Sunday, August20, 2017 L-36.com


Marine Weather and Tides
Dahlgren Center, 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 6:25AMSunset 7:55PM Sunday August 20, 2017 4:04 AM EDT (08:04 UTC) Moonrise 4:03AMMoonset 6:17PM Illumination 4% Phase: Waning Crescent; Moon at 28 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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ANZ536 Tidal Potomac From Indian Head To Cobb Island- 132 Am Edt Sun Aug 20 2017
Overnight..NW winds 5 kt. Waves less than 1 ft. Isolated showers.
Sun..N winds 5 kt. Waves less than 1 ft.
Sun night..SE winds around 5 kt. Waves 1 ft.
Mon..S winds around 5 kt. Waves 1 ft. A chance of showers and tstms.
Mon night..S winds 5 kt. Waves less than 1 ft. A chance of showers and tstms.
Tue..SW winds 5 to 10 kt. Waves 1 ft.
Tue night..SW winds 5 to 10 kt. Waves 1 ft.
Wed..NW winds 5 kt. Waves less than 1 ft. A chance of showers and tstms.
Thu..N winds 5 kt. Waves less than 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 132 Am Edt Sun Aug 20 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will return today. The high will move offshore Monday and a stronger cold front will approach Tuesday before passing through Wednesday. High pressure will build overhead behind this boundary. Small craft advisories will likely be needed Tuesday into Wednesday.

7 Day Forecast for Marine Location Near Dahlgren Center, VA
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location: 38.32, -77.03     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 200750 aaa
afdlwx
area forecast discussion... Updated
national weather service baltimore md washington dc
350 am edt Sun aug 20 2017

Synopsis
High pressure will build overhead today before moving offshore
tonight through Monday. A cold front will approach the area
Tuesday before passing through Wednesday. High pressure will
build in behind the boundary for Thursday through Saturday.

Near term through tonight
Update to add discussion of thunderstorm possibilities in the
marine section...

the upper-level disturbance and weak reinforcing cold front that
caused the convection Saturday night has moved away from the
area. High pressure is building in from the north. A light
northerly flow ahead of the high has allowed for drier
conditions. Patchy fog is still possible since the flow is
light... Especially across central virginia early this morning.

Weak high pressure will continue to build overhead through
midday before moving toward the mid-atlantic coast late in the
day. Most areas will have dry conditions along with sunshine and
lower humidity. However... A light return flow will develop late
today over the shenandoah valley and portions of the potomac
highlands. A surface trough will also develop from daytime
heating... And this may be enough to trigger an isolated shower
or thunderstorm toward evening. Most places should be dry though
since moisture will remain somewhat limited and forcing will be
weak.

The high will will remain along the mid-atlantic coast tonight
and a return flow will develop for most other areas. Increased
moisture and slight isentropic upglide will result in more
clouds and perhaps even isolated showers and thunderstorms.

Forcing should still be weak so any convection appears that it
would be isolated.

Short term Monday through Tuesday night
High pressure will continue to shift offshore Monday and a
southerly flow will strengthen... Allowing for more humid
conditions to return. The increased humidity will cause an
unstable atmosphere and another surface trough is expected to
develop... Acting as the lifting mechanism for isolated to
scattered thunderstorms. High amounts of instability are
possible with dewpoints likely climbing back into the 70s for
many locations. NAM bufkit is showing around 2000-3000 j kg of
mlcape developing in the afternoon. Other guidance has less
instability and it will depend on how quickly dewpoints
increase. For now... The latest forecast leans toward the nam
thinking that a return southerly flow will transport more
moisture from the warm waters nearby this time of year.

Despite weaker shear profiles and weak mid-level lapse rates and
weak forcing... If this instability is realized then strong to
locally severe storms are possible.

For the eclipse... The isentropic upglide that is likely to
bring more clouds Sunday night should gradually weaken Monday
morning. This will allow for breaks of sunshine during the late
morning through the middle afternoon hours. A pop shower or
thunderstorm cannot be ruled out from daytime heating.

However... The most likely scenario for the strong to perhaps
even locally severe storms along with more cloud cover is that
they would hold off until late in the afternoon into Monday
evening. Will have to keep a close eye on this because when
timing convection this far out confidence is low.

High pressure will remain offshore Monday night. Any convection
that does develop should gradually decrease in coverage later
Monday night. More warm and humid conditions are expected with
patch fog.

A cold front will move from the great lakes toward the ohio
valley Tuesday before eventually moving toward our area Tuesday
night. Shear profiles will increase later Tuesday through
Tuesday night as an upper-level trough digs over the great lakes
toward new england. Warm and humid conditions ahead of the
boundary will continue to a southwest flow ahead of the
approaching cold front. A few showers and thunderstorms are
possible... Especially late Tuesday into Tuesday night across
northern and central portions of the CWA closer to the cold
front. Some storms may be strong to severe given the instability
and strengthening shear profiles.

Long term Wednesday through Saturday
A cold front will move across the region Wednesday before moving
offshore Wednesday night. There is a chance for showers and
thunderstorms ahead of and along the front. Temperatures will be
seasonably warm with highs in the middle 80s along and east of the
blue ridge, while highs manage to reach the middle to upper 70s west
in the potomac highlands.

A broad area of high pressure will build in from the northwest
behind the front Wednesday night through Thursday night, ushering
in cooler and drier air. Low temperatures Wednesday night will be
about 10 degrees cooler than previous nights. Thursday's high
temperatures may only top the 80 degree mark in most locations,
while we can expect Thursday night's low temperatures to be about
the same as Wednesday night's low temperatures... In the lower to
middle 60s.

Although high pressure is expected to keep most of our region dry
and comfortable Friday, we can't rule out a pop-up shower or
thunderstorm over the higher elevations along the appalachian front
during the afternoon or early evening.

High pressure should regain control of the entire region overnight
Friday night and Saturday. Dry conditions and seasonably cool
temperatures should continue across the region.

Aviation 08z Sunday through Thursday
Vfr conditions are most likely through Tuesday... But patchy fog
is possible during the early morning hours each day. Isolated
showers and thunderstorms are possible tonight through Tuesday.

Some storms may produce gusty winds... Mainly during the
afternoon and evening hours each day.

A cold front will approach the terminals Tuesday night. More
showers and thunderstorms are possible. A few storms may be
strong to severe.

Vfr conditions Wednesday through Thursday night. There could be
brief periods of subvfr conditions at any one of the terminals
due to shower and thunderstorm activity ahead of and along the
cold front Wednesday. Winds southwest 5 to 10 knots Wednesday
morning, becoming northwest around 10 knots with gusts 15 to 20
knots Wednesday afternoon through Wednesday night. Winds
becoming north 5 to 10 knots Thursday and Thursday night.

Marine
High pressure will build over the waters today before shifting
toward the mid-atlantic coast tonight. The high will move
offshore Monday through Monday night and a cold front will
approach the waters Tuesday through Tuesday night. The boundary
will pass through Wednesday and high pressure will build over
the waters for late next week. A small craft advisory may be
needed for portions of the waters Monday night through Wednesday
night.

Isolated thunderstorms are possible over the waters late
tonight through Monday morning. Scattered thunderstorms are
possible Monday afternoon and evening. Some storms may produce
gusty winds... Especially later Monday into Monday evening. A few
showers and thunderstorms are possible later Tuesday into
Wednesday ahead of a cold front as well... And some of these
storms have the potential to be strong to locally severe.

Tides coastal flooding
Elevated water levels continue early this morning. The flow has
turned offshore and it will remain offshore through midday... But
it will be light. A light onshore flow is expected to develop
late today and tonight.

A southerly flow will strengthen a bit for later Monday through
early Wednesday ahead of a cold front. Minor tidal flooding is
possible for sensitive areas near high tide during the
overnight and morning hours both days.

A stronger offshore flow is expected behind the cold front later
Wednesday.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... None.

Synopsis... Bjl
near term... Bjl
short term... Bjl
long term... Klw
aviation... Bjl klw
marine... Bjl klw
tides coastal flooding... Bjl


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
NCDV2 0 mi52 min Calm G 1.9 73°F 83°F1014.8 hPa
PPTM2 - 8578240 - Piney Point, MD 29 mi46 min NE 6 G 6
SLIM2 - 8577330 - Solomons Island, MD 31 mi52 min NNW 2.9 G 4.1 75°F 82°F
COVM2 - 8577018 - Cove Point LNG Pier, MD 35 mi46 min NNW 5.1 G 7 76°F 1016.3 hPa
BSLM2 - Chesapeake Bay, MD 36 mi154 min Calm 65°F 1015 hPa64°F
44062 - Gooses Reef, MD 36 mi34 min WNW 3.9 G 5.8 77°F 1016.3 hPa
LWTV2 - 8635750 - Lewisetta, VA 37 mi46 min WSW 2.9 G 2.9 77°F 83°F1015.5 hPa
WASD2 - 8594900 - Washington, DC 38 mi46 min WNW 1.9 G 5.1 73°F 82°F1015.5 hPa
44042 - Potomac, MD 42 mi34 min NNE 1.9 G 3.9 80°F 1014.9 hPa

Wind History for Piney Point, MD
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Quantico Marine Corps Airfield - Turner Field, VA19 mi68 minNW 510.00 miFair71°F69°F94%1016.2 hPa
Fredericksburg, Shannon Airport, VA23 mi69 minN 310.00 miFair72°F65°F82%1015.9 hPa
Stafford, Stafford Regional Airport, VA23 mi69 minWNW 310.00 miFair65°F65°F100%1017.6 hPa

Wind History from NYG (wind in knots)
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Last 24hrNW3NW6CalmNW4NE3N7NW5NW8CalmNW5S4S6S6S8S9SW3CalmNW6NW10N4E4NW5NW5NW6
1 day agoSW8SW9SW6SW5S4S10S9S11S9S11S11S9W22
G31
SE6NW10S10E5S7S9SW10W4NW8N8NW3
2 days agoCalmCalm----S8S7S8S6----SE11SE7S13S15S12S9S10S7S6S9S10SW6SW4S10

Tide / Current Tables for Dahlgren, Upper Machodoc Creek, Virginia
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Dahlgren
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Sun -- 02:23 AM EDT     2.28 feet High Tide
Sun -- 05:03 AM EDT     Moonrise
Sun -- 06:27 AM EDT     Sunrise
Sun -- 08:51 AM EDT     0.24 feet Low Tide
Sun -- 02:43 PM EDT     2.00 feet High Tide
Sun -- 07:17 PM EDT     Moonset
Sun -- 07:54 PM EDT     Sunset
Sun -- 09:00 PM EDT     0.11 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.622.32.221.61.10.60.30.20.40.81.21.71.921.81.510.60.20.10.20.6

Tide / Current Tables for Colonial Beach, Potomac River, Virginia
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Colonial Beach
Click for Map
Sun -- 01:56 AM EDT     2.27 feet High Tide
Sun -- 05:03 AM EDT     Moonrise
Sun -- 06:27 AM EDT     Sunrise
Sun -- 08:24 AM EDT     0.26 feet Low Tide
Sun -- 02:16 PM EDT     1.99 feet High Tide
Sun -- 07:17 PM EDT     Moonset
Sun -- 07:54 PM EDT     Sunset
Sun -- 08:33 PM EDT     0.13 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.82.22.32.11.81.40.90.50.30.30.611.41.821.91.71.30.80.40.20.20.40.9

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 (4,6,7,8)
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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.