Friday, June23, 2017 L-36.com


Marine Weather and Tides
Mount Vernon, VA

Version 3.4
What's New / NOTES
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 5:43AMSunset 8:38PM Friday June 23, 2017 1:22 PM EDT (17:22 UTC) Moonrise 4:25AMMoonset 7:09PM Illumination 0% Phase: New Moon; 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
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ANZ535 Tidal Potomac From Key Bridge To Indian Head- 1125 Am Edt Fri Jun 23 2017
.small craft advisory in effect through Saturday afternoon...
Rest of today..SW winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft. Isolated showers late this morning, then isolated showers and tstms this afternoon.
Tonight..SW winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft. Showers with a chance of tstms. Vsby 1 nm or less.
Sat..W winds 10 kt with gusts to 20 kt. Waves 1 ft. Showers likely. Vsby 1 nm or less.
Sat night..NW winds 5 to 10 kt. Gusts up to 20 kt in the evening. Waves 1 ft.
Sun..W winds 5 to 10 kt. Waves 1 ft.
Sun night..NW winds 5 to 10 kt. Waves 1 ft.
Mon..NW winds around 5 kt. Waves 1 ft.
Tue..NW winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 1125 Am Edt Fri Jun 23 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will remain offshore today while a cold front slowly approaches from the northwest. The remnants of cindy will track along the front tonight, with the front finally pushing through on Saturday. A weak secondary front will cross Sunday before high pressure returns early next week. Small craft advisory conditions are possible Sunday.

7 Day Forecast for Marine Location Near Mount Vernon, VA
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location: 38.68, -77.1     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 231430
afdlwx
area forecast discussion
national weather service baltimore md washington dc
1030 am edt Fri jun 23 2017

Synopsis
Tropical air will envelop the area today. A cold front will
cross the area late tonight into Saturday. High pressure will
return Sunday and persist through early next week.

Near term until 6 pm this evening
The initial round of showers have exited to the eastern shore.

There are a few echoes on radar at this time. Its a little
better organized in southern west virginia westward, and this
streak will be headed toward central virginia during the midday
hours, supported by many cams. Don't believe daytime heating
will allow atmosphere to reach its full potential by that time,
although there is a fairly sizeable break in the clouds across
virginia at this time. Anticipate scattered showers and perhaps
a few thunderstorms. This may assist in keeping atmosphere
somewhat stable... Relatively speaking.

A modified sounding suggests that there will be a decent amount
of instability present by mid-afternoon... SBCAPE 1500 j kg,
mlcape 1000 j kg. More troubling is 30-40 kt of shear present on
12 utc raob, with a speed MAX yet to pass through. Ensembles
suggest a peak of instability and shear mid-late afternoon,
while GFS rap both insist cap will strengthen during this time.

That will be the key; if cap can be broken, the strong storms
will result. Am keeping low-end pops in the forecast through the
afternoon.

Short term 6 pm this evening through Sunday night
There is fairly good agreement between guidance of tracking the
remnant circulation of cindy across the central portion of the
cwa late tonight. That will represent the main chance of
moderate to heavy rainfall, though it's possible some lines of
storms could slowly drop south from pa during the evening and
prolong the issue over far NW sections of the area. Highest qpf
amounts will be to the northwest of the low track. Current
consensus still places this within the cwa, though some models
keep it to the northwest. The combination of uncertainty with
rain amounts today, along with where the axis of heaviest rain
tonight will be, gives low confidence on whether there will be
flash flood issues. However, the moisture-rich environment and
warm rain processes will be in play, so this situation will need
to be monitored closely. Current guidance also indicates stable
low levels tonight with meager instability, but winds aloft
will be very strong (with very high low level shear), so still
will not totally rule out an isolated instance of severe weather
just southeast of the low.

Low will be exiting quickly Saturday morning, taking the
heavier rain with it. However, the other player in all this --
the cold front -- does not look like it will completely push to
the southeast until later in the afternoon. Have maintained
chances for showers and storms east of i-95. Drying will
continue to advect in overnight, leading to less muggy lows.

A secondary cold front will drop through the area Sunday,
although it should remain precipitation-free. Highs will fall
back into the lower to mid 80s, with lows Sunday night in the
mid 50s to lower 60s.

Long term Monday through Thursday
The weather will feel more like late may than late june for
at least the first half of next week as a trough of upper level
low pressure settles over the region and a surface high sets up
to the west, funneling cooler and less humid canadian air
across our region. Temperatures will be several degrees below
normal, with highs in the 70s to lower 80s and lows in the 50s
to lower 60s. By this time of year, normal highs are in the mid-
upper 80s and normal lows are in the mid-upper 60s.

A weak cold front crossing the area, reinforcing the cooler and
drier air, may spark off a shower or t-storm late Monday into
early Tuesday. Otherwise, the period looks generally dry.

The trough will swing east of the region late in the week and
the surface high will return to a more typical bermuda-high
position, allowing warmer and more humid air to start returning
to the region.

Aviation 14z Friday through Tuesday
Still have some MVFR ceiling across the baltimore-washington
terminals from this morning's rain. However, there is a large
break in the clouds across virginia. Therefore,VFR conditions
are expected by late morning and will persist through the
afternoon, though SW winds may gust to 20 kt. Thunderstorm
development this afternoon is conditional this afternoon with a
cap in place. Guidance has little to no coverage, so will limit
mention. Main restrictions will come tonight as remnants of
cindy cross the area. MVFR to possibly ifr will occur late
tonight, but exit quickly Saturday morning. Cold front may not
clear the area until afternoon, though chance of additional
showers storms is low.

Second cold front will cross on Sunday with little to no
impact.

Vfr expected Monday and Tuesday. An isolated shower or
thunderstorm can't be ruled out late Monday into early Tuesday
with a weak cold front, but odds are low.

Marine
Winds will increase in earnest later this morning once mixing
can increase; SCA remains in effect. Any thunderstorms this
afternoon should be isolated. May be a lull in the winds
tonight, but will increase south of the low track of the
remnants of cindy. Have extended the SCA through Saturday as
cold front pushes through the area, although winds may decrease
by mid afternoon as gradient weakens. Second cold front will
cross on Sunday and winds may marginally reach SCA levels.

A weak cold front crossing the area late Monday into early
Tuesday could boost winds up to SCA levels. An isolated shower
or thunderstorm is also possible with this front.

Hydrology
This morning's rain produced a tenth to a third of an inch,
which won't have a big impact with respect to antecedent
conidtions.

Highest total QPF still looks to remain across the NW parts of
the area where 1-2 inches total will be possible. However, there
is still considerable uncertainty, especially since preceding
events may underproduce, and thunderstorms could produce local
variations. With areal averages spread out over the period,
mmefs continues to indicate no potential of mainstem river
flooding. The main concern will be flash flooding in any areas
which receive repeated and or prolonged periods of heavy rain.

Again, that would be the mountains, primarily tonight into
Saturday morning.

Tides coastal flooding
Water levels remain near astronomical normals. While an increase
is anticipated through Friday, flow will remain southwest. As
such, flooding is not likely. However, caution action stages
will be reached today, and any small deviation could bring the
sensitive spots to minor.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory until 6 pm edt Saturday for anz530>543.

Synopsis... Rcm
near term... Hts
short term... Ads
long term... Rcm
aviation... Hts ads rcm
marine... Ads rcm
hydrology... Hts ads
tides coastal flooding... Hts rcm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
44061 - Upper Potomac, MD 8 mi64 min WSW 18 G 19 79°F 82°F1009.3 hPa
WASD2 - 8594900 - Washington, DC 14 mi52 min SW 7 G 13 85°F 83°F1008 hPa
BSLM2 - Chesapeake Bay, MD 22 mi112 min SSW 8.9 77°F 1009 hPa71°F
NCDV2 25 mi52 min WSW 15 G 18 84°F 80°F1008.6 hPa
44062 - Gooses Reef, MD 37 mi42 min W 16 G 21 82°F 1009.8 hPa
TPLM2 - Thomas Point, MD 38 mi82 min SSW 13 G 15 80°F 78°F
APAM2 - 8575512 - Annapolis, MD 39 mi52 min 86°F 1007.9 hPa
44063 - Annapolis 40 mi42 min SW 14 G 16 82°F 1008.6 hPa
SLIM2 - 8577330 - Solomons Island, MD 42 mi52 min WSW 16 G 20 82°F 77°F
COVM2 - 8577018 - Cove Point LNG Pier, MD 42 mi52 min W 15 G 20 82°F 1010.3 hPa
CPVM2 44 mi52 min 81°F 75°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 48 mi52 min SW 13 G 15 82°F 1007.6 hPa
FSNM2 48 mi52 min SW 5.1 G 13 82°F 1008.1 hPa
PPTM2 - 8578240 - Piney Point, MD 48 mi52 min W 13 G 18
BLTM2 - 8574680 - Baltimore, MD 49 mi52 min WSW 6 G 11 83°F 81°F1007.5 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Fort Belvoir, VA5 mi84 minS 510.00 miPartly Cloudy85°F73°F68%1009.4 hPa
Washington/Reagan National Airport, DC, VA13 mi30 minSW 1710.00 miMostly Cloudy88°F73°F63%1008.6 hPa
Quantico Marine Corps Airfield - Turner Field, VA16 mi86 minSW 8 G 1710.00 miMostly Cloudy85°F73°F70%1009.8 hPa
Camp Springs / Andrews Air Force Base, MD16 mi24 minSSW 18 G 2410.00 miPartly Cloudy and Breezy86°F72°F63%1009.2 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA22 mi26 minSW 9 G 1410.00 miFair82°F73°F74%1009.9 hPa
College Park Airport, MD23 mi29 minWSW 510.00 miPartly Cloudy86°F72°F65%1008.5 hPa

Wind History from DAA (wind in knots)
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Last 24hrSW4W5SW5S4SW4S4S3CalmCalmCalmSE3CalmS4S3CalmCalmSW3SW3SE3S5S7S5S6
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1 day agoSW4NW6W7S5S5S6S4CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS3CalmS3CalmS6
2 days agoSW6W5W5S6S7S10
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S9S4SE3CalmS4CalmCalmS3S3CalmCalmCalmCalmS6SW3S6S8S6

Tide / Current Tables for Marshall Hall, Potomac River, Maryland
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Marshall Hall
Click for Map
Fri -- 01:24 AM EDT     0.12 feet Low Tide
Fri -- 05:25 AM EDT     Moonrise
Fri -- 05:44 AM EDT     Sunrise
Fri -- 07:38 AM EDT     3.07 feet High Tide
Fri -- 02:27 PM EDT     -0.03 feet Low Tide
Fri -- 08:08 PM EDT     Moonset
Fri -- 08:19 PM EDT     2.57 feet High Tide
Fri -- 08:36 PM EDT     Sunset
Fri -- 10:32 PM EDT     New Moon
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.40.10.20.51.222.7332.721.40.80.4000.41.11.82.32.62.521.3

Tide / Current Tables for High Point, Occoquan Bay, Virginia
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High Point
Click for Map
Fri -- 12:49 AM EDT     0.07 feet Low Tide
Fri -- 05:26 AM EDT     Moonrise
Fri -- 05:45 AM EDT     Sunrise
Fri -- 06:41 AM EDT     2.13 feet High Tide
Fri -- 01:50 PM EDT     -0.04 feet Low Tide
Fri -- 07:21 PM EDT     1.79 feet High Tide
Fri -- 08:08 PM EDT     Moonset
Fri -- 08:37 PM EDT     Sunset
Fri -- 10:32 PM EDT     New Moon
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.10.10.20.71.31.82.12.11.91.510.70.30.1-00.20.71.21.61.81.71.410.6

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 (13,3,4,5)
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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.