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 6:13AM||Sunset 7:52PM||Monday April 23, 2018 6:59 PM EDT (22:59 UTC)||Moonrise 12:07PM||Moonset 1:41AM||Illumination 62%|
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|ANZ530 Chesapeake Bay North Of Pooles Island- 434 Pm Edt Mon Apr 23 2018 |
.small craft advisory in effect through late Tuesday night...
Rest of this afternoon..SE winds 10 kt with gusts to 20 kt. Waves 1 ft.
Tonight..E winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft.
Tue..E winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft. Rain. Vsby 1 to 3 nm.
Tue night..E winds 10 to 15 kt with gusts to 25 kt. Waves 1 to 2 ft. Rain.
Wed..NE winds 5 kt...becoming W in the afternoon. Waves 1 ft or less. Showers likely.
Wed night..NW winds 5 to 10 kt. Waves 1 ft. A chance of showers.
Thu..W winds 5 to 10 kt. Waves 1 ft or less.
Fri..S winds 5 kt. Waves less than 1 ft. A chance of showers.
|ANZ500 434 Pm Edt Mon Apr 23 2018 |
Synopsis for the tidal potomac and md portion of the chesapeake bay.. An area of low pressure over the tennessee valley and southeast u.s. Will approach the region tonight and Tuesday, crossing the waters on Wednesday. High pressure will then move near the area Thursday. Another low pressure system may affect the waters by Friday and Saturday. Small craft advisories may be needed Wednesday and Wednesday night.
7 Day Forecast for Marine Location Near Betterton, MDHourly EDIT Help
Area Discussion for - Philadelphia/Mount Holly, PA  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxus61 kphi 232223|
area forecast discussion
national weather service mount holly nj
623 pm edt Mon apr 23 2018
A large area of high pressure will shift slowly east of the
region overnight. A low in the lower mississippi valley will
lift into the mid atlantic states by Wednesday, with widespread
rain spreading across the region in advance of the system.
Another low pressure system passing to the south of our region,
could bring another chance of rain late this week. By late in
the weekend, high pressure begins to build south towards the
Near term until 6 am Tuesday morning
Quiet conditions will continue tonight across the area as high
pressure remains offshore of the new england coast. Our area
will remain under the influence of southeast return flow, which
will allow moisture to increase some overnight. Overnight lows
will drop through the night as winds diminish and mostly clear
skies will begin the night. However, with the flow being more
from the southeast, and the fact some clouds may begin moving in
late in the night, overnight lows are not expected to be as
cool as Sunday night. Most places should drop close to normal,
except portions of the pine barrens which might drop a few
degrees lower and have some patchy frost develop. We will
include patchy frost in the forecast, but not issue a frost
advisory yet as there is still uncertainty as to how low the
temperatures will get.
Short term 6 am Tuesday morning through 6 pm Tuesday
Dry conditions will begin the day Tuesday, before rain chances
increase through the day. An occluding low pressure system will
continue moving across the southern appalachians early in the day,
before slowing moving into the carolinas by the afternoon. Our area
will be well north of the low pressure system and the slowly lifting
warm front through the daytime hours. However, south-southwest flow
aloft will lead to increasing moisture through the day. A couple of
short wave vorticity impulses will lift across the area through the
day as well. Rain chances increase, especially during the afternoon
as the second of the short waves moves through and the best
moisture lift combination takes place. There is little to no
instability forecast, so no thunderstorms are expected at this time.
Winds will become gusty through the morning and into the afternoon
with gusts reaching 20 to 25 mph at times.
Long term Tuesday night through Monday
Overview: the main focus through this period remains on the
Tuesday night and Wednesday time frame and the potential for
heavy rain (though this threat appears to be decreasing).
After that, the next chance for rain looks to be primarily on
Saturday as our region will be in between a low off the coast
and a cold front approaching from the west.
Details: the low continues to very slowly progress northeast,
reaching the mid atlantic by Wednesday. The window for heavy
rain has narrowed a bit, now looks to be confined mainly late
Tuesday night, though lingering light rain is possible into
As for the heavy rain threat, precipitable water values on
Tuesday night are still expected to be well above normal,
possibly in the 90th percentile for this time of year. However,
there are a few factors working against the heavy rain threat.
The warm cloud layer is relatively shallow (generally 8000 to
9000 ft), thanks to continued below normal temperatures.
Additionally, storm motions aren't expected to be particularly
slow, around 20 mph, although training storms could make this
point moot. In general, it looks like the highest threat for
heavy rain will be over the coastal plains of DELMARVA and far
There is some very limited elevated instability Tuesday night,
but it is very elevated (generally for parcels at or above 850
mb). Thus, have not mentioned thunderstorms in the forecast for
now, but will continue to monitor this potential as we get
For the late week period, there remains some uncertainty in how
two low pressure systems, one lifting out of the southeast and
becoming a coastal low and one digging out of the north central
u.S., will interact and what the impact will be for our region.
However, the models today are in better agreement than what we
have seen the last few days, with a brief chance for rain on the
back side of the coastal low on Friday night or Saturday, and a
limited impact from the cold front moving in from the west.
Aviation 22z Monday through Saturday |
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
Tonight...VFR conditions will continue through tonight. Winds will
be from the south-southeast around 5-10 knots through this evening,
but will become light and variable most places overnight.
Tuesday...VFR conditions will begin the day across the TAF sites
through at least midday Tuesday. However, clouds will thicken and
lower through the afternoon, and could eventually reach MVFR by late
in the afternoon or early evening. Rain will also be moving from
the south during the afternoon hours.
Tuesday night and Wednesday... MVFR and even localized ifr
conditions will be possible especially through Wednesday
morning as periods of rain are likely across the region.
Easterly wind gusts up to 20 kt are possible. Moderate
confidence on flight categories, but low confidence on the
timing of any flight category changes.
Thursday...VFR conditions expected with light westerly winds.
Friday and Saturday... MostlyVFR conditions are likely, though
there is a chance that rain and low clouds could lower
conditions to MVFR at times. Wind is forecast to be westerly or
southwesterly near or below 10 kt. Moderate confidence on
flight categories and wind.
Conditions will remain below advisory levels tonight and into the
first half of Tuesday. However, winds could begin gusting around 25
knots by the afternoon, while seas are expected to build to 5 feet
or higher by the afternoon as well. Therefore the small craft
advisory remain in place starting noon Tuesday.
Tuesday night and Wednesday... Easterly and southeasterly winds
increase to 15-20 kt with gusts up to 30 kt, and seas build up
to 10 feet on the atlantic coastal waters. Wind gusts near 25 kt
are also expected on the delaware bay primarily Tuesday night.
Wednesday night and Thursday... Winds shift to northwesterly and
should decrease. The main question will be how long seas remain
above 5 feet on the coastal waters. Current forecast is for
elevated seas into late Thursday, but there is still
considerable uncertainty with this.
Friday and Saturday... Winds and seas are currently forecast to
stay below SCA criteria on all waters. However, there remains
some uncertainty with if a coastal low develops and intensifies.
If this happens, there is a slight chance for SCA criteria,
primarily on Saturday.
Relative humidity values dropped once again today, similarly to
Sunday, into the 20 and even teens in some areas. However, winds
have not been very windy except occasional gusts in the teens to
around 20 mph in a few spots. The low humidity values will continue
into sunset, while winds may increase slightly. However, since winds
are not gusting frequently or widespread, we are not expecting any
enhanced statements at this time. While it will be a bit more breezy
and gusty Tuesday, relative humidity values will be higher on
Tuesday than today, and rain will overspread the area by
afternoon. So no enhanced statements are expected on Tuesday.
Phi watches warnings advisories
Marine... Small craft advisory from noon Tuesday to 6 pm edt Wednesday
Small craft advisory from noon Tuesday to 2 am edt Wednesday
Synopsis... Johnson 99
near term... Robertson 99
short term... Robertson
long term... Johnson
aviation... Johnson robertson 99
marine... Johnson robertson
fire weather... Robertson
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|
|TCBM2 - 8573364 - Tolchester Beach, MD||15 mi||41 min||SSW 12 G 14||58°F||55°F||1028.8 hPa|
|CHCM2 - 8573927 - Chesapeake City, MD||16 mi||47 min||ESE 6 G 8.9||64°F||54°F||1028.7 hPa|
|FSNM2||28 mi||137 min||SSE 11 G 13||64°F||1027.7 hPa|
|FSKM2 - 8574728 - Francis Scott Key Bridge, MD||28 mi||41 min||S 15 G 18||63°F||1028.1 hPa|
|DELD1 - 8551762 - Delaware City, DE||28 mi||41 min||SSE 8.9 G 13||60°F||51°F||1028.9 hPa|
|RDYD1 - 8551910 - Reedy Point, DE||28 mi||41 min||60°F||52°F||1028.6 hPa|
|BLTM2 - 8574680 - Baltimore, MD||29 mi||41 min||SSW 4.1 G 11||64°F||55°F||1028 hPa|
|CPVM2||32 mi||41 min||57°F||43°F|
|APAM2 - 8575512 - Annapolis, MD||35 mi||41 min||62°F||1028.2 hPa|
|DRSD1 - Delaware Reserve, DE||37 mi||149 min||ESE 8||61°F||1030 hPa||43°F|
|TPLM2 - Thomas Point, MD||39 mi||179 min||S 9.9 G 12||58°F||55°F||1029.8 hPa||45°F|
|MRCP1 - 8540433 - Marcus Hook, PA||45 mi||41 min||62°F||53°F||1028.7 hPa|
Wind History for Tolchester Beach, MD(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
|Baltimore / Martin, MD||20 mi||74 min||SSE 9||10.00 mi||Mostly Cloudy||66°F||50°F||56%||1028.4 hPa|
Wind History from APG (wind in knots)
|1 day ago||S||S||SE||S||SW||W||SW||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||E||E||E||SE||NE||NE||Calm|
|2 days ago||N||NW||NW|
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
Click for Map
Mon -- 02:41 AM EDT Moonset
Mon -- 03:50 AM EDT 1.76 feet High Tide
Mon -- 06:15 AM EDT Sunrise
Mon -- 09:48 AM EDT 0.44 feet Low Tide
Mon -- 01:06 PM EDT Moonrise
Mon -- 04:18 PM EDT 2.30 feet High Tide
Mon -- 07:49 PM EDT Sunset
Mon -- 11:22 PM EDT 0.48 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|Chesapeake and Delaware Canal |
Click for Map
Mon -- 01:42 AM EDT 1.74 knots Max Flood
Mon -- 02:40 AM EDT Moonset
Mon -- 03:57 AM EDT -0.09 knots Slack
Mon -- 06:14 AM EDT Sunrise
Mon -- 07:35 AM EDT -2.08 knots Max Ebb
Mon -- 11:21 AM EDT 0.00 knots Slack
Mon -- 01:05 PM EDT Moonrise
Mon -- 02:29 PM EDT 2.14 knots Max Flood
Mon -- 05:55 PM EDT -0.01 knots Slack
Mon -- 07:49 PM EDT Sunset
Mon -- 08:27 PM EDT -1.58 knots Max Ebb
Mon -- 11:57 PM EDT 0.02 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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Wind Forecast for Philadelphia/Mount Holly, PA (18,4,5,8)(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.