Saturday, April20, 2019 L-36.com


Marine Weather and Tides
Halfway, MD

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 6:24AMSunset 7:54PM Saturday April 20, 2019 12:19 PM EDT (16:19 UTC) Moonrise 8:26PMMoonset 6:28AM Illumination 99% Phase: Waning Gibbous; Moon at 16 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- 1053 Am Edt Sat Apr 20 2019
.small craft advisory in effect until 8 pm edt this evening...
Rest of today..S winds 15 kt with gusts to 25 kt. Waves 1 to 2 ft.
Tonight..S winds 10 to 15 kt with gusts to 20 kt... Becoming sw 5 kt after midnight. Waves 1 ft. Scattered showers.
Sun..SW winds 5 kt. Waves less than 1 ft. Scattered showers.
Sun night..NW winds around 5 kt. Waves 1 ft. Scattered showers.
Mon..NW winds 5 to 10 kt. Waves 1 ft.
Mon night..W winds 5 kt. Waves less than 1 ft.
Tue..SW winds around 5 kt. Waves 1 ft.
Wed..NW winds around 5 kt. Waves 1 ft.
ANZ500 1053 Am Edt Sat Apr 20 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will traverse the waters through the weekend. High pressure will build south of the waters early next week. A frontal boundary will near the waters toward midweek, lingering nearby through the end of the workweek.


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 201427
afdlwx
area forecast discussion
national weather service baltimore md washington dc
1027 am edt Sat apr 20 2019

Synopsis
Low pressure will drift over the area this weekend. High
pressure will briefly return early next week, then a cold front
will approach from the north during the middle of the week.

Near term through tonight
Surface low pressure resides over west virginia this morning as
a frontal boundary bisects our cwa. Southerly flow continues
across the area under a mix of clouds and Sun thanks to
plentiful mid-high level clouds. Temperatures are in the low to
middle 60s with dewpoints not far off, resulting in a touch of
humidity across the region. Given the available moisture in
place, limited instability within the boundary layer, we have
seen isolated to scattered shower activity across the northern
tier of the CWA this morning. This activity is currently
trending downward, and will continue to do so over the next
several hours, with much of the area remaining dry through the
bulk of the afternoon. The 12z iad sounding sampled a sizeable
dry layer between ~400-700mb, which is acting to suppress any
vertical growth of the aforementioned showers. Expect highs
this afternoon to top out in the upper 60s to lower 70s.

The primary upper trough to our west will inch closer late this
afternoon and evening, helping trigger shower development across
portions of the potomac virginia highlands, central blue ridge,
and the central foothills. Much of the shower activity will
remain west of the blue ridge into this evening, and any
accumulation will be held to a tenth of an inch or less. Skies
will be mostly cloudy overnight, with lows falling into middle
40s to near 50 degrees in the cities.

Short term Sunday through Monday night
Surface low pressure will lift northeastward as upper low slowly
moves overhead. Low 1000-500 mb thicknesses and 850 hpa temps
dropping to near 0 c are quite low for this time of year, and
are indicative of instability under the upper low. Scattered
showers seem likely Sunday as a result, and can't rule out a
little graupel either given the low freezing levels.

The upper low will finally push eastward offshore early next
week as high pressure builds from the ohio valley to just south
of the mid-atlantic. This should result in dry weather and
warming temperatures, although a few showers are still possible
Monday mainly east of i-95.

Long term Tuesday through Friday
High pressure over the southeastern united states will be in
control of the weather on Tuesday as a weak low pressure system
moves eastward through the great lakes, its attendant cold front
moving into the ohio valley. This will lead to dry and warm
conditions with highs likely reaching the upper 70s to low 80s.

The low will then pass eastward across the northeastern us on
Wednesday, with the cold front moving near the region. Thus some
showers thunderstorms become possible on Wednesday. It should
still be quite warm with highs once again in the upper 70s to
low 80s.

The front will then likely stall out near the region on Thursday
before a disturbance moves along it on Friday. This will keep
chances for showers thunderstorms in the forecast through the
end of the week. Temperatures will be dependent on the frontal
boundary location, but will show 70s for now.

Aviation 14z Saturday through Wednesday
Vfr conditions returning to the terminals today under southerly
flow gusting upwards of 20 knots through this afternoon. An
upper trough will swing overhead tonight and into Sunday,
allowing for the potential of vcsh into Sunday afternoon, but
predominateVFR is expected. Winds will turn westerly on Sunday,
coming in around 10 knots or less.

Vfr expected Monday in NW flow around 10 kts.VFR continues
Tuesday with high pressure. Chances for showers thunderstorms
will increase Wednesday but should still remain predominantly
vfr.

Marine
Gusty southerly flow today will deliver SCA conditions over the
waters. Winds will diminish this evening as light winds take
reign through Monday.

Sub-sca conditions likely Tuesday with high pressure. There is
potential for some SCA gusts Tuesday night and Wednesday as a
frontal system approaches.

Tides coastal flooding
As anomalies continue to gradually increase on sse flow, minor
flooding is occurring as several sites this morning. Additional
minor flooding is anticipated over the next couple of cycles,
before a gradual decrease in anomalies commences. Minor flooding
will remain possible through Sunday.

Lwx watches warnings advisories
Dc... Coastal flood advisory until 1 pm edt this afternoon for
dcz001.

Md... Coastal flood advisory until 2 pm edt this afternoon for
mdz508.

Coastal flood warning until 11 am edt this morning for mdz014.

Coastal flood advisory until 11 am edt this morning for mdz011.

Va... Coastal flood advisory until 1 pm edt this afternoon for
vaz054.

Wv... None.

Marine... Small craft advisory until 8 pm edt this evening for
anz530>533-535-536-538>542.

Small craft advisory until midnight edt tonight for anz534-537-
543.

Synopsis... Dhof
near term... Bkf dhof
short term... Dhof
long term... Mm
aviation... Mm bkf dhof
marine... Mm bkf dhof
tides coastal flooding... Dhof bkf


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 66 mi49 min S 11 G 12 68°F 63°F1004 hPa
BLTM2 - 8574680 - Baltimore, MD 69 mi49 min SW 8 G 16 68°F 59°F1003.6 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 72 mi49 min S 16 G 21 67°F 1003.8 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD7 mi26 minSSE 15 G 2310.00 miA Few Clouds71°F50°F47%1002.1 hPa
Eastern WV Regional Airport/Shepherd Field, WV18 mi26 minS 14 G 2410.00 miFair68°F48°F51%1001.2 hPa

Wind History from HGR (wind in knots)
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1 day agoS7S12SE9S12SE16
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2 days agoE5E8NE7E7E8E7E5E7E5E4E5E4E3NE3CalmE4E3CalmE7CalmSE3SE4S4S8

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Sat -- 04:21 AM EDT     0.01 feet Low Tide
Sat -- 06:25 AM EDT     Sunrise
Sat -- 07:26 AM EDT     Moonset
Sat -- 10:01 AM EDT     3.80 feet High Tide
Sat -- 05:03 PM EDT     -0.15 feet Low Tide
Sat -- 07:50 PM EDT     Sunset
Sat -- 09:21 PM EDT     Moonrise
Sat -- 10:35 PM EDT     3.35 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.31.60.90.400.10.81.92.93.63.83.52.92.11.40.70.2-0.20.1122.83.33.3

Tide / Current Tables for Chain Bridge, one mile below, D.C.
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Chain Bridge
Click for Map
Sat -- 04:16 AM EDT     0.01 feet Low Tide
Sat -- 06:25 AM EDT     Sunrise
Sat -- 07:26 AM EDT     Moonset
Sat -- 09:56 AM EDT     3.80 feet High Tide
Sat -- 04:58 PM EDT     -0.15 feet Low Tide
Sat -- 07:50 PM EDT     Sunset
Sat -- 09:21 PM EDT     Moonrise
Sat -- 10:30 PM EDT     3.35 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.21.50.90.400.20.9233.63.83.52.82.11.30.70.1-0.20.212.12.93.33.3

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 (12,3,4,5)
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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.