Thursday, February20, 2020
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Marine Weather and Tides
Halfway, MD

Version 3.4
NOTICE
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.

Sunrise 6:55AMSunset 5:53PM Thursday February 20, 2020 9:37 PM EST (02:37 UTC) Moonrise 5:23AMMoonset 3:02PM Illumination 7% Phase: Waning Crescent; Moon at 27 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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ANZ538 Patapsco River Including Baltimore Harbor- 637 Pm Est Thu Feb 20 2020
.small craft advisory in effect through Friday morning...
Tonight..NE winds 5 kt...becoming N 15 kt with gusts to 20 kt late this evening and overnight. Waves 1 ft or less. Scattered flurries this evening.
Fri..NW winds 5 to 10 kt. Gusts up to 20 kt until late afternoon. Waves 1 ft.
Fri night..W winds 5 kt. Waves flat.
Sat..W winds 5 to 10 kt. Waves 1 ft.
Sat night..W winds 5 kt. Waves flat.
Sun..SW winds 5 kt. Waves flat.
Sun night..S winds around 5 kt. Waves flat.
Mon..S winds 5 to 10 kt. Waves 1 ft or less. A chance of showers.
Tue..W winds 5 kt. Waves less than 1 ft. Showers likely through the day, then a chance of showers through the night.
ANZ500 637 Pm Est Thu Feb 20 2020
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will pass off the coast of the southeastern united states this evening. High pressure will build west of the area through the weekend.


7 Day Forecast for Marine Location Near Halfway, MD
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location: 39.62, -77.79     debug


Area Discussion for - Baltimore, MD/Washington
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FXUS61 KLWX 210206 AFDLWX

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 906 PM EST Thu Feb 20 2020

SYNOPSIS. Low pressure will pass out to sea well to the south tonight. High pressure will build in from the central United States through the weekend. A couple of low pressure systems will follow during the first half of next week.

NEAR TERM /UNTIL 6 AM FRIDAY MORNING/. Latest analysis shows a southern stream low over the western Florida Panhandle, and a northern stream mid/upper trough moving southward across Pennsylvania. The southern stream low will move offshore of the Carolinas tonight, and the northern edge of its precipitation field may clip portions of central Virginia to southern Maryland with mainly light scattered snow showers or flurries. The outer shield of precipitation from the low passing to our south has remained just to the south of our forecast area. A few flurries were reported in southern Maryland and parts of our southern bay. Large dewpoint depressions have helped limit the amount of snow reaching the ground and only a few flurries are possible over the next few hours for parts of southern Maryland.

Temperatures will take a tumble after midnight as northerly winds behind the departing systems gust 20 to 30 MPH.

SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/. High pressure will build into the region Friday into Friday night. This high is of Arctic origin, so below normal temperatures are expected. Brisk conditions are likely Friday morning before winds diminish through the afternoon hours.

Radiational cooling is likely Friday night with a clear sky, light winds and a dry air mass. The low temperature forecast for Friday night may need to be adjusted downward in subsequent forecast updates.

Temperatures will moderate Saturday as the core of the transient cold air mass pulls away.

LONG TERM /SUNDAY THROUGH THURSDAY/. High pressure will be in control Sunday. Dry conditions and mild temperatures are expected with plenty of sun. High pressure moves offshore Sunday night to allow for a southerly flow ahead of a low pressure system over the Middle Mississippi Valley.

Monday should start out dry with a continuation of mild temperatures as the southerly flow increases. Midday into the afternoon, clouds and rain chances will likely increase.

Rain chances linger Monday night into Tuesday as an associated cold front extending from the low pressure system moves across the region. Temperatures should be average at best with the additional cloud cover and rain showers. Model thicknesses suggest a little sleet could mix in at the onset, especially over the higher terrain.

Models are indicating that the cold front could slow its forward progress or perhaps stall to the east of our region Wednesday. This could set the stage for more unsettled weather. The 12Z ECMWF and some ensemble members develop another area of moderately strong low pressure near or over our area.

Once the front moves to our east, another strong cold high pressure will build in, likely bringing dry conditions and below normal temperatures once again later next week.

AVIATION /02Z FRIDAY THROUGH TUESDAY/. VFR expected through the TAF period. A scattered snow shower may approach CHO through 01Z. A flurry can't be ruled out further north, but visibility restrictions are not anticipated on a widespread or persistent basis (though some upstream observations in Pennsylvania have briefly dropped to IFR).

Northerly flow will increase late this evening after 03Z through just after daybreak, gusting 20 to 25 knots. Winds will gradually diminish through the day Friday. Mainly VFR is expected to persist through the weekend with generally light westerly flow.

VFR conditions expected Sunday. Sub-VFR possible Monday.

MARINE. A flurry or snow shower can't be ruled out this evening. Light northeast flow will become north late this evening and begin gusting 20 to 30 knots. Gusty winds will persist until just after daybreak Friday before gradually diminishing through the day as high pressure builds in.

Light westerly flow and dry conditions are expected Saturday as high pressure continues to build overhead.

No marine hazards are expected Sunday into Monday, though winds may begin increasing ahead of approaching low pressure by Monday night.

LWX WATCHES/WARNINGS/ADVISORIES. DC . None. MD . None. VA . None. WV . None. MARINE . Small Craft Advisory until 11 AM EST Friday for ANZ530>532- 538>540. Small Craft Advisory until 3 PM EST Friday for ANZ533-534-537- 541>543. Small Craft Advisory until 8 AM EST Friday for ANZ535-536.

SYNOPSIS . DHOF NEAR TERM . DHOF/JMG SHORT TERM . DHOF LONG TERM . KLW AVIATION . KLW/DHOF MARINE . KLW/DHOF


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 66 mi49 min N 7 G 9.9 38°F 44°F1030.2 hPa
BLTM2 - 8574680 - Baltimore, MD 69 mi55 min NE 9.9 G 14 35°F 43°F1030 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 72 mi49 min NNE 11 G 13 35°F 1030.3 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD7 mi44 minNNW 610.00 miMostly Cloudy29°F12°F51%1032.1 hPa
Eastern WV Regional Airport/Shepherd Field, WV18 mi44 minN 10 G 1610.00 miA Few Clouds30°F16°F56%1031.1 hPa

Link to 5 minute data for KHGR

Wind History from HGR (wind in knots)
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Last 24hrW3W4W4NW5NW5N3N5N3N4NW4N4N6N5N743NW4N7NW5N9N11N6N8NW6
1 day agoCalmNW3NW10NW6NW12NW16NW13NW11NW13NW7W3NW13W11NW19
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2 days agoSE12--SE5S9SE11S13S12SE9S8S5S7SE10S12S10S11S8S7CalmN8NW7N3CalmNW5Calm

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Thu -- 12:35 AM EST     -0.00 feet Low Tide
Thu -- 05:18 AM EST     Moonrise
Thu -- 06:09 AM EST     2.56 feet High Tide
Thu -- 06:54 AM EST     Sunrise
Thu -- 12:38 PM EST     0.03 feet Low Tide
Thu -- 03:01 PM EST     Moonset
Thu -- 05:50 PM EST     Sunset
Thu -- 06:30 PM EST     2.84 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.100.51.11.82.32.62.41.91.40.90.40.10.10.51.21.92.52.82.82.421.51

Tide / Current Tables for Chain Bridge, Washington, D.C.
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Weather Map
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wmap_A
GEOS Local Image of Mid-Atlantic    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.
Link to Loop



Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Baltimore, MD/Washington (21,6,7,8)
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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 numerous 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.