Saturday, April29, 2017 L-36.com


Marine Weather and Tides
Woodburn, VA

Version 3.4
What's New / NOTES
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.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 6:10AMSunset 8:01PM Saturday April 29, 2017 11:19 PM EDT (03:19 UTC) Moonrise 8:03AMMoonset 10:44PM Illumination 17% 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 Pm Edt Sat Apr 29 2017
Rest of tonight..E winds 5 kt. Waves less than 1 ft. A slight chance of tstms. A chance of showers. Patchy fog with vsby 1 to 3 nm.
Sun..SE winds 5 to 10 kt. Waves 1 ft. Patchy fog. Vsby 1 to 3 nm.
Sun night..S winds 5 to 10 kt. Waves 1 ft.
Mon..S winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft. A chance of showers and tstms.
Mon night..SW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft. Showers and tstms likely.
Tue..SW winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft.
Tue night..W winds 5 to 10 kt. Gusts up to 20 kt in the evening. Waves 1 ft.
Wed..NE winds 5 to 10 kt. Waves 1 ft. A chance of rain through the night.
Thu..SE winds 5 kt. Waves less than 1 ft. Rain likely. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 1032 Pm Edt Sat Apr 29 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A backdoor cold front will move into the area from the north and east tonight before stalling over the waters Sunday. A stronger cold front will approach from the west Monday before passing through Monday night. A reinforcing cold front will pass through the waters Tuesday and high pressure will build overhead for Wednesday. Low pressure may impact the waters late next week. A small craft advisory will likely be needed for the waters Monday and Tuesday.

7 Day Forecast for Marine Location Near Woodburn, VA
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location: 38.83, -77.23     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 300204
afdlwx
area forecast discussion
national weather service baltimore md/washington dc
1004 pm edt Sat apr 29 2017

Synopsis
A front will sag south into the area through early
Sunday... Before lifting north as a warm front late Sunday. A
cold front will then cross the mid-atlantic Monday night. A
secondary cold front will push southeast Tuesday night. Low
pressure from the tennessee valley will head toward the mid-
atlantic Thursday and Friday.

Near term /until 6 am Sunday morning/
Guidance has consistently overdone convection today. While there
are still suggestions of thunderstorms developing as the
backdoor front drops down overnight, have overall cut pops
somewhat, though still maintain chance showers and slight chance
thunder for a descent portion of the region. That having been
said, if little to nothing occurs, would not be shocked, but
there remains plenty of instability out there, which if
triggered could still result in thunderstorms.

Low clouds and reduced visibility remain an issue overnight,
with low clouds more of a threat north of the front, and reduced
vis from fog an issue more likely to the south. Lows will be in
the 60s for most areas.

See climate section for record information.

Short term /6 am Sunday morning through Monday night/
Backdoor front will likely stall out across the area on Sunday
and be slow to lift back north. At the minimum, this results in
a very tricky temperature forecast with 60s to the north and
upper 80s to the south. The boundary will snake back north over
the mountains, and this will be the most likely place for
instability to combine with terrain forcing to produce a few
thunderstorms during the afternoon. Shear will still be strong
enough that gusty winds could be a threat with stronger storms.

Absent of other forcing, these storms should end quickly with
sunset. Temperatures will once again remain in the 60s
overnight.

On Monday, a deep low pressure system will work from the plains
to the great lakes, which will drag a cold front toward the
forecast area (after ensuring the warm front lifts back to the
north). Timing of the front (or prefrontal trough which could
be what actually initiates convection), appears slightly slower,
but the focus remains on the afternoon and evening, with rain
quickly departing after midnight. Shear will remain strong, but
instability should be lower, with hints of a lingering wedge
over the region. The result may be linear storms which pose a
locally gusty wind threat. Given slower timing and potential for
lingering wedge/marine influence, best chance of severe would
appear to be west of the metros. Highs likely reach the upper
70s to 80s, with lows Monday night falling into the 50s to lower
60s.

Long term /Tuesday through Saturday/
Weak high pressure will build in behind the cold front Tuesday.

A gusty westerly breeze will usher in drier air. Temperatures
will not be as warm as recent days. As the high moves east, a
secondary cold front will move across the region from the
northwest Tuesday night. This front should be a dry front. The
front could sag into the carolinas Tuesday night before starting
to move northward as a warm front on Wednesday.

A low pressure system is expected to develop along the western
end of the warm front over the lower mississippi valley
Wednesday night and early Thursday. We introduce a slight chance
of showers or a rumble of thunder Wednesday night with a higher
chance to likelihood of encountering showers and thunderstorm
Thursday through early Friday.

At the tail-end of an associated cold front with the storm
system, another storm system could develop and deepen over the
interior southeast u.S. Friday and Friday night. The chance of
showers and thunderstorms will linger during the period.

Temperatures will also be closer to normal Friday and Friday
night.

Brief high pressure could build into the mid-atlantic region
Saturday ahead of a cut-off low pressure system over the
southeast u.S. Dry conditions will be follow by increasing
clouds later in the day then a chance of showers Saturday night.

Aviation /02z Sunday through Thursday/
At the moment,VFR conditions exist across the area with gusty
s-sw winds as high pressure to the southeast exerts its
influence. Have removed mention of thunder from tafs since odds
now appear significantly lower than earlier, but the chance for
a storm is not zero overnight as a backdoor cold front slides
south across the area, which could still trigger something given
the unstable air mass in place.

Winds become NE to E behind the front, and some low clouds
and/or light fog could develop. Uncertain if front reaches cho.

While guidance indicates ifr potential, have limited to MVFR
for now.

Front likely bisects area on Sunday, with low clouds potentially
persisting into the afternoon. Thunderstorm development may be
limited to mrb vicinity. Gusty south winds develop Monday ahead
of cold front. Showers/storms will likely affect the area during
the late afternoon and evening, with the cold front moving east
overnight.

Vfr conditions Tuesday through Wednesday night. Winds west-
southwest 10 to 15 knots Tuesday, west 5 to 10 knots Tuesday
night, becoming light and variable Wednesday, and northeast 5 to
10 knots Wednesday night. Conditions deteriorate on Thursday as
low pressure moves toward the area.

Marine
Thunderstorm potential has lowered significantly, but a stray
storm could still develop overnight as backdoor front slides
south into the unstable air mass. The front will stall out
across the waters late tonight and Sunday with east winds north
and southerly to the south. Winds may approach SCA criteria
across the far southern waters on Sunday. Think thunderstorms
chances are fairly low on Sunday. Gradient increases Sunday
night into Monday, with SCA likely all waters on Monday.

Potentially gusty showers and storms will arrive ahead of a cold
front Monday evening. SCA conditions will continue behind the
front.

Small craft advisories likely continue into Tuesday before
abating Tuesday night into Wednesday. Winds west- southwest 10
to 15 knots Tuesday, west 10 knots Tuesday night, becoming
northwest 5 to 10 knots Wednesday, and northeast 5 to 10 knots
Wednesday night.

Tides/coastal flooding
An onshore flow will develop Sunday as a backdoor cold front
stalls overhead. A stronger cold front will approach from the
west Monday before passing through Monday night. Southerly winds
will strengthen ahead of the front during this time. Elevated
water levels are expected Sunday due to the onshore flow and
minor tidal flooding is possible for sensitive areas Monday into
Monday night as the southerly flow strengthens.

By the end of the week though, a coastal low is likely to cause
elevated water levels once again.

Climate
Record highs were set at dca and iad today, but it fell short at
bwi. Record high mins are possible at dca, iad and bwi for the
day if it stays warm enough through 1am (midnight standard
time). Records are less likely Sunday as a backdoor front drops
down. Here are the record highs/warm lows through the weekend:
washington dc...

Saturday 29 april... 91 (in 1974)/68 (in 1956)
Sunday 30 april... 92 (in 1942)/67 (in 1983)
bwi airport...

Saturday 29 april... 91 (in 1974)/67 (in 1956)
Sunday 30 april... 92 (in 1910)/63 (in 1983)
dulles airport..

Saturday 29 april... 87 (in 1996)/62 (in 1996)
Sunday 30 april... 86 (in 2007)/64 (in 1983)
also of note... The warmest night time low at dca in april is 69
degrees. That is being challenged as dca only dropped to 70 this
morning.

Lwx watches/warnings/advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory from midnight Sunday night to 6 am edt
Monday for anz533-541.

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

Synopsis... Ads
near term... Ads
short term... Ads
long term... Klw
aviation... Ads/klw
marine... Ads/klw
tides/coastal flooding... Bjl
climate... Lwx


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 11 mi49 min S 6 G 7 77°F 68°F1017.8 hPa
BSLM2 - Chesapeake Bay, MD 28 mi109 min SSE 5.1 74°F 1018 hPa71°F
NCDV2 37 mi49 min SSW 4.1 G 7 80°F 69°F1018.1 hPa
APAM2 - 8575512 - Annapolis, MD 41 mi49 min 70°F 1018 hPa
TPLM2 - Thomas Point, MD 42 mi79 min S 8.9 G 8.9 69°F 62°F
44063 - Annapolis 42 mi29 min SSW 3.9 G 3.9 67°F 1018.2 hPa
FSNM2 46 mi49 min SSE 6 G 7 82°F 1018.1 hPa
CPVM2 46 mi49 min 68°F 67°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 46 mi49 min ENE 1.9 G 1.9 75°F 1018.1 hPa
BLTM2 - 8574680 - Baltimore, MD 46 mi49 min Calm G 1 76°F 64°F1017.8 hPa
44062 - Gooses Reef, MD 47 mi29 min S 5.8 G 7.8 70°F 1019.3 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA7 mi21 minN 09.00 miFair72°F70°F94%1018.5 hPa
Washington/Reagan National Airport, DC, VA11 mi27 minS 810.00 miPartly Cloudy77°F71°F82%1018.3 hPa
Washington/Dulles International Airport, DC, VA15 mi27 minS 610.00 miA Few Clouds77°F69°F77%1018 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA17 mi23 minS 310.00 mi75°F70°F84%1019.2 hPa
College Park Airport, MD19 mi38 minN 010.00 miFair73°F68°F85%1018.3 hPa
Camp Springs / Andrews Air Force Base, MD19 mi21 minSSW 810.00 miFair77°F69°F79%1018.7 hPa
Quantico Marine Corps Airfield - Turner Field, VA22 mi23 minS 910.00 miFair75°F71°F88%1018.6 hPa

Wind History from DAA (wind in knots)
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Last 24hrSE3CalmCalmCalmNW4CalmS5CalmCalmSW3W4W5S7S10S8S5W5SW4CalmS3CalmCalmCalmCalm
1 day agoSW5S4SW4CalmCalmCalmW3SE3CalmNW5N4CalmS5SE7S8S6SE3
G15
S6SE6SE5SE4CalmCalmCalm
2 days agoCalmCalmCalmCalmCalmCalmCalm--CalmCalmSW5S8S5SE6S7
G16
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G14
S5S6S5S6S5SW6

Tide / Current Tables for Chain Bridge, one mile below, Washington, D.C.
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Chain Bridge
Click for Map
Sat -- 05:49 AM EDT     0.15 feet Low Tide
Sat -- 06:12 AM EDT     Sunrise
Sat -- 09:02 AM EDT     Moonrise
Sat -- 11:22 AM EDT     3.79 feet High Tide
Sat -- 06:43 PM EDT     -0.02 feet Low Tide
Sat -- 07:59 PM EDT     Sunset
Sat -- 11:44 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.12.61.91.20.70.30.20.51.42.53.43.83.73.22.51.71.10.50.1-00.41.42.43

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Sat -- 05:51 AM EDT     0.14 feet Low Tide
Sat -- 06:12 AM EDT     Sunrise
Sat -- 09:02 AM EDT     Moonrise
Sat -- 11:25 AM EDT     3.84 feet High Tide
Sat -- 06:45 PM EDT     -0.03 feet Low Tide
Sat -- 07:59 PM EDT     Sunset
Sat -- 11:44 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.22.71.91.20.70.30.10.41.32.43.43.83.83.32.51.81.10.50.1-00.41.32.33

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 (23,6,7,8)
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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.