Saturday, December16, 2017 L-36.com


Marine Weather and Tides
Chambersburg, PA

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 7:24AMSunset 4:48PM Saturday December 16, 2017 1:44 PM EST (18:44 UTC) Moonrise 5:42AMMoonset 4:03PM Illumination 3% Phase: Waning Crescent; Moon at 28 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- 1231 Pm Est Sat Dec 16 2017
.small craft advisory in effect until 7 pm est this evening...
This afternoon..SW winds 15 kt with gusts to 20 kt. Waves 1 ft.
Tonight..W winds 10 to 15 kt with gusts to 20 kt... Becoming E around 5 kt after midnight. Waves 1 ft or less.
Sun..SE winds around 5 kt. Waves flat.
Sun night..SW winds around 5 kt. Waves flat.
Mon..SW winds around 5 kt. Waves flat.
Mon night..SW winds 5 kt. Waves flat.
Tue..W winds 5 to 10 kt. Waves 1 ft or less.
Wed..N winds 5 to 10 kt. Waves 1 ft.
ANZ500 1231 Pm Est Sat Dec 16 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will build south of the waters through the weekend. A backdoor cold front will approach from the north Sunday, then return north as a warm front Monday.

7 Day Forecast for Marine Location Near Chambersburg , PA
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location: 39.93, -77.66     debug


Area Discussion for - State College, PA
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Fxus61 kctp 161542
afdctp
area forecast discussion
national weather service state college pa
1042 am est Sat dec 16 2017

Synopsis
Cold northwest flow and lake effect snow showers in the lee of
lake erie are expected today. High pressure and a brief
moderating trend in the temperature are expected by Sunday. A
series of cold fronts will move across the area late Sunday into
Wednesday. Windy and colder temperatures will follow.

Near term until 7 pm this evening
Snow starting to lift to the N E a bit, and only bfd is
occasionally ifr. Otherwise, Sun really busting through in the
south. Continue to expect a slow recession of the snow to the
north and it should be confined to the northern 4 counties by
this evening before dying off. Nudged temps up a little for
current trends, ESP in the sc where little no snow is on the
ground. No plans to change the headline in the NW as snow is
still falling, and timing for the heavier stuff to taper off
around 21z still look good. While s-- will linger into the
night, no reall accums are expected after sunset.

Prev...

upper trof moving off of the eastern seaboard this morning with
channeled northwest flow organizing lake effect snow bands over
the eastern lakes and depositing over my northwest mountains.

Cams indicate incoming banding will extend into the central and
north central mountains this morning with light coatings
expected there. Going advisories in good shape with several
more inches of accumulation expected through this afternoon.

Lake effect snow showers will diminish by late this afternoon as
heights continue to rise and inversion heights lower. It will
still be colder than normal with highs ranging from the upper
20s northwest to around 40 over the south.

Short term 7 pm this evening through 6 pm Sunday
High pressure centered over eastern ontario and southern quebec
and over the southeastern coastal states tonight will bring
fair and cold conditions. Upper ridging will be tempered on
Sunday by an embedded disturbance in the return moisture flow
west of the sfc ridge axis, which may bring scattered rain and
snow showers to the southern third of central pa Sunday
afternoon. Amounts will be barely measurable, and with marginal
sfc temperatures am not expecting any accumulations... Just
melting at this time. Highs will range from the mid 30s north to
the lower 40s south on Sunday.

Long term Sunday night through Friday
This coming week will see the long-wave upper level trough that
has been dominating out weather shift east as a deep trough digs
over the western u.S. Lake enhanced snow showers should be
ending by Saturday night with the surface high pressure ridge
moving off the coast and the winds becoming move west to
southwesterly.

The western trough kicks a strong shortwave out across the
plains Sunday into Monday. The associated low center will move
northeast across the great lakes staying to our north and west.

This system will bring in warmer air in southwest flow ahead of
it. However, we may be cold air dammed near the surface so the
+1 to -2c air at 850 hpa may not translate to a warm boundary
layer. The warm advection should bring snow and snow to rain in
the south but QPF amounts are light. Will have to watch for
potential for some ice also Sunday night.

We look to move into a fast moving pattern of weak shortwaves
and chances for precipitation (mainly over the northern
mountains) through the week. As a northern stream wave zips by
to our north by Monday night, it should drag cold air back into
the region Tuesday into Wednesday. The northwest flow triggers
snow in relatively high pops in NW pa due to les. This cold
surge should be relatively fleeting and high pressure and a
potential surge of relatively warmer air follows Thursday.

The warm advection and approaching cold front will likely
produce increased potential for snow in NW Thursday into Friday.

Farther south any precipitation would likely be mixed or rain.

A strong frontal boundary will likely push another surge of
cold air into the region Friday into Saturday as the eastern
long wave trough tries to re-establish itself.

Aviation 16z Saturday through Wednesday
All trends seen earlier are proceeding as expected. Wind is
picking up and some recession lift to the thicker clouds is
forecast for the daylight hours.

Prev...

the snow bands continue to weaken though bands will continue
through the NW and central mountains. Most of the snow is
producingVFR to MVFR restrictions, however periods of heavier
bands will bring ifr vsbys to bfd and jst arctic fropa
overnight will shift winds to the northwest, producing a more
favorable over- lake trajectory. This will invigorate snow
showers over the western and northern mountains.

Result will be highly variable visibility conditions in the
north and west as snow showers drift in and out.

Outlook...

sat... Scattered snow showers and local restrictions NW laurels.

Sun-mon... MainlyVFR.

Tue-wed... MainlyVFR, but possible restrictions in the western
and northern mountains in snow showers.

Ctp watches warnings advisories
Winter weather advisory until 4 pm est this afternoon for
paz004-005.

Synopsis... Devoir
near term... Dangelo devoir
short term... Devoir
long term... Watson
aviation... Dangelo ceru


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BLTM2 - 8574680 - Baltimore, MD 73 mi44 min W 8 G 13 42°F 46°F1018.3 hPa (-2.5)
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 78 mi44 min SW 14 G 18 42°F 1018.5 hPa (-2.5)
WASD2 - 8594900 - Washington, DC 81 mi44 min S 11 G 15 43°F 39°F1019.3 hPa (-2.6)

Wind History for Baltimore, MD
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD16 mi51 minWSW 1110.00 miPartly Cloudy47°F21°F37%1018 hPa

Wind History from HGR (wind in knots)
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Last 24hrS6SW4S6S3S3S3W5SW7SW5W11W17W14
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1 day agoNW13
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W15NW14NW8NW7NW7NW7N7N5E3NE4NE3NE4S3SW3S5SE5SE5SE6SE5S9S8S9S8
2 days agoW15W9W6W3S3S9
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S4SE4CalmNW3CalmN3NW4CalmNW7CalmCalmCalmSW4NW14
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Tide / Current Tables for Middle Branch, Baltimore Harbor, Maryland
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Middle Branch
Click for Map
Sat -- 12:31 AM EST     0.09 feet Low Tide
Sat -- 05:15 AM EST     0.69 feet High Tide
Sat -- 05:36 AM EST     Moonrise
Sat -- 07:19 AM EST     Sunrise
Sat -- 11:30 AM EST     -0.22 feet Low Tide
Sat -- 04:00 PM EST     Moonset
Sat -- 04:44 PM EST     Sunset
Sat -- 06:18 PM EST     1.17 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.10.10.20.40.60.70.70.50.30.1-0.1-0.2-0.2-0.10.20.50.81.11.21.110.80.60.4

Tide / Current Tables for Middle Branch, Baltimore Harbor, Patapsco River, Maryland
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Middle Branch
Click for Map
Sat -- 12:31 AM EST     0.09 feet Low Tide
Sat -- 05:15 AM EST     0.69 feet High Tide
Sat -- 05:36 AM EST     Moonrise
Sat -- 07:19 AM EST     Sunrise
Sat -- 11:30 AM EST     -0.22 feet Low Tide
Sat -- 04:00 PM EST     Moonset
Sat -- 04:44 PM EST     Sunset
Sat -- 06:18 PM EST     1.17 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.10.10.20.40.60.70.70.50.30.1-0.1-0.2-0.2-0.10.20.50.81.11.21.110.80.60.4

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 State College, PA (13,3,4,5)
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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.