Wednesday, February21, 2018 L-36.com


Marine Weather and Tides
Frederick, MD

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
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 6:51AMSunset 5:55PM Wednesday February 21, 2018 7:43 PM EST (00:43 UTC) Moonrise 10:12AMMoonset 11:54PM Illumination 42% Phase: First Quarter Moon; Moon at 7 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- 713 Pm Est Wed Feb 21 2018
.small craft advisory in effect from midnight est tonight through Thursday afternoon...
Tonight..SW winds 10 kt...becoming N after midnight. Gusts up to 20 kt. Waves 1 ft. A chance of showers with a slight chance of tstms this evening, then a chance of rain with areas of drizzle after midnight. Patchy fog. Vsby 1 to 3 nm.
Thu..NE winds 15 kt with gusts to 20 kt. Waves 1 ft. Periods of rain with areas of drizzle. Patchy fog. Vsby 1 to 3 nm.
Thu night..NE winds 10 to 15 kt. Waves 1 ft. Rain likely with areas of drizzle. Patchy fog. Vsby 1 to 3 nm.
Fri..E winds 5 to 10 kt. Waves 1 ft. Rain likely with areas of drizzle.
Fri night..S winds 5 kt. Waves less than 1 ft. A chance of rain with areas of drizzle.
Sat..NE winds around 5 kt. Waves 1 ft. A chance of showers.
Sat night..SE winds 5 kt. Waves less than 1 ft. Showers likely.
Sun..NW winds 5 to 10 kt. Waves 1 ft. Showers through the day, then a chance of showers through the night.
Mon..NW winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 713 Pm Est Wed Feb 21 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front will pass through the waters later tonight into Thursday. It will remain stalled to the south through the end of the week before gradually returning north as a warm front during the weekend. A cold front will push east across the area on Sunday.

7 Day Forecast for Marine Location Near Frederick, MD
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location: 39.43, -77.41     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 212008
afdlwx
area forecast discussion
national weather service baltimore md washington dc
308 pm est Wed feb 21 2018

Synopsis
A cold front will pass through tonight into Thursday before
stalling out to our south Thursday night. The boundary may
return north as a warm front Saturday before a stronger cold
front passes through from the west on Sunday. High pressure will
return for early next week.

Near term through Thursday
Current surface analysis depicts low pressure over quebec. A
cold front extends southwest from the low across northern new
england, western new york, western pennsylvania, west virginia,
kentucky, central tennessee, northwestern mississippi and
northern louisiana, connecting to another wave of low pressure
developing over texas. Canadian high pressure is sitting behind
the front over iowa while bermuda high pressure is located over
the western atlantic. Aloft, an incredibly strong ridge is
centered just off the carolina coast, while a trough dominates
the western us, with a large are of southwesterly flow across
most of the nation between the two systems.

As of 2 pm, record daily high temperatures have been set all
across the region, and depending on cloud cover over the next
few hours, all-time monthly record highs for february may still
be reached. Depending on how temperatures behave this evening,
some record high minimum temperatures may also be tied or
broken. See climate section below for details.

However, the end is quickly approaching. The front will cross
most of the CWA by midnight or so and should clear the remaining
portions of the CWA early in the morning. Ahead of this front,
some showers have developed, and we may even have a rumble a
thunder this evening as some weak CAPE has formed thanks to the
record warmth plus unusually high dew points (60s in many
areas). Once the front passes, temps will be almost on a
continuous decline for over 24 hours as the canadian high
pressure over the midwest moves northeast towards new england
and pushes cold air southward on the east side of the mountains
on a raw north to northeast flow. Combined with a wave of low
pressure riding northeast along the stalling frontal boundary,
and we will have a day which feels brutal compared to today,
even though temps will actually be close to normal. While
Thursday will be cooler with lots of low clouds, mist and
drizzle, most of the significant rainfall still appears likely
to be further north into the cold air thanks to mid-level fgen
staying over pa and wv, so we are not expecting a lot of rain
across our region. By this time tomorrow, temperatures will be
more than 30 degrees colder than at present, with some places
perhaps nearly 40 degrees lower.

Short term Thursday night through Friday night
Wave of low pressure passes northeast along the stalled front on
Thursday night, with rain diminishing, but drizzle will linger.

We still have a small threat of freezing rain later at night
across northern portions of the region, particularly western
maryland, depending on how much cold air can build south across
the region.

Another wave of low pressure will develop in texas and move
northeast along the front early Friday, with another round of
rain expected in the morning. By afternoon, this wave should be
north of the region, and it will just be cloudy and drizzly
again. Temperatures should warm a bit, perhaps reaching the low
50s late.

Warm front aloft pushes north Friday night, but the surface
front will be stuck to our south thanks to the high to the
northeast providing a low level cold air wedge, so it will
remain relatively cool and drizzly. However, temperatures should
be steady or slowly rising as the cold air gradually erodes.

Long term Saturday through Wednesday
A frontal boundary will be stalled over our area on Saturday
separating a colder air mass from warm air. The boundary will
lift as a warm front Saturday night while a cold front moves
through on Sunday. These will allow for rain showers over our
area from Saturday into Sunday. Conditions should be drying out
Sunday night and remain dry through Wednesday as high pressure
builds in from the west and then settles overhead.

Temperatures will be above normal Saturday and Sunday and then
gradually become more normal by mid-week.

Aviation 20z Wednesday through Monday
Vfr and gusty southwest winds at all sites through the rest of
today. As a cold front approaches and crosses the region this
evening and tonight, rain showers and even an isolated
thunderstorm are possible, with best odds being at mrb, then
moving towards dca bwi iad later in the evening. Winds will
turn northerly behind the front, and low ceilings with MVFR
conditions are forecast develop by early Thursday morning.

MVFR ifr conditions are then likely in low clouds, areas of
rain, and drizzle Thursday, Thursday night, and potentially
lasting into Friday.

Sub-vfr conditions possible Saturday into Sunday with a frontal
boundary affecting our area.VFR conditions should return on
Monday with high pressure building over us.

Marine
Southerly winds with SCA conditions across the waters this
afternoon. With warm air temperatures expected over
considerably cooler waters, the strongest gusts will likely be
observed along the shorelines. As a cold front crosses the
region tonight, winds will turn northerly behind the front, and
now look more likely to reach SCA criteria, so have raised one
for the bay and adjacent waters (except the potomac) for after
midnight. Northeast flow looks to remain elevated on Thursday,
so maintain SCA thru the day. It may need additional extension
into the evening, but at this point am not confident about this
so have cut it off at the end of the day. As the front starts a
gradual retreat back to the north on Friday, winds should
diminish below sca.

Winds are expected to remain below SCA criteria on Saturday.

Sunday winds will increase and come close to criteria, so it
should be monitored in case a SCA is needed. Winds will decrease
on Sunday night and remain below criteria into Monday.

Climate
The all-time february highest minimums are:
61 at dca washington (2 17 1891)
58 at bwi baltimore (2 17 1891)
55 at iad dulles (2 17 1976)
- records only go back to 1960 at iad
the all-time february highest maximums are:
84 at dca washington (2 25 1930)
83 at bwi baltimore (2 25 1930)
79 at iad dulles (2 24 1985 and 2 25 2000)
- records only go back to 1960 at iad
record warm daily maximum temperatures
wed 2 21
dca 75 (1953)
bwi 74 (1930)
iad 70 (1997)
record warm daily minimum temperatures
wed 2 21
dca 51 (1954)
bwi 49 (1981)
iad 45 (1981)

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory until 6 pm est this evening for
anz530>543.

Small craft advisory from midnight tonight to 6 pm est
Thursday for anz530>534-537>543.

Synopsis... Rcm
near term... Rcm
short term... Rcm
long term... Imr
aviation... Imr rcm
marine... Imr rcm
climate... Lwx rcm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 44 mi44 min S 6 G 8 68°F 48°F1026 hPa (+1.8)
BLTM2 - 8574680 - Baltimore, MD 45 mi44 min SSW 1 G 2.9 72°F 44°F1025.1 hPa (+1.5)
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 49 mi44 min ESE 4.1 G 5.1 1025.5 hPa (+1.7)
FSNM2 49 mi44 min SSW 5.1 G 8 78°F 1025.4 hPa (+1.6)

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Frederick Municipal Airport, MD2 mi57 minN 010.00 miOvercast70°F69°F100%1026.4 hPa
Gaithersburg - Montgomery County Airport, MD22 mi48 minWSW 610.00 miOvercast76°F61°F60%1028.9 hPa

Wind History from FDK (wind in knots)
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Last 24hrS8S11
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S9S8S6S4CalmW3CalmCalmCalmCalmW4SW13
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1 day agoS4S4S3CalmCalmCalmSW5SW5SW5SW4SW4SW4SW5SW6SW6SW9SW9
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2 days agoCalmCalmCalmCalmCalmCalmCalmCalmS5S7S5SE5S5S6S6S7S6S6S6S5S6S7S7S4

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Wed -- 06:23 AM EST     -0.02 feet Low Tide
Wed -- 06:52 AM EST     Sunrise
Wed -- 10:11 AM EST     Moonrise
Wed -- 12:06 PM EST     3.06 feet High Tide
Wed -- 05:52 PM EST     Sunset
Wed -- 07:12 PM EST     0.09 feet Low Tide
Wed -- 11:52 PM EST     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.82.621.40.70.3-000.31.122.83.12.92.41.81.10.60.30.10.20.61.42.2

Tide / Current Tables for Chain Bridge, Washington, D.C.
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Chain Bridge
Click for Map
Wed -- 06:25 AM EST     -0.08 feet Low Tide
Wed -- 06:52 AM EST     Sunrise
Wed -- 10:11 AM EST     Moonrise
Wed -- 12:08 PM EST     3.08 feet High Tide
Wed -- 05:52 PM EST     Sunset
Wed -- 07:12 PM EST     0.03 feet Low Tide
Wed -- 11:52 PM EST     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.82.62.11.40.70.2-0-00.3122.83.12.92.41.81.10.60.200.10.51.32.2

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 (19,4,5,8)
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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.