Marine Weather and Tides
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.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.
|Sunrise 6:06AM||Sunset 7:56PM||Saturday April 29, 2017 7:26 AM EDT (11:26 UTC)||Moonrise 7:59AM||Moonset 10:40PM||Illumination 12%|
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|ANZ540 Eastern Bay- 432 Am Edt Sat Apr 29 2017 |
Rest of the overnight..S winds 10 kt. Waves 1 ft. A slight chance of showers and tstms.
Today..SW winds 10 kt. Waves 1 ft. A chance of showers and tstms.
Tonight..S winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms.
Sun..SE winds 5 to 10 kt. Waves 1 ft or less.
Sun night..S winds 5 to 10 kt. Waves 1 ft.
Mon..S winds 10 to 15 kt with gusts to 25 kt. Waves 2 ft. A chance of showers and tstms.
Mon night..SW winds 10 to 15 kt with gusts to 20 kt. Waves 2 ft. Showers and tstms likely.
Tue..W winds 10 to 15 kt. Waves 1 to 2 ft. A chance of showers in the morning.
Wed..W winds 5 to 10 kt...becoming e. Waves 1 ft. A chance of showers through the night. Winds and waves higher and visibilities lower in and near tstms.
|ANZ500 432 Am Edt Sat Apr 29 2017 |
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A semi-stationary frontal boundary just north of the mason-dixon line will move south this afternoon and remain over the waters through early Sunday...before lifting north as a warm front late Sunday afternoon. A cold front will cross the mid-atlantic Monday night with canadian high pressure then building over the area through Wednesday. A small craft advisory is likely Monday into Tuesday.
7 Day Forecast for Marine Location Near Grasonville, MDHourly EDIT Help
Area Discussion for - Philadelphia/Mount Holly, PA  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxus61 kphi 291037|
area forecast discussion
national weather service mount holly nj
637 am edt Sat apr 29 2017
A cold front is expected to slide south into our region tonight
before stalling over DELMARVA and south jersey. The front is
expected to return north as a warm front late tomorrow. Another cold
front is expected on Monday night as an area of low pressure moves
into the great lakes region. This low will drift northeast through
eastern canada through mid week. Another low pressure system will
lift out of the lower mississippi valley towards the mid atlantic by
late in the week.
Near term /until 6 pm this evening/
This first round of showers and thunderstorms has moved to the
east and offshore as the first short wave has passed to our
east. We should have a break in shower/thunderstorm activity,
before another round of showers and thunderstorms moves into
the area later this morning into the the noon hour as a second
short wave/vorticity impulse moves across the area. This area
should weaken move to our east as the second short wave passes
to the east.
Then yet another round of showers and thunderstorms is possible by
late this afternoon into this evening as a backdoor cold front moves
into the area and another short wave slides across the area as well.
This batch of showers and thunderstorms will have more surface based
instability to tap into and less of a cap. So it could be possible
that an isolated severe thunderstorm could develop late today.
Temperatures today will warm quite significantly and come withing a
couple of degrees for some areas. Ged is the one site that is
actually forecast to reach a record.
Short term /6 pm this evening through 6 am Sunday/
The backdoor cold front will continue to push through the area this
evening and overnight. The round of showers and thunderstorms
mentioned for the late afternoon and evening will slide east and
move offshore during the evening hours as the short
wave/vorticity impulse associated with it moves to our east as
As the front sinks to our south, a northeast-east flow will develop
across the area. There could be some light fog develop overnight,
but we do not expect much if any dense fog at this time as winds
will remain around 5-10 mph through the night and dewpoints are
expected to drop enough behind the front that rh values do not reach
high enough for widespread fog for most places.
With the front near the area, it is possible that some
isolated/scattered showers may develop overnight through daybreak
Sunday north of the frontal boundary.
Long term /Sunday through Friday/
Sunday... There is some question on how far south the front will
reach before stalling. The general trend with the 00z models was
to bring the front further south (possibly entirely south of our
forecast area). Where the front stalls will have implications
for both high temperatures Sunday as well as precip chances. As
mentioned by the previous shift, the GFS appears to be
overestimating the precip north of the front given relatively
dry air in the cool sector. Therefore, focused the pops through
this period on DELMARVA closer to the front. The front is
expected to return north as a warm front either late in the day
tomorrow or tomorrow night.
Monday... With the cold front still over the ohio valley, expect
a mostly sunny and dry day. A brisk south- west flow will
develop, with wind gusts up to around 30 mph in the afternoon.
Temperatures will be well above normal, with highs in the low
80s across the urban corridor. With the cold frontal passage
Monday night, showers and thunderstorms are likely. While the
timing is not ideal for severe weather and instability is
limited, the wind field is strong and precipitable water values
approach 2.0 inches, so gusty winds and heavy downpours are
likely with any thunderstorms, the primary focus being northwest
of the nj turnpike/i-95.
Tuesday and Wednesday... In the wake of the cold front,
temperatures will be about 5 to 10 degrees lower, with highs
generally in the 60s and 70s. Models have trended faster with
the dry air advection behind the front, so I trimmed back on
the pops on Tuesday. It is looking mostly dry both days.
Unsettled weather during the Thursday and Friday time frame. A broad
trough to our west will maintain a southwest flow aloft, along with
moisture of gulf of mexico origins moving up the eastern
seaboard, within an overrunning regime. Heavy rainfall is
certainly possible, with wpc guidance indicating the potential
for 1-2 inches across our region, but there is still inherent
uncertainty given it's day 6-7. Stay tuned.
Aviation /10z Saturday through Wednesday/
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
The first round of showers and thunderstorms has moved east of
the area early this morning. Some patchy light fog will occur at
a few sites early this morning. Then another round of showers,
possible thunderstorms, could affect the TAF sites later this
morning. Another round of showers and thunderstorms is more
likely later this afternoon which has a better chance of being
stronger storms with reductions to conditions.
Outside of the showers and thunderstorms,VFR conditions will
prevail through the daytime hours. However, as a backdoor cold front
sinks through the area later this evening and overnight, we expect
lower clouds and light fog to develop. At this time, we only
expect conditions to lower to MVFR, but there is the possibility|
that conditions could lower to ifr overnight.
Winds are variable at many locations, but are generally out of the
southeast to south for most places where there is any direction.
Winds will increase out of the southwest this morning, before
becoming west then northwest through the day and into the afternoon
and evening. Winds could gust 15-20 knots for a period this
afternoon as well. Behind the frontal passage, winds will become
northeast this evening and overnight.
Sunday... MostlyVFR conditions expected.
Sunday night... MVFR or ifr conditions are possible with low clouds
Monday... MostlyVFR conditions are expected although MVFR conditions
are possible with any showers or thunderstorms.
Monday night... Widespread MVFR or ifr conditions with thunderstorms
likely. An abrupt wind shift to westerly is expected with a cold
front Monday night.
Tuesday and Wednesday... MostlyVFR conditions expected.
Conditions on the coastal waters are expected to remain below small
craft advisory levels through today and tonight. Even though there
are some strong winds above the surface, there is a strong inversion
which will keep those winds fro mixing to the surface. However,
winds could gust around 20 knots and seas could reach 4 feet at
times through the day.
There is a chance of showers and thunderstorms across the waters.
Any thunderstorms will contain frequent lightning and may cause
strong gusty winds.
Sunday... Winds and seas are expected to be below SCA criteria.
Monday and Monday night... Building seas and increasing winds are
expected by Monday morning. Southerly gusts near or above 30 kt
are possible Monday evening.
Tuesday and Wednesday... Winds will shift to southwesterly and
then westerly behind a cold front expected early Tuesday. Gusts
on Tuesday may linger near 25 kt. Elevated seas may linger into
Record high temps listed today where it is forecast to be
within 2 degrees of record.
ttn 88- 1974 & 1888
**record or number 2 warmest april on record expected**
presuming our forecast temps these last 2 days of april are
accurate, we are assured of a top 2 warmest april on record in
much of our forecast area. Sunday is probably the critical day
for determining record or not.
Below: april projected within the top april average temps, the
normal for april and the period of record (por).
This includes Friday's (28th) high and low temperatures through
Sundays MAX temps may occur at 1 am and the min temps Sunday
Phl normal 54.0 por 1874
59.5 2017 projected warmest ever: still could slip .2 degrees.
abe normal 49.9 por 1922
56.9 projecting record and almost cant miss a record.
acy normal 51.7 por 1874
57.6 projecting record and almost cant miss.
near term... Robertson
short term... Robertson
long term... Franck/johnson
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|
|TPLM2 - Thomas Point, MD||10 mi||26 min||SSW 12 G 12||66°F||60°F|
|CPVM2||11 mi||38 min||66°F||66°F|
|44063 - Annapolis||12 mi||26 min||WSW 12 G 16||70°F||61°F||1 ft||1015.5 hPa (-1.0)|
|APAM2 - 8575512 - Annapolis, MD||14 mi||38 min||71°F||1015.2 hPa|
|44043 - Patapsco, MD||20 mi||26 min||S 5.8 G 7.8||66°F||63°F||1 ft||1016 hPa (-1.4)|
|TCBM2 - 8573364 - Tolchester Beach, MD||23 mi||38 min||SSW 8.9 G 14||70°F||62°F||1015.3 hPa|
|CA2 - 8571892 - Cambridge, MD||23 mi||44 min||71°F||65°F|
|44062 - Gooses Reef, MD||24 mi||26 min||W 14 G 14||69°F||56°F||1 ft||1016.5 hPa (-0.9)|
|BSLM2 - Chesapeake Bay, MD||25 mi||116 min||SSE 5.1||67°F||1017 hPa||64°F|
|FSNM2||28 mi||38 min||WSW 8 G 13||73°F||1015.1 hPa|
|FSKM2 - 8574728 - Francis Scott Key Bridge, MD||28 mi||38 min||WSW 8.9 G 11||72°F||1015.2 hPa|
|BLTM2 - 8574680 - Baltimore, MD||32 mi||38 min||W 4.1 G 6||72°F||65°F||1015 hPa|
|COVM2 - 8577018 - Cove Point LNG Pier, MD||34 mi||38 min||SW 20 G 24||74°F||1016.7 hPa|
|SLIM2 - 8577330 - Solomons Island, MD||40 mi||38 min||SSW 16 G 20||72°F||62°F|
|WASD2 - 8594900 - Washington, DC||41 mi||38 min||S 4.1 G 7||71°F||67°F||1016 hPa|
|44057 - Susquehanna, MD||47 mi||26 min||N 3.9 G 5.8||69°F||62°F||1015.3 hPa (-0.6)|
|BISM2 - 8571421 - Bishops Head, MD||47 mi||38 min||SSW 12 G 14||70°F||68°F||1018.3 hPa|
Wind History for Cambridge, MD(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
|Bay Bridge Field, MD||8 mi||46 min||S 11||7.00 mi||Fog/Mist||72°F||68°F||88%||1015.2 hPa|
|Easton / Newman Field, MD||11 mi||96 min||SW 6||7.00 mi||Overcast||72°F||68°F||88%||1018.3 hPa|
|Annapolis, United States Naval Academy, MD||14 mi||92 min||S 6||7.00 mi||Fair||72°F||71°F||97%||1015.2 hPa|
Wind History from W29 (wind in knots)
|1 day ago||SE||SE||SE||NW||Calm||S||SE||S|
|2 days ago||N||NW||NW||N||N||N||NW||NW||Calm||E||S||SE||Calm||Calm||Calm||SE||Calm||E||E||E||E||SE||E |
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
Click for Map
Sat -- 12:33 AM EDT 0.15 feet Low Tide
Sat -- 06:09 AM EDT Sunrise
Sat -- 07:01 AM EDT 1.97 feet High Tide
Sat -- 08:59 AM EDT Moonrise
Sat -- 02:25 PM EDT 0.21 feet Low Tide
Sat -- 07:32 PM EDT 1.24 feet High Tide
Sat -- 07:55 PM EDT Sunset
Sat -- 11:40 PM EDT Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|Baltimore Harbor Approach |
Click for Map
Sat -- 01:35 AM EDT -0.74 knots Max Ebb
Sat -- 04:17 AM EDT 0.00 knots Slack
Sat -- 06:09 AM EDT Sunrise
Sat -- 07:56 AM EDT 1.24 knots Max Flood
Sat -- 08:59 AM EDT Moonrise
Sat -- 11:22 AM EDT -0.00 knots Slack
Sat -- 02:40 PM EDT -1.14 knots Max Ebb
Sat -- 06:17 PM EDT 0.00 knots Slack
Sat -- 07:56 PM EDT Sunset
Sat -- 08:50 PM EDT 0.61 knots Max Flood
Sat -- 11:32 PM EDT -0.00 knots Slack
Sat -- 11:41 PM EDT Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Weather Map and Satellite Images(on/off)  Help
|Weather Map ||IR Satellite Image from GEOS|
GOES Local Image of Mid-Atlantic EDIT
Wind Forecast for Philadelphia/Mount Holly, PA (7,2,3,4)(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.