Monday, May29, 2017 L-36.com


Marine Weather and Tides
Arlington, 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 5:43AMSunset 8:27PM Monday May 29, 2017 3:00 PM EDT (19:00 UTC) Moonrise 8:50AMMoonset 11:17PM 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
    EDIT      (on/off)   Help
ANZ535 Tidal Potomac From Key Bridge To Indian Head- 212 Pm Edt Mon May 29 2017
This afternoon..W winds 5 kt. Waves less than 1 ft. A chance of showers with a slight chance of tstms.
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. 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 212 Pm Edt Mon May 29 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A surface boundary will stall across the waters this afternoon... 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 Arlington, VA
   Hourly   EDIT   Help
location: 38.87, -77.06     debug


Area Discussion for - Baltimore, MD/Washington
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus61 klwx 291841
afdlwx
area forecast discussion
national weather service baltimore md washington dc
241 pm 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 Tuesday
The marine wedge has eroded across the forecast area, and
resides just across the eastern shore at this time. The surface
boundary extends down i-95. There is not much thermal contrast
anymore, but there is still weak surface convergence. That,
combined with modest instability (mlcape around 500 j kg) and
good shear (40-50 kt effective bulk) has resulted in widely
scattered showers across southern maryland and the
fredericksburg area of virginia. Would not rule out a
thunderstorm or two, but conditions do not appear favorable for
anything strong. These should dissipate by sunset.

With ample low level moisture (dewpoints in the 60s) along the
metro corridor and without anything impeding it, the marine
wedge should return tonight. The only questions are how soon it
will return and how far west it will make it. Current NAM gfs
plus latest rap hrrr suggest at least to the blue ridge if not
i-81. Am taking an overcast layer to cho-mrb. Believe the pops
in MOS data drizzle. Have not yet added it to weather, but will
advise evening forecaster.

Tuesday morning will be a struggle to erode marine air mass once
again. That will impede afternoon thunderstorm development.

However, the right rear quad of the upper jet, differential
heating, and another surface boundary supported by a 500 mb
shortwave should provide the catalyst for scattered if not
numerous showers. Guidance generating enough CAPE west of the
maritime layer to justify including chance thunder.

Short term Tuesday night through Wednesday night
We will have one more front with shortwave support to contend
with... This time late Wednesday. Have not made many changes to
the database in association with this feature (still chance
pops). In keeping with this pattern, have been reserved in use
of thunder. Clouds should be numerous in advance of the front.

One difference though is that this time it appears as though we
will have a decent push of drier air behind the front, to
support clearing skies Wednesday night.

Decent consistency in guidance temps. Have not strayed far from
an ensemble blend.

Long term Thursday through Monday
Thu is looking like a very pleasant day with canadian high pressure
settling in over the region for the first time in quite awhile.

Plentiful sunshine and highs near or even slightly cooler than
normal for the first day of june. It will be short lived however. By
Saturday morning the next cold front is slowing as it approaches
us from the north early Saturday. It will likely stall over or very
close to us over the weekend, with low pressure riding along west to
east across it and over us Sunday.

Aviation 18z Monday through Saturday
Vfr for now, but AOB ifr (low clouds and vsbys) should return
tonight as marine layer spreads inland again. High confidence in
its occurrence; questions revolve around timing. Current tafs
on the conservative side, taking restrictions just for the
morning push; it could be sooner.

Erosion Tuesday will be a challenge as well. Restrictions will
into mid morning if not later. Then, afternoon showers and
thunderstorms a good possibility. These flight restrictions
should be brief.

Wouldn't rule out more fog-related restrictions early wed
morning, followed by another round of possible thunderstorms wed
afternoon.

Vfr likely for rest of week.

Marine
Flow pattern should be light for most of the week. Bigger
concern would be fog tonight into Tue morning. Lesser chance tue
night into Wed morning. By late Wednesday, a cold front should
dry airmass out.

There could also be a few thunderstorms each afternoon through
Wednesday, although not likely strong.

Tides coastal flooding
Water levels remain high and should continue to be above normal for
the next couple of days due to the persistent onshore flow.

Coastal flood advisories are in place for washington dc and st.

Marys for this evening's high tide cycle, which is the lower of the
next two cycles. The advisory for st. Marys continues through
Tuesday and additional advisories may be necessary at other sites
for Tuesday morning's cycle. It is also likely that additional
advisories will be needed for high tide cycles through Wednesday for
the sensitive locations, and possibly elsewhere. By Thursday,
northwesterly flow as high pressure builds in should finally allow
anomalies to drop.

Lwx watches warnings advisories
Dc... Coastal flood advisory from 11 pm this evening to 2 am edt
Tuesday for dcz001.

Md... Coastal flood advisory until midnight edt Tuesday night for
mdz017.

Va... None.

Wv... None.

Marine... None.

Synopsis... Rcm
near term... Hts
short term... Hts
long term... Cas
aviation... Hts
marine... Hts
tides coastal flooding... Mm


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 2 mi43 min S 4.1 G 6 77°F 67°F1012.6 hPa
BSLM2 - Chesapeake Bay, MD 20 mi151 min N 1.9 72°F 1013 hPa63°F
APAM2 - 8575512 - Annapolis, MD 32 mi43 min 68°F 1013.4 hPa
TPLM2 - Thomas Point, MD 33 mi61 min SE 8 G 9.9 67°F 67°F
44063 - Annapolis 33 mi41 min E 5.8 G 7.8 67°F 1013.8 hPa
FSNM2 37 mi43 min ESE 8.9 G 9.9 67°F 1013.5 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 37 mi43 min ESE 8.9 G 9.9 67°F 1013.5 hPa
CPVM2 37 mi43 min 69°F 65°F
BLTM2 - 8574680 - Baltimore, MD 37 mi43 min S 8.9 G 12 70°F 68°F1012.9 hPa
NCDV2 38 mi43 min ESE 7 G 7 74°F 75°F1012.5 hPa
44062 - Gooses Reef, MD 40 mi41 min ENE 5.8 G 7.8 69°F 1014.7 hPa
44043 - Patapsco, MD 40 mi41 min E 7.8 G 9.7 66°F 1014.6 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 48 mi43 min SSE 8 G 8.9 67°F 1014.6 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 49 mi43 min N 8.9 G 9.9 66°F 66°F1014.2 hPa

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
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
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
Last
24hr
--
E2
G5
--
N2
NE1
SE1
G5
E3
--
N1
E2
SE2
E2
--
--
--
NE3
SE3
--
W1
W1
SE2
S2
S5
S2
1 day
ago
SE2
SE1
G5
NE2
G6
E1
G4
--
S2
N1
--
N2
NE3
E1
--
E1
--
NE2
--
NE3
SE3
SE4
G7
SE7
G10
SE4
G7
SE3
G6
E1
G5
2 days
ago
NW14
G19
NW9
G20
NW10
G15
NW7
G15
NW11
G15
NW4
G9
NW6
G9
NW1
G4
--
--
S1
--
--
--
--
--
--
--
--
--
--
--
NE2
NE2

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA2 mi69 minSE 510.00 miMostly Cloudy79°F66°F67%1013.1 hPa
Camp Springs / Andrews Air Force Base, MD10 mi63 minW 610.00 miPartly Cloudy79°F63°F58%1013.7 hPa
College Park Airport, MD11 mi68 minNNW 610.00 miPartly Cloudy79°F63°F58%1012.9 hPa
Fort Belvoir, VA12 mi63 minS 410.00 miA Few Clouds81°F64°F58%1013.5 hPa
Gaithersburg - Montgomery County Airport, MD21 mi65 minW 9 G 1510.00 miPartly Cloudy79°F62°F56%1016 hPa
Washington/Dulles International Airport, DC, VA22 mi69 minWNW 1210.00 miMostly Cloudy80°F59°F49%1013 hPa
Fort Meade / Tipton, MD22 mi70 minN 010.00 miMostly Cloudy75°F64°F69%1013.9 hPa

Wind History from DCA (wind in knots)
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
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
Last 24hrE9NE5NE6NE6NE5E5E6NE7NE10NE7E4CalmNE3NE4NE3NE5NE4CalmCalmSE4SE4E3SE56
1 day agoE4E6E4E5E3E5E4NE5NE5NE8NE4E3NE3NE4N3NE7NE6CalmE6E8E9E6SE3NE8
2 days agoNW14
G22
W16
G24
NW9
G19
NW11
G19
N8N9N4N3CalmSW3N3CalmCalmS3SE4SW3CalmS3CalmCalmCalmNE5NE6NE4

Tide / Current Tables for Washington, Potomac River, D.C.
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Washington
Click for Map
Mon -- 05:45 AM EDT     Sunrise
Mon -- 06:17 AM EDT     0.18 feet Low Tide
Mon -- 09:50 AM EDT     Moonrise
Mon -- 11:31 AM EDT     3.54 feet High Tide
Mon -- 07:06 PM EDT     -0.02 feet Low Tide
Mon -- 08:25 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.12.621.40.90.50.20.312.133.53.53.12.51.91.30.70.2-00.21.12.12.8

Tide / Current Tables for Bladensburg, Anacostia River, Maryland
   EDIT      (on/off)   Help   One Week of Data
Bladensburg
Click for Map
Mon -- 05:45 AM EDT     Sunrise
Mon -- 06:42 AM EDT     0.21 feet Low Tide
Mon -- 09:50 AM EDT     Moonrise
Mon -- 12:02 PM EDT     3.75 feet High Tide
Mon -- 07:31 PM EDT     -0.02 feet Low Tide
Mon -- 08:25 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.33.12.51.81.20.70.30.20.71.72.83.53.83.532.31.610.50.10.10.71.72.6

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 (15,3,4,5)
      (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.