Thursday, March30, 2017

Marine Weather and Tides
Slaughter Beach, DE

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.
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Sunrise 6:46AMSunset 7:25PM Thursday March 30, 2017 8:29 PM EDT (00:29 UTC) Moonrise 7:41AMMoonset 9:31PM Illumination 13% Phase: Waxing Crescent; Moon at 3 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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ANZ431 Delaware Bay Waters South Of East Point Nj To Slaughter Beach De- 625 Pm Edt Thu Mar 30 2017
.small craft advisory in effect from Friday morning through Friday evening...
Tonight..SE winds 5 to 10 kt...becoming E 10 to 15 kt with gusts up to 20 kt late. Seas 2 to 3 ft. A slight chance of rain early this evening. A chance of rain late this evening and early morning...then rain likely late. Areas of fog late. Vsby 1 to 3 nm late.
Fri..SE winds 15 to 20 kt. Gusts up to 25 kt... Increasing to 30 kt in the afternoon. Seas 3 to 4 ft. Periods of rain. Areas of fog. Vsby 1 to 3 nm.
Fri night..SE winds around 15 kt...becoming W after midnight. Gusts up to 25 kt. Seas 3 to 4 ft. Rain likely until early morning...then a chance of rain late. Areas of fog. Vsby 1 to 3 nm.
Sat..NW winds 15 to 20 kt with gusts up to 25 kt. Seas 3 to 4 ft. Areas of fog early in the morning with vsby 1 to 3 nm.
Sat night..N winds 10 to 15 kt. Seas 2 to 3 ft.
Sun..NW winds around 10 kt. Seas 1 to 2 ft.
Sun night..W winds 5 to 10 kt...becoming S after midnight. Seas 1 to 2 ft.
Mon..SE winds 10 to 15 kt. Seas 2 to 3 ft. A chance of rain in the afternoon.
Mon night..SE winds around 15 kt. Seas 3 to 4 ft. Rain likely.
Tue..SE winds 15 to 20 kt. Seas 3 to 4 ft. Rain likely.
Tue night..N winds 10 to 15 kt. Seas around 3 ft. Showers likely...mainly in the evening.
ANZ400 625 Pm Edt Thu Mar 30 2017
Synopsis for the coastal waters from sandy hook nj to fenwick island de and for delaware bay.. Low pressure in the central plains will progress into the ohio valley Friday morning, then redevelop in the mid-atlantic Friday evening before moving offshore Saturday. High pressure will build into the east Sunday and Monday. Another surface low will move from the mid-south to the eastern u.s. Early next week. After brief high pressure returns midweek, another system looks to affect the eastern seaboard to close out the week.

7 Day Forecast for Marine Location Near Slaughter Beach, DE
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location: 38.95, -75.31     debug

Area Discussion for - Philadelphia/Mount Holly, PA
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Fxus61 kphi 302354
area forecast discussion
national weather service mount holly nj
754 pm edt Thu mar 30 2017

Low pressure in the central plains will progress into the ohio
valley Friday morning, then redevelop in the mid-atlantic Friday
evening before moving offshore Saturday. High pressure will build
into the east Sunday and Monday. Another surface low will move from
the mid-south to the eastern u.S. Early next week. After brief high
pressure returns midweek, another system looks to affect the eastern
seaboard to close out the week.

Near term /until 6 am Friday morning/
High pressure centered over central nj will continue to drift
offshore this evening. Meanwhile, low pressure moving into the great
lakes will continue to develop as it tracks east, and will approach
the tn/oh valleys by daybreak Friday.

Dew points are coming up quickly. Thus showers moving in from
the west are more apt to result in precipitation reaching the
ground than previously forecast. Therefore, increased pops
through the evening hours. In addition, isolated thunderstorms
have developed and persisted over central pa. Mesoanalysis shows
meager elevated instability over this area, with likely
negligible elevated instability as you move into SE pa. Still
radar trends show the storms continuing to progress east, so
added a mention of slight chance of thunderstorms to far SE pa
through the next few hours to account for any storms that
propagate into our region.

For all but the poconos, expecting rain. For the poconos, precip may
briefly start out as rain, but as the high moves offshore, enough
cold air at the surface will filter down to result in a brief period
of sleet/freezing rain, and then rain/freezing rain. NAM continues
to be the coldest of the solutions, and will follow suit. Think the
coldest of the air will be concentrated in monroe county, and went
ahead and issued a freezing rain advisory for monroe county starting
late tonight. By daybreak, a light glaze of ice will be possible.

For sussex and carbon counties, do not think temperatures will
be cold enough for widespread wintry precip, so left those
counties out of the advisory. But some sleet/freezing rain is
possible, especially towards daybreak Friday, and mainly at
higher elevations.

Otherwise, periods of mainly rain will overspread the region late
tonight and into Friday morning as the warm front lifts north of the
region. Total rainfall by daybreak should be less than 1/4".

Short term /6 am Friday morning through Friday night/
On Friday, low pressure mainly over the oh valley will lift to the
northeast. With deep upper trough and strong h5 low digging in
behind it, a secondary low looks to develop somewhere over the mid-
atlantic, and that low will lift to the northeast, impacting the mid-
atlantic and northeast portions of the country late Friday and
Friday evening. 45-55 kt LLJ will slide along the coast in the
afternoon/evening as well, helping to enhance the precip over
the region. With deep onshore flow, pwats will be around 1.25",
and we can expect periods of moderate to locally heavy rain
starting Friday afternoon.

For monroe county, enough cold air will remain to keep surface temps
at 31-33f. Can expect freezing rain to continue, but as the rain
gets heavier, it may be tough for efficient ice accretion, since
temperatures will be marginal. Will run the freezing rain advisory
through the day Friday and into Friday night, but think ice
accretion during the timing of the advisory should remain 1/4" or
less. Travel may be treacherous, especially on untreated surfaces.

Rain tapers off from SW to NE Friday evening, and the heaviest of
the rain should end after midnight Friday night. Between 1-2" of
liquid QPF is likely to fall, and this may result in poor drainage
flooding in urban areas.

Long term /Saturday through Thursday/
By 12z Saturday, the surface low making for a wet close to the week
will be moving offshore the mid-atlantic region. However, timing
differences have developed regarding the low's progression, with the
12z cmc in particular rather sluggish with its progression away from
the region. The 12z NAM is also trending on the slow side of the
model suite, with the 12z GFS a fast outlier. Given that consensus
is beginning to cluster toward the NAM and away from the gfs
solutions, think keeping some pops/thicker cloud cover around on
Saturday is a good idea. By this point, most of the precipitation
should be showery and primarily confined to the north of the mason-
dixon line. Higher-resolution simulations continue to suggest a
prolonged period of near-freezing temperatures in the southern
poconos and have included a slight chance of sleet for the highest
elevations early on Saturday in this area. If the warm nose (which
remains present through the duration of the system owing to the
cyclonic rotation of warm air advection to the north side of the
low) is stronger than forecast and temperatures at the surface are
colder than progged (the trend of this certainly being downward in
the past couple of days), then freezing rain may remain a concern
into the morning hours Saturday. However, precipitation coverage
will be on the wane during the day as the system moves away from the
region, so any societal impacts should be minimal by this point.

Two days ago, mexmos was producing temperatures about 10 degrees
higher than it is now for the CWA on Saturday. With the increased
cloud cover expected versus earlier forecasts, think the effects of
downsloping (warming) may be mitigated to some degree. Continued to
trend at or below guidance for temperatures on Saturday, with highs
a few degrees below seasonal averages.

Northwest upper-level flow sets in to close out the weekend as a
broad surface high builds into the eastern u.S. Temperatures will
warm as cloud cover decreases and subtle downsloping continues on
Sunday, with MAX temperatures about 10 degrees warmer than those
forecast for Saturday. Monday should see similar temperatures, but
am a bit concerned temperatures may struggle a little, as cloud
cover is expected to increase during the day.

The next southern-stream system is set to impact the east coast
Monday night through Tuesday night. A potent vorticity maximum will
progress from the southwest u.S. And adjacent northwest mexico on
Sunday to the mid-south by 00z Tuesday. As it does so, the shortwave
trough acquires a negative tilt as it lifts northeastward.

Substantial upper-level divergence downstream of the vort MAX will
promote yet another prolonged period of strong/deep ascent from the
ohio/tennessee valleys eastward to the mid-atlantic. A 50-60 kt low-
level jet will advect warm/moist air from the gulf of mexico into
much of the eastern u.S. Low-level convergence at the nose of the
jet along a zonally-oriented baroclinic zone will produce widespread
moderate to heavy precipitation along and northeast of the low's
track. The track of this low remains uncertain, as there is wide
variability among the deterministic guidance, in large part owing to
the projected degree of interaction with the polar jet and its
associated perturbations. Nevertheless, the 12z GFS has had severe
run-to-run continuity issues the past couple of days, with the 24-hr
differences in surface low placement and midlevel amplification
providing zero confidence in its reliability during this period.

Though the 12z cmc/ecmwf have shown quite a bit of variability as
well, their solutions have been more stable overall. As such, a
track near or just south of the northern mid-atlantic looks most
likely at this point. As such, the pronounced QPF they produce in
our region (1-2+ inches of QPF Monday night to Tuesday night) looks
plausible, particularly given the subtropical moisture fetch and the
synoptically favorable pattern. Hydrological concerns will likely be
enhanced with this system, at least if the heavy precipitation
expected to precede this system verifies. Although there is a remote
chance of a wintry mix in the southern poconos with this system,
think the odds are to slim to mention at this point, particularly
given the large uncertainty with the evolution of the system.

Similar reasoning precludes me from adding thunder to the grids (at
least in the far southern cwa), though this would certainly be
possible if the more northern model-simulated tracks are accurate.

Brief ridging intervenes on Wednesday, with temperatures near
seasonal averages.

Deterministic models are hinting at a northern-stream system
affecting the region late next week, but are widely variable with
timing, track, and resultant impact on our area. A relatively
consistent characteristic of this next system is its much warmer
look for the area, which suggests convection is more of a
possibility. However, given the large spread evident in ensemble
output, nowhere close to getting that specific at this juncture.

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

Vfr conditions should continue through the next few hours. By
03z, showers and areas of rain will begin moving into the
region. As a result, conditions will begin to deteriorate,
first to MVFR, then to ifr between 06 and 12z. A prolonged
period of ifr and lower conditions is expected through the day
on Friday with periods of moderate to heavy rain.

Winds will be shifting from southerly/southeasterly now to
easterly around 06z. Wind speeds are expected to increase from
around 10kt now to 10-15 kt on Friday.

There is a chance for llws along the coast (including kacy and
kmiv) as low level easterly flow increases after 18z on Friday.


Friday night and Saturday... Gradually improving cigs/vsbys with
vfr likely by Saturday afternoon. East/northeast winds
transitioning to north or northwest 10-15 kts with gusts to 25
kts, especially near the coast. Confidence average.

Saturday night through Sunday night...VFR. North/northwest winds
around 10 kts switching to a more southerly direction by Sunday
night. Confidence above average.

Monday... Increasing cloudiness with southeast winds increasing to 10
to 20 kts during the afternoon. MostlyVFR, but sub-vfr conditions
possible late. Confidence below average.

Monday night and Tuesday... MVFR/ifr conditions with rain likely.

General east winds 10 to 15 kts with higher gusts near the coast.

Confidence low.

Quiet conditions tonight, but then winds/seas ramp up from S to N as
a warm front lifts through the waters late tonight, and then
conditions deteriorate even more on Friday afternoon as low
pressure, aided by a 45-55 kt llj, tracks along the coast.

Small craft advisory conditions develop on southern waters Friday
morning. As the low lifts north, it will intensify over northern
ocean waters. Have issued a gale warning for the northern nj ocean
waters for 35 kt gusts Friday afternoon/evening.


Saturday... Advisory winds/seas likely with gale-force northwest
gusts possible off the new jersey coast. Showers possible,
especially in the morning.

Saturday night and Sunday... Winds rapidly diminish, but seas will
remain elevated.

Sunday night and Monday... Sub-advisory winds/seas expected.

Monday night and Tuesday... Small craft advisory conditions possible.

Rain and restrictions in visibility are likely, especially on

One to two inches of rain has been inserted into the hydrologic
models today, mainly falling Friday and Friday night. The snow has
melted across the raritan basin and mostly melted across the
passaic basin. Snow remains on the ground across the headwaters
of the delaware river. Swe's in this area are still running
1.00 to 1.50 inches in spots, but luckily the snow has been
melting. Swe's were higher a week ago.

Potential flooding can be broken down into three different
categories... Low lying/poor drainage... Smaller creeks and streams,
larger rivers. With some periods of moderate to heavy rain expected,
poor drainage and low lying flooding will develop first where the
rain falls. This will happen during the day on Friday into Friday
night. The runoff will make it to smaller creeks and streams causing
rises and possible flooding Friday afternoon, Friday night, and into
early Saturday. Some larger river flooding is possible beginning
Saturday and could persist across a few spots into next week.

In terms of river flooding... For the delaware river, 5 to 10 foot
rises could be expected depending on location through the weekend.

The combination of snowmelt and rainfall is yielding 10 ft rises at
riegelsville. This would be enough to bring water levels into action
stage late Saturday night into Sunday. Elsewhere along the river,
action stage is approached, but not exceeded.

Across the passaic basin, both boonton below and pine brook hit
action stage on Sunday. Portions of the passaic won't crest until
next week. That being said, further rises could be expected into
Monday and Tuesday.

The millstone river in the raritan basin is forecast to hit action
stage Saturday. Water levels reaching minor flooding can't be ruled
out here. Expect causeways to be closed.

Further south in nj, the rancocas river at pemberton is forecast to
approach action stage on Sunday.

Currently no forecast points in pa are hitting action stage levels
(or higher).

Tides/coastal flooding
Although astronomical tides are diminishing now that we are past the
new moon, the threat of minor tidal flooding along the nj and de
coasts will increase the next 24 to 36 hours as surface low
pressure rides across the mason-dixon line late Friday and off
the nj coast early on Saturday.

In response to the low's track, an onshore flow will increase
tonight, intensify tomorrow, and peak across the northern nj coast.

Forecast tidal levels from the etss continue to be higher than most
other guidance. We think that this is overdone, especially tonight
with the lighter SE winds. Still, some spotty minor can't be ruled
out along the coast and across de bay.

The high tide of most concern remains Friday evening and Friday
night, particularly along the northern and central new jersey shore
where the strongest winds will occur. By this tide cycle, it will
take a surge of 0.8 to 1.0 feet to reach minor flooding thresholds.

And we think this is likely. The magnitude of the surge will be
dependent on how quickly the onshore flow develops and how strong it
will be. The etss, which we think is running hot, is forecasting
moderate flooding at sandy hook Friday night. So keep abreast of the

At this time, none of the guidance is reaching the minor flooding
threshold along the eastern shore of md on Friday night, but
guidance is suggesting action stage which could yield some spotty

Phi watches/warnings/advisories
Pa... Freezing rain advisory from 2 am Friday to 6 am edt Saturday
for paz055.

Nj... None.

De... None.

Md... None.

Marine... Small craft advisory from 6 am Friday to 6 am edt Saturday for

Gale warning from 2 pm Friday to 2 am edt Saturday for anz450-

Small craft advisory from 11 am Friday to 6 am edt Saturday
for anz454-455.

Small craft advisory from 11 am to 8 pm edt Friday for anz430-

Synopsis... Cms
near term... Johnson/mps
short term... Mps
long term... Cms
aviation... Cms/johnson/mps
marine... Cms/mps

tides/coastal flooding...

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
DRSD1 - Delaware Reserve, DE 12 mi75 min ESE 5.1 44°F 1021 hPa36°F
LWSD1 - 8557380 - Lewes, DE 15 mi42 min SSE 8.9 G 14 44°F 47°F1020.9 hPa
CMAN4 - 8536110 - Cape May, NJ 19 mi42 min SE 9.9 G 13 43°F 46°F1020.8 hPa
SJSN4 - 8537121 - Ship John Shoal, NJ 25 mi42 min SE 16 G 18 44°F 46°F1020.5 hPa
RDYD1 - 8551910 - Reedy Point, DE 44 mi42 min 44°F 46°F1020 hPa
OCIM2 - 8570283 - Ocean City Inlet, MD 45 mi42 min SE 8.9 G 15 44°F 50°F1021.1 hPa
DELD1 - 8551762 - Delaware City, DE 46 mi42 min SSE 8.9 G 13 44°F 47°F1020.4 hPa
CA2 - 8571892 - Cambridge, MD 48 mi42 min SE 7 G 14 48°F 51°F1018.8 hPa
CHCM2 - 8573927 - Chesapeake City, MD 48 mi42 min ESE 6 G 8.9 45°F 48°F1019.6 hPa

Wind History for Brandywine Shoal Light, DE
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1 day
2 days

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Dover Air Force Base, DE16 mi32 minESE 1010.00 miOvercast44°F38°F80%1020.6 hPa
Georgetown - Delaware Coastal Airport, DE17 mi36 minSE 910.00 miOvercast45°F33°F63%1020.5 hPa
Wildwood, Cape May County Airport, NJ22 mi34 minSE 910.00 miOvercast43°F34°F71%1021.8 hPa

Wind History from DOV (wind in knots)
1 day agoN10N10N10N9N7N7NW4NW5N5NW9N10N11N15
2 days agoCalmSE4SE4S7S5S9S7S7S7S3S3S4N5CalmSW15

Tide / Current Tables for Mispillion River entrance, Delaware Bay, Delaware
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Mispillion River entrance
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Thu -- 05:44 AM EDT     -0.71 feet Low Tide
Thu -- 06:48 AM EDT     Sunrise
Thu -- 08:40 AM EDT     Moonrise
Thu -- 11:34 AM EDT     5.21 feet High Tide
Thu -- 05:58 PM EDT     -0.60 feet Low Tide
Thu -- 07:23 PM EDT     Sunset
Thu -- 10:30 PM EDT     Moonset
Thu -- 11:56 PM EDT     5.80 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Tide / Current Tables for Delaware Bay Entrance, Delaware Current
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Delaware Bay Entrance
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Thu -- 12:11 AM EDT     -0.00 knots Slack
Thu -- 03:46 AM EDT     -1.86 knots Max Ebb
Thu -- 06:37 AM EDT     0.00 knots Slack
Thu -- 06:47 AM EDT     Sunrise
Thu -- 08:40 AM EDT     Moonrise
Thu -- 09:28 AM EDT     1.84 knots Max Flood
Thu -- 12:35 PM EDT     -0.00 knots Slack
Thu -- 04:00 PM EDT     -1.72 knots Max Ebb
Thu -- 06:44 PM EDT     0.00 knots Slack
Thu -- 07:22 PM EDT     Sunset
Thu -- 09:44 PM EDT     2.00 knots Max Flood
Thu -- 10:29 PM EDT     Moonset
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 (20,4,5,8)
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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.