Thursday, January18, 2018 L-36.com


Marine Weather and Tides
Mantua, 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 7:22AMSunset 5:16PM Thursday January 18, 2018 8:33 AM EST (13:33 UTC) Moonrise 8:20AMMoonset 6:52PM Illumination 3% Phase: Waxing Crescent; Moon at 2 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- 631 Am Est Thu Jan 18 2018
.small craft advisory in effect until 4 pm est this afternoon...
Today..W winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft.
Tonight..SW winds around 5 kt. Waves 1 ft.
Fri..SW winds around 5 kt. Waves 1 ft.
Fri night..SW winds around 5 kt. Waves 1 ft.
Sat..SW winds around 5 kt. Waves 1 ft.
Sat night..NW winds around 5 kt. Waves 1 ft.
Sun..S winds around 5 kt. Waves 1 ft.
Mon..S winds 5 to 10 kt. Waves 1 ft. Showers likely through the night.
ANZ500 631 Am Est Thu Jan 18 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will move off the north carolina coast this morning. High pressure will then build south of the area through Sunday. The next cold front will approach the area Monday.

7 Day Forecast for Marine Location Near Mantua, VA
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location: 38.84, -77.25     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 180844
afdlwx
area forecast discussion
national weather service baltimore md washington dc
344 am est Thu jan 18 2018

Synopsis
Low pressure off the carolina coast will push out to sea today.

High pressure will build south of the area through the weekend.

A cold front will cross the area early next week.

Near term through tonight
Surface low pressure is intensifying off the nc coast this
morning as an upper level low moves along the nc va border. As
the upper low is departing to the east, mid level clouds have
been dissipating. Over much of the area, temperatures in the
teens with a 5-15 mph wind are resulting in wind chills in the
single digits. High elevation stations indicate wind chills less
than -10, where a wind chill advisory continues until 9 am.

For today, the gradient between the departing low and high
pressure over the deep south will result in continued breezy
conditions with 20-25 mph gusts at times. A wind speed max
resides in a subsidence inversion a few thousand feet above sea
level. Am thinking the inversion results in poor mixing
(reference pie 2g4 forecast soundings), negating the need for a
high elevation wind advisory, though can't rule out criteria
being met on the highest exposed peaks. Otherwise, subsidence
behind the departing trough should result in mainly clear skies.

Warm advection aloft and downsloping flow will result in highs
making it above freezing for the lower elevations, and into the
40s south of i-66 in va.

Tonight, the gradient will relax a little, which should allow
our typical colder valleys to decouple. A weak shortwave trough
could bring some cirrus but otherwise skies will be mostly
clear. Have gone near or lower than colder guidance in these
locations, with dew points supporting lows in the mid teens.

Lower to mid 20s can be expected in the cities and locations
which maintain a light breeze.

Short term Friday through Saturday night
High pressure will slide by to our south Friday and Saturday.

Some cirrus from the northern stream jet may pass by at times,
but that's about it weather-wise. The main story will be
temperatures which will continue to warm. The only limiting
factor will be how much mixing can occur under a strong
subsidence inversion. High temperatures in the 50s will be
limited south of i-66 on Friday, but will encompass more of the
area by Saturday. Overnight lows will be in the mid 20s to lower
30s Friday night and lower to mid 30s Saturday night.

By Saturday night, isentropic ascent increases west of the
appalachians ahead of a developing low pressure system in the
plains. Any light precipitation is expected to remain west of
the divide. Forecast soundings would likely support
drizzle light rain, so any isolated pockets of below-freezing
temperatures could pose a concern. Will limit this mention to
this discussion for now due to isolated nature low probability
combination.

Long term Sunday through Wednesday
High pressure will be located along the south carolina coast on
Sunday, with a warm front lifting northward to our west as a
low pressure system develops over the central plains. Isentropic
lift is not strong and frontogenesis is weak, but there may be
just enough moisture in the return flow combined with the meager
forcing to cause some light rain or drizzle along and west of
the allegheny front. This could be a concern if temps hang near
freezing, especially early in the day, but this concern should
diminish later in the day as temps moderate. Further east, drier
air and less forcing should prevail to keep most of the CWA dry
on Sunday.

Southerly flow will prevail Sunday and Monday as the high
shifts east off the coast and the storm in the plains moves
northeast towards the great lakes, but enough of a weak wedge
may get stuck on the eastern side of the mountains to prevent a
strong warmup. Nevertheless, temps will be above normal for late
january, with highs likely reaching the 50s both days, with
Monday the warmest day. It is possible temps pop into the 60s on
Monday just ahead of the cold front, but uncertainty is high on
this due to the timing of the front during the overnight.

Showers don't look likely across most of the CWA until later
Monday night, with showers likely to linger early Tuesday as the
storm from the plains passes north and drags its cold front
across the area. Mild temps early may drop later in the day,
though this is dependent on timing. Rainfall doesn't look
particularly heavy and a couple days of warmer weather should
allow most soils to thaw, so not expecting a big hydro concern
with this system. We still need rain.

Dry weather returns as high pressure builds in from the west on
Wednesday, but as this high has more of a pacific origin, temps
may only drop to near normal.

Aviation 09z Thursday through Monday
Vfr conditions expected today as a low pressure system moves
offshore. However, the gradient between this system and high
pressure in the deep south will result in gusty west winds
around 20 kt. Winds will subside tonight. No further impactful
weather is expected through Saturday, with west winds gradually
backing to the southwest.

Vfr likely Sunday and Monday, though will need to watch for
possible low CIGS as warmer, moist air moves north over our
region ahead of the next cold front.

Marine
While there was a bit of a lull on some of the waters earlier,
gustiness has increased again as temperatures continue to fall
further below water temperatures and low pressure strengthens as
it moves off the carolina coast. Therefore, an SCA will be in
effect for all waters until 4 pm this afternoon. It's possible
winds subside in some areas before that as air temperatures rise
through the 30s to near 40. Westerly winds will continue
through Friday as high pressure builds south of the area,
becoming more southwesterly by Saturday. A strong subsidence
inversion and warm temperatures should keep winds below sca
thresholds.

Winds likely sub-sca Sunday and Monday as high pressure slides
east off the coast ahead of the next cold front.

Lwx watches warnings advisories
Dc... None.

Md... Wind chill advisory until 9 am est this morning for mdz501.

Va... Wind chill advisory until 9 am est this morning for vaz503-504-
507-508.

Wv... Wind chill advisory until 9 am est this morning for wvz501-503-
505-506.

Marine... Small craft advisory until 4 pm est this afternoon for
anz530>543.

Synopsis... Rcm
near term... Ads
short term... Ads
long term... Rcm
aviation... Ads rcm
marine... Ads rcm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 12 mi45 min WNW 5.1 G 9.9 20°F 33°F1023.2 hPa
NCDV2 38 mi45 min WNW 1.9 G 5.1 22°F 31°F1022.1 hPa
APAM2 - 8575512 - Annapolis, MD 42 mi45 min 20°F 1021.5 hPa
TPLM2 - Thomas Point, MD 43 mi33 min WNW 12 G 13 21°F 31°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 46 mi45 min W 9.9 G 12 20°F 1021.9 hPa
BLTM2 - 8574680 - Baltimore, MD 46 mi45 min NW 1.9 G 7 19°F 33°F1021.5 hPa
CPVM2 47 mi45 min 20°F 6°F
FSNM2 47 mi45 min W 8.9 G 13 19°F 1020.9 hPa
44062 - Gooses Reef, MD 48 mi33 min N 19 G 21 23°F 32°F2 ft1023.2 hPa (+1.8)

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA8 mi97 minNW 610.00 miFair21°F3°F47%1023.1 hPa
Washington/Reagan National Airport, DC, VA12 mi41 minNW 9 G 1810.00 miA Few Clouds22°F5°F48%1022.8 hPa
Washington/Dulles International Airport, DC, VA13 mi41 minNW 12 G 2010.00 miA Few Clouds22°F5°F48%1022.6 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA17 mi37 minNNE 310.00 miFair13°F6°F74%1024.1 hPa
College Park Airport, MD20 mi56 minWNW 510.00 miFair18°F4°F54%1022.3 hPa
Camp Springs / Andrews Air Force Base, MD20 mi37 minWNW 1210.00 miFair19°F5°F54%1022.4 hPa
Quantico Marine Corps Airfield - Turner Field, VA23 mi97 minWNW 610.00 miPartly Cloudy15°F10°F84%1023.7 hPa
Gaithersburg - Montgomery County Airport, MD23 mi37 minW 810.00 miFair16°F5°F62%1024.8 hPa
Leesburg / Godfrey, VA24 mi38 minNW 11 G 1610.00 miFair23°F10°F58%1022.7 hPa

Wind History from DAA (wind in knots)
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Last 24hrNW13
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1 day agoCalmSW3SE3SE5S6SE5S6CalmS3CalmCalmCalmCalmCalmCalmNW8NW7NW7N4NW9NW12N7N8
G16
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G19
2 days agoCalmN3NW3NW3CalmCalmCalmNE3CalmCalmCalmCalmSE4CalmSE5CalmCalmCalmCalmCalmCalmCalmCalmCalm

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Thu -- 03:57 AM EST     -0.10 feet Low Tide
Thu -- 07:24 AM EST     Sunrise
Thu -- 08:19 AM EST     Moonrise
Thu -- 09:29 AM EST     2.43 feet High Tide
Thu -- 03:51 PM EST     -0.10 feet Low Tide
Thu -- 05:13 PM EST     Sunset
Thu -- 06:52 PM EST     Moonset
Thu -- 09:36 PM EST     2.69 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.50.90.40.1-0.10.10.81.62.12.42.421.40.80.30-0.10.10.81.62.32.62.72.4

Tide / Current Tables for Chain Bridge, Washington, D.C.
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Chain Bridge
Click for Map
Thu -- 03:57 AM EST     -0.15 feet Low Tide
Thu -- 07:24 AM EST     Sunrise
Thu -- 08:19 AM EST     Moonrise
Thu -- 09:32 AM EST     2.46 feet High Tide
Thu -- 03:52 PM EST     -0.15 feet Low Tide
Thu -- 05:13 PM EST     Sunset
Thu -- 06:52 PM EST     Moonset
Thu -- 09:38 PM EST     2.72 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.50.90.40-0.20.10.81.52.12.42.421.50.80.3-0-0.10.10.71.62.32.72.72.4

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 (8,2,3,4)
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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.