Wednesday, June20, 2018 L-36.com


Marine Weather and Tides
Washington, DC

Version 3.4
What's New / NOTES
5/20/2018 -- NOAA is having problems with the data feed that I use to draw the graphs. They are aware of the issue and working to resolve it. Sometimes changing the location by about a mile will give a correct graph. 3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.

Sunrise 5:41AMSunset 8:38PM Wednesday June 20, 2018 9:27 AM EDT (13:27 UTC) Moonrise 12:21PMMoonset 12:22AM Illumination 46% Phase: First Quarter Moon; Moon at 7 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- 731 Am Edt Wed Jun 20 2018
Today..SE winds 5 kt. Waves less than 1 ft. Scattered showers and tstms this afternoon.
Tonight..W winds 5 kt. Waves less than 1 ft. Showers and tstms likely.
Thu..N winds 5 kt. Waves less than 1 ft.
Thu night..E winds around 5 kt. Waves 1 ft.
Fri..E winds 5 kt. Waves less than 1 ft. A chance of showers.
Fri night..E winds 5 kt. Waves less than 1 ft. Showers likely.
Sat..W winds 5 to 10 kt. Waves 1 ft. Showers and tstms likely.
Sun..W winds 5 to 10 kt. Waves 1 ft. A chance of tstms. A chance of showers. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 731 Am Edt Wed Jun 20 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will track from west virginia east over the waters along a stalled front through tonight. The front will then drop farther south Thursday as high pressure briefly builds from the ohio valley to new england. The front will then return north as a warm front Friday night into Saturday as the high moves offshore and low pressure moves from the midwest to the great lakes. A small craft advisory may be needed for a portion of the waters Friday into Saturday.

7 Day Forecast for Marine Location Near Washington, DC
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location: 38.89, -77.03     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 201042
afdlwx
area forecast discussion
national weather service baltimore md washington dc
642 am edt Wed jun 20 2018

Synopsis
Low pressure will track from west virginia east over the mid-
atlantic along a stalled front through tonight. The front will drop
farther southward Thursday as high pressure briefly builds from the
ohio valley to new england, then return north as a warm front Friday
night into Saturday. Low pressure will move from the ohio valley to
the great lakes Saturday, then off the new england coast Saturday
night into Sunday bringing a cold front across the mid-atlantic.

Near term through tonight
Cam guidance initiates convection over western maryland and vicinity
around 9 or 10 am. This is where a stalled front will lie, draping
southeastward into central virginia. Showers and thunderstorms
likely expand in coverage late this morning into this afternoon down
the shenandoah valley, near the blue ridge and into the central
virginia piedmont. Coverage should be more scattered east of the
front toward the metros on the cooler stable side of the boundary.

Any thunderstorms will be capable of heavy rain, which may result in
isolated instances of flooding. See hydrology section for details.

Although shear is marginal, ample low-level moisture along and south
of the boundary (mainly SW of the potomac river again) will result
in CAPE sufficient for strong convection capable of isolated
damaging downburst winds. The threat today may be focused near
or a touch further south and west than yesterday, but coverage
is expected to remain similarly isolated, unless convection can
organize into one or more linear segments (as some of the
latest runs of the hrrr 3km NAM nest suggest).

With the front overhead and cloud cover around, high temperatures
today should be several degrees cooler than Tuesday, but still very
warm and muggy especially south of the front. The same holds true
for tonight's low temperatures. Patchy fog potential will be higher
given additional rain wet ground, and light winds.

Short term Thursday through Friday night
The front will push further southward briefly Thursday into Thursday
night as an area of high pressure moves from the ohio valley into
new england. Scattered showers and a few thunderstorms will remain
possible near the boundary of the central shenandoah valley and
adjacent higher terrain Thursday afternoon and evening, with showers
likely re-developing persisting into the overnight over these areas
as low-level moist advection and southeasterly upslope flow ensue.

Another round of showers and a few thunderstorms is likely areawide
Friday into Friday night as the front returns north as a warm front.

See hydrology section for details on the heavy rain threat Friday
into Friday night.

Warm and muggy conditions will continue, but not quite as high as
earlier this week.

Long term Saturday through Tuesday
On Saturday, a closed upper low will be shearing out over the great
lakes while a surface cyclone takes a similar track to the
northeast. A warm front will be draped across the area, with
potential for fairly widespread rainfall to be ongoing or having
just ended. Even though it is summer, this pattern may result in a
bit of a wedge, with uncertainty how quickly northward the warm
front lifts. A wave of low pressure may form along the front to
aid in the process. Assuming the front clears, temperatures
should surge well into the 80s by afternoon. There is some model
disagreement on whether subsidence develops behind the early
wave during the afternoon, or if there is enough influence from
the upper level trough to generate additional showers and
thunderstorms.

The surface cold front will drop southward into the area on
Sunday as low pressure moves toward the canadian maritimes.

While some showers and storms could develop, a westerly flow may
bring in drier air which will limit the chance. Warm and humid
conditions likely continue ahead of the front. An upper level
trough will dive southeastward into new england on Monday. It
does appear that the surface front will be south of the area by
that time, so there is some question how much moisture will be
available in the northwest flow. Will have to hold on to at
least a chance of showers, particularly if a more amplified
solution like the GFS verifies.

There is fairly good model agreement on high pressure building in
from the northwest by Tuesday which will result in less humid
conditions and temperatures near or slightly below normal.

Aviation 12z Wednesday through Sunday
A cold front is stalled from near cumberland md southeast to
fredericksburg va. Showers and thunderstorms are likely to develop
by late morning near mrb, then expand in coverage this afternoon
down the front to near cho. Coverage should be more scattered
further east toward iad dca and especially bwi mtn in more stable
air. Any thunderstorm could result in brief ifr restrictions and
localized gusty winds severe turbulence. A second area of convection
may develop INVOF bwi mtn this evening as low pressure develops on
the front and enhances surface convergence. Winds will be light
today (s around 5 knots) outside of any convection due to a weak
gradient with the front overhead. River bay breezes are likely at
dca mtn respectively given warm air cool water light background flow.

Fog seems more likely tonight mainly near mrb cho given likelihood of
wetter ground and light winds, though broken clouds may prevent more
widespread dense fog. Lower CIGS possible north of the front and
could creep into mrb to mtn late tonight (mainly MVFR). Light se
flow expected.

Most precipitation should stay SW of mrb to cho as the front pushes
southward Thursday, but then precipitation chances increase again as
the front returns north Friday into Friday night.

Sub-vfr clouds and reduced visibility in rain will remain possible
Saturday morning until a warm front lifts to the north. Additional
showers and thunderstorms may develop at times later Saturday
through Sunday as a cold front approaches from the northwest.

Marine
A weak gradient with a cold front stalled near the waters should
result in sub SCA winds through Friday. A wave of low pressure will
ride along the front this evening, sending it further south briefly
on Thursday before returning north by week's end. It is ahead of
this returning warm front that easterly southeasterly flow could
increase to SCA levels for portions of the waters. The lower tidal
potomac river and middle chesapeake bay would be most susceptible.

Small craft advisory conditions in southwest flow will be possible
Saturday after a warm front lifts to the north. A cold front will
gradually drop toward the area Sunday, with a little more
uncertainty in wind speeds and direction by that time. Thunderstorms
will also be possible at times over the weekend.

Hydrology
A cold front is stalled across the mid-atlantic. The best
instability will be pooled near and west of the blue ridge today,
with convection likely initiating by mid to late morning over NW md
and vicinity. These areas have the best potential for repeated
rounds of convection given steering flow most parallel to the
boundary. A more isolated heavy rain threat exists further east.

Coverage should remain more scattered toward the metros into this
evening, when a second area of heavy thunderstorms is possible over
ne md. This is a result of a surface low riding along the front,
increasing low-level moist advection and surface convergence.

Aforementioned front will slide south Thursday before returning
north Friday. A modest low-level jet of 25-30 kts in the 900-800 mb
layer is progged by the majority of the guidance Friday into Friday
night which will advect in more moisture (pwats likely exceed 2
inches by Friday evening). The upslope component will leave eastern
slopes vulnerable to enhanced heavy rain. Elsewhere, numerous
showers and a few embedded thunderstorms seem likely Friday
afternoon and evening as the front begins to lift north.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... None.

Synopsis... Dhof
near term... Dhof
short term... Dhof
long term... Ads
aviation... Ads dhof
marine... Ads dhof
hydrology... Dhof


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 1 mi40 min ESE 1.9 G 4.1 77°F 77°F1012.3 hPa
BSLM2 - Chesapeake Bay, MD 19 mi118 min Calm 58°F 1012 hPa57°F
APAM2 - 8575512 - Annapolis, MD 30 mi40 min 1011.6 hPa
TPLM2 - Thomas Point, MD 31 mi88 min NNE 9.9 G 9.9 73°F 76°F1012.7 hPa (+0.8)60°F
44063 - Annapolis 32 mi28 min NE 5.8 G 7.8 74°F 76°F1 ft1012.4 hPa (+0.5)
FSNM2 35 mi40 min NE 4.1 G 5.1 74°F 1011.9 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 35 mi40 min NNE 4.1 G 5.1 74°F 1011.9 hPa
CPVM2 35 mi40 min 75°F 59°F
BLTM2 - 8574680 - Baltimore, MD 35 mi40 min ENE 4.1 G 5.1 78°F1011.8 hPa
NCDV2 39 mi40 min N 1 G 1.9
44062 - Gooses Reef, MD 40 mi28 min ENE 5.8 G 7.8 75°F 77°F1 ft1012.9 hPa (+1.1)
TCBM2 - 8573364 - Tolchester Beach, MD 47 mi40 min NNE 2.9 G 4.1 75°F 78°F1012.3 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 48 mi40 min NE 5.1 G 6 75°F 1012.4 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA2 mi36 minENE 510.00 miMostly Cloudy77°F60°F56%1012.3 hPa
College Park Airport, MD9 mi51 minN 010.00 miFair74°F59°F60%1012.2 hPa
Camp Springs / Andrews Air Force Base, MD9 mi32 minNE 410.00 miPartly Cloudy75°F61°F64%1012.6 hPa
Fort Belvoir, VA14 mi92 minN 010.00 miA Few Clouds75°F64°F69%1012.4 hPa
Fort Meade / Tipton, MD20 mi52 minE 410.00 miPartly Cloudy72°F60°F69%1012.9 hPa
Gaithersburg - Montgomery County Airport, MD21 mi32 minVar 39.00 miFair75°F60°F60%1015.2 hPa
Washington/Dulles International Airport, DC, VA23 mi36 minN 010.00 miMostly Cloudy74°F61°F64%1012.3 hPa

Wind History from DCA (wind in knots)
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E3N9N8N6N5NW4N4N6N5N6N5N5N4N7NE6NE6NE5NE5
1 day agoS6S10S11S10S12S11S13S10S10S8S8S6S8SW9SW6SW7S7S8S8S7S7S7CalmW5
2 days agoCalmSE3S4S5S5S3S3S5S4S6S5SE6S4S7S7CalmS4CalmS3SE3S3--S4S6

Tide / Current Tables for Washington, Potomac River, D.C.
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Washington
Click for Map
Wed -- 01:22 AM EDT     Moonset
Wed -- 02:14 AM EDT     3.16 feet High Tide
Wed -- 05:42 AM EDT     Sunrise
Wed -- 06:52 AM EDT     First Quarter
Wed -- 09:17 AM EDT     0.26 feet Low Tide
Wed -- 01:20 PM EDT     Moonrise
Wed -- 02:35 PM EDT     3.08 feet High Tide
Wed -- 08:36 PM EDT     Sunset
Wed -- 09:42 PM EDT     0.09 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.32.93.23.12.62.11.510.60.30.41.122.6332.72.21.61.10.60.20.10.6

Tide / Current Tables for Bladensburg, Anacostia River, Maryland
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Bladensburg
Click for Map
Wed -- 01:22 AM EDT     Moonset
Wed -- 02:45 AM EDT     3.35 feet High Tide
Wed -- 05:42 AM EDT     Sunrise
Wed -- 06:52 AM EDT     First Quarter
Wed -- 09:42 AM EDT     0.29 feet Low Tide
Wed -- 01:20 PM EDT     Moonrise
Wed -- 03:06 PM EDT     3.27 feet High Tide
Wed -- 08:36 PM EDT     Sunset
Wed -- 10:07 PM EDT     0.10 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
22.83.23.332.51.91.30.80.40.30.81.72.533.33.12.621.40.80.40.10.3

Weather Map and Satellite Images
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GOES Local Image of Mid-Atlantic    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Baltimore, MD/Washington (9,2,3,4)
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Ground Weather Radar Station Sterling, VA
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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.