Sunday, April22, 2018

Marine Weather and Tides
Denton, 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 6:15AMSunset 7:49PM Sunday April 22, 2018 5:54 PM EDT (21:54 UTC) Moonrise 11:01AMMoonset 12:49AM Illumination 51% Phase: First Quarter Moon; Moon at 7 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- 433 Pm Edt Sun Apr 22 2018
Rest of this afternoon..S winds 10 kt. Waves 1 ft.
Tonight..SE winds 5 to 10 kt. Waves 1 ft.
Mon..SE winds 10 to 15 kt. Waves 1 ft.
Mon night..SE winds 10 to 15 kt. Waves 1 ft. A chance of rain.
Tue..E winds 10 to 15 kt with gusts to 20 kt. Waves 1 to 2 ft. Rain.
Tue night..E winds 10 to 15 kt with gusts to 20 kt. Waves 2 ft. Rain.
Wed..NE winds 5 to 10 kt...becoming nw. Waves 1 ft. Rain in the morning, then showers likely through the night. A chance of showers after midnight.
Thu..S winds 5 to 10 kt. Waves 1 ft. A chance of showers.
ANZ500 433 Pm Edt Sun Apr 22 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. High pressure will remain centered over the great lakes region through tonight before moving off the new england coast Monday. An area of low pressure over the deep south will approach the region mid week. Small craft advisories may be needed Tuesday.

7 Day Forecast for Marine Location Near Denton, MD
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location: 38.88, -75.83     debug

Area Discussion for - Philadelphia/Mount Holly, PA
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Fxus61 kphi 221947
area forecast discussion
national weather service mount holly nj
347 pm edt Sun apr 22 2018

Large area of high pressure over the northeastern united states will
continue to slowly build east, building off shore by tomorrow.

Meanwhile, a low in the deep south will slowly lift into the mid
atlantic states by mid week. Another low pressure system and its
associated cold front could affect our region late in the week.

Near term until 6 am Monday morning
An upper-level trough axis will shift east of our region this
evening along with a stronger embedded short wave. As this occurs, a
250 mb jet streak will continue to shift to our east as well. Given
the positioning of the upper-level jet streak, the high level clouds
have remained much more thinned this afternoon even across the
southern zones. However, a small area of mid level cloud has
developed across parts of southern delaware where there appears to
be some local convergence occurring with a sea breeze boundary and
there are higher dew points just to the south. In addition, there
continues to be areas of thicker high level clouds across west
virginia to virginia and if these hold together then they may skirt
parts of our DELMARVA zones through this evening. Otherwise, a
mainly clear sky is anticipated. A sea breeze gradually working its
way inland is allowing for much cooler air to its east along with a
bit more of a southeasterly breeze.

The presence of a ridge gradually approaching from the west is
resulting in expansive surface high pressure across the mid-atlantic
and northeast. This will continue to provide ample dry air and
enough low-level subsidence, along with winds going light and
variable to calm. Any wind should drop off quickly this evening.

This will set the stage for good radiational cooling conditions,
however the airmass looks to be moderating some. We are still
expecting it to be a chilly night (mostly closer to daybreak) given
the lack of clouds, light winds and dry air. Speaking of dry air,
the surface dew points dropped considerably today for much of the
area with ample boundary layer warmth. These are expected to recover
some through the evening as the boundary layer warmth wanes and a
residual sea breeze front marches inland more before dissipating.

There very well can be some frost toward daybreak, especially in the
pine barrens of new jersey and portions of southeastern pennsylvania
however this may be more patchy. For this reason, we opted not to
issue a frost advisory at this time.

Low temperatures are mostly a multi-model blend with continuity,
then some local adjustments were applied to account for local better
radiational cooling.

Short term 6 am Monday morning through 6 pm Monday
The dry conditions continue as an upper-level ridge gradually slides
over our area during the afternoon. This will place the center of
surface high pressure closer to coastal new england, resulting in
south to southeast low-level flow across our area. This is all ahead
of a closed low that is forecast to be traversing the gulf coast
states and the tennessee valley region.

The presence of the ridge aloft should limit any clouds to the high
level variety and this is mainly for portions of delmarva. The low-
level flow looks a little stronger during the afternoon, and the
gradient flow becomes more from the southeast therefore this will
result in some cooling across eastern new jersey and parts of
delaware. Quick warming through the morning though may set up a sea
breeze front which then should just be enhanced some by the
southeasterly gradient low-level flow. High temperatures are mostly
a MOS continuity blend, which ends up being warmer from
previously for inland areas given a bit of warming aloft.

Long term Monday night through Sunday
Overview: the first focus of the long term period is the
expected rain (potentially heavy especially along the coastal
plains) Tuesday into Wednesday. Late this week, the forecast is
low confidence as there will be two lows interacting, one from
the SE u.S., and one digging in from the nw. Depending on if or
which one of these lows becomes dominant, we could see a period
of unsettled weather either Friday or Saturday.

Details: the next low currently over the deep south, will
continue to very slowly progress northeast, reaching the mid
atlantic by mid week. Timing has changed a bit as models are
coming into better agreement of both the rain moving in earlier
(during the day Tuesday), and a dry slot developing and bringing
an end to the rain quicker (as early as Wednesday morning for
locations near and south of philly).

Due to the slow progression of the low and low level onshore
flow, there is some concern of heavy rain, primarily Tuesday
night. Precipitable water values are 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, on the order of 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.

Once that low lifts northeast away from our region by Thursday,
the forecast is a bit more muddled. Yesterday, it looked as if
we would have a brief period of high pressure, followed by a
cold front sweeping through on Saturday. Now however, models are
split on the overall pattern after Thursday. The biggest
challenge is figuring out how a short wave trough in the
southeast on Friday will interact with the main upper level
trough over the north central u.S., and the implications with
the surface pattern. Some models with the latest runs are
depicting this trough, and the associated surface low, becoming
the dominant low, resulting in a coastal low system for us on
Friday. While other models continue to depict the northern tier
trough and surface low being the dominant feature resulting in
only a brief period of rain with the cold front on Saturday. At
this point I stayed close to the previous forecast as there
isn't a clear signal one way or the other how this will develop.

Aviation 19z Sunday through Friday
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

Rest of this afternoon...VFR with some high clouds. Light and
variable winds or locally west or northwest less than 10 knots. A
sea bay breeze resulting in a southeasterly wind at acy and ilg, and
this should reach miv into early this evening. For phl, light enough
flow is resulting in a more south-southeast (light) surface wind
direction however this may turn more south-southwest for a time.

Tonight...VFR. Winds quickly becoming light and variable to locally

Monday...VFR. Light and variable or calms winds, becoming south-
southeast 5-10 knots mainly from late morning through the


Monday night... MostlyVFR conditions are expected. There is a chance
that MVFR ceilings could move in from the south very late. Winds
will be light and variable for much of the period. High confidence
on most of the forecast except the timing of the MVFR ceilings, if
they come at all during this period.

Tuesday through Wednesday... MVFR and even localized ifr conditions
will be possible especially on Tuesday night into Wednesday morning
as periods of rain are likely across the region. Easterly wind gusts
up to 20 kt are possible Tuesday night into Wednesday. Otherwise,
generally light winds (less than 10 kt) are expected. Moderate
confidence on flight categories, but low confidence on the timing of
any flight category changes.

Thursday and Friday... Expect mostly conditions improving toVFR,
though there remains a slight chance that rain and low clouds could
lower conditions to MVFR at times. Wind could be starting out
westerly, but shifting to southeasterly. Low confidence on flight
categories and wind.

The conditions are expected to remain below small craft advisory
criteria through Monday. A south to southeast flow may turn west to
northwest (light) later tonight, then a more dominant southeasterly
flow occurs on Monday. There will be some mainly nearshore
enhancement to the winds (gusts to about 15 knots) into this evening
due to a sea bay breeze, then again Monday afternoon.


Monday night... Winds and seas are expected to remain below sca

Tuesday and Wednesday... Easterly and southeasterly winds increase to
15-20 kt with gusts up to 25 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.

Wednesday night and Thursday... Winds shift to northwesterly and
subsequently 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... Depending on if a coastal low develops, we may see
increasing southeasterly winds. If this happens, we could once again
reach SCA criteria.

Phi watches warnings advisories
Pa... None.

Nj... None.

De... None.

Md... None.

Marine... None.

Synopsis... Johnson
near term... Gorse
short term... Gorse
long term... Johnson
aviation... Gorse johnson
marine... Gorse johnson

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
DRSD1 - Delaware Reserve, DE 25 mi144 min E 6 59°F 1029 hPa27°F
CA2 - 8571892 - Cambridge, MD 25 mi54 min 64°F 57°F1028.6 hPa (-1.3)
CPVM2 31 mi54 min 56°F 44°F
TPLM2 - Thomas Point, MD 32 mi54 min S 7 G 8 56°F 54°F1028.7 hPa (-1.3)43°F
TCBM2 - 8573364 - Tolchester Beach, MD 32 mi54 min N 5.1 G 5.1 58°F 54°F1027.8 hPa (-1.5)
APAM2 - 8575512 - Annapolis, MD 35 mi54 min 61°F 1027.3 hPa (-1.2)
44062 - Gooses Reef, MD 38 mi44 min SSW 9.7 G 12 55°F 1028.3 hPa
LWSD1 - 8557380 - Lewes, DE 38 mi54 min S 11 G 13 53°F 52°F1028.7 hPa (-1.3)
BRND1 - 8555889 - Brandywine Shoal Light, DE 39 mi54 min S 14 G 17 50°F 1029 hPa (-1.4)
FSNM2 44 mi54 min ESE 8 G 8.9 60°F 1027.2 hPa (-1.4)
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 44 mi54 min ESE 8 G 8.9 60°F 1027.5 hPa (-1.5)
COVM2 - 8577018 - Cove Point LNG Pier, MD 44 mi54 min S 14 G 16 54°F 1028.4 hPa (-1.5)
CHCM2 - 8573927 - Chesapeake City, MD 45 mi54 min W 5.1 G 8 63°F 53°F1027.9 hPa (-1.6)
CMAN4 - 8536110 - Cape May, NJ 47 mi54 min SSE 11 G 13 51°F 50°F1028.2 hPa (-1.3)
BISM2 - 8571421 - Bishops Head, MD 47 mi54 min SSE 16 G 18 56°F 62°F1028.5 hPa (-1.4)
BSLM2 - Chesapeake Bay, MD 47 mi144 min SSE 8 64°F 1028 hPa39°F
BLTM2 - 8574680 - Baltimore, MD 48 mi54 min S 5.1 G 8 62°F 53°F1027.1 hPa (-1.5)
RDYD1 - 8551910 - Reedy Point, DE 49 mi54 min 65°F 51°F1027.4 hPa (-1.7)

Wind History for Cambridge, MD
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1 day
2 days

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Easton / Newman Field, MD14 mi2.1 hrsSSE 910.00 miPartly Cloudy68°F35°F30%1029.1 hPa

Wind History from ESN (wind in knots)
Last 24hrNW6CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmE5NE3E3SE7SE5SW6W4SE9SW7
1 day agoN10
2 days agoNW17

Tide / Current Tables for Denton, Choptank River, Maryland
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Sun -- 12:33 AM EDT     2.30 feet High Tide
Sun -- 01:48 AM EDT     Moonset
Sun -- 06:17 AM EDT     Sunrise
Sun -- 06:45 AM EDT     0.55 feet Low Tide
Sun -- 12:01 PM EDT     Moonrise
Sun -- 12:58 PM EDT     3.30 feet High Tide
Sun -- 05:46 PM EDT     First Quarter
Sun -- 07:47 PM EDT     Sunset
Sun -- 08:39 PM EDT     0.65 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Tide / Current Tables for Greensboro, Choptank River, Maryland
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Sun -- 01:38 AM EDT     2.64 feet High Tide
Sun -- 01:48 AM EDT     Moonset
Sun -- 06:16 AM EDT     Sunrise
Sun -- 07:31 AM EDT     0.63 feet Low Tide
Sun -- 12:00 PM EDT     Moonrise
Sun -- 02:03 PM EDT     3.79 feet High Tide
Sun -- 05:46 PM EDT     First Quarter
Sun -- 07:47 PM EDT     Sunset
Sun -- 09:25 PM EDT     0.74 feet Low Tide
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 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 (17,4,5,8)
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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.