Sunday, May28, 2017 L-36.com


Marine Weather and Tides
Williamsport, MD

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 5:44AMSunset 8:31PM Sunday May 28, 2017 6:34 AM EDT (10:34 UTC) Moonrise 7:47AMMoonset 10:32PM Illumination 9% Phase: Waxing Crescent; Moon at 3 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- 432 Am Edt Sun May 28 2017
Rest of the overnight..NE winds 5 kt. Waves less than 1 ft.
Today..SE winds around 5 kt. Waves 1 ft. A chance of showers. Patchy fog. Vsby 1 to 3 nm.
Tonight..SE winds 5 to 10 kt. Waves 1 ft. Showers likely with a chance of tstms.
Mon..W winds 5 kt. Waves less than 1 ft.
Mon night..NW winds around 5 kt. Waves 1 ft.
Tue..SW winds around 5 kt. Waves 1 ft. A chance of showers.
Tue night..W winds 5 kt. Waves less than 1 ft.
Wed..W winds 5 to 10 kt. Waves 1 ft.
Thu..S winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 432 Am Edt Sun May 28 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A nearly stationary front will extend across the mid atlantic region before a cold front moves into the area Monday. Weak high pressure can be expected Tuesday, followed by another weak front on Wednesday. High pressure will return on Thursday.

7 Day Forecast for Marine Location Near Williamsport, MD
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location: 39.58, -77.81     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 280802
afdlwx
area forecast discussion
national weather service baltimore md washington dc
402 am edt Sun may 28 2017

Synopsis A surface trof will move across the area tonight
followed by a weak cold front Monday afternoon. Upper level low
pressure will linger north of the great lakes Monday night
through the remainder of the week with persistent weak high
pressure over the mid-atlantic.

Near term through tonight Dense fog has formed across the
northern part of the fcst area with many sites reporting less
than a quarter mile visibility.

For today, weak sfc front trof will get hung up across the area
today and this evening with models indicating decent sfc
convergence across the NRN part of the fcst area. A shortwave-
trough will move across the area this evening and help trigger
numerous to widespread showers and t-storms. Overall, trend in
the models and ensembles the past 24 hrs is for weaker sfc
convergence and less QPF than yesterday. Despite this, there is
still some concern for flash flooding mainly across the far
northwest part of the fcst area where sfc convergence lift will
be strongest and a plume of 1.5+ inches of pw will advect in.

1-2 inch hourly rain rates can be expected with heaviest
showers. Isolated instances of flash flooding are possible
mainly across allegany, mineral, and grant counties. Think
severe threat will be more limited due to plenty of cloud cover
and weak instability below 1000 j kg.

Short term Monday through Tuesday night Things will calm
down somewhat as drier air filters in on westerly flow, but it
won't be completely dry. Still risk of showers t-storms tue
afternoon as a weak cdfnt moves through.

Long term Wednesday through Saturday
The upper level pattern for the middle and end of the week will
feature a closed low drifting across eastern canada. While
increasing model spread of this feature late in the week lends some
uncertainty, there is some signal in the noise.

On Wednesday, a weak cold front will be drifting south of the area.

There are some indications this front could waver, resulting in
lingering chances of showers, but eventually high pressure building
from the west should lead to higher probabilities of dry conditions.

Thursday has the highest probability of being dry this week. Return
flow will begin on Friday, although forcing instability aren't that
notable. A cold front will be sinking southward next weekend,
although progress will be slow since it will be parallel to the
upper flow. Thus an unsettled period appears probable, but timing is
uncertain.

Temperatures will settle close to normal behind the front on
Wednesday and Thursday, then warm back up (highs in the 80s) ahead
of the next front on Friday and Saturday.

Aviation 08z Sunday through Thursday Lifr conditions
through 12z today at kcho and kmrb due to dense fog. Then,
showers and t-storms this afternoon and evening with brief
MVFR ifr CIGS in t-storms with heavy rain.

Overall Wednesday should beVFR, but there is a small chance of
showers as a front sags south of the area. Winds could also gust
around 20 kt.VFR conditions are expected Thursday as high pressure
builds in from the west.

Marine Winds should remain below SCA through the first half
of the week, but higher winds and waves can be expected near
thunderstorms.

Depending on the position of a cold front, winds could near sca
levels on Wednesday but confidence is low. Lighter winds are
expected on Thursday as high pressure builds in from the west.

Tides coastal flooding Water anomalies will continue to rise
through 12z Mon with minor coastal flooding expected at many of
the coastal sites. Winds turn westerly on mon, but they will be
generally light and may not be able to lower anomalies that
much.

Lwx watches warnings advisories
Dc... Coastal flood advisory from 8 am this morning to 2 pm edt this
afternoon for dcz001.

Md... Dense fog advisory until 7 am edt this morning for mdz003>005-
501-502.

Coastal flood advisory until 10 am edt this morning for mdz014.

Coastal flood advisory until 8 pm edt this evening for mdz017.

Va... Dense fog advisory until 8 am edt this morning for vaz028-031.

Coastal flood advisory from 8 am this morning to 2 pm edt this
afternoon for vaz054.

Wv... Dense fog advisory until 8 am edt this morning for wvz053.

Dense fog advisory until 7 am edt this morning for wvz050>052-
504.

Marine... None.

Synopsis... Lfr
near term... Lfr
short term... Lfr
long term... Ads
aviation... Ads lfr
marine... Ads lfr
tides coastal flooding... Lfr


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 64 mi47 min NNE 1.9 G 4.1 62°F 68°F1011.1 hPa
BLTM2 - 8574680 - Baltimore, MD 69 mi47 min NNE 4.1 G 4.1 62°F 68°F1011.6 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 72 mi47 min NE 2.9 G 4.1 62°F 1011.8 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD10 mi42 minN 00.25 miFog58°F57°F97%1012.9 hPa
Eastern WV Regional Airport/Shepherd Field, WV15 mi42 minN 00.25 miFog58°F57°F97%1011.4 hPa

Wind History from HGR (wind in knots)
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Last 24hrE3CalmE4SW3CalmCalmCalmCalmN4NE6NW4CalmCalmNW3CalmCalmCalmCalmSE3NE3CalmCalmNW3Calm
1 day agoS5SW7W7W8NW9W11W13W6W11W12
G24
W11W11NW11NW15NW9NW7NW6CalmW3S3CalmSW4E3S3
2 days agoNE3N6NE6E8N3W34S33CalmE3E4E4N5SW5W5SW3SW4SW6W7SW5SW7SW6SW5

Tide / Current Tables for Chain Bridge, Washington, D.C.
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Chain Bridge
Click for Map
Sun -- 05:37 AM EDT     0.15 feet Low Tide
Sun -- 05:46 AM EDT     Sunrise
Sun -- 08:46 AM EDT     Moonrise
Sun -- 11:11 AM EDT     3.78 feet High Tide
Sun -- 06:30 PM EDT     -0.07 feet Low Tide
Sun -- 08:25 PM EDT     Sunset
Sun -- 11:27 PM EDT     Moonset
Sun -- 11:55 PM EDT     3.26 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
32.41.71.10.60.20.20.61.62.73.53.83.632.31.610.4000.61.62.53.1

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Sun -- 05:36 AM EDT     0.12 feet Low Tide
Sun -- 05:46 AM EDT     Sunrise
Sun -- 08:46 AM EDT     Moonrise
Sun -- 11:10 AM EDT     3.84 feet High Tide
Sun -- 06:28 PM EDT     -0.09 feet Low Tide
Sun -- 08:25 PM EDT     Sunset
Sun -- 11:27 PM EDT     Moonset
Sun -- 11:54 PM EDT     3.31 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.12.51.71.10.50.20.20.61.62.83.53.83.73.12.31.610.4-0-00.61.62.63.1

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 (6,6,7,8)
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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.