Thursday, January17, 2019 L-36.com


Marine Weather and Tides
Indian Head, MD

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 7:22AMSunset 5:15PM Thursday January 17, 2019 4:18 AM EST (09:18 UTC) Moonrise 1:58PMMoonset 3:31AM Illumination 86% Phase: Waxing Gibbous; Moon at 11 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- 336 Am Est Thu Jan 17 2019
Rest of the overnight..N winds 5 kt. Waves less than 1 ft.
Today..E winds 5 kt. Waves less than 1 ft. A chance of snow. Vsby 1 to 3 nm.
Tonight..S winds 5 kt. Waves less than 1 ft. Periods of snow. Vsby 1 to 3 nm.
Fri..W winds 5 kt. Waves less than 1 ft.
Fri night..N winds around 5 kt. Waves 1 ft.
Sat..E winds 5 to 10 kt. Waves 1 ft. Rain or a chance of snow.
Sat night..SE winds 5 to 10 kt. Waves 1 ft. Rain.
Sun..NW winds 10 to 15 kt. Waves 1 ft. Rain or snow and sleet likely in the morning, then a chance of snow in the afternoon.
Mon..NW winds 10 to 15 kt...diminishing to 5 kt after midnight. Waves 1 ft.
ANZ500 336 Am Est Thu Jan 17 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will build overhead through this morning. Low pressure will track through the great lakes later today and tonight, and the cold front associated with this low will pass through the waters Friday. Another low pressure system will affect the area over the weekend. Small craft advisories may be needed for portions of the waters Saturday and a gale warning may be needed Sunday and Monday.


7 Day Forecast for Marine Location Near Indian Head, MD
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location: 38.62, -77.2     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 170855
afdlwx
area forecast discussion
national weather service baltimore md washington dc
355 am est Thu jan 17 2019

Synopsis
High pressure will move offshore today and low pressure will
pass by to our west tonight. The cold front associated with the
low will move through the area Friday before high pressure
briefly builds overhead Friday night into early Saturday.

Stronger low pressure will track through the tennessee valley
Saturday, before passing through our area Saturday night into
Sunday. Arctic high pressure will build overhead later Sunday
through Monday before moving offshore Tuesday.

Near term through tonight
High pressure extends into the area from southern canada this
morning while the next low pressure system is poised in oklahoma.

Between moisture trapped under a subsidence inversion and advancing
clouds ahead of the low pressure system, skies are mostly cloudy to
cloudy, and it's doubtful much Sun will be seen today. Temperatures
won't rise much as a result, remaining in the 30s for most locations.

The low center will track up the ohio valley this afternoon and into
the lower great lakes tonight. Increasing isentropic ascent may lead
to some light snow over western areas during the midday hours, but
the bulk of the precipitation will fall during the late afternoon
and evening. There is still a bit of spread amongst model guidance
in terms of onset time, and thus uncertainty on if the evening rush
hour in the metro areas will be impacted. At the moment, higher
confidence lies in the western suburbs, where surface temperatures
will also be colder. Have therefore issued a winter weather advisory
for this area. Have also included portions of north central maryland
and the far eastern panhandle of west virginia, where there is some
guidance agreement on an area of 2 inch totals. Amounts generally
around an inch or less will be found across much of the CWA in this
modest QPF event. Higher totals will be found along the allegheny
front from a combination of synoptic and upslope snow, so a winter
weather advisory is also in effect for this area. Future adjustments
to the advisories may be needed.

After dropping with sunset, temperatures in most areas will either
hold steady or rise a few degrees through the night as low level
flow becomes southeasterly. For the most part, the column will rise
above freezing from warm air advection aloft nearly coincident with
where surface temperatures will be above freezing. So while some
sleet pellets or drizzle freezing drizzle could occur as
precipitation tapers off, it will largely be a snow (with some rain
in the southeast) event. All precipitation east of the allegheny
front will likely have ended by daybreak.

Short term Friday through Friday night
The associated cold front will pass early Friday. In most areas,
this should lead to at least partial clearing and warmer
temperatures in the 40s to near 50. However, due to a weak gradient,
there are some indications that there might not be enough flow to
scour out low level moisture across north central maryland, which
would lead to cloudier and cooler conditions. Upslope snow showers
will continue through midday along the allegheny front with
additional minor accumulations. High pressure will extend into the
area Friday night with lows in the 20s to around 30.

Long term Saturday through Wednesday
Arctic high pressure well to our north will wedge down into the
mid-atlantic Saturday while low pressure intensifies as it moves
through the plains and into the tennessee valley. The low will
be in the southern stream of a split jet, which means that deep
moisture will get wrapped into this system. The low is most
likely track toward the appalachians Saturday night before
passing through our area late Saturday night into Sunday. The
low will move well off to our north and east later Sunday and
arctic high pressure will build overhead Sunday night through
Monday.

For Saturday through midday Sunday... The latest 00z guidance
continues to suggest that the low will track closer to the
appalachians as opposed to our south or along the coast. This
would put our area on the "warmer" side of the storm, which
means that there is a better chance for rain or a wintry mix
changing to rain for most areas instead of significant snow. The
00z ensemble fields also show this being the most likely
scenario. This scenario continues to make sense given the the
synoptic signals such as the subtropical ridge poking into the
southeastern CONUS ahead of this system, and the higher
pressures from the arctic high being over the plains instead of
new england ahead of the storm.

As of now, it appears that the most likely scenario for
Saturday into Sunday is for precipitation to develop later
Saturday morning and afternoon due to warm and moist air
overrunning the relatively colder air. A potent southerly low-
level jet will develop Saturday night while shortwave energy
passes through in association with the approaching low. This is
when the steadiest precipitation is expected. A soaking rain and
wintry mix are expected during this time. See next paragraph
for details on p-type. Bitterly cold but drier air will
gradually return Sunday as the low move off to the north and
east. Timing is a little uncertain as of now, but it does look
like steady precipitation should end across most areas by
midday.

As for p-type, going with the most likely scenario which tracks
the low close to the appalachians before developing into a
coastal low and moving well off to our north and east, this will
allow for plenty of warm air to overspread the area from south
to north. However, arctic high pressure will be entrenched to
our north so there will be low-level cold air in place.

Therefore, a wintry mix is most likely at the onset for most
locations. However, the warmer air should quickly take over for
locations near and east of the interstate 95 corridor limiting
any wintry precipitation. Farther north and west, cold air will
be deeper to start, and trapped in the valleys for much of the
event. Therefore, more significant snow and or ice is possible.

One thing to note is the ridge axis that extends down from the
high seems to poke down into the shenandoah valley, and low-
level colder air is usually tough to displace north and west of
this ridge axis. Did lean closer to the colder guidance
regarding low-level temperatures for this reason. Therefore, it
appears that the most likely chance for significant snow and or
ice would be near and west of interstate 81 to the allegheny
highlands. The latest forecast does indicate this, but
admittedly confidence is low because there is still some model
divergence on the exact track of the low.

Another thing to note is that the arctic high is quite strong
even to our north as well as our northwest. Therefore, a slight
southward track in the low cannot be ruled out at this time, and
if that does occur then more significant wintry precipitation
could make it closer to the i-95 corridor. There are still a few
ensemble members showing that this is a possibility, but again
the large majority of them point to the previous situation with
the low being a bit farther north.

For later Sunday and Monday: the low will move away from the
area later Sunday, and an arctic cold front associated with the
low will pass through the area. Windy and bitterly cold
conditions are expected behind the cold front for later Sunday
and Sunday night. The precipitation may even end as a brief
period of snow wintry mix. The rapid drop in temperatures also
means that any wet surfaces or standing water will rapidly
freeze. Gusty northwest winds and bitterly cold air will
continue Sunday night into Monday ahead of arctic high pressure.

Wind chills below zero are possible Sunday night into Monday,
and wind chills are likely to be well below zero in the
mountains during this time. Another possible hazard Sunday night
into Monday may be localized snow showers. Do think coverage
would be very limited, but given the cold air in place and
strong cold advection, a streamer or two may make it east of the
mountains.

Arctic high pressure will build overhead Monday night and
bitterly cold conditions will persist, but winds will diminish.

The high will move offshore Tuesday and Wednesday, allowing for
a moderating trend.

Aviation 08z Thursday through Monday
Despite high pressure over the region this morning, ceilings around
4-5kft are trapped under a subsidence inversion and will likely
linger through the morning. Ceilings will lower as a low pressure
system approaches from the west this afternoon. Periods of light
snow will begin from west to east this afternoon early evening, with
the steadiest snow expected during the evening hours before tapering
off late tonight. Visibility and ceiling restrictions will likely
fall to MVFR and could be ifr at times. As the cold front clears the
area on Friday, conditions should gradually improve. However, flow
will be weak behind the front, so low level moisture may have
difficulty scouring out, especially over the baltimore terminals.

OtherwiseVFR conditions and light winds are expected through Friday
night as weak high pressure build into the area.

Low pressure will track toward the appalachians Saturday before
passing through our area Saturday night into Sunday. Warm and
moist air will overrun cold air in place, causing a wintry mix
Saturday that will change to rain for most areas. The wintry mix
will be most prolonged at kmrb. Ifr conditions are likely to
develop later Saturday. Widespread rain is expected Saturday
night, but a wintry mix will likely hold on around kmrb. Ifr and
subifr conditions are expected.

Cigs vsbys will improve Sunday as the low moves away from the
area, but gusty northwest winds and bitterly cold conditions
are expected. The gusty winds will hang around through Monday
before diminishing Monday night.

Marine
Low pressure will approach the waters Saturday before passing
through early Sunday and then moving well off to the northeast
late Sunday. High pressure will build over the waters early
next week. A small craft advisory will likely be needed for the
waters later Saturday and Saturday night. A gale warning will
likely be needed Sunday and possibly into Monday.

Light west to northwest winds are expected this morning with high
pressure to the north. Winds will eventually become easterly and
southeasterly late today and tonight as low pressure passes to the
northwest, but will remain below SCA criteria. Snow and rain are
possible over the waters, especially this evening. The associated
cold front will cross the waters early Friday, but the flow behind
it is weak, so no advisories are expected through Friday night as
weak high pressure builds in.

Tides coastal flooding
An onshore flow will increase later Friday through Saturday
night as low pressure passes through the area. Minor tidal
flooding for sensitive areas near high tide is possible during
this time. A strong offshore flow will develop later Sunday and
Monday. Tidal blowout conditions are possible during this time.

Lwx watches warnings advisories
Dc... None.

Md... Winter weather advisory from 3 pm this afternoon to 6 am est
Friday for mdz501.

Winter weather advisory from 4 pm this afternoon to 4 am est
Friday for mdz003-004-503.

Winter weather advisory from 6 pm this evening to 4 am est
Friday for mdz005-006-505-507.

Va... Winter weather advisory from 3 pm this afternoon to 6 am est
Friday for vaz503.

Winter weather advisory from 4 pm this afternoon to 4 am est
Friday for vaz505-506.

Wv... Winter weather advisory from 3 pm this afternoon to 6 am est
Friday for wvz501-503-505.

Winter weather advisory from 4 pm this afternoon to 4 am est
Friday for wvz051>053.

Marine... None.

Synopsis... Bjl
near term... Ads
short term... Ads
long term... Bjl
aviation... Bjl ads
marine... Bjl ads
tides coastal flooding... Bjl


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 20 mi30 min NW 2.9 G 5.1 37°F 38°F1027.3 hPa
NCDV2 22 mi42 min Calm G 1.9 31°F 40°F1026.4 hPa
BSLM2 - Chesapeake Bay, MD 28 mi108 min N 1 33°F 1027 hPa28°F
SLIM2 - 8577330 - Solomons Island, MD 45 mi30 min NNE 1 G 1.9 35°F 41°F1026.4 hPa
TPLM2 - Thomas Point, MD 45 mi78 min WSW 8 G 8.9 37°F 38°F1027.6 hPa (+0.4)25°F
APAM2 - 8575512 - Annapolis, MD 46 mi30 min 36°F 1026.1 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 46 mi36 min NNW 5.1 G 8 37°F 1027.2 hPa
PPTM2 - 8578240 - Piney Point, MD 49 mi36 min NNE 1.9 G 1.9

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA8 mi22 minN 010.00 miFair29°F24°F82%1027.5 hPa
Quantico Marine Corps Airfield - Turner Field, VA9 mi22 minWNW 510.00 miFair28°F26°F92%1027.7 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA18 mi22 minN 010.00 miA Few Clouds24°F21°F88%1028.1 hPa
Washington/Reagan National Airport, DC, VA19 mi26 minWNW 610.00 miOvercast39°F23°F53%1027.2 hPa
Stafford, Stafford Regional Airport, VA20 mi23 minN 010.00 miFair26°F26°F100%1028.4 hPa
Camp Springs / Andrews Air Force Base, MD23 mi22 minN 010.00 miFair35°F22°F61%1027.3 hPa

Wind History from DAA (wind in knots)
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Last 24hrCalmCalmCalmCalmCalmCalmCalmNW7NW11NW9W6NW10NW5NW7NW5NW7NW9NW4N3N5N3NW3CalmCalm
1 day agoCalmCalmCalmCalmCalmNW7NW12NW9NW6NW10N5NW7NW4CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalm
2 days agoNW4NW4NW4CalmNW5N3N4N4N3NW6NW4W3W3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalm

Tide / Current Tables for High Point, Occoquan Bay, Virginia
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High Point
Click for Map
Thu -- 03:10 AM EST     1.30 feet High Tide
Thu -- 03:30 AM EST     Moonset
Thu -- 07:24 AM EST     Sunrise
Thu -- 09:13 AM EST     -0.06 feet Low Tide
Thu -- 01:58 PM EST     Moonrise
Thu -- 03:24 PM EST     1.57 feet High Tide
Thu -- 05:13 PM EST     Sunset
Thu -- 10:32 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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0.611.21.31.210.60.30-0.1-00.20.611.41.61.51.310.60.30.1-0-0

Tide / Current Tables for Marshall Hall, Potomac River, Maryland
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


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 (4,6,7,8)
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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.