Wednesday, December13, 2017 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 7:20AMSunset 4:48PM Wednesday December 13, 2017 5:55 AM EST (10:55 UTC) Moonrise 2:47AMMoonset 2:21PM Illumination 25% Phase: Waning Crescent; Moon at 25 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- 331 Am Est Wed Dec 13 2017
.gale warning in effect until 6 am est early this morning...
.small craft advisory in effect through this afternoon...
.small craft advisory in effect from Thursday morning through Thursday afternoon...
Rest of the overnight..W winds 20 kt with gusts to 35 kt. Waves 2 ft.
Today..W winds 15 to 20 kt with gusts to 30 kt. Waves 2 ft.
Tonight..SW winds 5 to 10 kt. Waves 1 ft. A chance of snow. Vsby 1 to 3 nm.
Thu..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Thu night..N winds 5 to 10 kt. Waves 1 ft or less.
Fri..S winds around 5 kt. Waves flat.
Fri night..W winds 5 to 10 kt. Waves 1 ft or less.
Sat..N winds 5 to 10 kt. Waves 1 ft.
Sun..SW winds 5 to 10 kt. Waves 1 ft. A chance of showers.
ANZ500 331 Am Est Wed Dec 13 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will build overhead through this afternoon. Weak low pressure will pass through the waters late tonight through early Thursday before high pressure returns for Thursday night. Low pressure will develop as it moves up the coast Friday and high pressure will return for Saturday. A small craft advisory may be needed for portions of the waters Thursday night...and again Friday night through Saturday.

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 130850
afdlwx
area forecast discussion
national weather service baltimore md washington dc
350 am est Wed dec 13 2017

Synopsis
Weak high pressure will build overhead today. An alberta
clipper will pass nearby tonight through early Thursday.

Developing low pressure will pass off the east coast late Friday
and high pressure will return for Saturday. Low pressure may
impact the area early next week.

Near term through today
Strong northwest flow continues this morning on the backside of
the departing low pressure system along the coast of maine.

Gusts up to 25-35 mph will likely continue through the first
half of the day before abating during the afternoon hours as
weak ridging builds in. Lingering upslope snow showers along the
allegheny front early this morning will diminish as the morning
wears on. Clouds streaming into the region in the northwest
flow will also lessen in coverage, with most locations becoming
mostly sunny for a period later this morning and into the early
afternoon before clouds increase again ahead of the next fast
moving clipper system.

Temperatures will be around 10 degrees or so below climatological
normals for the day with highs only reaching the 30s. With morning
temperatures in the single digits and teens in the higher
elevations, combined with the gusty northwest winds, wind chill
advisories remain in place through noon for wind chills near
-10f.

Short term tonight through Friday night
Fast-moving clipper low diving through the midwest today will
track eastward tonight, moving along or just north of the
mason dixon line, and be off of the nj coastline by sunrise
Thursday.

Warm air advection will begin late today and this evening, and
some light snow will spread into parts of west virginia and
western maryland during the late day and evening hours, and
spread eastward during the first half of the night. With the
warm front expected to set up just north of the pa md border,
much of the precipitation should remain across pa, but some
light snow is possible as far south as the metros during the
late evening and first half of tonight. As the surface low
tracks eastward, the surface cold front will move across the
region from west to east, bringing a return to
west northwesterly flow by Thursday morning. Another period of
upslope snow is likely along and west of the allegheny front
between midnight and sunrise Thursday. Forecast nam12 froude
numbers indicate relatively terrain-blocked low level flow until
Thursday morning, which would focus much of the precip west of
the allegheny front. With the combination of light snow from the
warm air advection as well as the upslope, have issued winter
weather advisories for 2-4" of snow for the western portions of
grant, mineral, and allegheny counties.

The low will pull rapidly away during the day Thursday, with
upslope snow showers diminishing. Gusty northwest winds to 25
mph or so are expected, with highs in the 30s 40s. High pressure
will build in for Thursday night.

Another fast-moving shortwave trough will move towards the
region Friday, with a surface low tracking through the great
lakes, and a secondary low developing offshore. This will bring
the chance of a few additional snow showers. Temperatures remain
cold, with highs in the 30s to around 40f for Friday. Lows
mainly in the 20s.

Long term Saturday through Tuesday
High pressure will build overhead Saturday through Saturday
night... Bringing dry and seasonably chilly conditions. The high
will move offshore Sunday and a southerly flow will allow for
milder conditions compared to recent days. However... Low
pressure and its associated cold front will approach later
Sunday before passing through Sunday night into Monday. Showers
are possible ahead of this system later Sunday into Monday.

Another upper-level disturbance may impact the area later Monday
or Tuesday... But confidence is low at this time. Seasonable
temperatures are most likely during this time.

Aviation 08z Wednesday through Sunday
PrimarilyVFR is expected for the region through Friday night.

Gusty northwest winds up to around 30 knots will continue
through the first half of today, gradually relaxing this
afternoon. Some areas of light snow are possible this evening
and tonight and brief reductions are possible, with mrb bwi mtn
having the highest probabilities of seeing snow. Afterward, dry
conditions expected Thursday and Thursday night, with another
chance of some snow showers on Friday.

Vfr conditions are expected for Saturday through midday Sunday.

A few showers are possible later Sunday into Sunday night.

Subvfr conditions are possible during this time.

Marine
Gale warning continues for all waters until 6 am this morning
for gusty northwest winds, dropping off to the lower tidal
potomac and chesapeake bay for the rest of the day, with sca
continuing for remaining waters. Winds will turn southerly
tonight, with SCA in place over the lower tidal potomac and
chesapeake bay. As a low pressure system crosses late tonight,
gusty northwest winds return on Thursday, and SCA is in effect
for all waters.

Winds will relax Thursday night into Friday with sub-sca
conditions forecast, but SCA winds possible again Friday night
behind another low pressure system.

High pressure will approach Saturday before building overhead
Saturday night. A small craft advisory may be needed for
portions of the waters Saturday.

Low pressure and its associated cold front may impact the waters
later Sunday and Sunday night.

Tides coastal flooding
Strong northwest winds have caused tidal anomalies to drop
sharply. Blowout conditions are likely through the low tide this
morning... Especially across the middle portion of the chesapeake
bay. Anomalies will increase later this afternoon through
tonight as winds turn to the southwest.

Lwx watches warnings advisories
Dc... None.

Md... Wind chill advisory until noon est today for mdz501.

Winter weather advisory from 7 pm this evening to 7 am est
Thursday for mdz501.

Va... Wind chill advisory until noon est today for vaz503-504-507-
508.

Wv... Wind chill advisory until noon est today for wvz501-503-505-
506.

Winter weather advisory from 7 pm this evening to 7 am est
Thursday for wvz501-503.

Marine... Small craft advisory from 6 pm this evening to 6 pm est
Thursday for anz530>534-537-539>541-543.

Gale warning until 6 pm est this evening for anz530>534-537-
539>541-543.

Small craft advisory from 6 am this morning to 6 pm est this
evening for anz535-536-538-542.

Small craft advisory from 8 am to 6 pm est Thursday for anz535-
536-538-542.

Gale warning until 6 am est early this morning for anz535-536-
538-542.

Synopsis... Bjl
near term... Mm
short term... Mm
long term... Bjl
aviation... Bjl mm
marine... Bjl mm
tides coastal flooding... Bjl


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 44 mi44 min WNW 14 G 21 24°F 42°F1009.5 hPa
BLTM2 - 8574680 - Baltimore, MD 45 mi38 min NNW 11 G 17 22°F 48°F1007.3 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 49 mi38 min W 22 G 25 23°F 1007.3 hPa
FSNM2 49 mi86 min W 23 G 30 22°F 1006.2 hPa

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
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S6
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G15
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G17
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W1
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W5
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W1

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Frederick Municipal Airport, MD2 mi71 minW 1610.00 miFair21°F0°F38%1009.1 hPa
Gaithersburg - Montgomery County Airport, MD22 mi60 minW 12 G 2310.00 miMostly Cloudy19°F3°F49%1011 hPa

Wind History from FDK (wind in knots)
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Last 24hrCalmCalmSW3SW3SW6W12
G20
W12
G20
NW16
G33
NW14
G22
NW10
G15
NW15NW15
G25
NW17
G30
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--W14
G23
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G22
NW15
G21
W15
G20
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G28
W11
G26
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G21
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1 day agoSW3CalmSW3S3W8SW7S8W7S3SW4CalmCalmCalmCalmS4S4SE6CalmSE3S4S3S4S3SW4
2 days agoW7NW4NW7
G14
W7NW12W7W7
G15
W10
G14
W11
G18
W11
G18
W6W5CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmS3

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
Click for Map
Wed -- 02:45 AM EST     Moonrise
Wed -- 04:40 AM EST     2.62 feet High Tide
Wed -- 07:18 AM EST     Sunrise
Wed -- 11:12 AM EST     -0.16 feet Low Tide
Wed -- 02:21 PM EST     Moonset
Wed -- 04:46 PM EST     Sunset
Wed -- 05:07 PM EST     2.84 feet High Tide
Wed -- 11:54 PM EST     -0.15 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.20.81.52.12.52.62.31.71.10.60.1-0.2-00.61.42.12.62.82.72.21.610.50.1

Tide / Current Tables for Chain Bridge, Washington, D.C.
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Chain Bridge
Click for Map
Wed -- 02:45 AM EST     Moonrise
Wed -- 04:43 AM EST     2.63 feet High Tide
Wed -- 07:18 AM EST     Sunrise
Wed -- 11:14 AM EST     -0.21 feet Low Tide
Wed -- 02:21 PM EST     Moonset
Wed -- 04:46 PM EST     Sunset
Wed -- 05:10 PM EST     2.86 feet High Tide
Wed -- 11:55 PM EST     -0.20 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.10.81.52.12.52.62.31.71.10.60.1-0.2-0.10.51.42.12.62.92.72.21.61.10.50

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 (5,6,7,8)
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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.