Tuesday, March28, 2017 L-36.com


Marine Weather and Tides
Grasonville, MD

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 6:52AMSunset 7:26PM Tuesday March 28, 2017 5:35 PM EDT (21:35 UTC) Moonrise 6:27AMMoonset 7:14PM Illumination 2% Phase: Waxing Crescent; Moon at 1 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- 432 Pm Edt Tue Mar 28 2017
.small craft advisory in effect from midnight edt tonight through Wednesday afternoon...
Rest of this afternoon..S winds 5 kt. Waves less than 1 ft. Showers likely with a chance of tstms.
Tonight..N winds 5 to 10 kt with gusts to 20 kt. Waves 1 ft. A chance of showers.
Wed..N winds 10 to 15 kt with gusts to 20 kt. Waves 1 to 2 ft.
Wed night..N winds 10 kt. Waves 1 ft.
Thu..E winds 5 to 10 kt. Waves 1 ft.
Thu night..SE winds 5 to 10 kt. Waves 1 ft or less. A chance of rain.
Fri..S winds 5 to 10 kt. Waves 1 ft. Rain...then showers likely after midnight.
Sat..N winds 5 to 10 kt. Waves 1 ft. Showers likely in the morning. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 432 Pm Edt Tue Mar 28 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front is expected to cross the chesapeake bay this evening. High pressure will build into the waters for midweek, followed by a low pressure system moving towards the region on Friday. This system will exit the region Saturday. Small craft advisories are possible Thursday night through Saturday.

7 Day Forecast for Marine Location Near Grasonville, MD
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location: 38.88, -76.25     debug


Area Discussion for - Philadelphia/Mount Holly, PA
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Fxus61 kphi 282003
afdphi
area forecast discussion
national weather service mount holly nj
403 pm edt Tue mar 28 2017

Synopsis
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.

Near term /until 6 am Wednesday morning/
Weak low pressure lies along a stationary front just over the
delmarva. Meanwhile, a cold front is pushing through central ny/pa.

Low pressure will lift to the northeast this evening, followed by
the cold front later tonight.

The first area of rain is pushing northeast through northern nj and
the poconos, and patchy fog is developing in its wake. There will be
some locally dense fog, but it is not widespread enough to warrant a
dense fog advisory.

Latest hrrr indicates a secondary area of showers and possible
thunderstorms near the delmarva. This is also shown in the 12z nam
and 12z gfs. This area then lifts to the north and east through this
evening as low pressure moves off the atlantic coast. E-ne flow on
the northern side of the stationary front is keeping nj/pa stable,
and just south of the front is a warmer and more unstable airmass,
with 250-500 j/kg sb CAPE across de/md. Much higher sb CAPE values
can be found across va (1000-2000 j/kg) where storms are beginning
to develop. Would expect storms to move into the delmarva, but do
not think they will last long as they track to the north and east.

Will keep chances for thunderstorms capped at isolated.

Wave of low pressure departs early this evening, but it will take
some time for the cold front behind it to pass through the region.

It will then take even more time for northerly winds to increase
enough for drier air to filter into the region. Patchy fog will
develop this evening, and will persist until ending prior to
daybreak Wednesday.

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
delmarva.

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
morning).

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 /20z Tuesday 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. Lgt/vrb
winds this evening, becoming N 5-10 late tonight.

Outlook...

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.

Marine
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.

Outlook...

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.

Equipment
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
short term... Mps
long term... Cms
aviation... Cms/mps
marine... Cms/mps
tides/coastal flooding... Johnson
equipment... Drag


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
TPLM2 - Thomas Point, MD 10 mi35 min ENE 6 G 7 61°F 47°F56°F
CPVM2 11 mi47 min 63°F 57°F
APAM2 - 8575512 - Annapolis, MD 14 mi47 min 65°F 1009.2 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 23 mi47 min N 5.1 G 6 60°F 48°F1010.1 hPa
CA2 - 8571892 - Cambridge, MD 23 mi47 min SSW 4.1 G 6 67°F 48°F1009.2 hPa
44062 - Gooses Reef, MD 24 mi35 min S 7.8 G 7.8 53°F 48°F1010.7 hPa (-0.2)
BSLM2 - Chesapeake Bay, MD 25 mi125 min NW 7 69°F 1010 hPa55°F
FSNM2 28 mi47 min NW 7 G 8.9 66°F 1009.4 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 28 mi47 min NW 5.1 G 5.1 66°F 1009.6 hPa
BLTM2 - 8574680 - Baltimore, MD 32 mi47 min N 6 G 8.9 68°F 47°F1009.2 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 34 mi47 min SSW 7 G 8.9 58°F 1010.7 hPa
SLIM2 - 8577330 - Solomons Island, MD 40 mi47 min NW 1.9 G 4.1 63°F 49°F
WASD2 - 8594900 - Washington, DC 41 mi47 min WNW 6 G 8.9 70°F 51°F1009.3 hPa
DRSD1 - Delaware Reserve, DE 45 mi80 min N 1.9 61°F 1009 hPa58°F
BISM2 - 8571421 - Bishops Head, MD 47 mi47 min S 2.9 G 5.1 59°F 54°F1010.5 hPa

Wind History for Cambridge, MD
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Bay Bridge Field, MD8 mi60 minN 75.00 miPartly Cloudy with Haze66°F57°F73%1009.8 hPa
Easton / Newman Field, MD11 mi45 minNNW 1110.00 miMostly Cloudy72°F57°F61%1010.8 hPa
Annapolis, United States Naval Academy, MD14 mi41 minNW 710.00 miFair67°F55°F66%1009.8 hPa

Wind History from W29 (wind in knots)
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Last 24hrCalmSE5CalmCalmCalmS3CalmS6SE6S7SE4S6S5SE4S5S6S6CalmSE9S8S8N7N5N6
1 day agoE5E8E7
G15
E9NE5E6E4E6E4E3E4SE3CalmNW5CalmCalmW3S6W3NW6NW6NW7N3E7
2 days agoSE6SE4S3CalmE12
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Tide / Current Tables for Claiborne, Eastern Bay, Maryland
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Claiborne
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Tue -- 04:52 AM EDT     1.45 feet High Tide
Tue -- 06:55 AM EDT     Sunrise
Tue -- 07:27 AM EDT     Moonrise
Tue -- 11:41 AM EDT     -0.03 feet Low Tide
Tue -- 05:24 PM EDT     1.29 feet High Tide
Tue -- 07:25 PM EDT     Sunset
Tue -- 08:13 PM EDT     Moonset
Tue -- 11:41 PM EDT     0.05 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.20.40.81.11.41.51.31.10.80.50.20-00.10.40.81.11.31.31.10.80.50.30.1

Tide / Current Tables for Baltimore Harbor Approach, Maryland Current
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Baltimore Harbor Approach
Click for Map
Tue -- 12:01 AM EDT     -0.88 knots Max Ebb
Tue -- 03:02 AM EDT     0.00 knots Slack
Tue -- 06:14 AM EDT     0.97 knots Max Flood
Tue -- 06:55 AM EDT     Sunrise
Tue -- 07:27 AM EDT     Moonrise
Tue -- 09:24 AM EDT     -0.00 knots Slack
Tue -- 12:31 PM EDT     -0.95 knots Max Ebb
Tue -- 03:43 PM EDT     0.00 knots Slack
Tue -- 06:38 PM EDT     0.82 knots Max Flood
Tue -- 07:25 PM EDT     Sunset
Tue -- 08:14 PM EDT     Moonset
Tue -- 09:36 PM EDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.9-0.8-0.5-00.40.810.90.60.2-0.3-0.7-0.9-0.9-0.7-0.30.10.50.80.80.60.3-0.2-0.6

Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Mid-Atlantic    EDIT
Geos

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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weather_mapweather_map weather_map

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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.