Thursday, March21, 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 7:09AMSunset 7:22PM Thursday March 21, 2019 6:18 PM EDT (22:18 UTC) Moonrise 7:16PMMoonset 6:51AM Illumination 99% Phase: Waning Gibbous; Moon at 16 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- 439 Pm Edt Thu Mar 21 2019
.small craft advisory in effect through late tonight...
.gale warning in effect from Friday morning through Friday evening...
Rest of this afternoon..E winds 10 kt. Waves 1 ft. Rain. Vsby 1 nm or less.
Tonight..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft. Rain.
Fri..W winds 10 to 15 kt. Gusts up to 20 kt... Increasing to 35 kt in the late morning and afternoon. Waves 1 to 2 ft. A chance of showers.
Fri night..NW winds 15 to 20 kt with gusts to 40 kt. Waves 2 ft. A chance of showers.
Sat..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Sat night..NW winds 10 to 15 kt...diminishing to 5 kt after midnight. Gusts up to 20 kt. Waves 1 ft.
Sun..SW winds around 5 kt. Waves 1 ft.
Mon..N winds 5 to 10 kt. Waves 1 ft. Showers likely .
ANZ500 439 Pm Edt Thu Mar 21 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will strengthen as it moves off to the northeast tonight through Friday night. High pressure will return for the weekend before low pressure and its associated cold front impact the waters early next week. A gale warning may be needed for portions of the waters late Friday night into Saturday morning. A small craft advisory will likely be needed later Saturday into Saturday night.


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 211922
afdlwx
area forecast discussion
national weather service baltimore md washington dc
322 pm edt Thu mar 21 2019

Synopsis
Coastal low pressure will pass through the area today. The low
will intensify as it moves off to the northeast tonight through
Friday night and high pressure will return for the weekend. Low
pressure may impact the area early next week with more
unsettled conditions possible.

Near term until 6 am Friday morning
Low pressure centered over southeast virginia at this time. It
appears as though the multiple shortwaves have phased in the upper
ohio valley. With the position of these two features, the axis of
moisture has set up west of i-95 but east of the blue ridge. The
downward momentum has also transported cold air down, allowing for
snow across the ridges. As cooling continues in this column, we're
getting reports of snow below 2000 ft. However, the spring Sun angle
has kept it difficult to accumulate significantly below the mountain
tops.

We will be maintaining the winter storm warning for the blue ridge.

Not all portions of these zones will be receiving 5+ inches, but
there is enough of an impact. Similarly, accumulations of an inch or
two likely will exceed the skyline drive, but not for a substantial
enough of a swath to justify a ring of advisories surrounding the
warning.

While there is likely some brightbanding on radar, rainfall has been
significant enough to result in some flooding in the piedmont zones.

Have expanded flood watch southeast across fauquier county to meet
this identified area. As the low kicks northeast this evening, will
have an additional axis of rainfall crossing the baltimore-
washington metro region; thus the flood watch will remain in effect.

Already received an inch or two of rain in the metros, we
conceivably could double that. Guidance suggests that precipitation
will diminish before midnight. Will drop down to chance in
baltimore-washington only by 06z.

In the northwest flow that follows, upslope snow will likely develop
tonight. Inversion heights and froude numbers do appear favorable
for snowfall, however NAM and namnest output not in great agreement.

Have opted to hold off on upslope snow until the current situation
can be better captured.

Short term 6 am Friday morning through Saturday night
The shortwave trough axis will be crossing the area Friday, bringing
multiple concerns: winds across the area, accumulating upslope snow,
and scattered showers areawide. On the first two, forecast skill not
the best; advisories possible on either but would rather not make
those decisions at this time. Have higher confidence on upslope snow
than winds. Scattered showers in vicinity of the trough also highly
likely. Would not rule out graupel given modest CAPE in forecast
soundings.

Breezy conditions will continue Friday night and Saturday as trough
axis exits. However skies will clear outside of the appalachians.

Scattered snow showers should continue into at least Friday evening
until inversion heights lower.

Long term Sunday through Thursday
High pressure will slowly move out of our region on Sunday as a
upper level trough moves southward into great lakes region. Winds
will become southerly as the high pressure shifts off of the coast
late Sunday into Monday. The upper level trough will move to our
north on Monday but a shortwave associated this trough will dig down
into our region on Monday. A surface low associated with shortwave
will pass through our area on Monday along with its associated
frontal boundary. Precipitation on Monday in most areas is expected
to start off as rain and finish off with a chance for wintry mix
toward the end of the event Monday evening. There still remains a
lot of uncertainty as the exact track of the surface low will
determine how much cold air moves into our region while
precipitation is still occurring. Precipitation is expected to fully
move out of our region by the mid morning periods on Tuesday.

High pressure will build into our region on Tuesday and linger
through the later parts of next week. Winds will become northerly
behind the frontal passage and linger through Wednesday. Another
chilly air mass will build into the region next week with daytime
temperatures hovering in the 40 and overnight temperatures in the
30s.

Aviation 19z Thursday through Tuesday
Ifr conditions are observed over the main terminals this afternoon.

This is expected to continue into this evening, with periods of lifr
as a low pressure system tracks north over our area the rest of
today. Rain showers will continue this evening and conditions will
improve overnight with increasing CIGS and vsbys as the low pressure
moves away and northeast of our area.

High pressure will be building from the west late Friday and will
remain in control through Saturday.VFR conditions are expected over
the terminals Friday and Saturday. A tight pressure gradient will
cause a gradual increase in the winds on Friday, with highest gusts
expected late Friday afternoon into Friday night. Gusts of around 40
knots possible. Winds will be on the decrease on Saturday, gusting
between 25 and 35 knots in the morning and receding into the teens
by Saturday evening.

On Sunday,VFR conditions expected as high pressure slowly moves off
shore and skies remain mostly clear. Winds will be out south to
southeasterly.

Monday, a cold front will pass through the region. Rain will be
likely with subvfr conditions likely.

Marine
Mixing has been on the poor side today, but gradient increasing.

Small craft advisory in effect for most waters, expanding to all
waters tonight as mixing does improve on northwest flow. A
reinforcing trough axis will provide a better, deeply mixed
environment. Gale warnings in effect Friday and Friday evening.

Likely will need small craft advisories for a period after
that, possibly into Saturday.

On Sunday, winds will be 10 to 15 knots out of the south. At this
time small craft advisories aren't expected.

Monday, a cold front will move through the region. Winds could peak
over 18 knots especially Monday night into Tuesday. Small craft
advisories may be needed.

Hydrology
Plume of rainfall has set up between i-95 and the blue ridge,
with storm totals of 2-3 inches plausible. Flood warnings in
effect across central virginia, and flood watches north of there
through metro baltimore-washington. Rainfall will diminish this
evening, but residual runoff will persist into the night.

Based on observed and projected qpf, river level forecasts
getting mighty close to flood stage. River flood watches have
been issued for opequon at martinsburg and monocacy at
frederick, which come the closest. Will continue to monitor.

Tides coastal flooding
A persistent east to east-southeast flow into a low pressure system
riding north up the coast has allowed for water levels to rise a
little along parts of the maryland shoreline, particularly near
point lookout and adjacent shore areas of st. Marys county,
maryland. Water levels will rise about a foot to 1.5 feet above
normal. A coastal flood advisory is in effect for this area the
remainder of this afternoon into early this evening. Another area of
concern for minor coastal flooding is the washington channel and
along the shoreline of alexandria, virginia. Tidal departures will
average 1.5 to 2.0 feet above normal this evening as persistent
north-northeast winds become northwest as the low pressure system
moves by to the east. A coastal flood advisory is in effect for
these areas this evening into a few hours past midnight.

Lwx watches warnings advisories
Dc... Flood watch until midnight edt tonight for dcz001.

Coastal flood advisory until 2 am edt Friday for dcz001.

Md... Flood watch until midnight edt tonight for mdz004>006-011-013-
014-503>508.

Coastal flood advisory until 8 pm edt this evening for mdz017.

Va... Winter storm warning until 10 pm edt this evening for vaz507-
508.

Flood watch until midnight edt tonight for vaz052>054-501-502-
505-506.

Coastal flood advisory until 2 am edt Friday for vaz054.

Wv... None.

Marine... Small craft advisory until 6 am edt Friday for anz532>534-537-
540>543.

Gale warning from 6 am Friday to midnight edt Friday night for
anz530>543.

Small craft advisory until 6 am edt Friday for anz530-531-535-
536-538-539.

Synopsis... Hts
near term... Hts
short term... Hts
long term... Jmg
aviation... Imr jmg
marine... Hts jmg
hydrology... Hts
tides coastal flooding... Klw


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 20 mi37 min NW 13 G 18 45°F 50°F1003.6 hPa
NCDV2 22 mi37 min NNW 11 G 16 46°F 1001.6 hPa
BSLM2 - Chesapeake Bay, MD 28 mi109 min ENE 2.9 53°F 1003 hPa51°F
SLIM2 - 8577330 - Solomons Island, MD 45 mi31 min SE 8.9 G 12 50°F 47°F1000.3 hPa
TPLM2 - Thomas Point, MD 45 mi19 min ENE 19 G 22 52°F 45°F1001.6 hPa (-5.2)52°F
APAM2 - 8575512 - Annapolis, MD 46 mi31 min 51°F 1001.3 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 46 mi37 min SE 18 G 22 52°F 1000.7 hPa
PPTM2 - 8578240 - Piney Point, MD 49 mi31 min SE 14 G 16

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA8 mi4.4 hrsN 66.00 miLight Rain Fog/Mist47°F45°F92%1008.5 hPa
Quantico Marine Corps Airfield - Turner Field, VA9 mi83 minNNW 22 G 313.00 miRain Fog/Mist and Breezy46°F44°F93%1004.3 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA18 mi83 minNNW 13 G 212.50 miLight Rain Fog/Mist43°F42°F97%1006.7 hPa
Washington/Reagan National Airport, DC, VA19 mi27 minNW 19 G 271.25 miHeavy Rain Fog/Mist and Breezy46°F42°F86%1003.3 hPa
Stafford, Stafford Regional Airport, VA20 mi44 minNNW 17 G 2510.00 miLight Rain44°F43°F100%1004.7 hPa
Camp Springs / Andrews Air Force Base, MD23 mi4.4 hrsNE 82.00 miHeavy Rain Fog/Mist48°F47°F99%1008.5 hPa

Wind History from DAA (wind in knots)
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Last 24hrSE4SE7SE7SE5E3SE3SE3SE5E3CalmCalmCalmCalmN3N3CalmN4NW3NW4--N5--N6N5
1 day agoNW5CalmW4S3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS4SE6SE5S3SE7
2 days ago------S3S8SE4CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmN3W4S3NW7SW4W4

Tide / Current Tables for High Point, Occoquan Bay, Virginia
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High Point
Click for Map
Thu -- 02:18 AM EDT     -0.12 feet Low Tide
Thu -- 07:11 AM EDT     Sunrise
Thu -- 07:50 AM EDT     Moonset
Thu -- 08:00 AM EDT     1.94 feet High Tide
Thu -- 02:45 PM EDT     -0.18 feet Low Tide
Thu -- 07:21 PM EDT     Sunset
Thu -- 08:16 PM EDT     Moonrise
Thu -- 08:27 PM EDT     1.88 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.40.1-0.1-00.30.91.51.81.91.81.410.60.2-0.1-0.20.10.61.21.61.91.81.51.1

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 (18,4,5,8)
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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.