Sunday, April22, 2018 L-36.com


Marine Weather and Tides
Washington, DC

Version 3.4
What's New / NOTES
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.
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.

Sunrise 6:19AMSunset 7:53PM Sunday April 22, 2018 5:49 PM EDT (21:49 UTC) Moonrise 11:06AMMoonset 12:54AM Illumination 51% 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- 433 Pm Edt Sun Apr 22 2018
Rest of this afternoon..SE winds 10 kt. Waves 1 ft.
Tonight..SE winds 5 kt. Waves less than 1 ft.
Mon..SE winds 10 to 15 kt. Waves 1 ft.
Mon night..SE winds 5 to 10 kt. Waves 1 ft. Rain likely.
Tue..E winds 5 to 10 kt. Waves 1 ft. Rain.
Tue night..E winds 5 to 10 kt. Waves 1 ft. Rain.
Wed..NW winds 5 to 10 kt. Waves 1 ft. Rain in the morning, then showers likely through the night. A chance of showers after midnight.
Thu..SE winds around 5 kt. Waves 1 ft. A chance of showers.
ANZ500 433 Pm Edt Sun Apr 22 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will remain centered over the great lakes region through tonight before moving off the new england coast Monday. An area of low pressure over the deep south will approach the region mid week. Small craft advisories may be needed Tuesday.

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 221859
afdlwx
area forecast discussion
national weather service baltimore md washington dc
259 pm edt Sun apr 22 2018

Synopsis
High pressure over the great lakes will slowly move east into
the northeast u.S. Tonight. This high will move offshore
Monday. A low pressure system currently over the lower
mississippi valley will bring unsettled weather to the region
Monday night through Wednesday. Another storm system may impact
the region at the end of the week.

Near term through Monday
Latest surface analysis depicts high pressure centered over the
eastern great lakes, with an extension southeast to a second
center east of norfolk in the western atlantic. There is a weak
surface trough extending over the region between these two
centers, and that is helping focus a bit of cloud development
this afternoon. There is also an upper level trough crossing the
region. Thanks to the forcing from these two features, its
still not impossible a few sprinkles or a shower pop up, most
likely over western va eastern wv, but odds are very low, less
than 25 percent. Otherwise, dry weather will be the rule for the
remainder of today and tonight. In fact, as the trough passes
southeast away from the region, clouds should generally decrease
overnight, but with dew points now comfortably above freezing,
we should also stay comfortably above freezing, with lows mostly
in the 40s.

On Monday, the high pressure system will shift eastward off the
coast of new england, while low pressure over the lower
mississippi valley at present will migrate northeast towards
central tennessee. As this happens, isentropic lift and moisture
advection will increase with continued southeast flow from the
atlantic, and rain is likely to start breaking out from
southwest to northeast over west central virginia. However,
most of the region should remain dry through sunset, but with
increasing clouds. Despite the southeasterly flow, temperatures
should generally remain as mild as today, or perhaps moderate a
tad further, with 60s common. Coolest readings will be in west-
central va where greater cloud cover and the threat of late-day
rain will hold temps down.

Short term Monday night through Tuesday night
Closed low over western tennessee early Monday night will
migrate east and north into kentucky through Tuesday, finally
opening back up into a shortwave trough Tuesday night as it gets
punted eastward more rapidly thanks to another shortwave droping
southeast across the northern plains. In response to this,
surface low pressure over the tennessee valley will start to
transfer to a new low in the carolinas on Tuesday. This second
low will move northeastward up the coast Tuesday night and
Wednesday. Isentropic lift, upper divergence, fgen and moisture
advection, combined with upslope low level flow from the
southeast, should provide adequate forcing for a decent dose of
rainfall. The question which we are stuck with is: just how
heavy? Many areas had pretty significant rain last Monday, but
it has now been about a week, and will be 8 days past on
Tuesday, so while soils are still more moist than they were
before Monday's rain, they have dried out a bit, and rivers have
also gone down. Right now, guidance is fluctuating a bit with
regards to how much rain will fall, but best estimate places
most of the region in the 1-2 inch range. Locally higher amounts
may result in isolated flooding, but confidence is not high
since the surface low should stay southeast of the region,
potentially limiting the convective elements. Thus, will hold
off on posting any mention of flooding in the hwo for the time
being, though it is noted that wpc has placed the region in a
marginal risk of excessive rainfall.

With the passage of the low pressure and accompanying clouds and
rain, temperatures Monday night through Tuesday night should not
fluctuate much, with 40s for lows Monday night, and temperatures
mostly in the 50s Tuesday and Tuesday night.

Long term Wednesday through Sunday
Low pressure will be moving northeast away from the area
Wednesday morning, leaving a chance for some residual showers in
its wake. Another quick moving shorwave will move through
Wednesday evening into Thursday morning. Some showers will be
possible with this system as well, especially Wednesday night.

Temperatures Wednesday will be below average, thanks to the
cloud cover and precipitation expected over the area.

Weak high pressure will move into the region in the wake of
this system on Thursday into Thursday night, bringing drier
weather into the forecast again, but temperatures remain below
normal.

A lot of uncertainty for Friday's forecast at this time. One
thing that seems consistent among all guidance, is that a
shortwave will move across the southeast late Thursday into
early Friday. This shortwave spawns a surface low somewhere in
the southeast in that same time period. The uncertainty comes
with determining where exactly this system moves, and how strong
it will be. Model guidance has been very jumpy with this
system, thus not giving a clear pattern to run with. On one
hand, you have the european, which slides this system off the
coast and keeps precipitation chances here very low. However,
both the canadian and GFS want to bring the low up the coast,
bringing precipitation chances to the area on Friday. These
models differ from one another in terms of strength as well,
with the GFS phasing the shortwave with the main trough axis,
thus bringing a stronger system to the area, while the canadian
does not phase the systems, resulting in a weaker coastal low,
and lesss precipitation. The GFS had been more alligned with the
european the past few runs, so going to go with a more
intermediate approach and say that we will see some impact from
a coastal low, but not thinking it will be as strong as the
latest GFS suggests. The bottome line is, precipiation is
possible Friday and temperatures will greatly depend on the
evolution of the aformentioned surface low, but thinking we will
be below average once again.

Another low pressure system looks to swing through areas along
the canadian northeastern u.S. Border on Friday night into
Saturday. A cold front associated with this system looks to move
through the area on Saturday, bringing another chance for
precipitation. Model guidance has backed off a bit on the
strength of ths front, but some light precipitation is certainly
possible. The time of frontal passage will determine how warm
we can manage to get on Saturday, but with lingering clouds from
Fridays system, and cluods associated with the aformentioned
front, temperatuers will probably remain at, or slightly below,
average.

Aviation 18z Sunday through Friday
Vfr all termanals through late Monday, though CIGS may start
lowering towards MVFR across the region by then, especially at
cho. Winds mostly from the southeast, but light until Monday
afternoon, when the gradient between the high departing and the
low approaching will increase the southwesterly flow to 10-20
knots.

Sub-vfr likely by late Monday night through Tuesday night all
terminals, with intervals of ifr possible thanks to rain, mist
and low cigs. Winds shifting from southeast to north by late
Tuesday night.

Clouds will stick around for much of the day on Wednesday sub-
vfr condionts possible duruing this time. Conditions should
clear toVFR by Thursday during the late mornign to early
afternoon hours.

Marine
Winds mostly sub SCA thru Monday morning, though some gusts to
around 20 knots thanks to southeasterly channelling are
occurring at present over the lower and middle potomac. Don't
think they last beyond the next two hours, but they could
approach SCA limits. Overnight, the winds there should
definitely relax.

Sca up for lower potomac and middle chesapeake on Monday
afternoon and night as southeasterly flow ahead of approaching
low increases. This could also cause channeling which might
result in SCA further north into the middle potomac, but will
hold on that for now. SCA may expand to all zones on Tuesday as
low approaches and winds shift to east and then perhaps
northeast, finally turning north and diminishing later Tuesday
night as the low passes. Note that the southeastern waters we
cover, most likely the middle bay, could actually become
southerly if the low passes to the north of those areas. Rain
and fog will be a concern as well during this period.

As the storm system from Tuesday exits Wednesday morning, some
gusty winds are possible across the marine areas, with sca
criteria winds possible during that time. Gusty winds also
possible Thursday morning, but not looking as strong as on
Wednesday at this time.

Hydrology
While we had significant rain a week ago, its been pretty dry
since then. That said, 1-2 inches of rain looks likely across
the region Monday night through Wednesday, which could
exacerbate hydrology issues and cause significant river and
stream rises, potentially up to flood stages. Will be closely
monitoring this for potential need of any flood watches over the
next day or so.

Tides coastal flooding
As low pressure approaches the waters from the southeastern
u.S. Late Monday into Tuesday, a persistent onshore flow will
develop. This will yield increasing tidal anomalies, and the
possibility of coastal flooding toward the middle part of the
work week.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory from 1 pm Monday to 6 am edt Tuesday for
anz534-537-543.

Synopsis... Rcm
near term... Rcm
short term... Rcm
long term... Cjl
aviation... Rcm cjl
marine... Rcm cjl
hydrology... Rcm
tides coastal flooding... Rcm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 1 mi50 min ESE 4.1 G 8.9 65°F 54°F1026.9 hPa (-1.2)
BSLM2 - Chesapeake Bay, MD 19 mi140 min SSE 8 64°F 1028 hPa39°F
APAM2 - 8575512 - Annapolis, MD 30 mi50 min 61°F 1027.3 hPa (-1.2)
TPLM2 - Thomas Point, MD 31 mi50 min S 7 G 8 56°F 54°F1028.7 hPa (-1.3)43°F
FSNM2 35 mi50 min ESE 8 G 8.9 60°F 1027.2 hPa (-1.4)
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 35 mi50 min ESE 8 G 8.9 60°F 1027.5 hPa (-1.5)
CPVM2 35 mi50 min 56°F 44°F
BLTM2 - 8574680 - Baltimore, MD 35 mi50 min S 5.1 G 8 62°F 53°F1027.1 hPa (-1.5)
NCDV2 39 mi50 min ESE 17 G 20 59°F 60°F1026 hPa (-1.3)
44062 - Gooses Reef, MD 40 mi40 min SSW 9.7 G 12 55°F 1028.3 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 47 mi50 min N 5.1 G 5.1 58°F 54°F1027.8 hPa (-1.5)
COVM2 - 8577018 - Cove Point LNG Pier, MD 48 mi50 min S 14 G 16 54°F 1028.4 hPa (-1.5)

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA2 mi58 minSE 910.00 miOvercast64°F41°F43%1027 hPa
College Park Airport, MD9 mi73 minSE 1010.00 miFair64°F38°F40%1027.1 hPa
Camp Springs / Andrews Air Force Base, MD9 mi54 minE 12 G 1810.00 miMostly Cloudy63°F35°F36%1027.5 hPa
Fort Belvoir, VA14 mi54 minESE 610.00 miMostly Cloudy67°F40°F39%1026.7 hPa
Fort Meade / Tipton, MD20 mi74 minE 1110.00 miPartly Cloudy63°F37°F39%1028.1 hPa
Gaithersburg - Montgomery County Airport, MD21 mi54 minESE 610.00 miPartly Cloudy64°F41°F43%1030.2 hPa
Washington/Dulles International Airport, DC, VA23 mi58 minSE 810.00 miOvercast64°F42°F45%1026.1 hPa

Wind History from DCA (wind in knots)
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Last 24hrS6S7S4SW3S3S5S3S4S5S6S6S5S5S4E3CalmNE65E11
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1 day agoN16NW15
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NW11NW11N6NW9NW6NE10NE9NE8NE5NE5NE4E3CalmCalmCalmE5NE5N8NE6SE5E5SE4
2 days agoNW21
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Tide / Current Tables for Washington, Potomac River, D.C.
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Washington
Click for Map
Sun -- 01:42 AM EDT     2.97 feet High Tide
Sun -- 01:53 AM EDT     Moonset
Sun -- 06:21 AM EDT     Sunrise
Sun -- 08:36 AM EDT     0.39 feet Low Tide
Sun -- 12:06 PM EDT     Moonrise
Sun -- 01:52 PM EDT     3.28 feet High Tide
Sun -- 05:46 PM EDT     First Quarter
Sun -- 07:51 PM EDT     Sunset
Sun -- 09:33 PM EDT     0.26 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.42.932.72.21.61.10.70.40.40.81.72.63.13.33.12.621.510.60.30.30.8

Tide / Current Tables for Bladensburg, Anacostia River, Maryland
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Bladensburg
Click for Map
Sun -- 01:53 AM EDT     Moonset
Sun -- 02:13 AM EDT     3.15 feet High Tide
Sun -- 06:21 AM EDT     Sunrise
Sun -- 09:01 AM EDT     0.44 feet Low Tide
Sun -- 12:05 PM EDT     Moonrise
Sun -- 02:23 PM EDT     3.47 feet High Tide
Sun -- 05:46 PM EDT     First Quarter
Sun -- 07:51 PM EDT     Sunset
Sun -- 09:58 PM EDT     0.30 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.22.93.132.621.40.90.60.40.61.32.33.13.43.432.41.81.30.80.50.30.6

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 (17,4,5,8)
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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.