Monday, December11, 2017 L-36.com


Marine Weather and Tides
Rock Hall, 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 7:14AMSunset 4:45PM Monday December 11, 2017 5:39 PM EST (22:39 UTC) Moonrise 12:42AMMoonset 1:17PM Illumination 40% Phase: Third Quarter Moon; Moon at 23 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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ANZ531 Chesapeake Bay From Pooles Island To Sandy Point- 332 Pm Est Mon Dec 11 2017
.small craft advisory in effect from midnight est tonight through Tuesday afternoon...
.gale warning in effect from Tuesday afternoon through late Tuesday night...
Rest of this afternoon..SW winds 5 kt. Waves less than 1 ft.
Tonight..S winds 10 to 15 kt. Gusts up to 20 kt in the late evening and overnight. Waves 1 to 2 ft. A chance of showers, snow showers and sleet. Vsby 1 to 3 nm.
Tue..SW winds 15 kt with gusts to 20 kt... Becoming W 20 to 25 kt with gusts to 30 kt in the afternoon. Waves 2 ft...building to 4 ft in the afternoon. A chance of showers, snow showers and sleet. Vsby 1 to 3 nm.
Tue night..W winds 20 to 25 kt with gusts to 35 kt. Waves 3 ft.
Wed..W winds 20 to 25 kt with gusts to 35 kt. Waves 4 ft.
Wed night..W winds 15 to 20 kt with gusts to 25 kt...diminishing to 10 kt after midnight. Waves 1 to 2 ft. A chance of snow.
Thu..N winds 5 to 10 kt. Waves 1 ft. A chance of snow in the morning.
Fri..NW winds 5 to 10 kt. Waves 1 ft or less... Building to 2 ft after midnight. A chance of rain or snow showers through the day.
ANZ500 332 Pm Est Mon Dec 11 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will move offshore tonight. An arctic cold front will pass through late Tuesday and high pressure will return for Wednesday. Weak low pressure will pass through the waters Thursday and another weak low will pass by to the east Friday. A gale warning may be needed for portions of the waters Wednesday. A small craft advisory may be needed for portions of the waters Wednesday night and Thursday.

7 Day Forecast for Marine Location Near Rock Hall, MD
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location: 39.15, -76.35     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 112026
afdlwx
area forecast discussion
national weather service baltimore md washington dc
326 pm est Mon dec 11 2017

Synopsis
Weak high pressure will slide offshore tonight. An arctic cold
front will pass through the area Tuesday and weak high pressure
will build overhead Wednesday. Weak low pressure will pass
through Thursday and another one will pass by to the east
Friday. High pressure will return for Saturday.

Near term through Tuesday
High pressure is overhead at present but we have mid clouds
moving overhead as warm advection gets underway aloft. This will
continue tonight. We may have a brief period of clear skies
allowing temps to radiate down near or just below freezing, but
after that clouds should become abundant enough (if they aren't
abundant enough through the night) to keep temps from falling
further, and in fact they may rise through the night. A south
wind, though light, will dominate.

A few models still generate some weak warm advection precip late
tonight and early Tuesday as the warm front ahead of the
approaching system lifts north. The atmosphere is dry and most
models show no measureable precip east of the allegheny front,
however. So, have kept pops low, in the chance to slight chance
category. Given the dry profiles, frozen precip could try to
make it to the ground (sleet or snow), but with the warm actual
temps, its not impossible something melts and then tries to
refreeze at the surface if it remains cold enough overnight.

Therefore, have allowed for all p-types where temps may be below
freezing, and rain sleet snow showers elsewhere.

All that having been said, given the low probability, the most
likely outcome of tonight still looks like dry conditions with
temps, if they do fall below freezing early, rising back above
freezing later on, with no travel issues east of the allegheny
front.

On Tuesday, the warm front lifts northward east of the mountains
and we could get pretty mild ahead of the cold front. Raised our
highs a bit and they may need to come up a bit more given how
mild it got today. East of the allegheny front, precip should be
spotty and light, with any frozen transitioning to rain showers
as temps warm during the am. However, during the afternoon the
strong cold front will blast across the area, with temps likely
falling during the afternoon. With strong forcing and a little
instability, would not rule out some showers with or just
behind the front itself, so maintained some slight chance pops,
with any rain showers transitioning back to snow. Winds will
blow at least up to 30 mph with the front, and its not
impossible we touch wind advisory criteria, though at this time
its not our official forecast. Will let next shifts re- evaluate
this potential.

Along the allegheny front itself, the story will be quite
different. Upslope flow will allow snow showers to develop late
tonight and continue through the day on Tuesday. Accumulations
during the day look like a general 3-6 inches, so have issued a
winter weather advisory for the most likely locations (western
pendleton and western grant). This may be a bit conservative as
accumulations could touch advisory levels in western mineral,
western alleghany and western highland, and next shift will need
to re-evaluate. Its also possible that given the strong upslope
flow on Tuesday, we could reach warning criteria in western
pendleton and western grant, particularly our sweet spot in
bayard. Next shift will look hard at this potential as well.

Final issue which occurs mainly Tuesday night but starts late
Tuesday afternoon is the wind chill. Most of Tuesday will stay
above criteria all zones, but by late Tuesday afternoon, the
strong gusty winds plus falling temps well into the teens will
bring wind chills down into the single digits along portions of
the allegheny front, so started the advisory for wind chills
late in the afternoon in these areas.

Short term Tuesday night through Wednesday night
The cold is the main story for the short term period as a brutal
air mass moves down from canada. Winds will gust all night long
and into Wednesday morning as high pressure briefly builds into
the region. Probably stay shy of wind advisory most areas, but
it may be close. Either way, with the strong cold advection,
wind chills will fall into the single digits across the board,
and across most of the far western counties it will reach wind
chill criteria, so expanded wind chill advisory across western
zones. May need to add blue ridge zones as well.

Other story is the continued upslope snow along the allegheny
front, which will continue through the night into early
Wednesday morning before tapering off as high pressure builds.

As mentioned above, we may approach warning criteria in our
advisory zones, and advisory criteria in some of the zones
adjacent to the current advisory, so future shifts may further
expand upgrade the existing headlines.

As weak ridge of high pressure builds across Wednesday, winds
will slack off and upslope snow will end by afternoon, but cold
air mass will keep temps mostly below freezing through the day -
coldest day of the year.

Then a clipper system starts moving in Thursday night. Still
some uncertainty with this system as it croses the area, but
with the low expected to track south of at least part if not
most of the cwa, the odds of some snow is certainly significant.

Accumulations however will likely not be much. Best odds of snow
however are northern areas near pa, locations where the low is
most likely to stay south of. Lows will be in the 20s Wednesday
night.

Long term Thursday through Monday
Not as chilly Thursday with a chance for snow showers, mainly
in the west and north, as the next low pressure system arrives
from the west. The chance for snow showers linger Thursday night
and Friday, as well, due to the upper level cold air support
behind the surface storm.

A modifying area of high pressure is expected to build eastward
behind the low pressure system Friday night through Saturday
night, bringing milder temperatures and temperate southwesterly
breeze.

By Sunday, the next threat for rain or snow showers will come
with a cold front sagging southward across the region. High
temperatures, next weekend, could reach the 50s. A low pressure
system could attach to the cold front and bring added lift of
support for rain or snow showers Sunday and Monday.

Aviation 20z Monday through Saturday
Vfr expected overall through Thursday night. However, it may not
be completely so. Light precip is possible at times through the
next 24 hours, which could be mixed rain sleet snow later
tonight into Tuesday morning, and snow showers squalls later
Tuesday into Tuesday night. Any of these can reduce CIGS and vis
belowVFR. Additionally, clipper system may bring light snow to
the region late Wednesday night into Thursday, which would do
likewise. Otherwise, main story is the northwest wind later
Tuesday into early Wednesday, with 30+ knot gusts likely at
times. A few 40 knot gusts can't be ruled out either.

Vfr conditions Thursday night through Friday night. Winds
southwest at 5 to 10 knots Thursday night, becoming northwest
around 10 knots Friday and Friday night.

Marine
Quiet on the waters now but it won't stay that way. Southerly
flow ahead of approaching cold front will increase tonight, with
sca slowly spreading across the waters as we head into Tuesday.

Then strong cold front is likely to bring gales late Tuesday
into early Wednesday, and a gale warning is in effect for this
period. Gales may linger through Wednesday morning before
diminishing, but SCA may be needed through Thursday as another,
much weaker low moves across the region.

No marine hazards Thursday night through Friday night. Winds
southwest around 10 knots Thursday night, becoming northwest
around 10 knots Friday and Friday night.

Tides coastal flooding
Elevated water levels from earlier have droped some today as
the flow GOES west to northwest... But anomalies will likely
increase as a southerly flow picks up for tonight into Tuesday.

At this time... It does not appear that there will be minor
flooding but it will have to be monitored closely for sensitive
areas.

Strong northwest winds are expected later Tuesday and Tuesday
night. Tidal blowout conditions are possible Tuesday night into
Wednesday.

Lwx watches warnings advisories
Dc... None.

Md... Wind chill advisory from midnight Tuesday night to 6 am est
Wednesday for mdz501.

Va... Wind chill advisory from midnight Tuesday night to 6 am est
Wednesday for vaz504.

Wind chill advisory from 6 pm Tuesday to 6 am est Wednesday
for vaz503.

Wv... Wind chill advisory from midnight Tuesday night to 6 am est
Wednesday for wvz503-506.

Winter weather advisory from 7 am Tuesday to 7 am est
Wednesday for wvz501-505.

Wind chill advisory from 4 pm Tuesday to 6 am est Wednesday
for wvz501-505.

Marine... Small craft advisory from midnight tonight to 4 pm est Tuesday
for anz531>533-537-539>543.

Gale warning from 4 pm Tuesday to 6 am est Wednesday for
anz530>543.

Small craft advisory from noon to 4 pm est Tuesday for anz535-
536-538.

Small craft advisory from 6 am to 4 pm est Tuesday for anz530.

Small craft advisory from 9 pm this evening to 4 pm est
Tuesday for anz534.

Synopsis... Rcm
near term... Rcm
short term... Rcm
long term... Klw
aviation... Rcm klw
marine... Rcm klw
tides coastal flooding... Rcm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
TCBM2 - 8573364 - Tolchester Beach, MD 7 mi51 min SSE 1.9 G 4.1 42°F 43°F1016.1 hPa
FSNM2 10 mi57 min S 9.9 G 14 43°F 1015.1 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 11 mi51 min SSE 12 G 13 44°F 1015.6 hPa
CPVM2 11 mi51 min 44°F
APAM2 - 8575512 - Annapolis, MD 13 mi51 min 43°F 1015.2 hPa
BLTM2 - 8574680 - Baltimore, MD 15 mi51 min SSW 5.1 G 8 44°F 50°F1015.2 hPa
TPLM2 - Thomas Point, MD 18 mi39 min SSE 13 G 14 44°F 48°F
BSLM2 - Chesapeake Bay, MD 32 mi69 min SE 5.1 45°F 1016 hPa28°F
CHCM2 - 8573927 - Chesapeake City, MD 39 mi51 min ESE 1.9 G 2.9 1016.3 hPa
WASD2 - 8594900 - Washington, DC 40 mi51 min S 4.1 G 5.1 46°F 45°F1015.3 hPa
44062 - Gooses Reef, MD 41 mi39 min SSE 14 G 16 44°F 48°F1 ft1016.4 hPa (-0.5)
CA2 - 8571892 - Cambridge, MD 42 mi51 min 1017.3 hPa
DRSD1 - Delaware Reserve, DE 49 mi69 min Calm 41°F 1016 hPa25°F

Wind History for Tolchester Beach, MD
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Bay Bridge Field, MD12 mi54 minSSE 610.00 miFair41°F26°F57%1016.3 hPa
Baltimore / Martin, MD14 mi49 minSSE 710.00 miClear43°F33°F71%1016.6 hPa
Annapolis, United States Naval Academy, MD14 mi45 minS 610.00 miFair42°F28°F60%1016 hPa
Baltimore, Inner Harbor, MD16 mi45 minno data mi45°F25°F46%1015.4 hPa
Baltimore, Baltimore-Washington International Airport, MD17 mi45 minSE 510.00 miA Few Clouds42°F27°F55%1015.4 hPa
Fort Meade / Tipton, MD23 mi54 minN 010.00 miFair43°F26°F53%1016.3 hPa
Phillips Army Air Field / Aberdeen, MD24 mi1.7 hrsESE 410.00 miMostly Cloudy43°F23°F46%1016.3 hPa

Wind History from MTN (wind in knots)
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Last 24hrSW4CalmCalmCalmCalmCalmS4S3S6SE7CalmCalmCalmCalmCalmCalmCalmCalmW9SW8W5SW3CalmSE7
1 day agoW6NW4W4W3CalmSW3CalmSW3SW5W3W4SW5SW4W4CalmW6SW9SW5W10
G16
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2 days agoCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmNW3CalmNW5N7NW7N5N6N5NW3NW3NW4NW4

Tide / Current Tables for Baltimore (Chesapeake Bay), Maryland
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Baltimore (Chesapeake Bay)
Click for Map
Mon -- 12:42 AM EST     Moonrise
Mon -- 12:56 AM EST     5.15 feet High Tide
Mon -- 07:14 AM EST     Sunrise
Mon -- 07:44 AM EST     3.89 feet Low Tide
Mon -- 01:17 PM EST     Moonset
Mon -- 01:39 PM EST     4.96 feet High Tide
Mon -- 04:42 PM EST     Sunset
Mon -- 07:55 PM EST     4.12 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
5.15.25.14.94.64.44.13.93.944.34.54.84.954.84.74.54.34.24.14.24.44.6

Tide / Current Tables for Baltimore Harbor Approach, Maryland Current
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Baltimore Harbor Approach
Click for Map
Mon -- 12:42 AM EST     Moonrise
Mon -- 01:51 AM EST     -0.00 knots Slack
Mon -- 05:15 AM EST     -0.91 knots Max Ebb
Mon -- 07:14 AM EST     Sunrise
Mon -- 08:30 AM EST     0.00 knots Slack
Mon -- 11:50 AM EST     0.94 knots Max Flood
Mon -- 01:17 PM EST     Moonset
Mon -- 03:17 PM EST     -0.00 knots Slack
Mon -- 04:43 PM EST     Sunset
Mon -- 06:11 PM EST     -0.69 knots Max Ebb
Mon -- 09:17 PM EST     0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.60.3-0.1-0.4-0.8-0.9-0.9-0.6-0.20.20.60.90.90.80.50.1-0.3-0.6-0.7-0.6-0.4-0.10.20.5

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 (17,4,5,8)
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Ground Weather Radar Station Dover AFB, DE
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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.