Wednesday, April25, 2018

Marine Weather and Tides
Grasonville, MD

Version 3.4
What's New / NOTES
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 6:11AMSunset 7:52PM Wednesday April 25, 2018 1:54 PM EDT (17:54 UTC) Moonrise 2:22PMMoonset 3:04AM Illumination 79% Phase: Waxing Gibbous; Moon at 10 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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ANZ540 Eastern Bay- 134 Pm Edt Wed Apr 25 2018
.small craft advisory in effect from 9 pm edt this evening through Thursday morning...
This afternoon..N winds 5 kt. Waves less than 1 ft. A chance of rain and drizzle. Patchy fog. Vsby 1 to 3 nm.
Tonight..NW winds 5 to 10 kt. Gusts up to 20 kt in the late evening and overnight. Waves 1 ft. A chance of showers. Patchy fog. Vsby 1 to 3 nm.
Thu..W winds 5 to 10 kt. Gusts up to 20 kt until late afternoon. Waves 1 to 2 ft.
Thu night..S winds 5 kt. Waves less than 1 ft. Rain.
Fri..S winds 5 to 10 kt. Waves 1 ft. Rain.
Fri night..SW winds 5 to 10 kt. Waves 1 ft or less. A chance of showers.
Sat..NW winds 5 to 10 kt. Waves 1 ft. A chance of showers.
Sun..NW winds 5 to 10 kt. Waves 1 ft.
ANZ500 134 Pm Edt Wed Apr 25 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will pass through the waters today. High pressure will approach the waters tonight before settling overhead Thursday. Low pressure will approach the waters Thursday night before passing through Friday. A cold front will pass through Saturday and high pressure will return for early next week.

7 Day Forecast for Marine Location Near Grasonville, MD
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location: 38.88, -76.25     debug

Area Discussion for - Philadelphia/Mount Holly, PA
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Fxus61 kphi 251650
area forecast discussion
national weather service mount holly nj
1250 pm edt Wed apr 25 2018

Low pressure will move across our area today then into new england
tonight and Thursday. The next low pressure system moves across the
east coast during Friday, then a cold front moves through on
Saturday. High pressure builds into our region Monday before
gradually shifting just off the mid-atlantic coast Tuesday.

Near term until 6 pm this evening
Low pressure is now centered over southeastern virginia, and
continues to lift to the north and east. It should be over
delmarva this afternoon, and will continue its northern track
towards nyc by this evening. Meanwhile, an upper trough over the
great lakes tracks east through the day and moves into western
ny pa by this evening as well.

Rain continues to move northward through northern new jersey
and northeastern pennsylvania this afternoon. Some light
rain drizzle and fog continues through central portions of the

Additionally, dense fog has developed along the coastal areas of
new jersey and delaware. With visibilities starting to drop
between 1 2 and 1 4 mile as seen on local beach cams, we have
issued a dense fog advisory for the immediate coastal sections
through 7 pm tonight.

Dry slot continues to work its way up through DELMARVA and into
southern new jersey and southeastern pennsylvania. As it continues
to lift north through the region during this afternoon, the
upper trough begins to dig into the northeast us. This results
in scattered showers for the afternoon and early evening. There
may be enough elevated instability for some isolated
thunderstorms, mainly across southeast nj and into the delmarva.

Will go ahead and add isolated thunderstorms for those areas,
but not expecting much convection.

The rain and clouds will keep northern portions of the forecast
area relatively colder than the rest of the region, and highs
will top off in the 50s to low 60s north and west of the fall
line. For southern nj, southeast pa, and parts of delmarva,
there should be a break in the precip and possibly a break in
the clouds that result in warmer temps, and highs will get into
the mid and upper 60s.

Clouds have broken up more than anticipated in southern
delaware, resulting in a quick jump in temperatures. Highs will
reach into the low to mid 70s in areas that see good break and
plenty of sunshine through the cloud cover this afternoon.

Short term 6 pm this evening through 6 am Thursday
Upper trough passes north of the region tonight, and several strong
shortwaves will lift through the mid-atlantic and northeast. This
will keep some showers in the region, with the best chances in
northern nj and the southern poconos. Showers taper off after
midnight as this system departs. Winds shift to the northwest, and
conditions will dry out towards daybreak Thursday.

Lows range from the 40s to low 50s.

Long term Thursday through Tuesday
Summary... Some showers at times into the weekend, then a significant
warm-up probable starting early next week.

Synoptic overview... An upper-level trough from the plains to the
east coast initially has several strong short wave troughs embedded
within, however with time this consolidates into one main trough in
the east. This is forecast to take place through the weekend, then
strong energy rolling through the western u.S. Allows for a ridge to
build in the plains during the weekend which then shifts eastward
early next week. Due to the initial multiple short wave troughs
within the larger trough, timing can be less certain as well as the
strength of the surface features which impacts the details. The
overall pattern favors milder air overall (Sunday the coolest day),
then as we transition to an incoming ridge early next week
the development of significant warmth is probable.

For Thursday... A strong short wave trough lifts up across the
northeast with northwesterly flow in its wake across our area. The
main synoptic ascent is forecast to be to our northeast, therefore a
dry forecast is carried for during the daytime. There will be a
northwest breeze and with this downsloping especially into the
coastal plain results in mild temperatures. A period of dry air
advection should help to erode the clouds, however additional clouds
will be on the increase at night as a short wave trough rotating
around the main trough aloft approaches from the southwest. Some
showers with this may arrive into our southwestern areas late at

For Friday... As the main upper-level trough becomes more
consolidated, a short wave trough tracks up its east side and across
the mid-atlantic and northeast. This feature looks to open up and
start to shear out as it tracks northeastward, however plenty of
lift with it as it takes on some initial negative tilt should
produce showers especially through early afternoon. A weak surface
low may accompany it and this may help maintain some showers into
early Friday evening. It is not out of the question that enough
instability develops Friday afternoon for some thunder, however
opted to leave it out for now. Widespread low clouds accompanying
the showers may limit the overall heating potential, therefore
leaned toward the cooler guidance for high temperatures. There
should be some improving conditions at night.

For Saturday and Sunday... The upper-level trough sharpens some
across the northeast and northern mid-atlantic region Saturday as a
ridge shifts eastward from the plains. There may be enough
instability Saturday (especially the afternoon) with strong short
wave energy glancing the area and a cold front moving through to
produce some showers, especially across the northern half of the
area. Despite the incoming upper-level trough, mild air should hang
on during Saturday then cooling arrives at night and Sunday as the
trough axis crosses our area. Sunday is expected to be dry with a
northwest breeze as high pressure starts to build in from the west.

For Monday and Tuesday... As the pattern shifts to a trough out west,
a ridge shifts eastward and this drives surface high pressure over
the mid-atlantic region Monday then just offshore on Tuesday. The
presence of the building ridge will result in warm air advection and
therefore a probable significant warm-up starting during this time
frame. Given the presence of surface high pressure with a ridge
aloft, dry conditions are forecast.

Aviation 18z Wednesday through Monday
The following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.

Today... Light to moderate rain across the terminals with ifr
conditions prevailing. Some local lifr conditions possible as
well. Rain tapers off from south to north by early afternoon,
and then additional showers are possible this afternoon.

Generally ifr cigs, lifting to MVFR late this afternoon. Cannot
rule out a thunderstorm this afternoon, mainly at kacy. East
winds 10-15 kt, becoming lgt vrb late this afternoon.

Tonight... Scattered showers through midnight or so. Ifr CIGS lift to
vfr after midnight. Lgt vrb winds in the evening become NW 10 kt or
less by daybreak Thursday.


Thursday...VFR during the day, then MVFR (locally ifr) ceilings may
develop as showers arrive by late night. West-northwest winds 10-15
knots, then diminishing in the evening. Low confidence with onset of
sub-vfr conditions.

Friday... MVFR (locally ifr) with showers, then conditions should
improve toVFR especially at night.

Saturday... MostlyVFR, with a few daytime showers possible.

Sunday...VFR. Northwest winds may gust up to 25 knots, then diminish
toward late day and in the evening.

Lowered the SCA on the de bay as winds have finally dropped
below 25 knots at brandywine light shoal. For the ocean, wind
gusts of 25-30 kt through this afternoon, but seas remain
elevated through tonight.

We have expanded the dense fog advisory to include all of the nj
and de coastal waters through 7pm tonight. Web cams show a
strong layer of fog along the coast and it is expected to
continue through tonight. Some erosion of the fog bank near
delaware can be seen on visible satellite images but confidence
is not high that the fog will erode enough to drop the

Otherwise, scattered showers expected through this afternoon. A
few thunderstorms are possible on the waters late this
afternoon and early this evening.


Thursday... Small craft advisory for the atlantic coastal waters due
to elevated seas. The seas however should subside some at night.

Friday and Saturday... A small craft advisory may be needed for a
time for the atlantic coastal waters. The winds should be below
advisory criteria, however southeasterly flow ahead of a system may
be enough to build the seas to around 5 feet.

Sunday... The conditions are anticipated to be below small craft
advisory criteria, although wind gusts to around 20 knots may
occur nearshore during the day.

Phi watches warnings advisories
Pa... None.

Nj... Dense fog advisory until 7 pm edt this evening for njz014-

De... Dense fog advisory until 7 pm edt this evening for dez004.

Md... None.

Marine... Dense fog advisory until 7 pm edt this evening for anz450>455.

Small craft advisory until 6 pm edt Thursday for anz450>455.

Synopsis... Gorse
near term... Meola mps
short term... Mps
long term... Gorse
aviation... Gorse meola mps
marine... Gorse meola mps

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
TPLM2 - Thomas Point, MD 10 mi54 min NNE 8 G 8.9 57°F 53°F1007.1 hPa (-1.5)57°F
CPVM2 11 mi54 min 57°F 57°F
APAM2 - 8575512 - Annapolis, MD 14 mi54 min 63°F 1005.6 hPa (-1.7)
TCBM2 - 8573364 - Tolchester Beach, MD 23 mi54 min N 8 G 8.9 57°F 54°F1006.4 hPa (-1.7)
CA2 - 8571892 - Cambridge, MD 23 mi54 min 66°F 55°F1006.5 hPa (-1.8)
44062 - Gooses Reef, MD 24 mi44 min NNE 7.8 G 7.8 55°F 1006.7 hPa
BSLM2 - Chesapeake Bay, MD 25 mi144 min NNE 1.9 54°F 1007 hPa53°F
FSNM2 28 mi60 min ENE 4.1 G 5.1 59°F 1006.2 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 28 mi54 min ENE 2.9 G 4.1 60°F 1006.4 hPa (-1.6)
BLTM2 - 8574680 - Baltimore, MD 32 mi54 min SSW 2.9 G 4.1 61°F 56°F1006.1 hPa (-1.6)
COVM2 - 8577018 - Cove Point LNG Pier, MD 34 mi54 min N 8.9 G 11 55°F 1006.6 hPa (-1.5)
SLIM2 - 8577330 - Solomons Island, MD 40 mi54 min N 6 G 8 59°F 54°F1005.4 hPa (-1.6)
WASD2 - 8594900 - Washington, DC 41 mi54 min NNW 4.1 G 8 62°F 56°F1006.6 hPa (-1.2)
DRSD1 - Delaware Reserve, DE 45 mi144 min E 2.9 57°F 1007 hPa57°F
BISM2 - 8571421 - Bishops Head, MD 47 mi54 min S 2.9 G 2.9 60°F 57°F1006.3 hPa (-1.5)

Wind History for Cambridge, MD
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1 day
2 days

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Bay Bridge Field, MD8 mi79 minNNW 63.50 miFog/Mist59°F57°F94%1006.8 hPa
Easton / Newman Field, MD11 mi64 minN 310.00 miOvercast66°F59°F78%1007.1 hPa
Annapolis, United States Naval Academy, MD14 mi60 minNNW 710.00 miOvercast63°F57°F81%1006.3 hPa

Wind History from W29 (wind in knots)
Last 24hrSE13
1 day agoW5W9SW10S7
2 days agoS7SE6SW6W6SW6S6S4CalmCalmSE4SE4SE5SE3CalmCalmE3CalmCalmSE5S4CalmSE6W8NW6

Tide / Current Tables for Claiborne, Eastern Bay, Maryland
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Wed -- 12:49 AM EDT     1.40 feet High Tide
Wed -- 04:04 AM EDT     Moonset
Wed -- 06:14 AM EDT     Sunrise
Wed -- 07:30 AM EDT     0.27 feet Low Tide
Wed -- 01:23 PM EDT     1.46 feet High Tide
Wed -- 03:22 PM EDT     Moonrise
Wed -- 07:51 PM EDT     Sunset
Wed -- 08:13 PM EDT     0.32 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Tide / Current Tables for Baltimore Harbor Approach, Maryland Current
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Baltimore Harbor Approach
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Wed -- 02:09 AM EDT     0.74 knots Max Flood
Wed -- 04:04 AM EDT     Moonset
Wed -- 05:16 AM EDT     -0.00 knots Slack
Wed -- 06:14 AM EDT     Sunrise
Wed -- 08:14 AM EDT     -0.68 knots Max Ebb
Wed -- 11:11 AM EDT     0.00 knots Slack
Wed -- 02:22 PM EDT     0.79 knots Max Flood
Wed -- 03:22 PM EDT     Moonrise
Wed -- 05:26 PM EDT     -0.00 knots Slack
Wed -- 07:52 PM EDT     Sunset
Wed -- 08:41 PM EDT     -0.88 knots Max Ebb
Wed -- 11:52 PM EDT     0.00 knots Slack
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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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 Philadelphia/Mount Holly, PA (13,3,4,5)
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Ground Weather Radar Station Dover AFB, DE
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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 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 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.