Friday, March22, 2019 L-36.com


Marine Weather and Tides
Washington, DC

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 7:22PM Friday March 22, 2019 8:32 PM EDT (00:32 UTC) Moonrise 8:26PMMoonset 7:24AM Illumination 96% Phase: Waning Gibbous; Moon at 17 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- 738 Pm Edt Fri Mar 22 2019
.gale warning in effect until 6 am edt Saturday...
.small craft advisory in effect from 6 am edt Saturday through Saturday afternoon...
Tonight..NW winds 15 to 20 kt with gusts to 35 kt. Waves 2 ft. Scattered showers this evening.
Sat..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Sat night..NW winds 10 to 15 kt with gusts to 20 kt...diminishing to around 5 kt after midnight. Waves 1 ft.
Sun..SW winds around 5 kt. Waves 1 ft.
Sun night..SW winds around 5 kt. Waves 1 ft.
Mon..NW winds around 5 kt. Waves 1 ft. Rain likely.
Mon night..N winds 5 to 10 kt. Waves 1 ft. A chance of rain.
Tue..NE winds 5 to 10 kt. Waves 1 ft. A chance of rain in the morning.
Wed..SE winds around 5 kt. Waves 1 ft.
ANZ500 738 Pm 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 Washington, DC
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location: 38.89, -77.03     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 221904
afdlwx
area forecast discussion
national weather service baltimore md washington dc
304 pm edt Fri mar 22 2019

Synopsis
An upper level disturbance will pass east of the area this
evening. 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
Vigorous shortwave entering the potomac highlands at this time.

Traffic cams show snowfall near frostburg, but accumulations
challenged by Sun angle. Believe it will be the strong shortwave
induced lift and high inversion heights responsible for mountain
snow. Froude numbers peak late this afternoon, and then decline
as inversion heights lower. Latest model soundings suggest snow
totals may be on the high end of forecast, but do not have
confidence in warning numbers.

As the shortwave tracks east, which will occur through 00z, it
will be responsible for a brief period of deep lift. If full
mixing were realized, the top of the mixed layer would be near
500 mb. Although do not believe that will occur, mixing
potential should be greater than mean layer... Which certainly
suggests that 40-50 kt gusts possible. Wind advisories ongoing,
and will remain in place. Believe that the terrain stands the
best chance at more prolonged winds, which was the rationale
behind the current configuration. The other consideration was
the positioning of strong cold advection, which should be near
the maryland pennsylvania border. Aside from that, the window
of opportunity may be rather narrow... Along and immediately
behind the trough axis.

Previous convective analysis still holds. Given the low freezing
levels and steep lapse rates, some small hail and gusty winds
will be possible. Isolated thunder remains in the forecasts due
to vertical motions.

Once the shortwave passes, subsidence will result in clearing
skies east of the mountains. Cooling will be more advective vs
radiative, which means there will be little city suburb spread.

Consensus low temperature forecasts support the current
prediction... 20s in the mountains, lower 30s along i-95.

Short term Saturday through Sunday
High pressure will build into the region through Sunday behind the
exiting shortwave on Saturday. Winds will remain elevated on
Saturday but should remain below wind advisory and gale warning
criteria as the upper level forcing shifts out of our area. I kept
winds elevated to gale warning levels until about 12z Saturday
morning as forcing will still be in place. Gust are expected to
continue above 20 knots through early Saturday afternoon but we
expect winds to start to diminish by Saturday evening. Skies will
remain mostly clear through Sunday afternoon. Clear skies along with
very light winds will allow for some decoupling to occur Saturday
evening into Sunday morning. These conditions along with low
dewpoint temperatures in the upper teens to low 20s lead me to drop
Saturday overnight temperatures down a few degrees to account for
possible radiational cooling.

A warming trend is expected through Sunday as winds become southerly
and warm air is advected into our region. Clouds will build back
into our region on Sunday as a few bits of shortwave energy moves
into our area Sunday afternoon.

Long term Sunday night through Friday
On Sunday night, an upper-level shortwave will be moving out of the
central plains and into the ohio valley. The surface low associated
with this upper-level feature will follow a similar path. The
attendant warm front could spark some shower activity over the
region Sunday night into early Monday morning. Temperatures will
stay above freezing during this period, so should remain all rain.

A larger area of low pressure in the upper levels will be centered
over quebec, this will push the aforementioned shortwave energy
south, thus pushing the surface low track south along with it. This
would essentially bring the surface low over central va.

Precipitation should be all rain throughout the day on Monday, as
high temperatures are expected to be about average, with highs in
the mid 50s to low 60s. However, there will be a push of cold air on
the back end of the surface low, so it is possible that northern
portions of the CWA see some snow mix in with rain, or perhaps even
all snow at higher elevations, as 850mb temps will be slightly below
freezing. At this point, not seeing much in the way of
accumulations. The 00z eps probabilities are only in the 10-20%
range for 1"+ of snow across the area and GEFS mean snow totals are
less than an inch for this timeframe, so will keep slight chance of
rain snow showers in the forecast for now in the climatologically
favored northern areas.

A dry, but chilly, air mass originating from canada will move into
the region behind this system on Tuesday. High temperatures will
only reach the mid to upper 40s across the region. This area of high
pressure quickly moves offshore into Wednesday, resulting in a
warming trend through the end of the week.

Aviation 18z Friday through Wednesday
An upper level disturbance will cross the terminals late this
afternoon, resulting in a brief period of potential rain.

Isolated small hail thunder possible, but confidence areal
coverage too low to justify a TAF mention. Threat covered byVFR
shower; would not rule out limited flight restrictions.

Otherwise, the concern would be the gusty winds behind the
wave... Again which could briefly spike along with trough axis
passage.

High pressure will build into the region Saturday.VFR
conditions are expected as skies becoming mostly clear through
Sunday afternoon. Winds will remain elevated out of the
northwest through Saturday afternoon with gusts over 20 knots
likely. We expect winds to diminish below 20 knots by the early
evening periods on Saturday. Higher clouds are expected build
back into our region late morning to early afternoon on
Sunday.Winds will become south to southwesterly Sunday morning.

Vfr conditions are expected through early Sunday evening.

Clouds will be on the increase Sunday night into Monday, with
showers becoming possible ahead of an approaching area of low
pressure moving out of the ohio valley. This could lead to some
visibility restrictions, especially at mrb. Rain showers are likely
through Monday afternoon for all terminals, with visibility and
ceiling restrictions likely during this timeframe as well. Rain snow
showers are possible for mrb and bwi on Monday evening as the system
pushes through the area.

Vfr conditions return by Tuesday morning and continue throughout the
rest of the week.

Marine
Winds have diminished a pinch over the course of the day.

However, a trough axis will reach the waters by 00z (8pm).

Strong wind gusts possible along with the axis, and could remain
gusty thereafter. Gale warnings in effect tonight to cover.

There is a small window of 50 gusts, so will still need to
monitor for a convective threat this evening.

High pressure will build into our region on Saturday with strong
northwesterly winds. Winds should remain well into small craft
advisory levels through Saturday afternoon. Winds are expected
to diminish below advisory levels by Saturday evening and no
small craft advisories are expected for Sunday at this time as
winds remain light out of the southwest.

Sca conditions likely due to southwesterly winds ahead of an
approaching area of low pressure on Monday. SCA conditions likely
again and on Monday night into Tuesday with northerly winds behind
the frontal passage.

Hydrology
Yesterday's rain working tis way through the waterways. Creeks
and streams receding; those flood warnings will be dropped as
appropriate per gauge readings. Still have a few mainstream rivers
rising. Please see individual flood warnings for additional
information.

Tides coastal flooding
Water levels mostly at or below astronomical normals. However,
will be monitoring assessing the impact of freshwater on
washington dc, especially georgetown.

Lwx watches warnings advisories
Dc... None.

Md... Wind advisory until 4 am edt Saturday for mdz003-501-502.

Wind advisory until midnight edt tonight for mdz004-005-503-
505.

Va... Wind advisory until 4 am edt Saturday for vaz025>031-503-504-
507-508.

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

Wind advisory until midnight edt tonight for vaz501-505-506.

Wv... Wind advisory until 4 am edt Saturday for wvz050>053-055-
501>506.

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

Marine... Small craft advisory from 6 am to 6 pm edt Saturday for
anz530>543.

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

Synopsis... Hts
near term... Hts
short term... Jmg
long term... Cjl
aviation... Hts cjl jmg
marine... Hts cjl jmg
hydrology...

tides coastal flooding...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 1 mi39 min WNW 13 G 22 45°F 49°F1007.6 hPa
BSLM2 - Chesapeake Bay, MD 19 mi123 min NW 8 46°F 1005 hPa38°F
APAM2 - 8575512 - Annapolis, MD 30 mi39 min 44°F 1005.5 hPa
TPLM2 - Thomas Point, MD 31 mi33 min WNW 23 G 25 45°F 45°F1006.7 hPa (+2.7)28°F
BLTM2 - 8574680 - Baltimore, MD 35 mi39 min NNW 13 G 22 45°F 47°F1005.5 hPa
CPVM2 35 mi39 min 45°F 27°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 35 mi39 min WNW 23 G 28 45°F 1004.9 hPa
FSNM2 35 mi81 min 45°F 1003.8 hPa
NCDV2 39 mi39 min NW 8 G 15 45°F 1007.5 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 47 mi39 min NW 25 G 32 46°F 48°F1005.3 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 48 mi39 min NNW 16 G 28 46°F 1007.1 hPa

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
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Last
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NW11
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NW10
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G25
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NW11
G24
NW13
G19
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G27
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SE3
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G5
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G6
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G9
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G21
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E3
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G7
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G6
SW2
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S1
S4
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G5
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G12
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G9
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G9

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Reagan National Airport, DC, VA2 mi41 minWNW 11 G 2510.00 miA Few Clouds45°F28°F52%1007.5 hPa
Camp Springs / Andrews Air Force Base, MD9 mi2.6 hrsNW 13 G 1810.00 miPartly Cloudy44°F37°F76%1004.5 hPa
College Park Airport, MD9 mi49 minWNW 14 G 2710.00 miFair43°F25°F50%1006.4 hPa
Fort Belvoir, VA14 mi97 minWNW 18 G 3510.00 miFair and Breezy47°F25°F43%1006.4 hPa
Fort Meade / Tipton, MD20 mi51 minWNW 11 G 2310.00 miPartly Cloudy41°F30°F66%1006.8 hPa
Gaithersburg - Montgomery County Airport, MD21 mi37 minNW 15 G 2710.00 miPartly Cloudy40°F25°F55%1010.3 hPa
Washington/Dulles International Airport, DC, VA23 mi41 minWNW 23 G 3210.00 miPartly Cloudy and Windy43°F24°F47%1008.1 hPa

Wind History from DCA (wind in knots)
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Last 24hr--NW17
G24
NW17
G26
NW16
G31
NW22
G31
NW16
G25
NW15
G26
NW15
G19
NW15
G24
NW18
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G32
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NW11
G20
NW7NW6
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W12NW15
G22
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W11
G25
1 day agoE6SE8SE7E8E4CalmNE7N7NE10N8NE7N9N7N8N8N12NE12NE11N12NW13NW15
G22
NW19
G27
NW18
G29
NW19
G27
2 days agoSE8S5SE3S4SW3S7S4CalmCalmCalmCalmCalmE3CalmS4S7SW66S5SE4SE9SE10SE8E6

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


Tide / Current Tables for Bladensburg, Anacostia 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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wmap_A
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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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Baltimore, MD/Washington (20,4,5,8)
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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.