Marine Weather and Tides
3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.
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.
|Sunrise 6:16AM||Sunset 7:48PM||Saturday April 21, 2018 3:23 AM EDT (07:23 UTC)||Moonrise 10:00AM||Moonset 12:00AM||Illumination 34%|
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|ANZ541 Choptank River To Cambridge Md And The Little Choptank River- 132 Am Edt Sat Apr 21 2018 |
.small craft advisory in effect until 3 am edt early this morning...
Overnight..N winds 10 kt with gusts to 20 kt. Waves 2 ft.
Sat..N winds 5 to 10 kt. Waves 1 ft.
Sat night..N winds around 5 kt. Waves flat.
Sun..SE winds around 5 kt. Waves 1 ft or less.
Sun night..S winds 5 kt. Waves flat.
Mon..SE winds 5 to 10 kt. Waves 1 ft or less.
Mon night..E winds 5 to 10 kt. Waves 1 ft.
Tue..E winds 10 to 15 kt. Waves 1 to 2 ft. Rain.
Wed..NW winds 5 to 10 kt. Waves 1 ft. Rain in the morning, then showers.
|ANZ500 132 Am Edt Sat Apr 21 2018 |
Synopsis for the tidal potomac and md portion of the chesapeake bay.. An expansive area of high pressure will build eastward from the great lakes region through the weekend, moving off the new england coast early next week. An area of low pressure over the deep south will approach the region mid week. Small craft advisories may be needed late Monday into Tuesday.
7 Day Forecast for Marine Location Near Trappe, MDHourly EDIT Help
Area Discussion for - Philadelphia/Mount Holly, PA  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxus61 kphi 210113|
area forecast discussion
national weather service mount holly nj
913 pm edt Fri apr 20 2018
High pressure builds over our area later tonight and remains in
place through the weekend, then shifts offshore on Monday. Low
pressure moves east across the gulf coast states Sunday and Monday,
then tracks up the mid-atlantic coast later Tuesday through late
Wednesday. High pressure then builds well to our west and south
later Thursday and Friday.
Near term until 6 am Saturday morning
Low pressure is positioned near the canadian maritimes this
evening while high pressure was centered over the midwest u.S.
The pressure gradient resulted in a breezy day earlier, but now
the gusts have subsided for the most part with the loss of
daytime mixing. The sustained wind speeds show a more gradual
Overall, not much change from earlier. The winds, and how fast
they diminish will be an important part of the forecast for
tonight and a key link to the frost freeze potential. The
current thinking is winds should become light late tonight with
high pressure building in from the west. Once this happens,
temperatures will drop rather quickly overnight, bottoming out
in the lower to mid 30s before daybreak (except upper 30s in the
cities and along the coast). A freeze warning was issued for
cecil county, md and for berks, western montgomery and western
chester counties in pa with lows expected to fall in the 30-32f
range and the growing season declared active. A frost advisory
was issued for northeastern md, de, the northern and western
suburbs of philadelphia and central and southern nj where (1)
the growing season is already underway, (2) temperatures are
forecast to dip into the mid 30s and (3) calm winds will provide
favorable conditions for frost formation. High clouds will
start to stream in from the west late but should not have much
of an impact on radiational cooling.
Short term 6 am Saturday morning through 6 pm Saturday
High pressure moves overhead tomorrow. A jet streak at the base of
the upper low to our northeast will be associated with mid and high
clouds over the region. There is some uncertainty regarding the
extent of the cloud cover tomorrow, but do think there will be
enough filtered sunshine or breaks in the clouds to allow for
temperatures to reach their full mixing potential during the
afternoon. Forecast highs generally range from 55-60f with slightly
cooler spots in the southern poconos and warmer spots in
philadelphia and toward southern delaware. NW winds 4-8 mph in the
morning, increasing to 8-12 mph in the afternoon.
Long term Saturday night through Friday
Summary... Turning warmer, however a coastal low looks to affect our
weather Tuesday night through Wednesday.
Synoptic overview... An upper-level trough across the northeast is
forecast to shift offshore later in the weekend. As this occurs, a
ridge slides eastward from the great lakes driving surface high
pressure over our area. However, strong energy underneath this ridge
moves across the gulf coast states over the weekend into early next
week with surface low pressure associated with it. Meanwhile,
northern stream short wave over the great lakes region is forecast
to begin phasing with the southern stream closed low over the
southeast u.S. The model spread increases during this time frame due
to the timing of the phasing and the speed of the resulting surface
low near the east coast. The surface low is forecast to basically
slide northward by the mid-atlantic coast during mid-week before
shifting to our northeast to start Thursday. An upper-level trough
looks to then settle into the east for the end of next week while
weak surface high pressure slides to our south. This trough may
eventually lead to another coastal low development with time.
For Saturday night through Monday... Surface high pressure builds
over the region as an upper-level ridge slides eastward. The surface
high though will shift offshore Monday as low pressure tracks across
the southeastern u.S. The presence of surface high pressure over the
area will result in subsidence and a lack of clouds overall with
less wind, with the airmass modifying through the weekend. This
leads to each afternoon getting warmer. The exception will be the
coastal locales as light winds Sunday and Monday especially should
result in a sea breeze each afternoon and early evening. Low
temperatures though will still be chilly due to good radiational
cooling conditions, with some places potentially having frost or
freeze conditions especially Saturday night.
For Tuesday through Thursday... While a coastal low is anticipated to
affect our weather, the details are less certain. This is due to the
timing of phasing energy toward the east coast, with a closed low
with the southern stream and a short wave arriving from the great
lakes region within the northern stream. The southern stream energy
will drive surface low pressure off the southeast u.S. Coast Tuesday
morning, then energy interaction between the northern and southern
streams will help turn the low northward by later Tuesday and
continue through Wednesday. The latest thinking is to bring the low
just off of our coast later Wednesday then into new england Thursday
morning. The combination of onshore flow (increasing moisture) and
increasing synoptic ascent will bring widespread rain mainly
Tuesday night and Wednesday. Some of the rain could be heavy at
times, however the system may be moving quick enough where the
window of opportunity for heavy rain is shortened.|
A period of stronger onshore flow could result in some coastal
flooding, although we are between the new full moon cycles. There is
still plenty of time to iron out the details, however given enough
agreement for widespread rain for a time we continued with likely to
low-end categorical pops for portions of this time frame. Initial
overunning rain should develop later Tuesday, with rain shifting
north Wednesday and then ending at night or early Thursday as low
pressure shifts to our northeast.
For Friday... An amplified upper-level trough may settle into the
east with some weak surface features moving through. Depending on
the evolution aloft, the airmass looks mild though and therefore
some showers cannot be ruled out if there is enough instability
during the day. As of now, we followed the wpc guidance rather
Aviation 01z Saturday through Wednesday
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
Tonight...VFR. High clouds move in toward early morning with
cigs at or above 15 kft agl. NW winds with sustained speeds
decreasing more gradually from 8-12 kt early this evening to
3-6 kt overnight.
Saturday...VFR with mid to high clouds (cigs above 10 kft agl).
Light NW winds 5-10 kt.
Saturday night...VFR. Northwest winds 5-10 knots, becoming mostly
light and variable.
Sunday...VFR. Light and variable winds, becoming south to southwest
around 5 knots (becoming southeast in the afternoon at acy, miv and
Monday...VFR. East to southeast winds around 5 knots.
Tuesday... MainlyVFR with increasing and gradually lower clouds,
then some light rain should develop at night. East-southeast winds
around 10 knots. Moderate confidence.
Wednesday... MVFR ifr conditions probable with a period of rain. A
period of gusty east to southeast winds possible, then lighter and
turning west to northwest at night. Low confidence with the
Tonight... Nw winds will continue to be in the 10-20 kt range
tonight. Short-period, wind-driven nwly swells will be in the
3-4 ft range in our coastal waters and 2 ft or less in the
Saturday... Nw winds 10-15 kt in the morning will become
light variable toward midday and then S by mid afternoon in
association with the development of a sea-breeze near the
coast. Mesoscale models show the S winds strengthening to near
15 kt with gusts to 20 kt late in the day in the coastal waters
Saturday night through Monday... .The conditions are expected to be
below small craft advisory criteria is over our area.
Tuesday and Wednesday... Small craft advisory conditions looking
likely. Low pressure is forecast to move up the east coast Tuesday
night through late Wednesday with onshore flow in advance of it.
Winds and seas therefore increase, with wind gusts anticipated as
of now to remain below gale force.
Phi watches warnings advisories
Pa... Frost advisory from 2 am to 8 am edt Saturday for paz102-104-
Freeze warning from 2 am to 8 am edt Saturday for paz060-101-
Nj... Frost advisory from 2 am to 8 am edt Saturday for njz012-013-
De... Frost advisory from 2 am to 8 am edt Saturday for dez001>003.
Md... Frost advisory from 2 am to 8 am edt Saturday for mdz012-015-
Freeze warning from 2 am to 8 am edt Saturday for mdz008.
near term... Klein po
short term... Klein
long term... Gorse
aviation... Gorse klein po
marine... Gorse klein po
Weather Reporting StationsEDIT (on/off)  Help NOTE: Click on distance to see the station location on a map
|Stations||Dist||Age||Wind||Air Temp||Water Temp||Waves||Pressure||DewPt|
|CA2 - 8571892 - Cambridge, MD||6 mi||54 min||45°F||53°F||1031.2 hPa|
|44062 - Gooses Reef, MD||19 mi||44 min||E 14 G 16||47°F||1030.7 hPa|
|COVM2 - 8577018 - Cove Point LNG Pier, MD||24 mi||54 min||ENE 18 G 21||46°F||1030.5 hPa|
|TPLM2 - Thomas Point, MD||25 mi||84 min||NE 17 G 20||46°F||50°F||1031.2 hPa (+2.0)||26°F|
|CPVM2||28 mi||54 min||46°F||25°F|
|BISM2 - 8571421 - Bishops Head, MD||30 mi||54 min||NNE 12 G 17||46°F||52°F||1030.2 hPa|
|SLIM2 - 8577330 - Solomons Island, MD||31 mi||54 min||NE 12 G 16||46°F||53°F||1029.6 hPa|
|APAM2 - 8575512 - Annapolis, MD||31 mi||54 min||45°F||1030.2 hPa|
|BSLM2 - Chesapeake Bay, MD||34 mi||114 min||ENE 2.9||46°F||1030 hPa||30°F|
|TCBM2 - 8573364 - Tolchester Beach, MD||39 mi||54 min||ESE 1 G 1||42°F||51°F||1030.9 hPa|
|PPTM2 - 8578240 - Piney Point, MD||44 mi||54 min||E 8.9 G 12|
|FSKM2 - 8574728 - Francis Scott Key Bridge, MD||45 mi||54 min||NNE 2.9 G 4.1||45°F||1030.8 hPa|
|44042 - Potomac, MD||45 mi||44 min||ENE 18 G 21||49°F||1030.7 hPa|
|DRSD1 - Delaware Reserve, DE||45 mi||114 min||N 4.1||43°F||1030 hPa||26°F|
|FSNM2||45 mi||54 min||NE 4.1 G 6||44°F||1030.2 hPa|
Wind History for Cambridge, MD(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
|Cambridge-Dorchester Airport, MD||9 mi||49 min||NNE 3||10.00 mi||Fair||43°F||26°F||53%||1030.5 hPa|
|Easton / Newman Field, MD||10 mi||35 min||NE 3||10.00 mi||Fair||39°F||28°F||64%||1031.8 hPa|
Wind History from CGE (wind in knots)
|1 day ago||N||N||N||N|
|2 days ago||NW|
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
Click for Map
Sat -- 12:52 AM EDT Moonset
Sat -- 02:15 AM EDT 0.30 feet Low Tide
Sat -- 06:20 AM EDT Sunrise
Sat -- 08:38 AM EDT 2.22 feet High Tide
Sat -- 10:59 AM EDT Moonrise
Sat -- 04:19 PM EDT 0.39 feet Low Tide
Sat -- 07:47 PM EDT Sunset
Sat -- 09:15 PM EDT 1.47 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|Cove Point (1.1 mi. NE of) |
Click for Map
Sat -- 12:52 AM EDT Moonset
Sat -- 01:23 AM EDT -0.37 knots Max Ebb
Sat -- 03:57 AM EDT 0.00 knots Slack
Sat -- 06:21 AM EDT Sunrise
Sat -- 07:26 AM EDT 0.73 knots Max Flood
Sat -- 11:01 AM EDT Moonrise
Sat -- 11:02 AM EDT -0.00 knots Slack
Sat -- 02:40 PM EDT -0.65 knots Max Ebb
Sat -- 06:04 PM EDT 0.00 knots Slack
Sat -- 07:47 PM EDT Sunset
Sat -- 08:23 PM EDT 0.34 knots Max Flood
Sat -- 11:15 PM EDT -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Weather Map and Satellite Images(on/off)  HelpWeather Map
GOES Local Image of Mid-Atlantic 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 Philadelphia/Mount Holly, PA (3,6,7,8)(on/off)  Help
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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.