Monday, December11, 2017 L-36.com


Marine Weather and Tides
Broadlands, VA

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 7:18AMSunset 4:49PM Monday December 11, 2017 12:52 AM EST (05:52 UTC) Moonrise 12:47AMMoonset 1:22PM Illumination 47% Phase: Third Quarter Moon; Moon at 22 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
    EDIT      (on/off)   Help
ANZ535 Tidal Potomac From Key Bridge To Indian Head- 1231 Am Est Mon Dec 11 2017
.small craft advisory in effect from Tuesday morning through Tuesday afternoon...
Overnight..SW winds 5 kt. Waves less than 1 ft.
Mon..S winds around 5 kt. Waves 1 ft.
Mon night..S winds 5 kt. Waves less than 1 ft.
Tue..W winds 10 to 15 kt. Gusts up to 25 kt. Waves 1 ft.
Tue night..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Wed..W winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Wed night..W winds 5 to 10 kt. Waves 1 ft.
Thu..SW winds around 5 kt. Waves 1 ft.
Fri..W winds around 5 kt. Waves 1 ft.
ANZ500 1231 Am Est Mon Dec 11 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will build toward the waters through Monday. A frontal system will cross Monday night into Tuesday. Another low pressure system will move through the area Thursday. Small craft advisories may be required Monday night, and gale warnings are likely Tuesday into Wednesday.

7 Day Forecast for Marine Location Near Broadlands, VA
   Hourly   EDIT   Help
location: 39.02, -77.52     debug


Area Discussion for - Baltimore, MD/Washington
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxus61 klwx 110213
afdlwx
area forecast discussion
national weather service baltimore md washington dc
913 pm est Sun dec 10 2017

Synopsis
Weak high pressure will slide by south of the area through
Monday. A low pressure system will cross the lower great lakes
on Tuesday, bringing a cold front through the region. High
pressure will build overhead Wednesday with another low
pressure area approaching from the west on Thursday.

Near term until 7 am Monday morning
A weak shortwave will pass just to our north tonight bringing
an increase in clouds, but not much precipitation with it. The
latest guidance even leaves the favored upslope areas dry, but
the pattern would suggest that at least some flurries likely.

Have lowered pops further in the chance slight chance range,
and eliminated any mention of snow accumulations.

In term of temperatures, the advancing cloud shield, associated
with this wave, will reduce the extent of radiational cooling.

Thus, not much of a city-suburb spread. However, would expect
some advective cooling by dawn. As a result, guidance
temperatures not looking too bad. We'll be below freezing
areawide (in many cases, we're almost there). Favored a multi-
model mesoscale ensemble for low temps.

Short term 7 am Monday morning through Tuesday night
The shortwave will exit to our east Monday morning, with
clearing skies in its wake. Weak high pressure will move in from
the west, keeping winds light, and bringing mostly sunny skies.

This ridge will quickly move through our area, turning winds out
of the south by Monday afternoon. This will allow temperatures
to moderate a bit, topping out in the low to mid 40s. High
clouds will start to stream overhead during the afternoon hours
ahead of the next approaching shortwave over the lower great
lakes.

A stronger shortwave (compared to tonight) will near our area
late Monday night in to Tuesday morning. The associated surface
low pressure will pass to our north, dragging a cold front
through the area during the day on Tuesday. Dynamics appear
somewhat favorable with strong mid-level vorticity advection
and an upper jet nearby. Add to that low-level isentropic
upglide looks possible. Model guidance continues to keep the
bulk of the moisture north of the mason dixon line, with
upslope snow looking very likely Tuesday morning.

Temperature profiles hint at the possibility of light mixed
wintry precipitation along the northern portions of our cwa,
particularly near the md pa border. That being said, most of
the moisture and lift will remain to the north, so do not expect
much in the way of accumulation. The best chance for
accumulating snowfall will be along and west of the allegheny
front through early Tuesday afternoon, where advisory criteria
snow looks possible.

On the heels of this shortwave is another stronger mid-level
trough which will help push a cold front through the region,
bringing strong cold air advection in its wake and strong gusty
northwesterly winds. Wind direction will be favorable for
continued upslope snow and snow squall potential. Temperatures
at the surface and aloft do not seem too supportive of snow
squalls making much impact east of the mountains. The
combination of strong gusty winds and the cold air filtering in,
wind chills may drop below zero over the western ridges of
allegheny front. Tuesday night, temperatures will fall in to the
teens across our western zones, lower 20s elsewhere, and the middle
20s in the metro areas.

Long term Wednesday through Sunday
A highly amplified upper level flow pattern with east coast
troughing will result in a wintry pattern through Friday. Wednesday
will be blustery and cold, with strong winds possible as low
pressure pulls away from maine. High temperatures may fail to crack
the freezing mark across a large part of the area. With a slightly
faster exit to the upper trough, flurries are looking less likely on
Wednesday. Weak surface ridging will relax the winds by Wednesday
night, but lows will be in the teens and 20s.

There's some model spread in timing on the next clipper system which
will arrive sometime between late Wednesday night and Thursday
evening. While the best chance for snow will be along the upslope
areas, it's not out of the question some light snow could spread
east of the mountains as well, particularly near the pennsylvania
border. The next, sharper shortwave trough will arrive on Friday,
prolonging chances for upslope snow. Instability through the snow
growth zone could allow snow showers to move east of the mountains
as well, although surface temperatures will likely rise above
freezing at lower elevations.

The upper level pattern will break down to more progressive flow
next weekend. Surface high pressure will arrive on Saturday and
temperatures will rise closer to normal. There's still a large
amount of uncertainty regarding the next frontal system which may
arrive late in the weekend.

Aviation 02z Monday through Friday
Vfr conditions are expected at all the terminals through Monday
as weak high pressure traverses the area. Clouds will be mostly
mid deck, with sct-bkn stratocumulus around 040-050 by dawn.

These clouds will dissipate after sunrise.

A clipper system will pass to the north Monday night in to
Tuesday, bringing the possibility of brief flight restrictions
along and to the north of mrb bwi mtn. Behind a cold frontal
passage on Tuesday, gusty northwesterly winds will overtake the
terminals in to Tuesday afternoon and Tuesday night, gusting 25
to 30 knots.

OverallVFR conditions are expected Wednesday through
Friday. W NW winds could gust over 30 kt on Wednesday. There are
a couple disturbances which could bring snow showers Thursday
and Friday, but impacts are uncertain at this time.

Marine
Winds greatly diminished near sunset. However, a 25-kt low-
level (near 2000 ft) jet ahead of a shortwave traversing the
waters at this time. Since water temperatures are warmer than
air temps, momentum transfer has been favorable. Multiple
reports of 20 kt gusts noted from meso sites. Consequently,
reissued a small craft advisory for most of the waters through
daybreak. Left out the upper tidal potomac, patuxent, baltimore
harbor, north of pooles island, and chester.

Weak high pressure moving through on Monday will bring a return
of light winds (less than 10 kt). Ahead of an approaching cold
front Monday night and Tuesday, winds may reach SCA level, with
sca likely behind the front Tuesday afternoon and night with
strong gusty northwesterly flow. Gale conditions look possible
behind the front, and through Tuesday night.

Strong winds will continue into Wednesday behind departing low
pressure. Small craft advisory conditions are likely, and gales are
possible early in the day. High pressure will bring lighter winds by
late Wednesday night. Low pressure will cross near the area on
Thursday, but winds may not increase appreciably at the surface
until a second disturbance moves through on Friday.

Lwx watches warnings advisories
Dc... None.

Md... None.

Va... None.

Wv... None.

Marine... Small craft advisory until 7 am est Monday for anz531>534-536-
537-540-541-543.

Synopsis... Bkf
near term... Hts
short term... Bkf
long term... Ads
aviation... Hts bkf ads
marine... Hts bkf ads


Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map
Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 28 mi52 min S 5.1 G 6 38°F 45°F1018.2 hPa
BSLM2 - Chesapeake Bay, MD 46 mi82 min S 4.1 35°F 1018 hPa27°F
BLTM2 - 8574680 - Baltimore, MD 53 mi52 min WSW 2.9 G 5.1 36°F 51°F1017.3 hPa (-0.0)

Wind History for Washington, DC
(wind in knots)    EDIT      (on/off)   Help
1
AM
-12
PM
3
AM
-12
PM
-12
PM
-12
PM
7
AM
8
AM
9
AM
10
AM
-12
PM
12
PM
1
PM
2
PM
-12
PM
-12
PM
-12
PM
6
PM
-12
PM
8
PM
-12
PM
-12
PM
11
PM
12
AM
Last
24hr
SW3
G6
S4
W5
W4
SW5
G8
SW2
G5
W7
W6
G11
W7
G12
SW3
S7
G10
S6
G10
S4
1 day
ago
S4
G7
S4
W2
SW2
W2
--
N2
N4
G8
NE7
G10
N6
G11
N2
G5
N4
G8
NW3
G7
NW4
G9
NW2
G7
W5
NW5
NW5
G8
W4
SW5
W3
2 days
ago
N3
G7
N4
G7
NE1
N4
NW4
G7
SW1
W3
NW3
S2
SW2
SW3
S3
S8
S4
G7
S5
S4
G7
S2
S4
S4

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Leesburg / Godfrey, VA5 mi77 minN 010.00 miOvercast34°F30°F87%1017.3 hPa
Washington/Dulles International Airport, DC, VA6 mi60 minS 310.00 miOvercast34°F26°F73%1017.5 hPa
Gaithersburg - Montgomery County Airport, MD21 mi56 minS 410.00 miOvercast35°F23°F61%1020.2 hPa
Manassas, Manassas Regional Airport/Harry P. Davis Field, VA21 mi56 minS 310.00 miOvercast34°F26°F73%1019 hPa

Wind History from JYO (wind in knots)
2
AM
3
AM
4
AM
5
AM
6
AM
7
AM
8
AM
9
AM
10
AM
11
AM
12
PM
1
PM
2
PM
3
PM
4
PM
5
PM
6
PM
7
PM
8
PM
9
PM
10
PM
11
PM
12
AM
1
AM
Last 24hrCalmW5NW5W5NW18
G22
NW11
G22
NW8NW14W12
G16
W10
G17
W9
G17
W9
G15
W12
G20
W10
G17
W10
G19
W5W3CalmCalmCalmCalmCalmCalmS3
1 day agoCalmCalmCalmCalmCalmCalmCalmCalmNE6NE4NE3NE3N6NE5CalmCalmCalmCalmCalmCalmCalmCalmSW3SW5
2 days agoNW5NW11NW7N4N5N4NE3CalmN4CalmCalmCalmCalmCalmCalmCalmE3E3E4CalmCalmCalmCalmCalm

Tide / Current Tables for Chain Bridge, Washington, D.C.
   EDIT   RT Ports Option   Weekend mode (on/off)   (on/off)   Help   One Week of Data
Chain Bridge
Click for Map
Mon -- 12:45 AM EST     Moonrise
Mon -- 02:43 AM EST     2.73 feet High Tide
Mon -- 07:17 AM EST     Sunrise
Mon -- 09:28 AM EST     -0.24 feet Low Tide
Mon -- 01:20 PM EST     Moonset
Mon -- 03:18 PM EST     2.76 feet High Tide
Mon -- 04:46 PM EST     Sunset
Mon -- 10:00 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
1.62.32.62.72.41.91.30.70.2-0.2-0.20.41.21.92.52.72.72.21.71.10.50.1-0.20.1

Tide / Current Tables for Chain Bridge, D.C.
   EDIT      (on/off)   Help   One Week of Data
Chain Bridge
Click for Map
Mon -- 12:45 AM EST     Moonrise
Mon -- 02:39 AM EST     2.75 feet High Tide
Mon -- 07:17 AM EST     Sunrise
Mon -- 09:26 AM EST     -0.20 feet Low Tide
Mon -- 01:20 PM EST     Moonset
Mon -- 03:14 PM EST     2.76 feet High Tide
Mon -- 04:46 PM EST     Sunset
Mon -- 09:57 PM EST     -0.12 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.72.32.72.72.41.81.20.70.2-0.2-0.10.41.222.52.72.62.21.610.50.1-0.10.2

Weather Map and Satellite Images
       (on/off)   Help
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 (0,6,7,8)
      (on/off)   Help

Ground Weather Radar Station Sterling, VA
   (on/off)   Help
weather_mapweather_map weather_map

Ad by Google

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.