Tuesday, March28, 2017 L-36.com

Marine Weather and Tides
Colwyn, PA

Version 3.4
What's New / NOTES
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 6:47AMSunset 7:22PM Tuesday March 28, 2017 9:28 PM EDT (01:28 UTC) Moonrise 6:22AMMoonset 7:10PM Illumination 2% Phase: Waxing Crescent; Moon at 2 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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ANZ430 Delaware Bay Waters North Of East Point Nj To Slaughter Beach De- 647 Pm Edt Tue Mar 28 2017
Tonight..N winds 5 to 10 kt...increasing to nw 10 to 15 kt with gusts up to 20 kt late. Seas 1 foot or less... Then 1 to 2 ft early this evening. Showers likely with isolated tstms early this evening...then a chance of showers late this evening. Patchy fog. Vsby 1 to 3 nm.
Wed..NW winds 10 to 15 kt. Seas 1 to 2 ft.
Wed night..N winds around 10 kt. Seas 1 to 2 ft.
Thu..NE winds 5 to 10 kt...becoming se in the afternoon. Seas 1 to 2 ft.
Thu night..SE winds 5 to 10 kt. Seas 1 to 2 ft. A chance of rain.
Fri..SE winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Rain.
Fri night..S winds 10 to 15 kt with gusts up to 20 kt... Becoming se 5 to 10 kt after midnight. Seas 2 to 3 ft. Rain.
Sat..N winds 5 to 10 kt. Seas 1 to 2 ft. Rain likely in the morning.
Sat night..N winds 5 to 10 kt. Seas 1 to 2 ft.
Sun..NW winds 5 to 10 kt. Seas 1 to 2 ft.
Sun night..NW winds around 5 kt. Seas 1 to 2 ft. Winds and waves higher in and near tstms.
ANZ400 647 Pm Edt Tue Mar 28 2017
Synopsis for the coastal waters from sandy hook nj to fenwick island de and for delaware bay.. Surface low pressure will move east from the mid-atlantic region into the open atlantic tomorrow. Canadian high pressure builds into the northeast Wednesday and Thursday. Low pressure develops in the central u.s. On Thursday, moves east into the mid-atlantic on Friday, and progresses offshore Saturday. High pressure returns to the area by late in the weekend. Another surface low may affect the region by the middle of next week.

7 Day Forecast for Marine Location Near Colwyn , PA
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location: 39.9, -75.21     debug

Area Discussion for - Philadelphia/Mount Holly, PA
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Fxus61 kphi 282337
area forecast discussion
national weather service mount holly nj
737 pm edt Tue mar 28 2017

Surface low pressure will move offshore of the mid-atlantic
tonight, then drift into the open atlantic tomorrow. Canadian
high pressure builds into the northeast late Wednesday and
Thursday. Low pressure develops in the central u.S. On Thursday,
moves east into the mid- atlantic on Friday, and progresses
offshore Saturday. High pressure returns to the area by late in
the weekend. Another surface low may affect the region by the
middle of next week.

Near term /until 6 am Wednesday morning/
Weak low pressure is located along a stationary front near the
mouth of the delaware bay this evening. Meanwhile, a cold front
is pushing through central ny/pa. Low pressure will lift to the
east-northeast this evening, followed by the cold front later

Areas of showers and drizzle continue across most of the area,
especially focused across eastern pennsylvania and
central/northern new jersey. Along with the rain and drizzle,
there is also some patchy fog across the area. These showers
will continue to drift eastward through this evening and begin
to dissipate later this evening as the surface low and mid-level
trough and vorticity impulse slide east of the area as well.

However, until the cold front moves through overnight and toward
daybreak, there will continue to be cloudy skies and some light

It remains possible for some isolated thunderstorms, mainly
across southern new jersey and the central/southern delmarva
where any instability could linger south of the front/low

Lows tonight will range from the mid and upper 30s across the
poconos and northern nj to the lower 40s for the rest of nj and
se pa, and in the mid to upper 40s in md/de.

Short term /6 am Wednesday morning through 6 pm Wednesday/
High pressure builds in from the north, bringing plenty of sunshine.

A slight downsloping flow will help moderate the temperatures, and
highs will top off in the mid 40s in the poconos, upper 50s across
northern nj and the lehigh valley, low 60s across central and
southern nj and SE pa, and in the mid to upper 60s in the

Long term /Wednesday night through Tuesday/
The long term period starts off quiet as a surface ridge axis
passes overhead Thursday morning. Surface flow becomes
northeasterly with time, and the cool/maritime origins of this
flow suggest Thursday may be a bit cooler than Wednesday,
especially if increasing cloudiness occurs early in the day.

This increased cloudiness would commence downstream of another
potent southern-stream vorticity maximum progressing eastward
from the central plains. Broad southerly low-level flow
amplifies downstream ridging in the eastern u.S., with
substantial warm advection in much of the midwest.

However, with the retreating surface high in eastern canada,
this is a favorable setup for cold air damming east of the
appalachians, particularly with the more southerly track of the
aforementioned vort max. As with the systems affecting the area
early this week, I think the models are overly aggressive
sweeping the baroclinic zone/associated warm front north through
the region Thursday night and Friday. Though the 12z GFS is a
bit of an outlier with the southern/slower track, the
disagreement in the midlevels between the 12z cmc/ecmwf do not
provide confidence enough to discard the GFS solution, which
would favor a somewhat colder scenario for our area (though the
gfs is itself switching winds to south way too fast in such a
setup). For temperatures, generally went somewhat below guidance
Thursday night and Friday, and my suspicion is that I am still
too warm during both periods.

The implications of this are most important for the southern
poconos and sussex county, nj, where precipitation will likely
begin Thursday night and temperatures will once again flirt with
the freezing mark. Model guidance is at least somewhat
suggestive of a wintry mix of precipitation in this region, and
thermal profiles suggest the presence of a warm nose, which may
mean that freezing rain and/or sleet would be possible. For now,
kept things simple with a mix of rain and snow in this area
(particularly with surface temperatures forecast slightly above
freezing), but later shifts may need to include mention of sleet
or freezing rain in this region. By some time on Friday,
temperatures are expected to warm here enough for precipitation
to be all rain, but given lackluster performance with models
this winter scouring out this cold air in an accurate manner,
current forecast may be overly optimistic (at least Friday

A sustained southerly low-level fetch downstream of the surface
low moving through the region on Friday brings pwats > 1.0 inch
(approaching 1.25 inches) to central/southern portions of the
cwa. With aid of upper-level jet coupling, substantial
differential cyclonic vorticity advection, and considerable low-
level isentropic ascent, widespread rain should develop on
Friday and continue through Friday night as the low approaches
the mid-atlantic coast. QPF looks quite decent, with widespread
0.5-1.5 inch totals possible (and perhaps more, if some
simulations verify). The potential for storms seems limited at
this time, given the cwa's position generally along/north of the
surface low track. However, if the warm sector is able to move
more poleward than currently forecast, convection may also be a
consideration (particularly for delmarva).

The surface low is expected to move offshore by Saturday, but
wraparound showers may still occur, particularly north of the
mason-dixon line. Only gradually lowered pops late Friday night
and Saturday given this possibility. Winds will switch to the
north, but temperatures may actually be a little warmer than
Friday's readings given greater potential for sunshine, subtle
downsloping, and boundary-layer mixing. However, not sold on the
very warm mexmos readings at this point given the origins of the
upstream surface high.

Sunday and Monday should generally be dry as upstream ridging
moves through the region. Temperatures will be near to slightly
above seasonal averages.

Another in a series of southern-stream systems is projected to
move into the ohio/tennessee valleys by early next week. With
increased large-scale ascent downstream of the attendant surface
low, precipitation will probably break out Monday night and
Tuesday across the area. This low's track would be farther to
the west, which suggests this system will be warmer, giving our
region greater potential for convection. Did not add thunder to
the grids at this point given track/timing uncertainties, but
think this is a good bet given relatively decent agreement among
the model suite. Models suggest a reinforcing system may
approach the area midweek, keeping the QPF train chugging.

Aviation /00z Wednesday through Sunday/
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

Tonight... MVFR/ifr conditions possible in showers and fog early.

Isolated thunderstorms possible early, but confidence not high
enough to warrant inclusion in the taf. Sub-vfr cigs/vsbys will
continue for much of tonight in fog after showers depart.

Improvement toVFR not until prior to daybreak Wednesday.VFR
conditions will prevail through the day Wednesday.

North- northeast winds around 5 knots are expected to become
northwest overnight, and increase through daybreak. Winds will
become gusty during the day Wednesday.


Wednesday night through Thursday night...VFR with generally
light winds. Confidence well above average.

Friday through Saturday... Sub-vfr conditions likely, with
lowered CIGS and vsbys and periods of rain. East or southeast
winds Friday around 10 kts becoming northerly and potentially
gusty on Saturday. Confidence average.

Saturday night and Sunday...VFR with north or northwest winds
around 10 kts with at least some potential for gusts to 20 kts.

Confidence average.

Vsby reductions possible in showers and fog tonight, with
improvements not until well after midnight. Unlimited vsbys expected
on Wednesday. Sub-sca conditions tonight through Wednesday, but some
gusts to 20 kt possible Wednesday morning/early afternoon, mainly on
the ocean.


Wednesday night... Marginal small craft advisory conditions
possible, especially off the new jersey coast.

Thursday and Thursday night... Sub-advisory conditions expected.

Friday through Saturday... Marginal advisory conditions possible.

Rain likely.

Saturday night and Sunday... Sub-advisory conditions expected.

Tides/coastal flooding
Though astronomical tides will be gradually diminishing through the
week now that we are past the new moon, the threat of minor tidal
flooding along the nj and de atlantic coasts increases late in the
week. This is a result of a low pressure system bringing a prolonged
period of on shore flow. The tide of most concern at this point is
the high tide on Friday evening/late Friday night. By this tide
cycle, it will take a surge of 0.8 to 1.0 feet to reach minor
flooding thresholds, which is possible but still uncertain (it
will be dependent on how quickly the on shore flow develops and
how strong it will be by then). At least one source of guidance
shows water levels reaching minor tidal flooding thresholds with
the Thursday evening/night high tide, but that seems unlikely
as the latest forecast depicts onshore flow either developing
right around or just after the time of that high tide.

Knel appears to be reading 10f too warm the past several days.

Phi watches/warnings/advisories
Pa... None.

Nj... None.

De... None.

Md... None.

Marine... None.

Synopsis... Cms
near term... Mps/robertson
short term... Mps
long term... Cms
aviation... Cms/mps/robertson
marine... Cms/mps
tides/coastal flooding...


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
PHBP1 - 8545240 - Philadelphia, PA 4 mi40 min 47°F 44°F1012.7 hPa
BDSP1 9 mi40 min 48°F 1013.2 hPa
MRCP1 - 8540433 - Marcus Hook, PA 13 mi40 min 51°F 1012.6 hPa
BDRN4 - 8539094 - Burlington, Delaware River, NJ 22 mi52 min 46°F 43°F1012.8 hPa
NBLP1 - 8548989 - Newbold, PA 29 mi40 min NNE 1 G 4.1 46°F 44°F1013.6 hPa
RDYD1 - 8551910 - Reedy Point, DE 30 mi40 min 51°F 46°F1012.6 hPa
DELD1 - 8551762 - Delaware City, DE 30 mi40 min N 7 G 8 49°F 46°F1013 hPa
CHCM2 - 8573927 - Chesapeake City, MD 41 mi40 min N 2.9 G 7 55°F 47°F1012.5 hPa
SJSN4 - 8537121 - Ship John Shoal, NJ 42 mi40 min 51°F 45°F1011.9 hPa
JCRN4 - Jacques Cousteau Reserve, NJ 47 mi58 min NNW 2.9 48°F 1012 hPa48°F

Wind History for Philadelphia, PA
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1 day
2 days

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Philadelphia, Philadelphia International Airport, PA2 mi34 minN 610.00 miOvercast49°F46°F93%1013.2 hPa
Philadelphia - Wings Field Airport, PA17 mi33 minN 010.00 miOvercast45°F44°F100%1012.9 hPa
Philadelphia, Northeast Philadelphia Airport, PA17 mi34 minNE 57.00 miOvercast48°F46°F96%1013.5 hPa
Mount Holly, South Jersey Regional Airport, NJ20 mi34 minNNE 64.00 miLight Rain Fog/Mist46°F45°F96%1013 hPa

Wind History from PHL (wind in knots)
1 day agoE11NE6E7NE6E7E6E7E7E6E5NE3SE5CalmCalmSE3S3SW8SW7SW6S5CalmE3E4Calm
2 days agoE10E11E11E10E13

Tide / Current Tables for Penrose Avenue Bridge, Schuylkill River, Pennsylvania
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Penrose Avenue Bridge
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Tue -- 02:01 AM EDT     6.45 feet High Tide
Tue -- 06:50 AM EDT     Sunrise
Tue -- 07:22 AM EDT     Moonrise
Tue -- 09:08 AM EDT     -0.09 feet Low Tide
Tue -- 02:24 PM EDT     6.44 feet High Tide
Tue -- 07:21 PM EDT     Sunset
Tue -- 08:09 PM EDT     Moonset
Tue -- 09:31 PM EDT     0.08 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Tide / Current Tables for Philadelphia, Pennsylvania Current
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Tue -- 12:01 AM EDT     1.96 knots Max Flood
Tue -- 03:19 AM EDT     -0.00 knots Slack
Tue -- 06:50 AM EDT     Sunrise
Tue -- 06:55 AM EDT     -2.19 knots Max Ebb
Tue -- 07:22 AM EDT     Moonrise
Tue -- 10:24 AM EDT     0.01 knots Slack
Tue -- 12:22 PM EDT     2.12 knots Max Flood
Tue -- 03:38 PM EDT     -0.01 knots Slack
Tue -- 07:08 PM EDT     -2.17 knots Max Ebb
Tue -- 07:21 PM EDT     Sunset
Tue -- 08:09 PM EDT     Moonset
Tue -- 10:47 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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Weather Map
IR Satellite Image from GEOS

GOES Local Image of Mid-Atlantic    EDIT

Wind Forecast for Philadelphia/Mount Holly, PA (21,6,7,8)
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Ground Weather Radar Station Philadelphia, PA
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weather_mapweather_map weather_map

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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.