Sunday, September23, 2018 L-36.com


Marine Weather and Tides
Potomac Heights, MD

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9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 6:56AMSunset 7:04PM Sunday September 23, 2018 4:43 PM EDT (20:43 UTC) Moonrise 5:44PMMoonset 4:18AM Illumination 99% Phase: Waxing Gibbous; Moon at 14 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- 435 Pm Edt Sun Sep 23 2018
.small craft advisory in effect from Monday evening through late Monday night...
Rest of this afternoon..NE winds 10 kt. |* insufficient grids for waveheight during (sep 23 18 20:00:00 gmt, sep 23 18 22:00:00 gmt)*|. Drizzle or light rain likely. Patchy fog. Vsby 1 to 3 nm.
Tonight..NE winds 5 to 10 kt. Waves 1 ft. Drizzle or light rain likely. Patchy fog. Vsby 1 to 3 nm.
Mon..E winds 10 to 15 kt. Waves 1 ft. Rain likely.
Mon night..E winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft. Rain likely.
Tue..SE winds 5 to 10 kt. Waves 1 ft. A chance of rain.
Tue night..S winds 5 kt. Waves less than 1 ft.
Wed..W winds 5 kt. Waves less than 1 ft. Showers and tstms likely, then a chance of showers after midnight.
Thu..NE winds around 5 kt. Waves 1 ft or less. A chance of showers. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 435 Pm Edt Sun Sep 23 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A frontal boundary will stall south of the waters through Monday. The front will return northward as a warm front Tuesday. A cold front will then approach the waters from the ohio valley Wednesday, and may stall near or south of the waters Thursday. Small craft advisories may be needed Tuesday and Wednesday.


7 Day Forecast for Marine Location Near Potomac Heights, MD
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location: 38.62, -77.13     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 231843
afdlwx
area forecast discussion
national weather service baltimore md washington dc
243 pm edt Sun sep 23 2018

Synopsis
High pressure will build to the north over new england through
early this week. A stationary front over the carolinas will
slowly lift north as a warm front through Tuesday. A cold front
will approach from the ohio valley Wednesday, crossing the mid-
atlantic Wednesday night into Thursday before stalling.

Near term through tonight
Strengthening cool air wedge is setting up over the region with
light north to northeast flow being observed. Most of the
steadier rain has ended, with pockets of light rain, drizzle and
patchy fog remaining. This pattern will continue through tonight
with a lack of appreciable forcing or instability. Hrrr namnest
hints at convective showers or even a thunderstorm or two
approaching southern md overnight, but believe this may be a
touch overdone (northward progress of warm front and thus
instability needed for this is often very slow at night).

Temperatures won't budge much from where they are now, and in
fact may creep up a little bit overnight.

Short term Monday through Tuesday night
Isentropic lift begins to strengthen again Monday. Easterly
upslope low-level flow also increases, especially by evening.

In addition, a mid-level shortwave and right entrance region of
a 250 mb jet will pivot over the region by evening. All of this
put together should result in another period of steady rain,
with pockets of heavier rain over east facing slopes. Given the
saturated antecedent conditions, this may lead to isolated
instances of flooding, especially over the upper potomac river
basin (western md eastern wv).

Any embedded convective elements in the i-95 corridor (most
likely south of us 50) may result in isolated areas of heavier
downpours as well, but confidence in this is low given how far
south the warm front is expected to be, so even elevated
instability may be limited.

Shortwave upper jet depart to the north by Tuesday morning, but
leftover PVA tail in the wake of the shortwave and isentropic
lift ahead of the slowly advancing warm front may lead to at
least scattered pockets of rain through the day. Given the
strength of the cool air wedge in place beforehand, the ~1040 mb
high near the canadian maritimes and weak low pressure off the
carolina coast enhancing the north flow damming, i'm not
convinced the warm front gets north into pennsylvania on
Tuesday. Leaning on the slower guidance results in a
cooler cloudier forecast.

Long term Wednesday through Sunday
A cold front will approach from the west on Wednesday. Winds will be
out of the south ahead of this boundary leading to the transport of
warm and moist air into our region. GFS 12z is pointing to pw's
values near or above the two inch mark for most areas along the i-95
corridor and eastward toward the chesapeake. The storm prediction
center has placed areas west of the i-95 corridor in a 15% chance
for severe weather. The combination of high pw's along with a
approaching cold front indicates that showers will be likely on
Wednesday with thunderstorms being probable. Some thunderstorms will
have the potential to be severe and showers could produce heavy
rain. This setup would argue that flooding could be a issue
Wednesday into Thursday as the region will be already saturated from
the existing precipitation from this weekend through Tuesday. The
front is expected to pass through late Wednesday and be through our
region by Thursday morning. Showers will continue to be possible on
Thursday as the cold front that moves through is expected to stall
in southern virginia near the north carolina border. Winds will
be mainly out of the north leading to dry and cooler air being
transported into our region. Daytime temperatures look to reach
up into the mid to upper 80s on Wednesday but drop back down
into the upper 60s to low 70s on Thursday behind the frontal
passage.

Friday into Saturday, a few lingering showers will be possible early
on Friday as hints of a secondary cold front approach the
region. A high pressure system will build into our region Friday
and through the weekend. Skies will start to clear as drier and
cooler air moves into our region. Winds will continue to be out
of the north and are expected to remain light between 5 to 10
knots. Temperatures will likely be slightly below average in the
mid to upper 70s.

Aviation 18z Sunday through Friday
Ifr CIGS expected to persist well into Monday, possibly into
Tuesday with few if any breaks. Vsby will drop in ra which
looks to become steadier again by midday Monday through Monday
evening. Patchy drizzle fog possible at times as well.

Restrictions may lift a bit Tuesday as a warm front slowly tries
to lift north, but i'm not convinced it gets very far with a
strong cool air high pressure wedge in place.

Winds will generally be NE AOB 10 kts through Tuesday, gradually
shifting to the east then south by late Tuesday into Wednesday.

On Wednesday, a cold front will approach from the northwest. Winds
will begin out of the south and will become west to northwesterly
late Thursday evening. Rain will be likely with strong storms
possible. Skies will remain mostly cloudy with some cloud levels
reaching subvfr conditions.

Thursday, winds will become northerly as the cold front moves
through the region. Scattered showers may continue with mostly
cloudy skies and periods of subvfr conditions possible.

Marine
As is typical NE flow is overperforming a touch. As such, have
expanded the SCA a bit ahead of schedule. Further expansions may
be needed a bit sooner before the SCA includes all waters by
Monday evening. Winds should gradually diminish through Tuesday
as the gradient relaxes, but at least portions of the waters may
require an extension of the SCA with a more favorable direction
for channeling expected.

On Wednesday, winds will be out of the south with showers likely
along with possibly strong thunderstorms. A southerly flow will
couple with an approaching cold front to create strong winds
over the bay and lead to the need for a small craft advisory.

Thursday, scattered showers may linger over the region. Winds
will be out of the north. Small craft advisories may be needed
once again.

Hydrology
Increasing isentropic lift, PVA ahead of an approaching mid-
level shortwave, right entrance region dynamics of an upper jet
and pwats approaching 2 inches are expected to result in a
widespread steady to at times heavy rain Monday into Monday
evening. Heavy rain will be enhanced by easterly upslope flow.

Pwats may approach 2.25 inches ahead of a cold front Wednesday,
with more heavy rain seeming increasingly likely.

Given the antecedent saturated ground, this heightens the threat
for potential flooding through at least midweek.

Tides coastal flooding
Strengthening onshore flow is expected to result in renewed
coastal flooding issues as early as tonight, increasing in both
extent and severity (possibly close to moderate) by Tuesday.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory from 2 am Monday to 6 am edt Tuesday for
anz530-531-538-539.

Small craft advisory until 6 am edt Tuesday for anz532>534-536-
537-541>543.

Small craft advisory from 6 pm Monday to 6 am edt Tuesday for
anz535.

Small craft advisory from 6 pm this evening to 6 am edt
Tuesday for anz540.

Synopsis... Dhof
near term... Dhof
short term... Dhof
long term... Jmg
aviation... Dhof jmg
marine... Dhof jmg
hydrology... Dhof
tides coastal flooding... Dhof


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 18 mi44 min 63°F 72°F1022.4 hPa (-0.3)
NCDV2 21 mi44 min 65°F 74°F1020.5 hPa (-0.9)
BSLM2 - Chesapeake Bay, MD 25 mi134 min NE 1.9 60°F 1022 hPa59°F
44062 - Gooses Reef, MD 38 mi44 min E 16 G 19 65°F 75°F1022 hPa (-0.5)
SLIM2 - 8577330 - Solomons Island, MD 41 mi44 min 64°F 77°F1020.8 hPa (-1.2)
COVM2 - 8577018 - Cove Point LNG Pier, MD 42 mi44 min 64°F 1021.9 hPa (-1.0)
TPLM2 - Thomas Point, MD 42 mi44 min ENE 13 G 15 63°F 73°F1023 hPa (-0.8)62°F
APAM2 - 8575512 - Annapolis, MD 43 mi44 min 64°F 1022 hPa (-0.8)
PPTM2 - 8578240 - Piney Point, MD 46 mi80 min ENE 8.9 G 9.9
CPVM2 47 mi44 min 63°F 62°F

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA8 mi1.8 hrsN 010.00 miLight Drizzle64°F0°F%1022.6 hPa
Quantico Marine Corps Airfield - Turner Field, VA12 mi51 minENE 910.00 miLight Rain66°F64°F93%1022.1 hPa
Washington/Reagan National Airport, DC, VA17 mi52 minNNE 108.00 miLight Rain64°F61°F90%1022.3 hPa
Camp Springs / Andrews Air Force Base, MD20 mi1.8 hrsNNE 73.00 miLight Rain Fog/Mist63°F61°F96%1022.6 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA22 mi48 minNNE 510.00 miOvercast62°F61°F96%1023.3 hPa
Stafford, Stafford Regional Airport, VA23 mi69 minENE 54.00 miDrizzle65°F65°F100%1023 hPa

Wind History from DAA (wind in knots)
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Last 24hrCalmN4N5CalmCalmCalmCalmCalmCalmCalmCalmCalmNW3CalmCalmCalmNW5CalmN3CalmNE3CalmCalmN3
1 day agoSE4SE3--SE3------------S3S3--Calm----NW5NW4NW5NW9NW6------
2 days agoSE8SE6SE5SE5SE5SE5SE8SE7S5SE5S5CalmSE3SE3SE4SE3CalmS3S6SE4SE8SE6----

Tide / Current Tables for Glymont, Potomac River, Maryland
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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 Mount Vernon, Virginia
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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    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 (16,3,4,5)
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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.