Tuesday, August22, 2017 L-36.com


Marine Weather and Tides
Annandale, 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 6:28AMSunset 7:54PM Tuesday August 22, 2017 8:48 PM EDT (00:48 UTC) Moonrise 6:17AMMoonset 7:39PM Illumination 1% Phase: New Moon; Moon at 1 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 Tue Aug 22 2017
.small craft advisory in effect until 2 am edt Wednesday...
Tonight..W winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft. A chance of showers with a slight chance of tstms.
Wed..NW winds 5 kt. Waves less than 1 ft. A chance of showers and tstms.
Wed night..N winds 5 kt. Waves less than 1 ft. A chance of showers.
Thu..N winds 5 kt. Waves less than 1 ft.
Thu night..N winds 5 kt. Waves less than 1 ft.
Fri..N winds 5 kt. Waves less than 1 ft.
Fri night..N winds around 5 kt. Waves 1 ft.
Sat..NE winds around 5 kt. Waves 1 ft.
Sun..NE winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 732 Pm Edt Tue Aug 22 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front will cross the waters late tonight into early Wednesday. High pressure will return for the second half of the week.

7 Day Forecast for Marine Location Near Annandale, VA
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location: 38.83, -77.22     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 221852 cca
afdlwx
area forecast discussion... Corrected
national weather service baltimore md washington dc
252 pm edt Tue aug 22 2017

Synopsis
High pressure is centered well off the north carolina coast. A
cold front over western ohio will track across the mid-
atlantic tonight into Wednesday morning. Reinforcing upper level
energy will help to push the front offshore and allow for high
pressure to build in from the northwest Thursday into Friday.

Near term tonight
Temperatures in the lower 90s and dewpoints in the low 70s have
led to another day with capes of 1000-2000. It is a different
synoptic situation from yesterday as we have our eyes on a
front line of storms stretching from ontario to southern il.

Watches are in effect to our west and north. Aside from any
isolated cells that fire ahead of the line the main possibility
of convection looks to be from around 9 pm over the mountains to
after midnight by the bay. Models have consistent in weakening
the cells once these move east of the blue ridge. Yes heating
will be over CAPE will be diminishing but think given the
amount of energy in the atmosphere still believe severe storms
could be possible through midnight.

Storms should weaken after midnight with pops decreasing from nw
to se.

Lows in the mid to upper 60s west of the mountains... Low to mid
70s east.

Short term Wednesday through Thursday night
Showers isolated thunderstorms will be possible across the
southern 2 3 of the forecast area Wednesday. By Wednesday
precipitation should be well offshore. Tonight's FROPA will
bring an end to this recent heat wave. Highs Wednesday back
into the mid 80s dewpoints beack into 60s. Conditions will
continue to become more comfortable Wednesday night and
Thursday.

Long term Friday through Monday
The long term period looks fairly dry with surface high
pressure dominating the weather conditions over our area. Some
diurnally or terrain driven showers and thunderstorms could
develop at times with shortwaves moving through, but at this
moment looking at mostly dry weather conditions. Temperatures
will be slightly below normal, with highs around 80 degrees,
near 70 at higher elevations.

Aviation 18z Tuesday through Sunday
The concern is the cold front across the ohio valley. While the
strongest activity is expected to be to our north showers and
thunderstorms could reduce visibilities to ifr in heavy rainfall
this evening.

Vfr conditions expected at all terminals after midnight through
Thursday night.

MainlyVFR conditions expected Friday into Sunday with high
pressure building over our area.

Marine
Small craft advisories in effect through 11 pm tonight.

Thunderstorms are expected to be weakening tonight by the time
these reach the waters but smw wind gusts may still be possible.

No marine hazards expected Wednesday through Thursday night.

Wind gusts are expected to stay below the small craft advisory
threshold.

Tides
Anomalies are around 0.5 to 0.6 ft this afternoon. The coming high
tide is lower astronomically and no flooding is expected. Then
northwest winds will arrive Wednesday morning. We will have to see
if that will be soon enough to preclude another borderline situation
at annapolis, straits point, and dc early Wednesday.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory until 11 pm edt this evening for
anz530>543.

Products... Woody! Imr ads


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 11 mi48 min S 9.9 G 14 87°F 84°F1009.4 hPa (-0.8)
BSLM2 - Chesapeake Bay, MD 27 mi138 min S 7 87°F 1010 hPa73°F
NCDV2 37 mi48 min SSW 8.9 G 13 86°F 84°F1010 hPa (-0.6)
APAM2 - 8575512 - Annapolis, MD 41 mi48 min 86°F 1009.6 hPa (-0.8)
TPLM2 - Thomas Point, MD 42 mi48 min S 18 G 20 85°F 81°F
44063 - Annapolis 42 mi38 min W 16 G 19 1 ft
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 45 mi48 min S 12 G 15 86°F 1009.5 hPa (-0.8)
BLTM2 - 8574680 - Baltimore, MD 45 mi48 min SW 6 G 14 87°F 84°F1009.2 hPa (-0.7)
CPVM2 46 mi48 min 84°F 80°F
44062 - Gooses Reef, MD 47 mi38 min S 12 G 14 85°F 1 ft1011.5 hPa
44043 - Patapsco, MD 49 mi38 min SSW 14 G 16 84°F 1 ft1010.6 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA7 mi1.8 hrsSSE 610.00 miFair88°F72°F60%1010.7 hPa
Washington/Reagan National Airport, DC, VA10 mi56 minS 1210.00 miPartly Cloudy87°F75°F70%1010.1 hPa
Washington/Dulles International Airport, DC, VA15 mi56 minS 810.00 miPartly Cloudy85°F72°F65%1009.7 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA18 mi52 minS 710.00 miFair85°F73°F68%1011 hPa
College Park Airport, MD19 mi60 minS 510.00 miFair87°F71°F59%1010.2 hPa
Camp Springs / Andrews Air Force Base, MD19 mi50 minS 1210.00 miFair85°F70°F62%1010.9 hPa
Quantico Marine Corps Airfield - Turner Field, VA23 mi52 minSSW 1110.00 miFair87°F75°F70%1010.6 hPa
Gaithersburg - Montgomery County Airport, MD24 mi52 minS 710.00 miFair86°F70°F59%1012.5 hPa

Wind History from DAA (wind in knots)
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Last 24hrCalmCalmSE3SE3CalmCalmCalmCalmCalmCalmCalmS3S5S6S4S6S8S10S10S8
G16
S8S7S6SE5
1 day agoCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS4S6S3SE7S7S6CalmSW5S5S3S6Calm
2 days agoCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmNW4NW3NW3N3NW8NW6CalmCalmNW3NW5CalmS4Calm

Tide / Current Tables for Key Bridge, Washington, D.C.
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Key Bridge
Click for Map
Tue -- 03:46 AM EDT     0.02 feet Low Tide
Tue -- 06:28 AM EDT     Sunrise
Tue -- 07:16 AM EDT     Moonrise
Tue -- 09:24 AM EDT     3.66 feet High Tide
Tue -- 04:21 PM EDT     -0.07 feet Low Tide
Tue -- 07:53 PM EDT     Sunset
Tue -- 08:37 PM EDT     Moonset
Tue -- 09:53 PM EDT     3.46 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.91.20.60.200.51.42.43.23.63.632.31.610.4-00.10.81.82.73.33.53.1

Tide / Current Tables for Chain Bridge, one mile below, Washington, D.C.
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Chain Bridge
Click for Map
Tue -- 03:51 AM EDT     0.02 feet Low Tide
Tue -- 06:28 AM EDT     Sunrise
Tue -- 07:16 AM EDT     Moonrise
Tue -- 09:29 AM EDT     3.66 feet High Tide
Tue -- 04:26 PM EDT     -0.07 feet Low Tide
Tue -- 07:53 PM EDT     Sunset
Tue -- 08:37 PM EDT     Moonset
Tue -- 09:58 PM EDT     3.46 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.91.20.70.200.41.32.43.23.63.63.12.41.710.4-000.71.72.63.23.53.2

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 (20,4,5,8)
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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.