Tuesday, September26, 2017 L-36.com


Marine Weather and Tides
North Chevy Chase, MD

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 6:59AMSunset 6:59PM Tuesday September 26, 2017 2:08 PM EDT (18:08 UTC) Moonrise 12:00PMMoonset 10:11PM Illumination 35% Phase: Waxing Crescent; Moon at 6 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- 132 Pm Edt Tue Sep 26 2017
This afternoon..NE winds 5 kt. Waves less than 1 ft.
Tonight..N winds 5 kt. Waves less than 1 ft.
Wed..N winds 5 to 10 kt. Waves 1 ft.
Wed night..N winds 5 to 10 kt. Waves 1 ft.
Thu..N winds 10 kt. Waves 1 ft.
Thu night..N winds 5 to 10 kt. Waves 1 ft.
Fri..NW winds around 5 kt. Waves 1 ft or less.
Sat..N winds 5 to 10 kt. Waves 1 ft.
ANZ500 132 Pm Edt Tue Sep 26 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will weaken overhead through Wednesday as hurricane maria drifts north to northeast off the north carolina coast. A cold front will pass through the area Thursday and a reinforcing cold front will pass through late Friday into early Saturday. High pressure will return for the weekend. Small craft advisories may be needed Wednesday night and gale force winds are possible Thursday. Small craft advisories may be needed again Friday night into Saturday. Refer to the national hurricane center for up-to-date information on hurricane maria.

7 Day Forecast for Marine Location Near North Chevy Chase, MD
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location: 39, -77.09     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 261415 aaa
afdlwx
area forecast discussion... Updated
national weather service baltimore md washington dc
1015 am edt Tue sep 26 2017

Synopsis
High pressure will slowly weaken its grip over the area today
and Wednesday as hurricane maria stalls in the western
atlantic. A cold front will move through Thursday, bringing
seasonable temperatures from late this week through early next
week. The front will also push hurricane maria out to sea.

Little if any rain is expected through early next week.

Near term through tonight
It appears any showers associated with far outer rain bands of
maria will remain well southeast of the area. Low clouds will
remain the main impact from maria for areas along and east of
the i-95 corridor. This should keep temps a couple of degs
cooler than yesterday. No precip is expected.

Previous discussion...

tonight, maria will remain off the nc coast. A few showers may
reach southern md, but again, odds are not high. We could see
more clouds advect in as well from the east, while inland could
see more patchy fog. All in all, not much different from what
we've seen lately. Lows mainly in the 60s.

Short term Wednesday through Thursday night
Maria will start turning east away from the region late
Wednesday, so we will still see some clouds especially in
eastern areas from it on Wednesday, and perhaps a stray shower
in southern md. Otherwise, we likely end up a bit warmer
Wednesday as clouds should overall be reduced as the storm
begins turning out to sea. Highs mainly 80s, but a few degrees
above today.

Strong cold front moves in early Thursday, with a pretty strong
breeze expected. However, with limited moisture and dynamics,
don't expect any showers with the front at this time. Humidity
will lower and highs may actually fail to reach 80 for the first
time in quite a few days. Skies will turn out mostly sunny.

Significantly cooler with diminishing wind Thursday night, with
40s and low 50s common.

Long term Friday through Monday
Overnight model guidance appears to have continued its trend of
a quicker weaker upper trough crossing the region Friday night
into Saturday. This appears to be in response to a stronger
upper low moving into western noam which shoves everything
downstream eastward quicker. The trough axis surface reflection
in the form of a reinforcing cold front are now progged to pass
through our area during the overnight hours. This decreases
further the chance for appreciable rainfall. Behind the front,
an autumnal high of canadian origins (~1030 mb) builds north of
the area bringing cooler and drier air through the weekend.

The tendency of lower heights over the western CONUS would tend
to support a stronger ridge developing over the middle portion
of the country. This ridge then builds towards the eastern conus
during the first part of next week. This results in a very low
chance of rain.

In fact, the last several runs of the GEFS have shown a very
strong negative pna during this time which would suggest strong
to extreme ridging building over the eastern CONUS in the
extended. Operational ECMWF not as extreme but its ensembles
agree with the idea of a strongly negative pna pattern early
next week. By extrapolation, this could lead to significantly
warmer than normal temperatures by the middle of next week.

However, the position of the (~1040 mb) surface high over
southeastern canada could keep a cooler wedge of air near the
surface offsetting the anomalously high heights aloft through at
least Tuesday.

Aviation 14z Tuesday through Saturday
MVFR CIGS at dca and bwi through early afternoon then improve to
vfr. Another round of low clouds and fog is possible tonight,
with a return toVFR likely again on Wednesday afternoon. By
Thursday, a strong cold front will bring gusty northwest winds,
preventing any more ifr or even MVFR conditions, even in the
morning. No more than a very isolated shower is expected through
the next few days.

MainlyVFR fri-sat. N winds 10 kts, a few gusts sat.

Marine
Sca over middle bay and adjancent waterways through Wednesday
with maria hanging off the coast. Then, strong cold front will
likely bring SCA to all waters Thursday, and potential for gales
remains with this front. Winds start diminishing late Thursday.

Northerly surge in cool dry advection early Saturday will
likely lead to a period of SCA conditions.

Tides coastal flooding
Water levels will remain elevated through midweek before a cold
frontal passage turns winds northerly and pushes excess water
out the mouth of the bay on Thursday.

Lwx watches warnings advisories
Dc... None.

Md... Coastal flood advisory until 10 pm edt this evening for mdz017.

Va... None.

Wv... None.

Marine... Small craft advisory from midnight tonight to 6 pm edt
Wednesday for anz533-541-542.

Small craft advisory until 6 pm edt Wednesday for anz534-537-
543.

Update... Lfr
products... Rcm dfh


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 10 mi50 min ENE 2.9 G 8 79°F 77°F1015.6 hPa
BSLM2 - Chesapeake Bay, MD 25 mi158 min N 1.9 67°F 1017 hPa63°F
APAM2 - 8575512 - Annapolis, MD 32 mi50 min 74°F 1015.2 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 33 mi50 min ESE 7 G 8 73°F 1015.7 hPa
BLTM2 - 8574680 - Baltimore, MD 33 mi50 min SSE 2.9 G 7 79°F 80°F1015.2 hPa
44063 - Annapolis 34 mi38 min NE 9.7 G 12 73°F 1015.1 hPa
TPLM2 - Thomas Point, MD 35 mi68 min N 11 G 12 71°F 77°F
CPVM2 37 mi50 min 74°F 73°F
44043 - Patapsco, MD 39 mi38 min NE 5.8 G 7.8 72°F 1016.6 hPa
44062 - Gooses Reef, MD 47 mi38 min N 14 G 16 73°F 1016.3 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 47 mi50 min N 8 G 9.9 73°F 77°F1016.2 hPa
NCDV2 47 mi50 min N 2.9 G 6 74°F 79°F1014.2 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
College Park Airport, MD9 mi83 minNNE 310.00 miFair77°F67°F71%1015.9 hPa
Washington/Reagan National Airport, DC, VA10 mi76 minENE 910.00 miOvercast80°F69°F69%1015.9 hPa
Gaithersburg - Montgomery County Airport, MD12 mi72 minVar 410.00 miFair80°F66°F64%1018.7 hPa
Camp Springs / Andrews Air Force Base, MD17 mi70 minN 610.00 miOvercast73°F66°F80%1016.4 hPa
Fort Meade / Tipton, MD18 mi83 minNE 410.00 miFair77°F68°F74%1016.9 hPa
Washington/Dulles International Airport, DC, VA19 mi76 minNE 610.00 miMostly Cloudy83°F68°F61%1015.7 hPa
Fort Belvoir, VA19 mi72 minN 010.00 miPartly Cloudy78°F66°F68%1015.8 hPa

Wind History from CGS (wind in knots)
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Last 24hrE3E5E3E4CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmN3CalmCalmCalmE4E3E5E4NE5
1 day agoN3E3NE3E3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmN3
2 days agoN7
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N4N4NW4CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmE4Calm

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Tue -- 01:15 AM EDT     3.26 feet High Tide
Tue -- 07:00 AM EDT     Sunrise
Tue -- 08:15 AM EDT     0.58 feet Low Tide
Tue -- 12:59 PM EDT     Moonrise
Tue -- 01:53 PM EDT     2.89 feet High Tide
Tue -- 06:58 PM EDT     Sunset
Tue -- 07:53 PM EDT     0.52 feet Low Tide
Tue -- 11:12 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
33.33.22.72.21.61.10.80.60.71.21.92.52.82.92.72.11.50.90.60.50.71.11.9

Tide / Current Tables for Chain Bridge, one mile below, Washington, D.C.
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Chain Bridge
Click for Map
Tue -- 01:06 AM EDT     3.24 feet High Tide
Tue -- 06:59 AM EDT     Sunrise
Tue -- 08:08 AM EDT     0.60 feet Low Tide
Tue -- 12:59 PM EDT     Moonrise
Tue -- 01:44 PM EDT     2.85 feet High Tide
Tue -- 06:58 PM EDT     Sunset
Tue -- 07:43 PM EDT     0.53 feet Low Tide
Tue -- 11:12 PM EDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.13.23.12.62.11.510.70.60.71.21.92.52.82.82.621.40.90.60.50.71.22

Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Mid-Atlantic    EDIT
Geos

Wind Forecast for Baltimore, MD/Washington (14,3,4,5)
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Ground Weather Radar Station Sterling, VA
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weather_mapweather_map weather_map

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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.