Thursday, August22, 2019 L-36.com


Marine Weather and Tides
Ashburn, VA

Version 3.4
NOTICE
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen

Sunrise 6:28AMSunset 7:57PM Thursday August 22, 2019 1:47 PM EDT (17:47 UTC) Moonrise 10:48PMMoonset 12:00PM Illumination 54% Phase: Third Quarter Moon; Moon at 22 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- 136 Pm Edt Thu Aug 22 2019
This afternoon..SW winds 5 to 10 kt. Waves 1 ft. Scattered showers and tstms.
Tonight..W winds around 5 kt. Waves 1 ft. Scattered showers and tstms.
Fri..N winds 5 kt. Waves less than 1 ft. A chance of showers.
Fri night..N winds around 5 kt. Waves 1 ft.
Sat..NE winds 5 kt. Waves less than 1 ft.
Sat night..NE winds 5 kt. Waves less than 1 ft.
Sun..NE winds 5 kt. Waves less than 1 ft.
Mon..E winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 136 Pm Edt Thu Aug 22 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front will approach the waters tonight, then stall over the carolinas on Saturday. High pressure will then settle over the area Saturday into Sunday. Small craft advisories are possible over the southern waters Friday night through Sunday .


7 Day Forecast for Marine Location Near Ashburn, VA
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location: 39.03, -77.47     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 221407 aaa
afdlwx
area forecast discussion... Updated
national weather service baltimore md washington dc
1007 am edt Thu aug 22 2019

Synopsis
A cold front will cross the area late tonight or
early Friday, then move into the carolinas over the weekend.

Canadian high pressure will build north of the region over the
weekend and hold through early next week.

Near term through tonight
Hot and humid conditions expected again today out ahead of an
approaching cold front and upper level trough. High temperatures
will peak in the low to mid 90s, with heat index values from the
mid 90s to low 100s. This warmth humidity will allow for the
development of 1000-2000 j kg of SBCAPE by this afternoon.

Currently monitoring ongoing convective system across central
west virginia. A general weakening trend will continue as it
progresses eastward over the next several hours, but a few
showers and isolated thunderstorms are possible across portions
of eastern WV and western va. The main catalyst for possible
convective activity across the region will likely be some upper
level energy moving east-northeastward out of kentucky this
morning, which will cross the region during the evening hours.

Convective allowing models are in general agreement of
convective initiation occurring across the higher terrain of
eastern WV and central western va during the mid to late
afternoon hours, with activity progressing eastward during the
evening hours. Given the SBCAPE mentioned above, in addition to
large amounts of dcape (>1000 j kg), and 20-30 knots of
effective shear, some isolated severe thunderstorms are
possible, with localized damaging winds likely the greatest
threat.

Some additional shower and thunderstorm activity will remain
possible overnight as a cold front will be crossing the area
late tonight into early Fri morning. Lows from the mid 60s to
low 70s.

Short term Friday through Saturday night
Showers and perhaps a few thunderstorms will remain possible
Friday especially in the morning as cdfnt sags southward. Severe
wx, if any, would be confined to eastern va and far southern md
chesapeake bay waters. Most of the showers should be gone by
midnight Fri night if nor earlier. Dry and much cooler weather
will establish for the weekend as high pressure builds from the
north.

Long term Sunday through Wednesday
High pressure will build into the region Sunday and linger
through Tuesday. Dry conditions and near average temperatures
are expected each day for most of our region. An onshore flow from
the western atlantic could spawn a few showers or a thunderstorm
Monday afternoon and again Tuesday afternoon, mainly in the upslope
areas and along the chesapeake bay.

The high pressure will move to the northeast Tuesday night and
Wednesday. A cold front will approach the region from the west. The
approaching front will allow for a southerly return flow to develop
and bring in more humid conditions and warmer temperatures.

Showers and thunderstorms will become more widespread, or at
least the chances will increase going into Wednesday.

One caveat to the extended forecast that could make or break our
region with a lot of showers and thunderstorms or dry through a
long stretch will be the possible coastal low, sub-tropical low,
or perhaps tropical low along the east coast Monday night through
Wednesday. Placement and intensity and timing are low confidence
factors so far with the possible low pressure system. Both the
european and GFS models hint of this low along the east coast and
mid-atlantic coast, but neither model has a direct impact on our
cwa. We will have to see what, if any, low develops and where it
moves over the next two to three days.

Aviation 14z Thursday through Monday
Scattered afternoon and early evening t-storms expected. Cdfnt
crosses the area late tonight or early fri. High pressure builds
for the weekend.

Vfr conditions for all terminals Sunday through Monday night. We
can't rule out a shower or thunderstorm near cho late Sunday
into Sunday night, or a shower or thunderstorm at any terminal
Monday afternoon. Winds northeast to east 5 to 10 knots
Sunday through Monday, becoming southeast 5 to 10 knots
Monday night.

Marine
Gusty t-storms possible late today or this evening may require
smws. Showers may linger across the southern waters all day fri.

No marine hazards expected Sunday through Monday night. Winds
northeast 10 knots Sunday through Monday, becoming east 10
knots Monday night.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... None.

Synopsis... Lfr
near term... Mm lfr
short term... Lfr
long term... Klw
aviation... Mm lfr klw
marine... Mm lfr klw


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 26 mi47 min W 5.1 G 9.9 89°F 84°F1013.9 hPa (-0.7)
BSLM2 - Chesapeake Bay, MD 44 mi137 min W 5.1 86°F 1014 hPa70°F
BLTM2 - 8574680 - Baltimore, MD 50 mi53 min W 2.9 G 9.9 88°F 85°F1012.9 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Washington/Dulles International Airport, DC, VA5 mi55 minNW 710.00 miMostly Cloudy89°F66°F47%1014.2 hPa
Leesburg / Godfrey, VA6 mi52 minW 7 G 15 miFair88°F69°F55%1015.2 hPa
Gaithersburg - Montgomery County Airport, MD19 mi51 minVar 510.00 miA Few Clouds86°F70°F59%1016 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA22 mi51 minW 810.00 miA Few Clouds92°F69°F47%1014.9 hPa

Link to 5 minute data for KIAD

Wind History from IAD (wind in knots)
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Last 24hrS7W5S9SW8NE6E5SE4CalmSE4SW3W4CalmCalmCalmCalmCalmS3CalmCalmCalmNW86W7NW7
1 day agoE4E7E4S18
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E5CalmCalmCalmS6SE4S5CalmS4CalmS5S5SW34SW6S4S5SE7
2 days agoNW8NW955NW6CalmE6CalmSW7E6
G17
CalmNE5W3CalmCalmNW3CalmNW3NW5N53NE5SE5S5

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
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Thu -- 01:20 AM EDT     3.22 feet High Tide
Thu -- 06:28 AM EDT     Sunrise
Thu -- 08:14 AM EDT     0.71 feet Low Tide
Thu -- 12:58 PM EDT     Moonset
Thu -- 01:47 PM EDT     2.87 feet High Tide
Thu -- 07:53 PM EDT     Sunset
Thu -- 08:05 PM EDT     0.45 feet Low Tide
Thu -- 11:46 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.93.23.22.82.31.71.20.90.70.81.11.72.42.82.92.72.21.71.10.60.50.50.91.5

Tide / Current Tables for Chain Bridge, one mile below, D.C.
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Chain Bridge
Click for Map
Thu -- 01:15 AM EDT     3.22 feet High Tide
Thu -- 06:28 AM EDT     Sunrise
Thu -- 08:09 AM EDT     0.71 feet Low Tide
Thu -- 12:58 PM EDT     Moonset
Thu -- 01:42 PM EDT     2.87 feet High Tide
Thu -- 07:53 PM EDT     Sunset
Thu -- 08:00 PM EDT     0.45 feet Low Tide
Thu -- 11:46 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.93.23.12.82.31.71.20.80.70.81.11.72.42.82.92.72.21.610.60.40.60.91.6

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 (13,3,4,5)
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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.