Monday, May29, 2017 L-36.com


Marine Weather and Tides
George Mason, VA

Version 3.4
What's New / NOTES
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 5:45AMSunset 8:28PM Monday May 29, 2017 1:10 PM EDT (17:10 UTC) Moonrise 8:52AMMoonset 11:18PM Illumination 18% 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- 1032 Am Edt Mon May 29 2017
Rest of today..W winds 5 kt. Waves less than 1 ft. Areas of fog late this morning. Isolated showers and tstms this afternoon. Vsby 1 to 3 nm late this morning.
Tonight..E winds 5 kt. Waves less than 1 ft. Patchy fog. Vsby 1 to 3 nm.
Tue..SE winds 5 kt. Waves less than 1 ft. A chance of showers and tstms. Patchy fog. Vsby 1 to 3 nm.
Tue night..SW winds 5 kt. Waves less than 1 ft. A chance of showers and tstms.
Wed..W winds 5 to 10 kt. Waves 1 ft.
Wed night..W winds 5 kt. Waves less than 1 ft.
Thu..S winds around 5 kt. Waves 1 ft or less.
Fri..SW winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 1032 Am Edt Mon May 29 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front will move toward the waters this afternoon...but stall and weaken by tonight. Another weak front will approach late Tuesday...also stalling and weakening. A third cold front will finally push through Wednesday night, with high pressure following on Thursday. A warm front will lift northward on Friday.

7 Day Forecast for Marine Location Near George Mason, VA
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location: 38.84, -77.3     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 291404
afdlwx
area forecast discussion
national weather service baltimore md washington dc
1004 am edt Mon may 29 2017

Synopsis
Upper level low pressure will drift east across the north side
of the great lakes this week. In the meantime, weak high
pressure will prevail over the mid atlantic outside of weak
cold frontal passages Tuesday night and Wednesday night. Low
pressure approaches from the west this weekend.

Near term through tonight
Latest observations and satellite pictures indicate the edge of
low clouds on the doorstep of fdk-iad-ezf, with a pretty sharp
improvement west of there. Therefore, am hopeful that we'll be
able to see a period of Sun today, before any diurnal cu
develop.

It remain possible that the frontal convergence zone crossing
the forecast area may spark a few showers and perhaps a
thunderstorm across the eastern quarter of the area. Have
preserved a period of isolated- scattered showers thunderstorms
along and east of i-95. Atmosphere remains stable due to the
morning wedge, and doubt we'll be able to recover from that.

The front trough axis becomes more nebulous tonight, as it will
stall near the bay. Onshore flow will be re-introduced, bring a
return of lower clouds, especially the northeastern quadrant of
the area. Fog and reduced visibility will be possible, whether
due to low clouds (east) or radiational cooling of the moist
airmass (west). Low pressure will develop along the frontal zone
to our south, which could bring a shower threat to the far
southeast, but otherwise dry. Lows will be in the upper 50s to
mid 60s.

Short term Tuesday through Wednesday night
Upper level low pressure will continue to spin over ontario
Tuesday and Wednesday with the jet stream located just to our
northwest. Surface features will continue to be less defined
though, as weak fronts (more pressure troughs than huge airmass
differences) waver across the region.

The first will push southeast on Tuesday afternoon. With low
stratus to start the day, it is uncertain how quickly and how
far east it will erode. West of the marine air, modest
instability will develop. Deep layer shear increases in
magnitude with northward extent. Thus there is some risk of
strong gusty thunderstorms developing ahead of the front. Spc
has placed northern parts of the area in a marginal risk.

This front will lose its definition as it slips southward
Tuesday night, ending the chance for showers. A final and
slightly more well- defined front will push south Wednesday
afternoon and evening. While low level convergence isn't great,
some scattered showers and storms will still develop along the
front. The front will align better with diurnal heating to our
west, so expect a decreasing trend for any storms that enter the
area. Once again though, deep layer shear will be strong, so
any organized storms could have a gusty wind threat. A marginal
risk is in place for the northwestern half of the area.

Highs both days will be in the 70s and 80s with lows in the 50s
and 60s.

Long term Thursday through Sunday
Canadian high pressure will dominate Thursday as a trough
passes aloft. Warm air will begin returning northward on Friday,
but by Saturday the next cold front is already dropping back
south across the region as another trough rotates around the
stalled upper low over southern canada. That front looks to
stall south of the region by Sunday as the upper low starts
moving further east, with the front perhaps lifting back north
as a warm front early next week. We will have a chance of
showers and thunderstorms with the front dropping south across
the area late Friday into Saturday. By Sunday, with the
potential for the front to stall south of us, the weather is
uncertain, but if high pressure builds in strongly enough from
the north, it could be dry. Temperatures will mostly be cooler
than normal, with the warmest day likely Friday.

Aviation 14z Monday through Friday
Low clouds have moved east of mrb cho already, and based on
current progress should see return ofVFR to iad dca shortly.

It'll be a little bit longer for bwi mtn as they're more
entrenched in the wedged marine air, but current trends suggest
thatVFR should return before noon.

A few showers may redevelop around baltimore this afternoon,
but not enough coverage to put in the taf.

Onshore flow will redevelop tonight. Low MVFR or ifr likely in
baltimore area, and possible at the rest of the terminals except
cho. It's uncertain how quickly these clouds will erode on
Tuesday as well. Where they do, thunderstorms will be possible
during the afternoon and evening as the next boundary drops
southeast.

It's possible the low cloud pattern repeats Tuesday night as
the front washes out. A more well-defined cold front will push
through late Wednesday with scattered showers and thunderstorms
possible.

MainlyVFR later this week with high pressure returning.

Thunderstorm chances are maximized late Friday into Saturday
with a passing front.

Marine
Overall light flow is expected on the waters through Wednesday.

Expect variable wind directions as weak boundaries waffle
across the area, though onshore flow may persist more often than
not until a more defined cold front passes through Wednesday
night. With the frontal passage after sunset, am not thinking
strong winds will be found in its wake. Also can't completely
rule out a few thunderstorms each day, mainly focused in the
afternoon and evening, although it's uncertain how many reach
the waters at this time.

Sub-sca winds expected later this week. Thunderstorm chances
increase late Friday with an approaching front.

Tides coastal flooding
Water levels remain high and should continue above normal for
the next few cycles due to the persistent onshore flow.

Advisories remain for anne arundel and alexandria dc for this
morning's high tide cycle, and for st. Marys for this
afternoon evening's high tide cycle. It is also probable that
additional advisories will be needed for high tide cycles
through Tuesday for the sensitive locations, and possibly
elsewhere. After Tuesday, northerly flow may finally allow
anomalies to start falling.

Lwx watches warnings advisories
Dc... Coastal flood advisory until 2 pm edt this afternoon for
dcz001.

Md... Coastal flood advisory until 1 pm edt this afternoon for
mdz014.

Coastal flood advisory until 10 pm edt this evening for mdz017.

Va... Coastal flood advisory until 2 pm edt this afternoon for
vaz054.

Wv... None.

Marine... None.

Synopsis... Rcm
near term... Hts ads
short term... Ads
long term... Rcm
aviation... Hts ads rcm
marine... Ads rcm
tides coastal flooding... Rcm mm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 15 mi41 min SSW 2.9 G 6 74°F 67°F1012.3 hPa
BSLM2 - Chesapeake Bay, MD 32 mi101 min E 1 73°F 1012 hPa63°F
NCDV2 39 mi41 min SE 6 G 7 72°F 72°F1012.5 hPa
APAM2 - 8575512 - Annapolis, MD 45 mi41 min 69°F 1012.9 hPa
44063 - Annapolis 46 mi31 min ESE 3.9 G 3.9 64°F 1013.5 hPa
TPLM2 - Thomas Point, MD 46 mi71 min E 1.9 G 2.9 64°F 65°F
BLTM2 - 8574680 - Baltimore, MD 48 mi41 min E 1.9 G 4.1 66°F 68°F1013 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 49 mi41 min ESE 2.9 G 4.1 65°F 1013.6 hPa
FSNM2 49 mi41 min E 1.9 G 4.1 65°F 1013.3 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA10 mi73 minSSE 310.00 miA Few Clouds74°F66°F75%1012.8 hPa
Washington/Dulles International Airport, DC, VA11 mi79 minNW 610.00 miMostly Cloudy77°F63°F62%1012.3 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA14 mi75 minVar 510.00 miMostly Cloudy76°F66°F72%1013.5 hPa
Washington/Reagan National Airport, DC, VA14 mi79 minSE 410.00 miMostly Cloudy74°F66°F79%1012.6 hPa
College Park Airport, MD22 mi78 minN 010.00 miPartly Cloudy71°F64°F80%1012.5 hPa
Leesburg / Godfrey, VA22 mi76 minNW 5 G 910.00 miPartly Cloudy79°F66°F65%1012.9 hPa
Camp Springs / Andrews Air Force Base, MD23 mi73 minNNW 610.00 miA Few Clouds74°F64°F71%1013 hPa
Quantico Marine Corps Airfield - Turner Field, VA23 mi75 minSSW 610.00 miPartly Cloudy74°F69°F85%1013.1 hPa
Gaithersburg - Montgomery County Airport, MD24 mi75 minWNW 810.00 miOvercast74°F64°F71%1015.5 hPa

Wind History from DAA (wind in knots)
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Last 24hrCalmCalmCalmNE3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS5SE3SE6
1 day agoCalmCalmCalmNE3NE3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmSE5NE3CalmSE4E4
2 days agoNW15
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NW13NW16
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NW5CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS3S5S3SE5E3

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Mon -- 05:46 AM EDT     Sunrise
Mon -- 06:31 AM EDT     0.16 feet Low Tide
Mon -- 09:51 AM EDT     Moonrise
Mon -- 12:05 PM EDT     3.70 feet High Tide
Mon -- 07:20 PM EDT     -0.04 feet Low Tide
Mon -- 08:26 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.332.41.71.10.60.20.20.71.72.83.53.73.52.92.21.50.90.4-00.10.81.82.6

Tide / Current Tables for Chain Bridge, Washington, D.C.
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Chain Bridge
Click for Map
Mon -- 05:46 AM EDT     Sunrise
Mon -- 06:33 AM EDT     0.18 feet Low Tide
Mon -- 09:51 AM EDT     Moonrise
Mon -- 12:06 PM EDT     3.65 feet High Tide
Mon -- 07:22 PM EDT     -0.02 feet Low Tide
Mon -- 08:26 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.332.41.71.10.60.30.20.71.72.73.43.63.52.92.21.60.90.400.10.81.72.6

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 (13,3,4,5)
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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.