Friday, September21, 2018 L-36.com


Marine Weather and Tides
Mercersburg, PA

Version 3.4
What's New / NOTES
9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 6:57AMSunset 7:10PM Friday September 21, 2018 12:17 PM EDT (16:17 UTC) Moonrise 4:45PMMoonset 2:24AM Illumination 89% Phase: Waxing Gibbous; Moon at 12 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- 1053 Am Edt Fri Sep 21 2018
.small craft advisory in effect through Saturday morning...
Rest of today..S winds 10 kt with gusts to 20 kt. Waves 1 ft. A slight chance of showers late this morning.
Tonight..SW winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft. Scattered showers.
Sat..N winds 5 to 10 kt. Gusts up to 20 kt until late afternoon. Waves 1 ft.
Sat night..N winds 5 kt. Waves less than 1 ft. A chance of showers.
Sun..NE winds 5 kt. Waves less than 1 ft. A chance of rain.
Sun night..NE winds 5 kt. Waves less than 1 ft. A chance of rain.
Mon..E winds 5 to 10 kt. Waves 1 ft. A chance of rain.
Tue..S winds 5 to 10 kt. Waves 1 ft. A chance of rain in the morning. A chance of showers.
ANZ500 1053 Am Edt Fri Sep 21 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will move offshore today. A cold front will approach from the great lakes this evening, cross the waters tonight into Saturday morning, and then stall south of the waters through Monday. The front will then return northward next week.


7 Day Forecast for Marine Location Near Mercersburg , PA
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location: 39.79, -77.93     debug


Area Discussion for - State College, PA
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Fxus61 kctp 211519
afdctp
area forecast discussion
national weather service state college pa
1119 am edt Fri sep 21 2018

Synopsis
A line of severe thunderstorms with damaging winds are
possible across parts of northwest and north central
pennsylvania later this evening into early tonight. A
refreshingly cooler and less humid airmass will kick-off the
fall season on Saturday with dry weather in persisting in most
areas through the weekend. Periods of rain are likely to return
Monday night into the middle of next week.

Near term through tonight
Visible satellite shows low clouds hanging tough to the east of
us-219. Mostly sunny and breezy conditions are common across the
far western alleghenies to the oh border. The satellite trends
also suggest a pre-frontal boundary likely exists from southwest
ny extending back into central oh. A few of the hires models
want to initiate convection along the boundary or near the edge
of the eroding low cloud deck this afternoon as it moves into
central pa.

The main focus remains the late-day severe damaging wind threat
associated with well-defined cold front moving eastward through
the great lakes and ohio valley. The damaging wind threat will
arise from a relatively fast-moving line of thunderstorms
(qlcs) forecast to develop by cams along ahead of the cold
front, accelerating southeastward downwind of lake erie across
northwest pa into north central pa later this evening into
early tonight.

The line should gradually weaken and lose intensity as it
continues to push southeast of i-80 99 early tonight. The threat
of severe weather should also decrease, owing to limited
instability and downsloping flow east of the alleghenies. Gusty
winds will remain possible along the front. Models show frontal
precip breaking up and progressively dissipating into the
predawn hours Saturday over the southeast 1 3 of the CWA or near
the pa turnpike.

Short term Saturday through Sunday night
Cooler, less humid air will arrive behind the front for the
upcoming weekend. The frontal boundary will stall just south of
the mason-dixon line, with fair weather persisting through
Saturday evening. Models hinting at moisture riding along the
mason dixon line Saturday night into Sunday, keeping light rain
going there for the second half of the weekend.

Long term Monday through Thursday
Model consensus supports increasing forecast confidence in a
period of rain developing north to south Monday night into
Tuesday as the wavy frontal boundary lifts back to the north
aided by return flow around 1038 mb sfc high over new brunswick.

There is also growing confidence certainty in rainfall along a
cold front crossing the appalachians around midweek.

Temperatures will rebound a bit heading into midweek ahead of
the next cold front.

Aviation 15z Friday through Tuesday
Latest satellite has low clouds over the eastern half of
pennsylvania. Periods of ifr remain possible at bfd with ifr at
aoo and MVFR elsewhere. The CIGS should slowly improve late this
morning. An approaching cold front will bring scattered showers
and thunderstorms to western areas by late this afternoon
through the first half of Friday evening. Some of the storms
could cause locally strong wind gusts and brief restrictions
with heavy rain.

Outlook
Fri... Early morning cig reductions likely. Shra tsra aftn eve.

Cfropa late.

Sat... Morning fog poss. Otherwise no sig wx.

Sun-mon...VFR after morning fog.

Tue... SubVFR conditions with showers and thunderstorms.

Ctp watches warnings advisories
None.

Synopsis... Steinbugl
near term... Steinbugl
short term... Ross devoir steinbugl
long term... Steinbugl
aviation... La corte ceru gartner


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BLTM2 - 8574680 - Baltimore, MD 80 mi30 min 70°F 78°F1022.4 hPa
WASD2 - 8594900 - Washington, DC 80 mi36 min 69°F 74°F1023 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 84 mi30 min 69°F 1022.5 hPa

Wind History for Baltimore, MD
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD12 mi25 minS 910.00 miOvercast73°F64°F76%1021.4 hPa

Wind History from HGR (wind in knots)
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Last 24hrSE5S3S8S8SE8SE6SE6SE5SE7SE8SE8S9S9S12S12S10
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1 day ago--NW8N8N8N8N6N5N4E4CalmCalmN4N4N3N3NW4NW3N3NW4N5NW3NW5Calm3
2 days agoN11
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NW9NW8NW3CalmCalmCalmCalmCalmCalmCalmCalmS3CalmCalmCalmNW53N5N7

Tide / Current Tables for Chain Bridge, D.C.
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Tide / Current Tables for Chain Bridge, Washington, D.C.
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Weather Map and Satellite Images
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wmap_A
GOES Local Image of    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for State College, PA (12,3,4,5)
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Ground Weather Radar Station Sterling, VA
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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.