Thursday, January24, 2019 L-36.com


Marine Weather and Tides
Choptank, MD

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:14AMSunset 5:17PM Thursday January 24, 2019 5:22 AM EST (10:22 UTC) Moonrise 9:38PMMoonset 9:49AM Illumination 87% Phase: Waning Gibbous; Moon at 18 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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ANZ541 Choptank River To Cambridge Md And The Little Choptank River- 340 Am Est Thu Jan 24 2019
.gale warning in effect through this afternoon...
.small craft advisory in effect from this evening through late tonight...
Rest of the overnight..S winds 20 kt with gusts to 40 kt. Waves 2 ft...except around 4 ft near the mouth of the choptank. Rain.
Today..S winds 20 to 25 kt with gusts to 50 kt... Becoming nw 15 to 20 kt with gusts to 35 kt in the afternoon. Waves 4 ft. Rain. Vsby 1 nm or less.
Tonight..NW winds 15 to 20 kt with gusts to 30 kt... Becoming W 10 kt with gusts to 20 kt late. Waves 4 ft... Subsiding to 2 ft after midnight.
Fri..W winds 10 to 15 kt with gusts to 30 kt. Waves 1 to 2 ft.
Fri night..NW winds 10 to 15 kt. Gusts up to 25 kt in the evening. Waves 1 to 2 ft.
Sat..NE winds 5 to 10 kt...becoming S in the afternoon. Gusts up to 20 kt. Waves 1 ft.
Sat night..S winds 10 to 15 kt with gusts to 20 kt. Waves 1 to 2 ft.
Sun..W winds 5 to 10 kt. Waves 1 ft.
Mon..SW winds 5 kt...becoming se. Waves 1 ft.
ANZ500 340 Am Est Thu Jan 24 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front over the ohio valley will cross the waters this afternoon as low pressure passes through the region. A reinforcing front will push through the waters on Friday, with high pressure transiting the area through the weekend. Small craft advisories are likely Friday and Friday night, and may be required Saturday night and Sunday.


7 Day Forecast for Marine Location Near Choptank, MD
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location: 38.68, -75.95     debug


Area Discussion for - Philadelphia/Mount Holly, PA
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Fxus61 kphi 240702
afdphi
area forecast discussion
national weather service mount holly nj
202 am est Thu jan 24 2019

Synopsis
Low pressure will pass through the great lakes and into ontario and
quebec tonight. Areas of rain, some heavy, will develop late tonight
and particularly tomorrow ahead of a cold frontal passage later
tomorrow. High pressure and cooler but drier weather builds in
for Friday and Saturday. A cold front will cross the region
Sunday associated with a low pressure to our north which may
bring some snow showers. Another period of unsettled weather is
possible early next week, but its evolution is uncertain.

Near term until 6 am this morning
Forecast for the next few hours is quite challenging, as a warm
front lifts north through the area. Temperatures are surging
into the 50s generally along and south of the i-276 i-195
corridors and remain stuck in the 30s to around 40 north of the
i-78 corridor. If anything, models are too slow with the front's
northward progress, which is certainly unusual when considering
the typical systematic bias models exhibit. Not so unusual is
the models are too weak with both the temp and dew point
gradients, so the forecast temperatures are generally too cool
south of the front and too warm north of the front. Modified the
forecast the rest of the night in an attempt to account for
these discrepancies, though this will be a matter of chasing
observations for the most part given the fairly poor performance
of the models to this point.

Another issue is the rather light rain and drizzle that is
developing near the warm front, which is generally overdone with
some hi-res guidance and not forecast by other models. A
consensus approach to pops wx grids seems appropriate in this
regime. This greatly reduced pops for the next 3-5 hours
southeast of the fall line (where precipitation will be light
and may not be measurable some hours), and slowed the onset of
higher pops in the poconos, where rain still remains rather
spotty light as well (though with more widespread coverage than
farther southeast).

Expecting precipitation to pick up after 09z, especially
near northwest of the fall line given hi-res model consensus.

Will continue to monitor and update the forecast as the latest
hi-res guidance comes in.

Finally, updated the wind forecast based on surface
observations. This required increasing the winds gusts farther
northwest into the urban corridor but slightly reducing the
magnitudes of the gusts to the southeast given the past few
hours of observations in DELMARVA and southern new jersey. Gusts
are predominantly below 40 mph (well below advisory criteria),
though an isolated gust to 45 mph is possible right near the
coast. The magnitude of the low-level jet is allowing even
inefficient mixing to provide breezy conditions, but the low-
level thermal profile is not particularly favorable for stronger
mixing gusts.

Short term 6 am this morning through 6 pm today
Forecast is mostly on track for a heavy rain strong wind event
on Thursday. Made some minor edits to the forecast, but the
general setup looks similar to past forecasts.

A strong surface low in quebec will lift northeast today, with a
south-southwest extending cold front sweeping through the
northeast and mid-atlantic during the day. Very strong low-level
warm moist advection will occur in advance of the front, with
sustained deep large-scale lift aided by the presence of the
right-entrance region of an anticyclonic and intense (180+-kt)
250-mb jet streak and differential cyclonic vorticity advection
downstream of a deep strong midlevel trough reaching the
appalachians by 12z. With an unusually moist troposphere (pws
~1.5 inches by mid-morning; off-the-charts climatologically), a
period of moderate to heavy rain appears probable across the
whole area this morning into early afternoon. Hi-res models
continue to simulate, nearly universally, a fairly intense,
frontally-forced line of convection embedded within the broader
shield of rain. Instability looks meager at best, so lightning
will be scarce and possibly nonexistent.

The bigger story will be the heavy rain rates within the shield
of rain, particularly with the aforementioned frontally-forced
line. With consensus model QPF generally 1-1.5 inches (slightly
higher north of i-78), suspect most of this rain will occur in
a 1-3 hour period. Given the cold ground, wet antecedent
conditions, and responses to previous events (even longer-
duration lighter-rain events), urban and small-stream flooding
looks probable within the current flood watch. Cannot rule out
an instance or two of flash flooding, given the convective look
to the precipitation just in advance of the front. The primary
limitation is the progressive nature of the precipitation line.

Given that precipitation is struggling to develop well
downstream of the front so far tonight, the progressive nature
of the front may preclude a more widespread flood threat.

Nevertheless, the potential certainly exists for some localized
flooding, especially where the heaviest axis of precipitation
sets up. Should this be in the urban corridor or in especially
sensitive areas to the northwest of philadelphia, think that a
few instances of flooding will occur.

The other issue will be the winds, both in advance of the front
and with its passage. Mixing will continue downstream of the
front this morning, with models hinting at widespread gusts
35-45 mph with localized instances higher than that. This looks
a little overdone (hi-res models tend to do this in these
regimes), but the strength of the low-level jet (50-80+ kts)
certainly suggests the possibility of some stronger wind gusts.

My suspicion, however, is the strongest wind gusts will occur
with and just in advance of the frontally-forced line of
precipitation, with negative buoyancy effects allowing for
enhanced downward momentum transfer. Whatever the causal
mechanisms, strong wind gusts for a time are a good bet, with
the current wind advisory unchanged at this time.

Temperatures will continue to surge in advance of the
precipitation, but the front will move through during the
afternoon, with temps dews falling thereafter. Winds will switch
to the northwest and may continue to be gusty for a time.

Precipitation should shut off quickly upstream of the front, but
may linger in the far northern cwa, where switchover to some
snow showers is possible.

Used a heavy dose of hi-res model guidance for temperatures
through tomorrow, as statistical bias-corrected guidance is
expected to verify poorly in such a rapidly-changing
meteorological regime.

Long term tonight through Wednesday
Overview...

most if not all of this period will be driven by the presence of a
broad, deep trough over the central and eastern us. The axis of the
longwave trough will move little for several days, but the flow within
the trough is progressive and will allow for multiple shortwaves to
rotate through it. The tracks and timing of these features will dictate
our precipitation opportunities for this weekend and early next week.

With the depth of the trough, appears we are largely shut out from any
southern stream moisture this period, which would favor precipitation
threats to be on the lighter side. However, given multiple northern
stream disturbances moving through, it will have to be monitored as to
whether we can tap into any of the better moisture to the south and
potentially create a larger precip event. Present indications suggest
not, but still several days away. Plenty of bitterly cold air will be
present well to our north over this stretch, but despite the troughing
pattern the core of the cold remains largely bottled up in canada.

Thus, temperatures should not stray too far from normal for most of
this period.

Dailies...

Friday-Saturday... This looks like the quiet portion of the long term.

Cold front will be well offshore by Friday morning with high pressure
gradually building in from the west. Temperatures trend cooler but not
especially cold. A shortwave passing through the great lakes and into
the northeast on Friday is largely moisture starved, but could produce
some light snow showers in western and northwestern areas.

Saturday night-Sunday... First potential unsettled period of the long
term comes here as a potent shortwave and closed h5 low dives into
ontario. However, this system remains well to our north, and appears
unlikely to connect with better moisture well to our south and east.

This means the most likely outcome is just some scattered snow showers
late Saturday night and Sunday. Winds turn out of the south before a
cold frontal passage late Sunday, so it is possible these showers may
mix with rain in southern areas given decent WAA ahead of the front.

Sunday night-Monday... High pressure likely builds in to our north, at
least briefly. Guidance does begin to diverge quite a bit by this
period, not surprising given models often struggle with small, fast
moving features like we will be dealing with. But feel this period
should be mostly dry. A lot of spread on temperatures at this range as
baroclinicity looks strong over the east, with very cold air not far to
the north but much warmer not far south and our region likely caught in
between. Stayed close to the consensus which leaves us near average.

Monday night-Wednesday... Confidence decreases further here. Decent
agreement on a clipper low moving through the lingering trough and
approaching Monday night or Tuesday, with some discrepancies on its
exact track. We are probably in line for a precipitation event centered
around Tuesday, but several scenarios exist. This includes a warm
solution of a single parent low passing to our west, which is favored
by most of the 23.12z guidance. However, some form of coastal
redevelopment could also occur and introduce more complications, as
some of the 23.0z guidance and 23.12z ec suggested. Plenty of time to
iron this out and as usual for this range keeping details limited for
now. Drier and colder weather likely returns by Wednesday though can't
rule out some snow showers here either.

Aviation 07z Thursday through Monday
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

Rest of tonight... Deteriorating conditions to MVFR through the
remainder of the night. Rain chances increase from west-
northwest to southeast through 4 am. Some showers ahead of the
main area of rain have and will likely continue to move through
the area, likely affecting kphl, kpne, and kttn terminals. South
winds 10-15 knots initially, with higher gusts up to 30 knots
possible, especially southwest of kphl and closer to daybreak.

Winds should remain on the lighter side tonight from 5-10 knots
at krdg and kabe. Southwesterly llws is also present across the
terminals tonight, generally around 45-55 knots.

Thursday... Ifr restrictions will continue through at least early
afternoon, with rain (heavy at times). Southwesterly llws will also
continue through the morning, being the strongest at kacy.

Conditions are expected to improve rapidly during the afternoon with
the passage of a cold front.VFR is possible late into the day.

Southwest winds 10 to 20 kts with higher gusts possibly up to 40
knots before the frontal passage. Timing of the frontal passage
looks to be from 14-18z across the area from west to east. Winds
should take a more northwesterly direction after the front passes
through.

Outlook...

Thursday night... MainlyVFR with west to northwest winds around
or below 10 kts.

Friday and Saturday... MainlyVFR conditions expected. Winds
generally below 20 knots.

Saturday night through Sunday night... A cold front may bring rain
and or snow showers, thus possibly lowering visibilities and
bringing restrictions, especially at krdg and kabe.

Monday... MainlyVFR. Some MVFR possible in rain and or snow showers.

Marine
Upgraded lower delaware bay and the delaware atlantic waters to
a gale warning, given occasional gusts to 35 kts occurring at
lewes and dewey beach the past couple of hours. Winds are
decidedly lower elsewhere, so the small craft advisory continues
in these areas through 6 am.

For today... There is about a 3-6 hour window where winds may
increase to gale force across the whole area. This looks to be
within and just in advance of a band of precipitation moving
through late this morning and early this afternoon. The band of
precipitation will likely have embedded convection. This, in
particular, is troublesome because of the very strong winds
present aloft. Though low-level thermodynamic profiles are not
entirely favorable for efficient mixing, the strength of the
winds aloft suggests potential exists for a short period of
gales. Gusts may reach 40-45 kts, particularly within and near
any convection.

After the front passes by mid afternoon, winds will switch to
northwest and may gust to gale force briefly before diminishing
steadily thereafter. Advisory-level winds should continue
through the evening but will likely diminish overnight.

Seas will be quite elevated on the atlantic today, rising to 9
to 15 feet by midday before subsiding slowly thereafter. They
should remain above 5 feet through tonight, so a small craft
advisory will be required once the gale warning expires or is
canceled.

Outlook...

Friday... Advisory conditions possible, especially in the
afternoon and early evening and especially off the new jersey
coast.

Friday night through Monday... Sub-advisory winds seas expected.

Hydrology
A flood watch remains in place for late tonight through Thursday
afternoon from the lehigh valley and northwest new jersey
southeastward to the i-95 295 corridors. A cold front will move
through the area on Thursday. A round of rain, moderate to heavy at
times, is expected in advance of the front late tonight into
tomorrow morning.

Expected storm totals are generally from 1 to 1.5 inches, with
locally higher amounts possible. Normally, these totals would not be
forecast to produce much flooding. However, a number of factors
suggest an elevated threat exists...

1) antecedent wet conditions, including from the rainfall this past
weekend.

2) relatively cold soils, aided by the arctic air that spread across
the region the past couple of days.

3) the expectation of most of this rain occurring in a three-to-six
hour period. With higher rain rates expected during a portion of the
event, especially just in advance of the frontal passage on
Thursday, additional runoff will be generated, which could lead to
flooding of particularly sensitive spots (e.G., urban areas and
quickly-responding creeks and streams).

4) light to moderate rain occurring for a few hours before the
heaviest rainfall occurs, which may act to saturate soils
sufficiently for efficient runoff during the most intense rainfall.

An isolated instance of flash flooding is possible, especially if
the heaviest rainfall (and high rainfall rates) occurs along the
urban corridor or atop smaller stream creek basins that respond
rapidly to runoff.

River flooding cannot be ruled out, especially on the passaic,
rockaway, north branch rancocas, and millstone rivers, if the axis
of heaviest rainfall intersects these basins.

Phi watches warnings advisories
Pa... Flood watch through this afternoon for paz061-062-070-071-
101>106.

Nj... Flood watch through this afternoon for njz001-007>010-012>020-
026-027.

Wind advisory from 6 am this morning to noon est today for
njz013-014-020>027.

De... Flood watch through this afternoon for dez001.

Wind advisory from 6 am this morning to noon est today for
dez002>004.

Md... Flood watch through this afternoon for mdz008.

Wind advisory from 6 am this morning to noon est today for
mdz012-015-019-020.

Marine... Small craft advisory until 6 am est early this morning for
anz430-450>453.

Gale warning from 6 am this morning to 1 pm est this afternoon
for anz430-450>453.

Gale warning until 1 pm est this afternoon for anz431-454-455.

Synopsis... O'brien
near term... Cms
short term... Cms
long term... O'brien
aviation... Cms davis kruzdlo o'brien
marine... Cms kruzdlo o'brien
hydrology... Cms kruzdlo


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CA2 - 8571892 - Cambridge, MD 10 mi40 min 54°F 36°F1006.7 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 30 mi34 min S 18 G 21 43°F 1006.3 hPa
TPLM2 - Thomas Point, MD 30 mi22 min SSE 23 G 24 46°F 38°F1004.6 hPa (-5.1)46°F
BISM2 - 8571421 - Bishops Head, MD 32 mi34 min SSE 15 G 17 43°F 1006.9 hPa
CPVM2 32 mi34 min 50°F 50°F
APAM2 - 8575512 - Annapolis, MD 35 mi34 min 48°F 1004.1 hPa
SLIM2 - 8577330 - Solomons Island, MD 36 mi34 min S 16 G 18 54°F 39°F1005.2 hPa
DRSD1 - Delaware Reserve, DE 39 mi112 min SSE 12 59°F 1008 hPa55°F
TCBM2 - 8573364 - Tolchester Beach, MD 40 mi34 min S 15 G 22 55°F 34°F1004.2 hPa
BSLM2 - Chesapeake Bay, MD 41 mi112 min S 9.9 49°F 1007 hPa48°F
LWSD1 - 8557380 - Lewes, DE 45 mi34 min S 12 G 20 56°F 39°F1007.2 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 48 mi34 min SSE 14 G 17 49°F 1003.6 hPa
FSNM2 48 mi40 min S 14 G 22 51°F 1003.4 hPa
BRND1 - 8555889 - Brandywine Shoal Light, DE 49 mi34 min 1007.5 hPa
PPTM2 - 8578240 - Piney Point, MD 49 mi40 min SSE 15 G 16

Wind History for Cambridge, MD
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Easton / Newman Field, MD11 mi25 minSSE 15 G 247.00 miLight Drizzle56°F54°F93%1007.1 hPa
Cambridge-Dorchester Airport, MD11 mi42 minSSE 15 G 236.00 miFog/Mist54°F53°F100%1007.1 hPa

Wind History from CGE (wind in knots)
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1 day agoNW5N5N6
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N9NW6N7NW4CalmN63CalmCalmCalmS4SE5S7S9S6S7S5S4S5S6S6
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Tide / Current Tables for Choptank, Choptank River, Maryland
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Choptank
Click for Map
Thu -- 01:48 AM EST     -0.36 feet Low Tide
Thu -- 06:43 AM EST     1.24 feet High Tide
Thu -- 07:15 AM EST     Sunrise
Thu -- 09:49 AM EST     Moonset
Thu -- 01:25 PM EST     -0.64 feet Low Tide
Thu -- 05:16 PM EST     Sunset
Thu -- 07:22 PM EST     1.78 feet High Tide
Thu -- 09:37 PM EST     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0-0.3-0.4-0.20.30.81.21.21.10.70.3-0.1-0.4-0.6-0.6-0.30.30.91.51.81.71.51.10.6

Tide / Current Tables for Dover Bridge, Choptank River, Maryland
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Dover Bridge
Click for Map
Thu -- 02:53 AM EST     -0.38 feet Low Tide
Thu -- 07:16 AM EST     Sunrise
Thu -- 08:18 AM EST     1.31 feet High Tide
Thu -- 09:49 AM EST     Moonset
Thu -- 02:30 PM EST     -0.67 feet Low Tide
Thu -- 05:16 PM EST     Sunset
Thu -- 08:57 PM EST     1.87 feet High Tide
Thu -- 09:37 PM EST     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.50.1-0.3-0.4-0.20.20.71.11.31.20.90.5-0-0.4-0.6-0.6-0.40.10.71.31.71.91.71.3

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Disclaimer:
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.