conditions should be quieter overnight. But in this air mass,
cannot rule out a pop-up shower of thunderstorm at any time.

Short term 6 am Sunday morning through Monday
Warm and humid weather Sunday as we continue to reside in the
warm sector and high temperatures remain in the 90s with
dewpoints in the 70s. Heat dome recedes just a bit to the SE as
heights fall... Which will keep the hottest temperatures across
central va... Where a heat advisory appears more likely.

Along east of i-95... Temperatures may be a degree or two cooler
than today... Though, prolonged nature of event, coupled with
heat indices near 100 to perhaps 105f, suggest that a heat
advisory may again be needed... Especially considering the
accumulated effect of the heat and humidity.

Convective evolution tomorrow rather muddled and will likely
depend on the spatiotemporal evolution of convection later
tonight (which will allow finer scale details to become more
clear). While CAPE shear parameters may become more favorable
than they are today (which would enhance storm organization), timing
and evolution will likely determine degree of coverage of the
strongest storm. Gusty winds and a few instances of large hail
are the primary hazards.

A cold front will approach the region Monday before pushing across
the region Monday night. Showers and thunderstorms will develop
along and ahead of this front... Some of which could be strong.

Highs will reach the 90s again.

Long term Monday night through Saturday
A cold front should stall across the virginia and north carolina
border Tuesday, allowing for a few showers to linger across our
southern areas.

High pressure will build in from the west and northwest Tuesday
night and Wednesday. Temperatures will be nearly 10 degrees cooler
than previous days with a comfortable relative humidity.

The next cold front will arrive and push across the region Thursday
into Friday. Another active pattern of showers and thunderstorms
during the period and could linger into the weekend if the front
stalls across portions of the region.

A second area of high pressure will build in for the weekend,
bringing drier and cooler conditions.

Aviation 01z Sunday through Thursday
Thoughts have not changed from this afternoon.VFR conditions
will prevail through Monday... Outside of thunderstorm activity.

Multiple rounds of thunderstorms are possible during this time
(with the best chance during the afternoons and evenings) with
gusty winds and reduced visibility in the strongest storms. A
third round of thunderstorms approaching this evening, and
should be affecting the terminals for 2-3 hrs between 9pm and
1am. More storms likely tomorrow.

Vfr conditions expected Tuesday through Wednesday night. Winds north
10 knots Tuesday, becoming northeast 5 to 10 knots Tuesday night.

Winds light and variable Wednesday and Wednesday night.

Marine
No changes to thoughts from this afternoon. Winds will remain
below SCA values through Monday. However, strong thunderstorms
capable of producing gusty winds above special marine warning
criteria are possible tonight and again Sunday Monday.

No marine hazards expected Tuesday through Wednesday night.

Winds becoming northwest 10 knots Tuesday, then northeast 5 to 10
knots Tuesday night. Winds light and variable Wednesday and
Wednesday night.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... None.

Synopsis... Mse
near term... Hts
short term... Mse
long term... Klw
aviation... Mse hts klw
marine... Mse hts klw


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 5 mi53 min W 8.9 G 9.9 76°F 87°F1009.1 hPa
BSLM2 - Chesapeake Bay, MD 17 mi125 min S 4.1 69°F 1009 hPa69°F
APAM2 - 8575512 - Annapolis, MD 32 mi53 min 76°F 1008.1 hPa
TPLM2 - Thomas Point, MD 32 mi35 min WSW 1.9 G 2.9 76°F 84°F
NCDV2 33 mi53 min S 5.1 G 6 77°F 87°F1007.7 hPa
44063 - Annapolis 33 mi45 min W 3.9 G 5.8 76°F 1009.5 hPa
44062 - Gooses Reef, MD 37 mi45 min S 9.7 G 14 79°F 1009.5 hPa
CPVM2 37 mi53 min 78°F 74°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 39 mi53 min WNW 8.9 G 11 75°F 1008.7 hPa
BLTM2 - 8574680 - Baltimore, MD 40 mi53 min NW 4.1 G 6 76°F 87°F1008.7 hPa
44043 - Patapsco, MD 42 mi45 min WNW 14 G 18 78°F 1009.1 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 44 mi53 min S 14 G 16 78°F 1009.6 hPa
SLIM2 - 8577330 - Solomons Island, MD 45 mi53 min SSE 13 G 17 77°F 84°F

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA4 mi43 minSW 14 G 224.00 miThunderstorm Heavy Rain Fog/Mist76°F73°F94%1010 hPa
Camp Springs / Andrews Air Force Base, MD9 mi3.6 hrsS 510.00 miLight Drizzle73°F70°F91%1009.6 hPa
Fort Belvoir, VA9 mi3.6 hrsSE 510.00 miLight Rain73°F70°F92%1009.4 hPa
College Park Airport, MD14 mi47 minN 07.00 miMostly Cloudy73°F71°F94%1009.5 hPa
Fort Meade / Tipton, MD24 mi47 minN 07.00 miPartly Cloudy72°F69°F94%1010.2 hPa

Wind History from DCA (wind in knots)
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Last 24hrSW4NW8NW8N9N9N8NW6N8N10N9N5W3SE4NE4CalmW11NW21
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1 day agoS6S5CalmNW7NW6NW5CalmSW3N5N7N10NW8N3E4SE5S8CalmNW7SW65S4S6S5S7
2 days agoS6S6S7S5S4S4SW5SW4CalmCalmN6N6NW756SW76W9W9SW8SW9S7S7S8

Tide / Current Tables for Alexandria, Virginia
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Alexandria
Click for Map
Sat -- 01:46 AM EDT     0.13 feet Low Tide
Sat -- 05:08 AM EDT     Moonrise
Sat -- 06:01 AM EDT     Sunrise
Sat -- 07:36 AM EDT     3.62 feet High Tide
Sat -- 02:43 PM EDT     -0.05 feet Low Tide
Sat -- 07:50 PM EDT     Moonset
Sat -- 08:14 PM EDT     3.14 feet High Tide
Sat -- 08:27 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.60.20.10.51.32.33.13.53.63.22.51.81.10.60.1-00.41.32.22.83.132.41.7

Tide / Current Tables for Riverview, Potomac River, Maryland
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Riverview
Click for Map
Sat -- 01:29 AM EDT     0.11 feet Low Tide
Sat -- 05:08 AM EDT     Moonrise
Sat -- 06:01 AM EDT     Sunrise
Sat -- 07:18 AM EDT     3.33 feet High Tide
Sat -- 02:27 PM EDT     -0.03 feet Low Tide
Sat -- 07:50 PM EDT     Moonset
Sat -- 07:57 PM EDT     2.86 feet High Tide
Sat -- 08:27 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.40.20.20.61.52.433.33.22.72.11.40.90.4000.61.42.22.72.92.621.4

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 (22,6,7,8)
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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.