Tuesday, November20, 2018 L-36.com


Marine Weather and Tides
Stafford Courthouse, VA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 6:56AMSunset 4:55PM Tuesday November 20, 2018 3:29 PM EST (20:29 UTC) Moonrise 3:44PMMoonset 3:52AM Illumination 95% Phase: Waxing Gibbous; Moon at 13 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- 1238 Pm Est Tue Nov 20 2018
.small craft advisory in effect until 6 pm est this evening...
.small craft advisory in effect Wednesday afternoon...
This afternoon..NW winds 10 kt with gusts to 20 kt. Waves 1 ft.
Tonight..NW winds 5 to 10 kt. Waves 1 ft.
Wed..W winds 5 to 10 kt. Gusts up to 20 kt in the late morning and afternoon. Waves 1 ft.
Wed night..NW winds 5 to 10 kt. Waves 1 ft.
Thu..N winds 5 to 10 kt. Waves 1 ft.
Thu night..NE winds 5 kt. Waves less than 1 ft.
Fri..E winds around 5 kt. Waves 1 ft.
Sat..E winds 5 to 10 kt...becoming N after midnight. Waves 1 ft. Rain likely.
ANZ500 1238 Pm Est Tue Nov 20 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will briefly build in tonight before a more potent cold front will move through the waters late Wednesday and Wednesday night. Strong canadian high pressure will build over the waters for the remainder of the work week. Small craft advisories may be required for portions of the waters Wednesday night through Thursday.


7 Day Forecast for Marine Location Near Stafford Courthouse, VA
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location: 38.41, -77.41     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 201907
afdlwx
area forecast discussion
national weather service baltimore md washington dc
207 pm est Tue nov 20 2018

Synopsis
High pressure will nudge into the area tonight, before a strong
cold front crosses the region by Wednesday night. High pressure
of canadian origin will build to our north for the remainder of
the work week before another low pressure system approaches the
area over the weekend.

Near term through tonight
Northwest flow from cold advection supporting some wind gusts in
the 20s (mph). Clouds have been slow to erode thus far, but the
atmosphere dries out considerably by 00z, so feel comfortable
with clearing skies by this evening.

In the mountains, only webcams showing snow along just west of
the highest terrain. Surrounding the peaks, temperatures still
in the mid 30s (or higher). Thus snow accumulation should be
localized, and at this point temporally limited.

As high pressure nudges east tonight, am looking for a mostly
clear night outside of the appalachians (the mountains will
still be mostly cloudy). With decoupling winds, temperatures
will be considerably cooler... Subfreezing outside of the major
downtowns along the bay.

Short term Wednesday through Thursday night
In absence of any synoptically forced feature, Wednesday should
be rather benign, albeit a few degrees cooler given cold
advection. Shortwave energy crossing the northeast will push a
reinforcing cold front through late Wednesday afternoon or
Wednesday evening, which will kick up winds and allow arctic air
to funnel across the northeast. It may be a struggle for
temperatures to rise above freezing on Thursday, especially
across northern maryland.

Given its continental origins, there isn't much moisture
associated with the front, and forcing limited as well, so do
not expect the frontal passage to be marked by precip. And in
the mountains, an inversion around 850 mb will be too
strong low... Limiting snow growth. Am carrying just chance snow
showers for Wed afternoon evening.

Long term Friday through Tuesday
A upper level ridge will be in place over our region through most of
Friday. A surface low at the surface will slowly start to shift
northeastward out of the region. Cool and dry weather will continue
through the early parts of Friday. Winds will become southerly as
the surface high moves northeastwards. The southerly flow will help
transport some slightly more moist air into the region. The 00z euro
and the 12z GFS both agree that the surface high will settle over
new england and the the new england coast.

Saturday into Sunday, a frontal boundary will approach from the west
with a upper level trough at 500mb. Both GFS and euro agree that
precipitation will start to affect the western parts of our cwa
early Saturday morning. The models start to differ on how the
surface low that forms over the panhandle of florida moves
northward. The euro keeps the track closer to the coast while the
gfs takes the main low out to sea through the carolinas.

Precipitation will be likely on Saturday and possibly into the early
parts of Sunday. The big unknown for this system will be the type
of precipitation especially along our mountainous zones. The 850
temperatures hover in the one to 3 degree range especially over the
higher elevations while euro surface temperature output suggest near
or slightly below freezing at the surface. This would be freezing
rain to a winter mix for most areas around the blue ridge and
possibly as far east as i-95. The canadian model shows a similar
solutions with warm air aloft and could air at the surface. High
pressure to the northeast could help dam in cold air over the
region. We will be tracking the type of precipitation for Saturday
morning and into Sunday. Most precipitation is expected to be out of
the region by Sunday morning. Weak high pressure will briefly build
into the region on Sunday.

On Monday, another frontal boundary is forecast to affect our
region. The air mass for this system looks to be much warmer which
suggests mainly a rain event. With temperatures warming back into
the 50s and the forcing from the boundary could lead to some
thunderstorm development but it is too early to tell.

Aviation 19z Tuesday through Sunday
Vfr flight conditions will prevail through the valid taf
period. Northwest flow will also dominate, with a lull this
evening as winds decouple. A reinforcing cold front will kick
winds back up Wed late aftn eve, but forcing seems to be too
weak limited for any precip. It -will- be much cooler for wed
night and thu.

On Friday, high pressure will slowly shift out of the region. Skies
will remain mostly clear on Friday with winds becoming southerly.

Clouds will build into the region Friday evening.VFR conditions
expected.

Saturday, a frontal boundary will affect the region. Precipitation
will be likely with a wintry mix possible west of i-95 with the
best chances over the higher elevation areas. Skies will be mostly
cloudy with winds mainly out of the south. Subvfr conditions
likely.

Marine
Northwest flow behind a cold front have brought winds into the
range of small craft advisories this afternoon. Winds will
slowly decouple tonight, with a bit of a lull Wed morning. An
arctic boundary Wed pm will support more small craft winds.

Current advisory Wed afternoon likely will need to be extended
into Wed night, and possibly into Thu morning for the open
waters of the mid bay. Northwest flow will gradually decrease
during thanksgiving.

On Friday, wind will be out of the south with weak winds aloft. This
suggest that small craft advisories won't be needed at this time.

Saturday, precipitation will be likely with winds possibly reaching
over 20mph. Small craft advisories will likely be needed.

Climate
Unseasonably cold weather is looking increasingly likely to
briefly take hold of the region on thanksgiving. Daytime
temperatures are likely to stay in the 30s, and it could be the
coldest thanksgiving in over 20 years, depending on the readings
at midnight. Here are the benchmark readings to compare this
thanksgiving to:
washington dc area
year high elapsed
2017 47 1 year
2013 40 5 years
2000 38 18 years
1996 35 22 years
1930 30 88 years
the high has not been lower than 30 on thanksgiving since
official temperature record keeping began in 1872.

Baltimore md area
year high elapsed
2017 44 1 year
2013 38 5 years
2000 37 18 years
1996 33 22 years
1930 31 88 years
the high has not been lower than 31 on thanksgiving since
official temperature record keeping began in 1872.

Rainfall totals continue to creep upward, with baltimore setting
the annual record already. Here are the current rankings for
wettest year on record (through november 18th):
washington dc area (dca)
1. 61.33 inches (1889)
2. 60.83 inches (2003)
3. 60.09 inches (1878)
4. 58.58 inches (2018)
5. 58.17 inches (1886)
weather records for the washington dc area have been kept at
what is now ronald reagan washington national airport (dca)
since 1945. Precipitation records observed downtown extend the
period of record back to 1871.

Baltimore md area (bwi)
1. 63.18 inches (2018)
2. 62.66 inches (2003)
3. 62.35 inches (1889)
4. 58.98 inches (1979)
weather records for the baltimore md area have been kept at
what is now baltimore-washington international thurgood marshall
airport (bwi) since 1950. Precipitation records observed
downtown extend the period of record back to 1871.

Dulles va area (iad)
1. 65.67 inches (2003)
2. 59.17 inches (2018)
3. 59.05 inches (1972)
4. 58.09 inches (1996)
5. 55.43 inches (1979)
weather records have been kept at what is now washington dulles
international airport (iad) since 1960.

Note: all climate data are considered preliminary until
reviewed by the national centers for environmental information
(ncei).

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory until 5 am est Wednesday for anz530>534-
537>543.

Small craft advisory from 10 am to 6 pm est Wednesday for
anz530>532-538>540.

Small craft advisory from 1 pm to 6 pm est Wednesday for
anz533>537-541>543.

Small craft advisory until 6 pm est this evening for anz535-
536.

Synopsis... Ads hts
near term... Hts
short term... Hts
long term... Jmg
aviation... Hts jmg
marine... Hts jmg
climate...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
NCDV2 21 mi47 min NW 11 G 16 53°F 50°F1015 hPa
WASD2 - 8594900 - Washington, DC 38 mi41 min WNW 7 G 17 51°F 46°F1016.4 hPa
BSLM2 - Chesapeake Bay, MD 45 mi119 min NW 8 52°F 1015 hPa34°F
PPTM2 - 8578240 - Piney Point, MD 50 mi47 min NNW 19 G 21

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Stafford, Stafford Regional Airport, VA3 mi34 minNW 17 G 2210.00 miMostly Cloudy55°F37°F54%1017.6 hPa
Quantico Marine Corps Airfield - Turner Field, VA9 mi33 minNNW 1310.00 miOvercast54°F33°F45%1016.6 hPa
Fredericksburg, Shannon Airport, VA10 mi54 minNW 11 G 1710.00 miMostly Cloudy55°F38°F54%1015.6 hPa
Warrenton-Fauquier Airport, VA20 mi54 minNW 14 G 1910.00 miOvercast51°F30°F45%1015.9 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA22 mi33 minNNW 1310.00 miOvercast49°F32°F52%1018.1 hPa

Wind History from RMN (wind in knots)
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Last 24hrSE4SE5SE3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmN4NW7
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NW12N8NW12
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1 day ago----------------------------------------SE3CalmS4SE3
2 days ago------------------------------------------------

Tide / Current Tables for Aquia Creek, Virginia (2)
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Aquia Creek
Click for Map
Tue -- 03:42 AM EST     1.21 feet High Tide
Tue -- 03:51 AM EST     Moonset
Tue -- 06:56 AM EST     Sunrise
Tue -- 09:41 AM EST     0.01 feet Low Tide
Tue -- 03:43 PM EST     Moonrise
Tue -- 04:00 PM EST     1.32 feet High Tide
Tue -- 04:53 PM EST     Sunset
Tue -- 10:28 PM EST     0.04 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.50.81.11.21.210.80.40.2000.10.40.81.11.31.31.210.70.40.20.10.1

Tide / Current Tables for Fredericksburg, Rappahannock River, Virginia
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Fredericksburg
Click for Map
Tue -- 03:52 AM EST     Moonset
Tue -- 04:40 AM EST     2.76 feet High Tide
Tue -- 06:56 AM EST     Sunrise
Tue -- 11:16 AM EST     0.03 feet Low Tide
Tue -- 03:44 PM EST     Moonrise
Tue -- 04:53 PM EST     Sunset
Tue -- 04:58 PM EST     3.02 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.30.91.72.32.72.72.41.91.20.60.200.10.61.52.42.932.82.31.71.10.60.2

Weather Map and Satellite Images
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GOES Local Image of    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 (15,3,4,5)
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Ground Weather Radar Station Sterling, VA
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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.