Thursday, January24, 2019 L-36.com


Marine Weather and Tides
Grasonville, 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 1:04 AM EST (06:04 UTC) Moonrise 9:39PMMoonset 9:51AM Illumination 89% 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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ANZ540 Eastern Bay- 1237 Am Est Thu Jan 24 2019
.gale warning in effect through this afternoon...
Overnight..S winds 20 kt with gusts to 40 kt. Waves 2 to 3 ft. Rain.
Thu..S winds 20 to 25 kt with gusts to 45 kt... Becoming nw 15 to 20 kt with gusts to 35 kt in the afternoon. Waves 3 ft. Rain. Vsby 1 nm or less.
Thu night..W winds 10 to 15 kt. Gusts up to 30 kt... Diminishing to 20 kt after midnight. Waves 1 to 2 ft.
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..E winds 5 to 10 kt...becoming S in the afternoon. Gusts up to 20 kt. Waves 1 ft.
Sat night..S winds 10 kt with gusts to 20 kt. Waves 1 ft.
Sun..W winds 5 to 10 kt. Waves 1 to 2 ft.
Mon..S winds 5 to 10 kt. Waves 1 ft.
ANZ500 1237 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 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 240217
afdphi
area forecast discussion
national weather service mount holly nj
917 pm est Wed jan 23 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 Thursday morning
Evening update: hourly temperature forecasts have been a bit of
a challenge this evening as periodic breaks in the lower clouds
have allowed certain (primarily) inland locations too cool more
than expected. However, an increasing southerly gradient
combined with more robust cloud cover should result in a general
warming trend as we head into the overnight. Also reduced pops
nw of the i-95 corridor for the evening period, as hi-res
guidance has continued to slow the onset of prefrontal
precipitation (generally after 06z with some guidance including
the hrrr rap holding off until around 09z).

Southerly winds have also begun to increase along coastal areas
this evening with acy already gusting to around 30 kts. These
winds will further increase through the overnight into Thursday
morning, with speeds also increasing inland (albeit to a lesser
extent).

Going forecast headlines in good shape... See discussion below:
low pressure will track across quebec
canada tonight with a cold front arriving in our area toward
daybreak. The overall system is slower and therefore a delay in
the precipitation has resulted. This has allowed temperatures to
warm even more though especially the southern areas with around
60 degrees across southern delaware this afternoon (up to near
freezing in the poconos). A look at mesonet data shows much of
carbon county is above freezing and therefore the winter weather
advisory has been cancelled as additional warming is expected.

For monroe county, opted to extend the winter weather advisory
through 7 pm given several locations closer to freezing still.

Any icing that occurs is expected to be light, and additional
warming through the night will allow just plain rain to occur.

A robust low-level jet will continue to maintain warm air advection
through the night. As this occurs, southerly flow will likely
increase especially in the coastal plain and the higher terrain such
as the poconos. The combination of a southerly breeze and warm air
advection should result in temperatures rising through the night.

There will also be an increase in the moisture advection as deep
moisture overspreads our area. The main forcing looks to arrive
later tonight and especially during Thursday, therefore much of the
rain that arrives from the west tonight should be on the lighter
side. Given the slower trends, significantly slowed the eastward
increase in the pops especially through this evening. Low
temperatures should occur early this evening, then as mentioned
should tend to rise.

Short term 6 am Thursday morning through Thursday night
An upper-level trough arriving from the west has a substantial wind
field associated with it. Low pressure will track well to our north
during Thursday, however its cold front will be working its way
across the region. Very strong southerly low-level flow in advance
of the front will continue to advect warm and unusually moist air
into the area. The precipitable water values are forecast to near
1.5 inches ahead of the front, which is very impressive for this
time of the year. This will result in an area of heavier rain from
west to east.

A low-level jet of 50-80 knots (500 mb jet streak of around 100
knots), moves across much of the area. In addition, a 170-180 knot
250 mb jet arriving from the west places our region in the very
favorable right entrance region. This all points to a corridor of
strong and deep ascent, which will be enhanced by a band of strong
850-700 mb frontogenesis. There are also notable pressure rises
behind the front. The forecast soundings show meager instability in
advance of the front, therefore despite a narrow convective-looking
line with the front little or no lightning is expected (perhaps a
better chance for some lightning near or off the coast). For now,
did not include thunder given the meager instability reducing the
updraft strength. The greatest rainfall rates should be mostly with
the strongly forced line as it quickly moves eastward across the
area. The QPF is generally 1 to 2 inches during the day Thursday
across the area, with most of this occurring in a 3-6 hour period at
any particular location. For the flooding risk, see the hydrology
section below.

Winds will also be gusty in advance of the front, especially where
surface temperatures are into the 50s as mixing will be more
efficient within the presence of a low-level jet. The strongest wind
field is especially across our eastern to southern zones, and given
the mixing potential (depth and duration) opted to issue a wind
advisory for Thursday morning for monmouth county south to CAPE may
and cumberland counties then much of our eastern maryland shore and
delaware counties. The strongest winds may be just inland from the
coasts as the cooler waters may reduce the mixing some at the land-
water interface. Elsewhere, gusty winds should occur, however there
is less confidence in 40+ knot wind gusts. In addition, any
convectively-induced precipitation may at least partially mix down
some of the very strong winds from aloft for a brief time. High-res
guidance generally shows the low-topped convective line
strengthening into the i-95 corridor eastward as it encounters
warmer air and the stronger wind field.

The front quickly moves offshore during the afternoon with
precipitation ending quickly behind it, and colder air will filter
in. Depending on how quickly the precipitation ends in the wake of
the front, may see a brief changeover to snow showers before ending
especially in the far northwest zones. As of now, the thinking is
that the bulk of the precipitation ends before a changeover to snow
can occur.

Temperatures will surge in advance of the front, with readings in
the 50s to near 60 southeast of mostly the fall line. However,
temperatures will fall behind the front especially toward later in
the afternoon and evening, with lows below freezing virtually
everywhere Thursday night. Skies should clear Thursday
evening night, although some lingering moisture may keep the lower
clouds present in the far northwestern zones. Some flurries or a few
snow showers are possible especially in the poconos as low-level
northwesterly flow occurs along with cold air advection.

Long term Friday 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 02z Thursday through Monday
The following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

Tonight... Conditions will deteriorate to MVFR overnight. Rain
chances increase from northwest to southeast, especially after
midnight-3am. South winds around 10 to 15 kts, gusty winds
expected near southeast of phl especially acy. Southwesterly
llws anticipated through the night.

Thursday... Ifr restrictions will continue through at least early
afternoon, with rain (heavy at times). Southwesterly llws will also
continue through the morning. Conditions are expected to improve
rapidly during the afternoon with the passage of a cold front.VFR is
possible late. Southwest winds 10 to 20 kts with higher gusts before
the frontal passage, becoming northwest afterward.

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
Small craft advisory conditions through tonight, then upgraded to a
gale warning for Thursday morning to early Thursday afternoon.

An intense wind field will accompany a cold front that moves across
our area on Thursday. Ahead of this front, very strong south to
southwest winds will overspread the area with this peaking mainly
Thursday morning. It is challenging regarding how much of the wind
is able to mix down to the surface given strong warm air advection
over the much cooler waters. The forecast soundings indicate a
rather limited mix layer, however very strong winds are just above
the surface. In addition, a narrow line of low-topped convection
(probably little or no lightning) will accompany the front later
Thursday morning. Stronger winds could mix down with this. Given the
intense wind field forecast, opted to go with a gale warning for all
waters for a portion of Thursday. Small craft advisory conditions
will then follow through Thursday night as much colder air follows
(although not as cold as the previous cold front).

Outlook...

Thursday night... The rain moves out and northwest winds diminish,
but seas will likely remain above advisory criteria through the
night.

Friday-Saturday...VFR. Winds mainly out of the west and northwest with
gusts at or below 20 kt. High confidence.

Saturday night-Sunday... Rain or snow showers possible ahead of a cold
front. Localized ceiling and visibility restrictions possible with
mainly MVFR conditions but brief periods of ifr possible. Winds shift
to S then SE but gusts remain under 20 kt. Moderate confidence.

Sunday night-Monday... MainlyVFR or MVFR conditions currently expected
with isolated rain or snow showers possible. Moderate
confidence.

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 from 4 am est Thursday through Thursday afternoon
for paz061-062-070-071-101>106.

Nj... Flood watch from 4 am est Thursday through Thursday afternoon
for njz001-007>010-012>020-026-027.

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

De... Flood watch from 4 am est Thursday through Thursday afternoon
for dez001.

Wind advisory from 6 am to noon est Thursday for dez002>004.

Md... Flood watch from 4 am est Thursday through Thursday afternoon
for mdz008.

Wind advisory from 6 am to noon est Thursday for mdz012-015-
019-020.

Marine... Small craft advisory until 6 am est Thursday for anz430-431-
450>455.

Gale warning from 6 am to 1 pm est Thursday for anz430-431-
450>455.

Synopsis... O'brien
near term... Carr gorse
short term... Gorse
long term... O'brien
aviation... Kruzdlo carr o'brien
marine... Kruzdlo o'brien
hydrology...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
TPLM2 - Thomas Point, MD 10 mi64 min SSE 21 G 22 45°F 38°F1012.2 hPa (-2.1)45°F
CPVM2 11 mi52 min 47°F 47°F
APAM2 - 8575512 - Annapolis, MD 14 mi46 min 49°F 1011 hPa
CA2 - 8571892 - Cambridge, MD 23 mi52 min 53°F 35°F1012.7 hPa
TCBM2 - 8573364 - Tolchester Beach, MD 23 mi46 min S 12 G 17 52°F 34°F1011.3 hPa
BSLM2 - Chesapeake Bay, MD 25 mi154 min SSE 11 48°F 1013 hPa45°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 28 mi46 min SSE 15 G 17 51°F 1010.5 hPa
FSNM2 28 mi52 min S 12 G 16 52°F 1010.2 hPa
BLTM2 - 8574680 - Baltimore, MD 32 mi52 min SW 2.9 G 6 47°F 37°F1010.4 hPa
COVM2 - 8577018 - Cove Point LNG Pier, MD 34 mi52 min S 19 G 21 46°F 1013.1 hPa
SLIM2 - 8577330 - Solomons Island, MD 40 mi46 min SSE 12 G 15 53°F 39°F1011.8 hPa
WASD2 - 8594900 - Washington, DC 41 mi46 min S 6 G 8.9 52°F 35°F1010.5 hPa
DRSD1 - Delaware Reserve, DE 45 mi154 min S 11 56°F 1014 hPa51°F
BISM2 - 8571421 - Bishops Head, MD 47 mi46 min SSE 12 G 13 42°F 1013.2 hPa

Wind History for Cambridge, MD
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Bay Bridge Field, MD8 mi84 minS 17 G 2410.00 miMostly Cloudy50°F50°F100%1012.9 hPa
Easton / Newman Field, MD11 mi67 minS 18 G 2210.00 miOvercast and Breezy55°F51°F89%1014.2 hPa
Annapolis, United States Naval Academy, MD14 mi70 minS 13 G 1810.00 miOvercast49°F44°F83%1012.2 hPa

Wind History from W29 (wind in knots)
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1 day ago--------------N5N6N7--N4CalmNW3CalmS4--SE11S6S6S9S8S8S8
2 days ago----------------W17
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Tide / Current Tables for Claiborne, Eastern Bay, Maryland
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Claiborne
Click for Map
Thu -- 01:03 AM EST     -0.25 feet Low Tide
Thu -- 06:16 AM EST     0.85 feet High Tide
Thu -- 07:17 AM EST     Sunrise
Thu -- 09:50 AM EST     Moonset
Thu -- 12:40 PM EST     -0.44 feet Low Tide
Thu -- 05:17 PM EST     Sunset
Thu -- 06:55 PM EST     1.22 feet High Tide
Thu -- 09:38 PM EST     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.2-0.2-0.20.10.40.70.80.80.60.30-0.2-0.4-0.4-0.300.40.81.11.21.10.90.60.2

Tide / Current Tables for Baltimore Harbor Approach, Maryland Current
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Baltimore Harbor Approach
Click for Map
Thu -- 01:21 AM EST     -1.13 knots Max Ebb
Thu -- 04:46 AM EST     0.00 knots Slack
Thu -- 07:18 AM EST     Sunrise
Thu -- 07:38 AM EST     0.83 knots Max Flood
Thu -- 09:51 AM EST     Moonset
Thu -- 10:40 AM EST     -0.00 knots Slack
Thu -- 01:33 PM EST     -0.76 knots Max Ebb
Thu -- 04:23 PM EST     0.00 knots Slack
Thu -- 05:17 PM EST     Sunset
Thu -- 07:40 PM EST     0.98 knots Max Flood
Thu -- 09:39 PM EST     Moonrise
Thu -- 10:48 PM EST     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.9-1.1-1.1-0.8-0.40.10.50.80.80.60.3-0.1-0.5-0.7-0.7-0.5-0.20.30.70.910.80.4-0.1

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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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.