Friday, March22, 2019 L-36.com


Marine Weather and Tides
National Harbor, 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 7:07AMSunset 7:23PM Friday March 22, 2019 10:00 AM EDT (14:00 UTC) Moonrise 8:26PMMoonset 7:24AM Illumination 97% 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- 737 Am Edt Fri Mar 22 2019
.gale warning in effect through late tonight...
Today..W winds 20 to 25 kt with gusts to 35 kt. Waves 2 ft. Numerous showers with isolated tstms this afternoon.
Tonight..NW winds 15 to 20 kt with gusts to 35 kt. Waves 2 ft.
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 5 kt. Waves less than 1 ft.
Sun night..SW winds around 5 kt. Waves 1 ft.
Mon..W winds around 5 kt...becoming n. Waves 1 ft. Showers likely
Tue...ne winds 5 to 10 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 737 Am Edt Fri Mar 22 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will strengthen as it moves toward the canadian maritimes through tonight. High pressure will return for the weekend before low pressure and its associated cold front impact the waters early next week. The gale warning may be need to be continued into Saturday morning, but otherwise a small craft advisory will likely be needed Saturday into Saturday night. Small craft advisories may also be needed Monday into Tuesday.


7 Day Forecast for Marine Location Near National Harbor, MD
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location: 38.8, -77.03     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 221040 aaa
afdlwx
area forecast discussion... Updated
national weather service baltimore md washington dc
640 am edt Fri mar 22 2019

Synopsis
Low pressure will intensify as it moves toward the canadian
maritimes through tonight. High pressure will return for the
weekend. The next low pressure system will pass near the area on
Monday, then canadian high pressure will build in for the
middle of next week.

Near term through tonight
The headline for the day will focus on potential for strong wind
gusts, though the set-up is somewhat complicated.

Deepening low pressure is approaching long island early this
morning, with its associated rainfall exiting northeast maryland
by 8 am or so. Gusty winds will continue since the pressure
gradient will remain tight, but there might be a relative lull
during the morning hours. The Sun will likely make an appearance
at times, with temperatures pushing into the upper 40s and 50s.

During the afternoon and evening, a shortwave trough and
associated strong vort MAX and surface cold front will dive into
the area. This feature will have good lift, and low and mid
level lapse rates will be steep. A few hundred j kg of
instability seem likely, which will result in some low top
convection developing. Upped pops to likely across much of the
area since coverage looks decent per cams, though rain at any
one location will likely be fairly brief. Given the low freezing
levels and steep lapse rates, some small hail and gusty winds
will be possible. Have included isolated thunder in the
forecasts, though lightning strikes may be few and far between.

This activity will exit, but a pressure surge and cold advection
behind the front will result in strong gradient winds continuing
through the evening. There is some uncertainty on how efficient
mixing will be, but 40 kt winds will be located about 1500 ft
off the surface.

For the moment, have issued a wind advisory for areas where
there is higher confidence of strong wind gusts: the higher
elevations and adjacent portions of the far northwest
baltimore washington suburbs. Winds during the afternoon might
be more sporadic and tied to convection, while evening winds may
be sporadic due to mixing issues... But the threat for 45+ mph
gusts seems likely. Have areas east of the blue ridge ending at
midnight, and 4 am in higher elevations... When stability is
expected to start increasing. Will allow day shift to determine
if the threat extends farther east.

The other story will be upslope snow showers and squalls... Which
could be intense at times above 3000 ft or so. Will continue the
winter weather advisory for the period of most intense snows,
although some scattered snow showers may persist well into
tonight.

Skies clear east of the allegheny front tonight with lows
dropping into the mid 20s to lower 30s.

Short term Saturday through Sunday night
Breezy conditions will continue Saturday as the trough axis
exits, but gusts should remain in the 25-40 mph range. Surface
high builds overhead Saturday night and then pushes to the east
Sunday. Seasonably cool temperatures Saturday will rebound back
to near or above normal Sunday as return flow begins.

Shortwave trough and surface low will be moving into the ohio
valley Sunday night. Some light showers may move into the area
ahead of this feature. Temperatures are expected to remain
above freezing.

Long term Monday through Thursday
A surface front will push southeastward towards the area early
Monday, likely crossing the area during the day. As it does so, a
wave of low pressure will be moving along the front. Thus, a period
of rain is expected on Monday. Temperatures will initially be mild
ahead of the front, although highs will be determined by timing of
the frontal passage. Will show a blended solution of 50s to around
60f for now. Temperatures will fall post-frontal, and it remains
possible that the rain will end as some snowflakes, especially
across the higher terrain.

Much cooler air will follow behind the front for the Monday night
through Wednesday night time period as strong high pressure builds
across the region. Temperatures likely average about 10 degrees or
so below normal, with clear skies and radiational cooling at night
and sunshine during the day. Lows likely to be in the 20s 30s with
highs in the 40s to low 50s. The coolest day will be Tuesday with
the coldest night likely Tuesday night.

Dry weather will continue into Thursday, but with milder conditions
expected on developing southerly flow as the high slides to the
coastline. Highs Thursday likely get back to near 60f.

Aviation 12z Friday through Tuesday
Low pressure and its associated rain are moving away from the
area early this morning. Can't rule out some intermittent MVFR
conditions through sunrise. Winds are also gusting around 25 kt,
although they may have a temporary lull later this morning.

Potent trough axis will cross the area this afternoon, with
brief showers convection looking likely at (or near) most
terminals between 18-21z. These showers could contain strong
wind gusts and small hail, though they may not be heavy enough
to reduce ceilings visibility. While winds will be gusty all
day, the strongest surge is expected to arrive during the late
afternoon and early evening with gusts 35-40 kt possible.

High pressure will be building from the west tonight and will
remain in control through Saturday. 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.VFR
continues through Sunday, though some showers may approach ahead
of the next system late Sunday night.

Potential for sub-vfr conditions exists Monday in rain as a frontal
system crosses the region.VFR returns for Tuesday.

Marine
Low pressure continues to lift northeastward away from the area and
intensify. NW flow on the backside of low pressure has been resulting
resulting in at least intermittent gale force gusts overnight.

Gale warning now in effect from tonight through 6 am Saturday,
though such gusts may not be continuous. A reinforcing trough
axis will provide a better, deeply mixed environment, with the
strongest gusts expected generally during the evening hours
today. Scattered to numerous showers may also contain locally gusty
winds over gale force this afternoon. The gale warning may need
to be extended into early Saturday morning, but otherwise small
craft advisories will likely be needed through the day.

On Sunday, winds will be 10 to 15 knots out of the south as high
pressure moves offshore.

Sca conditions likely on southwest winds Monday ahead of an
approaching frontal system, and then likely again on northerly winds
Monday night and Tuesday behind the frontal passage.

Hydrology
With widespread rainfall ending early this morning, the faster
responding streams creeks are receding, however the mainstem rivers
continue to rise and flood warnings continue along the potomac,
rappahannock, monocacy, and opequon rivers, as well as the goose,
conococheague, and seneca creeks. Flooding also remains
possible along the shenandoah river at millville. Please see
individual flood warnings for additional information.

Tides coastal flooding
Water anomalies should drop off considerably at most sites through
today with strong northwest winds. The exceptions will be along the
potomac at washington alexandria, especially at georgetown as
freshwater is transported downstream. Coastal flood advisories
are in effect for the next high tide cycle and additional
cycles will likely need to be added for georgetown, with
moderate flooding and therefore coastal flood warnings a
possibility.

Lwx watches warnings advisories
Dc... Coastal flood advisory until 1 pm edt this afternoon for
dcz001.

Md... Wind advisory from noon today to 4 am edt Saturday for mdz003-
501-502.

Wind advisory from 2 pm this afternoon to midnight edt tonight
for mdz004-005-503-505.

Va... Wind advisory from noon today to 4 am edt Saturday for
vaz025>031-503-504-507-508.

Winter weather advisory until 9 pm edt this evening for vaz503.

Wind advisory from 2 pm this afternoon to midnight edt tonight
for vaz501-505-506.

Coastal flood advisory until noon edt today for vaz054.

Wv... Wind advisory from noon today to 4 am edt Saturday for
wvz050>053-055-501>506.

Winter weather advisory until 9 pm edt this evening for wvz501-
503-505.

Marine... Gale warning until 6 am edt Saturday for anz530>543.

Synopsis... Ads
near term... Ads
short term... Ads
long term... Mm
aviation... Ads mm
marine... Ads mm
hydrology... Mm
tides coastal flooding... Mm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 5 mi42 min 1004 hPa
BSLM2 - Chesapeake Bay, MD 17 mi150 min NW 9.9 46°F 1002 hPa36°F
APAM2 - 8575512 - Annapolis, MD 32 mi42 min 46°F 1001.7 hPa
TPLM2 - Thomas Point, MD 32 mi60 min W 24 G 27 46°F 45°F1002.6 hPa (+2.4)33°F
NCDV2 33 mi48 min 47°F 1003.6 hPa
CPVM2 37 mi42 min 47°F 33°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 39 mi42 min 45°F 1001.3 hPa
FSNM2 39 mi48 min 1001.3 hPa
BLTM2 - 8574680 - Baltimore, MD 40 mi42 min 1001.7 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 44 mi42 min 47°F 1003.1 hPa
SLIM2 - 8577330 - Solomons Island, MD 45 mi42 min 48°F 46°F1002.4 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA4 mi68 minNW 22 G 3210.00 miPartly Cloudy and Breezy47°F30°F52%1003.3 hPa
Camp Springs / Andrews Air Force Base, MD9 mi2.1 hrsWNW 19 G 2710.00 miPartly Cloudy and Breezy45°F32°F63%1002.5 hPa
Fort Belvoir, VA9 mi2.1 hrsWNW 17 G 2610.00 miOvercast46°F33°F63%1003.4 hPa
College Park Airport, MD14 mi76 minWNW 10 G 1610.00 miMostly Cloudy44°F32°F63%1002.7 hPa
Fort Meade / Tipton, MD24 mi78 minWNW 15 G 2310.00 miPartly Cloudy43°F33°F71%1003 hPa

Wind History from DCA (wind in knots)
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Last 24hrN8N8N12NE12NE11N12NW13NW15
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1 day agoCalmS4S7SW66S5SE4SE9SE10SE8E6E6SE8SE7E8E4CalmNE7N7NE10N8NE7N9N7
2 days agoNE6CalmSE3SE6W6CalmNE6N6N8N6E8SE8S5SE3S4SW3S7S4CalmCalmCalmCalmCalmE3

Tide / Current Tables for Alexandria, Virginia
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Alexandria
Click for Map
Fri -- 04:16 AM EDT     -0.23 feet Low Tide
Fri -- 07:08 AM EDT     Sunrise
Fri -- 08:23 AM EDT     Moonset
Fri -- 09:58 AM EDT     3.49 feet High Tide
Fri -- 04:48 PM EDT     -0.33 feet Low Tide
Fri -- 07:21 PM EDT     Sunset
Fri -- 09:26 PM EDT     Moonrise
Fri -- 10:28 PM EDT     3.27 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.11.40.70.2-0.2-0.10.61.72.73.33.53.22.51.810.4-0.1-0.30.1122.83.23.2

Tide / Current Tables for Riverview, 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 (10,2,3,4)
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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.