Saturday, July22, 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 6:00AMSunset 8:29PM Saturday July 22, 2017 4:50 PM EDT (20:50 UTC) Moonrise 4:08AMMoonset 6:52PM Illumination 1% Phase: Waning Crescent; Moon at 29 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
    EDIT      (on/off)   Help
ANZ535 Tidal Potomac From Key Bridge To Indian Head- 432 Pm Edt Sat Jul 22 2017
Rest of this afternoon..SW winds 10 kt. Waves 1 ft. Scattered showers and tstms. Vsby 1 nm or less.
Tonight..SW winds 5 kt. Waves less than 1 ft. Numerous showers and tstms.
Sun..W winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms.
Sun night..W winds 5 to 10 kt. Waves 1 ft. A chance of showers.
Mon..W winds 5 kt. Waves less than 1 ft.
Mon night..NW winds 5 kt. Waves less than 1 ft.
Tue..NE winds 5 kt. Waves less than 1 ft.
Wed..SE winds 5 kt. Waves less than 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 432 Pm Edt Sat Jul 22 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Light winds are expected with high pressure to the south through the weekend. Scattered Thunderstorms are expected each afternoon and evening. A cold front will move through Sunday night.

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


Area Discussion for - Baltimore, MD/Washington
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus61 klwx 221841
afdlwx
area forecast discussion
national weather service baltimore md washington dc
241 pm edt Sat jul 22 2017

Synopsis
High pressure remains off the southeast coast. Multiple upper
level disturbances will be possible through Sunday. An upper
level trough of low pressure will move over the northeastern us
early in the week.

Near term through tonight
Complex weather situation continues to unfold across the
area... As initial MCS is currently impacting the northern half
of the forecast area between dc and balt. Early arrival of qlcs has
tempered instability somewhat... Which has kept the strongest
updrafts rather isolated. Furthermore, poor mid- upper-level
lapse rates coupled with relatively weak shear have tended to
limit vertical parcel accelerations... And will likely keep
strongest winds more isolated-to-widely scattered. Greatest
threat for damaging wind over the next hour will reside across n
prince georges and anne arundel counties. While cloud cover
will likely limit additional heating out ahead of the
line... With MLCAPE values peaking near 1500 j kg... Modest cold
pool will allow for continued localized instances of wind gusts
aoa 50 kts as this activity continues to push east across that
area.

Storms that are developing and moving into the NW portion of the
area and across N WV will continue to sag into the area through
the evening. While the current line may work over much of the
northern half of the area, weak (but sufficient) instability
may lead to isolated instances of gusty winds with the most
vigorous activity as it crosses the area.

Precipitable water has surged to near 2 inches this... Which
would allow for locally heavy rainfall in the heaviest activity.

However, storm speeds should keep hydro threats generally
isolated. Though, a slightly greater threat could develop if
cell training allows for multiple rounds of heavy rainfall over
the same area.

Heat advisory also continues along and east of i-95 through
today. Cloud cover has tempered warming a bit... Keeping most
places just shy of the 105f heat index threshold. Though, multi-
day nature of threat justifies headline even if heat indices
only marginally meet the criteria.

Short term Sunday through Monday
Warm and humid weather Sunday as we continue to reside in the
warm sector and high temperatures remain in the 90s with
dewpoints in the 70s. Heat dome recedes just a bit to the SE as
heights fall... Which will keep the hottest temperatures across
central va... Where a heat advisory appears more likely.

Along east of i-95... Temperatures may be a degree or two cooler
than today... Though, prolonged nature of event, coupled with
heat indices near 100 to perhaps 105f, suggest that a heat
advisory may again be needed... Especially considering the
accumulated effect of the heat and humidity.

Convective evolution tomorrow rather muddled and will likely
depend on the spatiotemporal evolution of convection later
tonight (which will allow finer scale details to become more
clear). While CAPE shear parameters may become more favorable
than they are today (which would enhance storm organization), timing
and evolution will likely determine degree of coverage of the
strongest storm. Gusty winds and a few instances of large hail
are the primary hazards.

A cold front will approach the region Monday before pushing across
the region Monday night. Showers and thunderstorms will develop
along and ahead of this front... Some of which could be strong.

Highs will reach the 90s again.

Long term Monday night through Friday
A cold front should stall across the virginia and north carolina
border Tuesday, allowing for a few showers to linger across our
southern areas.

High pressure will build in from the west and northwest Tuesday
night and Wednesday. Temperatures will be nearly 10 degrees cooler
than previous days with a comfortable relative humidity.

The next cold front will arrive and push across the region Thursday
into Friday. Another active pattern of showers and thunderstorms
during the period and could linger into the weekend if the front
stalls across portions of the region.

A second area of high pressure will build in for the weekend,
bringing drier and cooler conditions.

Aviation 18z Saturday through Thursday
Vfr conditions will prevail through Monday... Outside of
thunderstorm activity. Multiple rounds of thunderstorms are
possible during this time (with the best chance during the
afternoons and evenings) with gusty winds and reduced
visibility in the strongest storms.

Vfr conditions expected Tuesday through Wednesday night. Winds north
10 knots Tuesday, becoming northeast 5 to 10 knots Tuesday night.

Winds light and variable Wednesday and Wednesday night.

Marine
Winds will remain below SCA values through Monday. However, strong
thunderstorms capable of producing gusty winds above special
marine warning criteria are possible late this afternoon and
evening and again Sunday Monday.

No marine hazards expected Tuesday through Wednesday night.

Winds becoming northwest 10 knots Tuesday, then northeast 5 to 10
knots Tuesday night. Winds light and variable Wednesday and
Wednesday night.

Lwx watches warnings advisories
Dc... Heat advisory until 7 pm edt this evening for dcz001.

Md... Heat advisory until 7 pm edt this evening for mdz011-013-014-
016>018-504-506.

Va... Heat advisory until 7 pm edt this evening for vaz052>057.

Wv... None.

Marine... None.

Synopsis... Mse
near term... Mse
short term... Mse
long term... Klw
aviation... Mse klw
marine... Mse klw


Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map
Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 10 mi51 min SW 1 G 1.9 87°F1009.7 hPa (-1.0)
BSLM2 - Chesapeake Bay, MD 25 mi141 min SW 4.1 89°F 1010 hPa70°F
APAM2 - 8575512 - Annapolis, MD 32 mi51 min 1009.3 hPa (-1.5)
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 33 mi51 min WSW 12 G 14 77°F 1009 hPa (-2.0)
BLTM2 - 8574680 - Baltimore, MD 33 mi51 min WSW 4.1 G 6 79°F 87°F1008.9 hPa (-1.7)
44063 - Annapolis 34 mi41 min W 7.8 G 9.7 78°F 1 ft1009.6 hPa
TPLM2 - Thomas Point, MD 35 mi51 min WNW 8.9 G 11 78°F 84°F
CPVM2 37 mi51 min 78°F 76°F
44043 - Patapsco, MD 39 mi41 min W 9.7 G 19 79°F 1 ft1010.1 hPa
44062 - Gooses Reef, MD 47 mi41 min ENE 14 G 16 80°F 2 ft1011.4 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 47 mi51 min W 19 G 22 82°F 87°F1009.7 hPa (-2.0)
NCDV2 47 mi51 min E 6 G 8 92°F 87°F1008.6 hPa (-2.4)

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
4
PM
Last
24hr
W5
NW2
G5
W1
S5
S1
S7
SW2
G5
NW4
NW5
NW5
G9
NW6
G10
NW8
NW4
NW5
NW4
G9
NW5
NW4
G8
W5
SW3
--
SW3
SW6
G11
N7
G14
SW1
1 day
ago
SW4
G8
SW5
SW5
G8
S8
S6
S6
SE4
G7
S5
NW2
NW6
G9
NW2
G5
NW3
NW1
NW1
NW4
NW4
NW6
G11
NW5
G9
W3
SW4
G7
S5
S6
E1
NW4
G7
2 days
ago
E1
S7
G10
--
SW5
S4
S7
S4
S4
G8
S4
S3
S3
SW2
S3
SW1
NW4
NW5
W5
NW6
NW7
G11
NW4
W5
G9
W2
G6
SW6

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
College Park Airport, MD9 mi63 minN 010.00 miMostly Cloudy74°F70°F90%1010.5 hPa
Washington/Reagan National Airport, DC, VA10 mi59 minW 510.00 miOvercast78°F73°F85%1010.5 hPa
Gaithersburg - Montgomery County Airport, MD12 mi55 minN 010.00 miA Few Clouds74°F71°F91%1012.9 hPa
Camp Springs / Andrews Air Force Base, MD17 mi53 minW 610.00 miLight Drizzle77°F71°F83%1010.6 hPa
Fort Meade / Tipton, MD18 mi63 minN 02.00 miOvercast72°F69°F94%1011.2 hPa
Washington/Dulles International Airport, DC, VA19 mi59 minN 010.00 miOvercast80°F70°F71%1010.2 hPa
Fort Belvoir, VA19 mi53 minN 010.00 miLight Rain80°F71°F73%1010.4 hPa

Wind History from CGS (wind in knots)
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
-12
PM
1
AM
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
4
PM
Last 24hrW4W3E3CalmCalmCalmN3CalmCalmCalmNW4NW5CalmNW3CalmN4NW5CalmCalmS3W6W6CalmCalm
1 day agoNW3CalmW3W3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmNW4N6NW7CalmCalmSW3S4W8W4
2 days agoCalmW5CalmNW4CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmW3W3SW5W6SW6SW6SW5W3W7

Tide / Current Tables for Chain Bridge, D.C.
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Chain Bridge
Click for Map
Sat -- 02:19 AM EDT     0.13 feet Low Tide
Sat -- 05:08 AM EDT     Moonrise
Sat -- 06:00 AM EDT     Sunrise
Sat -- 08:03 AM EDT     3.73 feet High Tide
Sat -- 03:16 PM EDT     -0.05 feet Low Tide
Sat -- 07:51 PM EDT     Moonset
Sat -- 08:28 PM EDT     Sunset
Sat -- 08:41 PM EDT     3.23 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.80.40.10.20.81.92.93.53.73.52.92.21.50.90.3-00.10.81.82.63.13.22.82.1

Tide / Current Tables for Chain Bridge, one mile below, Washington, D.C.
   EDIT      (on/off)   Help   One Week of Data
Chain Bridge
Click for Map
Sat -- 02:11 AM EDT     0.13 feet Low Tide
Sat -- 05:08 AM EDT     Moonrise
Sat -- 06:00 AM EDT     Sunrise
Sat -- 07:55 AM EDT     3.72 feet High Tide
Sat -- 03:10 PM EDT     -0.04 feet Low Tide
Sat -- 07:51 PM EDT     Moonset
Sat -- 08:28 PM EDT     Sunset
Sat -- 08:34 PM EDT     3.21 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.70.40.10.30.922.93.53.73.42.82.11.40.80.3-00.20.91.92.73.13.22.72

Weather Map and Satellite Images
       (on/off)   Help
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 (16,3,4,5)
      (on/off)   Help

Ground Weather Radar Station Sterling, VA
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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.